skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: O/sub 2/-insensitive photosynthesis in C/sub 3/ plants: its occurrence and a possible explanation. [Phaseolus vulgaris; Xanthium strumarium L. ; Scrophularia desertorum (Shaw. ) Munz]

Abstract

Leaves of C/sub 3/ plants which exhibit a normal O/sub 2/ inhibition of CO/sub 2/ fixation at less than saturating light intensity were found to exhibit O/sub 2/-insensitive photosynthesis at high light. This behavior was observed in Phaseolus vulgaris L., Xanthium strumarium L., and Scrophularia desertorum (Shaw.) Munz. O/sub 2/-insensitive photosynthesis has been reported in nine other C/sub 3/ species and usually occurred when the intercellular CO/sub 2/ pressure was about double the normal pressure. A lack of O/sub 2/ inhibition of photosynthesis was always accompanied by a failure of increased CO/sub 2/ pressure to stimulate photosynthesis to the expected degree. O/sub 2/-insensitive photosynthesis also occurred after plants had been water stressed. Under such conditions, however, photosynthesis became O/sub 2/ and CO/sub 2/ insensitive at physiological CO/sub 2/ pressures. Postillumination CO/sub 2/ exchange kinetics showed that O/sub 2/ and CO/sub 2/ insensitivity was not the result of elimination of photorespiration. It is proposed that O/sub 2/ and CO/sub 2/ insensitivity occurs when the concentration of phosphate in the chloroplast stroma cannot be both high enough to allow photophosphorylation and low enough to allow starch and sucrose synthesis at the rates required by the rest of the photosynthetic component processes. Undermore » these conditions, the energy diverted to photorespiration does not adversely affect the potential for CO/sub 2/ assimilation.« less

Authors:
Publication Date:
Research Org.:
Desert Research Institute, Reno, Nevada
OSTI Identifier:
5022641
DOE Contract Number:
FG08-84ER13234
Resource Type:
Journal Article
Resource Relation:
Journal Name: Plant Physiol.; (United States); Journal Volume: 78:1
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; OXYGEN; BIOLOGICAL EFFECTS; PHOTOSYNTHESIS; INHIBITION; VISIBLE RADIATION; RESPONSE MODIFYING FACTORS; CARBON DIOXIDE FIXATION; CHLOROPLASTS; EXPERIMENTAL DATA; GAS FLOW; LEAVES; PHOSPHATES; RESPIRATION; WATER; CELL CONSTITUENTS; CHEMICAL REACTIONS; DATA; ELECTROMAGNETIC RADIATION; ELEMENTS; FLUID FLOW; HYDROGEN COMPOUNDS; INFORMATION; NONMETALS; NUMERICAL DATA; OXYGEN COMPOUNDS; PHOSPHORUS COMPOUNDS; PHOTOCHEMICAL REACTIONS; RADIATIONS; SYNTHESIS; 550501* - Metabolism- Tracer Techniques

