The effect of solution pH and external calcium concentration on the early growth and nodulation of several annual Medicago species

1990 ◽  
Vol 41 (5) ◽  
pp. 933 ◽  
Author(s):  
MA Ewing ◽  
AD Robson
Keyword(s):  
Calcium Concentration ◽  
Acid Soils ◽  
Early Growth ◽  
Low Ph ◽  
Solution Ph ◽  
Nodule Number ◽  
Low Calcium ◽  
Wide Range ◽  
Effects Of Ph ◽  
Annual Medics

The study tested the hypothesis that annual medic species which nodulate well in acid soils in the field (M. murex Willd. and M. polymorpha L.) will nodulate better in acid solutions with low calcium concentrations than annual medics which nodulate poorly in acid soils (M, truncatula Gaertn.). Effects of pH (5.5 and 6.5) and calcium concentration (0.2, 0.5, 1 and 2 mM) on the early growth and nodulation of three annual medic species (M. truncatula, M. polymorpha and M. murex) were investigated. Increasing pH or calcium concentration did not increase plant growth for any of the species. However, nodulation was generally depressed by low pH for all species. Increasing calcium concentration in solution increased nodulation in all species. Effects of low pH and low calcium concentration in decreasing nodule number were much greater for M. truncatula than for M. polymorpha and M. murex. At pH 5.5, M. truncatula failed to nodulate at any calcium concentration, whereas a large proportion of M. murex plants nodulated at 1 mM calcium and some M. polymorpha plants nodulated at 2 mM calcium. At pH 6.5, M. polymorpha required 1 mM calcium in solution for maximum nodule number, and M. murex only 0.5 mM calcium, whereas nodule number for M. truncatula increased up to 2 mM calcium, the highest concentration used. The results provide the basis for a simple screening system to distinguish differences among annual medics in nodulation tolerance to acidity. The maintenance of ranking among species with respect to nodulation over a wide range of stresses induced by combinations of low pH and calcium concentration suggest that screening using a single stress combining these two components would be adequate. Nodulation differences between species can be simply and effectively assessed using a scoring system combining number size and location of nodules.

Effect of solution pH, external calcium concentration, and aluminium activity on nodulation and early growth of cowpea

1990 ◽  
Vol 41 (2) ◽  
pp. 359 ◽  
Author(s):  
AK Alva ◽  
CJ Asher ◽  
DG Edwards
Keyword(s):  
Plant Growth ◽  
Host Plant ◽  
Acid Tolerance ◽  
Dry Weight ◽  
Low Ph ◽  
Concentration Effects ◽  
Solution Ph ◽  
Nodule Number ◽  
Effects Of Ph ◽  
Nutrient Solutions

Effects of pH, calcium (Ca), and aluminium (Al) on the growth and nodulation of cowpea (Vigna unguiculata) were studied in large-volume, dilute nutrient solutions. Ca concentrations over the range 0.05 mM to 2.5 mM, and pH over the range 4.5 to 5.5, had no significant effect on the growth of the host plant. However, the combination of low pH and low Ca delayed nodulation and strongly depressed nodule number and nodule dry weight. At the highest Ca concentration, effects of pH on nodule number were small and not significant, and effects on nodule weight, although significant, were much smaller than at the lowest Ca concentration. It was concluded that nodulation was more sensitive to low Ca and low pH than was host plant growth. At pH 4.5 and 0.5 mM Ca, A1 delayed and depressed nodulation. An activity of 12.7 8M Al delayed nodulation by four days, and reduced nodule number and nodule dry weight drastically. At higher Al activities, nodulation was reduced to zero. The critical Al activities (10% reduction) were approx. 0.3 and 0.5 ,8M for nodule number and nodule dry weight. The dry weight of tops and roots showed a roughly linear decrease with increasing Al activity over the range 0 to 8 8M, both in inoculated plants supplied with 'starter nitrogen' and in plants supplied continuously with adequate mineral nitrogen. Critical A1 activities for growth were in the range of 4 to 8 PM. It was concluded that nodulation was much more sensitive to Al than was host plant growth. The results are discussed in relation to recent literature on the acid tolerance of cowpea.

