中文摘要：

在青藏高原东北部连续两年观察了晚秋开花植物管花秦艽Gentiana siphonantha的传粉生态学特征,并在此基础上进一步比较分析了与该物种同域分布且亲缘关系较近、但开花较早的麻花艽G.straminea之间的传粉生态学特征。管花秦艽的花发育过程表现出雌雄异熟和雌雄异位的特点,不存在花内的自花传粉,套袋隔离的花不结实也支持这一结论;株内自交的高结实率表明该物种是自交亲和的。盛花期每植株平均有15朵开放的花,雄性和雌性阶段的花比例为1.2：1;自然条件下产生种子必须依赖传粉媒介;苏氏熊蜂是最有效的传粉昆虫,且访花过程中对雄性和雌性阶段花不具明显的偏向性;株内连续访花的频率高达87.8%,从而导致同株异花传粉自交的广泛存在。与同域分布的麻花艽相比,管花秦艽的单花花期、雄性和雌性期持续时间缩短。但盛花期开花数量明显增加。令人感兴趣的是尽管两个近缘种的花形态特征存在显著差异,但都是由同一种熊蜂传粉。这一特点与过去认为花颜色和花管长度是物种分化过程中与不同传粉昆虫协同进化导致生殖隔离的假说不相符合。管花秦艽单花的访花频率和同株异花连续访花的比例都明显高于麻花艽。两个物种不同花序设计导致访花昆虫行为的改变可能是造成这一差异的主要原因。两个物种具有不同的开花时间,但仍然存在一定的花期重叠,表现出不完全的传粉生殖隔离状态。

英文摘要：

In this study, we studied pollination ecology of Gentiana siphonantha （Gentianaceae）, a late-autumn flowering alpine perennial in the northeastern Qinghai-Tibetan Plateau for two years for the first time. We also aimed to compare the pollination differentiation between this species and sympatrically distributed G. straminea that has a close phylogenetic origin but is flowering early. Flowers of G. siphonantha are characteristic of dichogamy and herkogamy and this floral development prevents occurrence of autonomous self-pollination. This implication was confirmed by the breeding experiments, since no seed was produced when flowers were isolated. However, this gentian proved to be highly self-compatible when geitonogamous selfing was artificially induced. Each individual plant of this species has an average of 14.6 flowers ranging from 4 to 31, at both staminate and pistillate stages with a ratio of 1.2： 1 in full anthesis. Both floral development and breeding experiments suggested that pollen vectors were indispensable for successful seed sets of this species. A great variety of insects were observed to visit this species, but the most common and only legitimate pollinator is Bumbus sushikini. A statistic observation suggested that this pollinator showed no preference to either staminate or pistillate flowers and visited them at random. We further calculated the frequency of their visits between and within individual plants. Among the pollinators＇ bouts, the proportions of geitonogamous visits within an individual plant occupy about 87.8%. Such a case implied that geitonogamous selfing prevails in this species in spite of floral dichogamy and herkogamy that were suggested to promote outcrossing. Compared with sympatric G. straminea, the total floral longevity and the male and female duration of this species are shorter. However, the number of flowers of each individual plant and branch increased when in full anthesis. It is interesting that both closely related species shared the same pollinator despite t