盐渍土壤生境中大果沙枣成年树离子吸收、运输和分配特征研究

为揭示盐渍土壤中大果沙枣(Elaeagnus angustifolia Linn.)树体矿质离子分布规律,保障大果沙枣高效种植和丰产栽培,以不同盐度土壤中生长的成年大果沙枣树为材料,测定并分析了其根、枝、叶中Na⁺、K⁺、Mg²⁺和Ca²⁺的吸收、运输和分配特征。结果表明：盐土土壤环境中,大果沙枣叶片对Ca²⁺和Mg²⁺具有较强的选择吸收能力,低盐（I~II级）土壤环境中,叶内Na⁺含量明显上升,而至高盐（III~IV级）中,根部对Na⁺的吸收量明显高于枝和叶。随着林地土壤盐度的升高,K⁺、Ca²⁺、Mg²⁺在枝部和叶部的积累量明显增大,矿质离子由根部向枝、叶部运输的能力在I~III级盐度土壤环境中逐渐增大,并在IV级盐度土壤环境中受抑。同时,根和枝中K⁺/Na⁺和Mg²⁺/Na⁺值均是先增大后减小,叶中K⁺/Na⁺、Mg²⁺/Na⁺变幅较小,根和叶中Ca²⁺/Na⁺变幅较大。大果沙枣成年树的盐适应机制主要是通过根对Na⁺的聚积作用,叶对K⁺、Mg²⁺和Ca²⁺的选择性吸收能力增强来实现的,同时也与枝中相对稳定的K⁺、Na⁺、Mg²⁺和Ca²⁺的选择性运输能力有关。

Research on the Ion Absorption,Transportation and Distribution of Mature E. angustifolia in Saline Soil Habitat

To reveal the rule of mineral ions distribution of the Elaeagnus angustifolia Linn. in saline soil habitat to ensure the efficient planting and high yield, mature E. angustifolia grown in different salinity soils were used as study materials, the characteristics of absorption, transport and distribution of Na⁺, K⁺, Mg²⁺and Ca²⁺ in roots, branches and leaves were analyzed. The results showed that in saline soil environment, leaves of E. angustifolia had strong selective absorbing capacity for Ca²⁺ and Mg²⁺. In lower salt (from Grade I to II) soil environment, the Na⁺ content in leaves increased significantly, while in higher salt (from Grade III to IV) situation, Na⁺ absorbed in roots was more than that in branches and leaves. With the increase of soil salinity, the accumulation of K⁺, Ca²⁺ and Mg²⁺ in branches and leaves increased significantly. The capacity of mineral ions transportation from roots to branches and leaves increased in Grade I-III salinity soil environment, and this capacity was inhibited in Grade IV salinity soil environment. The values of K⁺/Na⁺and Mg²⁺/Na⁺in roots and branches increased first and then decreased. K⁺/Na⁺ and Mg²⁺/Na⁺ value in leaves had little variation, and the Ca²⁺/Na⁺ value in the roots and leaves varied greatly. The salt adaptation mechanism of mature E. angustifolia is mainly achieved by the accumulation of Na⁺ in roots and the enhanced selective absorbing capacity of K⁺, Mg²⁺ and Ca²⁺ in leaves, and also related to the relatively stable selective transport capacity of K⁺, Na⁺, Mg²⁺ and Ca²⁺in branches.