scholarly journals The Influence of dairy manure on atrazine and 2,4-dichlorophenoxyacetic acid mineralization in pasture soils

1995 ◽  
Vol 75 (3) ◽  
pp. 379-383 ◽  
Author(s):  
James A. Entry ◽  
William H. Emmingham
Keyword(s):  
Microbial Biomass ◽  
Key Words ◽  
Fungal Biomass ◽  
Bacterial Biomass ◽  
Dairy Manure ◽  
Dichlorophenoxyacetic Acid ◽  
Manure Application ◽  
Herbicide Degradation ◽  
Degradation Rates ◽  
2,4 Dichlorophenoxyacetic Acid

The influence of manure application to pasture soils on bacterial and fungal biomass and the atrazine (2 chloro-4 [ethylamino]-6[isopropylamino]-s-triazine) and 2,4-D (2,4 dichlorophenoxyacetic acid) mineralization was assessed in microcosms using radiometric techniques. Additions of 5 tonnes manure ha−1 yr−1 were made to three pasture soils over 20 yr in western Oregon at a rate of 0.42 t ha−1 each month. No manure or fertilizer was added to control treatments. We found greater amounts of total fungal and bacterial biomass in soils that received added manure. There were no differences among active bacterial and fungal biomass between pasture soils that received manure application and pasture soils that received no manure. Greater amounts of atrazine and 2,4-D were mineralized when manure was applied than when soil received no manure or fertilizer. Greater amounts of atrazine and 2,4-D were mineralized in the spring than in summer, fall or winter. Results of this study indicate that the application of dairy manure to pasture soils will significantly increase herbicide degradation rates. Key words: Pasture soils, microbial biomass, manure application, atrazine, 2,4-D, herbicide mineralization

Effect of forest harvesting and slash piling on microbial biomass and respiration in Newfoundland boreal forests

2007 ◽  
Vol 87 (4) ◽  
pp. 455-458 ◽  
Author(s):  
Martin T Moroni ◽  
Paul Q Carter ◽  
Dean W Strickland ◽  
Franz Makeschin ◽  
Don-Roger Parkinson ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Key Words ◽  
Boreal Forests ◽  
Fungal Biomass ◽  
Forest Harvesting ◽  
Organic Layer ◽  
Total Microbial Biomass ◽  
Organic Layers ◽  
Respiration Rates ◽  
Fumigation Extraction

Clearcutting Newfoundland boreal forests significantly reduced organic layer fungal and total microbial biomass in clearcut areas with and without slash cover, compared with forested plots. However, aerobically incubated respiration rates were highest in organic layers from clearcut areas under slash, intermediate under forests, and lowest from clearcut areas without slash. Key words: Carbon, ergosterol, fumigation–extraction, fungal biomass, harvest slash, nitrogen

Biological agents for 2,4-dichlorophenoxyacetic acid herbicide degradation

2019 ◽  
Vol 103 (13) ◽  
pp. 5065-5078 ◽  
Author(s):  
Maria Pilar Serbent ◽  
Andrey Martinez Rebelo ◽  
Adilson Pinheiro ◽  
Adriana Giongo ◽  
Lorena Benathar Ballod Tavares
Keyword(s):  
Biological Agents ◽  
Dichlorophenoxyacetic Acid ◽  
Herbicide Degradation ◽  
2,4 Dichlorophenoxyacetic Acid

scholarly journals Impact of Residue Incorporation on Soil Carbon Storage, Soil Organic Fractions, Microbial Community Composition and Carbon Mineralization in Rice-wheat Rotation – A Review

2021 ◽  
pp. 42-59
Author(s):  
R. K. Naresh ◽  
M. Sharath Chandra ◽  
Aryan Baliyan ◽  
Shakti Om Pathak ◽  
Pradeep Kumar Kanaujiya ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Relative Abundance ◽  
Fungal Biomass ◽  
Bacterial Biomass ◽  
Microbial Biomass C ◽  
No Tillage ◽  
Organic C ◽  
Crop Straw ◽  
Straw Return ◽  
N Treatment

