Saltcedar (Tamarix)
Physiology - a Primer
Dr. Curtis E. Swift
Colorado State University
Cooperative Extension
Tamarix – uses in ancient times
• Charcoal from Tamarix twigs – found in
caves of Natufian culture (C. 12300-10500
BC) – Mount Carmel, Israel
Ley-Yadun, S., and Weinstein-Evron, M. 1994. Late
Epipalaeolitic wood remains from el-Wad Cave,
Mount Carmel, Israel, New Phytol. 127:391-396.
Tamarix – uses in ancient times
• Manna from Heaven - Manna
scale (Trabutina mannipara)
– Biblical manna - one of the food
sources consumed by the
Israelites during their
wanderings in the wilderness of
Sinai
Ben-dov, Y. 1988. Manna scale, Trabutina mannipara
(Hemprich & Ehrenberg) (Homoptera: Coccoidea:
Pseudococcidae) Systematic Entomology 13:387-392.
Manna scale
Trabutina mannipara
Saltcedar – in the United States
• Introduced by nurseryman in early
1800’s as an ornamental
• Later used as an erosion-control plant in
New Mexico
• 1920 - 40 or 50 thousand acres
• over one million acres by 1965
Anderson, J.E., 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63(1):48-56.
Saltcedar – in the United States
• Since the early 1900’s Tamarix has
rapidly invaded the ecosystem of the
lower Colorado River and its tributaries
– Resulted in the replacement of up to 90% of
the riparian communities historically
dominated by cottonwood-willow forests
Sala, A, and Smith, S.D. 1996. Water use by Tamarix
ramosissima and associated phreatophytes in a Mojave desert
floodplain. Ecological Applications 6(3):888-898.
Saltcedar Genus Tamarix
• Native to the Mediterranean region,
central Asian and north African deserts
• A naturalized shrub or small tree in U.S.
• Widely distributed phreatophyte in the
southwestern United States
Ginzburg, C. 1967. Organization of the adventitious root
apex in Tamarix aphylla. Amer. J. Bot. 54(1):4-8.
Floodplain survival
• Variety of environmental attributes
affect the mechanisms controlling
populational and ecological relationships
between floodplain species.
Cleverly, J.R., Smith, S.D., Sala, A., and Devitt, D.A. 1997.
Invasive capacity of Tamarix ramosissima in a Mojave Desert
floodplain: the role of drought. Oecologia 111:12-18.
Floodplain survival
of native species
• Willow is more tolerant of water and salt
stress than cottonwood
• Responsible for the persistence of Salix
vs. Populus on the Colorado River
Busch, D.E., and Smith, S.D. 1995. Mechanisms associated
with decline of woody species in riparian ecosystems of the
Southwestern U.S. Ecological Monographs 65(3):347-370.
Tamarix success as
an invasive plant
• Success in the floodplain results
from:
– ability to grow rapidly in wet years
– ability to tolerate or avoid extreme
water and heat stress in drought years
Cleverly, J.R., Smith, S.D., Sala, A., and Devitt, D.A. 1997.
Invasive capacity of Tamarix ramosissima in a Mojave Desert
floodplain: the role of drought. Oecologia 111:12-18.
Tamarix success as
an invasive plant
• tolerant of desiccation of
watercourses
Blackburn, W.H., Knight, R.W., and Schuster, J.L. 1982.
Saltceder influence on sedimentation in the Brazos River. J. Soil.
Water. Conserv. 37:298-301
Tamarix success as
an invasive plant
• tolerant of salinization of surface
soils
Busch, D.E., and Smith, S.D. 1993. Effects of fire on water and
salinity relations of riparian woody taxa. Oecologia 94:186-194.
Tolerance of Floods
• Salt grass and dwarf willow developing
on sand bars – shallow roots - swept away
by floods
• Tamarisk is hardy enough to withstand
floods, continue to grow, stabilize the
underlying surface, and trap sediments
Graf, W.L. 1978. Fluvial adjustments to the spread of
tamarisk in the Colorado Plateau region. Bulletin
Geological Society of America 89(10):1491-1501.
