植物的花特征变化通常会影响植物的交配系统，进而可能会改变近交衰退和种群的遗传多样性，但在缺乏传粉者的高山环境中，植物的花特征与交配系统和种群遗传多样性的关系仍不明确。兼具自交和异交能力的两年生植物椭圆叶花锚的花大小随纬度升高表现出显著降低的趋势，表明随纬度升高椭圆叶花锚可能存在由异交向自交进化的趋势，为花特征、交配系统和种群遗传多样性的相互关系研究提供了一个理想的材料。本项目拟通过在纬度梯度上采集不同种群的叶片和种子，检测不同种群的自交率和遗传多样性，并通过野外实验和同质园实验揭示花特征进化的选择压力以及近交衰退在不同生活史阶段的表达。本项目的研究结果将在种群水平揭示植物花特征对交配系统、近交衰退和遗传多样性的影响，并能拓宽我们对高山短命植物繁殖策略和混合交配系统维持机制的理解。

Plant mating system could be affected by the variations of floral traits, and inbreeding depression and population genetic diversity might change correspondingly. However, it still remains unclear on the relatinships among floral traits, mating system and the population genetic diversity in alpine environments, where pollinator service is generally considered to be scarce. Halenia elliptica, a biennial with wide distribution in China, could produce seeds via both selfing and outcrossing, and a negative relationship was found between flower size and latitude in this plant, indicating the transition from outcrossing to selfing, which might be a good material to examine the relationships among floral traits, selfing rate, inbreeding depression and genetic diversity. In this proposal, based on wide collections of the leaves and seeds in different populations of H. elliptica along the latitudinal gradients, we will examine the selfing rate and the population genetic diversity. Moreover, we will examine the changes in floral character, expression of inbreeding depression in different stage of life history based on field experiments and common gardens. Our results in this proposal will discover the effects floral traits on mating system, inbreeding depression and genetic diversity on population level, and enhance our understanding on the reproductive stragety of short-lived alpine plants and maintenance of mixed mating system.