抄録
Spinach thylakoid and photosystem II membranes are vulnerable to various abiotic stresses, such as heat and strong visible light. Some of the things that result upon moderate heat stress at 40oC for 30 min are: lipid peroxidation, production of singlet oxygen, and degradation of the reaction center-binding D1 protein. These heat-induced oxidative processes were suppressed significantly when the samples were pretreated with phospholipase A2, an enzyme that hydrolyzes phosphatidylglycerol, and reappeared when phosphatidylglycerol was present. When lipoxidase was added to the photosystem II membrane, lipid peroxidation was induced and singlet oxygen production was also enhanced upon subsequent heat stress. Since phosphatidylglycerol is the sole phospholipid closely located to and tightly bound to the core of the photosystem II membrane, it is likely that peroxidation of phosphatidylglycerol triggered by endogenous lipoxydase(s) plays an important role in the oxidative damage to Photosystem II under moderate heat stress.
