Browsing by Author "Asha Sahu"

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Adsorption-desorption studies of cadmium in three different soil orders
(Technoscience Publications, 2014) Asha Sahu; S.K. Singh; Nisha Sahu; Bali Ram; M.C. Manna
Sorption isotherms have been widely used to assess the heavy metals retention characteristics of soil particles. Adsorption behaviour of cadmium (Cd) in soils is an important process which exerts a major influence on its uptake by plant roots. Desorption behaviour of the retained metals, however, usually differ from that of adsorption, leading to a lack of coincidence in the experimentally obtained adsorption and desorption isotherms. Three soils differing in physico-chemical properties (pH 5.7 to 8.2) and varied taxonomy (Typic Ustochrepts, Typic Rhodustalfs and Entic Chromusterts), were subjected to Cd treatment at various concentrations (0, 2, 4, 8, 15, 30, 45, 75 mg Cd/L). The Cd adsorbed by each soil was calculated as the difference between the amount of Cd present in the solution initially and that remaining after equilibration. Immediately after adsorption, desorption took place using successive dilution method with five consecutive desorption steps. Both, Cd adsorption and desorption data were described by Freundlich equation. The adsorption and desorption reactions, however, did not provide the same isotherms, indicating that hysteresis occurred in Cd adsorption-desorption process. Results indicated that the adsorption capacity of the soils for Cd increased with an increase in the pH or alkalinity of the soils. The rate of adsorption was, however, found to decrease with increased pH. But no specific trend was observed in case of desorption. All the three soils used in this study followed Freundlich adsorption isotherms. The adsorption data, in general, indicated that Cd was in a fixed form at higher pH levels. The Cd adsorption was in the order of Entic Chromusterts > Typic Ustochrepts > Typic Rhodustalfs.
Bioremediation of heavy metals from soil and aquatic environment: An overview of principles and criteria of fundamental processes
(MDPI, 2015) Ruchita Dixit; Wasiullah; Deepti Malaviya; Kuppusamy Pandiyan; Udai B. Singh; Asha Sahu; Renu Shukla; Bhanu P. Singh; Jai P. Rai; Pawan Kumar Sharma; Harshad Lade; Diby Paul
Heavy metals are natural constituents of the environment, but indiscriminate use for human purposes has altered their geochemical cycles and biochemical balance. This results in excess release of heavy metals such as cadmium, copper, lead, nickel, zinc etc. into natural resources like the soil and aquatic environments. Prolonged exposure and higher accumulation of such heavy metals can have deleterious health effects on human life and aquatic biota. The role of microorganisms and plants in biotransformation of heavy metals into nontoxic forms is well-documented, and understanding the molecular mechanism of metal accumulation has numerous biotechnological implications for bioremediation of metal-contaminated sites. In view of this, the present review investigates the abilities of microorganisms and plants in terms of tolerance and degradation of heavy metals. Also, advances in bioremediation technologies and strategies to explore these immense and valuable biological resources for bioremediation are discussed. An assessment of the current status of technology deployment and suggestions for future bioremediation research has also been included. Finally, there is a discussion of the genetic and molecular basis of metal tolerance in microbes, with special reference to the genomics of heavy metal accumulator plants and the identification of functional genes involved in tolerance and detoxification. © 2015 by the authors.
Can endophytic Arthrobotrys oligospora modulate accumulation of defence related biomolecules and induced systemic resistance in tomato (Lycopersicon esculentum Mill.) against root knot disease caused by Meloidogyne incognita
(2013) Udai B. Singh; Asha Sahu; Nisha Sahu; Bhanu P. Singh; R.K. Singh; Renu; Dhananjaya P. Singh; R.K. Jaiswal; B.K. Sarma; H.B. Singh; M.C. Manna; A. Subba Rao; S. Rajendra Prasad
The soil community is an often ignored part of research which links plant biodiversity and ecosystem functioning despite their influence on numerous functions such as decomposition and nutrient cycling. Few consistent patterns have been detected that link plant and soil community composition; however, it has not been studied in details. Arthrobotrys oligospora, a model predacious fungus for nematode trapping, beside biocontrol potential may modulate plant health and increase natural antioxidants in tomato fruit directly or indirectly. In the present study we have investigated the effects of nematode trapping fungus A. oligospora on induction and bioaccumulation of natural antioxidant and defence related biomolecules in tomato plants when challenged with Meloidogyne incognita causing root knot. Endophytic and rhizospheric isolates of A. oligospora were isolated from different parts of India and characterized under controlled laboratory conditions. The study describes the multifarious effects of endophytic and rhizospheric isolates of A. oligospora in green house and field conditions in tomato plants when inoculated individually or in combination. It was found that A. oligospora EAO-147 and RST-101 when applied individually or in combination significantly increased various attributes in plants. Among both the isolates, endophytic A. oligospora EAO-147 was found to be more potential in enhancing the defence related biomolecules, enzymes and exhibited biocontrol potentials against M. incognita. With application of A. oligospora, increase in nutritional quality of ripe tomato fruits (mineral nutrients and natural antioxidant properties) was also demonstrated first time. Results suggest that application of A. oligospora, particularly endophytic, not only helps in control of nematodes but also increase plant growth as well as enhances the nutritional value of tomato fruits. Thus, it proves to be an excellent biocontrol as well as plant growth promoting agent. © 2012 Elsevier B.V.
