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通过分析结实期土壤水分亏缺对水稻(Oryza sativa)籽粒中蔗糖向淀粉合成的生理代谢中关键酶活性及籽粒灌浆的调节作用,探讨土壤水分亏缺影响水稻籽粒灌浆的生理机制。结果表明,适度土壤水分亏缺诱导了灌浆高峰期(花后15-20天)水稻籽粒中蔗糖合成酶、腺苷二磷酶葡萄糖焦磷酸化酶、可溶性淀粉合成酶及淀粉分支酶活性的增加,提高了籽粒灌浆中前期(花后10-20天)籽粒中淀粉积累速率和籽粒灌浆速率。但在灌浆后期(花后20-30天)籽粒中,上述关键酶活性下降较快,籽粒活跃灌浆期明显缩短,灌浆前中期灌浆速率的增加不能完全补偿灌浆期缩短带来的同化物积累损失,导致水分亏缺处理水稻籽粒充实不良,结实率、籽粒重和产量显著降低。研究认为,灌浆期土壤水分亏缺引起的灌浆后期籽粒中蔗糖向淀粉合成代谢中一些关键酶活性快速下降和籽粒内容物的供应不足是籽粒淀粉积累总量减少、粒重降低的主要生理原因。
By analyzing the effects of soil water deficit during the grain filling stage on the key enzyme activities and grain filling in sucrose to starch synthesis in rice (Oryza sativa), the physiological mechanism of soil water deficit on rice grain filling was explored. The results showed that moderate soil water deficit induced the increase of sucrose synthase, adenosine diphosphate gluco-pyrophosphorylase, soluble starch synthase and starch branching enzyme activity in rice grain at the peak filling stage (15-20 days after anthesis) , Which increased the starch accumulation rate and grain filling rate in pre-stage (10-20 days after anthesis) grain filling. However, during the late filling stage (20-30 days after anthesis), the above-mentioned key enzyme activity decreased rapidly and the active grain filling stage shortened obviously. The increase of filling rate before filling could not completely compensate the loss of assimilation accumulation caused by the shortening filling period , Resulting in poor water-deficit treatment of rice grains, poor seed setting rate, grain weight and yield. The results showed that some of the key enzyme activities of sucrose to starch synthesis and metabolism and the deficient supply of grain contents were the main physiological reasons for the decrease of total starch accumulation and grain weight in grain filling stage.