scholarly journals Effects of pH and Aeration on Sclerotium rolfsii sacc. Mycelial Growth, Sclerotial Production and Germination

2018 ◽  
Vol 7 (3) ◽  
pp. 123-129 ◽  
Author(s):  
Fakher Ayed ◽  
Hayfa Jabnoun-Khiareddine ◽  
Rania Aydi-Ben-Abdallah ◽  
Mejda Daami-Remadi
Keyword(s):  
Mycelial Growth ◽  
Sclerotium Rolfsii ◽  
Dry Weight ◽  
Ph Values ◽  
Effects Of Ph ◽  
Ph Range ◽  
Sclerotial Development ◽  
Sclerotial Germination

Sclerotium rolfsii is one of the devastating soilborne fungus responsible for significant plant losses. The effects of pH and aeration on pathogen mycelial growth, sclerotial production and germination were investigated for three Tunisian isolates. Optimal mycelial growth occurred at pH 6 for Sr2 and Sr3 isolates and at pH 6-7 for Sr1. Dry mycelial growth was optimum at pH values ranging between 4 and 7. Sclerotial initiation started on the 3rd day of incubation at all pH values tested and mature sclerotia were formed after 6 to 12 days. Optimal sclerotial production was noted at pH 5. The dry weight of 100 sclerotia varied depending on isolates and pH and occurred at pH range 4-7. At pH 9, mycelial growth, sclerotial production and dry weight of 100 sclerotia were restricted. The optimum sclerotial germination, noted after 24 h of incubation, varied depending on isolates and pH and occurred at pH 4-9. Mycelial growth was optimum in aerated plates with a significant isolates x aeration treatments interaction. Sclerotial initiation occurred at the 3rd day of incubation and mature sclerotia were observed after 6-9 days. Sclerotial development was very slow in completely sealed plates and dark sclerotia were produced only after 15 days of incubation. The highest sclerotial yields were noted in aerated plates. The highest dry weight of 100 sclerotia for Sr1 isolate was recorded in ½ sealed, no sealed and completely sealed plates, while for Sr2, it was noted in ½ and ⅔ sealed plates. For Sr3, the maximum dry weight of 100 sclerotia was recorded in ½, ⅔ and completely sealed plates. Germination of S. rolfsii sclerotia, after 24 h of incubation, did not vary significantly depending on aeration treatments and ranged from 90 to 100% for all isolates.

scholarly journals Effect of Different Carbon and Nitrogen Sources on Sclerotium rolfsii sacc. Mycelial Growth and Sclerotial Development

2020 ◽  
Vol 9 (1) ◽  
pp. 17-27
Author(s):  
Fakher Ayed ◽  
Hayfa Jabnoun-Khiareddine ◽  
Rania Aydi-Ben Abdallah ◽  
Mejda Daami-Remadi
Keyword(s):  
Ammonium Chloride ◽  
Radial Growth ◽  
Mycelial Growth ◽  
Sodium Citrate ◽  
Ammonium Acetate ◽  
Sclerotium Rolfsii ◽  
N Source ◽  
Sclerotial Formation ◽  
Sclerotial Development ◽  
Sclerotial Germination

In vitro studies were conducted on Potato Dextrose Agar using different carbon (C) and nitrogen (N) sources to evaluate their effects on the mycelial growth, and the sclerotial development of three Tunisian Sclerotium rolfsii Sacc. isolates. Radial growth was optimum on basal medium supplemented with ammonium chloride (0.48 gram of nitrogen per liter (g of N.L-1)) as N source but was restricted on L-Arginine and completely inhibited on ammonium acetate amended media (0.48 g N.L-1). Sclerotial initiation occurred from the 3rd to the 12th day of incubation for all tested isolates. Potassium nitrate was the most suitable N source for sclerotial formation whereas sclerotial development was completely inhibited on ammonium acetate amended medium. Optimal sclerotial germination was recorded using L-Arginine (78-80%) followed by L-Asparagine (46-94%) and ammonium chloride (46-88%) as N sources. Nevertheless, the lowest sclerotial germination rate was noted on sodium nitrate and ammonium acetate amended media. As for C sources (16 gram of carbon per liter (g of C.L-1)), optimal radial growth occurred using D-mannitol for Sr1 and Sr2 isolates and maltose for Sr3, but no mycelial growth was recorded using sodium citrate for all isolates. All C sources tested, except sodium citrate, were suitable for sclerotial formation, production, and germination. Mature sclerotia became brownish after 6 to 12 days of incubation and sclerotial production was highest using D-mannitol, maltose, and D-glucose, depending on isolates used, as C sources. Optimal germination of sclerotia was noted using D-glucose, D-mannitol and maltose for Sr1 isolate, maltose for Sr2 and D-glucose and maltose for Sr3. It was concluded that N and C sources are both important factors for the growth of S. rolfsii and its survival.

