[Root architecture of two desert plants in central Hexi Corridor of Northwest China]

In this study, the root systems of desert plant species Reaumuria soongorica and Nitraria tangutorum in the central Hexi Corridor of Northwest China were excavated by shovel, and the characteristics of the plant root architecture were analyzed by using topology and fractal theory. The root topological indices of the two desert plants were small, and the root branching patterns were herringbone-like. The roots of the two desert plants had obvious fractal characteristics, with the fractal dimension of R. soongorica and N. tangutorum being (1.18 +/- 0.04) and (1.36 +/- 0.06), respectively. The root fractal dimension and fractal abundance were significantly positively correlated with the root average link length. The root average link lengths of the two plants were long, which enlarged the plants' effective nutrition space, and thus, made the plants adapt to the dry and infertile soil environment. The sums of the root cross-sectional areas before and after the root bifurcation of the two desert plants were equal, which verified the principle of Leonardo da Vinci. A total of 17 parameters of root architecture were analyzed by the principal component analysis. The parameters of root topological structure, numbers of root links, stepwise branching ratio, and root diameter could well present the root architecture characteristics of the two desert plants.