The dynamics of sulfur, phosphorus and iron in flooded soils as affected by changes in Eh and pH

Soil Research ◽  
1993 ◽  
Vol 31 (4) ◽  
pp. 493 ◽  
Author(s):  
RDB Lefroy ◽  
SSR Samosir ◽  
GJ Blair
Keyword(s):  
Soil Solution ◽  
Sorption Capacity ◽  
Podzolic Soil ◽  
Ph Effect ◽  
Low Ph ◽  
Flooded Soils ◽  
Effect Of Ph ◽  
High Ph ◽  
Prairie Soil ◽  
Four Levels

The dynamics of Fe, P and S were studied in three soils (prairie, podzolic and krasnozem) with varying S sorption capacity (13, 32 and 132 �g S sorbed g soil-1 at 5 �g S mL-1). The soils were incubated as suspensions for 14 days at 25�C and the pH and Eh adjusted independently to four levels in the range of pH 4-8-70 and Eh from + 350 to -150 mV. In the prairie and krasnozem soils, the concentration of S in the soil solution at high pH increased as Eh was lowered to +200 mV and then decreased as Eh was lowered further. At low pH, Eh changes did not affect the concentration of S in the soil solution. The changes in the concentration of sorbed S extracted by KH2PO4 were generally similar to those for S in the soil solution. Sulfate sorption increased with a decrease in pH, with the pH effect being greater at higher Eh. At high pH and Eh, the soils released S into the solution but sulfate sorption capacity increased when Eh was lowered. At low pH, the sulfate sorption capacity of the prairie soil first increased with a lowering in Eh from +350 to about +200 mV, but then decreased with a further lowering of Eh. In the krasnozem soil, sulfate sorption capacity increased with a lowering in Eh from the highest (+350 mV) to the lowest (-150 mV) level only at the lowest pH (4.8). In the podzolic soil, the effect of pH on sulfate sorption capacity was similar at all Eh levels. The Eh effects on sulfate sorption capacity of the three soils were different.

Expression patterns of two carbonic anhydrase genes, Na+/K+-ATPase and V-type H+-ATPase, in the freshwater crayfish, Cherax quadricarinatus, exposed to low pH and high pH

2017 ◽  
Vol 65 (1) ◽  
pp. 50 ◽  
Author(s):  
Muhammad Yousuf Ali ◽  
Ana Pavasovic ◽  
Peter B. Mather ◽  
Peter J. Prentis
Keyword(s):  
Carbonic Anhydrase ◽  
Expression Patterns ◽  
Maximum Level ◽  
Low Ph ◽  
Freshwater Crayfish ◽  
Α Subunit ◽  
Cherax Quadricarinatus ◽  
High Ph ◽  
Internal Ph ◽  
Ph Conditions

Carbonic anhydrase (CA), Na+/K+-ATPase (NKA) and Vacuolar-type H+-ATPase (HAT) play vital roles in osmoregulation and pH balance in decapod crustaceans. As variable pH levels have a significant impact on the physiology of crustaceans, it is crucial to understand the mechanisms by which an animal maintains its internal pH. We examined expression patterns of cytoplasmic (CAc) and membrane-associated form (CAg) of CA, NKA α subunit and HAT subunit a in gills of freshwater crayfish, Cherax quadricarinatus, at three pH levels – 6.2, 7.2 (control) and 8.2 – over 24 h. Expression levels of CAc were significantly increased at low pH and decreased at high pH conditions 24 h after transfer. Expression increased at low pH after 12 h, and reached its maximum level by 24 h. CAg showed a significant increase in expression at 6 h after transfer at low pH. Expression of NKA significantly increased at 6 h after transfer to pH 6.2 and remained elevated for up to 24 h. Expression for HAT and NKA showed similar patterns, where expression significantly increased 6 h after transfer to low pH and remained significantly elevated throughout the experiment. Overall, CAc, CAg, NKA and HAT gene expression is induced at low pH conditions in freshwater crayfish.

