结球甘蓝同源多倍体的诱导及鉴定

Obtaining and cytological observation of polyploid cabbage

以结球甘蓝自交系‘0501’为材料进行了多倍体的诱导和鉴定研究。结果表明：用蘸0.1%秋水仙素药液的脱脂棉小球处理籽苗生长点24~72h均可有效地诱导细胞染色体加倍,其中24h的诱变效果最好,四倍体株率为77.78%;四倍体植株长势良好,花蕾、花冠、花粉粒、保卫细胞、叶片、等器官和细胞都明显比二倍体植株的大;叶绿体数随倍性提高（2x、4x、8x）而提高;气孔密度、叶片长宽比和花瓣长宽比随倍性增加而减小;四倍体植株的减数分裂行为较二倍体的复杂,终变期和中期Ⅰ可见四价体、三价体、二价体和单价体等联会形式;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18/18和17/19,各占68.57%和24.29%;四倍体植株的花粉量充足,花粉生活力达87.27%;四倍体植株的DNA相对含量是其二倍体的2倍,Vc、粗蛋白及含糖量较其二倍体均有所提高。

Polyploidy inducing and identification of cabbage were conducted in this study. The results showed that seedling apex of cabbage treated with 0.1 % colchicines solution for 24 -- 72 h efficiently doubled the chromosomes, in which the treatment for 24 hours achieved the highest percentage of tetraploid plants, 77.78% The tetraploid plants developed normally, and the blades, flowers, flower buds, guard cells, pollen grains were obviously larger than those of their diploid plants. The number of chloroplast per guard cell became larger with the chromosome doubling （2x, 4x and 8x）. The density of stoma, ratio of blade length to width, and ratio of petal length to width were obviously reduced with the chromosome doubling. The meiotic behaviors of the tetraploid plants were much more complicated than their diploid plants, for example, four chromosomes in each homologous unit may form a quadrivalent or two bivalents or a trivalent and a univalentat at diakinese, and the distributions of chromo-somes at anaphase I were mainly 18/18, approximately 68.57%. The pollen amount of tetra- ploid plants was abundant, and the pollen viability was about 87.27%. DNA content of the tetraploid was doubled than its diploid. Contents of Vc, crude protein and soluble sugar in the tetraploid leaf were higher than its diploid.