Plant Success
• When a species is competitively superior
under both wet years and drought, it
would be expected to persist as the sole
species through successional time.
Cleverly, J.R., Smith, S.D., Sala, A., and Devitt, D.A. 1997.
Invasive capacity of Tamarix ramosissima in a Mojave
Desert floodplain: the role of drought. Oecologia 111:12-18.
Tamarix invasiveness
• Plant spread upstream at ~ 20 km/yr (12
mile/yr).
– Colorado and Green River in Utah
Graf, W.L. 1978. Fluvial adjustments to the spread of
tamarisk in the Colorado Plateau region. Bulletin Geological
Society of America 89(10):1491-1501.
Tamarix invasiveness
• Annual production of 600,000 windborne seeds
for each mature tamarisk tree
Robinson, T.W. 1958. Phreatophytes. US Geological
Survey Water-supply paper 1423:70-75.
• Spreads rapidly by layering
Wilkinson, R.E. 1966. Adventitious roots on saltcedar
roots. Bot. Gaz. 127(2-3):103-104.
Tamarix invasiveness
• All the aboveground portions of saltcedar will
develop adventitious roots and form new
shrubs if kept wet in moist soil.
• ~100% of stem cuttings sprout at all times of
the year if kept moist and warm.
Horton, J.S. 1977. The development and perpetuation of the
permanent Tamarisk Type in the phreatophyte zone of the
southwest. USDA, FS, General technical report RM 43:124127.
Tamarix invasiveness
Fluvial Adjustments
•
•
•
•
Islands have become longer and wider
Channel-side bars have widened
Some alluvial-fan surfaces have expanded
Resulted in:
– Reduction in channel widths
– Flooding over the bank
Graf, W.L. 1978. Fluvial adjustments to the spread of
tamarisk in the Colorado Plateau region. Bulletin
Geological Society of America 89(10):1491-1501.
Phreatophytes
• Plants that are tightly linked to aquifers
for water uptake.
– Dependent on groundwater (water table and
capillary fringe) as a moisture source.
Busch, D.E., Ingraham, N.L., and Smith, S.D. 1992. Water
uptake in woody riparian phreatophytes of the southwestern
United States: a stable isotope study. Ecological applications
2(4):450-459.
Phreatophytes
Phreat = well; phyte = plant
Can absorb water deep and release it
at or near the soil surface.
The soil surface is where nutrients are
most available.
Waisel, Y, Eshel, A., and Kafkafi, U. 1996. Plant Roots: the
hidden half. Marcel Dekker, Inc. New York, NY
Phreatophytes
• Classified on type of water required
– Groundwater – water table or
capillary fringe
– Moisture from unsaturated soils
Busch, D.E., Ingraham, N.L., and Smith, S.D. 1992. Water
uptake in woody riparian phreatophytes of the southwestern
United States: a stable isotope study. Ecological applications
2(4):450-459.
Phreatophyte - Definitions
• Obligate - require uninterrupted
access to saturated soil
– Roots in water table or capillary fringe
• Cottonwood and willow
Turner, R.M. 1974. Quantitative and historical evidence of
vegetation changes along the upper Gila River, Arizona. USGS
Professional Paper 655-(H):1-20.
Phreatophyte - Definitions
• Facultative
able to use water from the water table
and associated capillary fringe
– able to extract water and survive
indefinitely in unsaturated soils.
–
• Tamarix
Everitt, B.L. 1980. Ecology of saltcedar – a plea for research.
Environ. Geol. 3:77-84
Facultative Phreatophytes
• Ability to use water from unsaturated soil
have a greater ability to:
– withstand stress tolerance
– increase their nutrient uptake
• soil nutrients are often more abundant above the
saturated zone
Pinay, G., Fabre, A., Vervier, P., and Gazelle, F. 1992.
Control of C, N, P, distribution in soils of riparian forests.
Landscape Ecol 6:121-132.
