The root-nodule bacteria as factors in clover establishment in the red basaltic soils of the Lismore district, NSW. III. Field inoculation trials.

1954 ◽  
Vol 5 (1) ◽  
pp. 77 ◽  
Author(s):  
HV Jenkins ◽  
JM Vincent ◽  
LM Waters
Keyword(s):  
Root Nodule ◽  
Effective Strain ◽  
Fertilizer Treatment ◽  
Nodule Bacterium ◽  
Nodule Bacteria ◽  
Field Inoculation ◽  
Red Soils ◽  
Basaltic Soils ◽  
Successful Inoculation ◽  
Heavy Dose

Field experience with crimson and subterranean clovers grown in the Lismore red soils has confirmed the importance of successful inoculation with an effective strain of a root-nodule bacterium. Strains of rhizobia, applied singly or in a mixture, differed markedly in their ability to form nodules in the red soils. A relatively heavy dose of inoculum (c. 10 times the usual) was desirable. Superphosphate and dolomite were favourable to nodulation but a trace element mixture that included copper sulphate at the rate of 10 lb per acre proved markedly toxic when put in the drill with inoculated seed. Yield was directly related to the proportion of plants effectively nodulated, whether the latter varied because of the nature of the inoculum or because of fertilizer treatment. Results of inoculation at other centres in the district were very satisfactory. Success has also been obtained with the inoculation of Medicago, pea, and vetch.

Competition between effective and ineffective strains of Rhizobium trifolii in the nodulation of Trifolium subterraneum

1969 ◽  
Vol 20 (5) ◽  
pp. 827 ◽  
Author(s):  
AC Robinson
Keyword(s):  
Competitive Ability ◽  
Root Nodule ◽  
Effective Strain ◽  
Substantial Reduction ◽  
Trifolium Subterraneum ◽  
Bacterial Cells ◽  
Rhizobium Trifolii ◽  
Parallel Study ◽  
Nodule Bacteria ◽  
Tube Culture

The competitive ability of effective and ineffective strains of Rhizobium trifolii to form nodules on two cultivars of Trifolium subterraneum was examined under bacteriologically controlled conditions in tube culture. Seedlings were inoculated with mixtures of known numbers each of effective and of ineffective strains and the strains forming the nodules subsequently determined. In all instances, the effective strains formed a much greater proportion of nodules than would be expected from the relative numbers of each strain in the inoculum. Moreover, a reduction in the numbers of an effective strain relative to the numbers of an ineffective strain failed to result in a corresponding increase in the proportion of nodules formed by an ineffective strain. Instead, the ratio of ineffective to effective strains had to be of the order of 108/104 or wider (c. 10,000/1) before there was a substantial reduction in the number of nodules formed by the effective strains. Even when this ratio was of the order of 108/102, the effective strains still produced some of the nodules. A parallel study of the rates of nodulation of seedlings inoculated with mixtures of strains showed that these rates were characteristic of the proportions of nodules being formed by each strain. Subsequently seedlings were inoculated with mixtures of effective and ineffective strains, and after 66, 90, and 114 hr the roots were surface-sterilized and their contents isolated and identified. Independently of the mixture of strains used, most of the bacterial cells were identified as the effective strains. Because the strains of effective and ineffective bacteria used produce nodules freely when inoculated separately onto these hosts, it is postulated that the hosts distinguished between effective and ineffective strains, and that this recognition is related to compatibility in association with the host. The significance of the results in relation to studies of the root-nodule bacteria is discussed.

The root-nodule bacteria as factors in clover establishment in the red basaltic soils of the Lismore district, NSW. I. A survey of "Native" strains.

1954 ◽  
Vol 5 (1) ◽  
pp. 55 ◽  
Author(s):  
JM Vincent
Keyword(s):  
Root Nodule ◽  
New South ◽  
Field Observations ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Seed Inoculation ◽  
South Wales ◽  
Basaltic Soils ◽  
Native Strains ◽  
Medicago Species

Tests of 84 cultures of root-nodule bacteria isolated from four species of clover growing in the Lismore district of New South Wales (three soil types, 18 localities) showed them to be generally effective in association with white and red clovers, but almost always parasitic on subterranean and crimson clovers. Successful seed inoculation with beneficial strains of rhizobia is, therefore, essential to the introduction of subterranean and crimson clovers in these soils. Field observations have also demonstrated the need to inoculate seed of Medicago species, cowpea, and vetch.

