Holtsford Timothy P, Ellstrand Norman C
Division of Biological Sciences, University of Missouri, Columbia, MO, 65211, USA.
Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521, USA.
Evolution. 1992 Feb;46(1):216-225. doi: 10.1111/j.1558-5646.1992.tb01996.x.
Clarkia tembloriensis exhibits a wide range of variation among its natural populations in outcrossing rate and in separation of male and female function in space (anther-stigma separation or herkogamy) and in time (protandry). Here we show that outcrossing rate is highly correlated with protandry and anther-stigma separation. Both genetic and environmental variation contribute to inter- and intrapopulation variation in protandry and anther-stigma separation. Interpopulation differentiation for protandry and anther-stigma separation was found to be polygenic. Genetic variation for protandry and anther-stigma separation within populations was demonstrated by a significant among-family variance in two populations with contrasting breeding systems. Environmental effects on the expression of mating system traits were manifested in two ways. First, significant variation among lathhouse benches suggests that small-scale environmental heterogeneity may affect the development of floral traits. Second, protandry was shortened under hot summer conditions. Hence, hotter and drier habitats, typical of the more self-pollinating populations of C. tembloriensis, can promote self-pollination purely through environmental effects.
特姆布勒氏克拉克花（Clarkia tembloriensis）在其天然种群中，异交率以及雄性和雌性功能在空间上的分离（花药与柱头的分离或雌雄异位）和时间上的分离（雄性先熟）方面表现出广泛的变异。我们在此表明，异交率与雄性先熟以及花药与柱头的分离高度相关。遗传变异和环境变异都对雄性先熟和花药与柱头分离的种群间及种群内变异有所贡献。发现雄性先熟和花药与柱头分离的种群间分化是多基因的。在具有不同繁育系统的两个种群中，家族间显著的方差证明了种群内雄性先熟和花药与柱头分离存在遗传变异。环境对交配系统性状表达的影响通过两种方式表现出来。第一，温室苗床间的显著变异表明小规模的环境异质性可能会影响花部性状的发育。第二，在炎热的夏季条件下雄性先熟期缩短。因此，特姆布勒氏克拉克花更多自花授粉种群典型的更炎热干燥的栖息地，可纯粹通过环境效应促进自花授粉。
