3种灌木直根抗剪特性及其与化学组分的关系

Relationship between anti-shear characteristics of root and its responses to their chemical components for three shrubs

以柠条、沙柳和沙棘为研究对象,测定3种灌木根系1～4mm抗剪特性及纤维素、半纤维素、木质素、综纤维素、木纤比含量,分析其化学组分对抗剪特性的影响。结果表明:3种灌木直根抗剪力、抗剪强度均存在显著差异,种间变化为柠条(172. 68N,17. 18MPa)>沙柳(124. 99N,12. 49MPa)>沙棘(68. 49N,6.76MPa),且3种直根抗剪力与直径均呈幂函数正相关,抗剪强度与直径均呈幂函数负相关。3种灌木直根化学组分含量差异显著,其中柠条纤维素、综纤维素平均含量最高,分别为35. 92%和66. 44%;木质素、木纤比平均含量整体表现为:沙棘(48. 80%、3. 22)>沙柳(30. 16%、1. 46)>柠条(20. 58%、0. 57)。3种灌木直根抗剪强度与纤维素、综纤维素含量均呈极显著正相关,这表明纤维素和综纤维素是影响灌木根系材料力学特性的主要化学组分。

Three shrubs Caragana korshinskii,Salix psammophila and Hippophae rhamnoides were studied,and the shear resistances of taproots with a diameter of 1~4 mm and cellulose,hemicellulose,lignin,hemicellulose,wood fiber ratio were measured to analyze the influence of chemical constituent on shear resistance.Results show:the shear resistance and anti-shear strength of the taproots of the three shrubs are significantly different,specifically,Caragana(170.75 N,17.18 MPa)>Salix(124.99 N,12.49 MPa)>Sea buckthorn(68.49 N,6.76)MPa).The chemical constituent contents of the taproots of the three shrubs are significantly different.Caragana has the highest cellulose and hemicellulose content,they are 35.92%and 67.43%,respectively.The average content of lignin,wood fiber ratio is as follows:Sea buckthorn(48.80%,3.22)>Salix(0.16%,1.46)>Caragana(20.58%,0.57).The cellulose and hemicellulose contents are significantly positively related with the anti-shear strength,indicating that cellulose and hemicellulose are key factors affecting the mechanical properties of the root materials of shrubs.