Effect Of Brassinosteroide (BR) On Grain Filling In Rice And Its Physiological Mechanism

We study the effect of brassinosteroide on rice grain-filling, while brassinazole was used as negative control, Both brassinosteroide and brassinazole were sprayed at Nipponbare primary flowering stage and the experiment was done in the Langfang-base of Chinese Academy of Agricultural Sciences during the year of2010and2011, We analysed the content of soluble sugar and starch, the activities of starch synthesis related enzymes, some plant hormones content and the multiplication of endosperm cell during the grain filling so as to study the the effect of BR on grain filling and its mechenism. The main results we got were as follows:1. BR improved the transportation of sucrose into grains, increased the content of soluble sugar and rate of starch accmulation and grain filling;2. BR enhanceds the activities of SuS, APGase, SSS and SBE, as well enlarged the sink during grain filling of rice, and ipromoted the transportation and degredation of sucrose in grains, increased the rate of starch synthesis and grain filling;3. BR increased the content of ABA, IAA and GA during rice grain filling, but CTK changes indistinctively, BR can also regulates the process of the rice grain filling indirectly through the changes of these phytohormones;4. BR accelerated the division rate and increases the number of endosperm cell at early grain filling, as well as increased the sink capacity and grain weight;5. On conclusion, BR can promotes the rice grain filling, setting rate and grain weight, ultimately increases the rice yield by10%around within small part assay.