Abstract: Heavy metal pollution has received increasing attention in recent
years mainly because of the public awareness of environmental issues. In this
study we have evaluated the effect of cadmium (Cd) on enzymes activity,
substrate utilization pattern and diversity of microbial communities in soil
spiked with 0, 20, 40, 60, 80, and 100 mg/kg Cd, during 60 d of incubation at
25°C. Enzyme activities determined at 0, 15, 30, 45, and 60 d after heavy
metal application (DAA) showed marked declines for various Cd treatments, and
up to 60 DAA, 100 mg/kg Cd resulted in 50.1%, 47.4%, and 39.8% decreases in
soil urease, acid phosphatase and dehydrogenase activities, respectively to
control. At 60 DAA, substrate utilization pattern of soil microbial communities
determined by inoculating Biolog ECO plates indicated that Cd addition had
markedly inhibited the functional activity of soil microbial communities and
multivariate analysis of sole carbon source utilization showed significantly
different utilization patterns for 80 and 100 mg/kg Cd treatments. The
structural diversity of soil microbial communities assessed by PCR-DGGE method
at 60 DAA, illustrated that DGGE patterns in soil simplified with increasing Cd
concentration, and clustering of DGGE profiles for various Cd treatments
revealed that they had more than 50% difference with that of control.
