摘要
本文报道陆地棉单倍体的鉴定及其细胞遗传学研究的结果。1987年作者在美国引入的端体材料中出现一株矮生,叶、花均比正常陆地棉小、并表现雌、雄不育的陆地棉单株。观察花粉母细胞(PMC)减数分裂中期Ⅰ的染色体仅有26条,是1株陆地棉的单倍体。分析了505个 PMC 减数分裂中期Ⅰ的染色体构型.其中66.86%都是26个单价体,25.35%是24个单价体另加1个二价体;有1个细胞还出现了三价体。平均每个 PMC 的交叉结数为0.4812,染色体构型平均25.1584Ⅰ+0.4178Ⅱ+0.0020Ⅲ。后期Ⅰ,绝大部分的 PMC 染色体随机地分向两极,两极的染色体数非常不一致。此外还可观察到染色体分向三极、四极的PMC。单倍体 PMC 第二次减数分裂的各个时期常可观察到微核。四分孢子期,单倍体可以观察到一分孢子到十分孢子等各种不同类型,其中以六分孢子为多。多分孢子的形成可能是由于单倍体染色体分离不均衡产生多极而造成的.单倍体的花粉粒大小不均匀,平均为52.4微米,仅为正常的104.7微米的一半。讨论了单倍体 PMC 在 MI 低配对频率的可能原因。
The identification and cytogenetics of a haploid plant in Upland cotton (Gossypium hirsutum L.)were studied.One dwarf plant with leaves and flowers smaller than normal Up- land cotton was found in the telosomic material obtained from the Unietd States:This abnor- mal plant with zigzag stem was male and female sterile.Twenty-six (26) chromosomes were observed through the analysis of the pollen Mother Ceils (PMCs) in Metaphase I,therelly on- ly half of the 52 chromosomes of the mormal cotton plant.This plant could be considered as a haploid of the 505 PMCs,66.86% were 26 univalent and 25.35% were 24 univalent plus 1 bivalent The average association per cell was found to be 25.1584 Ⅰ+0.4178Ⅲ+0.0020Ⅲ with 0.4812 chlasma.In Anaphase 1,the chromosome was randomly distributed to two poles (some ever to three or four)for most PMCs.Micronucler were often observed m the second meiotic division.Polyads from monoad to decads appeared m the Tetrad phase,wheras hesads was prommant.They might be produced through the unequal distribuuon of chromo-somes in Anaphase I Pollen grams ot haplord were unequal in size and diameter with only 52 4um which is only half ot that of the normal plant(104 7um) The reason toy the low frequcncy of hromosome paoinng om MI on haplord cotton plant was discussed
出处
《棉花学报》
CSCD
北大核心
1989年第1期25-28,T001,共5页
Cotton Science
关键词
陆地棉
单倍体
细胞遗传学
Gossvpium mrsutum
Haploid
■yiogeneucs