scholarly journals Indian Mustard and Allyl Isothiocyanate Inhibit Sclerotium rolfsii

2002 ◽  
Vol 127 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Stephanie G. Harvey ◽  
Heather N. Hannahan ◽  
Carl E. Sams
Keyword(s):  
Treatment Effect ◽  
Radial Growth ◽  
Mycelial Growth ◽  
Sclerotium Rolfsii ◽  
Indian Mustard ◽  
Allyl Isothiocyanate ◽  
Potato Dextrose Agar ◽  
Soilborne Pathogen ◽  
Low Concentrations ◽  
Sclerotial Germination

Allyl isothiocyanate (AITC) is the predominant isothiocyanate produced by damaged tissues of Indian mustard (Brassica juncea (L) Czerniak). This study investigated Indian mustard and AITC mediated suppression of mycelial growth and sclerotial germination of Sclerotium rolfsii Saccardo, a common soilborne pathogen. Indian mustard (IM) treatments of 0, 0.1, 0.2, 0.6, 1.0, 2.0, 4.1, 5.1, 10.2, 20.4, 40.8, 81.6, and 163.3 g·L-1 (weight of reconstituted mustard per liter of air) were evaluated for suppression of mycelial growth. Treatment effect was evaluated by measuring the radial growth of mycelia. Sclerotia were placed in culture tubes containing 18 g autoclaved soil and covered with an additional 5 g soil. AITC at concentrations of 0, 4.0, 16.0, 64.0, 256.0, 1024.0, or 4096.0 μmol·L-1 was injected into the tubes. Treated sclerotia were removed from tubes and plated on potato dextrose agar to determine viability. Mycelial growth was inhibited with IM treatments (P < 0.01). Inhibiting concentrations (IC) of IM for mycelial growth inhibition of 50% and 90% were 0.7 and 1.0 g·L-1, respectively, with death resulting with >2 g·L-1. Inhibition attributable to AITC alone was lower than that achieved by IM producing equivalent amounts of AITC. Germination of sclerotia was negatively correlated with AITC concentration (r = 0.96; P < 0.01). The IC50 and IC90, of AITC were 249.0 and 528.8 μmol·L-1, respectively, at 42 hours. The lethal concentration for sclerotia was not reached; only suppression occurred at the highest treatment concentrations. Sclerotium rolfsii mycelia were sensitive to the IM volatiles and were suppressed at low concentrations. Sclerotia were more resistant than the mycelia and required higher concentrations of AITC to suppress germination.

EFFECTS OF pH AND NITROGEN SOURCES ON GROWTH OF MICROCYSTIS AERUGINOSA KÜTZ.

1962 ◽  
Vol 8 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Jack McLachlan ◽  
P. R. Gorham
Keyword(s):  
Growth Inhibition ◽  
Microcystis Aeruginosa ◽  
Nitrate Nitrogen ◽  
Nitrogen Sources ◽  
Cesium Chloride ◽  
Potassium Nitrate ◽  
Degree Of Ionization ◽  
Ph Values ◽  
Effects Of Ph ◽  
Ph Range

Microcystis aeruginosa Kütz. (strain NRC-1) grew equally well throughout the pH range 6.5 to 10 when provided with suitable media. Toxicity of tris(hydroxymethyl)aminomethane (TRIS) towards the alga was found to decrease as the pH decreased and could be correlated with the degree of ionization of the TRIS molecule. Other organic buffers examined were either toxic at all concentrations and pH values tested or promoted lysis. When TRIS was used as a buffer, higher concentrations of cesium chloride and potassium nitrate were tolerated without growth inhibition at pH 6.5 than at 7.5. In the presence of TRIS, Microcystis grew equally well with nitrate, ammonium, or urea as nitrogen sources. Eight out of 20 amino compounds examined served as nitrogen sources in TRIS-buffered medium, but growth was poorer than with nitrate nitrogen.

