By measuring chlorophyll fluorescence parameters, composition of fatty acids, active oxygen species and activities ofsome antioxidant enzymes, effects of chilling stress (4C) in the low light (100 mmol m-2 s-1) on chi...By measuring chlorophyll fluorescence parameters, composition of fatty acids, active oxygen species and activities ofsome antioxidant enzymes, effects of chilling stress (4C) in the low light (100 mmol m-2 s-1) on chilling-sensitive plants werestudied. After 6 h chilling stress (4C) in the low light, the maximal photochemical efficiency of PSII (Fv/Fm) of sweetpepper leaves decreased by 35.6%, and the oxidizable P700 decreased by 60%. However, chilling stress in the dark had noeffect on both of them. Unsaturation of fatty acids in thylakoid membrane was accelerated, which might be helpful tostabilize photosynthetic apparatus. Distortion and swelling of grana caused by chilling in the dark probably decreasedactivities of antioxidant enzymes, which resulted in the accumulation of active oxygen species. On the contrary,photooxidation might be related to the disintegration and unstacking of grana. Chilling stress induced photoinhibition ofPSII and PSI, and active oxygen species might be one of the factors causing the decrease of the oxidizable P700. PSIseemed to be more sensitive to chilling stress in the low light than PSII.展开更多
基金supported by the State Key Basic Research and Development Plan of China(G1998010100)the National Natural Science Foundation of China(30370854)the open project of Key Lab of Crop Biology of Shandong Province,P.R.China
文摘By measuring chlorophyll fluorescence parameters, composition of fatty acids, active oxygen species and activities ofsome antioxidant enzymes, effects of chilling stress (4C) in the low light (100 mmol m-2 s-1) on chilling-sensitive plants werestudied. After 6 h chilling stress (4C) in the low light, the maximal photochemical efficiency of PSII (Fv/Fm) of sweetpepper leaves decreased by 35.6%, and the oxidizable P700 decreased by 60%. However, chilling stress in the dark had noeffect on both of them. Unsaturation of fatty acids in thylakoid membrane was accelerated, which might be helpful tostabilize photosynthetic apparatus. Distortion and swelling of grana caused by chilling in the dark probably decreasedactivities of antioxidant enzymes, which resulted in the accumulation of active oxygen species. On the contrary,photooxidation might be related to the disintegration and unstacking of grana. Chilling stress induced photoinhibition ofPSII and PSI, and active oxygen species might be one of the factors causing the decrease of the oxidizable P700. PSIseemed to be more sensitive to chilling stress in the low light than PSII.
