Responses of soil microorganisms to volatile exudates from germinating pea seeds

1985 ◽  
Vol 63 (6) ◽  
pp. 1040-1045 ◽  
Author(s):  
J. M. Norton ◽  
G. E. Harman
Keyword(s):  
Soil Microorganisms ◽  
Sclerotium Rolfsii ◽  
Hyphal Growth ◽  
Soil Microbial Activity ◽  
Soil Microflora ◽  
Natural Soil ◽  
Soil Microbial ◽  
Aged Seed ◽  
Seed Rot ◽  
Pea Seeds

Responses of soil microorganisms to volatile exudates from germinating pea seeds of differing quality were determined. Germination of sclerotia of Rhizoctonia solani and Sclerotium rolfsii and subsequent hyphal growth were stimulated by exposure to volatiles from aged but not nonaged pea seeds. Hyphae grew preferentially toward aged seeds. In natural soil, bacterial and fungal populations showed significant increases after exposure to volatiles from aged seed. For example, Fusarium spp. and Pseudomonas spp. showed increases of 79 and 2200%, respectively, over their original population levels after a 48-h exposure to volatiles. Conversely, Pythium populations and associated seed-rotting potential of soil decreased in natural soils exposed to volatiles. In autoclaved soils infested with P. ultimum (PHP4), Pythium populations increased dramatically after exposure to volatiles from aged pea seeds. In soils infested with either soil fungi or bacteria in addition to P. ultimum, Pythium levels remained constant or decreased, respectively, with time of exposure. Exposure to the volatiles from aged pea seeds stimulated soil microbial activity. These results suggest that Pythium germlings, when unable to reach a host, are subjected to microbial antagonism in the presence of the native soil microflora. A decrease in cucumber seed rot coincided with decreases in Pythium numbers.

scholarly journals Combined Soil Treatments and Sequence of Application in Improving the Control of Soilborne Pathogens

2000 ◽  
Vol 90 (7) ◽  
pp. 751-757 ◽  
Author(s):  
Dani Eshel ◽  
Abraham Gamliel ◽  
Avshalom Grinstein ◽  
Pietro Di Primo ◽  
Jaacov Katan
Keyword(s):  
Microbial Activity ◽  
Fungal Pathogens ◽  
Sclerotium Rolfsii ◽  
Field Tests ◽  
Soil Microbial Activity ◽  
Soil Microbial ◽  
Pathogen Control ◽  
Opposite Sequence ◽  
Field Plots ◽  
Metham Sodium

The effects of reduced doses of methyl bromide (MB) or metham sodium, heating, short solarization, and soil microbial activity, alone or in combination, on survival of soilborne fungal pathogens were tested in a controlled-environment system and field plots. Sublethal doses of heating or MB delayed germination of Sclerotium rolfsii sclerotia. Combining MB and heating treatments was more effective than either treatment alone in controlling S. rolfsii and Fusarium oxysporum f. sp. basilici. The application heating followed by fumigation with MB, was significantly more effective in delaying and reducing germination of S. rolfsii sclerotia and in controlling F. oxysporum f. sp. basilici than the opposite sequence. Further, incubation in soil and exposure to microbial activity of previously heated or MB-treated sclerotia increased the mortality rate, indicating a weakening effect. Similarly, incubation of chlamydospores of F. oxysporum f. sp. melonis and F. oxysporum f. sp. radicis-lycopersici in soil in the field after fumigation further reduced their survival, confirming the laboratory results. In field tests, combining MB or metham sodium at reduced doses with short solarization was more effective in controlling fungal pathogens than either treatment alone. Treatment sequence significantly affected pathogen control in the field, similar to its effect under controlled conditions. This study demonstrates a frequent synergistic effect of combining soil treatments and its potential for improving pathogen control and reducing pesticide dose, especially when an appropriate sequence was followed.

scholarly journals Soil Microbial Community Structure and Target Organisms under Different Fumigation Treatments

