The research explored response of cellulase in Eisenia fetida in soils with Cd at different concentrations, as per artificial soil test. The results indicated that as Cd concentration increased, the activity of cellul...The research explored response of cellulase in Eisenia fetida in soils with Cd at different concentrations, as per artificial soil test. The results indicated that as Cd concentration increased, the activity of cellulase was decreasing in a short peri- od, which suggested that cellulase activity was inhibited to certain extent. As Cd concentration and the treatment period grew, the activities increased in varying de- grees. With Cd at a high concentrate, Cd had a kind of induction effects on cellu- lase activity in earthworms.展开更多
Earthworms, one of the most important macroinvertebrates in terrestrial ecosystems of temperate zones, exert important influ- ences on soil functions. A laboratory microcosm study was conducted to evaluate the influen...Earthworms, one of the most important macroinvertebrates in terrestrial ecosystems of temperate zones, exert important influ- ences on soil functions. A laboratory microcosm study was conducted to evaluate the influence of the earthworm Eisenia fetida on wheat straw decomposition and nutrient cycling in an agricultural soil in a reclaimed salinity area of the North China Plain. Each microcosm was simulated by thoroughly mixing wheat straw into the soil and incubated for 120 d with earthworms added at 3 different densities as treatments： control with no earthworms, regular density （RD） with two earthworms, and increased density （ID） with six earthworms. The results showed that there was no depletion of carbon and nitrogen pools in the presence of the earthworms. Basal soil respiration rates and metabolic quotient increased with the increase in earthworm density during the initial and middle part of the incubation period. In contrast, concentrations of microbial biomass carbon and microbial biomass quotient decreased in the presence of earthworms. Earthworm activity stimulated the transfer of microbial biomass carbon to dissolved organic carbon and could lead to a smaller, but more metabolically active microbial biomass. Concentrations of inorganic nitrogen and NO^-N increased significantly with the increase in earthworm density at the end of the incubation （P ~ 0.05）, resulting in a large pool of inorganic nitrogen available for plant uptake. Cumulative net nitrogen mineralization rates were three times higher in the ID treatment than the RD treatment.展开更多
基金Key Scientific Program of Scihuan Provincial Department of Education."Research on Soil Heavy Metal Pollution Biological Track Examination and Soil Repaired by Earthworm"Phased Research Results~~
文摘The research explored response of cellulase in Eisenia fetida in soils with Cd at different concentrations, as per artificial soil test. The results indicated that as Cd concentration increased, the activity of cellulase was decreasing in a short peri- od, which suggested that cellulase activity was inhibited to certain extent. As Cd concentration and the treatment period grew, the activities increased in varying de- grees. With Cd at a high concentrate, Cd had a kind of induction effects on cellu- lase activity in earthworms.
基金the National Natural Science Foundation of China (No.31070454)the Program for Key Discipline of Ecology ofBeing City, China (No.XK10019440)
文摘Earthworms, one of the most important macroinvertebrates in terrestrial ecosystems of temperate zones, exert important influ- ences on soil functions. A laboratory microcosm study was conducted to evaluate the influence of the earthworm Eisenia fetida on wheat straw decomposition and nutrient cycling in an agricultural soil in a reclaimed salinity area of the North China Plain. Each microcosm was simulated by thoroughly mixing wheat straw into the soil and incubated for 120 d with earthworms added at 3 different densities as treatments： control with no earthworms, regular density （RD） with two earthworms, and increased density （ID） with six earthworms. The results showed that there was no depletion of carbon and nitrogen pools in the presence of the earthworms. Basal soil respiration rates and metabolic quotient increased with the increase in earthworm density during the initial and middle part of the incubation period. In contrast, concentrations of microbial biomass carbon and microbial biomass quotient decreased in the presence of earthworms. Earthworm activity stimulated the transfer of microbial biomass carbon to dissolved organic carbon and could lead to a smaller, but more metabolically active microbial biomass. Concentrations of inorganic nitrogen and NO^-N increased significantly with the increase in earthworm density at the end of the incubation （P ~ 0.05）, resulting in a large pool of inorganic nitrogen available for plant uptake. Cumulative net nitrogen mineralization rates were three times higher in the ID treatment than the RD treatment.
