OGA - Queen`s University Belfast
advertisement
Getting about the campus and finding us The meeting will be held in the Medical Biology Centre just off Lisburn Road (building number 33 in the map below. Unfortunately, we are currently midway through some extensive building work and entrance to the building is not as straightforward as it might be … To enter the building, you will have to follow Jubilee Road (unmarked road just to the north of the building) and make your way between the buildings (e.g. at 36a) until you find yourself in the area “behind” the MBC. You can then enter from the west entrance (“back” of the MBC, arrowed). There are some signs – we will endeavour to add some more! The conference meal and disco will take place in part of building 24 (corner of Elmwood Avenue and University Road). List of participants Surname First Name Affiliation E-mail Abbot Abdalla Ageli Alden Ansari Black Bouchenak-Khelladi Brady Brennan Browne Bruns Clifton-Brown Coote Cooke Curran Davis Devaney Diamond Dolan Doohan Doran Downey Duggan Edwards Egan Elmeer Fletcher Fuller Gibson Gioria Henley Hennerty Hodkinson Irvine Kelly Khan Kimberly King-Salter Kumar Lanigan Lupton McCabe McCracken McEvoy McGrath McIvor McMeel Maggs Marchant Matthews Meade Mercer Mitchell Moloney Monaghan Jane M Fatma Keith Khairul Kevin Yannis Aoife Josephine Roy Svenja John Linda Mike Noreen Philip Fiona Mark Liam Fiona Amanda David John Maeve Damian Khalid Hugh Hubert Brian Margherita Beverley Michael Trevor Katherine John Mojibur Sarah Giles Suresh Gary Darach Paul Alistair Ian Helen Lynn Oonagh Chris Robert David Conor Peter Derek Elizabeth Suzanne TCD TCD UCD abbottj@tcd.ie abdallam@tcd.ie UCD UCD TCD UCD UCD UCD QUB TCD TCD UCD Maynooth UCD UCD UCD JIC UCD UCD Maynooth UCD QUB UCD UCD QUB UCD UCD UCD Maynooth UCD TCD UCD Galway UCD TCD UCD TCD TCD TCD UCD Newforge Maynooth Galway QUB Newforge QUB TCD UCD Maynooth Newforge UCD UCD Keithpjalden@hotmail.com Khairulansari@rediffmail.com Kevin.black@ucd.ie boucheny@tcd.ie aoife_brady@hotmail.com Josephine.brennan@ucd.ie Roy.browne@ucd.ie svenja.bruns@gmx.de jcbrown@tcd.ie cootel@tcd.ie noreenmcurran@eircom.net Philip.davis@ucd.ie fiona.devaney@ucd.ie mark.diamond@ucd.ie Liam.dolan@bbsrc.ac.uk Fiona.Doohan@ucd.ie amanda.doran@ucd.ie Cardenalmendoza@hotmail.com m.edwards@qub.ac.uk bulmeer@yahoo.com h.fletcher@qub.ac.uk hubert.fuller@ucd.ie brian.gibson@ucd.ie margheritagioria@yahoo.com Beverley.m.Henley@may.ie hodkinst@tcd.ie irvinekatherine@yahoo.co.uk jkelly@nuigalway.ie mrk6@rediffmail.com kimberls@tcd.ie Giles.Kingsalter@UCD.ie jogis@tcd.ie lanigag@tcd.ie dlupton@tcd.ie paul.mccabe@ucd.ie Alistair.mccracken@dardni.gov.uk ianpmcevoy@yahoo.co.uk Helen.a.mcgrath@nuigalway.ie L.McIvor@qub.ac.uk oonagh.mcmeel@dardni.gov.uk C.Maggs@qub.ac.uk marchanr@tcd.ie davematt00@hotmail.com Conor.v.meade@may.ie Peter.mercer@dardni.gov.uk Derek.T.Mitchell@ucd.ie libby.molony@ucd.ie suzanne.monaghan@ucd.ie Surname First Name Affiliation Moore Moran Moran Morrison Nygard O'Brien O'Sullivan Osborne Parnell Phelan Poage Provan Quinn Ryan Ryan Salamin Sherry Spillane Steer Stengel Stout Touhy Vicuna Wilson Wilson Zangeneh Tom Mary Patrick Liam Lotta Martin Bryan Bruce John Sinead Miranda Jim Mary Eimear Sarah Nicolas Eugene Charles Martin Dagmar Jane Jane Deborah Graham Pamela Nasrin UCD Maynooth UCD Galway QUB UCD UCC UCD TCD Teagasc Maynooth QUB UCD Maynooth UCD TCD UCD UCC UCD Galway TCD UCD Maynooth UCD QUB UCD E-mail Marymoran99@eircom.net Patrick.moran@ucd.ie liam.morrison@nuigalway.ie Lotta.Nygard@mh.se mobrien@grange.teagasc.ie c.spillane@ucc.ie Bruce.Osborne@ucd.ie jparnell@tcd.ie sphelan@kinsealy.teagasc.ie mirandapoage@hotmail.com J.Provan@qub.ac.uk eimsryan@hotmail.com salamin@tcd.ie Eugene.sherry@ucd.ie c.spillane@ucc.ie Dagmar.Stengel@nuigalway.ie stoutj@tcd.ie Jane.Tuohy@ucd.ie Deborah.vicuna@may.ie graham.wilson@ucd.ie p.j.wilson@qub.ac.uk Jayshireen@yahoo.com.uk Wednesday 21st April 1800 – Registration (MBC south foyer) 1900 – 2100 Wine reception and poster session (MBC south foyer) Thursday 22nd April 0900 – 1040 Session 1A (North Lecture Theatre) 0900 – 1040 Session 1B (South Lecture Theatre) 1040 – 1110 Coffee 1110 – 1230 Session 2A (North Lecture Theatre) 1110 – 1230 Session 2B (South Lecture Theatre) 1230 – 1400 Lunch 1400 – 1520 Session 3A (North Lecture Theatre) 1400 – 1520 Session 3B (South Lecture Theatre) 1600 – 1700 Plenary Talk: Colin Fleming – “Genetic Conservation of Irish Trees: Assessing genetic variation” (South Lecture Theatre) 1900 – Conference dinner and disco (Beech Room) Friday 23rd April 0930 – 1030 Session 4A (North Lecture Theatre) 1030 – 1100 Coffee 1100 – 1200 Session 5A (North Lecture Theatre) 1200 Meeting Ends 0930 – 1030 Session 4B (South Lecture Theatre) 1100 – 1200 Session 5B (South Lecture Theatre) Thursday 22nd April Session 1A – North Lecture Theatre 0900 – 0920 Bruns, S Development of blooms of opportunistic green algae (OGA) in Strangford Lough, Northern Ireland, and its assessment by remote sensing 0920 – 0940 Edwards, M Cultivation of Palmaria palmata in Strangford Lough 0940 – 1000 Morrison, L Seaweed – getting to the root of the matter 1000 – 1020 Nygard, C Fucus vesiculosus – a marine species in the brackish Baltic Sea 1020 – 1040 Blake, C A paleoecological approach to determine threats to a protected marine habit – maerl Session 2A – North Lecture Theatre 1110 – 1130 Clifton-Brown, J Measurement of green house gas fluxes from grassland in Ireland 1130 – 1150 Davis, P Title TBC 1150 – 1210 Kumar, S Seasonal changes in soil and plant respiration rate from pasture and arable systems in Ireland 1210 – 1230 Lanigan, G Determining photorespiratory fractionation and effects on carbon isotope discrimination in Senecio species Session 3A – North Lecture Theatre 1400 – 1420 Black K Interactions between water stress and sun-shade acclimation in Sitka spruce seedlings 1420 – 1440 Moran, P The interaction of water deficits and exposure on plants growing on exposed limestone pavement 1440 – 1500 Ryan, S Water availability and the performance of Corylus avenella growing in the Burren, Co. Clare, Ireland 1500 – 1520 Devaney, F Effects of water supply on three dune slack species, Hydrocotyle vulgaris, Filipendula ulmaria and Potentilla anserine Thursday 22nd April Session 2B – South Lecture Theatre 0900 – 0920 Mercer, P Cereal disease spectra in Northern Ireland over the past 25 years 0920 – 0940 McCracken, A Sudden Oak Death – a major threat from a new disease 0940 – 1000 Moran, M Antioxidant levels in two barley cultivars showing varying sensitivity to physiological leaf spot 1000 – 1020 O’Brien, M Mould growth on baled grass silage 1020 – 1040 Browne, R An in vitro assay for detecting resistance to Fusarium head blight and associated mycotoxins in wheat Session 2B – South Lecture Theatre 1110 – 1130 Gibson, B Calcium and iron phosphate solubilization by ectomycorrhizal fungi 1130 – 1150 King-Salter, G Activity of arbuscular mycorrhizal fungi in an Irish grassland after long-term phosphorus fertilisation 1150 – 1210 Duggan, J The use of spent mushroom compost as an organic manure and nutrient source on potatoes 1210 – 1230 Olave, R Targeting tree seedlings through propagation methods and outplanting performance in Northern Ireland, Falkland Islands and Tierra del Fuego Session 3B – South Lecture Theatre 1400 – 1420 Diamond, M Plant programmed cell death requires de novo protein synthesis 1420 – 1440 Moloney, E Investigating the role of calcium in plant programmed cell death 1440 – 1500 Irvine, K Taxonomic comparison and phytosociological analysis of Puccinellia fasciculate, P. distans and P. maritime 1500 – 1520 Marchant, R Spread of human impact on the Irish vegetation: a palaeoecological perspective Friday 23rd April Session 4A – North Lecture Theatre 0930 – 0950 Salamin, N Estimating speciation and extinction rates from phylogenetic trees: a Markov Chain Monte Carlo approach 0950 – 1010 Hodkinson, T Large phylogenetic trees of the grassfamily: a multigene approach 1010 – 1030 McIvor, L Biogeography, phylogeny and evolutionary radiation in the red algal tribe Ceramieae Session 5A – North Lecture Theatre 1100 – 1120 Ryan, E Pollen mediated gene flow in ryegrass 1120 – 1140 Matthews, D Innate zinc tolerance in Glyceria fluitans, an investigation using hydroponic experiments, protoplast analysis and AFLP fingerprinting 1140 – 1200 Stout, J Breeding system of invasive Rhododendron ponticum in Ireland Session 4B – South Lecture Theatre 0930 – 0950 Henley, B Transcription of the succinate dehydrogenase subunit 4 (sdh4) gene in A. majus: RNA editing and co-transcription with the cytochrome oxidase subunit 3 (cox3) gene 0950 – 1010 Curran, N A model for the study of calcium fluxes in plant cells 1010 – 1030 Doran, A flubber (flb), a new root hair mutant in Arabidopsis thaliana Session 5B – South Lecture Theatre 1100 – 1120 Abbott, J Improving the micropropagation of selected mature Irish ash (Fraxinus excelsior) 1120 – 1140 Elmeer, K The effects of sucrose concentration and sodium chloride on callus formation and somatic embryogenesis of an F1 cucumber hybrid 1140 – 1200 Vicuna, D Genetic transformation of apple with a pathogenesis-related barley peroxidase gene and its effects on stress responses and development Paper Abstracts Genetic Conservation of Irish Trees: Assessing genetic variation Colin C. Fleming, Graham Muir and Stephen Clarke Applied Plant Science Division, Agriculture and Food Science Centre, Newforge Lane Genetic variation within tree species is a fundamental component of forest biodiversity, but effective management and conservation of this resource has only been achieved for relatively few tree species. Numerous factors have acted to produce existing patterns of genetic variation in Irish woodland and characterising this resource is key to developing genetic conservation strategies for our native tree species. Using data from a range of native species including ash, oak and hawthorn, we show the importance of identifying suitable molecular markers before attempting to measure genetic variation in woodlands. Once an effective marker has been selected we can measure the amounts and pattern of genetic variation in woodland species. This information allows us to start to develop long-term conservation strategies which encompass issues such as choice of seed source for replanting, establishment of forest reserves and gene banks, conservation of small and isolated populations and assessing the impact of exotic provenances. Development of blooms of opportunistic green algae (OGA) in Strangford Lough, Northern Ireland, and its assessment by remote sensing Bruns S, McIlveen CD, Dring MJ Queen’s University Marine Laboratory Green tides dominated by green algal genera like Ulva, Cladophora and Chaetomorpha can form free floating mats in shallow waters and/or attached large mats on soft intertidal sediments. Field and laboratory studies at several sites in Strangford Lough during the summer and autum of 2002 and the spring of 2004 show the biological and physiological characteristics of the rapidly growing blooms of attached green algae dominated by Ulva sp. (incl. forma Enteromorpha spp.). The present study focuses on the development of opportunistic green algae (OGA) by measuring the cover at different heights on the shore at two sites in Strangford Lough. In addition, the absorption spectrum of mats with up to 25 layers of Ulva on top of each other was measured. The absorbance ratio 554:679 nm was proportional to the number of layers and could be used to determine the biomass of this bloomforming alga by using a spectroradiometer in the field. The results may permit the stage of bloom development and the balance between OGA and seagrasses to be determined by remote spectral techniques. Cultivation of Palmaria palmata in Strangford Lough Edwards MD, Dring MJ and Browne KL Queen’s University Marine Laboratory Palmaria palmata, commonly known as dulse or dillisk, has traditionally been used as a nutritious food source for many years in Ireland. Recently, research has been completed to assess suitable and cost-effective growing techniques in Strangford Lough. This work continues, and focuses on cultivation of Palmaria from spores settled on and attached to a culture system in Strangford Lough. Aspects of the research include seasonal growth rates of the plants, manipulation of spore density and inducing reproduction out of season. Existing harvests of plants have produced good yields. After seven months, 16.48 m of string yielded 6.04 kg (wet weight) of plant material. This is a yield of 3.67 g cm-1 string. Work is currently underway to find optimum culture conditions for growing the spores during the nursery period in the laboratory. This involves growing spores in a range of irradiance and nutrient combinations. Other experiments including the effect of nursery time on the survival of spores and the effect of harvesting on the local Palmaria populations are being carried out. This research is supported by the Northern Ireland Department of Education and Learning and Dolphin Sea Vegetable Company through a CAST award. Seaweed - getting to the root of the matter Liam Morrison1, Martin Feely2, Matthew J. Dring3 and Dagmar B. Stengel1 1Department of Botany, Martin Ryan Institute, National University of Ireland, Galway 2Department of Earth & Ocean Sciences, National University of Ireland, Galway 3School of Biology & Biochemistry, Queens University Belfast This project marks the first-ever interdisciplinary study of the mode of attachment of seaweed to its bedrock substrate. Preliminary investigations indicate that seaweed rhizoids do indeed penetrate into granite and limestone bedrock in the Galway Bay area. This penetration causes physical disaggregation and fragmentation of the constituent minerals in the rock substrate. Furthermore, this physical interaction suggests there is also the potential for biochemical interaction between algal tissue and bedrock. This is in stark contrast to the current view that chemical species are taken up solely from seawater over the thallus surface. The aim of this novel research is