The Vascular System
Water Uptake of
Saltcedar
Straight ascent
turning into ring
ascent
• Waisel, Y., Liphschitz, N., and
Kuller, Z. 1972. Patterns of
water movement in trees and
shrubs. Ecology 53(3):520-523.
Phreatophytes
• Have roots that extend down to the water
table or other periodically stable water
supply
• Roots can extend to a depth of 53 meters
Waisel, Y, Eshel, A., and Kafkafi, U. 1996. Plant Roots: the
hidden half. Marcel Dekker, Inc. New York, NY
Tamarix
• The genus is generally characterized by a
deep and intensively branched root
system.
• Adventitious roots develop from the
lenticels.
Ginzburg, C. 1967. Organization of the adventitious root
apex in Tamarix aphylla. Amer. J. Bot 54(1):4-8.
Root Development
• Salix
– root elongation rates are slow
– emphasis on lateral root growth
• helps protect against late season flood scour
• Tamarix
– Greater root elongation rate
– Allows seedlings to persist in dry soils while
Salix seedlings die
Horton, J.L., and Clark, J.L. 2001. Water table decline alters growth and
survival of Salix gooddingii and Tamarix chinensis seedlings. Forest
Ecology and Management 140:239-247.
Root Development
• Populus seedlings – 0.6 – 1.3 cm/day
– 72-162 cm by end of first season
• Salix seedlings – 1.0 – 2.1 cm/day
Horton, J.L., and Clark, J.L. 2001. Water table decline
alters growth and survival of Salix gooddingii and Tamarix
chinensis seedlings. Forest Ecology and Management
140:239-247.
Saltcedar
• Reputation as the heaviest water user of
all the phreatophytes
Gay, L.W., Sammis, T.W., and Ben-Asher, J. 1976. An energy
budget analysis of evapotranspiration from saltcedar.
Hydrology and water resources in Arizona and the southwest
7:133-139.
Water Use by Saltcedar
• Able to desiccate floodplains and lower
water tables
Blackburn, W.H., Knight, R.W., and Schuster, J.L. 1982.
Saltcedar influence on sedimentation in the Brazos River.
J. Soil. Water. Conserv. 37: 298-301
Saltcedar
• T. chinensis with adequate water
transpires copiously
• Rates are similar to other phreatophytes
in same area
Anderson, J.E., 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63(1):48-56.
Transpiration
• Exchange of water vapor between the
plant canopy and the atmosphere
• depends upon air and leaf temperatures
– atmospheric humidity
– aerodynamic or boundary layer resistance
– leaf diffusive (stomata) resistance
Anderson, J.E., 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63(1):48-56.
Transpiration of Saltcedar
• Stomata respond to temperature,
humidity, and light intensity
* Gas exchange
* Vapor release
Transpiration of Saltcedar
• 20o C (68o F) and 45% RH
– saltcedar twigs transpire a weight of water
greater than their own fresh leaf weight each
hour.
– Similar rate to common herbaceous plants
– Not unusually high where compared with
other plants with an abundant water supply.
Anderson, J.E. 1977. Transpiration and Photosynthesis in
saltcedar. Hydrology and water resources in Arizona and the
Southwest 7:125-131.
Transpiration Rates
• At 30 C (85 F) and 45% RH
– Populus fremontii and Eleagnus angustifolia
practically identical to saltcedar Tamarix
chinensis.
Anderson, J.E., 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63(1):48-56.
Transpiration
• Tamarix is more drought tolerant than
Salix
• Salix transpires more water per unit leaf
surface area and is less tolerant of
seasonal water stress than Tamarix
Cleverly, J.R., Smith, S.D., Sala, A., and Devitt, D.A. 1997.
Invasive capacity of Tamarix ramosissima in a Mojave Desert
floodplain: the role of drought. Oecologia 111:12-18.
Saltcedar & Flooding
• Inundation for 36 months results in 99%
plant kill whether the trees were partially or
entirely submerged.
