玉叶金花种内性状置换的初步研究

通过对茜草科玉叶金花属植物玉叶金花传粉生物学及种内形态分化和分布特点的初步研究,发现该种的两个变种玉叶金花和白花玉叶金花在形态和生境适应上都有一定的规律。研究表明,楠藤与开黄花的玉叶金花原变种的传粉者主要是鳞翅目昆虫,而玉叶金花的白花变种的有效传粉者是膜翅目昆虫。认为变种白花玉叶金花居群的出现与同属植物楠藤的同域分布及避免相互竞争传粉者有关。白花玉叶金花变种的出现属于性状置换现象。     

异型雄蕊植物花内雄蕊的分化

Flowers that have heteromorphic stamens （heterantherous flowers） have intrigued many researchers ever since the phenomenon was discovered in the 19th century. The morphological differentiation in androecia has been suggested as a reflection of ＂labor division＂ in pollination in which one type of stamens attracts pollinators and satisfies their demand for pollen as food and the other satisfies the plant＇s need for safe gamete dispersal. The extent and patterns of stamen differentiation differ notably among taxa with heterantherous flowers. Seven species with heteromorphic stamens in three genera were sampled from Leguminosae and Melastomataceae, and the morphological difference of androecia, pollen content, pollen histochemistry and viability, pollen micro- morphology, as well as the main pollinators were examined and compared. Pollen number differs significantly between stamen sets of the same flower in most species investigated, and a correlation of pollen number and anther size was substantiated. Higher pollen viabilities were found in the long （pollinating） stamens of Senna alata （L.） Roxb. and S. bicapsularis （L.） Roxb. Dimorphic pollen exine ornamentation is reported here for the first time in Fordiophytonfaberi Stapf. The height of stigma and anther tips of the long stamens in natural conditions was proved to be highly correlated, supporting the hypothesis that they contact similar areas of the pollinator＇s body.     

异型雄蕊的研究进展

就异型雄蕊的概念、在被子植物中的分布、在传粉过程中的作用及其发育进行了概述,并对未来的研究方向作一展望.异型雄蕊指一朵花内的雄蕊在形态、大小、颜色等方面有显著的区别,并存在不同程度分工的现象.异型雄蕊在野牡丹科、茄科、干屈菜科、豆科、雨久花科等多个科中都有分布,但其分化与程度常随类群而异.虽然人们对于这一现象的认识由来已久,但研究尚不深入.对于异型雄蕊的研究可以加深人们对植物与其传粉者之间关系的理解,并为传粉生物学与植物繁育系统研究提供新的视角和启示.     

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。