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161.
A ciliate protozoan, Tetrahymenapyriformis was exposed to three insecticides, dieldrin, dimethoate, and permethrin for 12 hr to study the uptake and bioconcentration potential. Ciliates concentrated 922, 3547, and 1056 gg g?1 dry wt. over an initial concentration of 1 gg mL?1 of dieldrin, dimethoate, and permethrin, respectively. The highest bioconcentration factor for three insecticides was 2095, 3547, and 1110, respectively. It is suggested that if levels in the environment reach 1 gg mL?1 the chief effects would be reduction of cell population, and accumulation of the toxicants by ciliates. Accumulation of insecticides by ciliates would permit the toxicants to enter aquatic food chains. Thus the compounds could exert toxic effects at higher trophic levels. 相似文献
162.
Mangal Deep Tuti Ramesh Singh Pal Dibakar Mahanta Brij Mohan Pandey Jaideep Kumar Bisht 《Communications in Soil Science and Plant Analysis》2020,51(7):948-962
ABSTRACTLack of crop diversification with suitable vegetable-based cropping system is a major constraint in limiting the productivity and sustainability of north-western Indian sub-Himalayas. To find out a sustainable vegetable-based cropping system in this region, a three year colocasia-based vegetable intensive experiment was conducted at Hawalbagh, Almora, India in a sandy clay loam soil under sub-temperate climatic conditions. Seven colocasia-based vegetable cropping systems along with rice–wheat system were compared under recommended package and practices. The system productivity in terms of colocasia equivalent yield was highest under colocasia–onion–frenchbean (52.38 Mg ha?1) system. Sustainable yield index was highest with colocasia–gardenpea–frenchbean system (0.86). After 3 years, total soil organic carbon (0–5%), available N (2–22%), P (–7% to 14%) and K (3–15%) concentrations were increased in all cropping systems except rice–wheat system, where negative balance of available P (7%) was observed over that of initial soil. Significantly higher soil microbial activity, soil carbohydrate, dehydrogenase, protease, acid and alkaline phosphatases activity were observed under colocasia–onion system. The results suggest that colocasia–onion–frenchbean system with higher productivity improves soil fertility and enhances enzymatic activities. 相似文献
163.
Developmentally specific expression of Rhizobium spp. genes involved in symbiotic N2 fixation is known to operate through cascade regulation of various nif and fix operons. Fusion constructs of lacZ under symbiotic promoters P1 (for nifHDK operon) and P2 (for fixABCX operon) of Rhizobium meliloti were mobilized into Rhizobium spp. (Cicer) strains Rcd301 and RCR13. The assays for -galactosidase activity to monitor the expression of lacZ under these promoters was performed in host backgrounds of Escherichia coli, R. meliloti, and Rhizobium spp. (Cicer). The enzyme assays indicated significant levels of expression from P1 and P2 promoters in chickpea rhizobia, specifically in symbiotic cells from nodules. However, as in R. meliloti, these promoters did not induce strong expression in free-living cells of Rhizobium spp. (Cicer). This indicates functional homology of R. meliloti promoters in rhizobium spp. (Cicer). Functional cross-reactivity of trans regulatory factors like NtrA, NtrC, and NifA between these rhizobia seems evident from the nodule-specific expression of P1 and P2 cis elements. 相似文献
164.
Effluents from low temperature carbonization, high temperature carbonization and producer gas plants in India have been found to contain heavy metals. The level of metals differ from plant to plant and is attributed to operational conditions of carbonization units and quality of coal used. Phenols and organic bases present in the effluent can form organometallic complexes with metal ions present. Such complexes are of environmental significance being toxic, mutagenic and teratogenic in nature. The present investigation showed that LTC wastewater forms complexes with Fe, Cu, and Co, however it does not form any complex with Mn and Zn. 相似文献
165.
J. Somasundaram R. Krishnasamy P. Savithri M. Vassanda Coumar V. Arun Kumar B. Satish Kumar 《Journal of plant nutrition》2016,39(11):1556-1569
Sewage sludge (SS), a highly heterogeneous semisolid fraction of sewage water (about 1% of the sewage water), contains various amounts of nitrogen (N) and phosphorus (P) as well as trace elements such as cadmium (Cd), lead (Pb), copper (Cu), nickel (Ni) and zinc (Zn) with extremely variable physical and chemical compositions. Application of SS improves soil properties, increases yield and simultaneously increases trace metal content in soil and plants. The difficulty in handling, transporting and applying SS and its adverse effect, especially trace metal content in soil and plant, can be overcome by SS–coir pith pelletization (SSCP) or mixing with sewage sledge–coir pith mixture (SSCM). A study was undertaken to evaluate the prepared SSCM and SSCP (1:1 ratio of SS and coir pith) along with SS on dry matter yield, trace metal content in soil and plant parts. The results showed that increased rates of application of SS or SSCM or SSCP increased the green and dry fodder yield of forage maize. Application of SS as either SSCM or SSCP at 1.2 and 2.4 g pot?1 significantly reduced the trace metal content diethylene triamine pentaacetic acid (DTPA extractable) in soil and plant parts (leaves steam and root) compared to SS application. Therefore, in order to reduce the bioavailability of trace metal in soil and its uptake by plant, application of SSCM or SSCP at 1.2 or 2.4 g pot?1 proved to be a better option than SS application. 相似文献
166.
