棉属两个种间杂种一代雌配子体发育的比较研究

Comparative study on the Female Gametophyte Development of Two Interspecific F 1 Hybrids of Gossypium

用常规石蜡切片法，对草棉×异常棉（Ａ１×Ｂ１）、草棉×长须棉（Ａ１×Ｂ３）两个杂种一代与各自双亲之一的异常棉和长须棉的雌配子体发育进行了比较研究。结果表明，两个杂种一代大孢子母细胞减数分裂的起始时间比亲本推迟１～２ｄ，减数分裂过程持续时间多２ｄ，雌性败育主要发生在四分孢子到大孢子期间，Ａ１×Ｂ１Ｆ１和Ａ１×Ｂ３Ｆ１败育胚囊分别占观察总数的６６．７％和７１．０％，且在单核至成熟胚囊期间也有较多的异常胚囊类型。败育的主要原因是产生胚囊的大孢子染色体组成不完整。两个杂种在开花前一天的花蕾中，正常成熟的胚囊分别占１５．４％和１０．４％。

The development of female gametophyte of F 1 hybrids between G.herbaceum (A 1)×G.anomalum (B 1) and G.herbaceum (A 1)×G.barbosanum (B 3) were studied by paraffin sectioning method. It was found that the meiosis of the two interspecific F 1 hybrids took place 1￣2 days later but the meiosis period took two more days than their male parents. The female abortion of A 1×B 1 and A 1×B 3 hybrids occured from the stage of thtrad to the stage of megaspore and the proportion of aborted embryo sac reached 66.7% and 71.0% among the investigated ovule, respectively. Moreover, there were many types of abnormal embryo sac from uninuclear to mature embryo sac stages. The female abortion might be caused by abnormal chromosome constitution of megaspores, which led to forming different kinds of abnormal female megatophytes. One day before flowering, the normal embryo sac of A 1×B 1 and A 1×B 3 were 15.4% and 10.4%, respectively, which showed that in case of G.anomalum and G.barbosanum were closer to G.herbaceum.