Cytological studies on meiosis and male gametophyte development in cucumber

Southern and Northern Chinese cucumbers were used to study meiosis and male gametophyte development using improved staining and chromosome preparing methods.The results obtained included:① the meiosis in PMCs of cucumber was simultaneous cytokinesis.Chiasmata could be seen clearly in diplotene and the chromosomes could be identified as rod or ring bivalents.The multi-nucleoli and the nucleoli fusion were observed at both telophase Ⅰand telophase Ⅱ;② The microspores in tetrad stage showed the arrangement of decussate type instead of isobilateral type;③ Two nucleuses were centrally placed in male gametophyte development.Only one layer of pollen wall was developed during the centrally placed nucleus stage,and two layers of pollen wall were in side-placed nucleus stage;④ Mature pollen grains were bicellular.