药物诱导玉米孤雌生殖植株的倍性变异

实验结果表明，孤雌生殖植株根尖体细胞以二倍体细胞最多，占６８．９％，其次为非整倍体细胞，占２８．７％，其他异倍体和单倍体细胞极少（２．４％）。Ｐａ１植株可分为二倍体和混倍体两类，以二倍体细胞占绝对多数的混倍体植株最多，为８３．５％，这些植株生长发育和结实均正常。在花粉母细胞中正常二倍体频率比根尖体细胞明显提高，提高频率为３５．３一５９．６％，不同材料之间趋势一致。讨论了体细胞染色体变异的来源及其能否延续到生殖细胞。

Ploidy Variation of Chemically-Induced Parthenogenic Maize Plants

The chromosomal ploidy variation in parthenogenic maize plants induced by chemical treatment was studied.Aneuploid,haploid and polyploid cells were observed in addition to diploid cells.Most of the cells(68.9%) were diploid with 20 chromosomes,28.7% wereaneuploids,a few heteroploid and haploid cells(2.4%)were found.Two types of chemically-induced parthenogenic plants Pa_1 were found.They were diploid and mixoploid plants.Of these mixoploid plants,cells were found to be predominantly diploid with percentage almost 83.5%.Normal growth and development of them were observed.Meiotic analysis demonstracted that in parthenogenic plants frequency of normal univalent at the diakinesis stage in PMCs was more than in root-tip cells the pecentage of which was increased ranging from 35.3-59.6%.The possible origin of variation in root-tip somatic cells and the possible inheritance of the variation in generative cells were also discussed.