塔克拉玛干沙漠腹地几种植物根系分形特征  

Root fractal characteristics at the hinterland of Taklimakan Desert

作　　者：杨小林[1,2] 张希明[1] 李义玲[1,2] 解婷婷[1,2] 王伟华[1,2,3] 

机构地区：[1]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 [2]中国科学院研究生院,北京100039 [3]山东黄河三角洲国家级重点保护区管理局科研站,山东东营257091

出　　处：《干旱区地理》2009年第2期249-254,共6页Arid Land Geography

基　　金：中国科学院知识创新工程重要方向性项目(KZCX3-SW-342-02);科技部"西部开发科技行动"重大项目(2004BA901A21-1)共同资助

摘　　要：在塔克拉玛干沙漠腹地采用全根挖掘法挖掘河西菊(Hexinia polydichotoma(Ostenf.)H. L.Yang)、沙拐枣(Calligonum roborovskii A.Los.)、罗布麻(Apocynum venetum L.)、阿克苏牛皮消(Cynanchum amplexicaule Hemsl)根系。运用分形理论对其分形特征进行研究,分析根系分支状况以及根系分形特征与拓扑特征之间的关系。研究发现:(1)在塔克拉玛干沙漠腹地,四种植物根系具有很好的分形特征,分形维数大小与拓扑参数连接总数、外部连接数之间具有较好的相关关系。(2)根丰度是描述根系在土层中扩展能力的有效指标,与根系长度、平均连接长度之间具有很好的指数关系分别可以用以下方程表示:y_1=2.7 694e^(1.5 496x),y_2=0.0 369e^(2.0 267x)(其中y_1、y_2分别为总根长、平均连接长度,R^2分别为:0.9 353、0.9 832),根丰度直接反映了根系空间占有能力与营养物质的吸收效率。通过对塔克拉玛干沙漠腹地四种植物根系分支状况与分形特征的研究表明,分形理论可以很好的反映根系空间占有能力与资源吸收效率,所以说分形理论是对根系几何、功能特征进行定量化研究的有效方法。Fractal geometry is a potential new approach to the analysis of root architecture, which may offer improved ways to quantify and summarize root system complexity as well as yield ecological and physiological insights into the functional relevance of specific architectural patterns. Fractal analysis is a sensitive measure of root branching intensity and fractal dimension expresses the ＇ space filling＇ properties of a structure. The paper was to find out the fractal characteristics of root system in the hinterland of the Taklimakan Desert. The whole root system of four natural species was excavated and exposed with shovels in 2006. These species includes： Hexinia polydichotoma （ Ostenf. ） H. L. Yang, Calligonum roborovskii A. Los. , Apocynum venetum L. and Cynanchum amplexicaule Hemsl. The results indicated that the root system has characteristics of a fractal object in the hinterland of the Taklimakan Desert and showed the relationship between fractal dimension and topological parameters. It also showed a significant relationship between fractal abundance and total root length, average link length respectively： Y1 = 2.769 4e^1.5496 （y1 is total root length,R^2 =0. 935 3）, Y^2 = 0. 036 9e^2.0267x （y2 is average link length,R^2 =0.983 2）, fraetal abundance is associated with the size of the root system and extent of soil explored while fractal abundance is associated with the nutrient absorption efficiency. The conclusions illuminated that fractal theory may well reflect the root volume of space explored and resource absorption efficiency and is a useful and practical descriptor for quantitative study of root geometric, functional features.

关 键 词：塔克拉玛干沙漠 根系 分形维数 根丰度 拓扑参数 

分 类 号：Q948[生物学—植物学]