Cytological Studies on the Meiosis and Male Gametophyte Development of Dioscorea parviflora

The meiosis and male gametophyte development of Dioscorea parviflora were studied using squash preparation. The results showed that there were four types of chromosome configuration at the metaphase Ⅱ, such as parallel-type, triangle-type, vertical-type (one plate) and vertical-type (two plate). The microspores in tetrad stage showed three arrangements, such as isobilateral tetrad, decussate tetrad, and tetrahedral tetrad. The male gametophyte development of D. parviflorata could be divided into 5 stages, including unicleate central-located stage, unicleate side-located stage, late-unicleate stage, pre-bicleate stage, and bicleate stage. Cytokinesis of microspore mother cells during meiosis was simultaneous type, and pollen grains were 2-cell, it suggested that the Dioscoreaceae was rather primitive in Angiosperm. The diversity of chromosome configurations at the metaphase Ⅱ had no relationship with the formation of 2n gametes.