籼粳亚种杂交组合的结实率与光合产物供给水平及转运效率间的关系

RELATIONSHIP BETWEEN SEED SETING RATIO AND PHOTOSYNTHETIC CAPACITY AND TRANSPORT OF SUBSTANCES INTHE INDICA-JAPONICA INTERSUBSPECIFIC HYBRID RICE

通过剪除部分颖花和部分功能叶片以及^(14)CO_2标记光合产物等处理,探讨了亚种组合结实率偏低的生理原因。结果证明:光合产物供给水平是制约亚种组合结实率的一个十分重要的因素。虽然亚种组合的叶面积指数和单株叶面积比常规籼稻大得多,但由于每穗颖花数多。以至每朵颖花占有的叶面积并无明显优势,且其光合速率低于常规籼稻,因而分配给每朵颖花的光合产物量相对减少,限制了部分颖花的发育。^(14)C光合产物分配到穗部的比率不但不低于常规籼稻,而且比其略高,说明亚种组合输导组织的运输能力不是结实率偏低的限制因素。

The physiological basis of reduced seed setting in the intersubspecific hybrid rice was investigated by partial incising of florets and function leaves and C labelling of photosynthtic products. The results clearly showed that photosynthetic capacity is the key factor determining seed setting in the intersubspecific combination. Although the leaf area index and total leaf area of individual rice plant are usually higher in the intersubspecific combinations than in conventional indica varieties, excess florets per panicle and low photosynthetic rate reduce the leaf area/floret ratio and partition of photosynthetic products to each floret, thus hinding the normal development of some filorets. Moreover, higher proportio of C-labelled photosynthetic product detectable in the panicles of intersubspecific combinations than in that of indica varieties indicates that transfusion tissue poses no restraint on the transport of substances to the floret.