寒旱环境盐胁迫条件下两种草本植物的根系力学特性研究

本项研究选取适宜于西宁盆地及其周边地区生长的2种优势草本植物垂穗披碱草(Elymus nutans Griseb)和细茎冰草(Agropyron trachycaulum (Linn.) Gaertn.)作为供试种,通过室内种植培育方式,采用浓度梯度分别为50mmol/L、100mmol/L、150mmol/L、200mmol/L的Na₂SO₄溶液对2种植物进行盐胁迫处理。在盐胁迫试验处理后的第15d、30d和45d时,分别测定2种植物单根抗拉力和单根抗拉强度。试验结果表明：相同盐胁迫浓度时,2种植物单根抗拉力随生长期增长呈逐渐增大,单根抗拉强度随生长期增加表现为逐渐降低的变化规律；相同生长期时,2种植物单根抗拉力随着胁迫液浓度由0mmol/L增加至200mmol/L时表现为逐渐减小趋势,单根抗拉强度则随着胁迫液浓度增加呈逐渐增大的变化规律；进一步研究表明,在相同胁迫浓度和相同生长期条件下,细茎冰草单根抗拉力和单根抗拉强度分别较垂穗披碱草高0.008N~0.025N和9.646MPa~72.807MPa；2种草本植物单根抗拉力与根径之间呈指数函数关系；2种草本单根抗拉强度分别随根径的增加而逐渐减小,且均与根径呈幂函数关系。本该研究成果对于进一步探讨寒旱环境盐胁迫条件下,草本植物根系力学强度特征及其变化规律具有重要理论研究价值,同时对于有效防治研究区水土流失、浅层滑坡等地质灾害的发生具有实际指导意义。

Research on mechanical characteristics of two herbaceous roots under salt stress in cold and arid environment

Two species (Elymus nutans Griseb. and Agropyron trachycaulum (Linn.) Gaertn.) which are adaptive to the growing condition of the Xining Basin and the surrounding areas were taken as the test species. Through interior cultivation method, salt stress test was applied to the two species by Na₂SO₄ solution with a concentration gradient of 50mmol/L, 100mmol/L, 150mmol/L and 200mmol/L. After being given salt stress treatment, on the 15_th day, 30_th day and 45_th day, the single tensile resistance and single tensile strength of the two plants were measured respectively. The test result exhibits: under the same salt stress concentration, as the growth of the period increased, the tensile resistance of single root of two herbs gradually increased and the tensile strength of single root decreased gradually; with the same growth period, as the concentration increased from 0mmol/L to 200mmol/L, the tensile resistance of single root of two herbs gradually decreased and the tensile strength of single root increased gradually; furthermore, at the same concentration and the same growth period, the single tensile strength and tensile strength of Agropyron trachycaulum was 0.008N~0.025N and 9.646MPa~72.807MPa higher than Elymus nutans Griseb.; the relationship between single tensile resistance and root diameter of 2 herbs was exponential function; the tensile strengths of single root for 2 herbs decreased with the increasing of root diameter, and both had power function relationship with root diameter. The study has theoretical value in further exploring characteristics and variation law of mechanical properties of herbaceous roots under salt stress in cold and arid environment. Besides, the study has practical significance in preventing and controlling geological disasters in the study area, such as soil erosion, shallow landslide.