两种同域分布的马先蒿属植物花特征与报酬间的相关性及表型选择

Correlation and phenotypic selection between flower characteristics and rewards of two sympatric Pedicularis species

为了研究植物花特征与报酬的相关性及表型选择,以青藏高原东部高寒草地的半扭卷马先蒿和甘肃马先蒿为研究对象.结果表明,花特征与报酬间相关性显示,半扭卷马先蒿的花粉数与花数目间呈显著的正相关,与株高呈显著的负相关;甘肃马先蒿的花特征与花蜜量无显著相关性,但与糖类物质存在着相关性,即花蜜量与糖浓度间呈显著的负相关,与糖含量呈显著的正相关.通过雌性适合度估计花特征所受的表型选择结果显示,两种马先蒿的花序数均受到了定向选择,说明花序数越多的个体,其适合度越高,但两种植物的花报酬性状均未受到定向选择.半扭卷马先蒿的株高也受到定向选择作用,说明株高越高的植物个体能产生更多的种子.非线性选择分析结果表明,甘肃马先蒿的花序数与花大小、盔高受到相关选择作用,表明花序数多且花越小的植物个体,以及花序数多且盔高越高的植物具有更高的雌性适合度.平均单花花蜜量受到显著的分裂选择,说明花蜜量较低或较高会增加植物个体的雌性适合度.两种植物的花性状与花报酬均未受到显著的相关选择.

In order to study the correlation and phenotypic selection between flower characteristics and rewards, the Pedicularis semitorta in the alpine grassland of the eastern edge of the Tibetan Plateau and Pedicularis kansuensis in Gansu were taken as research objects. The results showed that there was a significant positive correlation between the pollen number and flower number, and a negative correlation between the pollen number and plant height of P. semitorta. There was no significant correlation between flower characteristics and nectar amount of P. kansuensis, but there was a significant correlation between nectar amount and sugar concentration, namely, both a significant negative and a significant positive correlation between nectar amount and sugar concentration. Estimating the phenotypic selection of the flower characteristics of the two species of Pedicularis by female fitness showed that the number of inflorescence of the two species was subject to directional selection, indicating that the greater the number of inflorescence, the higher the fitness of the individual. The rewards traits of them were not subject to directional selection. The plant height of P. semitorta was also subject to directional selection, indicating that individual plants with higher plant heights could also produce more seeds. The results of a nonlinear selection analysis showed that the inflorescence number, flower size and helmet height of P. kansuensis were affected by a related selection, indicating that the plant individuals with more inflorescence and smaller flowers and plants with more inflorescence and higher helmet manifested a higher female fitness.The average amount of nectar per flower was subject to a significant split selection, indicating that either lower or higher nectar amounts would increase the female fitness of individual plants. There was no significant correlation selection on both the flower characteristics and flower rewards of the two species of Pedicularis.