高山植物花的向日运动及其适应意义
Flower Heliotropism of Alpine Plants and Its Adaptive Significance
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摘要: 花的向日性是一种花部运动的行为,通过花梗的弯曲或转动使花冠或花序能够追踪太阳,从而有效改善花内或花序温度,有利于吸引传粉者和促进其生殖器官的发育,以提高繁殖成功率。花的向日性是高山植物热量适应行为的典型代表之一。通过对花的向日性研究,有助于进一步了解花部运动对植物雌雄功能的影响。而到目前为止,对它的运动机制和进化过程的认识仍存在着许多疑问,如植物是如何平衡向日增温和蒸腾失水,花的哪些部位对追踪太阳起主导作用等。主要概述了植物(尤其是高山植物)的花向日性生物学特性、运动行为及其生态适应意义,并结合作者已开展的工作,对进一步深入研究花的向日运动提出一些有益的建议。Abstract: Flower heliotropism is a type of plant behavior whereby the corolla or inflorescence tracks the sun by bending or rotating its peduncle.By improving the temperature within flowers or inflorescences,this behavior may accelerate the growth of sexual organs and/or increase pollinator attraction,such that reproductive success is enhanced.Flower heliotropism of alpine plant thus represents an adaptive behavior in response to solar heat.Studies on flower heliotropism may provide important information on the differential benefits of floral movement in correlation with male and female function.Several puzzles remain regarding movement mechanisms and the evolution of the flower heliotropism,such as how plants balance the heat gained via heliotropism with water lossed via transpiration,and which floral parts drive flower heliotropism.In this paper,we summarize recent advances in the study of alpine flower heliotropism,especially with respect to biological characters,movement behavior and adaptive significance.In conjunction with our field observations,we propose some suggestions for future studies of flower heliotropism.