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Sadikshya R. Dangi ◽  
James S. Gerik ◽  
Rebecca Tirado-Corbalá ◽  
Husein Ajwa
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
Methyl Bromide ◽  
Soil Microorganisms ◽  
Phospholipid Fatty Acid ◽  
Natural Soil ◽  
Soil Microbial Community Structure ◽  
Soil Microbial ◽  
Field Samples

Producers of several high-value crops in California rely heavily on soil fumigants to control key diseases, nematodes, and weeds. Fumigants with broad biocidal activity can affect both target and nontarget soil microorganisms. The ability of nontarget soil microorganisms to recover after fumigation treatment is critical because they play an important role in sustaining the health of agricultural and natural soil systems. Fumigation trial was conducted in Parlier, CA, and the study focuses on the effects of different rates of Telone C35 and also methyl bromide fumigation with polyethylene (PE) and totally impermeable film (TIF) tarps on target and nontarget soil microorganisms using field samples. Results indicated that the populations of target organisms, such asFusarium oxysporumandPythiumspp., were reduced at all rates of fumigants. Phospholipid fatty acid (PLFA) analysis indicated that all major nontarget soil microbial groups such as Gram positive bacteria, Gram negative bacteria, fungi, and arbuscular mycorrhizal fungi (AMF) were affected by methyl bromide (MeBr) fumigation treatment. In general, the effects of Telone C35 (299 L/ha) under PE tarp had the least impact on microbial community structure and better effect on controlling target microorganisms and, therefore, indicated the better option among fumigation treatments.

Soil Microbial and Enzyme Properties as Affected by Long-Term Exposure to Phthalate Esters

2013 ◽  
Vol 726-731 ◽  
pp. 3653-3656 ◽  
Author(s):  
Hui Lun Chen ◽  
Jun Yao ◽  
Fei Wang
Keyword(s):  
Microbial Activity ◽  
Soil Microorganisms ◽  
Phthalate Esters ◽  
Soil Microbial Activity ◽  
Inhibitory Effect ◽  
Dioctyl Phthalate ◽  
Dimethyl Phthalate ◽  
Soil Microbial ◽  
Long Term Impact

In this study, an isothermal microcalorimetry was used to demonstrate the long-term impact of dimethyl phthalate (DMP), dipropyl phthalate (DBP), dioctyl phthalate (DOP) and dicyclohexyl phthalate (DEHP) on the soil microbial activity. Generally, the toxicity order of four phthalate esters (PAEs) is DBP>DMP>DOP>DEHP. The PAEs show inhibitory effect when the soil was exposed to PAEs for 10 days and the PAEs will have a small stimulate effect after 30 days, and then the PAEs inhibit the soil microorganisms again. The effect of PAEs on soil microbial activity is almost the same as those on urease activity.

EFFECT OF FOLIAR TREATMENT OF VEGETATIVE PLANTS ON SOIL MICROBIAL FLORA

1970 ◽  
pp. 19-23
Author(s):  
N. V. Fomicheva ◽  
G. Yu. Rabinovich ◽  
Yu. D. Smirnova
Keyword(s):  
Soil Microorganisms ◽  
Peat Soil ◽  
Analysis Data ◽  
Soil Microflora ◽  
Small Scale ◽  
Active Principle ◽  
Nitrogenous Compounds ◽  
Soil Microbial ◽  
Foliar Treatment ◽  
Positive Effect