to characterise the physical and chemical nature of the interface between a range of seaweeds and rock types. Thinsection studies of the granite-holdfast interface reveal evidence for the penetration of the algal tissue along, (a) cleavage planes of biotite and (b) intercrystalline boundaries of feldspar and quartz. Furthermore, the cleavage flakes of biotite are bent and separated by the seaweed holdfast; this is unequivocal evidence of biomechanical interaction. The mix of analytical procedures and methods in the context of the project subject matter is novel and innovative and, although this research will be predominantly carried out in the diverse habitats of Galway Bay, it potentially has substantial international implications. Fucus vesiculosus – A marine species in the brackish Baltic Sea CA Nygard Queen’s University Marine Laboratory Fucus vesiculosus (Phaeophyta) is a marine alga which is able to tolerate the low salinity of the Baltic Sea. Few other macroalgae can stand this low salinity and therefore the belt-forming F. vesiculosus has become an important keyspecies in the Baltic ecosystem. It forms breeding ground, shelter and food for a great amount of the macrofauna and fishes in the region. The low salinity gives the Baltic F. vesiculosus a smaller thallus and in the northern Baltic, where the salinity decreases even more, the plants lack their characteristic bladders. The salinity even affects the physiology of the plants, with significant lower photosynthesis in the Baltic Sea compared to the Atlantic. Photosynthesis was measured as oxygen evolution and as ETR (electron transport rate). Comparisons were done between the Baltic and Atlantic F. vesiculosus regarding the tolerance to environmental disturbances, such as ultraviolet-B radiation (UV-B, 280-320nm) and pollution by the heavy metal lead (PbCl2). The heavy metal decreased the photosynthesis in all salinities, but most pronounced in higher salinity. Similar results were obtained with UV-B radiation, but the differences were smaller here. Further work will follow to examine if different photoinhibition is acting in this case. A transfer experiment between Baltic and Atlantic seawater revealed that even then Baltic F. vesiculosus has adapted to a life in the low salinity it still prefers a more marine environment. This since the low photosynthesis of the Baltic plants increased to almost the same level as the Atlantic F. vesiculosus when they where transferred to Atlantic water. Atlantic F. vesiculosus instead decreased photosynthesis in Baltic water, and even died within 7 weeks. A paleoecological approach to determine threats to a protected marine habit – maerl Charmaine Blake and Christine Maggs School of Biology and Biochemistry, Queens University Belfast Maerl is a general term used for loose-lying subtidal beds of nodular coralline red algae that can cover large areas in suitable conditions. This case study of a maerl bed in Belfast Lough takes a novel approach to evaluate threats in the marine environment to these habitats, which an be used by government bodies to ensure their future protection. We determined by radiocarbon dating that a large maerl bed in Belfast Lough was killed around 1845 and the most likely cause of this was extensive channel dredging for shipping. Measurement of Green House Gas Fluxes from grassland in Ireland John Clifton-Brown1, Phill Davis2, Mohamed Abdulla1, Fabrizio Albanito1, James Burke3, Alison Donnelly1, Dan Lovett4, Orla Fenlon1, Tony Fortune3, Eddie Jordan4, Anne McCourt1, Frank O’Mara4, Bruce Osborne2, Mike Williams1 and Mike Jones1 1 Department of Botany, Trinity College, University of Dublin 2 Department of Botany, University College Dublin 3 Teagasc, Oak Park Research Centre 4 Department of Animal Science and Production, Lyons Research Farm, University College Dublin Ireland’s commitment to the Kyoto protocol warrants a detailed and verifiable assessment of greenhouse gas (GHG) fluxes from grasslands. The principal GHGs associated with grasslands are CO2, N2O and CH4. Eddy covariance measures vertical fluxes of CO 2 providing a measure of net ecosystem exchange (NEE). With careful interpretation it can provide an assessment of the activity of carbon sinks or sources. Measurements N2O fluxes are being made using a closed static chamber technique. Measurements of CH4 emission from grazing animals have been made semi-continuously throughout the 2003 grazing period. Our initial measurements show that on the grassland annual net uptake was 8 t CO 2 [C] ha-1 5 of which was removed by silage and grazing. The remaining 3 t C must be accounted for in the (i) CH 4 emitted by the grazing cattle (ii) C in meat exported from grazing cattle (iii) C sequestration into the roots and soil and (iv) leaching of dissolved organic C. Mean CH 4 emissions were found to range from 200 to 400 litres CH4 animal-1 d-1. Despite these large volumes it only accounts for about 48 kg C ha-1 for the grazing period. Live weight gain was 100 kg animal-1 during the grazing period and we estimate that meat accounts for 42 kg C ha-1. Simple accounting shows that 2.9 t C ha-1 is being stored in stubble, below ground biomass and soils. Currently no estimate of leached dissolved organic C is being made, however we expect this to be rather small (<100 kg C ha -1 y-1) and therefore it appears this grassland is a significant sink for CO 2. Title Phill Davis1, John Clifton Brown2, Suresh Kumar2, Mike Williams2, Mike Jones2 and Bruce Osborne1 1 Botany Department, University College Dublin 2 Botany Department, Trinity College Dublin, University of Dublin Typically arable soils have a low organic carbon content, which can be attributed to the long-term losses associated with agricultural management practices. Several management practices, including tillage operations, the export of biomass in harvestable products and little or no plant cover between cropping rotations, are associated with significant annual carbon losses. Tillage operations that disturb the soil cause a large short-term pulse in CO2 emissions that may, on an annual basis, be insignificant when compared with the longer-term stimulation of soil respiration. Harvested biomass may also contain more carbon than the ecosystem respires annually and its export should be limited. A compounding factor is the low lignin content of many crops, resulting in the rapid decay of plant biomass. In order to improve the carbon sequestration potential of arable ecosystems management practices must be modified to increase carbon storage and reduce carbon losses. Here we present the initial years data from a replicated experiment comparing the effects of conventional ploughing and non-inversion tillage as well as straw incorporation on Net Ecosystem Exchange (NEE) of a spring barley crop. NEE was measured using two mobile flux towers each associated with both management practices (conventional and non-inversion tillage) giving two replicated treatments. Seasonal changes in soil and plant respiration rate from pasture and arable systems in Ireland Kumar, S., Clifton-Brown, J.C. Davis, P., Williams, M., Osborne, B., Burke, J.I. and Jones, M.B. 1 Department of Botany, Trinity College, University of Dublin 2 Department of Botany, University College Dublin 3 Teagasc, Oak Park Research Centre After photosynthesis, soil respiration is the most significant component of the global C cycle and is equivalent to approximately 10% of the atmospheric CO2 pool. Soil respiration flux (CO2) integrates root and microbial activity and represents total belowground C metabolism. Irish agriculture comprises pastures and arable crops as major patterns of land use. The effect of different land-use practices, when combined with measurements of soil respiration, can provide an indication of the likely consequences of soil management on soil organic carbon (SOC). The aim of this project is to quantify seasonal variations in soil CO2 fluxes and concurrent changes in soil temperature soil water content and carbon input from the vegetation. Relationships will be used to parameterise a model for different land-uses. Measurements of soil CO2 flux were performed with the CIRAS-I (PP systems, UK) gas exchange system fitted with the soil respiration chamber on the two separate agricultural systems: a grazed Lolium perenne dominated pasture and spring barley crop grown under conventional and reduced tillage systems. Preliminary results for the grassland shows that with the onset of spring there is an increase in soil CO2 flux and this is associated with rising soil temperature. During mid summer some decoupling of the relationship between respiration rate and temperature occurs during periods of drought. Obviously there are complex interactions between soil moisture and soil temperature. These measurements taken along with parallel measurements of soil carbon stocks, root biomass, soil temperature and moisture content will allow us to parameterise a mechanistic model to predict CO2 efflux from the soil. Determining photorespiratory fractionation and effects on carbon isotope discrimination in Senecio species. Gary J. Lanigan1, Nicholas Betson2, and Howard Griffiths2. 1 Trinity College Dublin 2 University of Cambridge The effect of photorespiration on instantaneous photosynthetic discrimination and gas-exchange characteristics was investigated for three Senecio species of contrasting life-form (S. squalidis, S. cineraria and S. greyii). The rate of photorespiration was manipulated by altering the O2 partial pressure (pO2). Observed discrimination (Δobs) decreased relative to modelled discrimination (Δi) at higher pO2, indicating a greater contribution from 13C-depleted photorespiratory CO2. These effects were observed to be species-specific, with a minimal effect of elevated pO2 on Δobs of S. greyii. The photorespiratory fractionation factor (f) was estimated by developing a model for instantaneous discrimination, which also allowed us to resolve the impact of refixation at low stomatal conductances for all three species. We define this operating or apparent fractionation factor as fa, with a value of +9 ‰ for S. squalidis and S. cineraria and +11 ‰ for S. greyii. Substituting these values of f in the conventional Farquhar model for leaf-level discrimination gave a good correlation between Δobs and Δi. We also explored the large scale impact of photorespiratory discrimination at a mesocosm level, and show that the isotopic composition of CO2 in air within and above canopies is likely to reflect the daily extent of photorespiration and refixation under natural conditions. Interactions between water stress and sun-shade acclimation in Sitka spruce seedlings Kevin Black, Phill Davis, Pat Doherty and Bruce Osborne Department of Botany, University College Dublin Gas exchange and chlorophyll fluorescence techniques were used to evaluate the acclimation capacity of Sitka spruce seedlings to water stress under sun and shaded conditions. The onset of water stress resulted in a decreased stomatal and mesophyll conductance and photosynthesis in plants exposed to full sunlight and 50 % shade. In water stressed sun grown seedlings the photochemical efficiency of PSII showed decreases in Fv/Fm after prolonged stomatal closure and non-photosynthetic electron transfer. Although stomatal, mesophyll and hydraulic conductance recovered in these plants, following re-wetting and a recovery period, net photosynthesis was still inhibited due to a high degree of non-photosynthetic energy dissipation and a reduction of Fv/Fm. In contrast, water stress in shade plants exhibited a transient decrease in stomatal and mesophyll conductance resulting in full recovery of photosynthesis following re-wetting and a recovery period. While there was a 20 % increase in non-photosynthetic electron transfer, photoinhibition in water stressed shade plants was primarily associated with mesophyll conductance limitation rather than inherent changes in PSII efficiency. These results suggest that lower light intensities and a reduced VPD, under shaded conditions, protected photochemical pathways against inactivation while exposure to full sunlight caused photodamage following stomatal closure. In addition, the inability of seedlings to exhibit any short term (2-3months) photosynthetic acclimation to the different light environments suggests that water may be a limiting factor for seedling establishment, particularly in seedlings exposed to full sunlight. The interaction of water deficits and exposure on plants growing on exposed limestone pavement Patrick Moran, Sarah Ryan, Roger Turner, Bruce Osborne Department of Botany, University College Dublin In situ measurements made in the Burren, an area of open Karst limestone, located in Co. Clare, Ireland, indicated that the substrate volumetric water content (VWC) was comparable to semi-arid habitats, despite the prevailing oceanic conditions. This is due to minimal storage of water associated with the limestone aquifer. Following heavy rainfall events, which occur regularly every 6 - 9 days during the summer, there were transient increases in VWC, followed by a rapid decline (with rates of up to 0.5% per hour). Chlorophyll fluorescence measurements carried out on Teucrium scorodonia, one of the most commonly occurring plants on the open pavement, before and after one of these events (23mm of rain in 3 days) indicated that increases in VWC were associated with a 20% increase in PSII/ decrease in NPQ. Laboratory experiments yielded similar results. In addition, maximum photosynthetic rates showed a similar response to VWC, but of greater magnitude (a 10 fold increase in Amax following a simulated rainfall event). Under typical field conditions (VWC of approximately 15% and PAR values ranging between 200 and 2000 μmol m -2s-1 on the day measurements were made), photosynthesis had a relatively low light saturation point (between 200 and 300 μmol m-2s-1). These results suggest that limited water availability, rather than exposure, may have an important role to play in governing the species composition of the Burren limestone pavement. Water availability and the performance of Corylus