Analysis of the Population Spatial Distribution Pattern and Root Characters of Arnebia euchroma in Yili Area

Objective To investigate the spatial point pattern of the population of Arnebia euchroma ，and to analyze the relationships between the population density and altitude，and between the sum of rhizome diameter and the total root weight after drying. Method Based on the investigation step by step in the mountain，five quadrates with 10 m×10 m of Arnebia euchroma were selected to locate each plant cluster’s position.The Ripley’s K（r）function and regression function were used. Result （1） Arnebia euchroma is mainly growing in alpine mountains of Zhaosu and Tekes counties with altitude above 2 099 m，Yili State，Xinjiang Uygur Autonomous Region.（2） A. euchroma population shows cluster distribution at low altitude（relatively），random distribution at medium altitude，and random-cluster-random distribution at high altitude.（3）The relationship between population density and altitude could be stated with a quadratic function （ R 2=0.952 0， P R 2=0.953 9， P Conclusion The open sunny slope is a necessary but not sufficient condition for A. euchroma growing.The random or cluster distribution pattern of A. euchroma could guide the selection of the field for wild tending or imitating wild cultivation.The linear relationship between the root weight and the root diameter of A. euchroma could be used to estimate the root reserves by measuring the root diameter of living plants.