Co-inoculation of Dactylaria brochopaga and Monacrosporium eudermatum affects disease dynamics and biochemical responses in tomato (Lycopersicon esculentum Mill.) to enhance bio-protection against Meloidogyne incognita
(2012) Udai B. Singh; Asha Sahu; Nisha Sahu; R.K. Singh; Renu; Ratna Prabha; D.P. Singh; B.K. Sarma; M.C. Manna
The nematode trapping ability of nematophagous fungi Dactylaria brochopaga and Monacrosporium eudermatum to colonize tomato root and parasitize and kill root-knot nematode Meloidogyne incognita was evaluated, along with the capability of the fungi to induce the accumulation of defence-related biomolecules in tomato plants under the greenhouse and field conditions. Co-inoculation of D. brochopaga Dp-5 and M. eudermatum Mv-1 significantly reduced root-knot disease in tomato (89.63%) and increased the accumulation of total chlorophyll (125.34, 140.53 and 152.67 mg g -1 fresh wt.), total phenolic compounds (TPC) (37.40, 48.32 and 59.63 μg of gallic acid equivalent), and phenylalanine ammonia lyase (PAL) activity (58.45, 69.05 and 74.57 mM cinnamic acid h -1 g -1 fresh wt.) after 10, 20 and 30 days of inoculation, respectively, in the greenhouse. However, in the field experiments, the total chlorophyll content in leaves of M. incognita infected tomato plants co-inoculated with D. brochopaga Dp-5 and M. eudermatum Mv-1 (152.70 mg g -1 fresh wt.) was higher than the plants treated with D. brochopaga Dp-5 or M. eudermatum Mv-1 individually (130.87 and 144.73 mg g -1 fresh wt., respectively) and M. incognita treated plants (19.47 mg g -1 fresh wt.). TPC and PAL activity were found to be higher in tomato leaves co-inoculated with D. brochopaga Dp-5 and M. eudermatum Mv-1 (62.90 μg of gallic acid equivalent and 79.33 mM cinnamic acid h -1 g -1 fresh wt., respectively) than the plants treated with D. brochopaga Dp-5 or M. eudermatum Mv-1 individually, whereas in M. incognita inoculated and control plants, the induction of these two compounds was found to be very low after 30 days of inoculation. The results of this study showed that these fungi reduced root-knot disease and enhanced accumulation of defence related biomolecules in tomato plants and has potential to serve as a biocontrol agents against root-knot nematodes. © 2012 Elsevier Ltd.
Critical toxic concentration of cadmium in african marigold grown in typic ustochrept soil
(Technoscience Publications, 2017) Asha Sahu; Nisha Sahu
Heavy metals are potentially toxic to human life and the environment. In a greenhouse pot experiment, Typic Ustochrepts soil order (alluvial soil) with pH 5.7 was used. African marigold variety Pusa Narangi was used as a test crop. The soil was artificially spiked with different cadmium (Cd) levels (0, 5, 10, 25, 50 and 100 mg kg-1). Critical toxic concentrations of Cd resulting in 25 per cent reduction in dry matter yield were established for African marigold grown in alluvial soil. The corresponding values for non-inoculated, arbuscular mycorrhiza (Glomus moseae) and phosphorus solubilizing fungi (Aspergillus awamori) treated soils, respectively, were 28, 24 and 16 mg kg-1 Cd applied in soil; 12, 12 and 8 mg kg-1 AB-DTPA extractable Cd in soil; 6.4, 6.2 and 6 mg kg-1 Cd content in plant tissues.
