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991.
Agrawal SB Rathore D Singh A 《Journal of environmental biology / Academy of Environmental Biology, India》2006,27(1):55-60
In a field experiment, the effect of enhanced UV-B radiation (simulating 20% ozone depletion at Allahabad, 20 degrees 47' N latitude) was studied on two cultivars of Vigna radiata L. with various levels of mineral nutrients (N and P). Study showed decrease in total biomass accumulation, harvest index, RSR and yield after exposure with enhanced level of UV-B. RGR and CGR also showed decline after exposure with UV-B. Application of recommended dose of mineral nutrients alleviated the deleterious effect of UV-B and increased plant dry matter vis a vis yield. Both cultivars showed sensitivity to UV-B but cultivar Malviya Janpriya was more responsive to UV-B than Malviya Jyoti. 相似文献
992.
This study examined the roles of arsenic translocation and reduction, and P distribution in arsenic detoxification of Pteris vittata L. (Chinese Brake fern), an arsenic hyperaccumulator and Pteris ensiformis L. (Slender Brake fern), a non-arsenic hyperaccumulator. After growing in 20% Hoagland solution containing 0, 133 or 267 microM of sodium arsenate for 1, 5 or 10 d, the plants were separated into fronds, rhizomes, and roots. They were analyzed for biomass, and concentrations of arsenate (AsV), arsenite (AsIII) and phosphorus. Arsenic in the fronds of P. vittata was up to 20 times greater than that of P. ensiformis, yet showing no toxicity symptoms as did in P. ensiformis. While arsenic was concentrated primarily in the fronds of P. vittata as arsenite it was mainly concentrated in the roots of P. ensiformis as arsenate. Arsenic reduction in the plants took longer than 1-d. P. vittata maintained greater P in the roots while P. ensiformis in the fronds. The high arsenic tolerance of the hyperaccumulator P. vittata may be attributed to its ability to effectively reduce arsenate to arsenite in the fronds, translocate arsenic from the roots to fronds, and maintain a greater ratio of P/As in the roots. 相似文献
993.
ABSTRACT. Adequate and good-quality water supply for medium sized towns is costly when there are insufficient quantity and low quality of groundwater or surface water. In a central water supply system serving a number of towns, the economies of scale may permit a sufficient and good-quality supply at lesser rates. Such a system has the flexibility of supplying rural population through small service lines. The system may be an interbasin or intrabasin conveyance depending on the location of a suitable water source and the economics of the supply network. Seven cost elements are pertinent to the optimum or least-cost design of network consisting of pipelines and pumping stations. The relevant cost functions are based on the available data gathered from various sources. Water conveyance costs are calculated for various flow rates, pipeline diameters, flow variabilities, static heads, and interest rates, thus providing a measure of sensitivity of the conveyance cost to such variations. The economies of scale, the sensitivity of optimum unit conveyance costs, and variations in unit costs with change in cost functions are useful in making a feasibility study for a proposed conveyance system. 相似文献
994.
Samar Singh 《The Environmentalist》1985,5(1):31-37
Summary This theme paper introduces India's Action plan for Wildlife Conservation. The author describes the historic development of conservation management as related to India's remarkably diverse range of wildlife, and briefly describes the National Wildlife Action Plan.This paper was presented to the Centenary Seminar of the Bombay Natural History Society. 6–10 December, 1983. The theme of the seminar was Conservation in Developing Countries — Problems and Prospects. Complete copies of the paper and theNational Wildlife Action Plan are available directly from the author. 相似文献
995.
Vijay P. Singh 《Journal of the American Water Resources Association》1975,11(3):505-513
ABSTRACT: This study presents generalized and special forms of hydraulic solutions of surface water lag time, as conceptualized by Overton (1970), for the converging overland flow. It is shown that these solutions can be used to estimate lag time from physically measurable information on a given watershed. 相似文献
996.
In the present study, female Clarias batrachus were exposed to two sublethal concentrations of gamma-BHC (2 and 8 microg litre(-1)) and malathion (1 and 4 microl litre(-1)) for 4 weeks during different phases of their reproductive cycle. Impact of these pesticides on free fatty acids, monoglycerides, diglycerides, triglycerides, phospholipids, free and esterified cholesterol in the liver, plasma, ovary and muscle was assessed. During the pre-vitellogenic and regressed phases, they suppressed the levels of fatty acids and glycerides in the liver, but had no effect on their levels in the plasma, ovary and muscle. However, in the vitellogenic phase, fatty acids in the liver and plasma were increased, but were decreased in the ovary and muscle. Glycerides were also decreased in the studied tissues. In the post-vitellogenic phase, these pesticides increased the levels of fatty acids and glycerides in the liver and ovary, but decreased their levels in the plasma. Both pesticides decreased hepatic phospholipids in the pre-vitellogenic phase, while in the vitellogenic phase only gamma-BHC reduced its levels in the liver. These pesticides also restricted their mobilisation to the ovary. Cholesterol biosynthesis seemed unaffected, but the hydrolysis of esterified cholesterol to free cholesterol was adversely affected during the period of estrogen biosynthesis. 相似文献
997.
A pot experiment was carried out on a Typic ustipsamment to study the effect of Cd concentration on the yield of wheat (Triticum aestivum) and soybean (Glycine max). Cd levels taken were 1, 5, 10, 20, 40, 80, and 160 g g-1 of soil. Three different statistical procedures were employed to evaluate the phytotoxicity limits. The non-linear regression technique was found to be more effective in calculating C
0 (threshold concentration) and C
100 (toxic concentration) in comparison to Cate and Nelson (1971) and Beckett and Davis (1977) procedures. This technique was unaffected by the nature of the distribution of the data and did not require any initial value of concentration as a starting point. 相似文献
998.
999.
1000.
Microbial degradation of pendimethalin 总被引:7,自引:0,他引:7
Microbial degradation of pendimethalin (N-(1-Ethylpropyl)-3, 4-dimethyl-2, 6-dinitroaniline) in vitro was studied. Fusarium oxysporum and Paecilomyces varioti, two soil fungi, in culture media degraded pendimethalin to two metabolites namely N-(1-Ethylpropyl)-3, 4-dimethyl-2-nitrobenzene-1, 6-diamine (II) and 3,4-Dimethyl-2, 6-dinitroaniline (IV). Rhizoctonia bataticola, another soil fungus, decomposed pendimethalin yielding only the latter metabolite (IV). Fungal decomposition of pendimethalin involved nitro reduction and dealkylation. 相似文献