Regulatory Effects of Nitrogen Nutrient and 6-BA on Winter Wheat Suffered Post-anthesis Waterlogging

Waterlogging is a main stress factor during late growing period of winter wheat(Triticum aestivum L.) in Huanghuai southern and Yangtze Valley region of China.In order to alleviate waterlogging,the split block design experiment was carried out with wheat variety 'Yannong 19' to study regulatory effects of nitrogen nutrient and 6-BA on waterlogging resistance of winter wheat.The results showed that:(1)Post-anthesis waterlogging significantly reduced root system activity,root total absorbing area,root actively absorbing area,chlorophyll content(SPAD reading) of flag leaf,photosynthetic rate(Pn) of flag leaf of winter wheat and highly significantly reduced grain number per spike,1000-grain weight and yield of winter wheat,but had no significant effect on spike number.(2)Treatments of foliar spraying nitrogen nutrient+6-BA,nitrogen nutrient,6-BA,all could significantly improve waterlogging resistance of winter wheat and improved root system activity by 18.7%,14.6%,12.0%,respectively;root total absorbing area by 31.9%,22.1%,19.6%,respectively;root actively absorbing area by 32.5%,21.7%,18.1%,respectively;chlorophyll content(SPAD reading) of flag leaf by 16.2%,9.4%,10.3%,respectively;photosynthetic rate(Pn) of flag leaf by 32.6%,23.3%,23.3%,respectively;grain number per spike by 13.8%,9.3%,8.5%,respectively;1000-grain weight by 17.3%,11.5%,10.5%,respectively;and grain yield by 35.9%,23.5%,20.9%,respectively;while all had no significant effect on spike number.In summary,there were significant positive interactions between nitrogen nutrient and 6-BA.Considered comprehensively,foliar spraying nitrogen nutrient and 6-BA simultaneously was recommended to alleviate negative effects of post-anthesis waterlogging in production.