The article contains materials of scientific research reflecting the positive effect on the soil microflora of foliar treatment of vegetative plants with various preparations. A small-scale experiment on growing carrots on low-lying peat soil of the Yakhroma floodplain (Moscow region) was carried out. For foliar treatments were applied biological means, developed at VNIIMZ – biological product LPB (the active principle – agronomically useful microflora) and biological means BoHum (the active principle – humic substances). Spraying was carried out three times per season at a rate of flow of a working solution of 300 l / ha (dilution 1: 100, 1: 300, 1: 500). To assess the effect of biological means on soil processes in soil samples, the number of ammonifying, amylolytic and phosphate-mobilizing microorganisms was determined. The intensity of the mineralization processes in the soil was estimated from the value of the mineralization coefficient. It was established that the foliar treatment of vegetative plants carrot with biological means of LPB and BoHum increased the total number of identified soil microorganisms by 21-22%, while the mineralization of nitrogenous compounds in the soil during spraying with humic bio means occurred more intensively 3 times, and the biologic preparation of LPB 2.3 times, concerning the control. Activation of soil-microbiological processes (due to bio means entering the soil), together with the activation of physiological processes of plant growth and development (as a result of contact with bio means on the leaf plate of plants) increased carrot yield by 19.4 and 18.3%, respectively, when using LPB and BoHum in 1: 300 dilutions. The regression analysis data confirmed a statistically significant relationship between carrot yield and the total number of soil microorganisms (r = 0.67) and soil mineralization coefficient (r = 0.77). The positive effect of foliar treatments on the soil microflora was also revealed in the cultivation of spring wheat and potatoes.

scholarly journals Reaction of Microorganisms to Long-Term Waste Reclamation of Soil Degraded by the Sulfur Mining Industry

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1226
Author(s):  
Jolanta Joniec ◽  
Grażyna Żukowska ◽  
Marta Bik-Małodzińska ◽  
Edyta Kwiatkowska ◽  
Kamila Rojek
Keyword(s):  
Soil Microorganisms ◽  
Initial Period ◽  
Mining Industry ◽  
Soil Condition ◽  
Soil Microbial Activity ◽  
Mineral Wool ◽  
Degraded Soil ◽  
Soil Microbial ◽  
Waste Reclamation

The research was carried out to assess soil condition many years after waste introduction for reclamation purposes. The parameters of the activity of soil microorganisms responsible for the revitalization processes in degraded soils were used in the research. Soil material was derived from the area of the former sulfur mine. The results showed that even a single waste introduction to degraded soil caused long-lasting effects in the activity of soil microorganisms. The most favorable changes were caused by the addition of sewage sludge and the use of mineral wool in the form of a pad. The application of lime alone turned out to be the least beneficial for the revitalization processes, i.e., restoring the homeostasis of biological life in degraded soil. This research is a continuation of study that concerned the initial recultivation period. The obtained research results show the need for monitoring soils reclaimed with waste, not only in the initial period but also in the following years. These results allow evaluation of the usefulness of the parameters of soil microbial activity in monitoring soil environments subjected to strong human pressure. The results can be used to assess the risks associated with the introduction of waste into the environment.

scholarly journals SOIL SOLARIZATION IN THE CONTROL OF BEAN DISEASES CAUSED BY Sclerotium rolfsii

2019 ◽  
Vol 94 (1) ◽  
pp. 1
Author(s):  
Vanessa Nataline Tomazeli ◽  
Idalmir Dos Santos ◽  
Rafael Gustavo Ferreira Morales ◽  
Alex Sandro Torre Figueiredo
Keyword(s):  
Experimental Design ◽  
Standard Treatment ◽  
Sclerotium Rolfsii ◽  
Soil Microbial Activity ◽  
Soil Solarization ◽  
Stem Rot ◽  
First Year ◽  
Soil Microbial ◽  
Bean Plants ◽  
Severity Of The Disease

This study aimed at assessing the effects of soil solarization on diseases caused by Sclerotium rolfsii in bean plants. Treatments consisted of solarization of a soil previously infested with S. rolfsii and a standard treatment (no solarization). A randomized block experimental design was adopted, with four replications. We assessed disease severity by measuring emergence, final stand, incidence, and severity of the disease. Soil microbial activity and number of viable sclerotia were evaluated after the second crop was grown in the first year of the experiment. Soil solarization reduced the incidence and severity of stem rot caused by the fungus S. rolfsii in beans, as well as sclerotia viability. However, solarization was not effective for total control of the pathogen.

