黄瓜花粉母细胞减数分裂及其雄配子体发育的细胞学研究

Cytological studies on meiosis and male gametophyte development in cucumber

以南方型和北方型两个生态型黄瓜为材料,用改良的染色和制片方法,较为系统的研究了黄瓜花粉母细胞(PMC)减数分裂及其雄配子体的发育过程。结果表明:1黄瓜减数分裂属于同时型胞质分裂,双线期染色体具有明显的交叉节并呈现出较易识别的棒状或环状形态,在末期 和末期 有多核仁和核仁融合现象;2在四分体时期的小孢子成十字交叉形(decussatetype),而非四边形(isobilateraltype);3雄配子体发育过程中观察到两核居中期的特殊现象,在核居中期小孢子只有一层壁,而在核靠边期小孢子出现了两层壁;4黄瓜的成熟花粉粒属于两核花粉粒。

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.