Meng Jingxiang, Mao Jian-Feng, Zhao Wei, Xing Fangqian, Chen Xinyu, Liu Hao, Xing Zhen, Wang Xiao-Ru, Li Yue
State Engineering Laboratory of Forest Tree Breeding, Key Laboratory of Genetic and Breeding in Forest Trees and Ornamental Plants, Beijing Forestry University, Beijing, China; College of Biology Sciences and Technology, Beijing Forestry University, Beijing, China.
State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2015 Mar 10;10(3):e0118501. doi: 10.1371/journal.pone.0118501. eCollection 2015.
Evidence from molecular genetics demonstrates that Pinus densata is a natural homoploid hybrid originating from the parent species Pinus tabuliformis and Pinus yunnanensis, and ecological selection may have played a role in the speciation of P. densata. However, data on differentiation in adaptive traits in the species complex are scarce. In this study, we performed a common garden test on 16 seedling traits to examine the differences between P. densata and its parental species in a high altitude environment. We found that among the 16 analyzed traits, 15 were significantly different among the species. Pinus tabuliformis had much earlier bud set and a relatively higher bud set ratio but poorer seedling growth, and P. yunnanensis had opposite responses for the same traits. P. densata had the greatest fitness with higher viability and growth rates than the parents. The relatively high genetic contribution of seedling traits among populations suggested that within each species the evolutionary background is complex. The correlations between the seedling traits of a population within a species and the environmental factors indicated different impacts of the environment on species evolution. The winter temperature is among the most important climate factors that affected the fitness of the three pine species. Our investigation provides empirical evidence on adaptive differentiation among this pine species complex at seedling stages.
分子遗传学证据表明，高山松是油松和云南松这两个亲本物种天然形成的同倍体杂种，生态选择可能在高山松的物种形成过程中发挥了作用。然而，关于该物种复合体适应性性状分化的数据却很稀少。在本研究中，我们针对16个幼苗性状进行了共同园试验，以考察高山松及其亲本物种在高海拔环境中的差异。我们发现，在分析的16个性状中，有15个在物种间存在显著差异。油松的芽形成时间早得多，芽形成率相对较高，但幼苗生长较差，而云南松在相同性状上的反应则相反。高山松具有最高的适合度，其活力和生长速率均高于亲本。种群间幼苗性状相对较高的遗传贡献表明，每个物种内部的进化背景都很复杂。一个物种内种群的幼苗性状与环境因子之间的相关性表明，环境对物种进化有不同的影响。冬季温度是影响这三种松树适合度的最重要气候因子之一。我们的调查为该松树物种复合体在幼苗阶段的适应性分化提供了实证依据。
