关键词: 重金属污染, 伴矿景天, 芹菜, 化学效应, 微生物效应

Abstract: The hierarchical and agglomerative analysis was used to achieve numerical classification of the forest vegetation in the Jiuzhaigou Nature Reserve. The results obtained from the analysis of different distance coefficients and different clustring strategies indicated that there were eight formations of the forest vegetation in the nature reserve. The results of classification showed that the dominant plants belonged to the type of temperate zone distribution,mainly composed by Pinaceae,Betulaceae and Fagaceae. Pinaceaewas predominant vegetation, while faber forest was the widest distributed forest in Jiuzhaigou.The forest vegetation in this area also showed distinclly vertical distribution. It could be divided into needle -leaved and broad-leaf mixed forest zone and sub-alpine needle leaved forest zone from the low to the top in Jiuzhaigou. Finally, four commonly used strategies were discussed and the group-average strategy was considered to be an ideal method for hierarchical and agglomerative clustering.

Key words: heavy metals contamination, Sedum plumbizincicola, Apium graceolens,  chemical effect, microbial effect.