Effect Of Phosphate Fertilizer On Nitrogen Absorption And Utilization And Starch Quality Of Wheat

The effects of phosphorus fertilizer on nitrogen use efficiency and starch quality of weak gluten wheat were studied in 2017-2018(ningmai13,wanximai0638)and 2018-2019(ningmai13).Two nitrogen levels(N1:120 kg/hm2,N2:180 kg/hm2)and three phosphorus levels(P2O5 level P1:60 kg/hm2,P2:120 kg/hm2,P3:180 kg/hm2)were set up to study the effects of phosphorus application on nitrogen absorption and utilization,starch grain size distribution and quality characters of wheat plants,and to analyze the differential expression genes and functions in the process of grain growth at the recording level.The test results are as follows:1.The reasonable application of P fertilizer is beneficial to the increase of grain yield.The yield of N2 was higher than that of N1.The number of ears and grains per ear of Ningmai 13 and Wanxi 0638 were significantly affected by nitrogen,and the grain weight of Ningmai 13 was significantly affected by nitrogen level.The protein content,wet gluten content and sedimentation value increased with the increase of nitrogen application level;compared with different phosphorus application levels,the increase of phosphorus application level was not conducive to the increase of protein content,wet gluten content and sedimentation value.2.The increase of P application level is beneficial to the increase of nitrogen accumulation per plant at flowering stage.Compared with different P levels,the increase of P application level significantly increased the nitrogen accumulation of plants and grains at maturity.With the increase of P application level,there was no significant difference in the amount of nitrogen transport per plant in the pre anther vegetative organs under N1 level,and with the increase of P application level under N2 level,the amount of nitrogen accumulation per plant in the pre anther vegetative organs increased first and then decreased,and there was no significant difference between n2p2 and n2p3.The transport rate and contribution rate of nitrogen from the vegetative organ to the grain were decreased by increasing the level of nitrogen and phosphorus.Nitrogen and phosphorus application increased nitrogen use efficiency decreased.The results showed that the increase of P application level significantly increased the nitrogen accumulation of plants and seeds at the mature stage,increased the nitrogen accumulation of vegetative organs and seeds immediately after flowering,and improved the nitrogen production efficiency.Nitrogen production efficiency is lower than that of N1 at N2 level,which indicates that increasing nitrogen level will reduce nitrogen production efficiency.Comparing with different phosphorus application levels,increasing nitrogen production efficiency at phosphorus application level will increase.3.With the increase of phosphorus level,the volume and surface area percentage of type a starch increased significantly,while the volume and surface area percentage of type B starch decreased significantly.It can be seen that the increase of phosphorus level is conducive to the accumulation of more A-type large starch grains.With the increase of phosphorus application level,the peak viscosity,valley viscosity,final viscosity,disintegration value and recovery value gradually increased,but the peak viscosity of high phosphorus application(P3)decreased;The increase of viscosity parameter may be related to the change of starch particle size distribution.4.The grain filling rate of Ningmai 13 showed a trend of "slow-fast-slow" after anthesis.Correlation analysis showed that there was a significant positive correlation between grain weight at maturity and time of maximum filling rate(Tmax)and filling duration(d).Reasonable application of phosphorus can improve the grain filling characteristics,prolong the duration of grain filling and delay the emergence of the maximum filling rate,which is conducive to the accumulation of more assimilates.5.On the 7th and 21st day after anthesis at N1 level,SS enzyme activity increased with the increase of P application level;on the 7th and 14th day after anthesis at N2 level,SS enzyme activity was the highest at P2 level,and on the 21st day after anthesis at N2 level,SS enzyme activity increased at P application level.The activity of AGP enzyme was higher in P2 and P3 treatments with higher P application 21 days after anthesis.The SBE activity of P2 and P3 treatment was higher than that of P1 treatment 21 days after anthesis.The results showed that the activities of SS,AGP and SBE of Ningmai 13 were higher in P2 or P3 treatment at the later stage of grain filling(21 d),which indicated that appropriate P application level could improve the activities of enzymes at the later stage of grain filling,and had a positive effect on Starch Synthesis and grain filling.6.After screening,235 differential genes were screened between P2(P application)and P0(control)on the 7th day after anthesis,among which 223 were up-regulated genes and 12 were down regulated genes.Compared with the control,96 differentially expressed genes were screened after 14 days of application of phosphorus,including 57 up-regulated genes and 39 down regulated genes.There were 1560 different genes screened by P application 21 days after anthesis,822 of which were up-regulated genes and 738 of which were down-regulated genes.The analysis of KEGG pathway showed that the pathway of amino acid biosynthesis and nitrogen metabolism reached a significant level(P<0.05)21 days after anthesis.The data showed that the application of phosphorus was not conducive to amino acid biosynthesis and nitrogen metabolism,decreased the expression of related genes,and ultimately was not conducive to the increase of protein content.