avellana growing in the Burren, Co. Clare, Ireland. Sarah Ryan, P., Moran and B., Osborne. Department of Botany, University College Dublin The Burren is situated on the western seaboard of Ireland, and experiences a high rainfall (~1600mm per year). On the exposed limestone regions of the Burren, plants experience water shortages cyclically due to minimal storage of water by the limestone substrate. Despite frequent dry periods hazel scrub is considered to be increasing its range in many areas. Preliminary investigations of common species growing on the limestone pavement have indicated that these plants are sensitive to water availability via rainfall. To assess the significance of water availability on the performance of hazel we have used assessments of fluorescence and photosynthesis on plants growing in situ and ex situ, coupled with measurements of soil water content, shoot water potential and other climatic variables. The results so far show that fluctuations of VWC (<10% to <50%) in the greenhouse appear to have no affect on the quantum yield of PSII (ΦPSII). Values for ΦPSII from the field measurements were high despite a low mean VWC (14.4% +/- 2.87). Ex situ measurements of maximum photosynthetic rate (Pm) decreased with decreasing levels of VWC (<20%). In the field Pm measurements were higher and less sensitive to low levels of VWC (< 20%). Results indicate that in situ, hazel has the ability to withstand extended periods without water. In the greenhouse photosynthetic performance of hazel was affected by reduced water availability and therefore suggests that hazel growing ex situ is sensitive to soil water deficits. Further measurements in situ and ex situ and implementation of some small scale watering treatments will provide more detailed information about the relationship between water limitation and the performance of hazel in the Burren. Effects of water supply on three dune slack species, Hydrocotyle vulgaris, Filipendula ulmaria and Potentilla anserina Devaney, F.M., Moran, B.M. and Otte, M.L. Department of Botany, University College Dublin The Alder Marsh, North Bull Island, County Dublin is a dune slack with unique vegetation. Recent observations suggest that the Alder Marsh is drying out. The waterlogged condition of dune slack soils is an important determinant of the vegetation and since the marsh provides a habitat for plants such as Ophioglossum vulgatum (Adder’s tongue fern) and orchids like Epipactis palustris (Marsh Helleborine) and Anacamptis pyramidalis (Pyramidal Orchid), it is important to investigate what effects a change in water supply would have on the vegetation. This experiment investigated the effects of water supply on H. vulgaris (Marsh Pennywort), F. ulmaria (Meadowsweet) and P. anserina (Silverweed). Each species was subjected to five water treatments – 20, 40, 60, 80 and 100% of the saturation weight of the sand and compost mixture. All plants were taken from the marsh. Growth parameters were measured on a weekly basis and nitrogen, calcium and potassium levels within the shoots were also analysed. Water supply had an affect on all three plant species. H. vulgaris had optimum growth at the intermediate treatment (60%), P. anserina had optimum growth at the 80% treatment and F. ulmaria had optimum growth at both the 100 and 80% treatments. Almost all plants died at the 20 and 40% treatments. These results suggest that if the marsh dries out these three species and others similarly dependent on wet soil conditions may die out due to increasing competition from more drought-loving species and from an inability to cope with a lower water supply. Cereal disease spectra in Northern Ireland over the past 25 years. P.C. Mercer & A. Ruddock Applied Plant Science Division, Agriculture and Food Science Centre, Newforge Lane The three main cereal crops, spring barley, winter barley and winter wheat were surveyed for disease, cultivar popularity and frequency of fungicide application at different times from 1968-2000. The raison d’être for the surveys is discussed. The most striking results were the almost complete replacement by Rhynchosporium secalis (leaf blotch) of Blumeria graminis (mildew), what had previously been the major disease of spring barley; the predominance of Mycosphaerella graminicola (septoria tritici blotch) over the previously predominant Phaeosphaeria nodorum (septoria nodorum blotch); and the consistency from year to year of R. secalis (leaf blotch) in winter barley. Other diseases caused problems in individual years, probably as a result of favourable weather conditions and susceptible cultivars. Spring barley and winter wheat cultivars followed a relatively smooth pattern of introduction and replacement. Those of winter barley were more long-lasting. There was a tendency towards a rise in resistance to the major diseases in spring barley, but not in the other two cereals. All cereals were sprayed increasingly more frequently as time progressed. Sudden Oak Death – a major threat from a new disease Alistair R McCracken Applied Plant Science Division, Dept. Agriculture & Rural Development, Newforge Lane Sudden Oak Death (SOD) is caused by the fungus Phytophthora ramorum. It is a disease which was first identified in California (USA) in 2000 in the natural tan and coastal oak forests. In California the disease has had a major environmental impact, with large numbers of trees being killed. P. ramorum was first detected in Europe in 2001 on rhododendron. Since then it has been found on a wide range of hosts. The UK has extensive screening programmes and all infected plants are destroyed. In Great Britain the pathogen has been detected in wild plants including a small number of mature beech, holm oak and horse chestnut. An extensive survey of Northern Ireland forests and parklands has been carried out. To date P. ramorum has not been detected in the wild. There is one positive case on wild rhododendron in the Republic of Ireland. In addition, imported host plants, particularly rhododendron and vibernum are tested for the presence of the pathogen. In NI P. ramorum has only been detected on plants in trade. Suspect plants are tested using both isolation and molecular methodologies. P. ramorum has the potential to cause major environmental damage similar to that caused by Dutch Elm Disease. However, attempts to control the spread of the pathogen have often met with opposition. Antioxidant levels in two barley cultivars showing varying sensitivity to physiological leaf spot. Mary G. Moran, J.I. Burke & P.J. Dix Institute of Bioengineering and Agroecology, NUI Maynooth Physiological leaf spot (PLS) as a disease was first noticed in the 1980’s. It has become more prevalent since then and affects winter and spring barley crops worldwide. The symptoms are similar to Ramularia collo-cygni and net blotch infection but no microorganisms have been isolated from affected leaves. This has lead to speculation that the stress is of an environmental nature. In this study two cultivars of spring barley (Hordeum vulgare L.) with differing sensitivity to PLS were grown in field trials in Oak Park. The leaf material was harvested over four weeks and analysed for various antioxidants, scavenging enzymes and other stress indicators. The sensitive cultivar, Cooper, shows significant increases in guaiacol peroxidase activity at the onset of symptoms in comparison with the more resistant cultivar, Crusader. Mould Growth on Baled Grass Silage M. O’Brien1, 3, P. O’Kiely1, P.D. Forristal2 and H. Fuller3 1Teagasc, Grange Research Centre, Dunsany, Co. Meath; 2Teagasc, Crops Research Centre, Oak Park, Co. Carlow; 3Department of Botany, University College Dublin Baled grass silage is used extensively by Irish farmers as winter fodder for livestock. Widespread mould contamination of bales has been reported but the identity and extent of occurrence of fungi on big bales has not been adequately documented. In March 2003, a preliminary study investigated the prevalence and identity of visible fungal colonies on the surface of baled silage on 35 farms in the Irish Midlands, along a route between Clonmel and Navan. Sixty-four bales were subjected to detailed examination following removal of the plastic wrap. Mould colonies were observed on 58 of the 64 bales (88%) and from one to twelve colonies were seen per bale (mean: six colonies per bale). A total of 337 fungal colonies was sampled, resulting in 480 isolates. The fungus most frequently isolated was Penicillium roqueforti, representing 55% of all isolates and present on 80% (51/64) of bales examined. Other moulds isolated were other Penicillium spp. (8% of isolates), Geotrichum spp. (6%), Schizophyllum commune (4%) and yeast spp. (8%). Trichoderma, Fusarium and mucoraceous species were also present on some bales. The surface area of bales affected by fungal growth was, on average, 0.32 m2 (s.d. 0.26) or 5% as a percentage of bale surface area, although this ranged from <1% to 15%. Bales with damaged plastic wrap had greater mould coverage than bales with visibly undamaged plastic. The high incidence and diversity of fungal growth on baled silage gives cause for concern, particularly because of the prevalence of Penicillium roqueforti, a toxigenic mould. An in vitro assay for detecting resistance to Fusarium head blight and associated mycotoxins in wheat R.A. Browne and B.M. Cooke Dept. Environmental Resource Management, University College Dublin The Fusarium head blight disease complex is one of the most important diseases of cereal production world-wide causing serious mycotoxin contamination of harvested grain. Although resistance to FHB is partial and is generally accepted to be under polygenic control, resistant cultivars are seen as the most viable strategy for control of FHB and associated mycotoxin contamination. However the components of partial disease resistance (PDR) to FHB are poorly understood and consequently incorporating resistance into adapted high yielding cultivars has been hampered. A novel and rapid assay using detached leaves inoculated with conidial suspensions of Microdochium nivale, a member of the FHB disease complex, measuring the PDR components incubation period (period from inoculation to first appearance of symptoms under macroscopic examination) and latent period (period from inoculation to sporulation) was developed. Greater delays in the first appearance of symptoms (incubation period) and in sporulation (latent period) on wheat hosts in the detached leaf assay were correlated to greater FHB disease resistance (UK 2003 recommended list ratings) in Irish and UK commercial cultivars (n = 22) (rs = 0.53; P < 0.05 and rs = 0.70; P < 0.01 respectively). These findings indicate that PDR components detected in the detached leaf assay share a common genetic basis with much of the resistances to FHB expressed in the head of these wheat cultivars and could therefore be useful for pre-screening resistance to FHB. The relationship between PDR components in the detached leaf assay and exotic sources of highly effective FHB resistances is currently being investigated. Calcium and iron phosphate solubilization by ectomycorrhizal fungi Brian R. Gibson & Derek T. Mitchell Department of Botany, University College Dublin Mycorrhizal fungi are important in mediating the transfer of phosphorus to host plants. In this study the ability of ectomycorrhizal fungi (a total of 15 isolates from 8 taxa) to solubilize sparingly-soluble metal phosphates was assessed. The isolates were grown on MMN agar medium amended with calcium phosphate or iron phosphate (0.01% w/v). A clear halo (solubilization zone) appeared beneath the growing colonies. The rate of radial mycelial extension (R; m h-1) and solubilization zone extension (Rs; m h-1) were determined by measuring the colonies at intervals over a period of up to 60 d. Solubilizing ability was expressed as solubilization ratio (Rs/R). At the final harvest, dry weight (DW; mg) and P concentration of the mycelia were determined. Isolates showed lower or higher DW and R values in the presence of metal phosphate, relative to a control medium. Solubilizing ability varied, both within and between species. Of the 15 isolates, 14 and 6 were capable of solubilizing calcium phosphate and iron phosphate, respectively. R s/R values ranged from 0.3 to 2.4 for calcium phosphate and from 0.3 to 2.8 for iron phosphate. Solubilization was associated with a lowering of medium pH. It is concluded that solubilizing ability is isolate- rather than species-dependent and that solubilization is achieved by acidification of the medium. Isolates with good solubilizing ability, e.g. Paxillus involutus 07, Suillus bovinus 97 and Suillus grevillei 98, would be of particular benefit to host plants growing on soils rich in calcium or iron phosphate. Activity of arbuscular mycorrhizal fungi in an Irish grassland after long-term phosphorus fertilisation G.E. King-Salter1, N. Culleton2 & D.T. Mitchell1 1Department of Botany, University College Dublin, Dublin 4 2Environmental Research Centre, Johnstown Castle, Teagasc, Wexford Arbuscular mycorrhizal fungi (AMF) are among the most common soil microorganisms, and are important root symbionts by enhancing plant uptake of phosphorus (P). In recent decades, widespread phosphorus application has transformed Irish soils from being P-deficient to having an excess of P; it is important to examine the effect of this change in P-status on AMF. This study focusses on a 35 year-old fertiliser experiment at Johnstown Castle, Co. Wexford, in which cattlegrazed plots have received either high (30kg P ha-1yr-1), intermediate (15kg P ha-1yr-1) or zero levels of inorganic phosphate. Roots of three major grass species were collected from the experimental plots and stained to quantify levels of mycorrhizal formation. Spores were extracted from the soil by sieving and sucrose centrifugation. A growth-chamber experiment assessed the potential of the AMF communities to form mycorrhizas with Lolium perenne seedlings. In the field, P addition reduced both numbers of AMF spores in the soil and mycorrhizal colonisation of Agrostis stolonifera, Holcus