Exogenous 6-benzyladenine improves antioxidative system and carbon metabolism of summer maize waterlogged in the field

A field experiment was performed to study the effects of spraying exogenous 6-benzyladenine (6-BA) after waterlogging for 6days at the third leaf stage and the sixth leaf stage on the activities of key enzymes in carbon metabolism, leaf gas exchange parameters, fluorescent characteristic, antioxidant enzymes activities and MDA content of summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958), in order to illuminate the regulations of exogenous spraying 6-BA to antioxidative system and carbon metabolism of waterlogged summer maize. Results showed that exogenous application of 6-BA effectively alleviated the adverse effects of waterlogging on carbon metabolism by improving photosynthetic characteristics and the activities of RuBPCase (in the range of 48%-81%) and PEPCase (in the range of 14%-46%). Treatments with spraying exogenous 6-BA resulted in significant and substantial increases in net photosynthetic rate (around 49%) and phi(PSII) (around 16%) compared to those of waterlogging treatments. In addition, spraying 6-BA effectively alleviated waterlogging damages on antioxidative enzyme activity and decreased MDA content, delaying leaf senescence, resulted in significant and substantial (around 19%) increases in grain yield. Visibly, spraying exogenous 6-BA effectively alleviated waterlogging damages on antioxidative system and carbon metabolism of summer maize, resulting in yield increase in waterlogged maize.