大白菜2n配子发生的细胞学机制研究

Cytological Mechanism of 2n Gamete Occurrence and It's Application of Chinese Cabbage

研究了大白菜(BP058株系等)2n配子发生的细胞学机制。结果表明,由于中期II纺锤体定位方向变异,导致二极体和三极体形成,最终形成2n雄配子。其中三极体为2n雄配子形成的主要途径,比率高达86·5%。2n雌配子遗传传递率65·18%,远高于2n雄配子的传递率(23·29%)。二、四倍体杂交2n卵(2x=20)×n花粉(2x=20),其杂交胚乳和杂种胚能正常发育;而二倍体n配子与四倍体n配子杂交,虽能受精形成三倍体杂种合子,但授粉后15d胚乳完全解体,致使胚乳败育不能形成种子。

The cytological mechanism of 2n gamete occurrence of Chinese cabbage variety BP058 was studied. The results indicated that the orientation variance of the metaphase II spindles resulted in the formation of ambipolar bodies and tripolar bodies, and eventually caused the production of male 2n gametes. It was also demonstrated that tripolar body was the main pathway for 2n gamete formation with the ratio of 86. 5%. The genetic transfer rate of female 2n gametes was 65. 18% , much higher than that of male 2n gametes （23. 29% ）. For diploid and tetraploid cross, 2n ovum （2x=20）×n pollen （2x=20）, the hybrid endosperm and embryo developed normally. While for diploid n gamete and tetraploid n gamete cross, seeds could not be formed, although triploid hybrid zygote could be formed through fecundation, and the endosperm completely broke down 15d after pollination.