Directorate of Weed Science Research

India

Directorate of Weed Science Research

India

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Yadav U.,Robertson College, Jabalpur | Choudhury P.P.,Directorate of Weed Science Research
Letters in Applied Microbiology | Year: 2014

Sulfosulphuron-degrading fungus was isolated by enrichment technique from the sulfosulphuron-contaminated soil of wheat rhizosphere. To assess the biodegradation potential of isolated Trichoderma sp., minimal potato dextrose agar broth with different levels of sulfosulphuron (up to 2 g l-1) was evaluated in the growth and biotransformation experiments. ESI LC-MS/MS analysis revealed the presence of degradation products 2-amino-4,6-dimethoxypyrimidine (I) and 2-ethylsulfonyl imidazo{1,2-a} pyridine-3-sulfonamide-2-ethylsulfonyl imidazo{1,2-a} pyridine-3-sulfonamide (II) indicating the cleavage of the urea bridge and the presence of the by-product N-(4,6-dimethoxypyrimidin-2-yl)urea (III) indicating the degradation of sulfonylamide linkage. Two other metabolites, N-(4,6-dimethoxypyrimidin-2-yl)-N'-hydroxyurea (IV) and N, N'-bis(4,6-dimethoxypyrimidin-2-yl)urea (V), were also identified. From the previous reports, it was found that the degradation of sulfonyl urea herbicides took place through the chemical degradation of the sulfonylurea bridge followed by microbial degradation. During this investigation, Trichoderma sp. grew well with and degraded sulfosulphuron via both the decarboxylation on the sulphonyl urea bridge and the hydrolytic cleavage of the sulfonylamide linkage as demonstrated by the formation of metabolites. Trichoderma is nonphytopathogenic in nature, and some species of it restrict the growth of soil-dwelling phytopathogens. Therefore, it is a promising candidate for the decontamination of soil from sulfosulphuron residues. Significance and Impact of the Study: The degradation of sulfosulphuron by any individual fungus is being reported for the first time. Trichoderma sp. isolated from wheat-rhizospheric soil could survive in minimal broth rich in sulfosulphuron. Previous reports have described the complete degradation of any sulfonyl urea herbicides by micro-organisms only after the pH-dependent chemical hydrolysis of the sulfonyl urea bridge of the herbicide. This study demonstrates the novel result that the Trichoderma sp. utilized the sulfosulphuron as a sole carbon source and degraded it by cleaving sulfonyl urea bridge and sulfonylamide linkage. Thus, the application of Trichoderma sp., which is nonphytopathogenic, has the potential to decontaminate agricultural soil from sulfosulphuron load. © 2014 The Society for Applied Microbiology.


Sondhia S.,Directorate of Weed Science Research | Waseem U.,Mata Gujri Girls College | Varma R.K.,Jawaharlal Agricultural University
Chemosphere | Year: 2013

Owing to reported phytotoxicity of some sulfonylurea class of herbicides in number of sensitive crops and higher persistence in soil, present study was conducted to isolate and identify pyrazosulfuron-ethyl degrading fungi from soil of rice field. Penicillium chrysogenum and Aspergillus niger, were isolated and identified from rhizospere soil of rice field, as potent pyrazosulfuron-ethyl degrading fungi. Degradation of pyrazosulfuron-ethyl by P. chrysogenum and A. niger, yielded transformation products/metabolites which were identified and characterized by LC/MS/MS. The rate of dissipation of pyrazosulfuron-ethyl was found higher in soil of rice field and soil inoculated with P. chrysogenum. This showed important route of degradation of pyrazosulfuron-ethyl by microbes apart from chemical degradation. © 2013 Elsevier Ltd.


Sondhia S.,Directorate of Weed Science Research
Toxicological and Environmental Chemistry | Year: 2013

Herbicides applied to vegetables play an important role in higher production of vegetables due to effective and timely control of weeds but at the same time herbicides residue may produce numerous environmental problems. The aim of this study was to determine whether application of herbicide for control of annual weeds in vegetable growing areas at recommended levels resulted in residues at the time of harvest. Thus, terminal residues of pendimethalin in vegetables such as tomato, cauliflower, and radishes were studies under field conditions. Pendimethalin was applied as pre-emergence herbicides at 1 kg a.i. ha-1 to tomato, cauliflower, and radish crops. Soil and vegetables samples were collected from pendimethalin-treated plots at maturity to determine harvest time residues of pendimethalin. At harvest, 0.008, 0.001, and 0.014 μg/g residues of pendimethalin were found in tomato, cauliflower, and radishes, respectively. © 2013 Copyright Taylor and Francis Group, LLC.


