Flower Heliotropism of Alpine Plants and Its Adaptive Significance

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.