scholarly journals Distribution and abundance of benthic macroinvertebrates and zooplankton in lakes in Kejimkujik National Park and National Historic Site of Canada, Nova Scotia

2014 ◽  
Vol 128 (1) ◽  
pp. 1 ◽  
Author(s):  
Christina Nussbaumer ◽  
Neil M. Burgess ◽  
Russ C. Weeber
Keyword(s):  
Nova Scotia ◽  
National Park ◽  
Calcium Concentration ◽  
Low Ph ◽  
Historic Site ◽  
Aquatic Biodiversity ◽  
Low Calcium ◽  
Wide Range ◽  
Acid Tolerant ◽  
Kejimkujik National Park

As part of the Acid Rain Biomonitoring Program at Environment Canada, we sampled aquatic biodiversity in 20 acidic lakes in 2009 and 2010 in Kejimkujik National Park and National Historic Site of Canada and vicinity in Nova Scotia. We established an inventory of current aquatic macroinvertebrate and zooplankton species composition and abundance in each of the 20 study lakes. A total of 197 macroinvertebrate taxa were identified; the number of taxa observed was positively correlated with pH across the 20 lakes. Acid-tolerant taxa, such as isopods, amphipods, trichopterans, and oligochaetes, were common and abundant, while bivalves, gastropods, and leeches were lower in abundance. The number of isopods and amphipods collected was correlated with calcium concentration; a greater proportion of isopods than amphipods were collected from lakes with low calcium and low pH. Taxa with hard, calcareous shells, such as bivalves and gastropods, were not present in lakes with low calcium and low pH, with bivalves occurring only in lakes above pH 4.9. Odonates and ephemeropterans, which were low in abundance, were associated with a wide range of acidity. Coleopteran abundance was positively correlated with concentrations of dissolved organic carbon. A total of 26 zooplankton taxa were collected, but only cyclopoid abundance was correlated with lake pH. Results presented here provide a summary of aquatic biodiversity in lakes in Kejimkujik National Park and National Historic Site and vicinity and provide a baseline for future monitoring as acid deposition continues to affect this acid-sensitive region in Atlantic Canada.

scholarly journals The Effects of pH on the Labellar Sugar Receptor of the Fleshfly

1969 ◽  
Vol 53 (4) ◽  
pp. 450-470 ◽  
Author(s):  
Akio Shiraishi ◽  
Hiromichi Morita
Keyword(s):  
Receptor Site ◽  
Low Ph ◽  
The Other ◽  
High Ph ◽  
Sugar Receptor ◽  
Other Hand ◽  
Wide Range ◽  
Effects Of Ph ◽  
Ionizable Groups ◽  
Inhibition Curve

Reproducible results describing the effects of pH on the response of the labellar sugar receptor of the fleshfly, Boettcherisca peregrina, were obtained. The response to sucrose was independent over a wide range of pH (3.0 to 10.0 for sucrose stimulation), but was inhibited fairly sharply on both sides of this range. Similar results were obtained for monosaccharide stimulation. The receptor was excited on stimulation by water above pH 12.0. The effects of high pH, both inhibitory and excitatory, were affected by the presence of salts. In the presence of 0.5 molar NaCl, for example, the pH-inhibition curve was shifted toward lower pH's by about one pH unit. The effects of low pH, on the other hand, were not affected by salts. Following Dixon's theory, it was concluded that at least five ionizable groups (loosing positive charges above pH 10.5) were located at the receptor site.