Chandra N.,Veterinary Science University of Madhya Pradesh | Jain N.K.,Veterinary Science University of Madhya Pradesh | Sondhia S.,Directorate of Weed Science Research | Srivastava A.B.,Veterinary Science University of Madhya Pradesh
Bulletin of Environmental Contamination and Toxicology | Year: 2013

Deltamethrin (DM) is a broad-spectrum insecticide mainly used to protect crops, fruit and vegetables from pests such as mites, ants, weevils and beetles. Birds, animals and human beings living in same ecosystem are directly or indirectly at the risk of exposure to this insecticide leading to substantial decrease in growth. Thus we studied DM induced toxicity and ameliorative effects of alpha-tocopherol in broiler birds. DM was estimated in liver, breast and leg muscles of chickens feeding with only DM or DM with alpha-tocopherol daily for 42 days. Birds exposed to DM showed a dose dependent decrease in body weight on 5th, 6th and 7th weeks as compared to controls, and alpha-tocopherol partially restored the reduction in body weight. DM residue was found higher in liver as compared to breast and leg muscles. © 2013 Springer Science+Business Media New York.


Sondhia S.,Directorate of Weed Science Research | Khare R.R.,Jawaharlal Nehru Agricultural University
Environmental Monitoring and Assessment | Year: 2014

The ability of herbicides to be adsorbed by the soil and sediment and their tendency to be desorbed are some of the most important factors affecting soil and water contamination. Therefore, a sorption study was conducted to evaluate the adsorption of cyhalofop-butyl, butyl (2R)-2-[4-(4-cyano-2-fluorophenoxy) phenoxy] propanoate, in the sandy clay loam and clayey soils using a batch equilibrium method. The adsorption of cyhalofop-butyl was found positively related with the clay and organic carbon content. Freundlich constants (Kf) of cyhalofop-butyl in the clayey and sandy clay loam were found to be 13.39 and 2.21, respectively. Sorption coefficients (Koc) and distribution coefficients (Kd) were found to be 265.38 and 2,092.79, and 1.38 and 11.48, for sandy clay loam and clayey soils, respectively. The adsorption isotherm suggested a relatively higher affinity of cyhalofop-butyl to the adsorption sites at low equilibrium concentrations. The low value of the soil organic carbon partition coefficient (Koc) of cyhalofop-butyl in the sandy loam soil suggested its weaker adsorption in soil and thus increased its risk of mobility into water sources; hence, it should be used judiciously to prevent groundwater contamination © 2014 Springer International Publishing Switzerland.


Naidu V.S.G.R.,Directorate of Weed Science Research | Varshney J.G.,Directorate of Weed Science Research
Indian Journal of Agricultural Sciences | Year: 2011

An experiment was conducted in open top chambers (OTCs) during 2006-07 to study the carbon isotope discrimination (Δ13C) in wheat (Triticum aestivum L. emend Fiori & Paol.) leaves in response to elevated CO2, drought and competition by weeds (Phalaris minor, Chenopodium album and Avena fatua). It was observed that drought and weed competition had decreased the Δ whereas, elevated CO2 had increased the Δ and partially ameliorated the negative effects of drought and weeds on Δ. However, the Δ in wheat was not much influenced by stress but, by elevated CO2 when it was in association with P. minor suggesting the variability in Δ due to variation in competition by different weeds.


Bhattacharyya R.,Indian Agricultural Research Institute | Das T.K.,Indian Agricultural Research Institute | Pramanik P.,Indian Agricultural Research Institute | Ganeshan V.,Indian Agricultural Research Institute | And 2 more authors.
Nutrient Cycling in Agroecosystems | Year: 2013

We evaluated impacts of conservation agriculture (zero tillage, bed planting and residue retention) on changes in total soil N (TSN) and aggregate-associated N storage in a sandy loam soil of the Indo-Gangetic Plains. Cotton (Gossypium hirsutum) and wheat (Triticum aestivum) crops were grown during the first 3 years (2008-2011) and in the last year, maize (Zea mays) and wheat were cultivated. Results indicate that after 4 years the plots under zero tillage with bed planting (ZT-B) and zero tillage with flat planting (ZT-F) had 15 % higher TSN concentrations than conventional tillage and bed planting plots (CT-B) (0.63 g kg-1 soil) in the 0-5 cm soil layer. CT-B plots had lower soil bulk density that ZT plots in that layer. Plots under ZT-B (0.57 Mg ha-1) contained 20 % higher TSN stock in the 0-5 cm soil layer than CT-B plots (0.48 Mg ha-1). However, tillage had no impact on TSN concentration or stock in the sub-surface (5-15 and 15-30 cm) soil layers. Thus, in the 0-30 cm soil layer, ZT-B plots contained 6 and 5 % higher (P > 0.05) TSN stock compared with CT-B (2.15 Mg N ha-1) and CT-F (2.19 Mg N ha-1) plots respectively after 4 years. Plots that received cotton/maize + wheat residue (C/M + W RES) contained 16 % higher TSN concentration than plots with residues removed (N RES; 0.62 g kg-1 soil) in the surface (0-5 cm) layer. Plots with only cotton/maize residue (C/M RES) or only wheat residue (W RES) retention/incorporation had similar TSN concentrations and stocks in the subsurface layer. Plots under ZT-B also had more macroaggregates (0.25-8 mm) and greater mean weight diameter with lower silt + clay sized particles than CT-B plots in that layer. A greater proportion of large macroaggregates (2-8 mm) in the plots under C/M + W RES compared with N RES were observed. In the 5-15 cm soil layer ZT-B and C/M + W RES treated plots had more macroaggregates and greater mean weight diameter than CT-B and N RES treated plots, respectively. Because of the greater amount of large aggregates, plots under ZT-B and C/M + W RES had 49 and 35 % higher large macroaggregate-associated N stocks than CT-B (38 kg TSN ha-1) and N RES (40 kg TSN ha-1) plots, respectively, in the 0-5 cm soil layer, although aggregates had similar TSN concentrations in all plots. Both tillage and residue retention had greater effects on aggregate-associated N stocks in the 5-15 cm layers. In addition to N content within large macroaggregates, small macroaggregate-associated N contents were also positively affected by ZT-B and C/M + W RES. Tillage and residue retention interaction effects were not significant for all parameters. Thus, the adoption of ZT in permanent beds with crop residue addition is a better management option for improvement of soil N (and thus possibly a reduced dose of fertilizer N can be adopted in the long run), as the management practice has the potential to improve soil aggregation with greater accumulation of TSN within macroaggregates, and this trend would likely have additive effects with advancing years of the same management practices in this region. © 2013 Springer Science+Business Media Dordrecht.


