排序方式: 共有16条查询结果,搜索用时 234 毫秒
11.
Litter decomposition and nutrient release in relation to atmospheric deposition of S and N in a dry tropical region 总被引:1,自引:0,他引:1
Temporal and spatial variations in litterfall, leaf litter decomposition and nutrient release were quantified along an air pollution gradient around an industrial area in a dry tropical region of India. Significant differences were found in litterfall between the sites. Litter decomposition rates also significantly varied among the study sites. Litter decomposition was faster at sites away from the industrial region with coal-fired power plants. The concentrations of N and P increased, whereas that of Ca and SO4-S decreased in decomposing litter over time. The nutrient release pattern was also modified by atmospheric deposition. Concentrations of SO2 and NO2 were negatively correlated with relative mass loss. Turnover time of nutrients, except SO4-S in decomposing litter was maximal at the site receiving highest atmospheric depositions. The study documents that industrial emissions significantly modified nutrient cycling in adjacent terrestrial ecosystems. 相似文献
12.
Adeeb Fatima Aditya Abha Singh Madhoolika Agrawal 《Archives of Agronomy and Soil Science》2018,64(12):1768-1776
Tropospheric ozone (O3) is considered harmful to agriculture production and soil community. Wheat cultivars HD 2987 (O3 sensitive) and Kharchiya 65 (O3 tolerant) were grown under ambient and elevated (ambient + 30 ppb) levels of O3 (EO) using open top chambers, and microbial biomass and enzymatic activities were investigated in soil rhizosphere. Elevated O3 declined soil enzymatic activities related to carbon cycling viz. β-glucosidase, cellobiohydrolase, cellulase and amylase more in sensitive cultivar compared to tolerant. Enzymatic activities linked to nitrogen cycling like N-acetyl-glucosaminidase and urease decreased while protease and glycine aminopeptidase increased. Microbial biomass carbon and nitrogen declined more in sensitive cultivar by 11.1 and 21.2%, respectively. Root biomass reduced in wheat cultivars with an increase of their phenolics contents by 34.3 and 10.2% in HD 2987 and Kharchiya 65, respectively at 60 days after germination. Non-significant changes were observed in soil organic carbon and total nitrogen in both the cultivars. Redundancy analysis suggested that soil enzymatic activities were predominantly affected by O3 induced changes in microbial biomass carbon and root biomass. Study also showed that rhizosphere of sensitive cultivar HD 2987 was affected more under EO as compared to tolerant Kharchiya 65. 相似文献
13.
Nutritional deficiency disease in an Indian major carp, Cirrhina mrigala Hamilton, due to avitaminosis C during early growth 总被引:1,自引:0,他引:1
Abstract. Experiments with a purified vitamin test diet on newly hatched Cirrhina mrigala Hamilton, a major carp of great piscicultural importance, are reported. Experimentally induced vitamin C deficiency for 330 days was followed by recovery treatment for 30 days. Retarded growth and greater mortality accompanied by structural deformities such as lordosis and scoliosis, increasing with prolonged deficiency, were recorded. Haematological and haematopoietic studies revealed hypochromic macrocytic anaemia accompanied by anisocytosis. Correlated studies on erythropoiesis revealed increased reticulocytes and an overall decrease in small lymphoid haemoblasts. Total and differential leucocyte counts revealed leucopenia and thrombopenia accompanied by an increase in neutrophils and eosinophils. Recovery treatment halted and in some cases even compensated these pathophysio-logical changes to some extent. 相似文献
14.
Abstract. Morphological, behavioural and haematological changes in Channa punctatus caused by infection with the digenean Isoparorchis hypselobagri are reported. Morphological changes include partial necrosis of fin tissue, scale loss (particularly along the opercula and caudal peduncle) and loss of pigmentation, together with considerable damage to the viscera, especially the gonads, and the abdominal muscles. Behavioural changes include partial or complete loss of equilibrium, irritability and convulsions. Haematological changes observed were a significant decrease in haemoglobin and haematocrit values resulting in hypochromicmacrocytic and normochromicnormocytic anaemia together with an increase in total leucocyte number. Significant decreases in blood glucose level and liver glycogen content were also observed. Some of the changes could be partially compensated by providing a bigger food ration. Compensatory effects were observed for haemoglobin and haematocrit values and leucocyte number. However, an increase in diet could not arrest the significant decrease in blood glucose level and liver glycogen content. The possible effects of parasitism on the utilization and productivity of C. punctatus are discussed. 相似文献
15.
Poonam Singh Madhoolika Agrawal Shashi Bhushan Agrawal 《Water, air, and soil pollution》2011,214(1-4):435-450
The effects of ambient O3 at two different levels of nitrogen, phosphorus, and potassium, (recommended and 1.5 times the recommended NPK) on three tropical varieties of mustard (Brassica campestris L. var. Kranti, Aashirwad and Vardan) were explored to unravel the mechanism of protection under higher NPK level at a rural experimental site using open top chambers. Ambient O3 concentrations ranged from 27.7 to 59.04 ppb. Lipid peroxidation, antioxidative enzymes, and metabolites were higher, whereas photosynthetic pigments and protein were lower in all the varieties of mustard grown in non-filtered chambers than in filtered chambers. The magnitude of response varied with varieties, NPK levels and ages. Vardan showed a maximum stimulation in the antioxidative defense system, thus efficient scavenging of ROS produced by O3 and consequently conferred greater tolerance in terms of least reductions in pigments and protein as compared to Kranti and Aashirwad. The antioxidant defense system was not stimulated in response to 1.5 times the recommended NPK, but higher levels of pigments and protein were maintained compared to the recommended NPK under ambient O3 levels. 相似文献
16.
Coal mining adversely affects soil quality around opencast mines. Therefore, a study was conducted in 2010 and 2011 to assess seasonal and site-specific variations in physical, chemical, and biological properties of soil collected at different distances from mining areas in the Jharia coalfield, India. Throughout the year, the soil in sites near coal mines had a significantly higher bulk density, temperature, electrical conductivity, and sulfate and heavy metal contents and a significantly lower water-holding capacity, porosity, moisture content, pH, and total nitrogen and available phosphorus contents, compared with the soil collected far from the mines. However, biological properties were site-specific and seasonal. Soil microbial biomass carbon (MBC) and nitrogen (MBN), MBC/MBN, and soil respiration were the highest during the rainy season and the lowest in summer, with the minimum values in the soil near coal mines. A soil quality index revealed a significant effect of heavy metal content on soil biological properties in the coal mining areas. 相似文献