青藏高原高寒草甸植物花寿命与花吸引特征的关系及其对雌性繁殖成功的影响

花寿命指花保持开放且具有功能的时间长度, 是开花植物繁殖成功的一个重要功能性状。可塑性延长花寿命是植物在不利的传粉环境中保障繁殖的一种策略, 但延长花寿命也会增加繁殖成本。花寿命的可塑性变异不仅受传粉环境的影响, 而且还受资源分配权衡的影响。花寿命的理论模型指出, 植物的花寿命与花吸引特征之间存在资源分配权衡。为了研究在花粉限制环境中, 植物花寿命与花吸引特征之间的资源权衡及其对雌性适合度的相对重要性。该研究以青藏高原高寒草甸不同海拔(2 900和3 600 m)的11种开花植物为研究对象, 分析了不同植物群落中, 物种水平上: (1)花寿命与花吸引特征(花大小以及开花数目)之间的相关关系; (2)花寿命与花吸引特征对植物雌性适合度的相对贡献。结果表明, 无论是低海拔还是高海拔植物群落, 植物的花寿命与开花数目之间均存在权衡关系, 且长的花寿命增加了植物的雌性适合度。但在高海拔环境中, 植物的雌性适合度只与花寿命有关。这说明相对于低海拔植物, 花寿命对高海拔植物的雌性繁殖成功更为重要。

Relationships of flower longevity with attractiveness traits and their effects on female fitness of alpine meadow plants on the Qinghai-Xizang Plateau,China

Aims Flower longevity, the length of time that flowers remain open and functional, is an important floral trait that influences plant reproductive success. Prolonging floral longevity can provide reproductive assurance under unfavorable pollination environment, but may suffer some fitness costs. The theoretical models of flower longevity have suggested that there is a trade-off of resources allocation between the flower longevity and attractiveness traits. Flower longevity can adjust according to resource allocation. To understand the potential adaptive significance of flower longevity, it is necessary to disentangle the potential relationships between flower longevity and attractiveness traits (flower size and number) and their effects on female fitness of alpine meadow plants at the inter-species level on the Qinghai-Xizang Plateau. Methods In the alpine meadows of Qinghai-Xizang Plateau (2 900 m vs. 3 600 m), we assessed how the relationships between floral longevity and flower attractiveness traits of 11 species varied at the inter-species level under different pollination contexts. And we quantified the relative contribution of flower longevity and flower attractiveness traits to the female fitness of plants at the inter-species level at low and high habitats. Important findings Results show that there is a trade-off between flower longevity and flower number in both low and high altitude communities. And we found that both longer flower longevity and larger flower size increase the female fitness of plants in low-altitude communities, However, the female fitness of plants is only associated with flower longevity in high-altitude communities. Overall, our results suggest that flower longevity is more important for the female fitness in high-altitude plants than low-altitude plants.