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

Journal Article · Tue Jan 01 00:00:00 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), Vol. 4
• Country of Publication: United States
• Language: English

Related Subjects

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