Morphological investigation of desert shrubs of China's Junggar Basin based on allometric theory
基于异速生长理论的准噶尔盆地荒漠灌丛形态研究

Aims Our objectives were to investigate how shape and structure affect shrub architecture and to understand its function in the desert ecosystem through simulating differences in crown architecture of desert shrubs in China’s Junggar Basin. Methods We analyzed shrub height and crown form. The difference between observed crown area and height and the estimated crown model was found to be a good measure of degree of crown development. A Malthusian conceptual model is proposed where crown area and height modify the crown architecture, shrub surface area and volume. We assumed that the three-dimensional structure of desert shrubs is the triaxial ellipsoid and chose shrub desert island in Junggar Basin as our object of study. According to plant allometric theory, we started from the differential form of the Malthusian equation and set up models describing (a) crown area and height growth and (b) surface area and volume growth. In addition, simulations were used for calculating the potential crown architecture of the desert shrub. Important findings The assumption that the vertical distribution of desert shrub crown shape is semi-triaxial ellipsoid is valid. Three crown types were identified: flat, nearly hemispherical, and upright. These crown types corresponded well with the vertical distribution patterns of maximum height. The consistency of quantitative relationship between volume and surface area of desert shrubs is suggested as a useful tool for characterizing similar water-use strategy in the same environmental condition.