亚种间重穗型杂交稻穗颈维管束与穗部性状的关系

The relations between panicle characters of intersubspecific heavy panicle hybrid rice and vascular bundles in neck panicle

本文对亚种间重穗型杂交稻穗颈维管束特征及籽粒充实进行了研究。结果表明 :亚种间重穗型组合的维管束数目、单个维管束面积、维管束总面积、韧皮部总面积、木质部总面积均明显高于品种间杂交稻汕优 63,从而促进了二次枝梗数、二次枝梗籽粒数的大量增加 ,这是其大穗的生物学基础 ;亚种间重穗型组合的维管束颖花负荷量及韧皮部的籽粒充实物的日流量的负荷量均低于汕优 63,因而不仅其穗大 ,而且籽粒充实良好 ,单穗重提高 ,克服了籼粳亚种间杂交稻穗大而流不畅导致籽粒充实度差这一主要生理障碍 ;

The characters of vascular bundle in neck panicle and grain filling of intersubspecific heavy panicle hybrid rice (IHPHR) were studied. The results were as follows: The IHPHR had more vascular bundles, much larger areas of single vascular bundle, much larger areas of all vascular bundles, much larger areas of all phloem and much larger areas of all xylem in neck panicle than intervarietial hybrid rice (IHR), which increased the number of the second branches and the number of grains in second branch and enlarged the panicle of IHPHR. IHPHR had a lower burdened capacity of spikelet number and matter to fill the grains in the conducting tissue than IHR. So, IHPHR had not only larger panicle but also normal grain filling and heavier panicle. IHPHR overcame the main physiological barriers of intersubspecific hybrid rice-large panicle but limited flow of photosynthetic product to the panicle that led to poor grain plumpness. The results also indicated that the breeding of IHPHR was a effective measure for the rice breeding of super high yield.