In agroecosystems, straw return is a useful management strategy for increasing soil fertility and crop productivity. The total organic carbon (TOC), dissolved organic C (DOC), and microbial biomass C (MBC) contents all increased significantly when compared to the no straw return (N) and straw return (S) treatments, while the easily oxidizable C content remained same. The S treatment resulted in a 28–52 percent increase in soil light fraction, light fraction organic C, and particle organic C over the N treatment. When compared to the N treatment, crop straw return increased total phospholipid fatty acid (PLFA), bacterial biomass, and actinomycete biomass by 52, 75, and 56 percent, respectively. Under short-term crop straw return, MBC and TOC were the two key determinants determining microbial populations. In comparison to residue removal, residue retention (RR) enhanced SOC storage by 11.3 percent. SOC content and contribution of macro-aggregates in the 0-20 cm depth and micro-aggregates in the 20-40 cm depth rose significantly when no-tillage and straw returns were used together. When no-tillage with straw returning (NTS) was used instead of CT, SOC content, mean weight diameter (MWD), geometric mean diameter (GMD), and fractal dimensions (FD) rose by 25%, 21%, 19%, and 12%, respectively, in the 0-20 cm depth. Soil micro-aggregates were greater in the 20-40 cm depth after CTS treatment. In the 0-20 cm depth, the percentages of macro- and micro-aggregates increased by 60% and 40%, respectively, under NTS. MWD, GMD, > 5, 2-5, 1-2, and 0.25-0.5 mm aggregates all had a positive linear relationship with the SOC. Microbial biomass C (MBC) was considerably enhanced by 20.0 percent when compared to conventional tillage (CT) and no-tillage (NT), but total organic C (TOC), dissolved organic C (DOC), readily oxidizable C (EOC), and SOC of aggregates were not affected. MBC increased by 18.3% and SOC content of 2–1-mm aggregate increased by 9.4% when residue was returned. Total PLFAs grew by 9.8%, while fungal biomass increased by 40.8 percent, thanks to NT. Total PLFAs, bacterial biomass, fungal biomass, F/B, and MUFA/STFA were all increased by 31.1, 36.0, 95.9, 42.5, and 58.8 percent, respectively, while microbial stress was reduced by 45.9%. Wheat straw return had a considerable impact on the bacterial community in the soil, but not on the fungus community. It increased the relative abundance of the bacteria phylum Proteobacteria and the fungal phylum Zygomycota, while decreasing the relative richness of the bacterial phylum Acidobacteria and the fungal phylum Ascomycota. It increased the relative abundance of nitrogen-cycling bacterial taxa including Bradyrhizobium and Rhizobium, among others. This diversity includes bacteria, cyanobacteria, archaea, planctomycetes, and -proteobacteria, as well as endophytes. The system's intricacy and dynamic nature necessitate in-depth research on the three-part interactions between plants, microorganisms, and the soil-water environment.

Influence of vegetation on microbial degradation of atrazine and 2,4-dichlorophenoxyacetic acid in riparian soils

1996 ◽  
Vol 76 (1) ◽  
pp. 101-106 ◽  
Author(s):  
James A. Entry ◽  
William H. Emmingham
Keyword(s):  
Forest Soils ◽  
Mineral Soil ◽  
Bacterial Biomass ◽  
Deciduous Forests ◽  
Coniferous Forests ◽  
Organic Horizon ◽  
Dichlorophenoxyacetic Acid ◽  
Grassland Soils ◽  
Riparian Soils ◽  
2,4 Dichlorophenoxyacetic Acid

Mineralization of atrazine (2 chloro-4 [ethylamino]-6[isopropylamino]-s-triazine) and 2,4-D (2,4-dichlorophenoxyacetic acid) in the organic layer and the top 10 cm of mineral soil was measured with radiometric techniques seasonally in coniferous forests and deciduous forests and grassland riparian soils. Active bacterial biomass and active fungal biomass, total carbon, total nitrogen, and total phosphorus were also measured. In the organic horizon, atrazine mineralization was higher in conifer than in deciduous forests during all seasons. Mineralization of 2,4-D was higher in coniferous than deciduous forests in autumn and spring. Grassland vegetation did not form an organic horizon. In mineral soil, atrazine mineralization was higher in coniferous than deciduous forests in the spring and higher in grassland soils in all seasons of the year. In mineral soil, 2,4-D mineralization was higher in coniferous and deciduous forests than grassland soils in autumn, winter, and spring. 2,4-D mineralization in mineral soils did not differ between coniferous and deciduous forest soils. We found no abiotic variables or active fungal or bacterial biomass that correlated with atrazine or 2,4-D mineralization. We hypothesize that the soil microbial communities that develop under coniferous forests are capable of mineralizing greater amounts of atrazine and 2,4-D than those that develop under deciduous forests or grassland ecosystems. Key words: Forest riparian soils, forest soils, herbicides, microbial biomass

scholarly journals Molecular basis for enantioselective herbicide degradation imparted by aryloxyalkanoate dioxygenases in transgenic plants

