叶下珠科花粉组织化学、花粉数和胚珠数及其与传粉者关系的研究

植物花粉中营养物质的储存形式以及单花的花粉数与胚珠数被认为与其传粉系统有一定的联系。本文研究了叶下珠科部分种类的花粉组织化学、花粉数和胚珠数,以及它们与传粉者之间的关系。结果显示:在叶下珠科内,植物花粉所含营养成分和传粉者之间存在相关性:蛾类传粉的类群主要属"淀粉型"花粉,蝇类和蜂类传粉的类群主要属"非淀粉型"花粉。蝇类传粉和蛾类传粉的植物花粉数没有一定规律。蝇类传粉的类群比蛾类传粉的类群胚珠数少,这可能是由于蝇类携带花粉能力及传粉精确性均较小,导致植物以减少胚珠数来适应的结果。对同一属内不同生活型植物的花粉数比较,发现乔木的单花花粉数高于灌木,灌木的单花花粉数明显高于草本。这可能是由于不同生活型的植株,其花朵大小不同,导致花粉数出现明显差别。另外,通过扫描电子显微镜对花粉形态的观察,发现蝇类传粉的类群和蛾类传粉的类群间的花粉表面纹饰存在显著差异。

Relationships between pollen histochemistry, pollen grain number, ovule number and pollinators in Phyllanthaceae

The nutritive reserves in angiosperm pollen grains and the pollen and ovule numbers of single flowers are considered to be correlated with the pollinating vectors. In this paper, we studied the relationships between pollen histochemistry, pollen grain number, ovule number and pollinators in Phyllanthaceae. Hymenoptera-and Diptera-pollinated species tend to have starchless, lipid-rich pollen while most Lepidopteran-pollinated species have starchy pollen grains. No correlation was found between pollinator-types and pollen number of single flowers. Flowers of fly-pollinated species have much fewer ovules than flowers of moth-pollinated species. It is suggested that the decrease in ovule number may be an adaptation to the pollinating flies, which have relatively poorer pollen-transferring ability and which transfer pollen less precisely in comparison with other pollinating insects such as moths or butterflies. Pollen grains in single flowers of shrub species were found to be almost ten times as many as that of herbs, while the tree species also have higher pollen grain numbers than congeneric shrub species. This may be due to the different flower size in plants with different life forms. Significant differences were found in the pollen ornamentation patterns under SEM between fly-pollinated and moth-pollinated species.