长春蒲公英雄性不育株形态学观察与败育细胞学研究

Morphological and Cytological Study on Male Sterile Dandelion( Taraxacum junpeianum Kitam. )

在长春蒲公英(Taraxacum junpeianum Kitam.)株群中发现雄性不育现象,为研究其败育机理及特点,探寻其不育基因,采用形态观察法、石蜡切片技术和染色体压片法,对长春蒲公英野生型及其雄性不育株的花药发育过程和花粉母细胞减数分裂过程进行了观察。结果表明:(1)长春蒲公英雄性不育株花药中部发红、干瘪、无花粉散出。与野生型比较,雄性不育株雄蕊更短,子房更窄,种子形态更加狭长;(2)长春蒲公英雄性不育株败育时期为四分体到单核小孢子前期,败育方式为小孢子自身异常发育,绒毡层异常分解,互相粘连败育;(3)长春蒲公英雄性不育株花粉母细胞减数分裂二分体时期出现落后微核,随后产生极少四分体,并且四分体产生大量染色体桥,小孢子营养物质流失,彻底败育。因此,长春蒲公英雄性不育株败育彻底、稳定,并且有种的特点。小孢子自身异常发育和绒毡层异常分解是导致败育的主要原因。

Male sterile mutant was observed in Taraxacum junpeianum Kitam. To study the property and genes,we investigated anther development and pollen mother cell meiosis of male sterile mutant and wild-type of Taraxacum junpeianum Kitam. through morphology,paraffin section and chromosome technique. The results showed that the middle part of anther of male sterile mutant was red and withered without pollens. Compared with wild-type,male sterile mutant had shorter stamens,narrower ovaries,longer and narrower seeds. Abortion stage arose during tetrad to early mononuclear microspore,induced unusual decomposition of tapetum,and mutual adhesion of microspores.Lagged micronucleus was observed during dyad phase of microsporocyte meiosis in male sterile mutant,few tetrads of abounding chromosome bridges were emerged,loss of nutrients happened,leading to abortion of microspore eventually. The male sterility in the dandelion mutant was stable and thorough. Unusual decomposition of tapetum may result in male sterile of dandelion.