Effect of pencycuron on microbial parameters of waterlogged soil
05 Dec 2006-Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes (Taylor & Francis Group)-Vol. 41, Iss: 8, pp 1319-1331
TL;DR: The metabolically activated microbial population was more suppressed compared to the dormant population and the DCM amendment did not seem to have any counteractive effect on the toxicity of pencycuron on the microbial variables.
Abstract: A laboratory study was conducted to monitor the effect of pencycuron [1-(4-chlorobenzyl)-1-cyclopentyl-3-phenylurea] on microbial parameters of alluvial (AL) soil (Typic udifluvent) and coastal saline (CS) soil (Typic endoaquept) under waterlogged condition. Pencycuron at field rate (FR), 2FR and 10FR affected the microbial biomass C (MBC), soil ergosterol content and fluorescein diacetate hydrolyzing activity (FDHA) differentially. The DCM amendment did not seem to have any counteractive effect on the toxicity of pencycuron on the microbial variables. The change in microbial metabolic quotient (qCO2) and microbial respiration quotient (QR), indicated pencycuron induced disturbance at 10FR. Present study revealed that the metabolically activated microbial population was more suppressed compared to the dormant population.
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568 citations
01 Jan 1981
TL;DR: Fluorescein diacetate (FDA) was applied as a vital stain to soil bacteria in pure cultures, sterilized soil, and natural soils as discussed by the authors, and nearly 80% of the isolates were stained.
Abstract: Fluorescein diacetate (FDA) was applied as a vital stain to soil bacteria in pure cultures, sterilized soil, and natural soils. The staining ability of FDA was tested on 111 isolates of soil bacteria in pure cultures in a diluted laboratory medium and in sterilized soil. Nearly 80% of the isolates were stained. In a growth experiment in sterilized soil, FDA was compared to acridine orange (AO). At a given time, when most bacteria were considered metabolically active, the number of FDA-stained bacteria exceeded that stained by AO. The staining efficiency and the simple procedure indicate that the FDA-method is useful for estimating the number of metabolically active bacteria in soil. This was confirmed by examination of ten different soils, where the FDA-method was compared to AO-staining, fluorescein isothiocyanate (FITC)-staining, and plate counts.
151 citations
TL;DR: The present finding suggests that the mesorhizobial isolate endowed with multiple properties could be used to facilitate the productivity of chickpea under insecticidestressed soils.
Abstract: An experiment was carried out to determine the plant growth-promoting activities of fipronil- and pyriproxyfen-tolerant Mesorhizobium isolates in the presence and absence of insecticides. The bioremediation and plant growth-promoting potentials of Mesorhizobium isolate (MRC4) was assessed using chickpea as a test crop grown under fipronil- and pyriproxyfen-stressed soils. In this study, the most promising mesorhizobial isolate (MRC4) tolerated fipronil and pyriproxyfen up to a concentration of 1600 μg ml−1 and 1400 μg ml−1, respectively. Isolate MRC4 produced a substantial amount of indole acetic acid (44.3 μg ml−1), salicylic acid (35 μg ml−1), 2,3 di-hydroxybenzoic acid (19 μg ml−1), and exo-polysaccharides (21 μg ml−1) in the absence of insecticides. The plant growth-promoting substances displayed by the isolate MRC4 declined progressively with increasing concentrations of each insecticide. The insecticide tolerant isolate MRC4 was further tested for its effect on chickpea plants grown in fipronil- and pyriproxyfen-treated soils. The insecticide-tolerant isolate MRC4 increased the dry matter accumulation progressively. A maximum increase of 80 (at 600 μg kg−1 soil of fipronil) and 118% (at 3900 μg kg−1 soil of pyriproxyfen) was recorded 135 days after sowing when compared to noninoculated plants treated with the same rates of each insecticide. Moreover, Mesorhizobium isolate MRC4 when used in fipronil- and pyriproxyfen-treated soil also increased symbiotic properties (nodulation and leghaemoglobin content), root N, shoot N, root P, shoot P, seed yield, and seed protein compared to the un-inoculated but treated solely with insecticide. The present finding suggests that the mesorhizobial isolate endowed with multiple properties could be used to facilitate the productivity of chickpea under insecticidestressed soils.
63 citations
Cites background from "Effect of pencycuron on microbial p..."
...After application, a large portion of insecticides accumulate in the top soil layer (0-10 cm) and exert deleterious effects on microbial diversity (Das et al. 2005) thereby leading to a loss in soil fertility (Pal et al. 2006)....
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...2005) thereby leading to a loss in soil fertility (Pal et al. 2006)....