2019 ◽  
Vol 116 (27) ◽  
pp. 13299-13304 ◽  
Author(s):  
Jonathan R. Chekan ◽  
Chayanid Ongpipattanakul ◽  
Terry R. Wright ◽  
Bo Zhang ◽  
J. Martin Bollinger ◽  
...  
Keyword(s):  
Catalytic Mechanism ◽  
Biochemical Characterization ◽  
Structural Basis ◽  
Dichlorophenoxyacetic Acid ◽  
Genomic Context ◽  
Synthetic Auxin ◽  
Herbicide Degradation ◽  
Genes Encoding ◽  
Multiple Species ◽  
2,4 Dichlorophenoxyacetic Acid

The synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) is an active ingredient of thousands of commercial herbicides. Multiple species of bacteria degrade 2,4-D via a pathway initiated by the Fe(II) and α-ketoglutarate (Fe/αKG)-dependent aryloxyalkanoate dioxygenases (AADs). Recently, genes encoding 2 AADs have been deployed commercially in herbicide-tolerant crops. Some AADs can also inactivate chiral phenoxypropionate and aryloxyphenoxypropionate (AOPP) herbicides, albeit with varying substrate enantioselectivities. Certain AAD enzymes, such as AAD-1, have expanded utility in weed control systems by enabling the use of diverse modes of action with a single trait. Here, we report 1) the use of a genomic context-based approach to identify 59 additional members of the AAD class, 2) the biochemical characterization of AAD-2 fromBradyrhizobium diazoefficiensUSDA 110 as a catalyst to degrade (S)-stereoisomers of chiral synthetic auxins and AOPP herbicides, 3) spectroscopic data that demonstrate the canonical ferryl complex in the AAD-1 reaction, and 4) crystal structures of representatives of the AAD class. Structures of AAD-1, an (R)-enantiomer substrate-specific enzyme, in complexes with a phenoxypropionate synthetic auxin or with AOPP herbicides and of AAD-2, which has the opposite (S)-enantiomeric substrate specificity, reveal the structural basis for stereoselectivity and provide insights into a common catalytic mechanism.

scholarly journals Probing the Functional Diversity of Global Pristine Soil Communities with 3-Chlorobenzoate Reveals that Communities of Generalists Dominate Catabolic Transformation

2013 ◽  
Vol 79 (22) ◽  
pp. 6932-6940 ◽  
Author(s):  
Albert N. Rhodes ◽  
Roberta R. Fulthorpe ◽  
James M. Tiedje
Keyword(s):  
Functional Diversity ◽  
Boreal Forests ◽  
Molecular Diversity ◽  
Population Heterogeneity ◽  
Microbial Populations ◽  
Dichlorophenoxyacetic Acid ◽  
Degradation Rates ◽  
Undisturbed Soils ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Xenobiotic Degradation

ABSTRACTUnderstanding of functional diversity of microbial populations has lagged description of their molecular diversity. Differences in substrate specificity, kinetics, products, and regulation can dramatically influence phenotypic variation among closely related strains, features that are missed when the strains studied are the fastest-growing and most easily isolated from serial enrichments. To investigate the broader bacterial diversity underlying degradation of anthropogenic chemicals in nature, we studied the 3-chlorobenzoate (3-CBA) degradation rate in a collection of aerobic 3-CBA degraders previously isolated from undisturbed soils in two representative ecosystems: (i) Mediterranean sclerophyllous woodlands in California, Chile, South Africa, and Australia and (ii) boreal forests in Canada and Russia. The majority of isolates degraded 3-CBA slowly and did not completely mineralize 1.0 mM 3-CBA within 1 week. Those with intermediate degradation rates had incomplete degradation pathways and produced colored intermediates indicative of chlorocatechol, a product likely metabolized by other members of the community. About 10% of the isolates grew rapidly and mineralized greater than 90% of the 3-CBA, but because of population heterogeneity in soil, they are likely not large contributors to a soil's total transformation capacity. This suggests that xenobiotic degradation in nature is carried out by a community of cometabolic generalists and not by the efficient specialists that have been traditionally studied in the laboratory. A subset of 58 genotypically distinct strains able to degrade >80% of the 3-CBA was examined for their catabolic versatility using 45 different compounds: mono- and dichlorinated benzoates, phenols, anilines, toluenes, nitrobenzenes, chlorobenzenes, and 2,4-dichlorophenoxyacetic acid. The isolates degraded from 2 to more than 30 compounds with a median of 7, but there was no correlation to habitat of isolation or 3-CBA activity. However, these findings were indicative of finer-scale functional diversity.