EFFECTS OF ALUMINIUM ON THE ADVENTITIOUS ROOT SYSTEM, AERIAL BIOMASS AND GRAIN YIELD OF MAIZE GROWN IN THE FIELD AND IN A RHIZOTRON

2006 ◽  
Vol 42 (3) ◽  
pp. 351-366 ◽  
Author(s):  
J. J. COMIN ◽  
J. BARLOY ◽  
V. HALLAIRE ◽  
F. ZANETTE ◽  
P. R. M. MILLER
Keyword(s):  
Grain Yield ◽  
Root System ◽  
Soil Solution ◽  
Root Length ◽  
Adventitious Root ◽  
Adventitious Roots ◽  
Total Root Length ◽  
Al Tolerance ◽  
Root Branching ◽  
Four Levels

The aim of this work was to study the effects of soluble aluminium on the morphology and growth of the adventitious root system, aerial biomass and grain yield of maize (Zea mays). The analysis focuses on two hybrid cultivars (Al-sensitive HS7777 and Al-tolerant C525M). Experiments were carried out in the field and in a rhizotron in Curitiba, Paraná, Brazil. In the field, four levels of lime application were used: T0 = 0 t ha−1, T1 = 3.5 t ha−1, T2 = 7.0 t ha−1, and T3 = 10.5 t ha−1. Two levels were used in a rhizotron: T0 and T3. In the surface horizon (0–15 cm), the Al concentrations of the soil solution were: T0 = 15, T1 = 5.1, T2 = 4.4, and T3 = 3.1 μM. In the field, neither Al concentration in the soil solution nor cultivar affected the number of primary adventitious roots per internode or the total number of primary adventitious roots. However, root diameter, plant population and grain yield of the two cultivars confirmed the differences in Al tolerance between them. Al was observed to have an adverse effect on the grain yield from C525M, while low yields from HS7777, at all levels of Al, precluded any response to liming. In the rhizotron studies, Al concentration and cultivar affected the root branching and total root length. Cultivar C525M had more branches and total root length than HS7777, mainly at low concentrations of soil Al solution, leading to greater spatial colonization of the soil down to 0.9 m depth.

scholarly journals A method for the preparation of low-pH dodecyl sulphate/polyacrylamide-gradient gels

1981 ◽  
Vol 193 (3) ◽  
pp. 1013-1015 ◽  
Author(s):  
G D Jones ◽  
M T Wilson ◽  
V M Darley-Usmar
Keyword(s):  
Cytochrome Oxidase ◽  
Low Ph ◽  
High Ph ◽  
Gel System

1. A low-pH lithium dodecyl sulphate/polyacrylamide-gradient slab-gel system, suitable for electrophoresis, is described, and the migration properties of standard proteins are compared on this and conventional high-pH gels. 2. Cytochrome oxidase may be partially resolved into its component polypeptides. The order of migration of these is, however, dependent on the pH of the gel system.

Effect of pH on the adsorption of phosphate and potassium in batch and in column experiments

Soil Research ◽  
1988 ◽  
Vol 26 (1) ◽  
pp. 165 ◽  
Author(s):  
NS Bolan ◽  
JK Syers ◽  
RW Tillman
Keyword(s):  
Soil Solution ◽  
Opposite Effect ◽  
Column Experiment ◽  
Batch Experiment ◽  
Column Experiments ◽  
Effect Of Ph ◽  
The Difference

The effect of increasing pH, through incubation with Ca(OH)2 and NaOH, on the adsorption of phosphate (P) and potassium (K) was examined in batch and in column experiments. In column experiments, an increase in pH from 5.2 to 8.2 decreased the adsorption of P and increased that of K which resulted in an increased leaching of P and a decreased leaching of K. In a batch experiment, however, an increase in pH resulting from incubation with NaOH gave similar results to those of the column experiment, whereas an increase in pH due to Ca(OH)2 addition caused the opposite effect on the adsorption of both P and K. The difference between the batch and the column experiments in the effect of incubating soil with Ca(OH)2 on the adsorption of P and K is related to the concentration of Ca in the soil solution.

