Acclimation of photosynthesis to low leaf water potentials

Journal Article · Sun Jan 01 04:00:00 EST 1984 · Plant Physiol.; (United States)

DOI:https://doi.org/10.1104/pp.74.1.161· OSTI ID:5941802

Matthews, M A; Boyer, J S

Photosynthesis is reduced at low leaf water potentials (PSI/sub l/) but repeated water deficits can decrease this reduction, resulting in photosynthetic acclimation. The contribution of the stomata and the chloroplasts to this acclimation is unknown. The authors evaluated stomatal and chloroplast contributions when soil-grown sunflower (Helianthus annuus L.) plants were subjected to water deficit pretreatments for 2 weeks. The relationship between photosynthesis and PSI/sub l/, determined from gas-exchange and isopiestic thermocouple psychometry, was shifted 3 to 4 bars towards lower PSI/sub l/ in pretreated plants. Leaf diffusive resistance was similarly affected. Chloroplast activity, demonstrated in situ with measurements of quantum yield and the capacity to fix CO/sub 2/ at all partial pressures of CO/sub 2/, and in vitro by photosystem II activity of isolated organelles, was inhibited at low PSI/sub l/ but less in pretreated plants than in control plants. The magnitude of this inhibition indicated that decreases in chloroplast activity contributed more than closure of stomata both to losses in photosynthesis and to the acclimation of photosynthesis to low PSI/sub l/. 32 references, 8 figures.

• Research Organization: Univ. of Illinois, Urbana
• OSTI ID: 5941802
• Journal Information: Plant Physiol.; (United States), Journal Name: Plant Physiol.; (United States) Vol. 74; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505 -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
550500* -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CELL CONSTITUENTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHLOROPLASTS
DIFFUSION
HYDROGEN COMPOUNDS
LEAVES
OPENINGS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC REACTION CENTERS
PLANTS
SENSITIVITY
STOMATA
SUNFLOWERS
SYNTHESIS
WATER