• Inundated trees did not foliate the third
growing season – 24 months of inundation
may be adequate
Wiedemann, H.T., and Cross, B.T. 1978.Water inundation for
control of saltcedar along the periphery of lakes. Proceedings,
Southern Weed Science Society 31:229.
Photosynthesis in Saltcedar
• Photosynthetic tissue
– Cladophylls
• Cylindrical leaf-like photosynthetic stems
• Bear two sizes of whorled clasping leaves
– scale-like – 3 mm in length
– Cauline leaves – 8 – 9 mm long
– Covered with a white salt “bloom”
Wilkinson, R.E. 1966. Seasonal development of anatomical
structures of saltcedar foliage. Bot. Gaz. 127(4):231-234.
Saltcedar leaf surface has
a waxy covering
• Composition and quantity varies seasonal
differences in temperature and rainfall
• Quantity and composition of waxes on leaves
of salt cedar is thought to be the basis for
differences in sensitivity to herbicides
Mayeux, J.S., Jr., Jordan, W.R. 1984. Variation in amounts
of epicuticular wax on leaves of Prosopis gladulosa. Bot. Gaz.
145(1):26-32.
Tamarix Cuticle development
Wilkinson, R.E. 1966. Seasonal development of anatomical
structures of saltcedar foliage. Bot. Gaz. 127(4):231-234
Tamarix Cuticle development
Wilkinson, R.E. 1966. Seasonal development of anatomical
structures of saltcedar foliage. Bot. Gaz. 127(4):231-234
Tamarix Cuticle development
In addition, the
quantity and
composition of wax
on leaf surfaces of
tamarisk varies
during the season
Wilkinson, R.E. 1966. Seasonal development of anatomical
structures of saltcedar foliage. Bot. Gaz. 127(4):231-234
Tamarix Cuticle development
Wilkinson, R.E. 1966. Seasonal development of anatomical
structures of saltcedar foliage. Bot. Gaz. 127(4):231-234
Photosynthesis
• optimum leaf temperatures for
photosynthesis between 23 and 28 C
(73 – 82 F)
• at 35 C (95 F) photosynthesis reduced
about 20%
Anderson, J.E. 1977. Transpiration and Photosynthesis in
saltcedar. Hydrology and water resources in Arizona and the
Southwest 7:125-131.
Photosynthesis
 net photosythetic
rate
• transpiration
rate
Anderson, J.E. 1977. Transpiration and Photosynthesis in
saltcedar. Hydrology and water resources in Arizona and the
Southwest 7:125-131.
Photosynthesis
Optimum temperature 23 - 28 C (73 – 82 F)
• Photosynthesis is optimum in early part
of day
• Time with lower evaporation and
transpiration demands
Anderson, J.E., 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63(1):48-56.
Photosynthesis
Observed optimum temperature
23 - 28 C (73 – 82 F)
• To maximize photosynthesis during hottest
part of the day would result in much higher
transpiration losses relative to carbon gains
Anderson, J.E., 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63(1):48-56.
Stomata
• Close in response to increasing
temperature
• Saltcedar
– insures seedling survival until the root
system taps water table
– enables plant to invade and succeed in areas
subjected to periodic drought.
Anderson, J.E. 1977. Transpiration and Photosynthesis in
saltcedar. Hydrology and water resources in Arizona and the
Southwest 7:125-131.
Photosynthesis & Saltcedar
• Light saturated at 44% of full sunlight
– 1100 nEinstein m-2 s-1 at 400 to700 nm
• Rate of photosynthesis is considerably
lower than the rates for herbaceous
plants.
Anderson, J.E. 1977. Transpiration and Photosynthesis in saltcedar.
Hydrology and water resources in Arizona and the Southwest 7:125-131.
Photosynthesis
• Light cloud cover reduces irradiation
below saturation, reducing photosynthesis
• Stomata close to conserve moisture when
light is limiting to photosynthesis
Anderson, J.E., 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63(1):48-56.
Stomata close to
conserve moisture when light
is limiting
– Similar conclusion in other studies
• Populus spp.
