[Effects of temperature on soil organic carbon mineralization rate and enzyme kinetic para-meters in temperate and subtropical forests.]

We examined the effects of temperature on SOC mineralization rate (C _min ) and enzyme kinetic parameters in soils of two different latitudinal forests, i.e., broad-leaved Korean pine forest in Changbai Mountain at higher latitude and evergreen broad-leaved forest in Dinghu Mountain at lower latitude. The results showed that the soil C _min increased with temperature, and the C _min and Q10(C _min ) of the Changbai Mountain forest soil were higher than those of the Dinghu Mountain forest soil. The maximal rates of velocity (V _max ) and the half-saturation constant (K _m ) of the Changbai Mountain forest soil were higher relative to the Dinghu Mountain soil for both soil β-glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG), but being opposite for catalytic efficiency (V _max /K _m ). Both V _max and V _max /K _m of βG and NAG increased with the increase of incubation temperature, while K _m decreased, i.e., the affinity of enzymes to the substrate were increased. Inconsistent with the soil Q10 (C _min ), Q10(V _max ) and Q _{10(K m )} of the soil βG were higher in Dinghu Mountain forest soil than those in the Changbai Mountain forest soil. The mechanisms underlying the effects of temperate variation on C _min and the enzyme kinetic parameters were different, and thus the temperature sensitivity of C _min and enzyme kinetic parameters should be considered differentially in the models of soil biochemical process.