文摘
Vanadium (V) is an essential trace element for certain biological enzymatic reactions but becomes toxic at higher concentrations. The impact of V at concentrations of 0??-00?mg/kg?V(V) spiked in soils on soil enzymatic activities, and microbial diversity was investigated in soybean pot experiments. The results from sequential extraction of soil V indicated increasing V mobilizable fractions with increase of soil V concentrations. The soil sulfatase activity decreased drastically from 2.35??-.55 to 0.30??-.88?μmol methylumbelliferon (MUB)/[h?g soil] with increasing soil V loading at different vegetative stages. Surprisingly, the activity of soil phenol oxidase increased from 0??-.73 to 3.74??-.61?μmol-span class="a-plus-plus emphasis type-small-caps">l-3,4-dihydroxyphenylalanine (DOPA)/[h?g soil] with increasing soil V concentrations at different vegetative stages probably due to oxidation stress caused by V in soils. These observations were not affected by the presence of soybean plants. In comparison, soil phosphatase, protease, and ?-glucosidase showed no significant reaction to V concentrations in soil. Both fungal and bacterial communities changed significantly at different levels of V treatments. Accordingly, V may pose a threat to some biologically mediated functions in soils even at low bioavailable amounts.