An efficient method for the purification and characterization of nematicidal azadirachtins A,B, and H,using MPLC and ESIMS 总被引:2,自引:0,他引:2
Sharma V Walia S Kumar J Nair MG Parmar BS 《Journal of agricultural and food chemistry》2003,51(14):3966-3972
Azadirachtin A enriched concentrate containing 60% active ingredient (a.i.) was prepared from the methanolic extract of the de-fatted neem (Azadirachta indica A. Juss) seed kernels. Azadirachtins A, B, and H, the three major bioactive constituents of neem seed kernel, were purified from this methanolic concentrate by employing reverse phase medium-pressure liquid chromatography (MPLC), using methanol-water solvent system as an eluant. The three pure azadirachtin congeners thus obtained were characterized by their unique mass spectral fragmentation, using electrospray probe in positive ion mode (ESI). All three azadirachtins exhibited nematicidal and antifungal activities. Azadirachtin B was the most effective against the reniform nematode Rotylenchulus reniformis (EC(50) 96.6 ppm), followed by Azadirachtin A (119.1 ppm) and H (141.2 ppm). At 200-ppm concentration, the test compounds caused 50-65% mortality of Caenorhabditis elegans nematode. Azadirachtin H showed the highest activity against the phytophagous fungi Rhizoctonia solani (EC(50) 63.7 ppm) and Sclerotium rolfsii (EC(50) 43.9 ppm), followed by B and A. The isolation of pure azadirachtins A, B, and H directly by MPLC purification from its concentrate and their characterization by ESIMS are unique and less time-consuming. 相似文献
167.
Manoj Kumar Kuldeep Bauddh Manish Sainger Poonam Ahlawat Sainger 《Journal of plant nutrition》2015,38(2):260-276
To find effective alternatives to reduce the application of conventional urea (CU), a conventional biofertilizer (CB) preparation (charcoal mixed Azotobacter chroococcum and Bacillus subtilis) and the same biofertilizers entrapped in an organic matrix consisting of cow dung, rice bran, dried powder of neem leaves, and clay soil in 1:1:1:1 ratio and 25% (w/w) saresh (plant gum of Acacia sp.), named as super granules of biofertilizers (SGBF) were applied to cultivate wheat (Triticum aestivum L. cv. ‘WH-711’) in experimental plots. The results revealed that the efficacy of commercially available charcoal mixed biofertilizers could not prove as effective alternative to CU, whereas the same dose of biofertilizers entrapped in the organic matrix, SGBF, resulted in a significant increase in growth and productivity of wheat. It appears that SGBF prepared and applied in this study is an effective organic alternative to the urea for wheat cultivation in semi-arid subtropical agro-ecosystems. 相似文献
168.
169.
Inheritance of resistance to lindane in a laboratory-selected strain of Tribolium castaneum (Herbst)
Studies on the inheritance of resistance to lindane in a laboratory-selected strain of Tribolium castaneum, by making crosses between the resistant and a susceptible strain, showed that resistance in this strain is controlled by an autosomally inherited single gene which is incompletely dominant. 相似文献
170.
Anuj Kumar Pavla Ryparovà Bohumil Kasal Stergios Adamopoulos Petr Hajek 《Wood material science & engineering》2020,15(1):57-63
ABSTRACTBamboo scrimber is one of the most emerging structural materials for future building applications and it possesses properties comparable to other natural wood-based engineered materials such as glulam, laminated veneer lumber and cross-laminated timber. The goal of this work was to study the decay resistance of bamboo scrimber against white-rot (Trametes versicolor) and brown-rot fungi (Serpula lacrymans). Bamboo scrimber samples were incubated in petri dishes with the wood-decaying fungi and the weight loss after 12 weeks was measured. The surface morphology of fungal-degraded bamboo scrimber was evaluated using optical microscopy. Based on the percentage weight loss, bamboo scrimber could be classified as highly resistant against bio-deterioration by white and brown-rot fungi. 相似文献