钙在被子植物受精过程中的作用

近年来，花粉管中的钙信号和生理功能的研究取得了明显的进展，同时在雌蕊系统中有关钙分布的研究也初步显示了其时、空特征与被子植物的受精作用密切相关。该文总结了花粉萌发和花粉管生长过程中外源钙和内源钙的作用机制，结合雌蕊组织中钙分布的特征，进一步探讨了钙在被子植物受精过程中的功能。

Calcium Function in Fertilization Process in Angiosperms

The fertilization process in angiosperms in a broad sense begins since pollen grains land a stigma. The process continues as the pollen germinates, and pollen tube grows through pistil and finally reaches embryo sac in where fertilization occurs. In the process calcium plays important roles in controlling pollen tube growth during its journey toward embryo sac and promoting the fusion of both sperm and egg cells. It has been established in vitro experiment that tip high intracellular calcium gradient is correlated with its growth and it is necessary for some extracellular calcium to keep the gradient. In trace of pollen tube in pistil, from stigma, transmitting tissue of style, micropyle of ovule to degenerated synergic of embryo sac, there is abundant calcium that quickly dissipates after pollen tube passed. It is the temporal and spatial characteristics of calcium in pollen tube and pistil that make pollen tube exactly reach embryo sac and insure fertilization. This review discusses recent advance in studies on calcium role in fertilization process of angiosperm, especially from calcium distribution in pistil to confirm its roles in fertilization of angiosperm.