Mild water stress of Phaseolus vulgaris plants leads to reduced starch synthesis and extractable sucrose phosphate synthase activity

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.89.4.1066· OSTI ID:6644189

Vassey, T L; Sharkey, T D ^[1]

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1. Univ. of Wisconsin, Madison (USA)

Mild water stress, on the order of {minus}1.0 megapascals xylem water potential, can reduce the rate of photosynthesis and eliminate the inhibition of photosynthesis caused by O{sub 2} in water-stress-sensitive plants such as Phaseolus vulgaris. To investigate the lack of O{sub 2} inhibition of photosynthesis, we measured stromal and cytosolic fructose-1,6-bisphosphatase, sucrose phosphate synthase, and partitioning of newly fixed carbon between starch and sucrose before, during, and after mild water stress. The extractable activity of the fructose bisphosphatases was unaffected by mild water stress. The extractable activity of SPS was inhibited by more than 60% in plants stressed to water potentials of {minus}0.9 megapascals. Water stress caused a decline in the starch/sucrose partitioning ratio indicating that starch synthesis was inhibited more than sucrose synthesis. We conclude that the reduced rate of photosynthesis during water stress is caused by stomatal closure, and that the restriction of CO{sub 2} supply caused by stomatal closure leads to a reduction in the capacity for both starch and sucrose synthesis. This causes the reduced O{sub 2} inhibition and abrupt CO{sub 2} saturation of photosynthesis.

• OSTI ID: 6644189
• Journal Information: Plant Physiology; (USA), Journal Name: Plant Physiology; (USA) Vol. 89:4; ISSN 0032-0889; ISSN PLPHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
BIOLOGICAL STRESS
BIOSYNTHESIS
CARBOHYDRATES
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
DISACCHARIDES
ELEMENTS
ENZYME ACTIVITY
ENZYMES
HYDROGEN COMPOUNDS
INHIBITION
LEGUMINOSAE
LIGASES
MAGNOLIOPHYTA
MAGNOLIOPSIDA
NONMETALS
OLIGOSACCHARIDES
OPENINGS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
PHASEOLUS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
POLYSACCHARIDES
REAGENTS
SACCHARIDES
SACCHAROSE
STARCH
STOMATA
SYNTHESIS
WATER