Response of sweet potato cultivars to acid soil infertility factors. I. Effects of solution pH on early growth

2000 ◽  
Vol 51 (1) ◽  
pp. 23 ◽  
Author(s):  
V. P. Ila'ava ◽  
C. J. Asher ◽  
F. P. C. Blamey
Keyword(s):  
Root Growth ◽  
Sweet Potato ◽  
Ipomoea Batatas ◽  
Acid Soil ◽  
Chemical Properties ◽  
Early Growth ◽  
Low Ph ◽  
Potato Cultivars ◽  
Stem Cuttings ◽  
Solution Ph

Sweet potato [Ipomoea batatas (L.) Lam.] is cultivated on soils varying widely in chemical properties, but relatively little is known about the effects of pH on the growth of this crop. In commercial and subsistence agriculture, sweet potato is propagated mostly from stem cuttings. This paper reports effects of a range of pH treatments (3.5–8.0) in flowing solution culture on early growth from cuttings of 15 sweet potato cultivars. Root growth was either greatly reduced or inhibited at pH 3.5. Increasing the pH to 4.0 markedly increased root development. Further increases in solution pH from 4.0 to 8.0 did not appear to affect root growth in most cultivars. Top growth in most cultivars showed a tendency to increase when pH was increased from 3.5 to 5.5 before declining with further increases in solution pH. The sweet potato cultivars studied differed widely in their tolerance to low pH, producing 16–48% of maximum top dry mass at pH 3.5. Tissue analysis from selected cultivars showed that K and Ca appeared to be limiting at pH 3.5, while P may have been deficient at pH 8.0. Results of this study indicate that low pH per se does not appear to be a major factor responsible for poor sweet potato yields in acid soils.

Ambient pH and Calcium Concentration as Modifiers of Growth and Calcium Dynamics of Brook Trout, Salvelinus fontinalis

1984 ◽  
Vol 41 (12) ◽  
pp. 1774-1780 ◽  
Author(s):  
David W. Rodgers
Keyword(s):  
Brook Trout ◽  
Calcium Concentration ◽  
Salvelinus Fontinalis ◽  
Axial Skeleton ◽  
Low Ph ◽  
Fish Growth ◽  
Calcium Dynamics ◽  
Experimental Fish ◽  
Low Calcium ◽  
High Calcium

Juvenile brook trout, Salvelinus fontinalis, were maintained in water of pH 5.3 or 6.5 and calcium concentrations of 5 or 40 mg/L to determine the effects of these factors on fish growth and calcium dynamics. Growth rates varied more than twofold and were significantly reduced by both low ambient calcium concentration and low pH. In contrast, calcium dynamics of the fish were significantly affected by calcium concentration but not pH. Brook trout in low-calcium water retained less labeled dietary calcium and deposited less labeled calcium in axial skeleton and visceral tissues than fish in high-calcium water. Calcium concentrations of the skin and fins were slightly but significantly reduced among fish in low-calcium water, but neither pH nor ambient calcium concentration significantly affected ash content or calcium concentration of axial skeleton and visceral tissues of experimental fish.

scholarly journals Effects of pH and Trace Minerals on Long-Term Starvation of Leuconostoc mesenteroides

2000 ◽  
Vol 66 (3) ◽  
pp. 976-981 ◽  
Author(s):  
Dong-Shik Kim ◽  
Steven Thomas ◽  
H. Scott Fogler
Keyword(s):  
Cell Viability ◽  
Decay Rate ◽  
Leuconostoc Mesenteroides ◽  
Trace Minerals ◽  
Solution Ph ◽  
Decay Rate Constant ◽  
Ph Values ◽  
Wide Range ◽  
Effects Of Ph ◽  
Starvation Conditions

ABSTRACT Laboratory experiments have definitively shown that exopolymer-producing bacteria have the potential to modify the flow of fluids in oil reservoirs to enhance oil production. Once injected into the reservoir, they will be subjected to a wide range of pH values and to starvation resulting from nutrient depletion. For successful field implementation it is necessary to have a fundamental understanding of these effects on the viability of bacteria. This paper addresses the effects of pH and trace minerals on cell viability of Leuconostoc mesenteroides during carbon source depletion. Two different carbon sources were used to grow cells before transferring the cells to starvation conditions: sucrose and a combination of glucose and fructose. These substrates were chosen because L. mesenteroides produces a significant amount of water-insoluble exopolymers (dextran) under sucrose-fed conditions, which may enhance cell survival under harsh conditions. The effects of dextran on the cell viability were tested at different pH values with and without trace minerals. The rate of cell death followed an exponential-decay law for different values of the solution pH. The optimal solution pH for survival was pH 5, whereas cells died rapidly at pH 3 and below and at pH 13 and above. The sucrose-fed cells showed a greater viability than cells fed glucose and fructose for all pH ranges tested. The results indicated that water-insoluble exopolymers help cells survive for longer periods of time under starvation conditions. The effects of trace minerals on cell culturability were tested at two pH values, 4.5 and 7. For both cases, cells showed a greater culturability (smaller decay rate constant) in the presence of trace minerals than without trace minerals. It was also found that the effects of trace minerals on cell culturability were greater for glucose-fructose-fed cells than for sucrose-fed cells. The Michaelis pH function theory was used for comparing the relationships between the cell decay rate and pH.

