This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Chetti, M. B. Articles by Nobel, P. S. Search for Related Content PubMed PubMed Citation Articles by Chetti, M. B. Articles by Nobel, P. S. Agricola Articles by Chetti, M. B. Articles by Nobel, P. S.

Environmental and Stress Physiology

High-Temperature Sensitivity and Its Acclimation for Photosynthetic Electron Transport Reactions of Desert Succulents ¹

Department of Biology, University of California, Los Angeles, California 90024, Laboratory of Biomedical and Environmental Sciences, University of California, Los Angeles, California 90024

Photosynthetic electron transport reactions of succulent plants from hot deserts are able to tolerate extremely high temperatures and to acclimate to seasonal increases in temperature. In this study, we report the influence of relatively long, in vivo, high-temperature treatments on electron transport reactions for two desert succulents, Agave deserti and Opuntia ficus-indica, species which can tolerate 60°C. Whole chain electron transport averaged 3°C more sensitive to a 1-hour high-temperature treatment than did PSII (Photosystem II) which in turn averaged 3°C more sensitive than did PSI. For plants maintained at day/night air temperatures of 30°C/20°C, treatment at 50°C caused these reactions to be inhibited an average of 39% during the first hour, an additional 31% during the next 4 hours, and 100% by 12 hours. Upon shifting the plants from 30°C/20°C to 45°C/35°C, the high temperatures where activity was inhibited 50% increased 3°C to 8°C for the three electron transport reactions, the half-times for acclimation averaging 5 days for A. deserti and 4 days for O. ficus-indica. For the 45°C/35°C plants treated at 60°C for 1 hour, PSI activity was reduced by 54% for A. deserti and 36% for O. ficus-indica. Acclimation leads to a toleration of very high temperatures without substantial disruption of electron transport for these desert succulents, facilitating their survival in hot deserts. Indeed, the electron transport reactions of these species tolerate longer periods at higher temperatures than any other vascular plant so far reported.

¹ Supported by the Ecological Research Division of the Department of Energy, Contract DE-AC03-76-SF00012.

This article has been cited by other articles:

				U. LUTTGE Ecophysiology of Crassulacean Acid Metabolism (CAM) Ann. Bot., June 1, 2004; 93(6): 629 - 652. [Abstract] [Full Text] [PDF]