Research On The Physiology Mechanism Of Grain Filling Of Inferior Grain During Day And Night Chemical Regulations

With the large panicle rice cultivar of yujing6hao as the material, which grow in yellow and huaihai rive for many years, the physiological mechanism causing the inferior grains were researched by spraying three kinds of chemical regulators ABA,GA3,PR1 (the concentration is 20 mg/kg, spraying water as control) on experimental farm of Henan agricultural university from 2007 to 2010. Three or four repeatition in field experiment, the dry matter accumulation and transfer grain dimension were carried on to understand why the inferior grains had the bad grain filling. The results were followed:1 Effects of chemical regulations on yield and yield components of rice. The results showed that the treatment of ABA, GA3 and PR1 increased the yield of yujing6hao in 2007 years and 2008 years, and the differences reached the significance. The increasing of yield under ABA, GA3 and PR1 treatment was mainly through increasing the seed setting rate,1000-grain weight of superior and inferior and grain plumpness of rice.besides, PR1 treatment also increase relative grade of fiilled grain of rice. The effects of PR1 treatment were superior to ABA and GA3 treatment.2 Effects of chemical regulations on output and accumulation of non-structural carbohydrate in stem and sheath in rice. The results showed that neither sheath nor stem, the changes of soluble sugar and starch were similar at the grain filling stage. The sugar and starch outputs of top second stem and sheath were increased by ABA treatment. PR1 treatment improved mean sugar content of all stems and the outputs of sugar and starch in the top first stem and sheath, thus it could start-up the earlier grain filling.The daily changes of sugar and content in stem and sheath at different grain filling stage showed different treads. PR1 treatment increased each time conent of sugar in 28 DAA. The hightest content of starch of top second,third stem and sheath was 1:00 at grain filling stage.The sugar output size was PR1>ABA>GA3 and that of starch was ABA>GA3 >PR1 at the grain filling, besides, the greatest output were the top second,third stem and sheath at the grain filling. Treatment PRl was mainly increased the sugar output of top second stem and Treatment ABA was mainly increased the starch output at medium and late stage (from 22 to 34 DAA)3 Effects of chemical regulations on grain weight and plumpness of different posititions. The results showed 1000-grain weight and grain plumpness of superior was bigger than that of inferior at maturation stage. Except of the six grain, the othe grains were maintained the same order with the flowering sequence. The mean 1000-grain and grain plumpness was increase by the treatment and the effects were PRl>ABA>GA3. The difference between grain weight and plumpness was affected by the grains in secondary branch of inferior grains, except the first grain.The changes of grain weight at grain filling stage:the increasing of the grain weight was rapid at early and medium stage, then slowly. The difference between ABA,GA3 and CK treatment was not significant, however, PRl treatment increased the grain weight of every stage. The curve of relative grade of filled grain was "V" shaped curve. ABA and GA3 treatment increased relative grade of filled grain in 5 DAA and PR1 treatment increased that at early and late stage (from 5 to 20 DAA)The daily changes at grain filling:on the whole, the grain filling rate of day was faster than that of night at the early and medium stage (from 5 to 20 DAA); while at the medium and late stage (from 25 to 35 DAA) the the grain filling rate of nigh was faster than that of day. In the day time, the grain filling rate of 7:00-13:00 was faster than that of 13:00-19:00; at night the grain filling rate of 19:00-1:00 was faster than that of 1:00-7:00. ABA treatment increased mean inferior grain weight of all the day in 5 DAA. PR1 treatment increased average grain weight of superior and inferior of all the day at grain filling stage.4 Effects of chemical regulations on sugar content of grain. The results showed that the content of soluble sugar of inferior grain was heavier than that of superior at the grain filling stage. For most of the stage, the soluble sugar content was higher in 19:00. The daily changes of sugar content were smooth by PR1 treatment. GA3 treatment played a obvious role in increasing the sugar content at every stage, the role of ABA treatment was less.5 Effects of chemical regulations on starch accumulation of grain. The results showed that the trends of starch accumulation of superior and inferior grains were "S"-type changes, which were like the changes of grain weight. The starch accumulation of inferior grains was lower than that of superior grains. The daily change of starch accumulation was very complex, however, totally speaking, the rate of starch accumulation in the day was faster than that at night. In the day, the rate of starch accumulation in 7:00-13:00 was higher than that 13:00-19:00, at night that 19:00-1:00 was higher than 1:00-7:00.6 Effects of chemical regulations on grain storage capacity of enzyme activity. The results showed that GBSS enzyme activity of inferior was higher than AGPP and GBSS enzyme activity at the grain filling. AGPP and SSS enzyme activity showed a single peak curve, the activity of enzyme were hightest in 20 AAA. GBSS enzyme activity gradually increased during the grain filling. PR1 treatment affected AGPP enzyme activity at the early and late grain filling and it played role on SSS and GBSS enzyme activity at almost grain filling.Among three enzyme, SSS enzyme activity had a close relationship with grain plumpness of rice.20 DAA might be important stage which affected grain filling.The difference of enzyme activity was very big and each treatment on the regulation of different time points was not the same. The enzyme activity of inferior grain within a relatively short time was complex.13:00 and 19:00 might be the regulation time on AGPP and SSS enzyme activity, while 7:00 of the next day might be the regulation time on GBSS enzyme activity.7. Eeffects of chemical regulations on the endogenous IAA,ZR,GA and ABA content. The total contents of ABA and IAA were higher than those of GA3 and ZR. The change of ZR and IAA was inverted "V"-type and the highest content was in 15 DAA or 20DAA; The change of GA and ABA was "V"-type and the lowest content was in 15 DAA.Exogenous ABA and PR1 treatment had a vious effects on the endogenous hormone content and it increasesed the content of endogenous hormone content. At the grain filling stage, the daily change of endogenous ABA content had a close correlation with yield and grain plumpness and higher endogenous hormone content could increase the yield and grain plumpness.