Influence of photoinhibition on photosynthesis and lipid peroxidation

Abstract

The effect of photoinhibition at 10 and 30 °C on photosynthetic electron transport, chlorophyll fluorescence and peroxidation of thylakoid lipids was studied in intact leaves, isolated chloroplasts and photosystem (PS) II and I particles. Photoinhibition impaired the photochemistry of PS II, whose activity was more significantly affected than that of PS I. The extent of the damage was greater at 30 °C than at 10 °C. Peroxidation of thylakoid lipids, measured in isolated chloroplasts and PS II particles, was also greater at 30 °C, but peroxidation of PS I particles was almost the same at the two temperatures. The recovery of thylakoid lipids and the F v/ F m ratio after 6 h of photoinhibition was complete within 12 h in intact leaves under the growth conditions.