lanatus, and Lolium perenne. AM colonisation in January was less than half that in August, indicating a substantial decline in mycorrhizal activity during the winter. L. perenne seedlings grown for 4 weeks in intact soil cores showed that increased soil P significantly reduced mycorrhizal formation. Six species of AMF have so far been detected in the experimental plots, in the genera Acaulospora, Glomus and Scutellospora. This study will determine whether AMF species vary in their response to P additions in Irish grasslands. The Use Of Spent Mushroom Compost As An Organic Manure And Nutrient Source On Potatoes 1,2, 1 2 J. Duggan M. J. Maher and M. J. Hennerty 1 Teagasc Kinsealy Research Centre 2 Department of Crop Science, Horticulture and Forestry, University College Dublin. The Irish mushroom industry produces over 260,000 t of spent mushroom compost (SMC) annually which must be disposed of in an environmentally friendly manner. The object of this experiment was to assess the suitability of SMC as a nutrient source in potato production by studying its effects on yield and on the uptake of some of the major plant nutrients. The experimental design was a split plot with 4 replications of 4.5 x 10.5 m plots receiving 5 rates of SMC (0, 8, 16, 32, and 64 t ha -1). Each plot was split into 3 subplots receiving 3 rates of N fertiliser (0, 75 and 150 kg N ha -1). The SMC was rotovated into the plots and potatoes cv. Records were planted. The addition of SMC (comparing means of the 0 with the 64 t ha-1 treatments) increased tuber dry weight from 5.86 to 7.88 t ha-1 (s.e.d 0.592), tuber N content from 56.6 to 81.9 kg N ha-1 (s.e.d 6.72) and tuber P content from 11.7 to 15.3 kg P ha-1 (s.e.d 1.07). The addition of fertiliser N (comparing means of the 0 with the 150 kg N ha-1 treatments) increased tuber dry weight yield from 5.01 to 7.59 t ha-1 (s.e.d 0.203), tuber N content from 41.4 to 83.6 kg N ha -1 (s.e.d 2.64) and tuber P content from 10.9 to 14.3 kg P ha-1 (s.e.d 0.418). It was concluded that SMC was a suitable nutrient source for potatoes, however in most cases it would require additional N. Targeting tree seedlings through propagation methods and outplanting performance in Northern Ireland, Falkland Islands and Tierra del Fuego R. Olave and J. McAdam Queen’s University Belfast Nowadays there is recognition that by planting trees on either grazing, forest or degraded ecological systems farmers can help reduce the current over utilisation of natural resources and satisfy long term strategic goals, while at the same time bring greater biodiversity, landscape benefits on livestock farms and rural economies. Oak (Quercus robur) and Ash (Fraxinus excelsior) in Northern Ireland; Lodgepole pine (Pinus contorta), Cypress (Cupressus macrocarpa) and Willows (Salix spp) in the Falkland Islands and Lenga (Nothofagus pumilio) and Nirre (Nothofagus antarctica) in Tierra del Fuego are potentially useful tree species which can be integrated into multifunctional land use systems but there are environmental and anthropogenic factors that limit the establishment and natural development of these trees. However the use of the most appropriate planting stock can help overcome such limitations, while site management can also accelerate seedling growth. Thus by defining propagation methods, morphological and physiological parameters in the nursery and after outplanting it is possible to adjust target seedling characteristics on a specific planting site. The aim of this research has been to investigate the integration of tree seedling production and outplanting performance for multifunctional forestry needs, where these seedlings must meet defined levels of performance which might be suitable for the specific requirements of soil, climatic and socio-economic conditions found in Northern Ireland, the Falkland Islands and the Chilean side of Tierra del Fuego. The results indicate that outplanting performance can be enhanced greatly by adjusting tree propagation methods to predetermined target tree seedling levels and then subjecting them to periods of management. Plant programmed cell death requires de novo protein synthesis Mark Diamond, Olga Rocha, Fiona Doohan and Paul F. McCabe Department of Botany, University College Dublin, Dublin 4 Programmed cell death (PCD) is an essential feature of many developmental processes in plants and animals. It is also an indispensable component of their defence response to invading pathogens. The caspase execution pathway in animals, which results in PCD, occurs without the need for protein synthesis. In plants it is not known if protein synthesis is required for PCD. Deoxynivalenol (DON) is one of the most common mycotoxins contaminating grains. The toxin is produced by the Fusarium species F. graminearum, F. nivale, and F. culmorum and has been linked to significant outbreaks of food poisonings in humans and animals. The toxin disrupts protein synthesis leading to apoptotic cell death in animals. Using an Arabidopsis cell system we examined responses to varying concentrations of DON added prior to other insults such as heat shock or hydrogen peroxide (H2O2) treatment. When added prior to treatments with H2O2 or heat shock, DON significantly decreased incidents of PCD and many cells that would normally die remained viable. 5ppm DON was the optimum concentration found to maximally reduce levels of death induced by 53C heat shock or 6M H2O2. PCD was also arrested, and many cells remained viable (30-50%), when treated with the protein synthesis inhibitor cycloheximide (CHX) prior to heat shock. The evidence points to a requirement in plant PCD for de novo protein synthesis. It appears that DON not only suppresses protein synthesis but also PCD. This suggests that PCD is a component of the plant defence response. Investigating the role of calcium in plant programmed cell death. E. M. Molony and P.F. McCabe Department of Botany, University College Dublin, Dublin 4 Programmed cell death (PCD) in plants has a specific morphology, which involves the retraction of the protoplast from the cell wall. PCD can be induced in cell suspension cultures of Arabidopsis thaliana once the cells have been subjected to a heat treatment of 55OC. We investigated whether calcium has a role in regulating programmed cell death in plant cells. One way to investigate any calcium role is by blocking calcium influx into the cell following a death-inducing stimulus – this can be achieved by using lanthanum chloride (LaCl3) a calcium channel blocker. Different concentrations of LaCl3 were added to cells 30 minutes before heat treatment. Twenty hours following heat treatment it was observed that low concentrations of LaCl3 had little effect on the cells, moderate LaCl3 concentrations inhibited PCD morphology but not death, while higher concentrations of LaCl 3 almost completely inhibited cell death. These data suggest that calcium regulates PCD morphology and when blocked from entering the cell, delays the onset of cell death from lethal heat treatment. Taxonomic comparison and phytosociological analysis of Puccinellia fasciculata, P. distans and P. maritima. K. Irvine, M. Otte and S. Waldren Department of Botany, University College Dublin Puccinellia fasciculata is a rare and protected species, occurring on only a few salt marsh sites on the East and South coasts of Ireland. In order to manage and protect sites where P. fasciculata occurs, its ecology must be understood. Its occurrence and traits were compared to P. maritima and P. distans, which also occur in Ireland. Taxonomic difficulties between the Puccinellia species cause problems in field identification. Qualitative and quantitative traits were analysed to establish a list of distinguishing traits for the three species. Traits of plants grown from seed and maintained under standardised greenhouse conditions were measured. The three species were found to be morphologically distinct. Of a total 117 traits analysed, 53 distinguished at least one of the species from the three. 17 new distinguishing traits were produced, and 14 were further defined. A phytosociological study was also carried out and confirmed that the three species belong to different syntaxa. The species were found to belong to a total of six different communities, and to inhabit distinct habitats. Preliminary examination of the species’ growth responses to increased nitrogen (0.05-5.0 mM) and phosphorous (0.05 or 0.5 mM) supply suggest that these nutrients significantly influence the distribution of the plants within the salt marsh. Results imply that P. fasciculata and P. distans are adapted to nutrient poor conditions. Elemental analyses of field material suggest differences between the species’ tolerances to the effects of waterlogging (mainly increased iron and manganese availability), which is likely to influence their distribution and abundance. Spread of human impact on the Irish vegetation: a palaeoecological perspective Robert Marchant, Fraser J.G. Mitchell Botany Department, Trinity College, Dublin Pollen data from ninety sites in Ireland have been collated within a database as part of the Irish Palaeoecological Analysis project, this provide a sensitive archive to document how vegetation has responded to environmental change over a range of spatial and temporal scales. The database is used to analyses the spread of plant taxa that have a ruderal or agricultural ecology, possibly originating from human activity. An analysis of multi-site pollen data focuses on the presence of ruderal (e.g. Rumex), agricultural (e.g. Avena, Hordeum) or secondary vegetation (e.g. Chenopodiaceae) to indicate the location, timing and spread of vegetation disturbance. To standardise the pollen data, and allow inter and intra site comparisons, this pollen sub-set are portrayed as a series of contours to demonstrate the spatial and temporal dimension to spreading vegetation disturbance. The pollen data indicate that vegetation disturbance differed considerable in different areas - although an increasingly common trait, it is influenced by site-specific phenomena, such as the proximity to oceanic influence, geology and human activities from wholesale forest clearance to low density grazing activity. Results presented from Ireland are combined with evidence for early land-use from north-western Europe. Based on this supra-regional study, possible inter-dependencies between environmental and cultural change, and problems of linking findings derived from different disciplines of natural science are discussed. Estimating speciation and extinction rates from phylogenetic trees: an Markov chain Monte Carlo approach Nicolas Salamin Botany Department, Trinity College, Dublin Phylogenetic trees based on molecular data contain a temporal dimension associated with the branch lengths defining the trees. The tempo of evolution of lineages can then be estimated from those trees using stochastic processes, such as the birth and death process, resulting in estimates of speciation and extinction rates. Here, a full maximum-likelihood approach was used to estimate the speciation and extinction rates, and the uncertainty in the phylogenetic reconstruction was factored out using Markov chain Monte Carlo. No prior distribution was assumed on the parameters, and an importance sampling scheme was used instead. Computer simulations showed that accurate estimates of speciation and extinction rates can be obtained using this method, as long as large DNA matrices and a comprehensive set of taxa have been sampled. Finally, the Gesneriaceae, a tropical plant family with multiple pollination syndromes, was used to illustrate the use of the method. Large phylogenetic trees of the grass family: a multigene approach Trevor R Hodkinson, Nicolas Salamin, Vincent Savolainen, Michelle van de Bank, Steve Renvoize, Mark W Chase Botany Department, Trinity College, Dublin Higher level phylogenetic studies of grasses have utilized DNA sequences from a number of gene regions from plastid (cpDNA restriction sites, atpB, matK, ndhF, rbcL, rpoC2, rpl16, trnL-F), nuclear (ITS, phyB, GBSSI) and mitochondrial (phyA) genomes. However, relatively few studies have used multi-gene analyses. These studies have included representatives from all commonly recognized subfamilies and have reviewed taxonomic groupings such as subfamilies and tribes and helped assess a number of macro-evolutionary hypotheses. The largest analyses including the GPWG (presented at the Monocots II - Grasses III, Symposia, Sydney, 1998) have sampled the tribes less thoroughly, used a relatively small number of taxa (mostly less than 100), and included less than 10% of the genera. A considerable level of incongruence also exists between datasets regarding the sister group of the grasses, the delimitation of major clades and their inter-relationships. We present multigene analyses combining the plastid trnL intron, trnL-F intergenic spacer and rbcL gene that include over 200 taxa. The results are presented in relation to systems of classification and other phylogenetic studies. The relative merits of multi-gene and supertree approaches for producing comprehensive phylogenetic trees within the family are also discussed. We ask ‘How far are systematists from complete generic and species level phylogenetic trees of the grass family?’ Biogeography, phylogeny and evolutionary radiation in the red algal tribe Ceramieae Lynne McIvor, Chloe Evans and Christine Maggs School of Biology and Biochemistry, Queen’s University Belfast The cosmopolitan red algal tribe Ceramieae (Ceramiaceae, Rhodophyta) currently contains at least nine genera and over 200 species, and are readily identifiable by their distinctive nodal development of corticating cells. However the Ceramieae is currently in a state of taxonomic confusion. In order to resolve taxonomic and evolutionary relationships within the Ceramieae, rbcL sequence data was obtained from over 50 taxa, including all the known species of Ceramium and Microcladia from the British Isles. Phylogenetic analysis revealed that Centroceras, Coralophilla and Ceramium flaccidum constitute separate evolutionary lineages that are placed basally within the Ceramieae. Results from this study indicate that, as currently constituted, the genera Ceramium, Microcladia, Campylaephora, Herpochondria, Reinboldiella and Carpoblepharis do not represent distinct genera, and the species currently placed within these genera are distributed between a number of clades which form two broad biogeographical groups: a North Atlantic/Mediterranean clade; and a Pacific/Southern Hemisphere clade. Within these large groups of species, much morphological homoplasies and/or character reversals have occurred, suggesting a rapid radiation within the Ceramieae. Pollen Mediated Gene flow in Ryegrass Eimear Ryan, Conor Meade, Ewen Mullins, James Bourke, Martin Downes Gene Flow Laboratory, Institute of Bioengineering and Agroecology, NUI Maynooth Ryegrass is the most important forage crop in Ireland, covering c. 93% of all arable land. With the advent of GM technology, there is a need for the understanding of underlying rates of gene flow within and between populations of ryegrasses. This project will assess rates of pollen-mediated gene flow from Lolium multiflorum (Italian ryegrass) to Lolium perenne (Perennial ryegrass) in a field situation. A selection of morphological traits and molecular markers (AFLP and microsatellite) were identified and a pilot field study was carried out in the summer of 2003. Gene flow was successfully identified using these methods. Larger scale field trials are being conducted in 2004 where the same hybrid identification procedure will be used. Innate zinc tolerance in Glyceria fluitans, an investigation using hydroponic experiments, protoplast analysis and AFLP fingerprinting David J. Matthews, Paul F. McCabe, Thomas F. Gallagher and Marinus L. Otte Department of Botany, University College Dublin Traditionally metal tolerance in plants has been thought to evolve following exposure to elevated metal levels in the soil. However, there are examples of species that are innately metal tolerant, without apparent exposure to metals. The wetland grass Glyceria fluitans is such an example. Five populations of G. fluitans from Ireland, England, Denmark and Poland were investigated for tolerance, by growing them hydroponically in zinc-amended nutrient solutions. Growth parameters such as leaf and root length, biomass, zinc uptake into plant parts were measured to determine tolerance between the different populations. Protoplasts were isolated from live leaves to investigate the distribution of cellular zinc. This was to determine if zinc was being sequestered within the protoplasts or bound to the cell wall. All populations possessed innate tolerance to zinc. Uptake of zinc did differ between populations, but this did not affect tolerance. Some populations sequestered more zinc in their roots and other populations sequestered more zinc in their leaves. The concentrations of zinc within the protoplasts increased with increasing zinc treatment, but the amounts of zinc in the cell walls did not. These five populations, along with five additional populations were then investigated genetically using Amplified Fragment Length Polymorphism (ALFP) technique, using six different primer combinations. This technique can detect differences both within and between populations and so reveal the degree of variation in G. fluitans. Information will be derived about population structure in Europe and whether plants that take up zinc differently belong to distinct populations. Breeding system of invasive Rhododendron ponticum in Ireland Jane C. Stout Botany Department, Trinity College, Dublin Rhododendron ponticum is a highly invasive exotic species which spreads in suitable habitats by producing many tiny, wind-dispersed seeds. Experiments were carried out in a wild population of R. ponticum in Co. Dublin to test a) whether flowers were capable of autogamous seed production, b) whether seed production increased with outcrossing, c) the importance of self-flower pollen in fruit and seed set, and d) whether plants were pollinator limited. Seed production was greatly reduced when pollinators were artificially excluded from visiting flowers, and increased with artificial outbreeding. There was no significant impact of emasculation (removing anthers) on fruit or seed production, suggesting that self-pollen is not of much importance. There was no evidence of pollination limitation in the population studied, although previous observations have indicated this may occur in other populations in Ireland. Germination experiments have been conducted to determine whether inbreeding has any negative impact on germination success. These results will be discussed in the context of the role of pollination mutualisms in exotic plant invasion. Transcription of the succinate dehydrogenase subunit 4 (sdh4) gene in A.majus: RNA editing and co-transcription with cytochrome oxidase subunit 3 (cox3) gene. Beverley Henley Plant Cell Biology Lab, National University of Ireland, Maynooth In this work Southern hybridisations were used to examine mitochondrial gene content in the mitochondrion and nucleus of Antirrhinum majus for most known mitochondrial genes. This investigation shows that the sdh4 gene is located in the mitochondrion. The analysis also shows that the cox3 gene is present in the same mitochondrial genomic region. Cloning and sequencing of the 2kb Sal1 sdh4 homologous mt. DNA fragment, indicated a 368-bp fragment showing 98% sequence similarities to the sdh4 mt. DNA in Solanum tuberosum and the presence of the cox3 gene sequence immediately upstream from the sdh4 gene. This fragment was sequenced: it contained the full cox3sdh4 DNA sequence. Northern hybridisations and RT-PCR analyses indicate that cox3 and sdh4 are co-transcribed, generating a complex transcription pattern. The sdh4 cDNA products were then cloned and will be sequenced. The genomic sequence and cDNA sequences will be compared. This will indicate the extent of RNA editing in the sdh4 transcript. The cDNA sequence will also be compared to sdh4 cDNA sequences in other Angiosperm species to investigate whether the RNA editing sites are conserved between the species or whether they are species specific. A Model for the Study of Calcium Fluxes in Plant Cells Noreen Curran, Eugene Kane, and Philip Dix Plant Cell Biology Lab, National University of Ireland, Maynooth There are several important roles for calcium in higher plant chloroplasts. These include influencing expression of photosynthesis associated plastid encoded genes and in the assembly and function of the oxygen evolving complex of thylakoids. Calcium also regulates the function of several proteins including stromal chaperones important in assembly of rubisco. Plant cells maintain a low free cytosolic calcium content, while in the chloroplast, the free stromal calcium is much higher. It is also known that there are different levels of calcium within the chloroplast. Transient increases in response to different stresses have been documented. However, no methods for accurately measuring calcium fluxes within plant cells have been devised. This project aims to use a novel approach to elucidate the role of fluxes of free calcium in chloroplasts in response to environmental stresses. We aim to express a gene for a calcium sensitive fluorescent protein (cameleon), in the chloroplast of plants with macrochloroplasts (one to six giant chloroplasts per cell). Cameleon will be targeted to the chloroplast stroma and the thylakoid lumen. These plant cells will be a model for studies at the single cell and organelle level on calcium fluxes into and within the chloroplast in response to various stimuli and provide more detailed information on organelle calcium fluxes in plants. flubber (flb), a new root hair mutant in Arabidopsis thaliana Amanda Doran and Martin Steer Department of Botany, University College Dublin Understanding the genetic programme behind the development of a specific cell of an organism will allow us to ultimately manipulate and change the way in which an organism is formed. This project is concerned with understanding the genetic programme that controls root hair formation and development. The sequence of events that leads to the growth of a root hair in Arabidopsis thaliana is precisely regulated. We carried out a screen and identified a new true breeding mutant called flubber. The flubber (flb) mutant had abnormally short root hairs which showed branching along their length. Other cell types were also affected in flb plants. flb plants had smaller rosette diameters, shorter inflorescence stems, smaller siliques, increased numbers of trichomes and a reduced number of stomata. It is thought that the cell elongation process is affected in flb plants. A defect in polarity would account for the branching that is evident along the root hair. Crossing this mutant with all other known root hair mutants established that the FLB gene acts during the main elongation phase of the root hair development. Mapping of the FLB gene and characterisation of gene products will allow the exact function of FLB to be determined. Improving the micropropagation of selected mature Irish ash (Fraxinus excelsior L.) Jane I. E. Abbott1,2, Gerry C. Douglas1 and Trevor R. Hodkinson2 1 Teagasc Kinsealy Research Centre, Malahide Road, Dublin 17. 2 University of Dublin, Trinity College, Dublin Ash (Fraxinus excelsior L.) is a native hardwood species in Ireland valuable as a fast growing tree well adapted to agricultural sites. It produces wood valued for its toughness and elasticity. A key objective for genetic improvement of ash is to develop means to vegetatively propagate selected mature trees. In the mature phase most forest species are recalcitrant to vegetative propagation and tissue culture methods offer a way around this obstacle. Micropropagation experiments with selected genotypes of ash focused on identifying the optimum culture regime, media salt composition and carbohydrate source for in vitro culture. Explants cultured alternatively on Murashige and Skoog (MS) media with BAP (5mg/l), TDZ (0.55mg/l) and IBA (0.2mg/l) and QRC media with no hormones and 3g/l activated charcoal had the highest propagation rate (1.92) and the healthiest appearance compared to explants cultured on either media continuously (propagation rate of 1.83 for MS and 1.63 for QRC media). Explants cultured on Ruigini Olive medium (OM) had the highest propagation rate (3.07), mean shoot length (7.46 mm) and average dry weight increase (17.22 mg) compared to those cultured on MS, Woody Plant Medium (WPM) or Driver and Kuniyuki Walnut medium (DKW). In October 2003 shoots cultured on MS media containing 87.6mM sucrose had the highest propagation rate (1.57) compared to shoots cultured on equimolar concentrations of mannitol, glucose and an equal mixture of sucrose and mannitol. However, in March 2004 the highest propagation rate was from explants on the mixture of sucrose and mannitol (2.0). The effects of sucrose concentration and sodium chloride on callus formation and somatic embryogenesis of an F1 cucumber hybrid Khaled M. Suliman Elmeer and Michael J. Hennerty Department of Crop Science, Horticulture and Forestry, University College Dublin The objective of this experiment was to investigate the effects of sucrose concentration and sodium chloride on callus formation and somatic embryogenesis of an F1 cucumber hybrid. F1 hybrid seeds of cucumber cv. Profito were surface sterilized and germinated in vitro. Explants were taken from the leaves of planlets and placed on induction medium for three weeks. Callus weights were taken at the end of this stage. Callused explants were transferred for three weeks to maturation medium with three concentrations of sucrose (30, 60 and 90gl-1) and two concentrations of sodium chloride (0.0, 10.0mM). Callus weights were taken in the end of this stage, and then callused explants were subcultured onto growth regulator-free medium and placed in the light at room temperature for observation of embryogenesis. There was no significant difference between the three levels of sucrose on the weight of callus at the end of the induction phase. At the end of the maturation phase, the sodium chloride alone and the interaction of sucrose concentration with sodium chloride had no significant effects on the weight of callus, while the sucrose concentrations alone significantly affected the weight of callus. The 30gl-1 sucrose concentration yielded the highest callus weight of 525.3mg, with the 90gl-1 sucrose concentration giving 281.9mg, the lowest recorded weight. The greatest somatic embryo number (10) was obtained in the treatment of 90gl-1 sucrose without sodium chloride. The treatment 60gl-1 sucrose with sodium chloride give 2.4 embryos per replicate, which were the lowest recorded result. Genetic transformation of apple with a pathogenesis-related barley peroxidase gene and its effects on stress responses and development. Deborah V. Vicuna, Renee Malone, Philip J. Dix. Biology Department, NUI Maynooth Peroxidases are enzymes found throughout the plant kingdom. They are involved in many processes including lignification, auxin oxidation and responses to biotic and abiotic stress. In order to study the effect of increased peroxidases activity, we have introduced a pathogenesis-related cell-wall peroxidase from barley into the genome of apple (Malus domestica var. Greensleeves) via Agrobacterium-mediated transformation. Apple, a woody crop, has been chosen as a model tree species. Transgenic plants were identified by PCR and southern analyses. Levels of peroxidase activity in the transgenic plants were analyzed. Transverse sections of the plants stems were stained in order to study xylem patterns. Also, plants were tested for increased tolerance to heat stress. Plants containing the cell-wall peroxidase showed up to 4.5-fold increases in levels of peroxidase activity. Xylem staining showed a change in xylem vessel patterns of the transgenic apple plants when compared to the wild type. Leaf discs from plants overexpressing the cell-wall peroxidase were subjected to high temperatures and the conductivity of the suspension media was