Study On Nitrogen Regimes In Response To Quality Worsening Of Heat Stress During Wheat Grain Filling

The studies selected strong gluten J20,Y19 and G8901 as experimental material. During the late wheat grain filling (after florescence 17 to 34 days), high temperature stress was taken on. Effects of the ratio of base N and application N on grain yield and quality under high temperature stress were studied. The main results were as fellows:1,Effects of the Ratio of Base N and Application N on Grain Yield under heat stressConsidering 1000-grain weight, grain yield, biological yield and harvest index ,base N 30% and application N 70% is higer than base N 50% and application N 50%.When ratio of application N increased from 50% to 70%, the 1000-grain weight, grain yield of J20 and G8901 take on different significantly; while the difference of Y19 was not significant.2,Effects of the Ratio of Base N and Application N on nitrogen content of plant organ under heat stressBefore heat stress, the ratio of base N and application N on nitrogen content of plant organ was not significant. After 11 days and maturity under heat stress, application N increased from 50% to 70%, nitrogen content of J20 andY19 increased,while it was not significant for G8901. 3,Effects of the Ratio of Base N and Application N on Grain protein content and components under heat stressDuring the 29 days after florescence, the difference between the ration of base N and application N was not significant. During maturity, grain protein content of three wheat was significantly higher with 3:7(base N and application N) treatment than 1:1(base N and application N) treatment.When application N increased from 50% to 70% in maturity, the single protein content, insoluble and soluble protein content of J20 an Y19 increased, while G8901 had no changes.4,Effects of the Ratio of Base N and Application N on Glutenin content and components under heat stressComparison in varieties, the J20 protein content, HMW-GS and LMW-GS is the highest, followed by G8901 and Y19. Comparison between the different treatment of nitrogen, HMW-GS/LMW-GS ratio, HMW-GS and LMW-GS content of the three species performanced higher with 3:7 (ratio of base N and application N) treatment than 1:1(ratio of base N and application N) treatment.5,Effects of the Ratio of Base N and Application N on content of dissociative amino acids under heat stressBefore heat stress, nitrogen treatment had no effect on dissociative amino acids content. After heat stress, dissociative amino acids content increased when the ratio of application N increased from 50% to 70%.6,Effects of the Ratio of Base N and Application N on content of GMP under heat stressBefore heat stress, the GMP accumulation had no significant in different nitrogen treatments. After heat stress in 6 days, 11 days, 16 days, the GMP content with 3:7 (ratio of base N and application N) treatment is higer than 1:1(ratio of base N and application N)treatment.7,Effects of the Ratio of Base N and Application N on GMP/TGP under heat stress The weighted average volume and weighted average surface area of J20 and Y19 were higher with 3:7 (ratio of base N and application N) treatment than 1:1(ratio of base N and application N) treatment, while G8901 had no different in treatments.8,Effects of the Ratio of Base N and Application N on accumulation of starch content and grain components under heat stressIn maturity, grain amylose contents of J20 and Y19 performanced higher with 3:7 treatment than that 1:1 treatment, while G8901 had no different in treatments. The amylopectin contents of J20 and G8901 were higher with1:1 (ratio of base N and application N) treatment than that 3:7(ratio of base N and application N) treatment, while Y19 had no different in nitrogen treatments.9,Effects of the Ratio of Base N and Application N on Grain sugar content under heat stressAfter heat stress, soluble sugar content decreased rapidly with 1:1 treatment(ratio of base N and application N), while first elevated and reduced with 3:7 treatment(ratio of base N and application N).The total soluble sugar content with 3:7 treatment(ratio of base N and application N) was higher than 1:1 treatment(ratio of base N and application N). Sucrose content of grain was basically consistent with total soluble sugar content.10,Effects of the Ratio of Base N and Application N on process quality of flour under heat stressThe peak viscosity, low viscosity and dilute values were higher with 1:1 (ratio of base N and application N) treatment than 3:7(ratio of base N and application N) treatment.Dough time, dough stability time were higher with 3:7 (ratio of base N and application N) treatment than 1:1(ratio of base N and application N) treatment.