The effect of nitrogen supply on the early growth and nodulation of several annual Medicago species

1990 ◽  
Vol 41 (3) ◽  
pp. 489 ◽  
Author(s):  
MA Ewing ◽  
AD Robson
Keyword(s):  
Inorganic Nitrogen ◽  
Acid Soils ◽  
Early Growth ◽  
Solution Culture ◽  
Nitrogen Supply ◽  
Fixed Nitrogen ◽  
Nodule Number ◽  
Annual Medicago ◽  
Medicago Species ◽  
Nutrient Solutions

Differences in nodulation amongst species of annual Medicago (medics) on moderately acid soils could be explained by differences in response to the form or level of nitrogen supply. We compared the growth and bulk soil pH changes when four annual medic species (M. truncatula, M. littoralis, M. polymorpha and M. murex) were supplied with ammonium, nitrate or biologically fixed nitrogen. Growth and nodule number were measured for M. polymorpha grown in solution culture at constant nitrogen supply (1 mM) but variable ammonium to nitrate ratio (1:0, 3:1, 1:1, 1:3, 0:1). Similar measurements were also made on M. truncatula, M. polymorpha and M. murex exposed to different concentrations of nitrate (0, 0.1, 1.5, 10 mM) during nodulation. When uninoculated, all medic species grew at the same rate when given equivalent levels of inorganic nitrogen as either ammonium or nitrate. All species similarly decreased the pH of soil around their roots when supplied with ammonium, and increased pH when supplied with nitrate. Nutrient solutions were acidified when M. polymorpha was supplied with ammonium and neutralized when nitrate was supplied. However, when ammonium and nitrate were added simultaneously solutions acidified, indicating a more rapid uptake of ammonium than nitrate. Nodule number of all medic species was reduced by nitrate concentrations in solution as low as 0.1 mM. M. truncatula formed fewer nodules than M. polymorpha and M. murex at all concentrations of nitrate.

Effects of pH on excitation and contraction in frog twitch muscle

1977 ◽  
Vol 55 (3) ◽  
pp. 709-723 ◽  
Author(s):  
J. G. Foulks ◽  
Florence A. Perry
Keyword(s):  
Membrane Potential ◽  
Action Potentials ◽  
Time Course ◽  
Calcium Concentration ◽  
Divalent Cations ◽  
Ion Concentration ◽  
Resting Potential ◽  
Hydrogen Ion Concentration ◽  
Wide Range ◽  
Effects Of Ph