scholarly journals Adsorption Properties of Sepiolite in Relation to Uranium and Lanthanide Ions

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 686 ◽  
Author(s):  
Gładysz-Płaska
Keyword(s):  
Adsorption Capacity ◽  
Adsorption Properties ◽  
Lanthanide Ions ◽  
Ambient Conditions ◽  
Initial Concentration ◽  
Ph Values ◽  
Batch Technique ◽  
Effects Of Ph ◽  
Ph Range

The batch technique was used to study the adsorption of La(III), Eu(III), Lu(III), and U(VI) ions on sepiolite and ODTMA–sepiolite under ambient conditions. The effects of pH, time, and initial concentration were investigated. The highest U(VI) adsorption was found on ODTMA-sepiolite in the pH range of 6–8, while in the case of lanthanide ions, adsorption on sepiolite was 80% in the pH range of 4–8 and 98% for pH values above 8. The adsorption capacity of ODTMAsepiolite was found to be 285.6 mg/g for uranium, and raw sepiolite: 142.8 mg/g for U(VI), 91.6 mg/g for La(III), 91.4 mg/g for Eu (III), and 104.9 mol/g for Lu(III). ODTMA–sepiolite turned out to be a weak sorbent for lanthanide ions. Two short- and long-lived fluorescence species were observed in the TRLFS spectra of U(VI) adsorbed on sepiolite at pH 6.5. The average lifetimes of short- (τ1) and long-lived (τ2) fluorescence are τ1 = 2420 ± 430 ns and τ2 = 37950 ± 5710 ns for U-sepiolite; τ1 = 3523 ± 160 ns and τ2 = 45400 ± 1830 ns for U-ODTMA–sepiolite.

Adsorption and desorption of boron by goethite

Soil Research ◽  
1987 ◽  
Vol 25 (4) ◽  
pp. 377 ◽  
Author(s):  
PM Bloesch ◽  
LC Bell ◽  
JD Hughes
Keyword(s):  
Elevated Temperature ◽  
Boron Concentration ◽  
Soil Testing ◽  
Adsorption And Desorption ◽  
Ph Values ◽  
Competing Anions ◽  
Effects Of Ph ◽  
Ph Range ◽  
Best Fit ◽  
Boron Adsorption

The effects of varying pH, concentration of boron, and competing anions on the adsorption of boron were examined. Boron adsorption initially increased with pH, peaked at approximately pH 8, and then declined. The presence of phosphate reduced adsorption over the pH range 5.2-10.6; the effect of sulfate was less than that of phosphate and ceased at about pH 7. The presence of mannitol caused virtually no difference in boron adsorption up to about pH 6, but reduced adsorption at higher values. The model by Bowden and coworkers was successful in describing both the charge characteristics of goethite in the absence of boron adsorption and the effects of pH and boron concentration on adsorption of the element. The best fit of the model was achieved when B(OH)4-, B3O3(OH)4-, B4O5(OH):- and B5O6(OH)4- were considered as the adsorbing species, although B(OH)4- and B4O5(OH)24- were predicted to be the major adsorbing ions. Boron adsorption was found to be reversible with respect to both concentration and pH. Elevated temperature increased the amount of desorption at both pH 6 and 8. The effect of mannitol on boron desorption mirrored the effect of the compound on adsorption of the element; there was no effect up to pH 6, but at higher pH values desorption was increased. The significance of the desorption data for soil testing for boron is discussed.

scholarly journals Optimal Growing Substrate pH for Five Sedum Species

HortScience ◽  
2013 ◽  
Vol 48 (4) ◽  
pp. 448-452 ◽  
Author(s):  
Youbin Zheng ◽  
Mary Jane Clark
Keyword(s):  
Regression Models ◽  
Specific Growth ◽  
Dry Weight ◽  
Growth Responses ◽  
Dragon’S Blood ◽  
Ph Values ◽  
Ph Range ◽  
Species Specific ◽  
Substrate Ph ◽  
Weight Regression

