Effect Of Waterlogging After Anthesis On Root Cap Senescence In Wheat And Its Regulation

Waterlogging is a major meteorological disaster in wheat in the middle and lower reaches of the Yangtze River.Post-anhydration waterlogging seriously affects the grain filling of wheat,resulting in a lower fertility rate,a decrease in grain weight,and ultimately affecting yield.In order to clarify the effect of post-flowering waterlogging on the growth of wheat roots and aboveground parts,the restoration and regulation of post-anthesis stained wheat were explored.The results were as follows:Ningmai 13,Yangmai 18,Wan Ken mai 076,Yannong 19 and Wanmai 52 etc.5 wheat varieties was used as the test material.Waterlogging began at the flowering stage of wheat and the duration of waterlogging was 0?W0?,3?W3?,6?W6?and 9?W9?respectively.After the waterlogging treatment,0.5%nitrogen fertilizer and 0.3%KH₂PO₄ were sprayed respectively,and distilled water was sprayed as a control.The effects of nitrogen fertilizer and KH₂PO₄ treatment on the grain yield and quality of post-contaminated wheat were investigated.The results showed that:1 Effect of waterlogging time on wheat yieldThere was no significant difference in yield and quality between W3 treatment andW0 treatment.Grain yield and quality of W6 and W9 treatments were significantly lower than W0 and W3 treatments.The main reason was that the SPAD value and net photosynthetic rate of flag leaf treated by W6 and W9 were significantly lower than other treatments,which led to a significant decrease in 1000-grain weight.Post-anthesis waterlogging significantly reduced the distribution of dry matter into grains,and W6and W9 treatments had significantly lower grain dry matter quality and economic coefficients than W0 and W3 treatments.2 Effect of waterlogging time on nitrogen metabolism in wheatThere was no significant difference in nitrogen accumulation and grain proteincomposition between W3 and W9,and W0 treatment.The nitrogen accumulation and grain protein composition of W6 and W9 treatments were significantly lower than W0and W3 treatments.The main reason was that the post-anthesis waterlogging significantly reduced the nitrogen use efficiency,resulting in a decrease in the total nitrogen accumulation of the plant,and the protein components in the W6 and W9treatments were significantly reduced,eventually leading to the accumulation of nitrogen in the W6 and W9 mature grains.Significantly lower.3 Effect of waterlogging duration on root morphology,root activity and endogenousprotective enzyme activity of wheatThe root morphology,root activity,and endogenous protective enzyme activities of wheat varieties were not significantly different from those of W0 treatment.W6 and W9treated root dry weight,root activity,catalase?CAT?and superoxide dismutase?SOD?Activity was significantly lower than that of W0 and W3 treatments.Root peroxidase?POD?activity and malondialdehyde?MDA?content of W6 and W9 treatments were significantly higher than those of W0 treatment.Waterlogging after flowering significantly reduced the root activity of wheat and the activities of CAT and SOD in roots,aggravated membrane lipid peroxidation of root cells,and accelerated root senescence.4 Effect of post-waterlogging treatment on wheat yield and qualityBoth nitrogen fertilizer spraying after applying waterlogging and KH₂PO₄ sprayingcould increase wheat yield and quality,but the yield after remediation was lower than that of W0 treatment.During W9 treatment,the yields of Ningmai 13,Yangmai 18,Wan Ken mai 076,and Yannong 19 were increased by 14.27%,14.66%,17.93%,and 13.41%,respectively,and the yields of KH₂PO₄ treatment increased.12.90%,14.81%,13.88%,18.34%.The effect of nitrogen fertilizer and KH₂PO₄ after W9 treatment was significantly higher than that after W3 and W6 treatment.5 Effect of post-waterlogging treatment on root morphology,endogenous protectiveenzymes and root activity of wheatSpraying nitrogen fertilizer and KH₂PO₄ after W3,W6 and W9 treatments had no significant effect on the average root diameter,total root volume,total root length and surface area of wheat.Spraying nitrogen fertilizer and KH₂PO₄ after W6 and W9treatments increased the dry weight of wheat roots.Spraying nitrogen fertilizer and KH₂PO₄ reduced POD activity and MDA content in wheat roots,and increased CAT,SOD activity and root activity in wheat roots.There was no significant difference in the effect of spraying N fertilizer and spraying KH₂PO₄.In summary,the post-anthesis of waterlogging in wheat will accelerate the agingprocess of roots,which will affect the growth of wheat above ground and accelerate the aging process of flag leaf,affecting the absorption and transport of nitrogen and other nutrients by wheat,and dry matter.The accumulation eventually led to a decline in wheat grain yield and quality.Spraying nitrogen fertilizer and KH₂PO₄ after waterlogging could delay the senescence of wheat and increase the yield,but it could not reach the level before waterlogging,and there was no significant difference in the effect of spraying N fertilizer and spraying KH₂PO₄.