鹤顶兰花粉管在子房中的生长途径

Growth Paths of Pollen Tubes in Ovary of Phaius tankervilliae （Aiton） Bl. （Orchidaceae）

摘要:

运用扫描电镜对鹤顶兰（Phaius tankervdliae（Aiton）B1．）花粉管在子房内的生长途径进行了观察。结果表明：花粉管在子房中的生长途径可以分为3个阶段：（1）沿子房壁轴向生长阶段，从授粉开始至大孢子母细胞四分体时期，花粉管经过合蕊柱到达子房，经由胎座基部沿子房壁轴向生长；（2）沿子房径向生长阶段，二核胚囊之后，花粉管在胚珠之间穿梭，以径向生长为主；（3）朝珠孔定向生长阶段，胚囊成熟时，花粉管朝珠孔定向生长进入胚囊。实验结果说明花粉管的定向生长受胚珠的分子信号调控。

Abstract:

Pollen tube growth in the ovary of Phaius tankervilliae （Aiton） BI. （Orchidaceae） as observed under scanning electron microscope could be divided into three stages. In first stage, from the beginning ofpoUination to megaspore tetrad, pollen tubes grow axially, passing through gynostemium to the ovary and from proximal placenta along ovary wall develop upward. In second stage, after 2-nucleate embryo sac development, most pollen tubes grow radially around ovules. In third stage, at maturing of the embryo sac, pollen tubes grow directionally toward micropyle into embryo sac. It is suggested that directional growth of pollen tubes are controlled by molecular signal in ovule.