Influence of volatiles from healthy and decaying sweet potato storage roots on sclerotial germination and hyphal growth of Sclerotium rolfsii

1989 ◽  
Vol 67 (1) ◽  
pp. 53-57 ◽  
Author(s):  
C. A. Clark
Keyword(s):  
Sweet Potato ◽  
Sclerotium Rolfsii ◽  
Hyphal Growth ◽  
Root Tissue ◽  
Natural Soil ◽  
Potato Storage ◽  
Storage Root ◽  
Storage Roots ◽  
Sweet Potatoes ◽  
Directional Growth

Volatiles released from sweet potato storage root tissue infected by different sweet potato storage root pathogens stimulated eruptive germination of sclerotia of Sclerotium rolfsii but did not influence the direction of hyphal growth on agarose. Volatiles from healthy sweet potato storage root tissue did not affect percent hyphal or eruptive germination of sclerotia of S. rolfsii but stimulated directional growth of hyphae toward the healthy tissue. In laboratory experiments, the frequency of infection of sweet potato stem segments by S. rolfsii on the surface of natural soil was increased when sclerotia were incubated in the presence of decaying sweet potato storage root tissue. Incidence of sclerotial blight lesions on sprouts in plant beds was increased in the presence of roots infected by Fusarium solani or Erwinia chrysanthemi. Volatiles from decaying sweet potato mother roots may predispose sweet potatoes to sclerotial blight.

scholarly journals Powders of kudzu, velvetbean, and pine bark added to soil increase microbial population and reduce Southern blight of soybean

2006 ◽  
Vol 31 (6) ◽  
pp. 551-556 ◽  
Author(s):  
Luiz E. B. Blum ◽  
Rodrigo Rodríguez-Kábana
Keyword(s):  
Microbial Population ◽  
Disease Incidence ◽  
Soil Amendments ◽  
Sclerotium Rolfsii ◽  
Enterobacter Aerogenes ◽  
Soil Microbial Activity ◽  
Pine Bark ◽  
Southern Blight ◽  
Soil Microbial ◽  
Soil Microbial Population

Southern blight (Sclerotium rolfsii) of soybean (Glycine max) is an important disease throughout the world. Some soil amendments can reduce disease levels by improving soil microbial activity. The main goals of this study were to investigate the effects of soil amendments such as dried powders of kudzu (Pueraria lobata), velvetbean (Mucuna deeringiana), and pine bark (Pinus taeda), on soil microbial population and disease caused by S. rolfsii on soybean. Pine bark, velvetbean (mucuna) and kudzu (25 g kg-1) added to soil were effective in reducing disease incidence [non-amended (NA) ~ 39%; amended (A) ~ 2 to 11%)]. Bacillus megaterium was the bacteria most frequently isolated in soils with velvetbean or kudzu (NA ~ log 5.7 CFU g-1 of dried soil; A ~ log 6.2). Soils with velvetbean and kudzu stimulated increase in population of Enterobacter aerogenes (NA ~ log 3; A ~ log 5.1-5.8). Pseudomonas putida population was higher in A than in NA (NA ~ log 4; A ~ log 5.5), and was negatively correlated (r = -0.83, P = 1%) to disease incidence. Soil amended with kudzu and pine bark stimulated increases in populations of Trichoderma koningii (NA ~ log 1.6; A ~ log 2.9) and Penicillium citreonigrum (NA ~ log 1.3; A ~ log 2.6), respectively. Penicillium herquei soil population increased with addition of kudzu (NA ~ log 1.2; A, ~ log 2.5). These microorganisms are antagonists of soil-borne pathogens. Powders of velvetbean, kudzu, and pine bark can increase antagonistic population in soil and reduce disease.

scholarly journals Effects of heavy metal concentrations on biological activity of soil micro-organisms

2011 ◽  
Vol 49 (No. 7) ◽  
pp. 321-326 ◽  
Author(s):  
M. Šmejkalová ◽  
O. Mikanová ◽  
L. Borůvka
Keyword(s):  
Heavy Metal ◽  
Microbial Activity ◽  
Soil Microbial Activity ◽  
Soil Microflora ◽  
Significant Inhibition ◽  
Metal Concentrations ◽  
Heavy Metal Concentrations ◽  
Soil Microbial ◽  
Cadmium Lead ◽  
Micro Organisms

