摘要
以半干旱矿区常见植物小叶锦鸡儿为试材,采用离体条件下,对1.5~3.5mm根径范围直根施加瞬时损伤拉力(70%的极限拉力)或瞬时损伤折力(70%的极限折力),待其自修复5个月后,研究拉力、折力损伤对小叶锦鸡儿生物和力学自修复特征的影响,以期探究拉力、折力损伤对植物根系持续固土效能。结果表明:小叶锦鸡儿直根受损自修复后存活率高于65%、根径增长率高于18%;修复前后极限抗拉强度差异:平行对照(42.29±4.81)MPa>受拉自修复5个月后(33.64±3.30)MPa>受损前(28.57±3.03)MPa;抗折强度差异:平行对照(48.72±2.26)MPa>受折自修复5个月后(44.37±2.36)MPa>受损前(37.60±5.96)MPa;两类损伤力相比:拉力损伤对直根生长限制效应显著,存活率、增长率均较低,且抗折强度均显著高于抗拉强度,说明小叶锦鸡儿根系持续承受土体沉降能力强于抵抗大风拉拔能力;较细直根(径级1.5~2.4mm)受损自修复后的存活率是较粗直根(径级2.5~3.5mm)的0.99倍,根径增长率是较粗直根的1.32倍,强度下降率是较粗直根的0.81倍,较细直根自修复后生长状况和力学特性均优于较粗直根。
The Caragana microphylla Lam which is the common plant in the semi-arid mining area was used to the study object.In a nonisolated state,the damage tensile force(70% ultimate tensile force)or damage fracture force(70% ultimate fracture force)was applied in the straight roots of 1.5-3.5 mm root diameters range.After 5 months of self-healing,the self-healing characteristics of biological and mechanical were researched.In order to explore the effect of tensile and fracture damage on the sustainable soil fixation of plant roots.The results showed that the survival rate of the straight roots of Caragana microphylla Lam.was higher than 65%,and the growth rate of root diameter was higher than 18%.The difference of anti-tensile strength,control group(42.29±4.81)MPa>after 5 months of self-healing(33.64±3.30)MPa>before damage(28.57±3.03)MPa.The difference of anti-fracture strength:control group(48.72±2.26)MPa>after 5 months of self-healing(44.37±2.36)MPa>before damage(37.60±5.96)MPa.Comparison between two types of damage the effect of tensile force damage on the growth of straight root was significant.The survival rate and root diameter growth rate were lower.The anti-fracture strength was significantly higher than the antitensile strength,it indicated that the root of Caragana microphylla Lam resistance to soil settlement was stronger than the resistance to strong wind pull force.The survival rate of thinner straight roots(diameter 1.5-2.4 mm)after self-healing was 0.99 times of thicker straight roots(diameter 2.5-3.5 mm).It′s root diameter growth rate was 1.32 times of thicker taproots.And the decline rate of strength was 0.81 times of thicker straight roots.The growing states and mechanical properties of the thinner straight roots after self-healing were better than those thicker straight roots.
引文
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