Аннотация:Microspore segmentation in anthers of the barley line C4-13 cultured on a modified N6 medium was followed for 10 days to examine the routes to multicellular structure formation and origin of nonhaploid chromosome numbers. The first division of the uninucleate microspores gave rise to two similar nuclei or a large vegetative and a small generative cell. The two similar nuclei divided independently and both contributed to the formation of multicellular structures. Independent division of the vegetative and generative cell, and division of the vegetative cell alone resulted in two other pathways to multicellular structure formation. Nuclear fusion and endomitosis occurred in some pathways and appeared to be involved in ploidy variation. In addition, a very low frequency of fusion between the nuclei of two microspores was observed. This event may account for the occasional presence of heterozygosity in microspore-derived plants.Key words: barley (Hordeum vulgare), anther culture, androgenesis, ploidy level, nuclear fusion, endomitosis, gene expression.
