Abstract:

Floral longevity, the length of time that a flower remains open and functional, is an important floral trait that influences plant reproductive success. Recently, there has been a large increase in research on floral longevity. Many advances have enriched our understanding of evolution and ecology of floral longevity. These studies focused on the effects of both pollination and non-pollination factors on variation of duration of flower anthesis, interactions between floral longevity and floral display, and relationships between floral longevity and reproductive assurance. However, no review has been available on these developments. We briefly summarize the development of theoretical studies on floral longevity and review the progress of empirical studies. The life history evolutionary theoretical mode suggested floral longevity was determined by costs of maintaining flowers and the fitness accrual rate, which was supported by many empirical studies. Experimental studies demonstrated that flower senescence is advanced by deposition of pollen grains on the stigma but pollen removal does not significantly affect floral duration. Some of these plants have a minimum longevity during which the flower never abscises. Environmental factors, such as temperature and water availability or humidity, can change costs of maintaining flowers and then change floral longevity. Because of the costbenefit of floral display, plants often adjust floral longevity to alter display size. Floral longevity also can adjust according to resource allocation. Long floral duration can provide reproductive assurance, but may suffer some fitness costs. Although progress has been made, many questions remain and we propose new ideas. For theoretical studies, male and female conflict provides a new perspective to understand the evolution of floral longevity. For empirical studies, we suggestthat evolutionary biologists should pay more attention to male fitness and analyze cost-benefit of floral longevity at the inflorescence level.

Key words: floral longevity, evolution, pollination, floral display, reproductive assurance