Identification of pre-fertilization reproductive barriers and the underlying cytological mechanism in crosses among three petal-types of Jasminum sambac and their relevance to phylogenetic relationships.

摘要: Crosses among single-, double- and multi-petal jasmine cultivars (Jasminum sambac Aiton) are unable to easily generate hybrids. To identify the reproductive barriers restricting hybrid set, dynamic changes in pollen viability pistil receptivity were compared at different flowering stages. Pollen-pistil interactions six reciprocal crosses also investigated characterize pollen-stigma compatibility. Additionally, paraffin sections of pollinated embryo sacs prepared for subsequent analyses developmental status. Furthermore, cell ultrastructural characteristics observed reveal cytological mechanism regulating pollen-pistil interactions. We that stigma varied depending on petal phenotype stage lost during flowering. Different exhibited compatibilities according germination rates. Although some grains germinated normally maternal stigmas, tubes arrested pistils reach ovaries. remained unfertilized until degenerating. Therefore, affected by pre-fertilization barriers. Low fertility poor detrimental compatibility, indicating they two factors affecting set. Ultrastructural observation cells revealed death occurred Thus, early rapid senescence is likely responsible decreased inhibited tube growth. These findings may be relevant future hybridizations. They provide new insights development methods overcome useful clarifying phylogenetic relationships with differing phenotypes.