关键词: 阔叶纯林, 水源涵养, 土壤物理性质, 养分, 微生物, 酶活性

Abstract: Using semiquantitative reverse transcriptionpolymerase chain reaction (RT-PCR), the effects of cadmium (Cd) stress on the mismatch repair and proliferating cell nuclear antigen gene expression of Arabidopsis thalianaseedlings were studied and linked to the morphological and physiological indices of A. thaliana seedlings, aimed to choose the biomarkers sensitive to Cd stress. The results indicated that under Cd stress, no significant changes were observed in leaf number and shoot fresh mass of A. thaliana eedlings. The total soluble protein content of the shoots increased significantly when exposed to 0.25 mg Cd·L^-1 (P<0.05) but decreased significantly at 0.5 and 1.0 mg Cd·L^-1 (P<0.05), while the chlorophyll content had a slight increase with increasing Cd concentration (P>0.05). Using 18S rRNA as the internal standard, the expression of PCNA1, PCNA2, MSH2, MSH3, MSH6 and MSH7 genes in shoots was significantly induced at 0.25 mg Cd·L^-1. When the Cd concentration increased to 1.0 mg·L^-1, the expression of the genes was still induced, except that MSH6 was persistently induced and MSH3 was repressed compared with the control, but the expression was lower than that at 0.5 mg·L^-1of Cd. The above results suggested that specific gene expression could serve as the potential and useful biomarker for the detection of genotoxic effects of Cd pollution on plants.

Key words: Pure broad-leaved stand, Water conservation, Soil physical property, Nutrient, Microorganism, Enzyme activity