Singh Akanksha, Roy Sribash
Genetics and Molecular Biology Division, CSIR-National Botanical Research Institute, Lucknow, Uttar Pradesh, 226001, India.
Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi, 110 001, India.
BMC Ecol. 2017 Dec 13;17(1):39. doi: 10.1186/s12898-017-0149-5.
Population differentiation and their adaptation to a particular environment depend on their ability to respond to a new environment. This, in turn is governed to an extent, by the degree of phenotypic plasticity exhibited by the populations. The populations of same species inhabiting different climatic conditions may differ in their phenotypic plasticity. Himalayan populations of Arabidopsis thaliana originating from a steep altitude are exposed to different climatic conditions ranging from sub-tropical to temperate. Thus they might have experienced different selection pressures during evolution and may respond differently under common environmental condition.
Phenotypic plasticity and differentiation of natural populations of A. thaliana grown under common garden and controlled conditions were determined. A total of seventeen morphological traits, their plasticity, association between traits and environment were performed using 45 accessions from three populations. Plants from different altitudes differed in phenotypes, their selection and fitness under two conditions. Under both the conditions lower altitude population was characterized by higher leaf count and larger silique than higher and middle altitude population. Flowering time of high altitude population increased while that of low and medium altitude decreased under controlled condition compared to open field. An increase in seed weight and germination was observed for all the population under open field than controlled. Rosette area was under divergent selection in both the condition. The heritability of lower altitude population was the highest under both the conditions, where as it was the least for higher altitude population further indicating that the high altitude populations are more responsive towards phenotypic changes under new environmental conditions. Ninety-nine percent of variability in traits and their plasticity co-varied with the altitude of their origin. The population of high altitude was more plastic and differentiated as compared to the lower altitude one.
Arabidopsis thaliana population native to different altitudes of the west Himalaya responds differently when grown under common environments. The success of high altitude population is more in common garden than the controlled conditions. The significant variability in phenotype and its association with altitude of origin predicts for non-random genetic differentiation among the populations.
种群分化及其对特定环境的适应取决于它们对新环境的响应能力。而这又在一定程度上受种群表现出的表型可塑性程度的支配。栖息于不同气候条件下的同一物种的种群，其表型可塑性可能存在差异。源自陡峭海拔高度的喜马拉雅拟南芥种群，暴露于从亚热带到温带的不同气候条件下。因此，它们在进化过程中可能经历了不同的选择压力，并且在共同环境条件下可能有不同的反应。
测定了在共同园圃和受控条件下生长的拟南芥自然种群的表型可塑性和分化情况。使用来自三个种群的45份材料，对总共17个形态性状、它们的可塑性、性状与环境之间的关联进行了研究。来自不同海拔高度的植株在两种条件下的表型、选择和适合度存在差异。在两种条件下，低海拔种群的特征都是叶片数量更多、角果更大，高于中海拔种群。与露地相比，在受控条件下，高海拔种群的开花时间增加，而低海拔和中海拔种群的开花时间减少。与受控条件相比，在露地条件下所有种群的种子重量和发芽率均有所增加。莲座叶面积在两种条件下都受到趋异选择。在两种条件下，低海拔种群的遗传力最高，而高海拔种群的遗传力最低，这进一步表明高海拔种群在新环境条件下对表型变化的反应更敏感。性状及其可塑性99%的变异性与它们起源地的海拔高度共同变化。与低海拔种群相比，高海拔种群更具可塑性且分化程度更高。
原产于喜马拉雅西部不同海拔高度的拟南芥种群，在共同环境下生长时反应不同。高海拔种群在共同园圃中的表现比在受控条件下更成功。表型的显著变异性及其与起源海拔的关联预示着种群间存在非随机的遗传分化。
