Root system architecture has often been overlooked in plant research despite its critical role in plant adaptation to environmental conditions.This study focused on the root system architecture of the desert shrub Reaumuria soongorica in the Alxa steppe desert,Northwest China.Plant samples were collected during May-September 2019.Using excavation methods,in situ measurements,and root scanning techniques,we analyzed the root distribution,topology,and branching patterns of R.soongorica across an age sequence of 7-51 a.Additionally,we investigated the allometric relationships of root collar diameter with total coarse root length,biomass,and topological parameters.The results showed that the roots of R.soongorica were predominantly concentrated in shallow soil layers(10-50 cm),with lateral root branching and biomass allocation increasing with shrub age.The root topology exhibited a herringbone-like structure,with average topological and modified topological indices of 0.89 and 0.96,respectively,both of which adjusted with shrub age.The root system displayed a self-similar branching pattern,maintaining a constant cross-sectional area ratio of 1.13 before and after branching,deviating from the area-preserving rule.These adaptive traits allow R.soongorica to efficiently expand its nutrient acquisition zone,minimize internal competition,and optimize resource uptake from the upper soil layers.Furthermore,significant linear relationships were observed between log10-transformed root collar diameter and log10-transformed total coarse root length,biomass,and topological parameters.These findings advance non-destructive approaches for studying root characteristics and contribute to the development of root-related models.Besides,this study provides new insights into the adaptive strategies of R.soongorica under extreme drought conditions,offering valuable guidance for species selection and cultivation in desert restoration efforts.
为探究森林生态系统在环境变化中的生存策略,预测植物根系在长期氮沉降背景下的响应模式,在亚热带天然常绿阔叶林中设置对照和施氮[80 kg N/(hm2·a)]2个处理,研究长期氮添加对根系生物量、比根长、比表面积和组织密度等的影响。结果表明,长期的氮添加没有对根系生物量及其根系生物量消减系数β产生显著影响(P>0.05),即根系生物量的垂直分布特征并没有发生显著变化(即在不同土层积累的生物量之间没有明显差异),对照和氮处理下的不同径级的根系生物量密度随土层变化的趋势相同,但是土层和径级的交互作用会对根系生物量产生显著影响;长期氮添加显著增加0~1 mm的细根比根长;但是长期的氮添加显著降低了组织密度且不受径级的影响;而氮添加对根系比表面积无显著影响,这种变化是在群落水平上的一种整体的变化趋势。在群落水平上,长期的氮添加对亚热带常绿阔叶林根系生物量及垂直分布无显著影响,这正与土壤总碳氮磷的含量随土层变化一致。但11a的氮添加会增加比根长而降低组织密度,一些物种的根系资源获取策略会变为快速获取型策略。因此,长期的氮沉降背景下根系会通过增加比根长,降低组织密度来响应养分变化。
Plant root systems serve as a natural reinforcing material,significantly improving soil stability.Furthermore,the tensile strength of soil is crucial in mitigating the formation of cracks.Consequently,this study aims to investigate the influence of plant roots on the tensile strength of soil.For this investigation,Amorpha fruticose was selected due to its large root diameter and the ease of root extraction.Indoor tensile tests were conducted on individual roots and root-soil complexes under three varying factors.The results indicate a power law relationship between root diameter and tensile strength.Increased root content and dry density notably enhance the tensile strength of the root-soil complex while roots mitigate damage associated with soil brittleness.When root content increases from 0 to 10,the maximum enhancement in tensile strength of the root-soil complex reaches 42.3 kPa.The tensile strength of the root-soil complex at a dry density of 1.7 g/cm^(3)is four to five times greater than that of the complex at a dry density of 1.4 g/cm^(3).Moreover,as moisture content increases,the tensile strength of the root-soil complex initially rises before declining,with an increase range of 7.7-35.8 kPa.These findings provide a scientific basis for understanding the role of vegetation roots in soil tensile strength and for guiding slope reinforcement strategies.
TAO GaoliangYANG ChuanhuiCHEN QingshengNIMBALKAR SanjayXIAO HenglinWANG Qing