Sharma S.,Directorate of Weed Science Research | Banerjee K.,National Research Center for Grape | Choudhury P.P.,Directorate of Weed Science Research
FEMS Microbiology Letters | Year: 2012

Chlorimuron-ethyl, ethyl-2-[[[[(4-methoxy-6-chloro-pyrimidin-2-yl)amino]carbonyl]amino] sulfonyl]benzoate, is used as a pre- and postemergence herbicide for the control of important broadleaved weeds in soybean and maize. Due to its phytotoxicity to rotation crops, concerns regarding chlorimuron contamination of soil and water have been raised. Although it is degraded in the agricultural environment primarily via pH- and temperature-dependent chemical hydrolysis, microbial transformation also has an important role. Fungi such as Fusarium and Alternaria are unable to survive in artificial media containing chlorimuron-ethyl at 25 mg L-1. However, Aspergillus niger survived in minimal broth containing chlorimuron at 2 mg mL-1. Aspergillus niger degraded the herbicide to harvest energy through two major routes of degradation. One route involves the cleavage of the sulfonylurea bridge, resulting in the formation of two major metabolites, namely ethyl-2-aminosulfonylbenzoate (I) and 4-methoxy-6-chloro-2-amino-pyrimidine (II). The other route is the cleavage of sulfonylamide linkage, which generates the metabolite N-(4-methoxy-6-chloropyrimidin-2-yl) urea (III). Two other metabolites, saccharin (IV) and N-methyl saccharin (V), formed from metabolite II, were also identified. A metabolic pathway for the degradation of chlorimuron-ethyl by A. niger has been proposed. © 2012 Federation of European Microbiological Societies.


Sondhia S.,Directorate of Weed Science Research
Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes | Year: 2013

Dissipation of pendimethalin in the soil of field peas (Pisum sativum L.) at 0 to 110 days, and terminal residues in green and mature pea were studied under field conditions. Pendimethalin was applied as pre-emergence herbicide at 750, to 185 g a.i. ha-1 in winter, in field peas. Dissipation of pendimethalin in the soil at 0 to 110 days followed first-order kinetics showing a half-life of 19.83 days averaged over all doses. Low pendimethalin residues were found in mature pea grain (0.004, 0.003, <0.001 μg g-1), and straw (0.007, 0.002, <0.001 μg g-1) at 750, 350 and 185 g a.i. ha-1 treatments, respectively. The study indicated that residues of pendimethalin in green and mature pea were within the prescribed MRL limits. © 2013 Taylor and Francis Group, LLC.


Naidu V.S.G.R.,Directorate of Weed Science Research
Indian Journal of Agricultural Sciences | Year: 2013

An experiment was conducted in open top chambers (OTCs) to study the growth, water-use efficiency and carbon isotope discrimination (δ13C) in Parthenium hysterophorus in response to elevated CO2. Parthenium plants were grown in OTCs maintained at ambient (370±20 ppm) and elevated (550±30) CO2 levels as well as under open field conditions. Water-use efficiency (WUE) was determined by gravimetric method. The carbon isotope discrimination (δ13C) was determined by Isotope Ratio Mass Spectrometry (IRMS). The CO2 enrichment enhanced both the above and below ground biomass in Parthenium. Water-use efficiency (WUE) and Carbon isotope discrimination (δ13C) were higher in plants grown under elevated CO 2 compared to plants under ambient CO2 conditions. The growth stimulation and increased water-use efficiency in Parthenium indicates that this weed could become more aggressive in future if the atmospheric CO 2 continue to rise coupled with the rise in temperature.

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