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Analysis of root fractal character in the hinterland of
Taklimakan desert, China
Yang Xiaolin
a, b*
,Zhang Ximing
a
,Li Yiling
a,b
,Xie Tingting
a,b
,Wang Weihua
a,b
,
Ma Jianbing
a,b
a
Xinjiang Institute of Ecology and Geography,Chinese Academic of Science,Urumqi (830011)
b
Graduate University of the Chinese Academy of Science,Beijing(100039)
E-mail:xiaolin4577@sina.com
Abstract
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. Otherwise, fractal
analysis is a sensitive measure of root branching intensity and fractal dimension expresses the ‘space
filling’ properties of a structure. The objective of this study was to find out the fractal characteristics of
root system in the hinterland of Taklimakan desert in China. The whole root system of two naturally
species was excavated and exposed with shovels in 2007.These species includes: Tamarix
taklamakanensis, alligonum roborovskii.
A one-factorial ANOVA with species as factor showed a highly significant effect on fractal
dimension, the difference of fractal dimension indicates the otherness of root branching pattern.
The regression between link diameter and q,
a
were not significant for either species .So the ratio of the
sum of root cross-sectional areas after a bifurcation to the cross-sectional area before bifurcation,
a
and the distribution of the cross-sectional areas after bifurcation ,q are the ubiquitous characters of
root system. In this paper ,we find the significant linear relationships between the diameter after
branching and root length, biomass respectively, because root branching is self-similar and branching
rules are the same for roots of all sizes, root lengths,root biomass for the root systems of whole trees
can then be estimated by measuring the diameter of each root at the base of the trunk or diameter after
branching. The study showed that diameter of each root at the base of the trunk or diameter after
branching are effective indexes which can measured easily to estimate the root lengths, biomass and
other parameters of root architecture.
Keywords: Taklimakan desert,root system,root architecture,fractal dimension,root length,root
biomass
Plant root systems are a major carbon sink as uptake organs for water and nutrients, and the interface
between plants and the soil system, roots govern many competitive interactions (Fitter, 1987, 1991;
Casper and Jackson, 1997). At a larger scale, roots influence processes important at the ecosystem level,
such as soil erosion and carbon cycling (Andrew D. Richardson and Heinrich Zu Dohna, 2003). The
size, structure, and extent of root systems control many of these functions, so it became a hotspot in
underground ecology research (J S Huo, 2004).
However, root systems of plants in general and trees in particular are notoriously difficult to measure
because of the difficulty in excavating large volumes of soil (Böhm W., 1979). Estimation of root
lengths and root biomass for tree root systems using conventional methods is invariably a difficult and
laborious task (Smith, D.M., 2001). How to research the root architecture by relating easily measurable
parameters were attended in recent literatures (Andrew D. Richardson, 2003; Armin L. Oppelt, 2001;
Eduardo Salas, 2004)
The root architecture reflects the plant’s adaptive ability to make best use of unevenly distributed
soil resources (Fitter, 1994). There are various means for determining the size of root systems (A. Eshel,
1998; Box, 1996) and the principles of fractal geometry seem appropriate for the description of root
systems because the repetitive branching of roots leads to a certain degree of self-symmetry. Such
*Corresponding author: Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, No. 40-3
South Beijing Road, Urumqi 830011, China.