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TL;DR: Of the various concentrations of the two insecticides, pyriproxyfen showed comparatively more severe toxicity to pea plants by decreasing plant biomass, symbiotic attributes, nutrients (nitrogen and phosphorus) uptake, seed yield and grain protein over the uninoculated control.
48 citations
01 Jan 2011
TL;DR: The present review focuses on the role of naturally occurring rhizosphere microbes involved in degradation or transformation of insecticides.
Abstract: Modern application of insecticides belonging to different chemical families to boost agricultural productivity has led to their accumulation in soils to levels that affect, directly and indirectly, soil enzyme activities and physiol-ogical characteristics of nontarget soil microflora including plant growth-promoting rhizobacteria, and, consequently the performance of crop plants. Various biological strategies can be applied for removing toxic substances, including insecticides, from the environment and are collectively known as bioremediation. Among biological approaches, the use of microbes with degradative ability is considered the most efficient and cost-effective option to clean pesticide-contaminated sites. The present review focuses on the role of naturally occurring rhizosphere microbes involved in degradation or transformation of insecticides.
29 citations
Cites background from "Effect of pencycuron on microbial p..."
...This study revealed that the metabolically activated microbial population was more suppressed compared to the dormant population ( Pal et al. 2006 )....
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...Subsequently, abnormally high concentrations of insecticides may lead to a considerable loss in soil fertility ( Pal et al. 2006 )....
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References
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TL;DR: In this paper, a more sensitive method is proposed adapted from the original method, which provides a more accurate determination of FDA hydrolysis in a wide range of soils, including sandy and clayy soils.
Abstract: Fluorescein diacetate (FDA) hydrolysis is widely accepted as an accurate and simple method for measuring total microbial activity in a range of environmental samples, including soils. Colourless fluorescein diacetate is hydrolysed by both free and membrane bound enzymes, releasing a coloured end product fluorescein which can be measured by spectrophotometry. The current method for measuring FDA hydrolysis in soils is limited in its application. FDA activity was very low in sandy and clayey soils. The low activity observed for these soil types was made difficult to measure by the original authors’ choice of solvent for terminating the hydrolysis reaction. Acetone (50% v/v) was found to be most efficient at stopping the hydrolysis reaction. During this study acetone (50% v/v) was found to cause a decrease of approximately 37% in the absorbance of fluorescein produced by the soil samples measured. Although this colour loss is independent of initial fluorescein concentration, it makes the measurement of FDA hydrolytic activity extremely difficult in soils with low microbial activity i.e. sandy and/or clayey soils. Chloroform/methanol (2:1 v/v) was found to successfully stop the hydrolysis reaction for up to 50 min in a range of soil samples without causing the loss of colour observed with acetone. By changing the solvent used for terminating the hydrolysis reaction, low activity soils could be measured successfully. Other parameters of the hydrolysis reaction were optimised for the measurement of soil samples including effect of pH, optimum temperature of incubation, amount of soil, time of incubation, amount of substrate and preparation of suitable standards. A new, more sensitive method is proposed adapted from the original method, which provides a more accurate determination of FDA hydrolysis in a wide range of soils.
905 citations
"Effect of pencycuron on microbial p..." refers methods in this paper
...Fluorescein Diacetate Hydrolyzing Activity (FDHA) Measurement of FDHA is a promising method for determining the overall soil microbial activity and is advantageous over individual soil enzyme assays, as enzymes are substrate specific.[35,36] The hydrolysis of fluorescein diacetate is simultaneously mediated by proteases, lipases and esterases....
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TL;DR: In this paper, the suitability of qCO2 as an bioindicator using data from the Franz Josef Glacier chronosequence, spanning over 22,000 years, and data recalculated from published studies was investigated.
Abstract: The microbial metabolic quotient (respiration-to-biomass ratio) or qCO2, conceptually based on Odum's theory of ecosystem succession, is increasingly being used as an index of ecosystem development (during which it supposedly declines) and disturbance (due to which it supposedly increases). We investigated the suitability of qCO2 as an bioindicator using: (1) data from the Franz Josef Glacier chronosequence, spanning over 22,000 years; and (2) data recalculated from published studies. In the Franz Josef sequence, a detectable decline in qCO2 occurred in the first 250 years in both the L-layer and mineral soil layer. However, in the later phases of the succession there was a sharp increase in qCO2 indicating reduced microbial efficiency, which appeared to be related to stress (independent of disturbance) resulting from steady-state conditions. Calculation of qCO2 from three previous studies on disturbance and ecosystem development indicated that this index responds unpredictably and does not necessarily decline during succession. Plant litter decomposition studies demonstrate that while qCO2 usually declines initially, a significant increase in qCO2 can eventually follow on litter types resistant to decomposition. Correlation analysis of each of 24 previous studies demonstrated that qCO2 often declines with increasing pH, clay content and amounts of microbial biomass; these three soil properties are all indicative of varying stress rather than disturbance levels. Reanalysis of data from 16 previous studies indicated that some disturbances such as fertilization and liming can either increase or decrease qCO2 values depending on whether the disturbance alleviates stress (reducing qCO2)or is more extreme than the stress it alleviates (enhancing qCO2). Although cultivation represents a severe disturbance, qCO2 is not predictably enhanced by this perturbation. While qCO2 undoubtedly provides a useful measure of microbial efficiency, our data suggests it has limitations because it can be insensitive to disturbance and ecosystem development, fails to distinguish between effects of disturbance and stress, and does not decline predictably in response to ecosystem development whenever stress increases along successional gradients.