In Vitro Shoot Regeneration from Callus Derived from Marubakaido Apple Rootstock under Different Aluminium Concentrations

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 460e-460 ◽  
Author(s):  
Marisa F. de Oliveira ◽  
Gerson R. de L. Fortes ◽  
João B. da Silva
Keyword(s):  
Shoot Regeneration ◽  
Dichlorophenoxyacetic Acid ◽  
Apple Rootstock ◽  
Under Five ◽  
Significant Difference ◽  
Previously Treated ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
In Vitro Shoot Regeneration

The aim of this work was to evaluate the organogenesis of Marubakaido apple rootstock under different aluminium concentratons. The explants were calli derived from apple internodes treated with either 2,4-dichlorophenoxyacetic acid or pichloram at 0.5 and 1.0 μM and under five different aluminium concentrations (0, 5, 10, 15, 20 mg/L). These calli were then treated with aluminium at 0, 5, 10, 15, and 20 mg/L. It was observed shoot regeneration only for those calli previously treated with pichloram. There were no significant difference among the aluminium concentrations.

Characterization of the Reproductive Mode in Guayule In Vitro

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 483a-483
Author(s):  
Roy N. Keys ◽  
Dennis T. Ray ◽  
David A. Dierig
Keyword(s):  
Field Experiments ◽  
Reproductive Mode ◽  
Dichlorophenoxyacetic Acid ◽  
Initial Field ◽  
Breeding Lines ◽  
Reproductive Modes ◽  
Desert Southwest ◽  
2,4 Dichlorophenoxyacetic Acid

Guayule (Parthenium argentatum Gray, Asteraceae) is a latex-producing perennial desert shrub that is potentially of economic importance as an industrial crop for the desert Southwest. It is known to possess complex reproductive modes. Diploids are predominantly sexual and self-incompatible, while polyploids show a range of apomictic potential and self-compatibility. This paper describes the development of a relatively rapid and simple technique for characterizing reproductive modes of breeding lines of P. argentatum. Initial field experiments were based on an auxin test used successfully to characterize reproductive mode in the Poaceae. The application of 2,4-dichlorophenoxyacetic acid inhibited embryo formation in P. argentatum, but this was not the case with other auxins tested. Results of field experiments were ambiguous because: 1) the floral structure of P. argentatum is such that auxins might not have penetrated to the ovules, and 2) there was potential self-fertilization by pollen released within isolation bags. Therefore, in vitro culture of flower heads was tested because it provided much better control of environmental conditions, growth regulator application, and pollen release. Auxin alone, or in combination with gibberellic acid or kinetin, inhibited parthenogenesis in vitro. Embryo production did not vary using two substantially different nutrient media. In vitro flower head culture using a (Nitsch and Nitsch) liquid nutrient medium without growth regulators, enabled characterization of the reproductive mode of seven breeding lines, ranging from predominantly sexual to predominantly apomictic. The results of this technique were substantiated using RAPD analyzes of progeny arrays from controlled crosses.

The role of a metabolic intermediate in the biodegradation of inhibitory substrates

1997 ◽  
Vol 36 (10) ◽  
pp. 27-36 ◽  
Author(s):  
P. Mungkarndee ◽  
S. M. Rao Bhamidimarri ◽  
A. J. Mawson ◽  
R. Chong
Keyword(s):  
The Other ◽  
Metabolic Product ◽  
Dichlorophenoxyacetic Acid ◽  
Mutual Inhibition ◽  
Metabolic Intermediate ◽  
Batch Cultures ◽  
Ortho Cresol ◽  
2,4 Dichlorophenoxyacetic Acid

Biodegradation of the mixed inhibitory substrates, 2,4-dichlorophenoxyacetic acid (2,4-D) and para-chloro-ortho-cresol (PCOC) was studied in aerobic batch cultures. Each substrate added beyond certain concentrations inhibited the degradation of the other. This mutual inhibition was found to be enhanced by 2,4-dichlorophenol (2,4-DCP) which is an intermediate metabolic product of 2,4-D. When 2,4-DCP accumulated to approximatelY 40 mg/l degradation of all compounds in the mixed 2,4-D and PCOC substrate system was completely inhibited. The degradation of 2,4-D and PCOC individually was also found to be inhibited by elevated concentrations of 2,4-DCP added externally, while PCOC inhibited the utilization of the intermediate.

2,4-dichlorophenoxyacetic acid through lactation induces astrogliosis in rat brain

1997 ◽  
Vol 30 (3) ◽  
pp. 175-185 ◽  
Author(s):  
A. Brusco ◽  
J. Pecci Saavedra ◽  
G. García ◽  
P. Tagliaferro ◽  
A. M. Evangelista de Duffard ◽  
...  
Keyword(s):  
Rat Brain ◽  
Dichlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid
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