measured. Electrolyte leakage from the transgenic leaves was lower when compared to the wild type. These results indicate that changes in peroxidase activity might increase the level of resistance to abiotic stresses such as heat and also play an important role in the development of the plant. Poster Abstracts Effect of 1-methycyclopropene on five varieties of apples in refrigerated and controled atmosphere storage. Fatma Ageli and Micheal J. Hennerty Dept of Crop Science , Horticulture and Forestry . UCD Five cultivars of apple: Jonagold, Greensleeves, Golden Delicious, Karmijn de Sonnaville and Elstar, were treated with the ethane (ethylene) inhibitor gas 1-methylcyclopropene (1-MCP, Smart Fresh) at a concentration of 626 ppb for 24 hours. The treatment was carried out in gas-tight container of 1m 3 equipped with a fan inside to achieve maximum penetration. After 24 hours A gas- tight container all the fruits were placed in either refrigerated storage or controlled atmosphere (CA) storage. Fruit samples, for testing, were removed from the refrigerated storage two weeks after harvest and, subsequently, at two weekly intervals. Testing was done after holding the fruits for 7 days at 20C o. The parameters measured were: pressure (kg /cm 2), soluble solids (% TSS), acidity as malic acid (gl 1), % starch, % tannins and colour. CA storage –ended on 29/2/ 04. Testing of theses fruits were the same as for fruits in refrigerated storage. The preliminary results indicated that 1-MCP efficacy was affected by cultivar and storage conditions. Some of the 1-MCP treated cultivars stored in a cold room maintained higher firmness and titratable acidity for 5 months storage, compared to untreated fruits. Jonagold, treated with 1-MCP had a firmness reading of 7.3 kg after 5 months refrigerated storage which was the same reading as at harvest. Karmijn and Elastr treated with 1-MCP maintained their firmness at 7.2 and 6.9 kg, respectively. Greensleeves’ firmness was 3.5 kg after 5 months of storage, half of that at harvest. Soluble solids in treated apple fruits were higher or equal to the total soluble solids at harvest. Effects of 1-MCP on tannins depended on cultivar treated. Generally, CA stored fruits had enhanced performance with 1-MCP treatment. Suppression of Programmed Cell Death in Arabidopsis Cell Cultures by Sphingosine-1Phosphate K. P. Alden and P.F. McCabe Department of Botany, University College Dublin Programmed Cell Death (PCD) involves a series of events in which the cell directs its own demise. It depends upon the active participation of the dying cell and is gene regulated. PCD is believed to be essential for normal plant development e.g., xylogenesis, embryogenesis, and senescence. It also plays a key role in plant defence responses to invading pathogens as a part of the hypersensitive response. However, very little is known about the regulation of PCD in plants. Sphingolipids are ubiquitous constituents of eukaryotic cells. They have been investigated in mammals and yeasts for decades, where it has been shown that they act as second messengers and can regulate cellular homeostasis. Recent research suggests that the relative levels of two sphingolipid metabolites, Sphingosine-1-Phosphate (S-1-P) and Ceramide, are important factors in determining whether mammalian cells live or die. Evidence from a number of experiments has indicated a possible role for S-1-P in plant PCD. Cells from suspension cultures of Arabidopsis thaliana undergo PCD when cultured at low density due to a lack of survival signals. The addition of S-1-P to such low-density cultures can block this cell death. In addition, S-1-P is also shown to have a protective effect against severe abiotic stress. When subjected to a 55C heat shock for ten minutes approximately 80% of Arabidopsis cells die by PCD. The addition of S-1-P can completely inhibit this cell death. These results suggest that S-1-P may have a fundamental role in plant PCD. Genotype-dependent accumulation of Triticum aestivum transcripts in response to deoxynivalenol Khairul I. Ansari1, Sarah Kessans2, Damian Egan1 and Fiona M. Doohan1 1Department of Environmental Resource Management, University College Dublin 2Current address: Botany and Plant Pathology, Lilly Hall, Purdue University, 915 West State Street, West Lafayette, IN 47907-2054, USA. Deoxynivalenol (DON) is a trichothecene mycotoxin produced by cereal-pathogenic Fusaria and evidence suggests that it acts as a phytotoxic disease virulence factor aiding host pathogenesis. The effect of DON (20 ppm) on gene expression in roots of Fusarium head blight (FHB) disease resistant (Frontana and CM 82036) and susceptible (Remus and Riband) wheat (Triticum aestivum) cultivars was determined (24-h post-treatment). Despite inhibition of protein synthesis being the mode of action of this toxin, at least 70 transcripts were overexpressed in the wheat roots of different cultivars in response to DON. We assessed the effect of DON over time, on the production of specific transcripts including translation elongation factor 1 (EF-1), adenosine kinase (ADK), retrotransposon-like homologs and genes of unknown function. We describe the genotype and treatment-specificity of transcript accumulation over time and consider the potential implications on the host cell response to trichothecenes and trichothecene-producing Fusaria. Large trees, supertrees and the grass phylogeny: a high performance computing approach Yanis Bouchenak-Khelladi, Nicolas Salamin, Vincent Savolainen, James Sexton, Trevor R Hodkinson Botany Department, Trinity College, Dublin Grasses (Poaceae) are one of the largest families of higher plant and are undoubtedly the most important from an economic perspective. They represent four of the world’s top five crops, cover huge areas of land as forage for dairy and meat industries, and provide raw materials for the building, paper and cellulose industries. This project aims to produce large multigene phylogenetic trees for over 500 species and use new meta-analysis tools to piece together existing phylogenies into supertrees that contain all of the commonly recognised species within the grass family (c.10,000 species). Resulting trees will be used for phylogenomic and systematic purposes (Soltis & Soltis, 2001). The project will also aim to answer important taxonomic questions such as how the major groups of grasses and cereals relate to one another. UV-B gene expression in Mycelis muralis Brady A. and Gallagher T.F. Department of Botany, University College Dublin Plants respond to elevated UV by inducing the expression of a range of genes including those for flavanoid biosynthesis. These flavonoids are UV absorptive pigments and provide protection from the damages caused by UV radiation in plants. We have been looking at the response of Mycelis muralis genotypes from high and low light environments to UV light regimes. These genotypes form distinct populations, (Kavanagh 2000). Plants from both populations respond normally to elevated UV-A/bluelight treatments by increasing the expression of genes for flavonoid biosynthesis, in contrast only plants from the high-light environment were capable of responding to elevated UV-B. Our current hypothesis is that failure of the low-light population to respond to UV-B is due to defects in either UVB perception or UV-B signal transduction. The receptor and signaling pathway for UV-B responses in plants remains to be elucidated. The availability of the Mycelis genotypes provides a unique tool to address this problem. Our aim is to characterise the molecular differences between the two genotypes. Rapid subtractive Hybridisations (RaSH) were carried out on cDNAs from UV-B treated high-light genotypes. To date 97 clones have been generated from the subtraction of high-light UV-B (24 hour) vs. low-light UV-B (24 hour), and 72 clones from high-light UV-B (24 hour) vs. high-light White light (24 hour). These clones were grouped according to insert size, this resulted in 35 clones and 12 clones respectively. It is hypothesised that amongst these clones will be the genes involved in UV-B perception and/or signal transduction in Mycelis muralis. Analysis of intra and inter-specific genetic evolution of European wheat-pathogenic Fusarium species J.M. Brennan, D. Egan and F.M. Doohan Department of Environmental Resource Management, Agriculture and Food Science Building, University College Dublin Using PCR-RFLP and AFLP analyses, we examined the inter- and intra-specific genetic diversity of 80 Fusarium wheat-pathogenic isolates representing five species (F. avenaceum, F. culmorum, F. graminearum, F. poae and M. nivale) and originating from Ireland, the UK, Hungary and Italy. At the intra-specific level, UPGMA cluster analysis of AFLP data revealed that the F. poae isolates showed the highest level of genetic similarity (s 0.64), closely followed by the F. culmorum isolates (s 0.63). The most genetically diverse species was F. avenaceum (s = 0.10-0.79). PCR-RFLP analysis confirmed these results in that F. avenaceum was the most genetically distinct species (s = 0.11-0.9), and showed very low similarity to the other species (s = 0.11-0.44). Principal coordinate analysis of AFLP and PCR-RFLP generally confirmed the UPGMA clustering profiles. The present study also found a relationship between intra-species genetic diversity and country of origin of the isolates; no relationship was found between genetic diversity and either growth or pathogenicity of the isolates. The relations between epiphyte diversity and plantation forest structure and composition Linda Coote, Daniel L. Kelly, Paul Dowding Department of Botany, Trinity College Dublin Government policy aims to increase the area under forest in Ireland to 17% by 2030 (Department of Agriculture, Food and Forestry, 1996). At present, however, there is little information on biodiversity in plantation forests in Ireland. Epiphytes form an important component of Irish woodland biodiversity (Kelly, 2000) and, since the ground flora of plantation forests is not diverse, they may be even more important in these forests. This research is being carried out as part of the BIOFOREST project, a COFORD/EPA funded 5-year project on forest biodiversity. Work to date has focused on Sitka spruce (Picea sitchensis) plantations, which make up more than 50% of the forest estate. Trees were studied in the forest interior and at the edges of glades at 12 sites in the Cork and Wicklow areas. Epiphytes were recorded in plots on the trunk and branches at different heights in the tree, using tree-climbing techniques. Results to date indicate an epiphytic flora of ca. 58 lichen and 35 bryophyte (13 liverwort and 22 moss) species. The average site species richness was 29 with the average species richness for the Wicklow sites 25 and for the Cork sites 33. Future work will focus on larch (Larix spp./hybrids) stands in order to offer a comparison with Sitka spruce. The epiphyte flora of over-mature Sitka spruce and larch stands will also be studied in order to assess how the diversity of epiphytes is enhanced at sites where trees have been left beyond economic maturity. Co-culture of F1 cucumber hybrids in liquid medium Khaled M. Suliman Elmeer and Michael J. Hennerty Department of Crop Science, Horticulture and Forestry, University College Dublin The experiment was undertaken to study the effect of one cultivar on another on callus formation in liquid medium. F1 hybrid seeds of cucumber cvs. Profito and Mascot were surface sterilized and germinated in vitro. Explants were taken from the leaves of plantlets and placed in induction medium, which was M&S supplemented with 2.0mgl-1 2,4-D, 0.5mgl-1 kinetin, no gelling agent and 3% sucrose; pH was adjusted to 5.82 before autoclaving at 120°C for 20min. Two explants from cv. Profito with two from cv. Mascot were inoculated into 5cm petri-dishes divided into four parts by partitions with holes to let the media pass through. Controls had only one cultivar per petri dish. Callus weights were taken at the end of this stage. The cultivars had significantly different callus weights in liquid medium after 21 days. The Mascot explants when cultured in the liquid medium alone gave a mean weight of 160.2mg callus, while when cultured with Profito explants in the same medium they gave a mean weight of 225.5mg callus, on increase of 40%. When Profito explants were cultured in the liquid medium alone they had a mean weight of 257.2mg callus, while when cultured in the same medium with Mascot explants, they gave a mean weight of 230.3mg callus, which was a decrease of 10%. It is concluded that one cultivar can influence the performance of another when they are co-cultured in a single medium. Schizophyllum commune basidiospores in the Irish air spora C. O’Gorman1, K. Brady1, 2 and H. Fuller1 1Department of Botany, University College Dublin 2Teagasc, Crops Research Centre Schizophyllum commune is a saprotrophic basidiomycete fungus, typically found on woody substrates. It was first recorded on big-bale grass in Ireland in 1990 and is now of widespread occurrence on this substratum, resulting in considerable loss of feedstuff. Previous investigations have failed to find the source of Schizophyllum contamination of bales. The fungus is rarely seen in nature in Ireland, it has not been found in soil or on grassland plants, nor has it been detected in air using conventional methods and media. In this study monokaryotic Schizophyllum cultures were used to detect Schizophyllum basidiospores in air. Airborne spores, sexually compatible with a monokaryon culture should lead to dikaryotization and thence to the formation of clamp connections and to differentiation of basidiocarps. Monokaryotic mycelia of S. commune of different geographic origins were exposed to air at Belfield, Dublin, in three ways: (i) monokaryon cultures exposed for 2 minutes in a Burkard air sampler (ii) monokaryon cultures exposed for 24 hours and (iii) wood blocks inoculated with monokaryons exposed for 7 days. Exposed monokaryon plates and wood cultures were incubated for 7 weeks and then examined for evidence of dikaryotization. Clamp