Effects of selenium and 6-BA on leaf senescence and active oxygen metabolism in grape

【Objective】To investigate the effects of selenium and 6-BA on leaf senescence and active oxy-gen metabolism in order to provide a theoretical basis for preventing leaves from early aging.【Methods】The two grape varieties Italia and Centenial seedless with different senescence-types cultured in protect-ed and delayed cultivation system were studied. Amino acid selenium and 6-BA were sprayed on thegrape leaves with equivalent clean water as control(CK).The physiological indexes of their leaves,suchas chlorophyll contents and net photosynthetic rate,superoxide radical and hydrogen peroxide contents,malondialdehyde accumulation,superoxide dismutase,peroxidase and catalase activities were deter-mined during natural senescence.【Results】Compared with control(CK),exogenous amino acid seleniumand 6- BA delayed the decrease of chlorophyll content and net photosynthetic rate significantly,in-creased the superoxide dismutase,catalase and peroxidase activities,decreased the content of malondial-dehyde,superoxide radical and hydrogen peroxide and postponed the senescence of functional leaves.There were differences between different senescence-types of grape leaves,the leaves of Italia aged slow-er and antioxidant enzymes maintained higher activities at the late growth stage.【Conclusion】The results indicated that the application of amino acid selenium and 6-BA effectively improved the leaf anti-agingproperties and prolonged the functional period of the leaves.