三种欺骗性兰花的传粉生态学 
任宗昕 
学位类型博士
导师李德铢 ; 王红 
2010-11
学位授予单位中国科学院研究生院
学位专业植物学
摘要兰科植物是被子植物的大科之一,但生境丧失和过度采集使得兰科植物成为最濒危的植物类群之一。当今,在全球气候变化和生物多样性的迅速丧失的大背景下,兰科植物的保育显得极其重要和迫切。传粉生态学的研究可以为兰花的保育提供理论依据。有研究猜测杓兰属三稜组(Cypripedium Sect. Trigonopedium)为蝇类传粉,但一直未见详尽的报道和对其传粉机制的解释。对虾脊兰属(Calanthe)的传粉生态学的研究仅见极少种类的昆虫描述。本论文以云南巧家药山国家级自然保护区的毛瓣杓兰(Cypripedium fargesii)、药山虾脊兰(Calanthe yaoshanensis)和三棱虾脊兰(C. tricainata)三种濒危植物为研究对象,通过研究其繁育系统,进一步揭示了传粉昆虫与兰花的互作关系和传粉吸引机制,并在此基础上提出了的保育建议。主要结论如下:1.三种兰花都不为传粉昆虫提供任何形式的报酬,通过欺骗实现传粉;都是自交亲和的,在自然条件下没有自交机制。异交种子具有活性胚的比例显著高于自交种子,表明都存在自交衰退。2.毛瓣杓兰的传粉昆虫为专性的扁足蝇(Agathomyia sp.),扁足蝇作为有花植物的传粉昆虫为本研究首次报道。毛瓣杓兰拟态受真菌感染的叶片,吸引扁足蝇访问,在有花植物的传粉中是一种全新的拟态方式。其主要证据:(1)在扁足蝇成虫口器和足上发现大量有枝孢菌(Cladosporium sp.)的菌丝和分生孢子,表明成虫以真菌孢子为食。枝孢菌能感染植物叶片和果实形成深色霉斑块;(2)毛瓣杓兰叶片正面具有黑色或红黑色的斑块,与受该类真菌感染的其他植物的叶片非常相似;(3)花气味中3-methyl-1-butanol为典型的霉菌的气味成分,该化合物与2-ethyl-1-hexanol和1-hexanol普遍存在于枝孢菌的挥发物成分中。因此,毛瓣杓兰利用扁足蝇特殊的食性,其带斑块的叶片和花气味拟态被枝孢菌感染的叶片,从而达到诱骗扁足蝇传粉的目的。3.新种药山虾脊兰的主要传粉昆虫为蜂蝇(Eristalis tenax)。药帽存留的时间大于昆虫访花时间,从而起到阻止自交和克隆群体内近交的作用。传粉吸引方式为泛化的食源性欺骗,黄色花、假蜜导和花气味吸引昆虫拜访。 4.三棱虾脊兰的主要传粉昆虫是密林熊蜂(Bombus patagiatus)。生境破坏严重,自然条件下结实率极低。带刺的黄背栎和峨眉小檗在一定程度上,成为了三棱虾脊兰的护理植物。5.本研究对三种兰花的保护提出建议。毛瓣杓兰以原生地保护为主,两种虾脊兰可以进行原生地保护和迁地保护。
资助项目Orchidaceae is one of the largest families in angiosperm, but sadly they are among the most threatened of plants due to over collection and habitat loss. The conservation of orchids is more important and imminent under current climatic change scenarios. Orchids always have complex ecological interactions with pollinators, therefore it is critical to know their pollination strategies when apply conservation policy and techniques. The slipper orchids of Cypripedium Section Trigonopedia were thought to be pollinated by flies, yet no detailed experimental evidence was provided until now. The genus Calanthe comprises 150 species, only three of them have been observed their pollinators. In this dissertation, we investigated the pollination ecology of three orchids, Cypripedium fargesii Franch., Calanthe yaoshanensis Z. X. Ren et H. Wang and C. tricarinata Lindl. at the Yaoshan National Natural Reserve, Qiaojia, northeastern Yunnan, China. This study examined habitat, phenology, floral traits, pollinators, floral scent and reproductive success for each orchid. We dissected their pollination systems and deciphered attraction mechanisms involved. Finally we provided a conservation strategy for each orchid. 1. Breeding system, Cypripedium fargesii, Calanthe yaoshanensis and C. tricarinata are all self-compatible. However, there are no autogamy mechanisms under natural conditions; pollinators are needed for successful reproduction. The proportion of fully developed and viable embryos of cross-pollinated seeds is significantly higher than self-pollinated seeds. Post-zygotic fatality was the main cause for aborted embryo development of self-pollinated ovaries. 2. Pollination ecology of Cypripdium fargesii, Cypripedium fargesii is almost exclusively pollinated by mycophilous flat-footed flies in the genus Agathomyia (Platypezidae, Diptera). Our study is the first to report the flat-footed fly to be the pollinator of flowering plants. We suggest a novel deceptive pollination system that specifically targets flat-footed flies in C. fargesii. The orchid accomplishes its deception through morphology and offactory mimicry of ascomycete fungi infected leaves:(1) We found mycelia and conidia of Cladosporium sp. (Davidiellaceae) on the surface of mouthparts and tarsi of examined flies, this indicates that adult Agathomyia fly is feeding on fungal spores. Cladosporium always infects leaves and fruits of wild and cultivate plants and causes black mold spots on the surface of leaves and fruits. (2) The upper surface of orchid leaves are scattered with black or blackish maroon spots, also with a cluster of multicells chain-like trichome at the center of spots. These spots are similar to fungi infected mold spots on the surface of leaves. (3) The flower produce more than 50 scent molecules associated with a wide variety of flowers, leaves and fruits. 3-methyl-1-butanol, 2-ethyl-1-hexanol and 1-Hexanol are also detected from Cladosporium, and 3-methyl-1-butanol is a typical microbial organic compound. The leaves of orchids and scent molecules mimic of ascomycete fungi infected leaves to attract flat-footed flies to find fungal spores for food. The orchid utilizes the special food habit and feeding behaviours of flat-footed flies. 3. Pollination ecology of Calanthe yaoshanensis. Calanthe yaoshanensis Z. X. Ren et H. Wang is a new species published by author. The main pollinator is drone fly (Eristalis tenax). C. yaoshanensis provides no reward to insect visitors, its pollination strategy is generalized food deception. The pollinators of C. yaoshanensis are attracted to bright yellow-colored perianths and alcohol-related sweet scent of the flowers. 4. Pollination ecology of Calanthe tricarinata, The insect visitation to C. tricarinata is very scarce, and Bombus patagiatus, the primary pollinator, carries pollinaria on its head. The pollination strategy is generalized food deception. The bumble bees are probably attracted by the yellow-colored sepals and petals, and brick-red lip of the orchid flowers. The fruit set is very low, 1.20%, 2.96% and 2.74% for 2008 to 2010 years, significant difference among three years. Low fruit set is due to severe pollinator limitation in over-grazing habitat. 5. Conservation strategies, Cypripedium fargesii is suggested to be conserved in situ, and both in situ and ex situ are recommended for conservation of two Calanthe species.
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/16060
专题昆明植物所硕博研究生毕业学位论文
推荐引用方式
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任宗昕 . 三种欺骗性兰花的传粉生态学 [D]. 中国科学院研究生院,2010.
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