Effect of organophosphorus pesticides on enzyme activities in alluvial soil (Typic Ustochrepts)
(Technoscience Publications, 2014) Nisha Sahu; P. Raha; Asha Sahu; Udai B. Singh
Acephate, dimethoate and phosphamidon are organophosphate pesticides with high toxicity and may significantly affect soil microbial activities. However, the magnitude of this effect is unclear yet. The potential harmful effect of these pesticides on soil enzyme activity was accessed in the soil collected under controlled laboratory conditions. We examined the effect of recommended (RD) and double the recommended doses (2RD) of these pesticides on the soil enzymatic activities. The incubation study was carried out at 60% of maximum water holding capacity of the soil sample at 2±2°C for a period of 42 days. Our results indicated that high acephate, dimethoate and phosphamidon doses significantly affect enzymatic activities in the soil. Our results provide the first evidence that acephate, dimethoate and phosphamidon differentially affected the soil microbial community through inhibiting fungal and bacterial populations.
Evaluation of biocontrol potential of Arthrobotrys oligospora against Meloidogyne graminicola and Rhizoctonia solani in Rice (Oryza sativa L.)
(2012) Udai B. Singh; Asha Sahu; R.K. Singh; Dhananjaya P. Singh; Kamlesh K. Meena; J.S. Srivastava; Renu; M.C. Manna
The nematode trapping and mycoparasitic potential of Arthrobotrys oligospora was tested in vitro against Meloidogyne graminicola and Rhizoctonia solani, respectively. Five isolates of A. oligospora were isolated from different locations of India. Diversity of the trapping structures is large and highly dependent on the environmental condition and nature of the fungus. In A. oligospora, a three-dimensional adhesive net (in response to nematode) and hyphal coils developed around the hyphae of R. solani. In vitro trap formation and predacity were tested against second-stage juveniles of M. graminicola (J 2) and the interactions between A. oligospora and R. solani were recorded. Under field conditions, we demonstrated the biocontrol potential of A. oligospora against R. solani causing sheath blight of rice (Oryza sativa) for the first time. All the isolates of A. oligospora parasitized and killed M. graminicola and R. solani. Application of A. oligospora, isolate VNS-1, in soil infested with M. graminicola and R. solani reduced the number of root knot by 57.58-62.02%, sheath blight incidence by 55.68-59.32% and lesion length by 54.91-66.66% under green house and miniplot (field) conditions. Applications of A. oligospora to the soil increased plant growth: shoot length by 56.4-68.8%, root length by 44.0-54.55%, fresh weight of shoot and root by 62.91-65.4% and 38.9-44.19%, respectively, as compared to the plants grown in nematode infested soil. © 2011 Elsevier Inc.
Nematophagous fungi: Catenaria anguillulae and Dactylaria brochopaga from seed galls as potential biocontrol agents of Anguina tritici and Meloidogyne graminicola in wheat (Triticum aestivum L.)
(2013) Udai B. Singh; Asha Sahu; Nisha Sahu; R.K. Singh; Renu; Dinesh K. Singh; Bhanu P. Singh; R.K. Jaiswal; Dhananjaya P. Singh; J.P. Rai; M.C. Manna; K.P. Singh; J.S. Srivastava; A. Subba Rao; S. Rajendra Prasad
During the course of our investigation on the selective isolation and in vitro pathogenicity tests of the nematode egg parasite and endoparasitic Catenaria anguillulae and the nematode-trapping fungus Dactylaria brochopaga against Anguina tritici, and Meloidogyne graminicola, the two biocontrol agents were also examined for their capabilities to colonize wheat seed gall and also to reduce the M. graminicola, and A. tritici in wheat (Triticum aestivum L.). Using seed galls as bait was found effective for isolating the soilborne natural colonizers of seed galls of wheat caused by A. tritici. Seed galls were found severely infested with cellulose decomposers as well as nematode trapping fungi i.e., Fusarium spp. ., Verticillium spp., Aspergillus spp., Penicillium spp. Arthrobotrys oligospora, Arthrobotrys superba, Arthrobotrys dactyloides, Arthrobotrys musiformis, D. brochopaga, Monacrosporium eudermatum, Stylopaga hadra, Paecilomyces spp., and C. anguillulae. Co-inoculation of D. brochopaga DBS-105, and C. anguillulae CAS101 significantly reduced the root knot and seed gall in wheat and increased the plant growth parameters including length, and dry weight of root and shoot as well as yield attributing characters like spike length; number of seed per spike, test weight etc. under greenhouse conditions as compared to pathogen challenged plants without any bioagents/chemical nematicide. These bioagents have the potential to enhance production of quality seeds of wheat being free from hazardous pesticides and thus, can further be developed into marketable formulations in order to promote eco-friendly and sustainable means of crop production. © 2013 Elsevier Inc.
