以超级稻甬优12为材料,于水稻抽穗后3 d 喷施3．2％赤霉素•多效唑(俗名粒粒饱,LLB),分析3．2％赤霉素•多效唑对超级稻甬优12产量形成的影响,并探讨其作用途径.研究表明,3．2％赤霉素•多效唑可在一定程度上提高水稻产量,2012－2013年的实际产量比对照(CK)分别高4．41％和4．31％,理论产量比对照分别高9．21％和6．26％.结实率和千粒重的增加是3．2％赤霉素•多效唑提高超级稻甬优12产量的主要因素.3．2％赤霉素•多效唑处理的结实率分别比对照高9．94％(2012年)和4．46％(2013年),而柱头花粉粒萌发率的提高是结实率增加的主要原因,因为和对照相比,3．2％赤霉素•多效唑处理对水稻花粉粒育性及柱头花粉粒数的影响不大,处理间差异不显著,但其柱头花粉萌发率显著高于对照.与对照相比,3．2％赤霉素•多效唑处理的千粒重分别增加0．39 g(2012年)和0．46 g(2013年),尤其弱势粒,其粒重增幅明显大于强势粒.此外,研究还表明,3．2％赤霉素•多效唑处理的剑叶叶绿素含量、光合速率及叶片比叶重在籽粒灌浆后期高于对照,而其籽粒和叶片可溶性糖含量比值低于对照,表明3．2％赤霉素•多效唑不仅可延缓叶片衰老,还可以促进光合同化物(可溶性糖)向籽粒转运.%In order to improve spikelet fertility and grain weight of inferior spikelets in super rice,3.2% GA3 •PP3 3 3 (Lilibao,LLB)were sprayed on super rice Yongyou 12 three days after heading.We investigated the effect of LLB on grain yield and the underlying mechanisms.The results indicated that LLB increased the grain yield by 4.41 % and 4.3 1 % in 2012 and 201 3,respectively compared to corresponding controls,while the theoretical yield showed 9.21 %and 6.26% increment.This may be ascribed to increased seed-setting rate and grain weight under LLB treatment compared with the control.It had been observed that there was no significant difference in pollen viability and pollen numbers on stigma between the LLB treatment and control,while the LLB treatment significantly increased the pollen germination on stigma,which was responsible for the improvement in seed-setting rate.Additionally,the chlorophyll content,net photosynthetic rate and specific leaf weight of flag leaf in the LLB treatment were higher,while the ratios of soluble sugar content in leaf to grain were lower than those of the control in the late grain filling period,indicating that LLB could not only delay the leaf senescence but also promote transportation of assimilates to grains.
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