| Orchidaceae is one of the major families in angiosperm. There are approximately6subfamilies and725genera worldwide with around25000to30000species. China has about194genera and1388species of orchid which is not only with important scientific value, but also with extremely high appreciation value as well as important medical value and health care value. Orchid is very sensitive to the changes of ecosystem. With the development of social economy, the immoderate field acquisition, land clearance and land occupation by people have led to the habitat destruction or gradual disappearance. In addition, due to the impact of extreme climate caused by global warming, a variety of orchid is in danger, which is in urgent need of taking effective protection measures. As the natural population has been threatened seriously, orchid is generally considered as the hot issue and "flag" group of plant conservation study in the world.There are various abundant types of orchids in Guangxi Yachang Orchid National Nature Reserve with the characteristics of concentrated distribution and large-scale population, which is honored as the "hot spot of orchid worldwide" as an ideal place for scientific researches with important protection value. The establishment of the Reserve is definitely of great significance to the preservation and protection of local orchids. However, as the only Reserve named after orchid and taking orchid as the protection object, whether there are large amounts of wild orchid that hasn’t been discovered, recorded and protected, what are the composition structures and characteristics of orchid resources as well as factors influencing the orchid resources in Yachang Orchid Reserve, and what are the factors affecting the pollination efficiency by the orchid and pollinators in the biological reproduction process, still require further study.For this purpose, from October2011to October2013, the author spent2years of time in the Reserve for special survey on the wild orchid resources by collecting the materials of wild orchid resources within the area comprehensively, sorting out the orchid resource system, evaluating on the orchid in danger, and assessing the interference to orchids by people’s economic activities there. Meanwhile, due to the protection needs, Vanda concolor Blume and Eulophia zollingeri (Rchb. F.) J. J. Sm. are taken as the study objects for the observation study on ecological study of pollination, the main study results of which are shown below:1. Through the special resource study, it has been found that there were49genera and135species of wild orchid distributed within Guangxi Yachang Orchid National Nature Reserve. One new species of orchid named Habenaria yachangensis (Z. B. Zhang&W. Guo) was discovered, two new recorded species in Orchidaceae were found in Guangxi Zhuang Autonomous Region, namely, Calanthe tsoongiana (T. Tang et FT Wang) and Malaxis monophyllos (L.) Sw., and15new recorded species was found in the Reserve.2. Wild orchid resources in Guangxi Yachang Orchid National Nature Reserve are with the characteristics of diversified composition, complete life forms and various distribution types. There are three types of wild orchid distributed within Yachang Reserve, including the terrestrial, saprophytism and epiphytes (semi-epiphytes and vine), basically covering all life forms. The floral elements of orchid within the Reserve are complex and diversified with certain differentiation of many class groups within the region. Moreover, the orchid resources in the Reserve are with distinct tropical elements.3. The population size in Guangxi Yachang Nature Reserve is huge with centralized and regular distribution. There is a large scale of orchid within the Reserve with the single intensive distribution area of individual species covering3hm2or more, which is really spectacular. In terms of the horizontal distribution, orchid within the Reserve is distributed aggregately or sporadically. The aggregate distribution can be divided into the aggregate distribution of single species and the aggregate distribution of multi-species mixture, the latter of which is usually composed of stable species. The distribution of orchid at the altitude range of800m to1200m within the Reserve is intensive with rich categories, while that at the altitude <800m and>1200m is relatively small, which is basically in the sporadical status.4.7species in Guangxi Yachang Orchid National Nature Reserve have been included in the IUCN red list, in which there are3in vulneraabale(VU) level,3in endangered(EN) level, and1in critically endangered(CR) level. In addition to the newly released species, almost all orchids in the Reserve have entered to the "Red List of Chinese Species", among which there are24species in endangered(EN) level,50in near threatened (NT) level,44in vulneraabale(VU) level,8in critically endangered(CR) level, only3in least concern state and6without evaluation. The main courses for the destruction of orchid resources in the Reserve is the acquisition, land occupation and wasteland opening up, and illegal lumbering in the economic activities by local people.5. Pollination biology study of V. concolor. Pollination biology observation of V. concolor was investigated during2012and2013in the Guangxi Yachang Orchid National Nature Reserve. Our observations confirmed that the flowers were self-compatible but floral visitors were required. Both Xylocopa rufipes and Bombus kulingensis are the effective pollinators. X. rufipes is more effective than B. kulingensis. Foraging in the flowers mainly occurred in two periods:68%in10:00am-12:30pm and16%in13:30pm-14:30pm; Because the matchable functional morphology of labellum and the pollinators, the mechanical interaction between them provides dynamic support for effective pollination. Mahonia beaill, Stachyurus chinensis and V. concolor have same flowering season in observation location, the bright yellow color of M. beaill flowers is the same as spots color on V. concolor flowers. We considered the plant attracted pollinators into flowers for foraging by floral fragrance and yellow spots in flowers, and it was food-deceptive pollination mechanism.6. Pollination biology study of E. zollingeri. The floral biology and visitation of this plant were studied in Guangxi Yachang Orchid National Nature Reserve. E. zollingeri flowers are self-compatible but pollinators are required to achieve effective pollination; Nomia viridicinctula Cockerell is the only effective pollinator; Foraging in the flowers mainly occurs in three periods:8.6%in9:00-11:30AM,80.2%in11:30AM-14:00PM,11.2%in14:00-15:30PM; The flowers volatilize sweet floral fragrance under strong sunshine in the midday. We considered E. zollingeri attracts pollinators into flowers for foraging by the dizzy floral fragrance and bright yellow color in labellum, then the matchable sizes of flowers and the pollinators in functional morphology provides dynamic support for effective pollination. The pollinators receive no reward in the whole pollination procedure, it is food-deceptive pollination mechanism. |
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