Abstract:

Temporal dioecy, a flowering mechanism of synchronous alternation of pistillate and staminate phases in hermaphroditic (bisexual) flowers or monoecious individuals, decreases the probability of self-fertilization in self-compatible (SC) species. The authors report the prevalence of flexistyly in native species of Alpinia Roxb. in Xishuangbanna, Southwest China, resulted in dimorphism with two temporal dioecious floral phenotypes that facilitates out-crossing. Populations of ginger plants Alpinia have two specific phenotypes that differ in flowering behavior: (1)“cataflexistyle”individuals with the stigma held erect beyond dehiscent anther when anthesis begins in the morning and becoming decurved under the anther at noon; (2)“hyperflexistyle” individuals with the receptive stigma decurved under the indehiscent anther first and moving into a reflexed superior position above the anther as it begins to shed pollen at midday. The stigmatic movements in the two floral phenotypes, which occur in a ratio of 1∶1 in natural populations, are synchronous and pollination is effected only between floral forms. Field experiments indicate that species of Alpinia are self-compatible and insect dependent fertilization plants.

山姜属植物花柱卷曲性传粉机制的研究
李庆军 许再富*  夏永梅 张玲 邓晓保 高江云
（中国科学院西双版纳热带植物园，云南勐腊666303）

摘要：暂时性雌雄异株是一种在两性花或雌雄同株植物个体上表现出的雄蕊和雌蕊成熟时间不同而形成的暂时性雄性阶段和雌性阶段不重叠的现象。这种现象减少了自交亲和的雌雄同株和两性花种类发生自交的可能性。作者系统研究了花柱卷曲性传粉机制在西双版纳姜科山姜属 (Alpinia Roxb .)植物中的普遍性 ,这一机制使得植物通过完全的暂时性雌雄异株达到了异交的目的。这类植物的种群中具有两种独特的表现型 ,其差异表现在开花行为的不同 :柱头下垂型个体在刚开花时其柱头向上反卷 ,位于已开裂的花药上方 ,到中午开始向下运动 ,下午则位于花药下方 ;柱头上举型个体的柱头在开花初期向花冠内卷曲 ,位于未开裂的花药和唇瓣之间 ,中午开始向上运动 ,当柱头上举到花药上方后 ,花药开裂 ,花粉开始散发。两种个体的开花行为是同步的 ,通过两种柱头反向运动这一独特的开花行为 ,植物成功地避免了同种表型内的自交。野外实验表明 ,山姜属植物是自交亲和类群 ,不同的授粉方式 (不同时间的自花和异花授粉 )具有相同的结实率 ,但套袋的花序几乎不结实。两种表型在自然种群中的比例为 1∶1

关键词： 山姜属；花柱卷曲性；柱头上举型；柱头下垂型；传粉生物学

Key words: Alpinia, flexistyly, hyperflexistyly, cataflexistyly, pollination biology