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51.
S. U. KHAN 《European Journal of Soil Science》1973,24(2):244-248
The adsorption of diquat (1,1′-ethylene-2,2′-bipyridylium dibromide) and paraquat (1, 1′-dimethyl-4,4′-dipyridylium dichloride) by an organo-clay complex has been investigated. Paraquat was adsorbed by the organo-clay complex in greater amounts than was diquat. Infrared studies suggest the formation of charge-transfer complexes between diquat or paraquat and the organo-clay complex. Organic matter upon interaction with clay may facilitate the adsorption of diquat and paraquat on clay minerals in soil. 相似文献
52.
阴离子对应用于红壤中的微生物量的镉毒害的影响 总被引:4,自引:0,他引:4
A laboratory incubation experiment was conducted to elucidat the effects of associated anions on toxicity of cadmium applied to microbial biomass in the red soil. Cadmium was applied at six different levels,i.e.,O(background),5,15,30,60 and 100μg g^-1 soil in the form of either cadmium acetate or cadmium chloride. Application of cadmium as cadmium acetate markedly reduced the soil microbial biomass carbon compared to cadmium applied as cadmium chlorde at all the tested levels.Similarly,organic carbon to biomass carbon ration in the soil was markedly increased by increasing the level of the cadmium in the soil as cadmium acetate,while the change wa much smaller in the case of cadmium chloride at the same cadmium levels.The results suggested that due consideration should be given to the source of cadmium while deciding the cadmium levles in experiments. 相似文献
53.
Mohammed Abu Ali KHAN Mohammed Anwar HOSSAIN Kenji HARA Kiyoshi OSATOMI Tadashi ISHIHARA Yukinori NOZAKI 《Fisheries Science》2003,69(6):1271-1280
54.
Abstract. The reproductive biology of a popular and abundant freshwater catfish, Mystus nemurus Cuvier & Valenciennes, was examined, including sex ratio, gonadosomatic index, ova diameter and fecundity. The numerical ratio of male to female was 1:1.06 and was not significantly different (P > 0.05). Mean female gonadosomatic indices (GSI) in April and September corresponding to north-east and south-west monsoons were significantly different (P < 0.05) from the dry season (May, June, July and August). Thus the apparent GSI maxima in April and September were indicative of peak spawning period. However, there were no significant differences (P > 0.05) in the fluctuation of the measure of GSI except for those in the dry months, which probably suggested the existence of a protracted breeding season. Mean male GSI in February and November were similarly significant (P < 0.05) to the dry season, although not statistically different (P > 0.05) from those of January, March, April, July, August, October and November. This was probably attributable to an extended breeding period with spawning peaks in February and November corresponding to early and late monsoons. The aseasonal reproduction is common in tropical fishes. GSI were positively correlated with rainfall and water level fluctuations. Fecundity varied from a minimum 6900 to a maximum 93510 in specimens with total lengths of 34.8cm and 45.0cm respectively. Fecundity was found to increase linearly with length and weight and was significantly different (P < 0.05) from them. 相似文献
55.
堆肥, 石灰和磷酸二铵对铜尾矿土壤重金属的植物有效性的影响 总被引:4,自引:0,他引:4
Soil samples from a historic copper mine tailing site at the Parys Mountain,North Wales (UK) were amended with green waste compost (GC),GC+30% sewage sludge (GCS),lime and diammonium phosphate (DAP),to determine the effect of amendments on DTPA-and Ca (NO3) 2-extractable metals in the mine tailing and on the phytoavailability of heavy metals by a lettuce (Lactuca sativa L.).Both compost were added at the rate of 10% by weight,lime was added as calcium carbonate equivalent (pH = 7) and DAP at a 2300 mg kg-1 soil level.The experiment was arranged in randomised complete design with three replicates in pots under control environment.Addition of lime resulted in the largest reduction in metal extractability with DTPA and Ca (NO3) 2 and phytoavailability of Cu,Fe and Zn while DAP was effective in lowering Pb extractability and phytoavailability.With exception of Zn,all other metals extracted decreased with time after amendment applications.The distribution of heavy metals between and within the four procedures of potentially bioavailable sequential extraction (PBASE) varied significantly (P < 0.001).Stronger relationships were noted between the metals extracted with PBASE SE1 and Cu,Pb (P < 0.01) and Fe (P < 0.001) in the lettuce.These results indicate that addition of lime is sufficient to restore the vegetative cover to a high metal mine waste while DAP is good for stabilizing Pb,but its detrimental role on plant growth and the risk associated with presence of N in DAP (through N leaching) may restrict its chances for remediation of contaminated sites. 相似文献
56.
