Pollination ecology of Gentiana siphonantha (Gentianaceae) and a further comparison with its sympatric congener species

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	Pollination ecology of Gentiana siphonantha (Gentianaceae) and a further comparison with its sympatric congener species
	Hou, Qin-Zheng ; Meng, Li-Hua ; Yang, Hui-Ling
	2008-07-01
发表期刊	JOURNAL OF SYSTEMATICS AND EVOLUTION
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 3 1, 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 their distinct difference in flower morphology. This finding is inconsistent with the previous hypothesis that both flower color and corolla tube depth have coevolved with different pollinators during speciation and formation of reproductive isolation. Both visit frequencies of the individual flower and geitonogamous visits within the individual plant are higher in G. siphonantha than in G. straminea. This difference may result from their different inflorescence designs that actively act upon behaviors of pollinator. Although these two species differed in flowering phenology, their flowering stages overlapped for a few days, suggesting incomplete pollination isolation between them.
文献类型	期刊论文
条目标识符	http://210.75.249.4/handle/363003/48497
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	Hou, Qin-Zheng,Meng, Li-Hua,Yang, Hui-Ling. Pollination ecology of Gentiana siphonantha (Gentianaceae) and a further comparison with its sympatric congener species[J]. JOURNAL OF SYSTEMATICS AND EVOLUTION,2008.
APA	Hou, Qin-Zheng,Meng, Li-Hua,&Yang, Hui-Ling.(2008).Pollination ecology of Gentiana siphonantha (Gentianaceae) and a further comparison with its sympatric congener species.JOURNAL OF SYSTEMATICS AND EVOLUTION.
MLA	Hou, Qin-Zheng,et al."Pollination ecology of Gentiana siphonantha (Gentianaceae) and a further comparison with its sympatric congener species".JOURNAL OF SYSTEMATICS AND EVOLUTION (2008).