Pallardy, S.G., and Kozlowski, T.T. 1979. Stomata response of Populus clones
to light intensity and vapor pressure deficit. Plant Physi90logy 64:112-114..
• Picea engelmanii
Kaufman, M.R. 1976. Stomatal response of Engelmann spruce to humidity,
light, and water stress. Plant Science Letters 3:898-901.
Stomata and light intensity
• With most plants
– Drop in light intensity
• Stomata close slowly
– Increase in light intensity
• Stomata open rapidly
Woods, D.B., and Turner, N.C. 1971. Stomatal response to
changing light by four tree species of varying shade tolerance.
New Phytologist 70:77-84.
Stomata and light intensity
• Saltcedar
– Drop in light intensity
• Stomata close rapidly
– Increase in light intensity
• Stomata open slowly
• A mechanism to reduce water loss
Anderson, J.E., 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63(1):48-56.
Water use efficiency
Photosynthesis vs. water uptake
• Tamarix has the highest water use
efficiency of the woody riparian taxa
investigated – Populus, Salix
– Based on carbon isotope research
Busch, D.E., and Smith, S.D. 1995. Mechanisms associated
with decline of woody species in riparian ecosystems of the
southwestern U.S. Ecological Monographs. 65(3):347-370.
Water use efficiency
Photosynthesis vs. transpiration
• Tamarix chinensis
– 4.3 mg water/g dry weight of tissue (dwt)
• Populus fremontii
– 6.8 mg/g dwt
• Eleagnus angustifolia
– 6.7 mg/g dwt
Anderson, J.E. 1982. Factors controlling transpiration and
photosynthesis in Tamarix chinensis Lour. Ecology 63:48-56.
Water use efficiency
Photosynthesis vs. transpiration
• Salix and Tamarix - comparable rates Mojave desert
Cleverly, J.R., Smith, S.D., Sala, A., and Devitt, D.A. 1997.
Invasive capacity of Tamarix ramosissima in a Mojave Desert
floodplain: the role of drought. Oecologia 111:12-18.
Salt effect on Photosynthesis
and Transpiration
• Rates of photosynthetic carbon fixation and
transpirational water loss changed very little
with increasing salt treatment
• Reduction in growth with increased salt levels
were due to increased respiration and/or salt
pumping
Kleinkopf, G.E., and Wallace, A. 1974. Physiological basis for
salt tolerance in Tamarix ramosissima. Plant Sci. Ltr. 3:157163.
Salts and plant growth
• Excess soluble salts in the soil
– Decrease absorption of essential
nutrients
– May have a direct toxic effect
– May increase osmotic gradient and
prevent adequate water uptake
Hayward, H.E., and Berstein, L. 1958. Plant-growth
relationships on salt-affected soils. Bot. Rev. 24:584-635.
Salts and plant growth
• Osmotic effects of soluble salts are
the most detrimental single factor to
vegetation in saline areas.
Hayward, H.E., and Wadleigh, C.H. 1949. Plant-growth
relationships on salt-affected soils. Advances in Agron. 1:1-38.
Salt uptake
• Trees capable of accumulating salts
can maintain turgor and high leaf
conductance as tissue water potential
declines; other plants are required to
close their stomates to maintain
turgor.
Osonubi, O., and Davies, W.J. 1978. Solute accumulation in
leaves and roots of woody plants subjected to water stress.
Oecologia 32:3223-332.
Tamarix survival on saline soils
• maintain high uptake of ions
a. salt extrusion by salt glands
b. cellular compartmentation
c. utilization for osmoregulation
Greenway, H., and Munns, R. 1980. Mechanisms of salt
tolearance in nonhalophytes. Annual Review of Plant
Physiology. 31:149-190.
Salt glands and epidermal salt
hairs
• Function in ion regulation
• salt hairs accumulate ions and
excrete them from leaves, regulating
cellular ionic content
Karimi, S.H., and Ungar, I.A. 1989. Development of epidermal
salt hairs in Atriplex triangularis willd. in response to salinity,
light intensity, and aeration. Bot. Gaz. 150(1):68-71.
