腐生植物无叶美冠兰食源性欺骗传粉研究

Deceptive pollination of a saprophytic Orchid, Eulophia zollingeri

关键词:  绿彩带蜂  无叶美冠兰  腐生兰  花部特征  食源性欺骗机制

Key words:  Nomia viridicinctula  Eulophia zollingeri  saprophytic orchid  floral syndrome  food-deceptive pollination mechanism

摘要:

无叶美冠兰是一种典型的腐生兰科植物,为揭示该物种的自然传粉机制,拓展对兰科植物生殖特性的认识,在广西雅长兰科植物国家级自然保护区对其开展了传粉生态学观测研究。结果表明:无叶美冠兰花朵具备高度自交亲和能力,但不存在自动自花授粉机制,必须依赖外部传粉媒介把花粉送到柱头,实现有效传粉; 绿彩带蜂是无叶美冠兰唯一有效传粉昆虫; 传粉昆虫与花朵在与传粉功能相关的关键性状在形态上良好拟合; 绿彩带蜂的访花活动主要发生在3个阶段:8.6%发生在9:00～11:30,80.2%发生在11:30～14:00,11.2%发生在14:00～15:30; 花朵在中午强烈的阳光直射下挥发出香甜的气味。无叶美冠兰花朵主要通过挥发极具诱惑力的香甜气味和唇瓣上黄色的蜜导来诱导绿彩带蜂进入花朵中觅食,传粉昆虫与花朵在与传粉功能相关的关键性状在形态上良好拟合促成有效传粉,绿彩带蜂在整个传粉过程没有获得报酬,是食源性欺骗传粉机制。

Abstract:

Eulophia zollingeri is one typical saprophytic species in Orchidaceae. Pollination biology of saprophytic orchid has been poorly studied. In order to reveal the significant pollination mechanism of E. zollingeri,broaden our knowledge on reproductive biology of saprophytic orchid,the floral biology and visitation of this plant were studied in Yachang Orchid National Nature Reserve,the west of Guangxi Province,China. E. zollingeri flowers were self-compatible but pollinators were required to achieve effective pollination; Nomia viridicinctula Cockerell was the only effective pollinator; Foraging in the flowers mainly occurs in three periods:8.6% in 9:00-11:30 AM,80.2% in 11:30 AM-14:00 PM,11.2% in 14:00-15:30 PM; 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 received no reward in the whole pollination procedure,it was food-deceptive pollination mechanism.