connections were observed on 18/30 of the 24-hour cultures, 31/35 of the Burkard cultures and on 50/50 of the wood blocks. Basidiocarps also formed on some of the exposed monokaryon plates. The study showed that there are Schizophyllum basidiospores in the Irish air spora and it is proposed that these are the source of contamination of big-bale silage. The impact of Invasive plant species on biodiversity. The role of the soil seed bank. Gioria Margherita, Osborne Bruce Department of Botany, University College Dublin The invasion of ecosystems by alien plant species is considered one of the major threats to biodiversity. Among their many effects, invasive species may displace native species, alter ecosystem processes including hydrological cycles and fire regimes, change the nutrient status of the soil, and alter sedimentation processes. There is also the potential for hybridisation between native and nonnative species. Alien species are now a significant component of the flora of Ireland, with approximately 920 alien taxa recorded, nearly as many as the native taxa, many of which have become invaders or are potentially invasive. However, the full impact of invasive species is still poorly understood and, up to now, little attention has been given to their effects on the soil seed bank. The study of soil seed banks is important in invasion ecology because the accumulation of viable seeds in a locality could be one of the most important traits responsible for the persistence of invasive species. Secondly, soil seed banks are a potential source of seeds for the restoration of ecosystems after removal of invasive plants. The proposed study will be primarily focused on the soil seed banks associated with four invasive herbaceous species in Ireland: Heracleum mantegazzianum, Fallopia japonica, Gunnera tinctoria and Lysimachia punctata. In order to provide a time-dependent assessment of any alterations in the soil seed banks associated with these species, pollen analysis and sediment dating using 210Pb and 137Cs analysis will also be conducted. Seawater: tolerance or requirement? PAM-fluorescence in 4 maritime lichens in response to osmotic stress. John Kelly and Dagmar B Stengel Department of Botany, Martin Ryan Institute, National University of Ireland, Galway Maritime and marine lichens can locally dominate the flora of midlittoral and supralittoral rocky shores of Britain and Ireland. Although their distribution has been well documented, little is known about their responses to daily emersion and submersion in seawater, and in contrast to extensive studies on terrestrial lichens, their physiology has so far received little attention. Here fluorescence responses of Ramalina siliquosa (fructicose; supralittoral zone), Ochrolechia parella (crustose; supralittoral zone), Verrucaria maura (crustose; upper littoral- splash zone) and Verrucaria mucosa (crustose; mid-low intertidal) were compared during prolonged submersion in the laboratory. Samples were collected from different shore levels at Spiddal, Co. Galway, during autumn and winter 2003/4. Cleaned samples were initially dehydrated for 24 hours in controlled temperature rooms (R.H. 30-40%) , and the recovery of fluorescence upon submergence in either seawater or distilled water monitored using pulse sequences measured by a PAM-2000 Chlorophyll Fluorometer. Experiments were conducted at 10 and 20˚C and fluorescence yield and non-photochemical quenching were monitored in 2 min intervals. No fluorescence was detected in any species after dehdration for 24h at either temperature. Both the recovery of yields and decreases in qN varied between species. Long-term reponses were similar in both seawater and distilled water, but were strongly temperature dependent. Biological control potential of bacteria to control Fusarium diseases of cereals Khan, M. R., Fischer, S., Egan, D. and Doohan, F. M. ERM Department, Faculty of Agriculture, University College Dublin Fusarium species, including Fusarium culmorum, F. graminearum and F. poae, cause seedling blight, foot rot and head blight disease of cereals, resulting in yield loss. Additionally, head blight may result in Fusarium mycotoxin contamination of grain products. Chemical control of these diseases is, at best, inconsistent, and thus we are evaluating the potential of microbes to combat these diseases. One hundred and fifty Irish bacterial isolates were collected from Irish cereal rhizospheres and phyllospheres and in vitro dual culture and in vitro and in vivo seedling blight tests were used to determine if any such organisms showed potential for F. culmorum, F. graminearum and F. poae growth inhibition and Fusarium seedling blight disease control. In the dual culture test, 10 bacterial isolates were antagonistic to all three Fusarium species. Of these 10 bacterial isolates, Pseudomonas fluorescens KSB90 and Pseudomonas fluorescens KSB156 and 13 other bacteria that did not directly inhibit the growth of Fusarium species in dual culture tests reduced F. culmorum infection on germinating wheat (cv. GK-Othalom) seeds, as determined using an in vitro seedling blight test. Of the 15 bacteria that inhibited Fusarium infection on germinating wheat cv., 7 were nonhost cultivar-specific, i.e. they inhibited Fusarium seedling blight disease on all wheat cultivars tested (cvs Access, Marshal, Claire, Soisson and Baldus). In vivo seedling blight tests showed that Pseudomonas sp. KSB158 reduced F. culmorum infection of wheat and barley stem bases by 79% and 82%, respectively, relative to Fusarium-infected control seedlings. Turlough soils-spatial and temporal fluxes in plant nutrients Sarah Kimberley and Steve Waldren Department of Botany, Trinity College Dublin Turlough basins are biologically diverse grassland depressions in karst areas, periodically inundated in response to the local groundwater system and lacking a surface outflow. Ireland possesses the greatest global density of these habitats and their restricted range and biological interest has led to their designation as priority habitats under the EU Habitats Directive. This project aims to combat the current paucity of information with regard to the nutrient dynamics of hydrologically linked turloughs within two different catchment systems, and aims to link the changes in nutrient status within basins and between basins to vegetation changes and flooding regime. Soils are currently being described chemically and morphologically from eight turlough basins, four located in the Gort/Garryland complex, Co. Galway and four located in the Burren Lowlands, Co. Clare. Results to date indicate that there is significant plant nutrient variation along the flooding gradient within basins and that there is high degree of variation between basins with different topographical characteristics. Seasonal nutrient fluxes will be monitored in both soil and vegetation samples over the next two growing seasons and attempts shall be made to identify suitable plant bio-indicators of soil nutrient status within Turlough basins. The information gained from this project shall be used to formulate the most appropriate management plans for these habitats. The Biogeography and Conservation Biology of Spiranthes romanzoffiana Darach Lupton School of Botany, University of Dublin Spiranthes romanzoffiana is a rare and potentially threatened native orchid, recently recorded from ten 10-km squares in the Irish Republic (Curtis & Mc Gough, 1988; Preston et al., 2002). Elsewhere in Europe the species occurs in Northern Ireland, the Hebridean Islands, and at a single location in Devon, England (Preston et al 2002). The species is thus very highly localised in northwest Europe; despite being widespread throughout much of North America and Canada. Given the restricted distribution of S. romanzoffiana in Europe, Ireland has an international obligation to protect this species. Unfortunately, much needed conservation information about the species is lacking. The ecological requirements have not been documented in Ireland, and this will hamper any future conservation actions. No information exists about population genetic structure or reproductive biology of Irish populations. It is clear that important data in these areas are urgently required if S. romanzoffiana is to be successfully conserved in Ireland. The primary aim of this research is to improve the conservation knowledge of S. romanzoffiana, by providing a better baseline from which to conduct future monitoring. A number of sites throughout Ireland are being surveyed to determine habitat preferences of Irish populations. Examination of the pollination and reproductive biology is being carried out in the field and will continue throughout 2004 and 2005. Assessment of the genetic diversity within and between Irish, Scottish and North American populations is underway. It is hoped that the genetic information will reveal clues as to the origin and apparent restricted distribution of Spiranthes romanzoffiana in Ireland. Cu, Fe and Mn concentrations in three brown macroalgae from Galway Bay, Ireland: spatial, intra- and interspecific variation Helen A. McGrath, Liam Morrison and Dagmar B. Stengel Department of Botany, Martin Ryan Institute, National University of Ireland, Galway Metal concentrations in plants of Ascophyllum nodosum (L.) Le Jolis, Fucus vesiculosus (L.) and Laminaria digitata (Hudson) J.V. Lamouroux were determined using Flame Atomic Absorption Spectrophotometry. Different-aged thallus parts of A. nodosum and F. vesiculosus were analysed for Cu and Fe, and sections of L. digitata for Cu, Fe and Mn. The two fucoid species were collected from a near-pristine site in Ballyconneely (Connemara) and from Galway Docks in October 2003, while L. digitata was collected from Spiddal, Co. Galway, in February 2004. Except for Cu in F. vesiculosus from Galway Docks, metal concentrations in the two fucoids increased significantly with increasing tissue age. Within sites, concentrations in the two species were similar, but both Cu and Fe concentrations were about 10-fold higher in plants from Galway Docks than in those from Ballyconneely. Fe concentrations ranged from 18 to 197 µg gD.W.-1, and Cu concentrations from 0.77 µg gD.W.-1. Whole plants of L. digitata were divided into holdfast, stipe, meristematic and young and old frond sections. Stipes contained lowest Fe, Cu and Mn concentrations. Both Fe and Mn concentrations were highest in holdfasts, and in frond sections, increased with tissue age. Cu concentrations were highest in meristematic and young thallus parts. The range of Cu and Fe concentrations was similar to those in fucoids from Ballyconneely. To account for seasonal variation in concentrations in algal tissue, young, actively growing thallus tips of A. nodosum were collected on a bi-weekly basis between October 2003 and February 2004 from Spiddal. While tissue Cu concentrations decreased during this period, Fe concentrations increased significantly. Fe concentrations ranged from 32-82 µg gD.W.-1, while Cu concentrations varied between 0.6-1.2 µg gD.W.-1. Disease epidemiology of Fusarium Head Blight in Ireland: influence of climatic factors on the incidence of FHB and mycotoxin in wheat during 2001 and 2002. S. Monaghan, A. vanMaanen, G. Leonard, J. Brennan, F. Doohan and B. M. Cooke Department of Environmental Resource Management, Faculty of Agriculture, University College Dublin Fusarium head blight (FHB) is a worldwide disease in cereal crops, causing significant yield losses, grain quality reductions, and the production and accumulation of mycotoxins in the grain. The objective of this work was to analyse the influence of climatic factors on the incidence of FHB, the Fusarium species involved, and the mycotoxin content in wheat across Ireland during 2001 and 2002. Field sites were selected each year. Two hundred ears of winter wheat were collected randomly at each site at mid-anthesis, milky-ripe stage and at harvest. Visual disease incidence, FHB species and mycotoxin analysis were completed. Temperature, relative humidity (RH), leaf wetness (LW) and rainfall were recorded at each site from early June (mid-anthesis) to the end of August (harvest). Results showed that FHB was present throughout Ireland. Neither the sample incidence nor the average head incidence was significantly different between 2001 and 2002 indicating that overall disease incidence in the country did not change. Species-specific PCR showed that, across the sites, five Fusarium species were detected, but the relative abundance of each species varied dramatically. In 2001, F. culmorum was the predominant species and M. nivale was the least, whereas M. nivale was the predominant species detected in 2002. In 2001, deoxynivalenol was present in all sites; zearalenone was detected at 11 out of the 12 sites and nivalenol was detected in 10 sites. There was no significant correlation between the visual symptoms (AUDPC), the amount of Fusarium (quantitative PCR), and the amount of mycotoxins, implying that mycotoxin accumulation may have occurred in healthy-looking grain. Statistical analysis showed significant correlations between AUDPC and RH, temperature and LW. Only rainfall was significantly correlated with mycotoxin levels in 2001. Evidence of biomechanical and potential biochemical interactions at the seaweed bedrock interface Liam Morrison1, Martin Feely2, and Dagmar B. Stengel1 1Department of Botany, Martin Ryan Institute, National University of Ireland, Galway 2Department of Earth & Ocean Sciences, National University of Ireland, Galway In an interdisciplinary study, the mode of attachment of seaweeds to their bedrock substrate is under investigation. Preliminary observations indicate that seaweed rhizoids penetrate into granite and limestone bedrock in the Galway Bay area. This penetration causes physical disaggregation and fragmentation of the constituent minerals in the rock substrate. Furthermore, this physical interaction suggests there is also the potential for biochemical interaction between algal tissue and bedrock. This is in stark contrast to the current view that chemical species are taken up solely from seawater