Citation Formats

Sharkey, T.D. O/sub 2/-insensitive photosynthesis in C/sub 3/ plants: its occurrence and a possible explanation. [Phaseolus vulgaris; Xanthium strumarium L. ; Scrophularia desertorum (Shaw. ) Munz]. United States: N. p., 1985. Web.
Sharkey, T.D. O/sub 2/-insensitive photosynthesis in C/sub 3/ plants: its occurrence and a possible explanation. [Phaseolus vulgaris; Xanthium strumarium L. ; Scrophularia desertorum (Shaw. ) Munz]. United States.
Sharkey, T.D. 1985. "O/sub 2/-insensitive photosynthesis in C/sub 3/ plants: its occurrence and a possible explanation. [Phaseolus vulgaris; Xanthium strumarium L. ; Scrophularia desertorum (Shaw. ) Munz]". United States. doi:.
@article{osti_5022641,
title = {O/sub 2/-insensitive photosynthesis in C/sub 3/ plants: its occurrence and a possible explanation. [Phaseolus vulgaris; Xanthium strumarium L. ; Scrophularia desertorum (Shaw. ) Munz]},
author = {Sharkey, T.D.},
abstractNote = {Leaves of C/sub 3/ plants which exhibit a normal O/sub 2/ inhibition of CO/sub 2/ fixation at less than saturating light intensity were found to exhibit O/sub 2/-insensitive photosynthesis at high light. This behavior was observed in Phaseolus vulgaris L., Xanthium strumarium L., and Scrophularia desertorum (Shaw.) Munz. O/sub 2/-insensitive photosynthesis has been reported in nine other C/sub 3/ species and usually occurred when the intercellular CO/sub 2/ pressure was about double the normal pressure. A lack of O/sub 2/ inhibition of photosynthesis was always accompanied by a failure of increased CO/sub 2/ pressure to stimulate photosynthesis to the expected degree. O/sub 2/-insensitive photosynthesis also occurred after plants had been water stressed. Under such conditions, however, photosynthesis became O/sub 2/ and CO/sub 2/ insensitive at physiological CO/sub 2/ pressures. Postillumination CO/sub 2/ exchange kinetics showed that O/sub 2/ and CO/sub 2/ insensitivity was not the result of elimination of photorespiration. It is proposed that O/sub 2/ and CO/sub 2/ insensitivity occurs when the concentration of phosphate in the chloroplast stroma cannot be both high enough to allow photophosphorylation and low enough to allow starch and sucrose synthesis at the rates required by the rest of the photosynthetic component processes. Under these conditions, the energy diverted to photorespiration does not adversely affect the potential for CO/sub 2/ assimilation.},
doi = {},
journal = {Plant Physiol.; (United States)},
number = ,
volume = 78:1,
place = {United States},
year = 1985,
month = 1
}
  • The sensitivity of photosynthesis to O/sub 2/ and CO/sub 2/ was measured in leaves from field grown plants of six species (Phaseolus vulgaris, Capsicum annuum, Lycopersicon esculentum, Scrophularia desertorum, Cardaria draba, and Populus fremontii) from 5/sup 0/C to 35/sup 0/C using gas-exchange techniques. In all species but Phaseolus, photosynthesis was insensitive to O/sub 2/ in normal air below a species dependent temperature. CO/sub 2/ insensitivity occurred under the same conditions that resulted in O/sub 2/ insensitivity. A complete loss of O/sub 2/ sensitivity occurred up to 22/sup 0/C in Lycopersicon but only up to 6/sup 0/C in Scrophularia. In Lycopersiconmore » and Populus, O/sub 2/ and CO/sub 2/ insensitivity occurred under conditions regularly encountered during the cooler portions of the day. Because O/sub 2/ insensitivity is an indicator of feedback limited photosynthesis, these results indicate that feedback limitations can play a role in determining the diurnal carbon gain in the field. At higher partial pressures of CO/sub 2/ the temperature at which O/sub 2/ insensitivity occurred was higher, indicating that feedback limitations in the field will become more important as the CO/sub 2/ concentration in the atmosphere increases.« less
  • The sensitivity of photosynthesis to O/sub 2/ and CO/sub 2/ was measured in field grown plants of six species (Phaseolus vulgaris, Capsicum annum, Lycopersicon esculentum, Scrophularia desertorum, Cardaria draba and Populus Fremontii) from 5/sup 0/C to 35/sup 0/C. Photosynthesis was insensitive to O/sub 2/ in normal air below a species dependent temperature. CO/sub 2/ insensitivity occurred under the same conditions that resulted in O/sub 2/ insensitivity. A complete loss of O/sub 2/ sensitivity was observed up to 22/sup 0/C (in Lycopersicon) but only up to 6/sup 0/C (in Scrophularia). In Lycopersicon and Populus, O/sub 2/ and CO/sub 2/ insensitivity occurredmore » under conditions regularly encountered during the cooler portions of the day. The authors believe that O/sub 2/ insensitivity is an indicator of feedback limited photosynthesis, and that these results indicate that feedback limitations can play a role in determining plant carbon gain in the field. At higher partial pressures of CO/sub 2/ the temperature at which O/sub 2/ insensitivity occurred was higher, indicating that feedback limitations in the field will become more important as the CO/sub 2/ concentration in the atmosphere increases.« less
  • Among the four uppermost leaves of greenhouse-grown plants of Xanthium strumarium L., the content of abscisic acid per unit fresh or dry weight was highest in the youngest leaf and decreased gradually with increasing age of the leaves. Expressed per leaf, the second youngest leaf was richest in ABA; the amount of ABA per leaf declined only slightly as the leaves expanded. Transpiration and stomatal conductance were negatively correlated with the ABA concentration in the leaves; the youngest leaf lost the least amount of water. This correlation was always very good if the youngest leaf was compared with the oldermore » leaves but not always good among the older leaves. Since stomatal sensitivity to exogenous (+-)-ABA was the same in leaves of all four age groups ABA may be in at least two compartments in the leaf, one of which is isolated from the guard cells. The ability to synthesize ABA in response to wilting or chilling was strongly expressed in young leaves and declined with leaf age. There was no difference between leaves in their content of the metabolites of ABA, phaseic, and dihydrophaseic acid, expressed per unit weight.« 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
  • Amino acid incorporation into protein by cholorplasts from primary leaves of Phaseolus vulgaris L., var. Black Valentine is only partially inhibited by 400 ..mu..g/ml ribonuclease. The rate of incorporation, in the presence of ribonuclease, is progressively inhibited with time and ceases after about half an hour. Preincubation of chloroplasts at 25/sup 0/, in the absence of ribonuclease, increases the inhibitory effect of ribonuclease on the initial rate of incorporation of amino acid into protein. Examination of electron micrographs of freshly prepared chloroplast suspensions shows that chloroplasts are largely intact. However, after incubation at 25/sup 0/ for 1 hour the chloroplastsmore » are disrupted, as indicated by loss of their stroma contents. It is concluded that the intact chloroplast membrane is relatively impermeable to ribonuclease. Amino acid incorporating activity probably becomes inhibited as the inside of the chloroplast is made accessible to ribonuclease by breakage of membranes during incubation at 25/sup 0/. 17 references, 5 figures, 2 tables.« less