Characteristics of Heavy Metals in Plants Growing on Cr Contaminated Area and Cr-Tolerant Plants Screening

The research focused on heavy metal concentrations of soil and plants in Wenzhou’s tanning zone in Zhejiang Province of East China and relationship with soil pollution. The available plant germplasm resources for Cr contaminated soil restoration were initially definited. Twenty-five species belonging to 13 families were found in the polluted area, including 8 dominant species: Cynodon dactylon (L.) Pers., Chenopodium glaucum Linn., Ageratum conyzoides Linn., Malachium aquaticum (L.) Fries, Eleusine indica (Linn.) Gaertn., Rorippa indica (Linn.) Hiern, Amaranthus retroflexus Linn. and Oligostachyum lubricum (Wen) Keng f. The investigation showed that Cynodon dactylon (Linn) Pers., Chenopodium glaucum, Eleusine indica (Linn) Gaertn, Rorippa montana (Linn) Hiern, Amaranthus retroflexus Linn. were the adaptive pioneer species for soil ecological restoration. Cr concentrations in the aboveground were 110.26-774.05 mg·kg-1, and the average value was 280.95 mg·kg-1;concentrations in roots were 774.05-2 334.56 mg·kg-1, the average value was 1 229.75 mg·kg-1. Cr concentrations in the aboveground and root of Cynodon dactylon were the highest, 774.05 mg·kg-1 and 2 334.56 mg·kg-1, respectively. According to correlation analysis, the heavy metal content in aboveground plants and the roots had weak correlation with the content in soil. The result of regressive analysis indicated that the root content and bioaccmulation coefficients of Cr was both closely associated with the aboveground plants. The root bioaccmulation coefficients were enhanced with the increased aboveground plants.