over the thallus surface. Thin-section studies of the granite-holdfast interface reveal evidence for the penetration of the algal tissue along, (a) cleavage planes of biotite and (b) intercrystalline boundaries of feldspar and quartz. Furthermore, the cleavage flakes of biotite are bent and separated by the seaweed holdfast; this is unequivocal evidence of biomechanical interaction. Quantification of Fungal Propagules in Bales of Grass Silage M. O’Brien1, 3, P. O’Kiely1, P.D. Forristal2 and H. Fuller3 1Teagasc, Grange Research Centre, Dunsany, Co. Meath; 2Teagasc, Crops Research Centre, Oak Park, Co. Carlow; 3Department of Botany, University College Dublin, Belfield, Dublin 4 Baled silage contains fungal propagules. Under favourable conditions some mould propagules germinate and contaminate silage, presenting potential health challenges to livestock and humans. The aim of this study was to develop a bale sampling method for the estimation of numbers of fungal propagules in baled silage. In late spring 2003, ten ‘big bales’ that were visibly mould-free were sampled with a steel corer in 8 positions on the bale barrel. Samples were individually suspended in Ringer’s solution and homogenised in a stomacher before being serially diluted. Mould and yeast counts were determined using the spread plate method on MYS agar. Statistical analyses were performed using SAS (ver. 6.12). Both mould and yeast cfu values (per g silage) varied greatly between bales and within bales. Yeast numbers were greater than those of mould and showed more variability between bales (s.e. 3.32) than within bales (s.e. 1.23). The variation in yeast numbers between and within bales was significant (P<0.05). The mould data set contained a large number of values close to zero and could not be analysed statistically. It was concluded that there was no one position in any of these bales that would be representative of the bale as a whole for either mould or yeast propagule numbers. In order to get a reasonable estimate of fungal propagule numbers in the outer horizon of a ‘big bale’, the authors recommend that sub-samples be taken at various points on a bale and then blended to provide one representative sample per bale. MicroRNA mining: Computational screening for non-coding epigenetic regulators of plant reproduction. Bryan O'Sullivan1, Sylvia Laouielle1, Marie Fahey1,2, Des Higgins1,2 and Charles Spillane1 1Dept of Biochemistry, University College Cork, Lee Maltings, Cork, Ireland 2Conway Institute, UCD, Belfield, Dublin Small RNAs such as microRNAs (miRNAs) and short interfering RNAs (siRNAs), are key components of an evolutionarily conserved system of RNA-based gene regulation in eukaryotes. MicroRNAs may play key roles in the regulation of gene expression during early organismal development. A range of miRNAs have now been shown to functionally interfere with expression of messenger RNAs encoding factors controlling important developmental and physiological processes in plants and animals, including heterochronic developmental timing, stem cell maintenance, apoptosis, cell proliferation and homeotic gene control. miRNAs act as negative regulators that can target mRNAs containing miRNA target sequences, resulting in either inhibition of protein synthesis or degradation of the mRNA targeted. We take an evolutionary bioinformatics approach to screen the entire sequenced genomes of selected model eukaryotes, including Arabidopsis & rice, in order to identify evolutionarily conserved microRNAs. Micropropagation of Salvia greggii variegata Phelan S.¹ Douglas G.C.¹ and Hunter A². ¹ Teagasc Kinsealy Research Centre, Malahide Rd, Dublin 17. ² Department of Crop Science, Horticulture and Forestry, UCD, Belfield, Dublin 4 Methods for the micropropagation of Salvia greggii variegata (Autumn Sage) are being developed to produce commercially viable plants, which retain their variegation. Shoots, from nursery stock plants, were collected and sterilised in 7% calcium hypochlorite for 15 minutes, followed by three five minute washes in sterile water. For shoot proliferation in vitro nodal explants were excised and cultured on MS medium containing BA (0.1mg/l) and IBA (0.01mg/l). Proliferated shoots were then rooted on ½ strength MS medium supplemented with IBA (0.01-10mg/l). The effects of Paclobutrazol (PAC) and Gibberellic acid (GA3) on shoot and internode length were also tested on 2 node explants cultured on MS containing PAC (0.1-2mg/l). The counter effect of PAC on GA3 was investigated on explants cultured in MS medium supplemented with PAC (1mg/l) and GA3 (1mg/l). Rooting was stimulated by IBA, with 1.0mg/l IBA achieving 100%. Survival of explants on weaning was 93-100%, with the maximum loss of variegation at 19%. Results from the PAC tests indicated that high concentrations of PAC reduced both the length of internodes and the number of nodes produced in vitro. GA3 had the opposite effect. After weaning, shoots treated with PAC and GA3 showed no visible differences to those, which were untreated. Genetic conflict, genomic imprinting & the intra-genomic reproductive battleground in higher plants. Aisling Doyle1, Guillaume Blanc2, Ken Wolfe2, Charles Spillane1 1Dept of Biochemistry, University College Cork, Lee Maltings 2.10, Cork, Ireland 2Dept of Genetics, Trinity College Dublin, Dublin, Ireland In both mammals and plants, genetic conflict due to the ‘selfish interests’ of the male and female genomes can occurs during reproduction over nutrient allocation from mother to offspring. Such genetic conflict between maternally-inherited versus paternally-inherited genes can result in parent-oforigin effects manifest as genomic imprinting or dosage effects. Genomic imprinting is an epigenetic parent-of-origin effect whereby imprinted genes exhibit differential expression, depending on whether the allele is of maternal or paternal origin. Thus, imprinted loci are functionally hemizygous. Genomic imprinting is only observed in mammals & flowering plants. While over 50 imprinted genes essential to embryonic development have been identified in mammals, little is known of the nature and role of imprinted genes in plants. Any essential role of imprinted genes in plants has until recently been inferred from inter-ploidy crosses, with only two imprinted genes identified to date (MEDEA & FWA) in Arabidopsis thaliana. The genetic conflict hypothesis of Moore & Haig (1991) specifically predicts that genomic imprinting has evolved because of such conflicting interests of maternal and paternal genes. To identify candidate genes undergoing genetic conflict during sexual reproduction in plants, we are conducting a bioinformatics screen based on molecular evolutionary theory as a prelude to functional characterisation of such genes in the Arabidopsis genome. Mannitol, protein and polyphenol concentrations as biomarkers of environmental stress in two high-shore species of Phaeophyta Mairead Walsh1, Charles Piggott1, Irene Ralston1, Maria Tuohy1, Dagmar B. Stengel2 Departments of Biochemistry1 and Botany2, National University of Ireland, Galway Potential biomarkers of environmental stress were assessed in the two brown marine macroalgae Pelvetia canaliculata and Fucus spiralis from 2 sites in Galway Bay, Spiddal and Oranmore. Highintertidal seaweeds are subjected to fluctuations in temperature, irradiance, nutrients regimes and osmotic stress during a tidal cycle. In addition to this regular exposure to extreme environmental change, P. canaliculata has an obligate endophytic Ascomycete Mycophyias ascophylli. While the physiological relationship between P. canaliculata and M. ascophylli remains unclear, M. ascophylli is known to utilise algal carbohydrates and is thought to turn ‘parasitic’ under prolonged submersion. While all plants of P. canaliculata are infected with this fungus, the degree of infection is controlled by local seawater salinity, and within plants, younger plant parts have a lower infection level. The combined effects on stress on seaweeds may lead to the upward or downward regulation of key biomarkers. Here, polyphenol and protein concentrations and mannitol to total carbohydrate concentrations were determined in different plants parts of P. canaliculata and F. spiralis from Spiddal (high salinity, high degree of fungal infection in P. canaliculata) and Oranmore (low salinity, little fungal infection). Significant differences in concentrations of all potential biomarkers were detected between the two species, between samples from the two sites sites and, within plants, between stipes, middle sections and tips. Detection and quantification of soil-borne inoculum of Spongospora subterranea f. sp. subterranea, the cause of powdery scab disease of potato J. M. Tuohy, X. Qu, D. Egan, J. A. Kavanagh & F. M. Doohan ERM Department, Faculty of Agriculture, University College Dublin Identification and quantification of resting spores (cystosori) of the biotrophic pathogen, Spongospora subterranea f. sp. subterranea in soil is an important step in the development of a strategic programme for the management of powdery scab disease of potato. The purpose of this study was to determine whether this quantitative PCR based method could be used to determine soil inoculum levels in field soils, irrespective of soil type. In the current study, uninfested (clean) soil samples were collected from three different regions in Ireland and were spiked with different concentrations of cystosori, ranging from 0.5-1x105 cystosori g-1 soil. Sub-samples of each soil were classified for texture. S. subterranea was successfully amplified from soil DNA extracts using species-specific polymerase chain reaction (PCR) primers resulting in a 434 bp product. Quantitative PCR was performed using a heterologous competitor template (541 bp) and standard curves were constructed for each soil type. No significant differences were found in resulting PCR product ratios of the three soils samples examined at any concentration of cystosori (P<0.001) and this method of quantification could detect as little as 5 cystosori g-1 soil. This quantification method therefore could be used to test inoculum levels in any soil sample, irrespective of soil type, and may be of significant interest for the possible routine screening of field soils, thereby aiding the development of a risk assessment model for this important potato disease. In vitro studies and analysis of Harpagophytum-the Devils Claw Levieille G., Cahill E., Caffrey E., Tennyson E. and Wilson G Department of Botany, University College Dublin Extracts of tubers of Devils Claw (Harpagophytum procumbens, Pedaliaceae) are widely used for the relief of muscular pain (Van Haelen et al. 1983), and biopharmaceutical activity has been shown in clinical studies (Chrubasic et al. 2002). The anti-inflammatory activity has been attributed to free and glycoside forms of iridoid monoterpenes harpagoside, harpagide, procumbine and harpagogenine. Previous studies (Levieille and Wilson, 2002) showed that Harpagophytum plants could be regenerated in vitro by nodal cuttings after a root induction treatment followed by transfer to a phytohormone free medium. The objective of this work is to compare the growth and iridoid content of in vitro plants grown by temporary immersion (TIS) with whole plants grown in a glasshouse in Ireland, and with commercially available Devils Claw extract. Impact of peat cutting on the genetic diversity of plant populations in Northern Ireland peat bogs Wilson PJ and Provan J School of Biology and Biochemistry, Queen’s University Belfast Habitat fragmentation is considered to be the single most serious threat to biological diversity worldwide. Peat bogs represent a unique ecosystem that is under particular threat from peat cutting and drainage and since many plant species are endemic to bog ecosystems, the effects of habitat are particularly detrimental in peatlands. The detrimental effects of fragmentation on population level genetic diversity are primarily due to the effects of genetic drift. Previous studies on plant populations in fragmented bog habitats have mostly reported a decrease in genetic variation in impacted populations. The aims of the study are to use molecular markers (nuclear and chloroplast microsatellites, inter-simple sequence repeats [ISSRs] and amplified fragment length polymorphisms [AFLP]) to determine the levels of genetic diversity present in a range of common plant species which are present in the peat bogs of Northern Ireland and to determine the levels of substructuring (if any) which are present between subpopulations of the species. Use of 1- methylcyclopropene on modified atmosphere packed apple fruit Nasrin Zangeneh and Micheal J. Hennerty Dept of Crop Science, Horticulture and Forestry, University College Dublin The effects of 1-methylcyclopropene (1-MCP; SmartFresh) on the response of Bramley’s Seedling) apples to modified atmosphere (MA) packaging was studied . Fruit samples were picked on 21 September 2003, the best commercial harvest date for this variety. Half of the apples were treated with (1- MCP) at a concentration of 626 ppb for 24 hours at 20ºC immediately after harvest. Apples treated with 1-MCP and untreated fruit were packed in MA films (five different materials and permeabilities) using a vacuum packaging machine and were held in a cold room at 5-7º C. Every two weeks, samples were examined for weight loss, colour, titratable acidity, flesh firmness, soluble solids, starch and tannins, all measures of postharvest quality. The atmosphere inside the MA packs was also measured every two weeks after packaging, and effects of MA packaging in combination with 1-MCP on fruit ripening changes were found to vary according to the bags typical values and permeabilities. Two films (MY and MRX manufactured by CRYOVAC Europe/ Sealed Air Limited London) proved satisfactory for long term MA storage of Bramley's Seedling. In general results indicated that 1- MCP improved fruit quality by 30 to 50%. Untreated MA packed fruit showed 20 to 35% more physiological disorders and fungal rots than treated MA packs. The effect of 1-MCP on soluble solids was unclear.
