Effect of High Temperature Stress on Rice Spikelet Differentiation and Degeneration during Panicle Initiation Stage
Pot experiments were conducted under artificial climate chambers conditions to assess the effect of high temperature stress on rice spikelet differentiation and degeneration during panicle initiation stage. Twoindica rice cultivars with different heat-tolerance levels, ‘Huanghuazhan’ (heat-tolerant) and ‘Fengliangyou6’ (heat-sensitive), were subjected to treatments in artificial climate chambers for 7 days of high temperature stress (40℃,10:00-15:00) and natural temperature(32℃, 10:00-15:00) at four different periods as follows: bud differentiation stage (I), branch and floret differentiation stage (II), spikelet differentiation to pistil-stamen formation stage (Ⅲ), pistil-stamen formation to pollen meiosis stage (Ⅳ), meanwhile the rice grown in ambient was as CK. The results indicated that, (1)high temperature stress increased the number of panicle initiation day, delayed rice heading date, and significantly reduced panicle weight, grain number per panicle,seed-setting rate and 1000-grain weight, especially at periodⅣ, there were more reduction in ‘Fengliangyou6’ than in ‘Huanghuazhan’.(2)Spikelet differentiation and degeneration exerted significance difference among treatments of four periods, high temperature stress reduce the number of spikelet differentiation at periodsⅠandⅡ, but ‘Huanghuazhan’'s spikelet differentiation number increased after treating at periodⅡ. High temperature tress significantly increased the ratio of spikelet degeneration of two cultivars at periodⅢ andⅣ , especially it was up to 67% at periodⅣ, and the ratio of spikelet degeneration of‘Fengliangyo6’ was higher than ‘Huanghuazhan’. (3) Spikelet differentiation and degeneration on secondary branches were more seriously affected by high temperature than primary branches.
RiceDifferent periodsHigh temperature stressSpikelet differentiation and degeneration
NETL
NSTL
万方数据
维普
