Carbon dioxide and light responses of photosynthesis in cowpea and pigeonpea during water deficit and recovery

Journal Article · Thu Oct 01 04:00:00 EDT 1987 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.85.4.990· OSTI ID:5513949

Lopez, F B; Setter, T L; McDavid, C R

Greenhouse-grown pigeonpea (Cajunus cajan, (L.)) and cowpea (Vigna unguiculata, (L.)) were well-watered or subjected to low water potential by withholding water to compare their modes of adaptation to water-limited conditions. Leaf CO/sub 2/ exchange rate (CER), leaf diffusive conductance to CO/sub 2/ (g/sub L/), and CO/sub 2/ concentration in the leaf intercellular air space (C/sub i/) were determined at various CO/sub 2/ concentrations and photon flux densities (PFD) of photosynthetically active radiation. In cowpea, g/sub L/ declined to less than 15% of controls and total water potential (Psi/sub w/) at midafternoon declined to -0.8 megapascal after 5 days of withholding water, whereas g/sub L/ in pigeonpea was about 40% of controls even though midafternoon Psi/sub w/ was -1.9 megapascal. After 8 days of withholding water, Psi/sub w/ at midafternoon decline to -0.9 and -2.4 megapascals in cowpea and pigeonpea, respectively. The solute component of water potential (Psi/sub s/) decreased substantially less in cowpea than pigeonpea. Photosynthetic CER at saturation photon flux density (PFD) and ambient external CO/sub 2/ concentration on day 5 of withholding decreased by 83 and 55% in cowpea and pigeonpea, respectively. When measured at external, CO/sub 2/ concentration in bulk air of 360 microliters per liter, the CER of cowpea had fully recovered to control levels 3 days after rewatering; however, at 970 microliters per liter the PFD-saturated CERS of both species were substantially lower than in controls, indicating residual impairment.

• Research Organization: Univ. of the West Indies, Trinidad
• OSTI ID: 5513949
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 85:2; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550500* -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
BACTERIA
BIOLOGICAL ADAPTATION
BIOLOGICAL RECOVERY
BIOLOGICAL STRESS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CELL CONSTITUENTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHLOROPLASTS
ELECTROMAGNETIC RADIATION
FOOD
HYDROGEN COMPOUNDS
LEGUMINOSAE
MICROORGANISMS
OXIDES
OXYGEN COMPOUNDS
PEAS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
RADIATIONS
RECOVERY
RHIZOBIUM
SYNTHESIS
VEGETABLES
VISIBLE RADIATION
WATER