不同盐碱化草地披碱草生物量形成及根系对K+、Na+的选择性吸收

于2008年7月选取轻度、中度和重度盐碱草地种植披碱草(Elymus dahuricus),通过测定植株地上部与地下部的Na⁺、K⁺、Ca²⁺、Mg₂⁺、Fe²⁺、Zn²⁺含量、K⁺-Na⁺运输选择性系数、地上、地下生物量及粗蛋白(CP)含量,研究不同盐碱化草地对披碱草生长及离子含量的影响,以期为耐盐碱饲草选育及盐碱地生物治理提供理论参数和实践依据。结果表明:随土壤盐碱化程度的增强,披碱草地上部、地下部Na+含量显著增加(P<0.05),K+含量显著降低(P<0.05),根系的选择性运输能力显著下降(P<0.05);不论盐碱胁迫的强度如何,披碱草地上部始终较地下部保持较高的K+/Na+值;地上、地下生物量,CP含量均随盐碱度的增加呈显著下降趋势(P<0.05)。因此,披碱草地上部保持较高的K⁺含量和K⁺/Na⁺比值可能是其耐盐碱的重要机制。

Biomass Formation and Selective Absorption for K+/Na+ of Elymus dahuricus Grown in Different Saline Grassland

In order to explore the mechanism of saline tolerance of Elymus dahuricus and supply the theoretical and practical basis,Elymus dahuricus was planted in three plots which were classified as light,moderate,and heavy in salinization and alkalization in July,2008.Contents of Na⁺,K⁺,Ca²⁺,Mg²⁺,Fe²⁺,and Zn²⁺ in shoots and roots of Elymus dahuricus,the transport selectivity of K⁺ and Na⁺,and aboveground and underground biomass and crude protein(CP) content were measured.Furthermore,effects of different saline grassland on mineral elements content and growth of Elymus dahuricus individuals were analyzed.The results showed that,with increasing degree of soil salinization,Na⁺ content in shoots and roots of Elymus dahuricus increased significantly,and K⁺ content in shoots and roots of Elymus dahuricus decreased significantly,and capacities of selective transport of Elymus dahuricus roots decreased significantly.K⁺/Na+was always higher in aboveground part than in underground part of plants in all three plots.In the opposite,aboveground and underground biomass and CP content of Elymus dahuricus decreased significantly.Based on the experimental data,we can conclude that the high content of K⁺ and the high ratio of K⁺/Na⁺ in aboveground might be one of the mechanisms for saline tolerance of Elymus dahuricus.