Abstract
The basis of the increased resistance to photoinhibition upon growth at low temperature was investigated. Photosystem II (PSII) excitation pressure was estimated in vivo as 1 - qp (photochemical quenching). We established that Chlorella vulgaris exposed to either 5[deg]C/150 [mu]mol m-2 s-1 or 27[deg]C/2200 [mu]mol m-2 s-1 experienced a high PSII excitation pressure of 0.70 to 0.75. In contrast, Chlorella exposed to either 27[deg]C/150 [mu]mol m-2 s-1 or 5[deg]C/20 [mu]mol m-2 s-1 experienced a low PSII excitation pressure of 0.10 to 0.20. Chlorella grown under either regime at high PSII excitation pressure exhibited: (a) 3-fold higher light-saturated rates of O2 evolution; (b) the complete conversion of PSII[alpha] centers to PSII[beta] centers; (c) a 3-fold lower epoxidation state of the xanthophyll cycle intermediates; (d) a 2.4-fold higher ratio of chlorophyll a/b; and (e) a lower abundance of light-harvesting polypeptides than Chlorella grown at either regime at low PSII excitation pressure. In addition, cells grown at 5[deg]C/150 [mu]mol m-2 s-1 exhibited resistance to photoinhibition comparable to that of cells grown at 27[deg]C/2200 [mu]mol m-2 s-1 and were 3- to 4-fold more resistant to photoinhibition than cells grown at either regime at low excitation pressure. We conclude that increased resistance to photoinhibition upon growth at low temperature reflects photosynthetic adjustment to high excitation pressure, which results in an increased capacity for nonradiative dissipation of excess light through zeaxanthin coupled with a lower probability of light absorption due to reduced chlorophyll per cell and decreased abundance of light-harvesting polypeptides.
Full Text
The Full Text of this article is available as a PDF (1.3 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Demmig B., Winter K., Krüger A., Czygan F. C. Zeaxanthin and the Heat Dissipation of Excess Light Energy in Nerium oleander Exposed to a Combination of High Light and Water Stress. Plant Physiol. 1988 May;87(1):17–24. doi: 10.1104/pp.87.1.17. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dunn S. D. Effects of the modification of transfer buffer composition and the renaturation of proteins in gels on the recognition of proteins on Western blots by monoclonal antibodies. Anal Biochem. 1986 Aug 15;157(1):144–153. doi: 10.1016/0003-2697(86)90207-1. [DOI] [PubMed] [Google Scholar]
- Maxwell D. P., Falk S., Trick C. G., Huner NPA. Growth at Low Temperature Mimics High-Light Acclimation in Chlorella vulgaris. Plant Physiol. 1994 Jun;105(2):535–543. doi: 10.1104/pp.105.2.535. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith B. M., Morrissey P. J., Guenther J. E., Nemson J. A., Harrison M. A., Allen J. F., Melis A. Response of the Photosynthetic Apparatus in Dunaliella salina (Green Algae) to Irradiance Stress. Plant Physiol. 1990 Aug;93(4):1433–1440. doi: 10.1104/pp.93.4.1433. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tsang V. C., Peralta J. M., Simons A. R. Enzyme-linked immunoelectrotransfer blot techniques (EITB) for studying the specificities of antigens and antibodies separated by gel electrophoresis. Methods Enzymol. 1983;92:377–391. doi: 10.1016/0076-6879(83)92032-3. [DOI] [PubMed] [Google Scholar]