Study on substances regulating pollen germination in Japanese chestnut

以日本栗（Castanea crenata Sieb.）等Zucc.）与胚珠的发育有关。虽然雄花已经开始开花，但柱头上的花粉萌发和花粉管生长是在花柱停止生长后才开始的。花柱发育初期的水浸提液对花粉萌发和花粉管生长有明显的抑制作用，但当花柱停止生长时，其抑制作用消失。提取液的HPLC分析表明，抑制物质可能是莽草酸，从保留时间估计。提取液中的糖含量在花柱生长初期、花粉萌发初期和花粉管在柱头上生长初期均较高。当花粉管开始在柱头上生长时，胚珠的发育处于早期阶段，此时子房中的每个胚珠都没有珠心形成。对不同分析条件下提取液的HPLC分析表明，柱头上花粉萌发前后和花粉管开始生长后，花柱产生的抑制和促进物质都可能存在。然而，这些物质的产生和胚珠的发育之间没有明显的关系。因此，花粉在柱头上的萌发和花粉管的生长受柱头和花柱自身产生的物质的调控。

The study was conducted to clarify the substances regulating pollen germination and pollen tube growth in the styles of Japanese chestnut (Castanea crenata Sieb. Et Zucc.) in concerned with development of ovules. Pollen germination and pollen tube growth on the stigma began after the style ceased to grow, although the anthesis of male flowers had already began. The solution extracted with water from the styles at early stage of the growth repressed remarkably pollen germination and pollen tube growth, although its repressive effect disappeared as the style ceased the growth. The HPLC analysis of the extracted solution showed that repressive substance might be shikimic acid, as estimated from retention time. Sugar content in the extracted solution was higher both at early stage of the style growth and at the beginning of pollen germination and pollen tube growth on the stigma. When pollen tubes began to grow on the stigma, the development of ovules was at early stage in which no nucellus was formed in each ovules in a ovary. The HPLC analysis of the extracted solution under different analytical condition showed the possibility of existence of both repressive and promotive substances which were produced by styles before and after pollen germination and pollen tube growth began on the stigma, respectively. However, no distinct relationship between the production of those substances and the development of ovules was indicated. Therefore, it was concluded that pollen germination and pollen tube growth on the stigma were regulated by the substances produced from stigma and style themselves.