关键词: 土壤胞外酶, 潜在碳矿化速率, 季节动态, 森林类型, 地被植物

Abstract:

In order to explore spatiotemporal dynamics of soil extracellular enzyme activity (EEA) and its influence on potential mineralization rate of soil organic carbon (SOC) of the Daxing’an Mountain range, soil samples of three forests (Pinus sylvestris forest; Birch forest; Larch pine forest) and three ground cover plants in Larch forest (Grass; Ledum; Moss) were collected from Daxing’an Mountain range in summer and winter. Activities of six enzymes including carbon- (C) (β-1,4-glucosidase, β-1,4-xylosidase, β-D-cellobiohydrolase), nitrogen- (N) (N-acetyl-β-glucosaminidase, leucine aminopeptidase) and phosphorus- (P) (acid phosphatase) acquisition, potential mineralization rate of SOC and main environmental factors were analyzed and potential driving mechanisms were explored. Results showed that Both Pinus sylvestris forest and Birch forest exhibited significant higher activities of enzyme C, N and P in summer, however, Larch forest showed contrary seasonal dynamic with soil EEA of moss soil significantly higher in winter. From summer to winter, soils of three forests and three ground cover plants all experienced reduced P vs. N limitation. Besides, soils of Pinus sylvestris forest and Birch forest both experienced increased C vs. nutrient limitation, however, Larch forest showed contrary seasonal dynamics with the existence of moss. In Pinus sylvestris forest and Larch forest, potential mineralization rate of SOC exhibited higher in winter while Birch forest showed contrary trend. Analysis showed that potential mineralization rate of SOC was influenced by enzyme C and enzyme N significantly, whereas little influenced by enzyme P. C vs. nutrient limitation had little correlation while P vs. N limitation had significant negative correlation with potential carbon mineralization rate.

Key words: soil extracellular enzyme, potential carbon mineralization rate, seasonal dynamics, forest types, ground cover plants