The electrical and mechanical behaviour of frog twitch muscle in response to changes in membrane potential has been examined over a wide range of hydrogen ion concentration (pH 3.0–11.0). The changes in resting and action potentials, twitches, and maximum potassium-induced contractures (K contractures) were remarkably small when the pH was varied between 5.0 and 10.0. The time course of action potentials generally displayed small graded changes with variation in pH, possibly as the result of changes in surface potential.The amplitude of twitches and maximum K contractures was substantially decreased when pH was reduced to 4.0 or raised to 11.0 without significant alteration in membrane resting potential or consistent suppression of excitation, but maximum caffeine-induced contractures were unchanged. Replacement of chloride with perchlorate promptly antagonized the depressant effects of pH extremes (4.0, 11.0) on both twitch amplitude and maximum K-contracture tension. Acid-induced reductions in maximum K-contracture tension also were partially antagonized by increased calcium concentration. The onset and recovery from the contraction-depressant effects of pH extremes were too slow to be explained by the titration of groups immediately accessible at the membrane surface but too rapid to be accounted for by changes in intracellular pH. Thus, excitation and contraction apparently were uncoupled by sufficient alteration in extracellular pH. Changes in external pH had little effect on the impairment of maximum K contractures by media lacking divalent cations, or on the restoration of such responses by perchlorate except at very alkaline pH (10.0–11.0).The threshold for K contractures was reduced at pH 11.0, but otherwise was little affected by variation in pH at normal concentrations of divalent cations. Altered pH did not modify the usual effects of increased calcium concentration on the relation between potassium concentration and K-contracture tension. When K contractures were maintained by perchlorate in the absence of divalent cations, hydrogen ions displayed calcium-like actions on the relation between external K concentration ([K]0) and K-contracture tension, and also on the time course of submaximum K contractures. These observations are compatible with similar effects of hydrogen and calcium ions on surface potential.The problem of identifying putative charged groups which might influence the linkage between contractile responses and changes in membrane potential is discussed.

Effect of calcium, pH and nitrogen on the growth and chemical composition of some tropical and temperate pasture legumes. I. Nodulation and growth

1976 ◽  
Vol 27 (5) ◽  
pp. 611 ◽  
Author(s):  
CS Andrew
Keyword(s):  
Dry Matter ◽  
Calcium Sulphate ◽  
Low Ph ◽  
Root Weight ◽  
Calcium Treatment ◽  
Pasture Legumes ◽  
Low Calcium ◽  
High Calcium ◽  
Effects Of Ph ◽  
Ph Range

The effects of a factorial combination of calcium (0.125, 2.0 mM calcium sulphate), pH (4.0, 4.5, 5.0, 6.0) and nitrogen (nil, 2.0mM ammonium nitrate) on the nodulation and growth of some tropical and temperate pasture legumes were determined. Macroptilium lathyroides and Lotononis bainesii were unaffected by low pH and low calcium (100% of plants nodulated at all treatments). In Stylosanthes humilis, Trifoliurn semipilosum, and T. rueppellianum reduced nodulation occurred only at pH 4.0. Desmodium uncinatum and Trifolium repens were sensitive to low pH, and nodulation was markedly reduced at pH 4.0 and below 5.0 respectively. Medicago sativa, M. truncatula, M. scutellata, and Glycine wightii were extremely sensitive, maximum nodulation occurring only at pH 6-0 and 2 . 0 mM calcium. Furthermore, the dry matter yields of plants that nodulated under inferior treatments were less than those of plants nodulated under optimum treatments. Nodulation and growth were strongly controlled by pH, and although interactions occurred with calcium treatment, these were primarily in the intermediate pH range. Dry matter yields of nodulated plants of S. humilis and L. bainesii were greater at the low calcium sulphate treatment (0.125mM) than at thc high treatment (2.0mM). The remaining legumes gave varying positive responses to the high calcium treatment. Root weight ratios of nodulated plants were decreased by the higher treatments, the minimum occurring at those treatments producing the highest dry matter. In the presence of applied nitrogen (no nodulation), the effects of pH and calcium on dry matter were small, but the trends were similar to those for nodulation and dry matter production of the nodulated plants in the Rhizobium series. Root weight ratios of plants in the nitrogen series were equal to or less than those for the maximum-yielding plants in the nodulation series. It is considered that both nodulation and subsequent plant growth are dominated by the hydrogen ion effect, and that the beneficial effect of calcium operates within certain pH limits. pH had little effect on plants that were well supplied with nitrogen.

Effect of Solution pH and Calcium Concentration on Germination and Early Growth of Groundnut

2003 ◽  
Vol 26 (6) ◽  
pp. 1247-1262 ◽  
Author(s):  
M. R. Murata ◽  
P. S. Hammes ◽  
G. E. Zharare
Keyword(s):  
Calcium Concentration ◽  
Early Growth ◽  
Solution Ph
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