拟南芥野生型及突变体小孢子发生和发育的比较研究

通过电镜对拟南芥野生型及ｅｐｎ型突变体小孢子发生和发育进一步研究（此突变体的特征是花粉从游离核时期就具有多核、多沟并有分枝的花粉管），值得注意的是突变体在发育至四核花粉母细胞时期，在整个母细胞原生质膜外开始形成小孢子的外壁（与野生型晚期四分体内单倍体小孢子原生质体外形成的外壁相同），此外，在突变体小孢子发生的整个过程中也未见到正常四分体的出现。因此，设想具有两个营养核、两个生殖核的突变体的大花粉直接由非正常的四核花粉母细胞形成，突变体发生缺失的时期在前减数分裂期或减数分裂Ⅱ

Comparative Studies on Microsporogenesis and Male Gametophyte Development of Wild-type and Mutant Arabidopsis thalianum

The microsporogenesis and male gametophyte development of wild-type (WS 2) and (epn) mutant Arabidopsis thalianum has been investigated by electron microscopy. The extra pollen nuclei (epn) mutant, whose characteristics include more than one nucleus in the pollen from the free microspore stage onward, extra colpi in abnormal orientation, and branched pollen tubes. A particularly interesting feature of the epn phenotype is that exine of microspore is formed around the outside of the plasmalemme of the tetranucleate microspore mother cells, so the mutant pollen with two vegetative nuclei and two generative nuclei seems able to come from the abnormal tetranucleate microspore pollen mother cells directly, no normal tetrad has been found during the mutant microsporogenesis. It is suggested that the epn mutant specific defects in pollen mother cell development during premeiosis or meiosis II.