菜薹二倍体与四倍体间杂交的杂种不育性研究

目的]研究菜薹二、四倍体间杂交的授粉受精和胚胎发育过程，为十字花科植物杂交不育研究提供参考。方法]以“青露”菜薹为试验材料，对其二、四倍体间杂交的授粉受精过程及细胞胚胎学进行了观察。结果]4x×2x和2x×4x杂交，花粉在异己柱头上均能正常萌发，2种杂交组合均有较高的胚珠膨大率。在4x×2x的杂交组合中，胚胎可正常发育到心形胚，之后胚乳开始迅速退化消失，随之内珠被细胞出现大量坏死，胚胎发育营养来源断绝，最终形成小粒种子。2x×4x的胚胎败育方式与4x×2x基本相似，但发生时期较早，球形胚时期胚胎解体，最终没有小粒种子形成。结论]菜薹二、四倍体间杂交的授粉受精过程正常，胚胎发育过程出现异常是其败育的主要原因。

Study on Hybrid Seed Failure by 4x×2x and 2x×4x in False Pakchoi(Brassica parachinensis)

Objective] The research aimed to study the process of pollination,fertilization and embryo development of diploid and tetraploid false pakchoi(Brassica parachinensis) with cross-pollination,to provide references for hybrid seed failure of Cruciferae plant.Method] With Brassica parachinensis L.H.Bailey as experiment materials,the process of pollination,fertilization and embryo development of diploid and tetraploid false pakchoi with cross-pollination was observed by fluorescence microscopy and paraffin section.Result] The process of pollination,fertilization and the fertilized ovules was normal in 4x×2x and 2x×4x.The cause of embryo collapse in both 4x×2x and 2x×4x combinations due to the tapetum cells and the inner integument cells dying off following the endosperm degeneration abnormally.But the time of embryo collapse was earlier in the 2x×4x combination than in the 4x×2x combination,generally at glob-shaped embryo stage in the former and the late heart-shaped embryo stage in the later.Conclusion] The process of pollination and fertilization of diploid and tetraploid false pakchoi with cross-pollination was normal.The embryo collapse is the mostly cause of cross-pollination failure.