To determine the optimal growing substrate pH values for Sedum plants, Sedum album, Sedum reflexum ‘Blue Spruce’, Sedum spurium ‘Dragon’s Blood’, Sedum hybridum ‘Immergrunchen’, and Sedum sexangulare were grown in containers using peatmoss and perlite-based substrates at five target pH levels (i.e., 4.5, 5.5, 6.5, 7.5, and 8.5). Optimal pH levels, calculated from dry weight regression models, were 6.32, 6.43, 5.71, 6.25, and 5.91 for S. album, S. reflexum, S. spurium, S. hybridum, and S. sexangulare, respectively, and 5.95 overall. Sedum spurium dry weight varied the most among pH treatments (i.e., 9.5 times greater at pH 6.3 vs. 8.3), whereas S. reflexum varied the least (i.e., 1.3 times greater at pH 6.3 vs. 4.4), indicating species-specific growth responses to growing substrate pH. These findings identified a narrow range of optimal growing substrate pH levels within a wider pH range tolerated by five Sedum spp. Therefore, by adjusting substrate pH to optimal levels, Sedum growth can be maximized.

scholarly journals Zinc adsorption in highly weathered soils

2008 ◽  
Vol 43 (1) ◽  
pp. 131-139 ◽  
Author(s):  
José Carlos Casagrande ◽  
Marcio Roberto Soares ◽  
Ernesto Rinaldi Mouta
Keyword(s):  
Ionic Strength ◽  
Ph Value ◽  
Batch Adsorption ◽  
Adsorption Mechanisms ◽  
Ionic Strength Effect ◽  
Ph Values ◽  
Effects Of Ph ◽  
Ph Range ◽  
Highly Weathered Soils ◽  
Zinc Adsorption

The objective of this work was to assess the effects of pH and ionic strength upon zinc adsorption, in three highly weathered variable charge soils. Adsorption isotherms were elaborated from batch adsorption experiments, with increasing Zn concentrations (0-80 mg L-1), and adsorption envelopes were constructed through soil samples reactions with 0.01, 0.1 and 1 mol L-1 Ca(NO3)2 solutions containing 5 mg L-1 of Zn, with an increasing pH value from 3 to 8. Driving force of reaction was quantified by Gibbs free energy and separation factor. Isotherms were C-, H- and L-type and experimental results were fitted to nonlinear Langmuir model. Maximum adsorption ranged from 59-810 mg kg-1, and Zn affinity was greater in subsoil (0.13-0.81 L kg-1) than in the topsoil samples (0.01-0.34 L kg-1). Zinc adsorption was favorable and spontaneous, and showed sharply increase (20-90%) in the 4-6 pH range. No effect of ionic strength was observed at pH values below 5, because specific adsorption mechanisms predominated in the 3-5 pH range. Above pH 5, and in subsoil samples, Zn was adsorbed by electrostatic mechanisms, since ionic strength effect was observed. Despite depth and ionic strength effects, Zn adsorption depends mainly on the pH.

scholarly journals Toxicity and Resistance Potential of Selected Fungicides to Galactomyces and Penicillium spp. Causing Postharvest Fruit Decays of Citrus and Other Crops

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 87-96 ◽  
Author(s):  
A. H. McKay ◽  
H. Förster ◽  
J. E. Adaskaveg
Keyword(s):  
Mycelial Growth ◽  
Single Spore ◽  
Ph Values ◽  
Highly Active ◽  
Green Mold ◽  
Dmi Fungicides ◽  
Ph Range ◽  
Penicillium Spp ◽  
Twofold Decrease

