Abstract: By using random amplified polymorphic DNA (RAPD) technique, the DNA polymorphism of genome in Arabidopsis thaliana seedlings leaves under Cd stress was studied, and, in combining with leaf morphological and physiological indices, the sensitive biomarkers indicative of Cd stress were chosen. After treated with 0.125-3.0 mg Cd·L^-1 for 21 days, the soluble protein content in A. thaliana seedlings leaves had an inverted U-shape increase with increasing Cd concentration, but no significant changes were observed in leaf fresh weight and chlorophyll content. Of the 12 decamer oligonucleotide primers tested, only 5 gave specific and stable results. In the control, 44 bands of the RAPD fingerprints from the leaves were easily distinguished. The changes in the RAPD fingerprints under Cd stress included the variation of band intensity, loss of normal bands, and appearance of new bands, in comparison with the control. In addition, the changes were dose-dependent. The above results showed that the genomic template stability was significantly affected by Cd stress, and the DNA polymorphism was sensitive to Cd stress. Thereby, the DNA polymorphism detected by RAPD technique could be used as a potential biomarker assay for the detection of Cd pollution and its related biological effects.

Key words: Freshwater ecosystem, Ecosystem service, Evaluation index system