玉米铬毒性研究:氧化损伤、渗透调节物质积累、抗氧化防御以及铬的吸收 总被引:1,自引:0,他引:1
Shakeel Ahmad ANJUM Umair ASHRAF Imran KHAN Mohsin TANVEER Muhammad SHAHID Abdul SHAKOOR WANG Longchang 《土壤圈》2017,27(2):262-273
Agricultural production systems are immensely exposed to different environmental stresses in which heavy metal stress receives serious concerns. This study was conducted to explore the deleterious effects of different chromium(Cr) stress levels, i.e., 0, 30, 6090, 120, and 150 μmol L-1, on two maize genotypes, Wandan 13 and Runnong 35. Both genotypes were evaluated by measuring their growth and yield characteristics, Cr accumulation in different plant tissues, alterations in osmolyte accumulation, generation o reactive oxygen species(ROS), and anti-oxidative enzyme activity to scavenge ROS. The results showed that Cr stress decreased the leaf area, cob formation, 100-grain weight, shoot fresh biomass, and yield formation, while Cr accumulation in different maize tissues was found in the order of roots leaves stem seeds in both genotypes. The increased Cr toxicity resulted in higher free proline soluble sugars and total phenolic contents, and lower soluble protein contents. However, enhanced lipid peroxidation was noticed in the forms of malondialdehyde, hydrogen peroxide(H2O2) and thiobarbituric acid reactive substance accumulation, and electrolyte leakage. The hyperactivity of superoxide dismutase, peroxidase, catalase, ascorbate peroxidase, especially glutathione peroxidase and glutathione reductase indicated that these anti-oxidative enzymes had a central role in protecting maize from Cr toxicity, especially for Wandan 13. Moreover, higher uptake and less translocation of Cr contents into the grains of Wandan 13 implied its importance as a potential candidate against soil Cr pollution. 相似文献
57.
Effects of red and blue LEDs on in vitro growth and microtuberization of potato single-node cuttings
Lili CHEN Xuzhang XUE Yadong YANG Fei CHEN Jie ZHAO Xiquan WANG Alam Tariful KHAN Yuegao HU 《农业科学与工程前沿(英文版)》2018,5(2):197
The objectives of this study were to investigate the effects of red and blue LEDs on in vitro growth and microtuberization of potato (Solanum tuberosum) single-node cuttings. Explants were incubated under 6 light treatments: 100% red LEDs (R), 75% red LEDs+ 25% blue LEDs (3RB), 50% red LEDs+ 50% blue LEDs (RB), 25% red LEDs+ 75% blue LEDs (R3B), 100% blue LEDs (B) and white LEDs (W). Most of the growth and physiological parameters were significantly higher in 3RB than W. Enhancement of leaf area and chlorophyll concentrations were obtained in B. Leaf stomata were elliptical with the lowest density in 3RB. However, those in W were round in shape, and those with the smallest size and the highest density were observed in R. Most of the characteristics of microtuberization were also improved in 3RB. The combined spectra of red and blue LEDs increased the number of large microtubers. The fresh weight of individual microtubers in R and W were increased, but not their number. These results suggest that, of the treatments assessed, 3RB is optimal for the in vitro growth of potato plantlets and the combination of red and blue LEDs is beneficial for microtuberization. 相似文献
58.
