光敏核不育水稻对日照长度处理反应的叶片及部位

The Leaves and Sites for Inducing Fertility Change by Photoperiod in Photoperiod-sensitive Genic Male Sterile Rice

因具有长日照条件下雄性不育以及短日条件下可育的特性,光敏核不育水稻在两系杂交稻育种中发挥了重大作用,然而接受光周期信号决定育性转换的水稻叶片和部位尚不清楚。本研究通过在自然长日照条件下,对光敏不育水稻农垦58S(NK58S)的不同叶片和部位套袋遮光作短日处理,探讨对育性转换的敏感部位。结果表明,在育性转换敏感期,NK58S最上两个叶片接受的光照长度决定其花粉育性,其中尤以心叶对育性的贡献最大,将倒二叶及叶鞘和心叶同时遮光可增加NK58S育性恢复的稳定性。对叶片的不同部位遮光有效应差异,对叶片的上半部分遮光不能使育性转换,反之对下半部分遮光能使育性转换。另外可观察到遮光短日处理育性恢复的植株,其抽穗期比育性未恢复及整株长日处理者提前约10d。表明水稻开花的光周期和雄性育性的光周期反应有一定的关联。

Photoperiod-sensitive genic male sterile rice（PSGMSR） has the characteristics that its pollen fertility is regulated by photoperiod;It is completely sterile under long-day conditions but fertile under short-day conditions.PSGMSR has now been widely used in two-line hybrid rice breeding.Despite extensive studies on various aspects of the PSGMSR,the leaves and the sites where photoperiod response occurs to induce fertility change is unknown.In this study,we investigated the sites of response by examining pollen fertility of plants with differential short-day treatments of the leaves as well as different parts of the leaves,by bagging various parts of the original mutant Nongken 58S.The results showed that the uppermost two leaves are responsible for photoperiod response for sterility induction.The uppermost unexpanded leaf is the most critical for photoperiod response,and the second leaf and its sheath played important roles in enhancing the fertility response.Short-day treatments of different parts of the leaves also have different effects on fertility.Covering the upper parts of the two uppermost leaves did not affect fertility,while bagging the lower parts of the leaves resulted in fertility alteration.In addition,the treatments that increased fertility also accelerated the heading by approximately ten days,indicating that photoperiod responses of the pollen fertility and flowering may be governed by related processes.