Variation of microsporogenesis in sexual, apomictic and recombinant plants of Poa pratensis L.

Abstract

Apomixis is a rather widespread phenomenon in plants. It is defined as the asexual formation of a seed from the maternal tissues of the ovule, avoiding the processes of meiosis and fertilization. Some species are facultative apomicts and form seeds by means of sexual and apomictic pathways to different extents. This is the case of Poa pratensis, the Kentucky bluegrass, which reproduces by aposporous pseudogamous facultative apomixis. This grass is one of the most studied apomictic systems, however some aspects, such as the male meiotic behavior, have not been so far investigated. In this study the process of microsporogenesis in genotypes of P. pratensis with a different mode of reproduction was investigated. The analysis revealed an almost regular meiosis in the sexual plants whereas apomictic genotypes exhibited different levels of meiotic irregularities, mainly due to cell fusion and irregular segregation in I and II division. Our data did not reveal evident connections between the extent and types of abnormalities and the components of apomixis, apomeiosis and parthenogenesis. The meiotic behavior of the examined plants was discussed in the light of their origin.