Patterns of flower morphology and sexual systems in the subnival belt of the Hengduan Mountains, SW China

Abstract

The adaptations of alpine plants that enable them to survive in extreme environments are hotly debated. Floral traits are likely important since they are usually considered as evolutionary adaptations to pollinators, and thus to play a key role in the reproductive success of plants. In the subnival belt of the Hengduan Mountains (a globally important biodiversity hotspot with extreme environmental conditions in southwest China) plants show diverse floral morphologies. However, information on the flower diversity of this unique alpine ecosystem is scarce, especially at the regional scale. Therefore, using published information, herbarium collections and field observations, we have studied the sexual system and floral morphology of plants in the subnival belt of the Hengduan Mountains. Of the 823 species recorded in the region, 88.5 % are hermaphroditic (a particularly high proportion compared to floras of other regions). The flower morphology patterns indicate that showy flowers (attracting pollinators) and generalized floral traits (suited to a wide range of pollinators) are common in our study region. Some floral traits were clearly associated with each other among specialized flowers as well as among generalized ones. Our results identify key reproductive features of plants in the subnival belt of the Hengduan Mountains, and show how these plants might optimize their probability of pollination and thus maintain reproductive success. The study provides a foundation for further research on floral adaptation and plant-pollinator relationships in the study region.