Transpiration and CO/sub 2/ fixation of selected desert shrubs as related to soil-water potential

Journal Article · Tue Jan 01 04:00:00 EST 1980 · Great Basin Nat.; (United States)

OSTI ID:6645424

Clark, S B; Letey, J Jr; Lunt, O R; Wallace, A; Kleinkopf, G E; Romney, E M

In desert plants, transpiration rates decreased before photosynthetic rates when plants were entering a period of water stress. This may have adaptive consequences. A difference of -5 bars in the soil-moisture potential had considerable importance in reducing the rate of transpiration. In Helianthus annuus L. (sunflower) the photosynthetic rate decreased before the transpiration rate in contrast to Great Basin-Mojave Desert plants, and the changes occurred with a -1 bar difference in soil-moisture potential. Morphological changes in three desert plant species (Artemisia tridentata Nutt., Ambrosia dumosa (Gray) Payne, Larrea tridentata (Ses. Moc. ex DC) Cov.) as the soil-moisture potential decreased are given. With a mesic species, H. annuus, 20% reduction in photosynthesis and transpiration was reached at higher soil-moisture potentials than with the desert plants. Loss of net photosynthesis occurred in A. dumosa (a summer deciduous shrub) as PSI soil reached -48 bars in the field, whereas L. tridentata (an evergreen shrub) at the same time was able to maintain a water potential difference between soil and plant of -10 to -15 bars and continue net CO/sub 2/ gain well into the summer months.

• OSTI ID: 6645424
• Journal Information: Great Basin Nat.; (United States), Journal Name: Great Basin Nat.; (United States) Vol. 4; ISSN GRBNA
• Country of Publication: United States
• Language: English

Related Subjects

510100* -- Environment
Terrestrial-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
550500 -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
ARID LANDS
CHEMICAL REACTIONS
DATA
DESERTS
EXPERIMENTAL DATA
INFORMATION
MOISTURE
NUMERICAL DATA
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
SHRUBS
SOILS
SYNTHESIS
TRANSPIRATION