川中丘陵区4种乡土阔叶树根系拓扑结构特征  

Topological characteristics of the root systems of four native broad-leaved trees in the central Sichuan hilly region

作　　者：牛牧[1,2] 陈俊华[2,3] 周大松 谢天资[2,3] 别鹏飞 赵润[4] 慕长龙 NIU Mu;CHEN Junhua;ZHOU Dasong;XIE Tianzi;BIE Pengfei;ZHAO Run;MU Changlong(College of Forestry,Beijing Forestry University,Beijing 100083,China;Sichuan Academy of Forestry,Chengdu 610081,China;Sichuan Longmenshan National Positioning Observation and Research Station for Forest Ecosystem,Pingwu 622550,China;Life Science and Technology College,Mianyang Teachers,College,Mianyang 621000,China)

机构地区：[1]北京林业大学林学院,北京100083 [2]四川省林业科学研究院,四川成都610081 [3]四川龙门山森林生态系统国家定位观测研究站,四川平武622550 [4]绵阳师范学院生命科学与技术学院,四川绵阳621000

出　　处：《南京林业大学学报（自然科学版）》2020年第2期125-132,共8页Journal of Nanjing Forestry University：Natural Sciences Edition

基　　金：“十二五”国家科技支撑计划(2015BAD07B0402).

摘　　要：【目的】林木地下根系的养分竞争影响着林木生长、物种共存和森林群落动态,了解川中丘陵区乡土阔叶树根系构型的差异性和相似性,探讨它们在土壤环境中根系的适应策略,为该区域的防护林建设与植被恢复物种选择提供参考。【方法】以川中丘陵区"带状采伐改造"采伐带内补植的4种7年生乡土阔叶树桤木(Alnus cremastogyne)、香椿(Toona sinensis)、喜树(Camptotheca acuminata)、香樟(Cinnamomum camphora)作为研究对象,选择长势良好的桤木、喜树、香椿各7株,香樟6株,测定其地径、胸径、树高和冠幅。采用50 cm×50 cm的网格确定根系的分布位置,按1∶40的比例在50 cm×75 cm的坐标纸上准确绘制出根系的俯视图。将根系全部挖出后,测定各级根系长度及分支前后的直径、各级根数目,根系内、外部连接数目,以及连接长度等指标。【结果】①桤木根系以水平分布占绝对优势(水平分布半径是垂直分布深度的2.29倍),侧根十分发达,根系浅层化;喜树主根十分发达,垂直分布深度是水平分布半径的2.71倍,但其侧根不发达;香樟和香椿则主根和侧根均十分发达。喜树、香樟和香椿均属深根性树种。根系水平分布半径除香樟和香椿间差异不显著外,其余均差异显著(df=3,F=145.007,P<0.01);而垂直分布深度除香樟和喜树间差异不显著外,其余树种间均表现为差异显著(df=3,F=99.478,P<0.05)。②不同树种的根系拓扑指数之间存在显著差异,其中修正拓扑指数(qa、qb)、拓扑指数(TI)存在极显著差异(dfqa=3,Fqa=38.007,Pqa<0.01;dfqb=3,Fqb=4.066,Pqb<0.05;dfTI=3,FTI=69.561,PTI<0.01)。桤木、香椿的根系为叉状分支结构,它们的qa、qb、TI分别为0.160、0.097、0.673和0.122、0.047、0.635;喜树、香樟的根系则趋向于鱼尾形分支结构,qa、qb、TI分别为0.582、0.547、0.885和0.364、0.266、0.799。③不同物种的根系平均连接长度差异显著(df=3,F=6.166,P<0.05)�【Objective】Nutrient competition between the underground roots of trees has profound effects on tree growth,species coexistence,and forest community dynamics.An important trait in this regard is root system architecture,which can be described in terms of the geometric morphological characteristic parameters and topological structure of root systems.In this study,in order to provide theoretical and practical references for the development of protected forests and vegetation restoration in the central Sichuan hilly region,we examined the differences and similarities of the root systems of native broad-leaved trees in this region and their adaptive strategies in the soil environment.【Method】We focused on four native broad-leaved tree species(Alnus cremastogyne,Toona sinensis,Camptotheca acuminate and Cinnamomum camphora)in the central Sichuan hilly region,which had been replanted as part of a Cupressus funebris transformation experiment based on cutting strips in cypress stands 7 years age.For analyses of growth traits,we selected seven healthy individuals of A.cremastogyne,T.sinensis and C.acuminata,respectively,six individuals of C.camphora,then measured their basal diameter,breast-height diameter,height and canopy cover.All root systems(root diameter>3 mm)were extracted and their distributions were determines using 50 cm×50 cm grids.Furthermore,we drew 1∶40-scale overhead views of the root systems using 50 cm×75 cm coordinate paper.The length of roots in each root grade,the root diameter before and after branching,root number,the interior and exterior link number of root as well as the connecting length,were measured using electronic vernier calipers and a steel tape.【Result】①The root system of A.cremastogyne was found to have a predominantly horizontal distribution(the horizontal distribution radius was 2.29 times the vertical depth).Moreover,the lateral roots of this tree are well developed and the root system is shallow.Although the main roots of C.acuminata trees were developed,with vertical

关 键 词：川中丘陵区 乡土阔叶树 林木根系 拓扑结构 适应策略 

分 类 号：S718[农业科学—林学]