Under environmental stress plants and algae employ a variety of strategies to avoid damage to the photosynthetic apparatus and maintain photosynthetic capacity. To date, most studies on stress acclimation have focused on model organisms possessing limited tolerance to elevated stress levels. We compared the long-term acclimatory capacities of a mesophilic alga (Chlamydomonas raudensis SAG 49.72; SAG 49.72) and an Antarctic halotolerant psychrophile (Chlamydomonas sp. UWO 241; UWO 241) by monitoring photobiology, cyclic electron flow (CEF) and ROS defense in cultures acclimated to long-term low temperature, high salinity or high light stress. SAG 49.72 responded to long-term stress by increasing chlorophyll a/b ratio and redistributing absorbed light energy from photosystem II (PSII) to photosystem I (PSI). In contrast, the psychrophile exhibited faster half times for P700+ re-reduction under all treatments, suggesting high CEF rates. High CEF was accompanied by increased capacity for nonphotochemical quenching. Last, UWO 241 exhibited constitutively high activity of two key ascorbate cycle enzymes, ascorbate peroxidase and glutathione reductase, as well as a large ascorbate pool. Our results suggest that UWO 241 relies on high PSI-mediated CEF and ROS detoxification to protect the photosynthetic apparatus while minimizing energy expenditure on repairs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.