Nodulation and growth of Medicago truncatula on acid soils. II. Colonization of acid soils by Rhizobium meliloti

1970 ◽  
Vol 21 (3) ◽  
pp. 435 ◽  
Author(s):  
AD Robson ◽  
JF Loneragan
Keyword(s):  
Calcium Carbonate ◽  
Medicago Truncatula ◽  
Rhizobium Meliloti ◽  
Acid Soils ◽  
Sandy Soils ◽  
Acid Tolerant ◽  
Second Year ◽  
Annual Medicago ◽  
Medicago Species ◽  
Better Than

Six strains of Rhizobium meliloti varied greatly in their ability to colonize two moderately acid sandy soils (pH 5.0-5.1 in 115 suspension of soil in 0.01M calcium chloride) in the year of sowing inoculated lime-coated seeds of Medicago truncatula. The strains also varied in their ability to nodulate M. truncatula in the year after sowing. With all rhizobial strains and on both soils, calcium carbonate applied in the year of sowing strongly promoted colonization in the year of sowing. It also greatly increased nodulation and growth of M. truncatula in the year after sowing. Apparently calcium carbonate increased second year nodulation by promoting the colonization of the acid soils by R. meliloti in the year of sowing. Differences among strains in second year nodulation appeared to be related to differences in the ability of the strains to colonize the soils in the year of sowing. Strains isolated from moderately acid sandy soils were markedly superior in both properties, and on both soils, to strain SU47 from commercial inoculum, but were generally no better than strain U45 from commercial inoculum. Even the most acid-tolerant strains colonized the acid soils relatively slowly. It is suggested that R. meliloti strains in general have a poor ability to colonize acid soils and that this property is a major factor limiting the growth and persistence of annual Medicago species on acid soils in the field.

Nodulation and growth of Medicago truncatula on acid soils. I. Effect of calcium carbonate and inoculation level on the nodulation of Medicago truncatula on a moderately acid soil

1970 ◽  
Vol 21 (3) ◽  
pp. 427 ◽  
Author(s):  
AD Robson ◽  
JF Loneragan
Keyword(s):  
Calcium Carbonate ◽  
Medicago Truncatula ◽  
Soil Ph ◽  
Soil Acidity ◽  
Rhizobium Meliloti ◽  
Acid Soil ◽  
Acid Soils ◽  
Acid Tolerant ◽  
Annual Medicago ◽  
Medicago Species

On a moderately acid soil (pH 4.6 in 115 suspension of soil in 0.01M calcium chloride), nodulation of Medicago truncatula cv. Cyprus responded markedly to increasing applications of calcium carbonate, which increased soil pH. Since the effect of increasing soil pH on the percentage nodulation could be replaced to a large extent by increasing the inoculation level, it appeared that nodulation was restricted by the inability of Rhizobium meliloti to survive or multiply in the acid soil. The growth of R, meliloti appeared more sensitive to soil acidity than growth of the host plant of annual Medicago species. It is suggested that more acid-tolerant strains of R. meliloti would permit annual Medicago species to be grown successfully on moderately acid soils, thus extending the range of soils suitable for the growth of these species.

Acid tolerance in the Rhizobium meliloti - Medicago symbiosis

1986 ◽  
Vol 37 (1) ◽  
pp. 55 ◽  
Author(s):  
JG Howieson ◽  
MA Ewing
Keyword(s):  
Rhizobium Meliloti ◽  
Acid Soil ◽  
Acid Soils ◽  
Acid Tolerance ◽  
Loamy Sand ◽  
Alkaline Soils ◽  
Regenerative Growth ◽  
Commercial Inoculant ◽  
Acid Tolerant ◽  
Second Year

Several strains of Rhizobium meliloti that originated from acid soils in Sardinia, Italy, were markedly superior in colonizing a moderately acid loamy sand (pH 5.0 in 1:5 0.01 M CaCl2) than two Australian commercial inoculant strains (U45 and CC169), and a group of strains that originated from alkaline soils in Syria and Iraq. Six Medicago hosts also varied greatly in their ability to achieve nodulation in this soil. M. polymorpha and M. murex were far superior in this respect to M. littoralis, M. truncatula and M. tornata. The most acid-tolerant strains of R. meliloti, WSM419 and WSM413, were able to nodulate a high proportion of plants of M. polymorpha and M. murex sown in the second year between 11 and 20 cm from the point of introduction of the rhizobia into the soil the previous year. It is suggested that these more saprophytically competent isolates of R. meliloti, combined with the species of Medicago more able to nodulate readily in acid soil, will extend the range of soils suitable for successful regenerative growth of these species.

