芭蕉科花蜜腺形态比较: 兼论其与传粉者的关系

对狭义芭蕉科3个属的代表性种芭蕉(Musa basjoo)、象腿蕉(Ensete glaucum)和地涌金莲(Musella lasiocarpa)的花蜜腺形态进行了比较研究。结果表明它们的蜜腺属于隔膜蜜腺。雌花的蜜腺着生于子房的上部, 胚珠的上方; 雄花蜜腺占据了整个败育子房的位置。蜜腺结构由许多腔道组成, 这些腔道在横切面上呈现出复杂的发散式迷宫状结构。这3种植物花蜜腺的栅栏状表皮细胞、维管束和蜜腺开口方式相似, 而从纵切面和横切面上观察其结构存在一些差异。PAS反应显示象腿蕉泌蜜组织中淀粉粒含量高于其他两个种; 芭蕉和象腿蕉的蜜腺腔里有许多纤维状物质存在。3种植物的传粉综合征多样化, 花序和花的特征(如花序下垂或直立、苞片的颜色、泌蜜量和泌蜜时间等)和传粉样式之间有密切关系。它们的蜜腺结构和传粉者行为之间没有明显的相关性, 但是胶质或水质的花蜜对传粉者的取食方式有一定影响。

Morphological comparison of floral nectaries in Musaceae, with reference to its pollinators

The floral nectaries of three species of Musaceae s. s. representing the genera Musa, Ensete and Musella were comparatively investigated. Our observations revealed that nectaries of these three genera belonged to the interlocular septal type. In female flowers, nectaries were limited to the upper part of the ovaries above the locules, while in male flowers (with aborted ovaries) nectaries entirely occupied the aborted ovaries. A transection of nectary ducts suggested a complex and highly proliferated labyrinthine structure. The three species shared a few common features in the palisade-like epithelial cells, vascular supplies, and nectary openings. However, they showed some differences in longitudinal section and transectinal outline. The nectaries of Ensete glaucum had the highest starch content, and those of Musa basjoo and E. glaucum had fibrillar material presented in nectar ducts. Pollination syndromes among the three species showed high diversity, while inflorescence and flower characters (such as pendant or erect inflorescences, bract color, nectar volume and production over time, etc.) and pollination patterns were highly correlated. There were no strong correlations between nectary structures and pollinator behavior, although gelatinous or watery nectar was associated with the foraging preference of pollinators.