紫薇多倍体的诱导、鉴定及内多倍性研究

以紫薇子叶期幼苗为试验材料,采用不同秋水仙素浓度和时间组合处理其生长点,成功获得四倍体(2n=4x=96)和六倍体(2n=6x=144)。诱变株与二倍体对照植株形态差异明显,植株矮小粗壮,叶片变皱、粗糙,增厚,气孔密度减小,气孔保卫细胞(一对,下同)长、宽分别增大65.79%和45.01%,保卫细胞内叶绿体数量增加80.25%,且颗粒增大。四倍体花粉粒直径增大59.07%,花瓣长宽略有增加,但花序长和花朵数反而减少。人工诱导四倍体和普通二倍体茎尖都有内多倍化现象,并且前者内多倍化水平低于后者。

Induction, Ploidy Determination and Endopolyploidy of Polyploid in Lagerstroemia indicaL

Tetraploid （2n=4x= 96） and hexaploid （2n= 6x= 144） plants were successfully induced from seedling of Lagerstroernia indica L. by processing shoot apical meristem with colchicine. The results indicated that the variants, which were characterized by stunted but stout plant, wrinkled and thicker leaves, less stoma frequency, larger（length rised by 65.79 % and width, 45.01%） guard cells （a pair, the same as below）, more larger（rised by 80.25%） chloroplasts in each pair of guard cells, were significantly different from the diploid plants in morphology. Tetraploid plant got markedly larger （rised by 59. 07%） pollen grains, slightly larger petals, longer inflorescence but less flowers than diploid plants. Endopolyploidy was observed in both induced tetraploid plant and diploid plant, and endopolyploidy degree of the former was lower than that of the latter.