Abstract:
The activity of three soil enzymes (ureases, peroxidases and polyphenol oxidases) and the corresponding kinetic characteristics (
Vmax,
Vmax/
Km and
Km) were studied by comparing four regenerated plantations (
Cunninghamia lanceolata plantation,
Liriodendron chinense plantation,
Pinus massoniana plantation,
Alnus-Liriodendron mixed plantation) with the local natural secondary forests in subtropical zone of Dagang Mountains of Jiangxi Province.The results showed that:1) the enzyme activity,
Vmax and
Vmax/
Km of soil ureases, peroxidases and polyphenol oxidases of the four different plantations decreased with the increase of soil depth;2) comparing with the natural secondary forests, the activity of ureases, peroxidases and polyphenol oxidases of
C.lanceolata plantation decreased by 35%, 4% and 58% respectively in the depth of 0-0.2 m, while
Vmax and
Vmax/
Km of soil ureases decreased by 46% and 47%;3) the activity of other soil enzymes had the same tendency in this plantation;4) and the soil enzyme activity and kinetic characteristics in the
L.chinense plantation decreased too.In the soil depth of 0 (-) 0.2 m and 0.2 (-) 0.4 m in
P.massoniana plantation, the activity of ureases decreased by 54% and 62% respectively, while the peroxidases both increased by 23%, and polyphenol oxidases decreased by 28% and 42% respectively.
Km of peroxidases decreased by 44% and 48%, while
Vmax/
Km increased by 58% and 92% respectively.All the kinetic parameters of soil ureases decreased evidently, while polyphenol oxidases increased;5) the activity of soil ureases and polyphenol oxidases in the depth of 0 (-) 0.2 m of the
Alnus-Liriodendron mixed forests decreased by 38% and 9%, and
Vmax/
Km of ureases, peroxidases and polyphenol oxidases decreased by 7%, 38% and 54% respectively, but the activity of peroxidases showed no evident changes.