Comparative study on mineral elements in the roots of Rheum tanguticum from Qinghai-Plateau

In the present paper,the authors analysed 10 mineral elements in the roots of Rheum tanguticum collected from 30 different habitats.The mean concentration values of the 10 elements decreased as follows:Ca＞Mg＞K＞Fe＞Mn＞Cr＞Zn＞Ni＞Cu＞Se.Ca,Mg,K and Fe were abundant in this herb.Most elements varied over a wide range depending on the different habitats.The mineral element data were evaluated by principal component analysis to reveal the distribution pattern of elements in tool Four principal components(KCa factor,Cu factor,Mg factor and Zn-Se factor)of plant elements were selected.The authors'study provided a new scientific foundation for further studies and general application of this Chinese herb.