多倍体茶树的细胞学研究(二)

对1株自然三倍体茶树和1株人工诱变四倍体茶树的细胞学研究,结果表明,三倍体茶树在减数分裂的终变期,花粉母细胞中的染色体联会成9种价体,其中三价体的出现频率最高,平均为6.33次,因而初步推断为同源三倍体。由于部分落后染色体的丢失,后期Ⅱ仅有4.9%的极区具有正常的15条染色体,花粉萌发率仅为10.1%,这是该三倍体茶树高度不育的原因。四倍体茶树是同源四倍体,在终变期,花粉母细胞中的染色体联会成14种价体,其中四价体出现的频率最高,平均5.34次;二价体出现的频率次之,平均4.73次。染色体可联会成多价体环

Cytological Study on Polyploid Tea

Cytological study on a natural triploid tea plant and a artificial inducedtetraploid tea plant was carried out.Results showed that in the diakinesisof meiosis,nine forms of valents were observed in the PMC of the triploid,and the average frequency of trivalents in each PMC examined reached6.33,the highest among all mean frequencies of the valents,indicatingthat the triploid was the autotriploid.Due to the loss of some lagging chro-mosomes,the 15 normal chromosomes existed in only 4.9% of the polarzones in AⅡ and only 10% of the pollens could germinate,resulting in thehighly steritily of the triploid.The tetraploid proved to be the antogenic.In the diakinesis of meiosis,14 forms of valents were observed in the PMC,and some multivalents had the shape of closed ring or open chain.Amongall mean frequencies of the valents in each PMC,that of the quadrivalent,reaching 5.34 occupied the first place and that of the bivalent,reaching4.73,came the second.In the AⅡ of meiosis,and 34.2% of the 30 normalchromosomes existed in 34.2% of the polar zones and 36.7% of the pollenscould genminate,resulting in an evidently different fertility from that ofthe triploid.