青藏高原东北部4种灌木主根和侧根抗拉力学特性比较

目的]开展青藏高原东北部黄土区4种灌木植物主根和侧根抗拉力学强度试验,探讨主根和侧根抗拉力学特性关系,为深入研究植物根系固土护坡力学机理提供参考。方法]选取西宁盆地长岭沟流域作为研究区,对生长期为3 a的柠条锦鸡儿(Caragana korshinskii)、中宁枸杞(Lycium chinense)、白刺(Nitraria tangutorum)和霸王(Sarcozygium xanthoxylon)4种优势灌木主根和侧根进行室内单根拉伸试验,确定其主根和侧根抗拉力、抗拉强度和杨氏模量及其与根径之间的关系;在此基础上,进一步分析了4种灌木主根和侧根根径、抗拉力、抗拉强度和杨氏模量之间的关系。结果]柠条锦鸡儿、中宁枸杞、白刺和霸王主根抗拉力分别为侧根的28.45,13.21,11.01,7.35倍,主根抗拉强度分别为侧根的0.67,1.17,0.68,1.22倍,主根杨氏模量分别为侧根的2.00,2.39,2.82,2.48倍。结论] 4种灌木植物主根抗拉力均显著大于侧根;柠条锦鸡儿和白刺主根抗拉强度小于侧根,而中宁枸杞和霸王主根抗拉强度大于侧根;4种灌木植物主根杨氏模量显著大于侧根,说明其主根相对于侧根不易发生形变,对边坡浅层稳定性贡献亦显著于侧根。

Comparison of Tensile Resistance Properties of Main Roots and Lateral Roots Among Four Shrub Species in Northeast Qinghai-Tibet Plateau

Objective] The tensile strength tests were carried out of the main roots and lateral roots of four shrub species in the loess area of Northeast Qinghai-Tibet Plateau, and the relationship between mechanical properties of main roots and lateral roots was discussed, which provided a reference for investigating the mechanical mechanism of plant roots in stabilizing soils and slopes.Methods] The drainage area of Changlinggou in Xining Basin was selected as the studying area, and the tensile force, tensile strength, Young''s modulus were measured by laboratory single root tensile test of four three-year-old shrub species(Caragana korshinskii, Lycium chinense, Nitraria tangutorum and Sarcozygium xanthoxylon).Then the relationship between root diameter, tensile force, tensile strength and Young''s modulus of main roots and lateral roots of four species was further analyzed.Results] The tensile forces of main roots of C. korshinskii, L. chinense, N. tangutorum and S. xanthoxylon were 28.45, 13.21, 11.01 and 7.35 times of lateral roots, the tensile strengths of main roots were 0.67, 1.17, 0.68 and 1.22 times of lateral roots, and the Young''s moduluses of main roots were 2.00, 2.39, 2.82 and 2.48 times of lateral roots, respectively.Conclusion] The tensile forces of main roots were significantly higher than lateral roots for four shrub species. The tensile strengths of main roots of C. korshinskii and N. tangutorum were lower than lateral roots, while the tensile strengths of main roots of L. chinense and S. xanthoxylon were higher than lateral roots. The Young''s moduluses of main roots were significantly higher than lateral roots for four species, it showed that the main roots were not easy to deform in comparison with the lateral roots, and the contribution of main roots to the stability of the shallow slope is significantly higher than lateral roots.