Abstract：
Local adaptation is common in plant species, and knowing whether a population is locally adapted has fundamental and applied relevance. However, local adaptation in tropical plants remains largely less studied, and covering this gap is not simple since reciprocal transplantation - the gold standard for detecting local adaptation - is not feasible for most species. Here, we combined genetic, climatic and phenotypic data to investigate ecotypic differentiation, an important aspect of local adaptation, in coastal and inland populations of the orchid Epidendrum fulgens Brongn., a long-lived tropical plant for which reciprocal transplantation would not be feasible. We used nine microsatellite markers to estimate genetic divergence between inland and coastal populations. Moreover, occurrence data and climate data were used to test for differences in the realized niche of those populations. Finally, we assessed saturated water content, leaf specific area, height, and stomatal density in common garden and in situ to investigate the effects of ecotypic differentiation and plasticity on the phenotype. Coastal and inland groups\' niches do not overlap, the former occupying a wetter and warmer area. However, this differentiation does not seem to be driven by ecotypic differentiation since there was no positive correlation between genetic structure and climate dissimilarity. Moreover, specific leaf area and leaf saturated water content, which are important phenotypic traits related to soil fertility and drought stress, were rather plastic. We conclude that ecotypic differentiation is absent, since phenotypic plasticity is an important mechanism explaining the niche broadness of this species.
摘要：
局部适应在植物物种中很常见，知道人口是否适应当地情况具有基本和应用意义。然而,热带植物的局部适应研究仍然很少，弥补这一差距并不简单，因为相互移植——检测局部适应的黄金标准——对大多数物种来说是不可行的。这里,我们结合了遗传，气候和表型数据，以调查生态型分化，当地适应的一个重要方面，在兰花的沿海和内陆种群中。,一种长寿的热带植物，对其进行相互移植是不可行的。我们使用了9个微卫星标记来估计内陆和沿海种群之间的遗传差异。此外，发生数据和气候数据用于测试这些种群的已实现生态位的差异。最后,我们评估了饱和水含量，叶比面积,高度,和普通花园和原位的气孔密度，以研究生态型分化和可塑性对表型的影响。沿海和内陆群体不重叠，前者占据较湿润和较温暖的区域。然而,这种分化似乎不是由生态型分化驱动的，因为遗传结构和气候差异之间没有正相关。此外，比叶面积和叶片饱和含水量，是与土壤肥力和干旱胁迫相关的重要表型性状，相当塑料。我们得出结论，生态型分化是不存在的，因为表型可塑性是解释该物种生态位宽度的重要机制。
