疏花对大穗型粳稻弱势籽粒灌浆充实及物质运转的影响

Effect of Spikelet-removing on Filling of Inferior Spikelets and Assimilates Transportation

为了充分挖掘高产水稻品种的产量潜力,以大穗型粳稻品种新稻25和郑稻18为材料进行盆栽试验,在齐穗期进行疏花处理,分析花后10、20、30d疏花处理对弱势籽粒粒重、结实率和顶一、二叶、茎、鞘中可溶性糖及淀粉含量的影响。结果表明:疏花处理后两品种的弱势籽粒粒重及结实率均得到显著提高,可能是通过提高弱势籽粒中蔗糖含量,蔗糖作为信号物质,进而调节蔗糖-淀粉代谢关键酶基因及其活性来实现的,但弱势籽粒粒重仍不同程度地低于对照强势籽粒,说明同化物供应不是限制弱势籽粒灌浆充实的唯一原因。在疏花处理后,新稻25和郑稻18的叶、茎、鞘中可溶性糖及淀粉含量基本上都高于对照,可能是由于疏花处理后库容减少,光合产物需求降低,进而导致叶、茎、鞘中积累的同化物增加所致。

n order to fully excarate yield potential of rice high-yielding varieties, taking two varieties Xindao25 and Zhengdao18 with big japonica as materials, the effect of spikelet-removing on the grain weight, seed setting rate of inferior spikelets,soluble sugar and starch content in leaf, stem and sheath of the first and second leaf position were investigated at 10,20,30 days after flowering. The results showed that the inferior grain weight and seed setting rate were increased significantly. However, the grain weight of inferior spikelets was still slightly lower than the grain weight of superior spikelets in the control,it indicated that carbon assimilates was not the only reasons why inferior spikelets filling slower. The soluble sugar and starch content in almost all of the leaf,stem and sheath at different leaf position increased,it was possible because of spikelet-removing treat- ment could reduce the photosynthesis products in leaf caused by lower sink size, leading to increase accumula- tion of assimilates in the leaf, stem and sheath.