Crop performance on degraded soil needs special management practices to overcome soil quality limitations. In a 2-year(from summer 2006 to winter 2007–2008) field trial on a moderately degraded Alfisol in Swabi District(34°7′12′′N, 72°28′20′′E), Pakistan,the effects of three cropping patterns, cereal-cereal(CC), cereal-legume(CL), and cereal-cereal and legume intercrop(CLI), were tested in main plots under four fertilization treatments in sub-plots, including no fertilization(control), farmers' practice(FP, 60:45 kg ha~(-1) N:P_2O_5), recommended dose(RD, 120:90:60 kg ha~(-1) N:P_2O_5:K_2O), and integrated nutrient management(INM, 20 t ha~(-1) farmyard manure integrated with 50% N, 100% P, and K of recommended dose), using a split-plot randomized complete block design. The performance of CL was superior than CC in plant height, leaf area index(LAI), cob length, grain yield, biological yield, and grain protein(8%, 26%, 8%, 5%, 10%, and 8% increases, respectively), while CLI confirmed significant improvement only in LAI(25%) over CC. Response to nutrient inputs from all sources was in the order of INM RD FP control, and the maximum net economic return by INM(23% and 2.5 times higher than RD and FP, respectively) indicated severe deficiency of both macro-and micro-nutrients in the soil as well as degraded physical properties. Increases in soil organic matter, total N, total mineral N, available P and K, total porosity, and available water-holding capacity by 6%, 34%, 24%, 50%, 13%, 5%, and 7%, respectively, and decrease in soil bulk density by 4% after four crop seasons indicated optimistic changes in soil quality as a result of the combined effects of fertilization from organic and inorganic sources and legumes within crop rotation. This study suggests that keeping the soil covered under cereal-legume rotation crops all year round and treatment with INM(50% N from organic source and 50% from inorganic source) are the best management practice for sustained production on degraded Alfisols. 相似文献
59.
Pharmacokinetics and urinary excretion of sulphadimidine were determined in sheep and goats following a single intravenous injection (100 mg/kg). The disposition of the drug was described in terms of exponential expression: C p = Be -βt . Based on total (free and bound) sulphonamide level in plasma, pseudo-distribution equilibrium was rapidly attained and the half-life for elimination was 3.88 ± 0.64 h and 4.00 ± 0.34 h in sheep and goats, respectively. Body clearance, which is the sum of all clearance processes was 88 ± 19 and 55 ± 4 ml/kg/h in sheep and goats. Based on this study a satisfactory intravenous dosage regimen might consist of 100 and 60 mg sulphadimidine/kg body wt for sheep and goats and should be repeated at 12 h intervals. The influence of disease conditions on predicted plasma levels remain to be verified experimentally. Three-quarters of an intravenously injected dose of sulphadimidine was excreted in the urine of sheep and goats within 24 h of administration. The drug was mainly excreted as free amine while acetylated drug constituted 7 and 8% of total drug content in the urine of sheep and goats, respectively. 相似文献
60.
Residus d'atrazine el de ses metabolites après une utilisation prolongée De I'atrazine a été appliquée dans un champ cultivé en maïs (Zea mays L.) pendant 20 annees consecutives, a des doses allant de 1.40 a 2.24 kg/ha. L'analyse d'échantillons de sol prélevés 6 et 12 mois après la derniere application a révélé la presence de residus du produit et de ses analogues hydroxy monodealkyles. Les jeunes pousses et les racines de plantes d'avoine (Avena saliva L.) cultivees dans le champ contenaient de l'hydroxytriazine (2-hydroxy-4-éthylamino-6-isopropyl-amino-i-triazine) et l'un de ses analogues monodealkyles sous la forme conjuguée. De l'avoine et de la fléole (Phleum pralense L.), cultivees sur le sol traité, dans une chambre de culture, donnèrent des resultats analogues. Les resultats suggèrent que les applications d'atrazine répétées a long terme annuellement pour le désherbage du maïs conduisent a la persistance dans le sol de certains de ses produits de degradation, principalement des analogues hydroxylés, un an apres la derniere application d'herbicide. Il est concevable que de tels résidus puissent pénétrer dans les cultures vivrières implantées dans un sol traite a 1'atrazine, dans 1'année ou les annees qui suivent la cessation d'un traitement a long terme. 相似文献