摘要
本文对短柄五加（Ｅｌｅｕｔｈｅｒｏｃｏｃｃｕｓｂｒａｃｈｙｐｕｓ）的花期物候、开花式样、访花昆虫种类、访花行为及访花频率进行了观察，对花粉活力、柱头可授性、花粉胚珠比以及传粉效果和繁育系统做了检测。初步结果表明，短柄五加以根茎进行无性繁殖，１个居群为１个无性系。虽自交亲和，但昆虫的访花活动可显著提高座果率。昆虫传粉主要在无性系内异花间进行，属于广义的自花传粉。传粉者为多种不同的昆虫，包括马蜂和胡蜂在内的蜂类、蝇类和甲虫。其花期物候、花粉活力、柱头可授期和蜜汁分泌期等特征使其能够适应环境，从而获得较高的座果率。平均座果率为６５％，饱满种子率为４５．５％。自然条件下未发现实生苗，广义的自花传粉导致的种子质量低下可能是其原因，也是限制短柄五加分布范围的重要因素。
The authors not only observed flowering phenology, flowering pattern, species of visiting insects, visitation rate of pollinators and their foraging behavior, but also studied pollen viability, stigma receptivity, pollen ovule ratio, effect of insect pollination and breeding system. The results indicated that Eleutherococcus brachypus was in the progress of vegetative propagation and a population was a clone. A given flower kept open for about two days, but successive bloom of the flowers in a population lengthened its florescence for about 20 days. The pollen ovule ratio (P/O) was about 2500～3200. On the first day when Eleutherococcus brachypus was in bloom, the pollen grains shed. The viability of polen was over 90% and it lasted for over five days. The stigma has a receptivity of 10 days or so. Nectar secretion started on the first day and continued for about 10 days. Although it was physiologically self compatible, pollinator visitation could highly enhance fruit set. The invectors chiefly visited between 1200 and 1400 hours. Insects pollinated mainly among different flowers of the same clone, which, in a broad sense, belonged to self pollination. Pollinators were diverse small insects such as smallbees, wasps, flies and beetles. Artificial pollination experiments showed that under natural condition, the number of pollen on the stigma was inadequate. Eleutherococcus brachypus adapted to the habitat by such characteristics as its flowering season, high pollen viability, long time stigma receptivity and nectar secretion duration, thus its higher fruit set produced. The average fruit set ratio of Eleutherococcus brachypus was 65% while plump seed ratio was 45.5%. No seedling was found in the field. It seems that the poor quality of seeds caused by inbreeding depression accounted for this. The poor quality of seeds also limited the distribution of Eleutherococcus brachypus.
出处
《生物多样性》
CAS
CSCD
1997年第4期251-256,共6页
Biodiversity Science
基金
国家自然科学基金
关键词
短柄五加
开花
传粉
生物学
Eleutherococcus brachypus, flowering, pollination biology, visiting insect, breeding system
