Study On The Effect Of Nitrogen Fertilizer Management On The Growth And Development Rules After Anthesis And Grain Quality Of Rice

The effect of nitrogen fertilizer rate and application date on the growth and development rules after anthesis and grain qual ity of rice was studied with D xiangyou 26 .which had a lower chalkiness degree, and lower amylosc content and grain yield than that of Gangyou 22 .another cultivar used in the experiment in the field of Rice Research Insti tute of Sichuan Agricultural University .The results showed as follows: 1. The chlorophyll content, leaf area index(LAl), photosynthetic potential, effective ears number per hm" .grain number per ear and grain weight per ear of treatment of medium N-fertil i'/er rate(153. 3kg/hm"') were higher than those of treatment of low N-fertilizer rate(76. 7kg/hm"), so grain yield of treatment of medium N-fertilizer rate was higher than that of treatment of low N-ferti 1 izer rate. The chlorophyll content, leaf area index(LAI), photosynthetic potential of treatment of high N-fertilizer rate(230kg/hm") was higher than those of treatment of medium N-ferti 1 izer rate, but the grain number per ear, weight per 1000 grain and fertilized grains and fertilized grain-filling percentage of treatment of high N-fertilizer rate was lower than those of treatment of medium N-fertilizer rate, so the yield of treatment of high N-fertilizer rate was lower than that of treatment of medium N-fertilizer rate. The chlorophyll content, leaf area index(LAI),photosynthetic potential, photosynthetic productive ability, grain number per ear, weight per 1000 grain and harvest index of the treatment of nitrogen fertilizer applied later-date-emphasized (basic fertilizer + ear-grained fertilizer) of Gangyou 22 and D xiangyou 26 were higher than those of treatment of nitrogen fertilizer applied earlier-date-emphasized (basic fertilizer + filler fertilizer), so the yield of the treatment of nitrogen fertilizer applied later-date-emphasized washigher than that of two other treatment.2. With increasing of nitrogen fertilizer quality applied, rice chalkiness area of Gangyou 22 and I) xiangyou 26 increased accordingly, and this rule was in accordance with the increasing of activity of starch synthase .ADPglucosc pyrophosphorylase and Q-en/yme while nitrogen ferti1izer rate applied increased. As nilrogen quality applied ineresed, chalkiness degree of Gangyou 22 increased, but that of I) xiangyou 26 reduced on the contrary. The treatment of nitrogen applied later-dale-emphasized could reduce chalky rice percentage .chalkiness area and degree.3. With increasing of nitrogen fert i 1 i/er rate appl ied, acti vi ty of starch synthase , ADPglucose pyrophosphorylase and Q-enzyme of grain increased, too. The activity of ADPglucose pyrophosphorylase and Q-enzyme of grain of treatment of nitrogen fertilizer applied later-date-emphasized was higher than that of two other treatment, so the content of amylopectin and total starch of treatment of nitrogen fertilizer applied later-date-cmphasized was higher than that of two other treatment accordingly, too. The treatment of nitrogen fertilizer applied earlier-date-emphasized could increase the content of amylose of grain.