紫花苜蓿根系构型和力学特征对生长时间的响应  

Changes in Medicago sativa root system architecture and mechanical characteristics during the growing period

作　　者：王光沛 魏艳 谌芸[1] WANG Guang-pei;WEI Yan;CHEN Yun(College of Resources and Environment,Key Laboratory of Soil and Water Conservation and Ecological Restoration of Chongqing,Southwest University,Chongqing 400715,China)

机构地区：[1]西南大学资源环境学院,水土保持生态修复重庆市重点实验室,重庆400715

出　　处：《草业学报》2025年第4期82-92,共11页Acta Prataculturae Sinica

基　　金：国家自然科学基金项目(42377324);西南大学教育教学改革研究项目(2022JY074);重庆市教委科学技术研究项目(KJQN202100218)资助。

摘　　要：为探究紫色土区紫花苜蓿根系构型和力学特征随生长时间的变化规律,于播种后60、90、120和150 d时采集整株根系进行扫描获取形态与拓扑参数,并进行整株抗拔和单根抗拉试验分别获得根系抗拔和抗拉强度。结果表明:1)随生长时间增加,紫花苜蓿的总根长、总根表面积、总根体积和根尖数均显著增加,其中根长和根尖数增长速率最高的时间段为90~120 d,根表面积和根体积为120~150 d,根系的分形维数和分形丰度亦显著增加,150 d相较于60 d时分别增加了7.50%、28.63%;2)根系抗拔/拉强度与根系直径呈负幂函数关系,且同一直径的根系抗拔/拉强度随生长时间增加先增大后减小,峰值分别出现在90和120 d;3)相关分析表明土壤自然含水率与紫花苜蓿根系抗拔/抗拉强度呈极显著正相关(P<0.01),>0.25 mm水稳性团聚体含量与平均连接长度呈显著负相关(P<0.05),冗余分析显示根系分形丰度和分形维数对根系抗拔/拉强度的贡献较显著(P<0.05),分别为75.1%和13.6%。研究结果可为紫色土区坡地水土流失治理中紫花苜蓿科学应用和效果预测提供一定的理论依据。The aim of this study was to explore the variations in root system architecture and mechanical characteristics of Medicago sativa plants in a purple soil area during the growing season after sowing.The whole root system was collected from M.sativa plants at 60,90,120 and 150 days after sowing,and the morphological and topological parameters were measured.The root pull-out strength and tensile strength were determined by pull-out resistance tests and single root tensile tests,respectively.It was found that:1)The total root length,total root surface area,total root volume,and number of root tips of M.sativa increased significantly during the growing period.The greatest increase in root length and largest increase in the number of root tips was between 90 d and 120 d,whereas the largest increases in root surface area and root volume were between 120 d and 150 d.The fractal dimension and fractal abundance of M.sativa roots were significantly higher,by 7.50%and 28.63%,respectively,at 150 d than at 60 d.2)There was a negative power function relationship between root pull-out/tensile strength and root diameter,and the root pull-out/tensile strength of roots of the same diameter increased initially and then decreased during the growing period,with the highest values at 90 d and the lowest values at 120 d.3)Correlation analyses showed that the soil water content was significantly positively correlated with the pull-out or tensile strength of M.sativa roots(P<0.01),and the proportion of>0.25 mm water-stable aggregates was negatively correlated with the average link length(P<0.05).The results of a redundancy analysis showed that the fractal abundance and fractal dimension of roots contributed significantly to the pull-out or tensile strength of M.sativa roots(P<0.05),with respective contributions of 75.1%and 13.6%.The results of this study provide a theoretical basis for the use of M.sativa to control soil erosion in purple soil areas and to predict its effectiveness in this role.

关 键 词：水土流失 草本植物 根系形态 分形丰度 抗拉强度 

分 类 号：S54[农业科学—作物学]