Novel bio-filtration method for the removal of heavy metals from municipal solid waste
(Elsevier B.V., 2020) M.C. Manna; Asha Sahu; Nirmal De; J.K. Thakur; Asit Mandal; Sudeshna Bhattacharjya; Avijit Ghosh; Mohammad Mahmudur Rahman; Ravi Naidu; Udai Bhan Singh; Raja Dakhli; M.P. Sharma; Sukanya Misra
Fast urbanization, and agricultural escalation produce a lot of municipal solid wastes (MSW). There is need to recognize economically practical innovations to debase substantial metals to an innocuous state. The present investigation aimed to recognize proficient fungi and develop bio-filtration strategy utilizing them for expulsion of substantial heavy metals (HMs) from tainted MSW compost (MSWC). Six fungi were isolated from sewage sludge, namely, Trichoderma viride, Aspergillus heteromorphus, Rhizomucor pusillus, Aspergillus flavus, Aspergillus terreus, and Aspergillus awamori. Growths of all these fungi were highly susceptible to Cd at 5 ppm. Trichoderma viride, Aspergillus awamori, and Rhizomucor pusillus were highly susceptible to Cu at 50 ppm. Aspergillus flavus and Aspergillus heteromorphus could tolerate Cr below 50 ppm. The varying degree of HM tolerance by different fungi may be due to diverse strategies to dodge HM toxicity. Functional groups like amide (-NH2), hydroxyl (-OH), carboxylate anions (-COO), carbonyl groups (-CO), C-F and C-Br were responsible for bio-sorption of heavy metals by fungi through chelation with HMs. We found Trichoderma viride and Aspergillus flavus based bio-filters were capable to remove the highest amount of Pb (>40%) and Cd (>20%). Aspergillus heteromorphus based bio-filters was the most efficient to remove Cu and Cr from MSWC (∼20%). Trichoderma viride, Aspergillus heteromorphus, Rhizomucor pusillus and Aspergillus flavus based bio-filters were equally effective for elicitation of Zn (∼30%) and Ni (>30%) toxicity. Differential minimum inhibitory concentration, uptake of HMs, bio-sorption capacity of HMs by fungi resulted in unequal efficacy of fungal bio-filters. © 2020 Elsevier B.V.
Phytoextraction of cadmium by African marigold (Tagetes erecta L.) grown under cadmium contaminated soil inoculated with arbuscular mycorrhizal fungus, Glomus mosseae
(Inderscience Publishers, 2020) Asha Sahu; S.K. Singh; Nisha Sahu; M.C. Manna; A.K. Patra
The African marigold (Tagetes erecta L.) was grown in cadmium-stressed soil, with and without Glomus mosseae, to examine the effect of fungus on plant growth and cadmium uptake from the contaminated soil in greenhouse conditions. It was concluded from the study that arbuscular mycorrhiza (AM) inoculation has significantly increased plant growth, cadmium uptake, and bioremediation of cadmium from the soil. The accumulation of cadmium in the African marigold plants was found to be significant in the treatments with AM inoculation when compared with control (uninoculated) plants at different cadmium concentrations (0, 5, 10, 25, 50, 100 ppm). The results proved that the African marigold with Glomus mosseae can be a potential candidate in reducing environmental pollution and in the sustainable ecological restoration of cadmium contaminated sites. Copyright © 2020 Inderscience Enterprises Ltd.
Suitability of extractants for predicting availability of cadmium in inceptisol, alfisol and vertisol
(Enviro Media, 2016) Asha Sahu; S.K. Singh; Nisha Sahu; M.C. Manna
Heavy metals are potentially toxic to human life and the environment. Various extraction procedures were employed for measuring extractable concentrations of potential toxic elements in soil. In a greenhouse pot experiment, three taxonomically different soil orders viz. Typic Ustochrepts (alluvial soil), Typic Rhodustalfs (red soil) and Entic Chromusterts (karail soil) with pH ranging from 5.7 to 8.2 were used. These soils were artificially spiked with different Cd levels (0,5,10,25,50 and 100 mg Cd kg-1). After one month of incubation, extractability of Cd in soils was compared by six extractants:DTPA, AB-DTPA, Mehlich 1, Mehlich III, 0.1 N HC1 and CH3COOH to predict Cd bioavailability in soils. African Marigold (Tagetes erecta L.) was used as test species. Suitability of these extractants in relation to plant tissue concentration and uptake of Cd were also investigated. Extractability of Cd in soils varied depending on extractants used. It was found that 0.1 N HC1 extracted the largest portion of Cd irrespective of soil types. Correlation study of Cd content in soil extracted by different extractants with plant tissue concentration and uptake revealed that best extractant was AB DTP A in Typic Ustochrepts, Mehlich 1 in Typic Rhodustalfs and CH3COOH in Entic Chromusterts. Copyright © EM International.