杂交水稻两优培九强、弱势粒结实生理研究

Setting Physiology of the Superior and Inferior Grains of Hybrid Rice Liangyoupeijiu

杂交水稻两优培九抽穗当天 ,强势粒 (上部一次枝梗籽粒 )中总RNA、mRNA含量都高于弱势粒 (下部二次枝梗籽粒 )。抽穗后第 5天 ,强势粒中总RNA含量仍然高于弱势粒 ,mRNA含量两者差异不大。开花当天 (强势粒抽穗当天 ,弱势粒抽穗后第 7天 )和开花后第 5天 (强势粒抽穗后第 5天 ,弱势粒抽穗后第 12天 ) ,强势粒中总RNA、mRNA含量和单粒含量都高于弱势粒。可见强势粒比弱势粒库活性高。不论是强势粒还是弱势粒 ,从抽穗、开花到开花后第 5天 ,其总RNA、mRNA单粒含量都有显著的增加。弱势粒比强势粒胚胎发育进程较晚 ,最终胚乳细胞数也较少 ,然而细胞体积较大 ,细胞间隙也较大 ,籽粒灌浆的物理障碍较大。下部二次枝梗维管束与上部一次枝梗维管束相比导管面积和韧皮部面积较小 ,导管、筛管和伴胞分化不够 ,单个导管、筛管和伴胞面积较小 ,物质运输不畅 ,这是强、弱势粒结实率和充实度差异的原因。

In the heading day of hybrid rice Liangyoupeijiu, the contents of the total RNA, mRNA in the superior grains (upper primary branches grains) ovaries were higher than that in the inferior grains (lower secondary branches grains) ovaries.In the fifth day after heading, the contents of the total RNA in the superior grains ovaries were still higher than that in the inferior grains ovaries, the difference of the mRNA contents was not significant.In the bloom day (the heading day of superior grains, the seventh day after heading of inferior grains) and the fifth day after bloom (the fifth day after heading of superior grains, the twelfth day after heading of inferior grains), the contents of the total RNA, mRNA in the superior grains ovaries were higher than that in the inferior grains ovaries.Whether superior grains or inferior grains, the single grain contents of the total RNA, mRNA increased from heading to the fifth day after bloom.These illustrated that the activity of superior grains higher than that of inferior grains.The inferior grains developed later, their endosperms cells were fewer but bigger than that of superior grains, as a result, the interval of the endosperms were bigger, the physical obstruction to grains-filling also bigger.Vascular bundles link to the inferior grains (lower secondary branches vascular bundles) deve- loped poorer than that link to the superior grains (upper primary branches vascular bundles), its vessel, sieve tube and companion cell differentiated not enough, and the total areas of its vessel and phloem and single areas of vessel, sieve tube and companion cell were smaller.That was the reason of the differences of setting percentage and filling rate between superior grains and inferior grains.