Rhizosphere populations of Rhizobium strains and nodulation of Leucaena leucocephala

1982 ◽  
Vol 22 (117) ◽  
pp. 293 ◽  
Author(s):  
HVA Bushby
Keyword(s):  
Nitrogen Fixation ◽  
Sandy Soil ◽  
Leucaena Leucocephala ◽  
Field Experiments ◽  
Podzolic Soil ◽  
Population Level ◽  
Nodule Formation ◽  
Seed Inoculation ◽  
Rhizobium Strains ◽  
Prairie Soil

Populations of two Rhizobium strains (NGR8 and CB81) in the rhizosphere of Leucaena leucocephala were estimated in field experiments with varying levels of antibiotically marked strains as seed inoculation treatments. The population level varied with soil type and strain of Rhizobium. Multiplication in the rhizosphere was very slow in a prairie soil but was more rapid in a sandy podzolic soil and nodulation was three weeks earlier in the sandy soil than in the prairie soil. Survival of these two strains in soil stored in the laboratory also suggested that they (especially NGR8) were not well suited to the prairie soil. Nodule representation of strain CB81 on the prairie soil decreased from 100% three months after sowing to between 12% and 16% two years after sowing. The results suggest that on this soil indigenous rhizobia form effective nitrogen fixing associations with Leucaena leucocephala and that any improvement in nitrogen fixation will require strains of Rhizobium that are more effective than the indigenous strains and better competitors for nodule formation.

Enhanced performance of air-cathode two-chamber microbial fuel cells with high-pH anode and low-pH cathode

2010 ◽  
Vol 101 (10) ◽  
pp. 3514-3519 ◽  
Author(s):  
Li Zhuang ◽  
Shungui Zhou ◽  
Yongtao Li ◽  
Yong Yuan
Keyword(s):  
Fuel Cells ◽  
Microbial Fuel Cells ◽  
Low Ph ◽  
Air Cathode ◽  
High Ph

scholarly journals The pH-based ecological coherence of active canonical methanotrophs in paddy soils

2020 ◽  
Vol 17 (6) ◽  
pp. 1451-1462 ◽  
Author(s):  
Jun Zhao ◽  
Yuanfeng Cai ◽  
Zhongjun Jia
Keyword(s):  
Soil Ph ◽  
Rice Paddy ◽  
Low Ph ◽  
Paddy Soils ◽  
Paddy Fields ◽  
Type I ◽  
Type Ii ◽  
High Ph ◽  
Niche Specialization ◽  
Rice Paddy Soils

Abstract. Soil pH is considered one of the main determinants of the assembly of globally distributed microorganisms that catalyze the biogeochemical cycles of carbon (C) and nitrogen (N). However, direct evidence for niche specialization of microorganisms in association with soil pH is still lacking. Using methane-oxidizing bacteria (methanotrophs) as a model system of C cycling, we show that pH is potentially the key driving force selecting for canonical γ (type I) and α (type II) methanotrophs in rice paddy soils. DNA-based stable isotope probing (DNA-SIP) was combined with high-throughput sequencing to reveal the taxonomic identities of active methanotrophs in physiochemically contrasting soils from six different paddy fields across China. Following microcosm incubation amended with 13CH4, methane was primarily consumed by Methylocystis-affiliated type II methanotrophs in soils with a relatively low pH (5.44–6.10), whereas Methylobacter- or Methylosarcina-affiliated type I methanotrophs dominated methane consumption in soils with a high pH (7.02–8.02). Consumption of 13CH4 contributed 0.203 % to 1.25 % of soil organic C, but no significant difference was observed between high-pH and low-pH soils. The fertilization of ammonium nitrate resulted in no significant changes in the compositions of 13C-labeled methanotrophs in the soils, although significant inhibition of methane oxidation activity was consistently observed in low-pH soils. Mantel analysis further validated that soil pH, rather than other parameters tested, had significant correlation to the variation in active methanotrophic compositions across different rice paddy soils. These results suggest that soil pH might have played a pivotal role in mediating the niche differentiation of ecologically important aerobic methanotrophs in terrestrial ecosystems and imply the importance of such niche specialization in regulating methane emissions in paddy fields following increasingly intensified input of anthropogenic N fertilizers.