The distribution of cadmium, lead and zinc in exchangeable, organic, and 2M HNO3-extractable fractions as well as the effect of heavy metal concentrations on soil microflora was investigated. Six sampling transects were chosen in theLitavkaRiveralluvium in 1999–2001. Concentrations of all metals increased with decreasing distance from the source of contamination. The concentrations of Cd and Zn in exchangeable fraction were higher than in organically bound fraction, a reverse trend was found in Pb speciation. All measured parameters of soil microbial activity were affected by heavy metal concentrations. The decrease in CFU was most significant in the case of oligotrophic bacteria and spore-forming bacteria. Significant inhibition of C-biomass occurred in soils highly contaminated by heavy metals. The Cbiomass:Cox ratio decreased with increasing soil pollution. Generally, the values of enzymatic activities were highest in the soil above the source of contamination and they were decreased as approaching the source of contamination. Our results demonstrate that several parameters of microbial activity could be used as good indicators of increasing concentrations of Cd, Pb, and Zn in soil.

Evaluating carbon dynamics and microbial activity in arctic soils under warmer temperatures

2008 ◽  
Vol 88 (1) ◽  
pp. 31-44 ◽  
Author(s):  
Maren Oelbermann ◽  
Michael English ◽  
Sherry L Schiff
Keyword(s):  
Microbial Activity ◽  
Soil Microorganisms ◽  
Microbial Respiration ◽  
Soil Microbial Activity ◽  
Phase 2 ◽  
Metabolic Diversity ◽  
Soil Horizons ◽  
Organic C ◽  
Soil Microbial ◽  
Arctic Soils

A large portion of carbon (C) is stored in the world’s soils, including those of peatlands, wetlands and permafrost. However, there is disagreement regarding the effects of climate change on the rate of organic matter decomposition in permafrost soils of the arctic. In this study it was hypothesized that soil exposed to a higher ambient temperature would have a greater flux of CO2 as well as a change in the metabolic diversity of culturable soil microorganisms. To evaluate this hypothesis we determined soil C dynamics, soil microbial respiration and activity, and 13C and 15N fractionation in laboratory incubations (at 14 and 21°C) for an organic-rich soil (Mesic Organic Cryosol) and a mineral soil (Turbic Cryosol) collected at the Daring Lake Research Station in Canada’s Northwest Territories. Soil organic C (SOC) and nitrogen (N) stocks (g m-2) and concentration (%) were significantly different (P < 0.05) between soil horizons for both soil types. Stable isotope analysis showed a significant enrichment in δ13C and δ15N with depth and a depletion in δ13C and δ15N with increasing SOC and N concentration. In laboratory incubations, microbial respiration showed three distinct phases of decomposition: a phase with a rapidly increasing rate of respiration (phase 1), a phase in which respiration reached a peak midway through the incubation (phase 2), and a phase in the latter part of the incubation in which respiration stabilized at a lower flux than that of the first phase (phase 3). Fluxes of CO2 were significantly greater at 21°C than at 14°C. The δ13C of the evolved CO2 became significantly enriched with time with the greatest enrichment occurring in phase 2 of the incubation. Soil microbial activity, as measured using Biolog EcoplatesTM, showed a significantly greater average well color development, richness, and Shannon index at 21°C; again the greatest change occurred in phase 2 of the incubation. Principal component analysis (PCA) of the Biolog data also showed a change in the distinct clustering of the soil microbial activity, showing that C sources from the soil were metabolized differently with time at 21 than at 14°C, and between soil horizons. Our results show that Canadian arctic soils contain large stores of C, which readily decompose, and that substantial increases in CO2 emissions and changes in the metabolic diversity of culturable soil microorganisms may occur when ambient temperatures increase from 14 to 21°C. Key words: CO2 flux, C fractionation, global warming, soil organic C and N, stable isotopes

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