刺槐花粉萌发和花粉管伸长生长过程中柱头与花柱内钙离子的分布特征

Distribution of Ca^(2+) in the stigma and style of Robinia pseudoacacia during pollen germination and pollen tube elongation

以去雄后人工授粉的刺槐花为试验材料,并以去雄后不授粉的花为对照,利用焦锑酸钙沉淀法分析刺槐柱头和花柱内钙离子分布对花粉萌发和花粉管生长的影响。结果发现:花粉在萌发前,其萌发孔聚集了大量的钙沉淀。授粉作用会很快促使柱头表面泡状分泌物和胞外基质钙含量增加。随着大量花粉萌发完成,柱头泡状分泌物内的钙含量开始下降,但是柱头胞外基质的钙含量下降不明显,这表明柱头泡状分泌物的钙离子对花粉萌发可能有促进作用。刺槐的花柱含有一个中空花柱道,中空花柱道周围有一层通道细胞,不论授粉与否,通道细胞液泡和细胞壁上都有大量钙离子,这些钙离子对花粉管的生长可能有诱导作用。刺槐花柱内的钙离子梯度现象不明显。本研究结果有利于揭示刺槐乃至其他豆科植物柱头和花柱内钙离子分布对花粉萌发和花粉管生长的影响。

We used antimonate precipitation in combination with transmission electron microscope（ TEM） in order to investigate the distribution of Ca2 ＋in stigma and style of black locust（ Robinia pseudoacacia）and its effect on pollen germination and pollen tube growth. Experimental materials were emasculated flowers of black locust with artificial pollination and non-pollination as control. Our findings were asfollows. Before germination,a lot of Ca2 ＋was observed on and near the germinal pore. Pollination could increase the amount of Ca2 ＋in exudate vesicles and extracellular matrix on stigma. With the finishing of most pollen germination,the amount of Ca2 ＋in exudate vesicles started to decline; however,no obvious decrease occurred in extracellular matrix,indicating that the amount of Ca2 ＋in vesicles might promote pollen germination. A hollow stylar canal surrounded by a layer of canal cells was inside the style of black locust. Whether pollinated or not,lots of Ca2 ＋accumulated in the vacuoles and on cell walls of canal cells. Those Ca2 ＋may promote the pollen tube growth in vivo. Gradient distribution of Ca2 ＋in the style of black locust could not be observed. The results of this study are beneficial to revealing the distribution of Ca2 ＋in the stigma and style of black locust as well as other leguminous plants on pollen germination and tube elongation.