Strategies for control of Phoma black stem in annual Medicago species

1989 ◽  
Vol 29 (5) ◽  
pp. 635 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Disease Severity ◽  
Medicago Truncatula ◽  
Field Trial ◽  
Subsequent Development ◽  
Field Site ◽  
Infected Seed ◽  
Annual Medicago ◽  
And Control ◽  
Medicago Species ◽  
Selection Of

Strategies for control of Phoma black stem disease in annual Medicago species through selection of cultivars with increased resistance to Phoma medicaginis, fungicidal spray applications to swards, and fungicidal control of seedborne infection, were investigated. Fiftyseven annual Medicago cultivars and lines were screened for resistance in the field in 1 m rows over 2 consecutive seasons. There were significant differences in resistance among species and also between lines and cultivars of any particular species. Three M. rugosa cultivars were very highly resistant and most cultivars and lines showed some resistance. In a field trial, the fungicides benomyl, carbendazim, flutriafol, propiconazole, thiabendazole and triadimefon were tested for their efficacy in controlling Phoma black stem disease. All fungicides reduced disease severity in the sward and, except for thiabendazole, the percentage burrs with Phoma lesions. The role and control of seed-borne P. medicaginis in causing Phoma black stem disease in Medicago truncatula and M. polymorpha var. brevispina at a field site was also investigated. Seed-borne P. medicaginis caused subsequent development of Phoma black stem disease in swards sown with infected seed. Disease appeared earlier, developed faster and became much more severe in M. truncatula cv. Cyprus than in M. polymorpha cv. Serena. Application of benomyl seed treatments (0.1 and 0.5% w/w) resulted in only a 4-5 week delay in the onset of Phoma black stem symptoms.

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.

Calcium modifies pH effects on the growth of acid-tolerant and acid-sensitive Rhizobium meliloti

1992 ◽  
Vol 43 (3) ◽  
pp. 765 ◽  
Author(s):  
JG Howieson ◽  
AD Robson ◽  
LK Abbott
Keyword(s):  
Soil Acidity ◽  
Rhizobium Meliloti ◽  
Acid Soils ◽  
Defined Medium ◽  
Ph Effects ◽  
Poor Growth ◽  
Growth And Survival ◽  
Ph Values ◽  
Acid Tolerant ◽  
Selection Of

The growth of Rhizobium meliloti is sensitive to soil acidity, and its poor growth and survival limits the production from Medicago spp. on acid soils. In the selection of acid tolerant rhizobia for medics, growth in acidified laboratory media has been poorly related to persistence in acid soils. However, the Ca concentration in laboratory media may have been inadequate for growth of some rhizobial strains at low pH. Therefore, acid-tolerant and acid-sensitive strains of R. meliloti were grown in a buffered, defined medium at a range of Ca and P concentrations, and at several pH values. Growth rate was increased by increasing the Ca concentration from 200 to 2000 8M at low (5-70) and moderate (6.50) pH, but not at pH 7.30. Thus, the Ca requirement for the growth of R. meliloti under acid conditions is much higher than previously thought.

EFFECTS OF SOIL ACIDITY ON RHIZOBIA NUMBERS, NODULATION AND NITROGEN FIXATION BY ALFALFA AND RED CLOVER

1977 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
W. A. RICE ◽  
D. C. PENNEY ◽  
M. NYBORG
Keyword(s):  
Nitrogen Fixation ◽  
Soil Ph ◽  
Soil Acidity ◽  
Field Experiments ◽  
Rhizobium Meliloti ◽  
Acid Soils ◽  
Red Clover ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Greenhouse Experiments

The effects of soil acidity on nitrogen fixation by alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.) were investigated in field experiments at 28 locations, and in greenhouse experiments using soils from these locations. The pH of the soils (limed and unlimed) varied from 4.5 to 7.2. Rhizobia populations in the soil, nodulation, and relative forage yields (yield without N/yield with N) were measured in both the field and greenhouse experiments. Rhizobium meliloti numbers, nodulation scores, and relative yields of alfalfa decreased sharply as the pH of the soils decreased below 6.0. For soils with pH 6.0 or greater, there was very little effect of pH on any of the above factors for alfalfa. Soil pH in the range studied had no effect on nodulation scores and relative yields of red clover. However, R. trifolii numbers were reduced when the pH of the soil was less than 4.9. These results demonstrate that hydrogen ion concentration is an important factor limiting alfalfa growth on acid soils of Alberta and northeastern British Columbia, but it is less important for red clover. This supports the continued use of measurements of soil pH, as well as plant-available Al and Mn for predicting crop response to lime.

scholarly journals Effects of Fe deficiency on the protein profiles and lignin composition of stem tissues from Medicago truncatula in absence or presence of calcium carbonate

2016 ◽  
Vol 140 ◽  
pp. 1-12 ◽  
Author(s):  
Jorge Rodríguez-Celma ◽  
Giuseppe Lattanzio ◽  
Dido Villarroya ◽  
Elain Gutierrez-Carbonell ◽  
Laura Ceballos-Laita ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Medicago Truncatula ◽  
Fe Deficiency ◽  
Protein Profiles ◽  
Lignin Composition
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