Potential Honours projects
Stomatal protection mechanisms in Casuarinaceae
The family Casuarinaceae is a classic example of an Australian plant family that
has evolved in response to both low soil nutrients (scleromorphy) and low water
availability (xeromorphy). While this is very well understood, the full limits of
the xeromorphic response are not yet understood, but are vital in assisting us to
properly interpret the fossil record of this important family. The aim of this
project will be to collect foliage samples of several species of Casuarinaceae
across southern Australia to determine how much the morphology of the foliage
varies both within and between species in different climates. This will involve
some plant sectioning, plus some significant scanning electron microscopy. The
potential then exists to apply results found to fossil specimens of Casuarinaceae
to determine what this tells us about past climates. The data may also be used to
predict the likely fate of Casuarinaceae species in the face of future climate
change scenarios.
Evolution of photosynthetic organs in Acacia
Acacia has a very large number of species in Australia, many of them in relatively
arid environments. Most species have evolved a new photosynthetic organ, the
phyllode (the flattened and expanded leaf petiole) to assist surviving in these
environments. Phyllodes have a remarkable capacity to develop extra barriers
to water loss throughout their life cycle, but this has never been properly
documented. This project will involve assessing both field collected and
glasshouse grown specimens to document the morphology of the leaves and
phyllodes against the climate in which they grow. This can then be tested against
the limited fossil record of this genus.
Change in stomatal morphology through time at the Koonamore Reserve.
The Koonamore Reserve offers a unique field location worldwide, with
continuous records of arid zone recovery over a very long period of time. An
assessment of the stomatal morphology of many species can be made at the
present time, and the history of any changes can be documented via access to
herbarium specimens of the same species. Even during the course of the 20th
Century, this documents a remarkably rapid rise in atmospheric CO2, the impact
of which is poorly understood in arid areas.
Tropical Rainforest in Antarctic latitudes – the Golden Grove flora
45 million years ago, Australia was still connected to Antarctica and “tropical”
forests flourished along our south coast. There is still much to learn about how
such forests can thrive at very high latitudes, even in a warm and wet climate.
Golden Grove is a poorly researched but highly diverse fossil flora in South
Australia which has very well preserved leaf cuticles, allowing both stomatal
details and the presence of epiphyllous fungus to be well documented. Some
whole macrofossils are also available, but this will mostly be a study of dispersed
cuticle, in an attempt to:
1. Determine the overall species diversity
2. Some indication of the major plant families present
3. Whether stomatal morphology gives an indication of the prevailing
climate
4. Whether epiphyllous fungi can be used to provide relevant data on past
rainfall regimes.