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

Abstract

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.

Authors:
;  [1]
  1. (Univ. of Wisconsin, Madison (USA))
Publication Date:
OSTI Identifier:
6644189
Alternate Identifier(s):
OSTI ID: 6644189
Resource Type:
Journal Article
Resource Relation:
Journal Name: Plant Physiology; (USA); Journal Volume: 89:4
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; LIGASES; ENZYME ACTIVITY; PHASEOLUS; PHOTOSYNTHESIS; SACCHAROSE; BIOSYNTHESIS; STARCH; BIOLOGICAL STRESS; CARBON DIOXIDE; INHIBITION; OXYGEN; STOMATA; WATER; CARBOHYDRATES; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; CHEMICAL REACTIONS; DISACCHARIDES; ELEMENTS; ENZYMES; HYDROGEN COMPOUNDS; LEGUMINOSAE; MAGNOLIOPHYTA; MAGNOLIOPSIDA; NONMETALS; OLIGOSACCHARIDES; OPENINGS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PHOTOCHEMICAL REACTIONS; PLANTS; POLYSACCHARIDES; REAGENTS; SACCHARIDES; SYNTHESIS 550200* -- Biochemistry

Citation Formats

Vassey, T.L., and Sharkey, T.D.. Mild water stress of Phaseolus vulgaris plants leads to reduced starch synthesis and extractable sucrose phosphate synthase activity. United States: N. p., 1989. Web. doi:10.1104/pp.89.4.1066.
Vassey, T.L., & Sharkey, T.D.. Mild water stress of Phaseolus vulgaris plants leads to reduced starch synthesis and extractable sucrose phosphate synthase activity. United States. doi:10.1104/pp.89.4.1066.
Vassey, T.L., and Sharkey, T.D.. Sat . "Mild water stress of Phaseolus vulgaris plants leads to reduced starch synthesis and extractable sucrose phosphate synthase activity". United States. doi:10.1104/pp.89.4.1066.
@article{osti_6644189,
title = {Mild water stress of Phaseolus vulgaris plants leads to reduced starch synthesis and extractable sucrose phosphate synthase activity},
author = {Vassey, T.L. and Sharkey, T.D.},
abstractNote = {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.},
doi = {10.1104/pp.89.4.1066},
journal = {Plant Physiology; (USA)},
number = ,
volume = 89:4,
place = {United States},
year = {Sat Apr 01 00:00:00 EST 1989},
month = {Sat Apr 01 00:00:00 EST 1989}
}
  • Phaseolus vulgaris L. leaves were subjected to various light, CO/sub 2/, and O/sub 2/ levels and abscisic acid, then given a 10 minute pulse of /sup 14/CO/sub 2/ followed by a 5 minute chase with unlabeled CO/sub 2/. After the chase period, very little label remained in the ionic fractions except at low CO/sub 2/ partial pressure. Most label was found in the neutral, alcohol soluble fraction or in the insoluble fraction digestable by amyloglucosidase. Sucrose formation was linearly related to assimilation rate. Starch formation increased linearly with assimilation rate, but did not occur if the assimilation rate was belowmore » 4 micromoles per square meter per second. Neither abscisic acid, nor high CO/sub 2/ in combination with low O/sub 2/ caused significant perturbations of the sucrose/starch formation ratio. These studies indicate that the pathways for starch and sucrose synthesis both are controlled by the rate of net CO/sub 2/ assimilation, with sucrose the preferred product at very low assimilation rates.« less
  • Growth-chamber studies were conducted to examine the ability of seven vegetable crops- Blue Lake beam (Phaseolus vulgaris L.) Detroit Dark Red beet (Beta vulgaris L.) Burgundy okra (Abelmoschus esculentus) (Moench), Little Marvel pea (Pisum sativum L), California Wonder bell pepper (Capsicum annuum L), New Zealand spinach (Spinacia oleracea L), and Beefsteak tomato (Lycopersicon esculentum Mill.) - to adjust osmotically in response to water-deficit stress. Water stress was imposed by withholding water for 3 days, and the adjustment of leaf and root osmotic potentials upon relief of the stress and rehydration were monitored with thermocouple psychrometers. Despite similar reductions in leafmore » water potential and stomatal conductance among the species studied reductions in lead water potential an stomatal conductance among the species, crop-specific differences were observed in leak and root osmotic adjustment. Leaf osmotic adjustment was observed for bean, pepper, and tomato following water-deficit stress. Root osmotic adjustment was significant in bean, okra, pea and tomato. Furthermore, differences in leaf and root osmotic adjustment were also observed among five tomato cultivars. Leaf osmotic adjustment was not associated with the maintenance of leaf growth following water-deficit stress, since leaf expansion of water-stressed bean and pepper, two species capable of osmotic adjustment, was similar to that of spinach, which exhibited no leaf osmotic adjustment.« less
  • The incorporation of uniformly labeled leucine-/sup 14/C into protein by a chloroplast-containing fraction from developing primary leaves of bean is reported. Chloroplasts, obtained from week old plants grown in darkness, and then illuminated with white light for 12 hours, were shown to be the principal sites of incorporating activity. Incorporation may continue for 2 hours. Rates of up to 50 ..mu mu..mole leucine incorporated per mg protein per hour are observed when a 1 hour assay period is used. Incorporation is only partially sensitive to ribonuclease. 33 references, 3 figures, 3 tables.
  • Protein phosphorylation has been identified as a mechanism for the light-dark regulation of spinach sucrose-phosphate synthase (SPS) activity, previously shown to involve some type of covalent modification of the enzyme. The 120 kD subunit of SPS in extracts of light-treated leaves was labeled with {sup 32}P in the presence of ({gamma}-{sup 32}P) ATP. In this in vitro system, {sup 32}P incorporation into light-activated SPS was dependent upon ATP and magnesium concentrations as well as time, and was closely paralleled by inactivation of the enzyme. The soluble protein kinase involved in the interconversion of SPS between activated and deactivated forms maymore » be specific for SPS as it co-purifies with SPS during partial purification of the enzyme. The kinase appears not to be calcium activated and no evidence has been obtained for metabolite control of SPS phosphorylation/inactivation.« less
  • The effect of carbon monoxide and light on the respiration of a number of plant tissues were examined. The respiration of root or other tissue was measured at 25/sup 0/C by standard manometric techniques in a ratio of 95% CO and 5% O/sub 2/. The respiration of all eleven tissues studied was strongly inhibited by carbon monoxide. In ten of the eleven cases examined the inhibition was largely or completely eliminated by irradiation of the tissue with light. The evidence fairly well precludes the participation of a tyrosinase and definitely supports the participation of a cytochrome oxidase in respiration. 5more » references, 1 table.« less