Protective Effects of Exogenous Antioxidants and Phenolic Compounds on Photosynthesis of Wheat Leaves under High Irradiance and Oxidative Stress

摘要: Infiltration of methyl viologen (MV, source O2−) and Na-diethyldithiocarbamate (DDC, inhibitor SOD) into wheat leaves resulted in the accumulation active oxygen species photo-oxidative damage to photosynthetic apparatus under both moderate high irradiance. Exogenous antioxidants, ascorbate (ASA) mannitol, scavenged efficiently, protected system from MV DDC induced oxidative damage, maintained Fv/Fm [maximal photochemical efficiency photosystem 2 (PS2) while all PS2 reaction centres are open], Fm/F0 (another expression for maximal PS2), ΦPS2 (actual quantum yield actinic irradiation), qP (photochemical quenching coefficient), PN (net rate), lowered qNP (non-photochemical coefficient) kept irradiance stress. Phenolic compounds used these experiments, catechol (Cat), resorcinol (Res), tannic acid (Tan), had similar anti-oxidative activity protective effect on as ASA mannitol. The phenolic increased with increase their concentration 100 300 g m−3. number position hydroxyl group molecules seemed influence antioxidative activity.