730 citations
"Effect of pencycuron on microbial p..." refers background in this paper
...The activity and size of soil microbial populations are enhanced with greater organic C contents.[27]...
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26 Oct 2015
TL;DR: Dick et al. as mentioned in this paper discussed soil enzyme activities as a potential biochemical/biological indicator of soil quality and found that soil biological parameters may hold potential as early and sensitive indicators of soil ecological stress or restoration.
Abstract: With the increasing pressure to produce more food, fiber, and fuel to meet world demands on a limited land area, there is an unprecedented need to address global concerns about soil degradation. Understanding the underlying biological processes in tandem with identification of early warning indicators of ecosystem stress is needed to provide strategies and approaches for land resource managers and policymakers to promote long-term ecosystem sustainability. Biological and biochemically mediated processes in soils are fundamental to terrestrial ecosystem function. Ultimately, all members of the food web are dependent on the soil as a source of nutrients, and for degradation and cycling of complex organic compounds. Primary decomposers of organic matter provide energy that supports the activities of organisms from a number of trophic levels in soils. Historically, chemical and physical properties have been used as crude measures of soil productivity. Most notably, determination of soil organic matter has been related to general soil tilth. Soil organic matter changes very slowly, and therefore, many years may be required to measure changes resulting from perturbations. However, there is growing evidence that soil biological parameters may hold potential as early and sensitive indicators of soil ecological stress or restoration (Dick, 1992; Dick & Tabatabai, 1992). In Chapter 5 (this book) information is provided on soil quality in relation to soil microorganisms. In this chapter, soil enzyme activities will be discussed as a potential biochemical/biological indicator of soil quality.
640 citations
TL;DR: The Cmier/Corg ratio proved to be a reliable soil microbial parameter for describing changes in man-made ecosystems and can be considered superior to its single components (Cmier or Corg) and to other parameters.
Abstract: The interrelationship between soil microorganisms and soil organic carbon was studied on an agricultural and on a forest chronosequence of open-pit mine reclamation soils. Thirty years after reclamation, soil carbon levels of 0.8% on the agricultural sites and 1.7% on the forest sites (A-horizon) were reached. Microbial biomass rose very fast to levels characteristic of undisturbed soils. Microbial carbon (Cmier) was 57 mg·100 g−1 soil after 15 years on the agricultural sites and 43 mg·100 g−1 on the forest sites. The contribution of Cmier to the total organic carbon (Corg) decreased with time, more rapidly on the forest sites than on the agricultural ones. From the Cmierr/Corg ratio it became evident that both chronosequences had not yet reached a steady state within the 50 years of reclamation. A significant decrease of the metabolic quotient qCO2 (microbial respiration per unit biomass) with time was observed on the agricultural sites but not on the forest sites. The Cmier/Corg ratio proved to be a reliable soil microbial parameter for describing changes in man-made ecosystems. For evaluating reclamation efforts, the Cmier/Corg ratio can be considered superior to its single components (Cmier or Corg) and to other parameters.
615 citations
"Effect of pencycuron on microbial p..." refers background in this paper
...Microbial Respiration Quotient (QR) The ratio of basal soil respiration to substrate induced respiration, termed as microbial respiration quotient (QR), can be used to assess the effects of various perturbations in soil ecosystems[32,33] and the stability of the soil microbial community....
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568 citations
"Effect of pencycuron on microbial p..." refers background in this paper
...Under such situation, the biochemical activities of these organisms are negligible.[29] Some organisms still persist for long periods in such unfavorable circumstances, possibly due to the production of resistant spores....
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...These groups of organisms are known to be the poorest assimilator of organic carbon, evolving more waste products comprising of CO2 and other low molecular weight organic compounds.[29] The higher magnitude of qCO2 in AL soil than the CS soil could be explained, as different soils have their respective microbial communities with specific activities, adapted to their environments....
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