The relationship between modular growth of Kingdonia uniflora and the environment
ZHANG Wen-Hui, WANG Yan-Ping, LIU Guo-Bin
Biodiv Sci. 2003, 11 (2):
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Kingdonia uniflora is a perennial herb, a typical clonal plant that is an endemic and endangered plant in China. It is distributed in the middle and high mountains at altitudes of 2500-3900 m in Shaanxi, Gansu, Sichuan, and Yunnan Provinces. Its open dichotomously-veined leaves, as well as other primitive characters, have attracted the interest of botanist. In order to explore the conservation strategy and counter measures to threats, the growth course of every module, including root, rhizome and leaf, of K.uniflora in Taibai Mountain were studied systematically, and the environmental factors that influence populations were analyzed. The growth patterns of modules of different K. uniflora populations had a similar tendency, which could be expressed by the equation:y=A+B1x+B2x2+B3x3,where y is modular growth parameters,xis age, and A and B are constants. The modular growth parameters (root, rhizome and leaf) of K.uniflora populations in different communities were significantly different (P< 0.05).The number and the architectural index of root, rhizome and leaf developmental growth of K.uniflora populations in Abies fargesii communities at altitudes of 2700～2900m was better than that of populations in Betula utilis communities at altitudes of 2500～2700 m and in Larix potaninii var. chinensis communities at altitudes of 2900～3100 m. The habitat in Abies fargesii community was most favorable for K. uniflora populations, whereas the L. potaninii var. chinensis community was moderately favourable, and Betula utilis community was marginal. From principal component analysis (PCA) of the nine main environmental factors that influenced the modular growth of K. uniflora populations, human disturbance, climate (illumination, air temperature and humidity), and soil condition (pH and moisture), were shown to be the most important factors. In addition, the thickness of humus and the organic content of soil, and the coverage of the community also played important roles. Reflecting the importance of asexual propagation in the life of K. uniflora and the special range of dependent environmental variables, more attention should be paid on protecting and building favorable environmental conditions. Disturbance by human beings should be stopped. The habitat of communities of Abies fargesii, Betula utilis, and L. potaninii var. chinensis, where K. uniflora populations live should be conserved. The action of blindly transferring individuals of K. uniflora from the wild to the garden should not be promoted.