Growth of Listeria monocytogenes on Vacuum-packaged Beef

1990 ◽  
Vol 53 (9) ◽  
pp. 739-741 ◽  
Author(s):  
FREDERICK H. GRAU ◽  
PAUL B. VANDERLINDE
Keyword(s):  
Listeria Monocytogenes ◽  
Low Ph ◽  
Tissue Growth ◽  
Initial Population ◽  
Fatty Tissue ◽  
High Ph ◽  
Packaged Beef

Pieces of beef striploin (400 g) were inoculated with Listeria monocytogenes strain Murray B, vacuum packaged, and stored at either 0°C or 5.3°C. Growth of the organism on the beef depended on the temperature of storage, the pH of the lean, and the type of tissue. Growth was more rapid at 5.3°C than at 0°C, and faster on striploins of high pH (6.0–6.1) than on striploins of low pH (5.5–5.7). During storage, the population of L. monocytogenes was higher on fatty tissue than on lean principally because growth occurred earlier on the fat. When low pH striploins were held at 5.3°C, listeria grew from an initial count of 2–5×103 CFU/cm2 to 3×107 CFU/cm2 in 16 d on the fat, and in 20 d, to 106 CFU/cm2 on the lean and to 5×107 CFU/ml in the purge fluid. After storage at 0°C for 76 d, the populations reached were 106 CFU/cm2 on the fat, 104 CFU/cm2 on the lean, and 3×105 CFU/ml in the purge fluid. When high pH striploins were held at 0°C for 10 weeks, listeria grew from an initial population of 150–400 CFU/cm2 to just over 106 CFU/cm2 on the fat, 2×105 CFU/cm2 on the lean, and 4×106 CFU/ml in purge fluid.

Comparing metal leaching and toxicity from high pH, low pH, and high ammonia fly ash

Fuel ◽  
2007 ◽  
Vol 86 (10-11) ◽  
pp. 1623-1630 ◽  
Author(s):  
Anthony V. Palumbo ◽  
Jana R. Tarver ◽  
Lisa A. Fagan ◽  
Meghan S. McNeilly ◽  
Rose Ruther ◽  
...  
Keyword(s):  
Fly Ash ◽  
Low Ph ◽  
Metal Leaching ◽  
High Ph ◽  
High Ammonia

Effect of pH on metabolism of alpha-ketoglutarate by renal cortical mitochondria

1981 ◽  
Vol 240 (2) ◽  
pp. F120-F126 ◽  
Author(s):  
R. L. Tannen ◽  
A. S. Kunin
Keyword(s):  
Low Ph ◽  
Alkaline Ph ◽  
Glutamine Concentration ◽  
Acid Base ◽  
Experimental Conditions ◽  
Effect Of Ph ◽  
Adaptive Changes ◽  
Overall Response ◽  
Per Se ◽  
The Difference

The effect of acid-base perturbations on mitochondrial alpha-ketoglutarate (alpha-KG) metabolism was quantitated by measuring the nitrogen and carbon metabolites of glutamine. alpha-KG metabolized was calculated as the difference between alpha-KG production from glutamine (glutamate deamination plus transamination) and alpha-KG accumulation in the medium. Under all experimental conditions accumulation in the medium of malate plus aspartate was altered similarly to the calculated change in alpha-KG metabolism. Mitochondria from rats with chronic acidosis were compared to pair-fed controls. Chronic acidosis resulted in increased alpha-KG production and its intramitochondrial concentration; the rate of conversion of alpha-KG to succinate was unchanged. When mitochondria from normal animals were incubated at pH 7.0, 7.4, and 7.7, the amount of alpha-KG metabolized was altered, but the magnitude and direction of the response was dependent on the concentration of glutamine (0.5, 1.0, or 5.0 mM). A low pH depressed production but stimulated the subsequent metabolism of alpha-KG, whereas an alkaline pH acted in the opposite fashion. The overall response at a given glutamine concentration depended on which effect predominated. Accordingly, chronic acidosis does not induce adaptive changes, but pH, per se, directly alters intramitochondrial alpha-KG metabolism.

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