Salt Hairs & Glands of
Halophytes
• Form in early stages of development
• Critical for the salt tolerance of
young developing halophytes
Karimi, S.H., and Ungar, I.A. 1989. Development of epidermal
salt hairs in Atriplex triangularis willd. in response to salinity,
light intensity, and aeration. Bot. Gaz. 150(1):68-71.
Salt hairs – secondary
functions
• Reduction of intense illumination
• Insulation against excessive heat to
reduce transpiration
• Water storage
• Water absorption
Ehleringer, J., and Bjorkman, C.J. 1978. Leaf hairs: effects on
physiological activity and adaptive value to a desert shrub.
Oecologia 37:183-200.
Tamarix Salt Gland
Cuticle
Pore
Secretory Cells
Collecting Cell
Fahn, A. 1988. Tansley Review No. 14. Secretory tissues
in vascular plants. New Phytol 108:229-257.
Tamarix Salt Gland
• Salts (chlorides) move through the
apoplast from the xylem to the salt glands
• Cuticle almost completely separates salt
glands from the mesophyll tissue
• A subcuticular space (collecting
chamber/cell) between the cuticle and the
gland
Campbell, N., and Thomson, W.W. 1975. Chloride
localization in the leaf of Tamarix. Protoplasma 83:1-14.
Tamarix Salt Gland
Numerous mitochrondria
Nuclei
Requires energy
Fahn, A. 1988. Tansley Review No. 14. Secretory tissues
in vascular plants. New Phytol 108:229-257.
Tamarix Salt Glands
• Young and mature stems and leaves
possess numerous salt glands
Bosabilidis, A.M., and Thomson, W.W. 1984. Ultrastructural
differentiation of an unusual structure lining the anticlinal
walls of the inner secretory cells in Tamarix salt glands. Bot.
Gaz. 145(4):427-435.
Salt Glands
• Assumed salt glands secrete sodium
chloride in large quantities
• Sodium chloride secretion has been used
synonymously with salt secretion
Arisz, W.H. Camphuis, J., Heikens, H. and van Tooren, A.J.
1955. The secretion of the salt glands of Imonium latifolium.
Acta Bot. Nerr. 4:322-338.
Sodium in Halophytes
• The level of sodium in halophytes is
low
– cytoplasm is largely by-passed by
sodium perhaps by transport in small
vesicles
Hall, J.L. and Flowers, T.J.1973. The effect of of salt on protein
synthesis in the haloophyte Suaeda maritina. Planta. 110:361.
Sodium transport in Tamarix
• Most of Na transported to leaves is
excreted by salt glands
• Na accumulates in large quantities when
present in high concentration in the
nutrient solution
• Na concentration in roots and stems is
much lower than in leaves
Kleinkopf, G.E., and Wallace, A. 1974. Physiological basis for
salt tolerance in Tamarisd ramosissima. Plant Sci. Ltr. 3:157163.
Tamarix survival on saline soils
• Ions detected in high concentration in
leaf tissue are also found at high
concentrations in soil and water
• Secreted ions represent ions in the soil
and solution
Berry, W.L. 1970. Characteristics of salt secreted by Tamarix
aphylla. American Journal of Botany 57:1226-1230.
Salt Secretion
• Bicarbonates are excreted in large
amounts (60%) even when not in the soil
solution
– metabolically produced; requires energy
• Tamarix secretes actively even under low
salt conditions
Berry, W.L. 1970. Characteristics of salt secreted by Tamarix
aphylla. American Journal of Botany 57:1226-1230.
Physiology
• a branch of biology that deals with the
functions and activities of life or of living
matter (as organs, tissues, or cells) and of the
physical and chemical phenomena involved
• the organic processes and phenomena of an
organism or any of its parts or of a particular
bodily process
Merriam-Webster Collegiate Dictionary:
http://m-w.com/cgi-bin/dictionary
Tamarix Physiology
• An effective invader of riparian
areas
• Successful competitor with
native species
• Thank you!