Abstract The aim of the present study was to compare a relatively large number of native plant species from salt-affected coastal habitats with respect to their Na+ and K+ accumulation capacity and electrolyte level in leaves. Sampling sites (77 in total) were chosen during field survey in coastal habitats located at geographically distant places along the Baltic Sea in the territory of Latvia, Estonia, Denmark and Sweden. The main criterion for selection of sampling sites was minimum average soil electrical conductivity (EC) above 200 mS m–1. Leaf samples of 102 taxa (species) from 34 families were collected, with a total number of samples reaching 502, and their water content, Na+ and K+ concentration, and electrical conductivity in water extracts were analyzed. High intraspecies and interspecies variability in analyzed parameters was found. Frequency distribution of Na+ concentration showed highly significant positive asymmetry and deviation from normality. Data on K+ concentration and tissue EC level had asymmetric distribution and deviation from normality but to a lesser extent than that for Na+. Correlation between tissue Na+ concentration and substrate EC at sampling sites was low on individual sample basis but increased to moderate level when mean values of species were analyzed. According to accumulation characteristics of Na+ and K+ in leaves, all species corresponded to one of three general groups: Na+ excluders, regulating EC by changes in K+ concentration; K+ excluders, regulating EC by changes in Na+ concentration; and tight EC regulators; but these features were evident only when intraspecies variability was considered. Na+ concentrations in a range 18 to 30 g kg–1 (on dry biomass basis) and 0.24 to 0.30 mol L–1 (on tissue water basis) can be used as approximate values of a "normal" vs "hyperaccumulation" Na+ range in leaves of coastal plant species of the Baltic Sea.

中文翻译：

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波罗的海受盐影响的沿海栖息地植物物种的叶钠、钾和电解质积累能力：对钠超积累的定义

摘要 本研究的目的是比较来自受盐影响的沿海栖息地的大量本地植物物种的 Na+ 和 K+ 积累能力以及叶片中的电解质水平。抽样地点（总共 77 个）是在拉脱维亚、爱沙尼亚、丹麦和瑞典领土上位于波罗的海沿岸地理上较远地方的沿海栖息地进行实地调查时选择的。选择采样点的主要标准是高于 200 mS m-1 的最小平均土壤电导率 (EC)。收集了34科102个类群（种）的叶样，总样本数达到502个，分析了它们的含水量、Na+和K+浓度以及水浸液中的电导率。发现分析参数存在高种内和种间变异性。Na+ 浓度的频率分布显示出非常显着的正不对称性和偏离正态性。K+ 浓度和组织 EC 水平的数据具有不对称分布和正态性偏差，但程度低于 Na+。采样点的组织 Na+ 浓度和底物 EC 之间的相关性在个体样本基础上较低，但在分析物种平均值时增加到中等水平。根据叶片中 Na+ 和 K+ 的积累特征，所有物种对应于三个通用组之一： Na+ 排除剂，通过 K+ 浓度的变化调节 EC；K+ 排除剂，通过改变 Na+ 浓度来调节 EC；和严格的欧盟监管机构；但只有在考虑种内变异性时，这些特征才明显。