Caldesia parnassifolia (Bassi ex Linn.) Parl. in China has declined in number in r ecent years and is increasingly faced with the risk of extirpation arising from anthropogenic changes a...Caldesia parnassifolia (Bassi ex Linn.) Parl. in China has declined in number in r ecent years and is increasingly faced with the risk of extirpation arising from anthropogenic changes associated with rapid urbanization and expansion of both agriculture and infrastructure. To aid in provision of the data needed for effective conservation of the species, studies on the habitat, pollination ecology, and breeding system of C. parnassifolia were carried out on natural populations occurring in Southeastern China. Flowering in the study populations extended for more than eighty days beginning in early summer. Floral anthesis occurred in the morning hours and proceeded rapidly, lasting about 45 min. Flowers lasted ca. 8 h. Caldesia parnassifolia is self\|compatible; however autogamy resulted in lower seed set than geitonogamy and xenogamy as well as free pollination. The data on pollen/ ovule (P∶O) ratio is consistent with a partially selfing and outcrossing mating system. Interpopulational crosses yielded similar seed set to within\|population crosses. Agamospermy did not occur in the study populations. Propagation is achieved through seeds as well as through turions which commonly occur in the inflorescences. Flies (Insecta; Diptera) were the most frequent visitors to the flowers of C. parnassifolia; however bees (Insecta; Hymenoptera) composed a larger proportion of effective pollinators. The Syrphidae species Sphaerophoria indiana (Bigot) presents evidence of oligolectic foraging behavior. Recommendations are made on the immediate steps necessary for conservation of Caldesia species in China.展开更多
Rhynchanthus beesianus W. W. Smith （Zlnglberaceae） Is an eplphytlc tropical ginger with a very conspicuous floral display, but almost no fruit set under field conditions. The reproductive ecology encompassing phenol...Rhynchanthus beesianus W. W. Smith （Zlnglberaceae） Is an eplphytlc tropical ginger with a very conspicuous floral display, but almost no fruit set under field conditions. The reproductive ecology encompassing phenology, floral biology, and pollination and breeding systems was Investigated In an evergreen broadleaved forest In Yunnan Province, Southwest China. The flowers possess a typical bird pollination syndrome, but no effective pollinators were observed during 138 h of observation. Female Black-breasted Sunbird （Aethopyga saturata） and bumblebees visited R. beesianus regularly, but they all played roles as nectar robbers. No fruit was found In the bagging treatment, and fruit set following manual self-pollination （（57.55 ± 4.08）%） was comparable with cross-pollination （（64.32 ± 4.42）%）, suggesting that R. beeslanus is self-compatible but spontaneous self-pollination In this species does not occur. Seed set of open-pollination （（26.42 ± 3.11）%） was significantly lower than manual self-pollination （（73.41± 4.16）%） and cross-pollination （（75.56 ± 4.52）%）, confirming that R. beeslanus was dependent on animals for fertilization and suffered a serious pollinator-limitation.展开更多
文摘Caldesia parnassifolia (Bassi ex Linn.) Parl. in China has declined in number in r ecent years and is increasingly faced with the risk of extirpation arising from anthropogenic changes associated with rapid urbanization and expansion of both agriculture and infrastructure. To aid in provision of the data needed for effective conservation of the species, studies on the habitat, pollination ecology, and breeding system of C. parnassifolia were carried out on natural populations occurring in Southeastern China. Flowering in the study populations extended for more than eighty days beginning in early summer. Floral anthesis occurred in the morning hours and proceeded rapidly, lasting about 45 min. Flowers lasted ca. 8 h. Caldesia parnassifolia is self\|compatible; however autogamy resulted in lower seed set than geitonogamy and xenogamy as well as free pollination. The data on pollen/ ovule (P∶O) ratio is consistent with a partially selfing and outcrossing mating system. Interpopulational crosses yielded similar seed set to within\|population crosses. Agamospermy did not occur in the study populations. Propagation is achieved through seeds as well as through turions which commonly occur in the inflorescences. Flies (Insecta; Diptera) were the most frequent visitors to the flowers of C. parnassifolia; however bees (Insecta; Hymenoptera) composed a larger proportion of effective pollinators. The Syrphidae species Sphaerophoria indiana (Bigot) presents evidence of oligolectic foraging behavior. Recommendations are made on the immediate steps necessary for conservation of Caldesia species in China.
基金Supported by the National Natural Science Foundation of China （30400055）.
文摘Rhynchanthus beesianus W. W. Smith （Zlnglberaceae） Is an eplphytlc tropical ginger with a very conspicuous floral display, but almost no fruit set under field conditions. The reproductive ecology encompassing phenology, floral biology, and pollination and breeding systems was Investigated In an evergreen broadleaved forest In Yunnan Province, Southwest China. The flowers possess a typical bird pollination syndrome, but no effective pollinators were observed during 138 h of observation. Female Black-breasted Sunbird （Aethopyga saturata） and bumblebees visited R. beesianus regularly, but they all played roles as nectar robbers. No fruit was found In the bagging treatment, and fruit set following manual self-pollination （（57.55 ± 4.08）%） was comparable with cross-pollination （（64.32 ± 4.42）%）, suggesting that R. beeslanus is self-compatible but spontaneous self-pollination In this species does not occur. Seed set of open-pollination （（26.42 ± 3.11）%） was significantly lower than manual self-pollination （（73.41± 4.16）%） and cross-pollination （（75.56 ± 4.52）%）, confirming that R. beeslanus was dependent on animals for fertilization and suffered a serious pollinator-limitation.
