关键词: 雌性适合度与花粉输出, 花性状进化, 绶草(Spiranthes sinensis), 时间变化, 背景环境影响表 型选择

Abstract:

Identifying the potential role of vegetation context (defined as the density, species identity/diversity and height of co-occurring plants) in modifying selection on floral traits is a critical step for clarifying and predicting the floral evolutionary trajectory in complex co-flowering species competition environments. It is also helpful to understand the variation in pollinator-mediated selection.

We experimentally reduced vegetation height around individual plants of Spiranthes sinensis (a bumblebee-pollinated perennial orchid herb) and estimated how vegetation context modified selection on four floral traits (flowering start, plant height, corolla size and number of flowers) through female function and pollen removal over two continuous years. We randomly selected independent plants in each year.

We demonstrated that vegetation context modified selection for earlier flowering start and shorter plant height of S. sinensis. The strength of selection differed between years. In addition, selection was stronger through female function than through pollen removal. Our findings indicate the potential role of vegetation context in shaping the differentiation and diversification of flowers in angiosperms.

Key words: female fitness and pollen removal, floral evolution, Spiranthes sinensis, temporal variation, vegetation context modification selection