Abstract
The effect of high temperatures on CO2 assimilation, metabolite content, and capacity for reducing power production in non-photorespiratory conditions has been assessed in two different bean (Phaseolus vulgarus L.) varieties, Blue Lake (commercially available in the United Kingdom) and Barbucho (a noncommercially bred Chilean variety), which are known to differ in their resistance to extreme high temperatures. Barbucho maintains its photosynthetic functions for a longer period of time under extreme heat compared with Blue Lake. The CO2 assimilation rate was increased by increases in temperature, with a decrease in ratio of rates of temperatures differing by 10[deg]C. It is suggested that limitations to CO2 assimilation are caused by metabolic restrictions that can be differentiated between those occurring in the range of 20 to 30[deg]C and 30 to 35[deg]C. It is likely that changes in the capacity for Calvin cycle regeneration and starch synthesis affect photosynthesis in the range of 20 to 30[deg]C. But following an increase in temperature from 30 to 35[deg]C, the supply of reducing power becomes limiting. From analysis of adenylate concentration, transthylakoid energization, and, indirectly, NADPH/NADP+ ratio, it was concluded that the limitation in the assimilatory power was due to an oxidation of the NADPH/NADP+ pool. In the range of 30 to 35[deg]C, the photosystem I quantum yield increased and photosystem II maintained its value. We conclude that the reorganization of thylakoids observed at 30 to 35[deg]C increased the excitation of photosystem I, inducing an increase in cyclic electron transport and a decrease in the supply of NADPH, limiting carbon assimilation.
Full Text
The Full Text of this article is available as a PDF (803.5 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Emmett J. M., Walker D. A. Thermal uncoupling in chloroplasts. Inhibition of photophosphorylation without depression of light-induced pH change. Arch Biochem Biophys. 1973 Jul;157(1):106–113. doi: 10.1016/0003-9861(73)90395-0. [DOI] [PubMed] [Google Scholar]
- Gerhardt R., Stitt M., Heldt H. W. Subcellular Metabolite Levels in Spinach Leaves : Regulation of Sucrose Synthesis during Diurnal Alterations in Photosynthetic Partitioning. Plant Physiol. 1987 Feb;83(2):399–407. doi: 10.1104/pp.83.2.399. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hall N. P., Keys A. J. Temperature dependence of the enzymic carboxylation and oxygenation of ribulose 1,5-bisphosphate in relation to effects of temperature on photosynthesis. Plant Physiol. 1983 Aug;72(4):945–948. doi: 10.1104/pp.72.4.945. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harbinson J., Genty B., Foyer C. H. Relationship between Photosynthetic Electron Transport and Stromal Enzyme Activity in Pea Leaves : Toward an Understanding of the Nature of Photosynthetic Control. Plant Physiol. 1990 Oct;94(2):545–553. doi: 10.1104/pp.94.2.545. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harris G. C., Cheesbrough J. K., Walker D. A. Measurement of CO(2) and H(2)O Vapor Exchange in Spinach Leaf Discs : Effects of Orthophosphate. Plant Physiol. 1983 Jan;71(1):102–107. doi: 10.1104/pp.71.1.102. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heldt W. H., Werdan K., Milovancev M., Geller G. Alkalization of the chloroplast stroma caused by light-dependent proton flux into the thylakoid space. Biochim Biophys Acta. 1973 Aug 31;314(2):224–241. doi: 10.1016/0005-2728(73)90137-0. [DOI] [PubMed] [Google Scholar]
- Holaday A. S., Martindale W., Alred R., Brooks A. L., Leegood R. C. Changes in Activities of Enzymes of Carbon Metabolism in Leaves during Exposure of Plants to Low Temperature. Plant Physiol. 1992 Mar;98(3):1105–1114. doi: 10.1104/pp.98.3.1105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ku S. B., Edwards G. E. Oxygen Inhibition of Photosynthesis: I. Temperature Dependence and Relation to O(2)/CO(2) Solubility Ratio. Plant Physiol. 1977 May;59(5):986–990. doi: 10.1104/pp.59.5.986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Monson R. K., Stidham M. A., Williams G. J., Edwards G. E., Uribe E. G. Temperature Dependence of Photosynthesis in Agropyron smithii Rydb. : I. FACTORS AFFECTING NET CO(2) UPTAKE IN INTACT LEAVES AND CONTRIBUTION FROM RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE MEASURED IN VIVO AND IN VITRO. Plant Physiol. 1982 Apr;69(4):921–928. doi: 10.1104/pp.69.4.921. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pastenes C., Horton P. Effect of High Temperature on Photosynthesis in Beans (I. Oxygen Evolution and Chlorophyll Fluorescence). Plant Physiol. 1996 Nov;112(3):1245–1251. doi: 10.1104/pp.112.3.1245. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ruban A. V., Young A. J., Horton P. Induction of Nonphotochemical Energy Dissipation and Absorbance Changes in Leaves (Evidence for Changes in the State of the Light-Harvesting System of Photosystem II in Vivo). Plant Physiol. 1993 Jul;102(3):741–750. doi: 10.1104/pp.102.3.741. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vallon O., Bulte L., Dainese P., Olive J., Bassi R., Wollman F. A. Lateral redistribution of cytochrome b6/f complexes along thylakoid membranes upon state transitions. Proc Natl Acad Sci U S A. 1991 Sep 15;88(18):8262–8266. doi: 10.1073/pnas.88.18.8262. [DOI] [PMC free article] [PubMed] [Google Scholar]