大白菜DH系同源四倍体的获得及其细胞学研究

Obtaining and cytological observation of tetraploid Chinese cabbage

以大白菜DH系为材料进行了多倍体的诱导和细胞学研究。结果表明：用1g／L秋水仙素药液处理籽苗生长点24～72h均可有效地诱导细胞染色体加倍，其中48h的诱变效果最好，四倍体株率达71．43％；四倍体植株长势良好，叶片、花蕾、花、保卫细胞、花粉粒等器官和细胞都明显大于其二倍体植株；四倍体的减数分裂行为较二倍体的复杂，终变期每个同源组的4条染色体或联会成四价体（Ⅳ）或2个二价体（Ⅱ＋Ⅱ）或1个三价体和1个单价体（Ⅲ＋Ⅰ）；中期Ⅰ二价体、四价体和三价体排在赤道面上，单价体游离在赤道面周围；后期Ⅰ，同源染色体大多呈2／2分离，偶见落后染色体，分到两极的染色体数主要为20／20和19／21，各占54．17％和29．17％；四倍体植株的花粉量充足，花粉生活力达77．31％。

Polyploidy inducing and cytological observation of Chinese cabbage were conducted in this paper. The results were as follows： seedling apex of Chinese cabbage DH line treated with 0.1 ; colcbicines solution for 24-72 h can efficiently double the chromosomes, in which the treatment for 48 hours achieved the highest percentage of tetraploid plants; the tetraploid plants developed normally, their blades, flower buds, flowers, guard cells, pollen grains and other organs or cells were obviously larger than those of their diploid plants; the meiotic behaviors of tetraploid plants were much more complicated than their diploid plants, for example, the four homological chromosomes may form a quadrivalent （Ⅳ） or two bivalents（ Ⅱ＋Ⅱ ） or one trivalent and one univalent（ Ⅲ＋Ⅰ） at diakinese; the bivalents, trivalents and quadrivalents collected on the equator plate and the univalents dispersed over the equator plate at metaphase Ⅰ ; some chromosomes may lag behind the other chromosomes and the number of chromosomes in either pole of cell may be 18, 19, 20, 21 and 22 at anaphase Ⅰ ; the pollen amount of the tetraploid plants was abundant, and the pollen viability was approximately 77.31%.