植物生态学报 ›› 2011, Vol. 35 ›› Issue (11): 1202-1208.DOI: 10.3724/SP.J.1258.2011.01202

• 研究论文 • 上一篇    

芳香石豆兰的繁殖生态学

陈玲玲1,2, 高江云1,*()   

  1. 1中国科学院西双版纳热带植物园, 云南勐腊 666303
    2中国科学院研究生院, 北京 100049
  • 接受日期:2011-06-07 发布日期:2011-11-07
  • 通讯作者: 高江云
  • 作者简介:*(E-mail:gjy@xtbg.org.cn)

Reproductive ecology of Bulbophyllum ambrosia (Orchidaceae)

CHEN Ling-Ling1,2, GAO Jiang-Yun1,*()   

  1. 1Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
    2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Accepted:2011-06-07 Published:2011-11-07
  • Contact: GAO Jiang-Yun

摘要:

芳香石豆兰(Bulbophyllum ambrosia)是分布于我国南方石灰岩山热带季节性雨林中的一种常见附生兰科植物, 附着生长于岩石或树干上, 野外监测发现其自然不结实。对芳香石豆兰繁殖生态学的研究表明, 不同于石豆兰属其他具有蝇类传粉综合征的种类, 其花具有香味和花蜜, 中华蜜蜂(Apis cerana cerana)是芳香石豆兰唯一的有效传粉者, 具有较高的访问频率, 自然种群中有较高的花粉块移出率和柱头花粉块沉降率, 在中华蜜蜂的传粉过程中, 芳香石豆兰铰链结构的唇瓣起着重要作用。人工授粉试验表明, 芳香石豆兰自交授粉不结实, 异交授粉结实率达90%以上, 芳香石豆兰为自交不亲和的繁育系统。芳香石豆兰具有较强的克隆生长能力, 同一个体花期内有大量的花同时开放, 其传粉者中华蜜蜂平均单次访花(4.29 ± 0.40)朵( n= 66), 造成了严重的同株异花传粉。芳香石豆兰附生于石灰岩山顶岩石或树干上, 种群密度较低, 使得不同个体之间花粉交流困难, 自交不亲和的特性导致了芳香石豆兰自然不结实。本研究结果为开展芳香石豆兰的有效保护提供了依据。

关键词: 不结实, 芳香石豆兰, 同株异花授粉, 兰科植物保护, 自交不亲和

Abstract:

Aims Bulbophyllum ambrosia is an epiphytic orchid growing on rocks and trees in limestone seasonal rainforests and is commonly distributed in southern China. We found no fruit set of B. ambrosia during long-term monitoring of species diversity, reproductive phenology and pollinators of local orchid species in Green Stone Forest Park. Our objective was to determine barriers to fruit set in B. ambrosia.
Methods Flowering phenology and natural fruit-set were monitored once a week for three years. Floral morphology was studied during flowering time. We also investigated the rate of pollinia removal and deposition over two flowering seasons. To determine the self-compatibility system, different hand-pollination treatments were conducted over three years at the study site. We also observed floral visitors for 150 h over two years.
Important findings Unlike other myophilous species in the genus, B. ambrosia is fragrant and presents nectar as reward. Observations of floral visitors showed that honeybee (Apis cerana cerana) was the only efficient pollinator and regularly visited flowers with high frequency. In natural populations, the rates of pollinia removal and deposition were high, but there was no fruit set. The hinged labellum plays an important role in the process of honeybee pollination of B. ambrosia. No fruit was found in the selfing pollination treatment, and fruit set of crossing pollination treatments was >90% over two years, suggesting that B. ambrosia is self-incompatible. To our knowledge, this is the first report of a self-incompatible species in Bulbophyllum. Individuals of B. ambrosia have a mass of flowers opening simultaneously during anthesis because of its strong ability in cloning. Honeybees visited 4.29 ± 0.40 flowers ( n = 66) in average per visitation, which may lead to geitonogamy. Self-incompatibility causes no fruit set as the result of geitonogamy. These results provide useful implications for future conservation of B. ambrosia.

Key words: absence of fruit set, Bulbophyllum ambrosia, geitonogamy, orchid conservation, self-incompatibility