Soil salinity diminishes the dominance of species and affects their distribution. Phragmites australis is a dominant ecosystem engineer with broad distribution, high intraspecific variation and great socio-economic importance. Coastal ecosystems inhabited by P. australis are threatened by salinization. Here, we investigated salinity tolerance of freshwater and salt marsh population of the species, grown under two soil salinities and in two common gardens. Salinity significantly affected the growth, biomass, leaf physiological parameters and ion concentration. Climate altered morphology and ion concentration of P. australis. In contrast to our hypothesis, the salt marsh population was not more salt tolerant than the freshwater population, and both showed a low degree of salt stress, maintaining their photosynthesis and chlorophyll concentration, and only showing small decreases in biomass and height when salt-treated. We therefore ruled out local adaptation to soil salinity. Instead, both populations acclimated by phenotypic plasticity of biomass, root: shoot ratio, stomatal conductance and ion content. The salinity tolerance strategy of both populations was ion concentration by tissue desiccation, which was most efficient in the drier climate common garden. Hence, plants utilizing tissue desiccation as salinity tolerance strategy will have an advantage in areas where climate change leads to drier air humidity.

中文翻译：

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相对空气湿度的差异影响主要草种芦苇的淡水和盐沼种群对土壤盐分的响应

土壤盐分降低了物种的优势并影响了它们的分布。芦苇是一种主要的生态系统工程师，分布广泛，种内变异高，具有重要的社会经济意义。P. australis 栖息的沿海生态系统受到盐碱化的威胁。在这里，我们调查了该物种的淡水和盐沼种群的耐盐性，这些种群在两种土壤盐度下和两个常见花园中生长。盐度显着影响生长、生物量、叶片生理参数和离子浓度。气候改变了 P. australis 的形态和离子浓度。与我们的假设相反，盐沼种群并不比淡水种群更耐盐，并且两者都表现出低程度的盐胁迫，维持了它们的光合作用和叶绿素浓度，并且仅在盐处理时显示生物量和高度的小幅下降。因此，我们排除了当地对土壤盐分的适应。相反，两个种群都通过生物量的表型可塑性、根：芽比、气孔导度和离子含量来适应环境。两个种群的耐盐策略都是通过组织干燥进行离子浓缩，这在较干燥气候的普通花园中最为有效。因此，利用组织干燥作为耐盐策略的植物在气候变化导致空气湿度干燥的地区具有优势。两个种群的耐盐策略都是通过组织干燥进行离子浓缩，这在较干燥气候的普通花园中最为有效。因此，利用组织干燥作为耐盐策略的植物在气候变化导致空气湿度干燥的地区具有优势。两个种群的耐盐策略都是通过组织干燥进行离子浓缩，这在较干燥气候的普通花园中最为有效。因此，利用组织干燥作为耐盐策略的植物在气候变化导致空气湿度干燥的地区具有优势。