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

摘要

The microsporogenesis and male gametophyte development of wild-type (WS2) and (epn) mutant Arabidopsis thalianum has been investigated by electron microscopy. The extra pollen nuclei (epn) mutant, whose characteristics include more than one nucleus inthe 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 thetetranucleate 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 mutantmicrosporogenesis. It is suggested that the epn mutant specific defects in pollen mother cell development during premeiosis or meiosis II.