Effect of Cytokinins on the Growth of Rice Tiller Buds and the Expression of the Genes Regulating Rice Tillering

【Objective】 The objective of the present study was to investigate the relationship of cytokinins(CTK) and the expression of the genes regulating rice tillering during the regulating the growth of rice tiller buds growth and the underlying molecular mechanisms.【Method】 In the present study,a cultivar Nanjing 44 was used.At tillering stage,40 mg?L-1 nitrogen(N) was used to stimulate the germination of tiller buds.At the same time,external IAA was used to inhibit the germination of tiller buds.The changes of CTK contents in tiller buds and tiller nodes and the expression of OsTB1,OsD3,OsD10 and OsD27 in tiller buds were measured.【Result】 The external 40 mg?L-1 N increased the CTK contents in tiller nodes and tiller buds,inhibited the expression of OsTB1,OsD3,OsD10 and OsD27 in tiller buds,and then promoted the growth of rice tiller buds.However,the external application of IAA reversed the effect of N.Besides this,the expression of OsTB1 in tiller buds was regulated by CTK,however,the expression of OsD3,OsD10 and OsD27 in tiller buds might not be regulated by CTK.【Conclusion】 The results showed that external N and IAA might have regulated tiller bud growth by at least two means: one is regulating the CTK content and the expression level of OsTB1 in tiller buds,another is regulating the expression level of OsD3,OsD10 and OsD27 in tiller buds and by this to regulate the tiller bud growth.