A diverse collection of isolates of Galactomyces citri-aurantii and G. geotrichum, the causal pathogens of sour rots of citrus and other fruit crops, respectively, was evaluated for sensitivity to demethylation-inhibiting (DMI) fungicides of the triazole group. Propiconazole was found to be highly effective in reducing mycelial growth of both species in vitro. For 139 isolates of G. citri-aurantii, a mean effective concentration for 50% reduction of mycelial growth (EC50 value) of 0.34 μg/ml was determined; whereas, for 33 isolates of G. geotrichum, this value was 0.14 μg/ml. In a comparison of additional DMI fungicides, mean EC50 values for 60 isolates of G. citri-aurantii and 20 isolates of G. geotrichum, were 0.27 and 0.17 μg/ml for cyproconazole, 0.25 and 0.14 μg/ml for metconazole, and 1.16 and 0.73 μg/ml for tebuconazole, respectively. Propiconazole was also highly active against mycelial growth of imazalil-sensitive isolates of Penicillium digitatum, the pathogen that causes green mold of citrus, with a mean EC50 value of 0.008 μg/ml for 63 isolates. Imazalil-resistant isolates of this fungus were cross-resistant to propiconazole. When G. citri-aurantii and P. digitatum were grown at selected pH values between 3 and 9, inhibition by propiconazole occurred over the entire pH range. The fungicide was most effective at pH 5 when compared with the non-fungicide-amended control grown at the same pH. In laboratory mass platings of single-spore isolates sensitive to propiconazole onto selective media, isolates with an up to 81.6-fold decrease in sensitivity to the fungicide were recovered for P. digitatum. For G. geotrichum, isolates with an approximately twofold decrease in sensitivity were obtained. No isolates with reduced sensitivity were recovered for G. citri-aurantii. Propiconazole is currently being registered for postharvest use on citrus and other crops, and the information provided will be valuable in monitoring of fungicide resistance and in designing effective fungicide application strategies.

Effect of Buffer and pH on the Protein Extraction for Chicken Meat

2013 ◽  
Vol 795 ◽  
pp. 206-210
Author(s):  
M.K. Nahar ◽  
Z. Zakaria ◽  
U. Hashim
Keyword(s):  
Protein Extraction ◽  
Chicken Meat ◽  
Anova Analysis ◽  
Citrate Buffer ◽  
Ph Values ◽  
Glycine Buffer ◽  
Significant Difference ◽  
Effects Of Ph ◽  
Ph Range ◽  
Protein Extractability

The study was undertaken to determine the extraction of proteins from chicken meat. The effect of buffer (phosphate, citrate and glycine) and four pH values (6.0, 7.0, 8.0 and 9.0) were investigated. The protein extractability of phosphate, citrate and glycine buffer with in the pH range (pH 6.0 to 9.0) was assessed to determine the best protein extractant for chicken meat. The maximum protein extractabilities at pH 8.0 for phosphate and citrate buffer, and at pH 9.0 for glycine buffer were observed. ANOVA analysis showed that there was no significant difference in protein extractabilities for citrate from phosphate and glycine buffer. Whereas, a significant difference was observed for phosphate buffer from glycine. However, no significant effects of pH were observed.

THE EFFECTS OF pH AND CALCIUM ON THE UPTAKE OF RADIOPHOSPHORUS BY FLUE-CURED TOBACCO

1964 ◽  
Vol 44 (1) ◽  
pp. 28-31 ◽  
Author(s):  
E. T. McEvoy
Keyword(s):  
Nutrient Solution ◽  
Culture Solution ◽  
Ph Values ◽  
Hydroxyl Ion ◽  
Effects Of Ph ◽  
Growth Differences ◽  
Ph Range ◽  
Region Growth ◽  
Complete Nutrient Solution ◽  
Acid Region

The uptake of radiophosphorus by flue-cured tobacco as a function of pH of the culture solution was determined at five different pH values from 4 to 8. When the plants were cultured in a complete nutrient solution containing 240 p.p.m. calcium, P32 uptake increased significantly from pH 4 to a maximum value at pH 5, then decreased with increasing pH to a minimum value of pH 8. At pH values above 5, precipitation occurred as phosphates of calcium, making phosphorus less available to the plant. A reduction in the concentration of calcium in the nutrient solution to 80 p.p.m. and 0, respectively, resulted in a decrease in the amount of phosphorus precipitated and an increase in the P32 uptake at pH 6 to 8. In calcium-free culture solutions, P32 uptake was inhibited by hydrogen ion in the acid region of the pH range and by hydroxyl ion in the alkaline region. Growth differences were not related to variation in P32 uptake.

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