Adaptive significance of mass-flowering in Hedychium coccineum (Zingiberaceae).
Adaptive significance of mass-flowering in Hedychium coccineum (Zingiberaceae).
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DOI：
10.3724/sp.j.1003.2012.10034
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发表时间：
2012-05-01
期刊：
影响因子：
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通讯作者：
Yang, Shuxia
中科院分区：
文献类型：
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作者：
Gao, Jiangyun;Sheng, Chunlin;Yang, Shuxia
同时开出多朵花的两性植物可能会吸引更多的传粉者，创造更多的交配机会。然而，这也可能导致地理配偶制，这可能会对性别分配、花特征和雌雄异株的进化产生重大影响。本文通过人工授粉和人工操作实验、传粉者观察、种群密度和自然座果率调查等方法，对球花蛇舌草的传粉生物学进行了研究，以探讨球花蛇舌草大开花的适应性意义。总体而言，球果的花序由57.33[正负]1.68(n=30)个果穗组成，每个果穗有3.8[正负]0.15(n=30)朵花。花序内的每朵花依次开放，花序内的每朵花之间相同的圆花在连续的同步循环中开放。这提供了一个穗状物，使大量的花朵在整个花期同时盛开。球果百合在花序水平上表现出较大的花朵展示。此外，球果海棠是自交亲和的，不发生自发自花授粉。自然种群中球果蛾的果实产量受到传粉者的严重限制。同时，球孢子虫在水果生产中的资源也是有限的。三种蝴蝶Papilio Memnon、Dercas lycorias和Appias Indra aristoxemus是球果小蜂的有效传粉者。3种蝴蝶对3种不同展花大小的花序的访花频率有明显差异，随着花序展花大小的增加，访花频率增加。球果百合的花粉粒和胚珠在百合属不同轮次的花中差异较大。第一轮至第四轮胚珠产量显著下降，而第一轮至第三轮花粉粒显著增加。胚珠的减少和果实生产的资源限制表明，球果海棠大量开花不是为了增加果实产量。第一轮至第三轮的花粉粒数增加，有利于花粉输出，提高男性适合度。
Hermaphroditic plants that simultaneously display multiple flowers may attract more pollinators and create more chances for mating. However, this may also lead to geitonogamy, which may have major impacts on evolution of sex allocation, floral characteristics, and dioecy. To explore adaptive significance of mass-flowering in Hedychium coccineum, we conducted studies on pollination biology of H. coccineum, via hand-pollination and manipulated experiments, pollinator observation, and investigations on population density and natural fruit sets. Overall, inflorescences of H. coccineum were composed of terminal spikes containing 57.33 [plus or minus] 1.68 (n = 30) cincinnus, and each cincinnus possessed 3.8 [plus or minus] 0.15 (n = 30) flowers. Flowers in each cincinnus opened in turn, and the same round flowers among each cincinnus within inflorescences opened in successive synchronous cycles. This provided a spike that kept a mass of flowers blooming simultaneously throughout the flowering period. H. coccineum displayed a large floral display at the inflorescence level. Additionally, H. coccineum was self-compatible, and spontaneous self-pollination did not occur. Fruit production of H. coccineum in natural populations was severely pollinator-limited. Meanwhile, H. coccineum was also resource-limited in fruit production. Three butterflies, Papilio memnon, Dercas lycorias, and Appias indra aristoxemus were effective pollinators of H. coccineum. Visiting frequencies of these butterfly species to three inflorescences with different floral display size were obviously different and visitation frequencies increased as the inflorescence increased in floral display size. Pollen grains and ovules of H. coccineum varied significantly among flowers of different rounds in the cincinnus. Ovule production decreased significantly from the first to the fourth round, but pollen grains increased significantly from the first round to the third round. The decrease in ovules and resource limitation in fruit production indicated that mass-flowering in H. coccineum was not for increasing fruit production. The increase in pollen grains from the first round to the third round benefits pollen export and increases male fitness.