The root-nodule bacteria as factors in clover establishment in the red basaltic soils of the Lismore district, NSW. II. Survival and success of inocula in laboratory trials.

1954 ◽  
Vol 5 (1) ◽  
pp. 61 ◽  
Author(s):  
JM Vincent ◽  
LM Waters
Keyword(s):  
Root Nodule ◽  
Nodule Formation ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Reasonable Degree ◽  
Seed Inoculation ◽  
Serological Identification ◽  
Small Rise ◽  
Basaltic Soils ◽  
Native Strains

Plant growth, nature of nodulation, and serological identification of cultures isolated from nodules have been used to determine the success achieved with inocula of clover rhizobia. The Lismore krasnozems offer difficulties in the way of successful seed inoculation. Milk and phosphate supplements with the inoculum do not obviate the difficulty, but heavier rates of inoculation give a reasonable degree of nodulation even with untreated soils. The unfavourable nature of these soils is reflected in their relatively low rhizobial population and the failure of added cells to persist or multiply at a rate comparable with other soils and conditions. Raising pH to c. 7 by the addition of Ca(OH)2 or CaCO3 markedly improves the soil as a medium for survival and multiplication of clover rhizobia. Even a small rise in pH gives appreciable improvement. Strains of root-nodule bacteria differ markedly in their ability to compete with each other for growth and nodule formation on a host. The relative performance of strains can be affected by such factors as the nature of the soil and the presence and nature of the host. Competition for nodulation need not be related in any simple way to competition for growth. Competition by :"native" strains can be an important factor contributing to success or failure with added inoculum.

STUDIES ON THE LEGUME ROOT NODULE BACTERIA: II. THE PRODUCTION AND BEHAVIOR OF COLONIAL MUTANTS PRODUCED BY X-RAY IRRADIATION

1952 ◽  
Vol 30 (2) ◽  
pp. 125-130 ◽  
Author(s):  
D. C. Jordan
Keyword(s):  
Root Nodule ◽  
Effective Strain ◽  
Sterile Plant ◽  
Nodule Bacteria ◽  
Artificial Medium ◽  
Serial Transfer ◽  
Root Nodule Bacteria ◽  
X Ray ◽  
Colonial Morphology ◽  
And Behavior

Four distinct types of colonial mutation were obtained by X-ray irradiation of a parasitic strain of alfalfa Rhizobium. Two types were procured from an effective strain. Colonial morphology remained stable throughout serial transfer on artificial medium, but changed considerably after one plant passage. Three variants derived from the parasitic parent were found to be efficient in nitrogen fixation when tested by sterile plant growth procedures and the Virtanen technique. This efficiency increased during the course of two plant passages. Colonial variation and effectivity changes occurred independently of one another.

Functional Specificity of the nifA Gene Product within the Group of Root Nodule Bacteria

Microbiology ◽  
2021 ◽  
Vol 90 (4) ◽  
pp. 481-488
Author(s):  
A. A. Vladimirova ◽  
R. S. Gumenko ◽  
E. S. Akimova ◽  
Al. Kh. Baymiev ◽  
An. Kh. Baymiev
Keyword(s):  
Gene Product ◽  
Root Nodule ◽  
Nodule Bacteria ◽  
Functional Specificity ◽  
Root Nodule Bacteria ◽  
Nifa Gene

scholarly journals Quantitative evaluation of acidity tolerance of root nodule bacteria

1999 ◽  
Vol 30 (3) ◽  
pp. 203-208 ◽  
Author(s):  
Luiz Antonio de Oliveira ◽  
Hélio Paracaima de Magalhães
Keyword(s):  
Root Nodule ◽  
Maximum Growth ◽  
Nodule Bacteria ◽  
Root Nodule Bacteria ◽  
Soil Persistence ◽  
Statistical Precision ◽  
Visible Growth ◽  
Selection For ◽  
Growth Scores ◽  
Selection Of

Quantification of acidity tolerance in the laboratory may be the first step in rhizobial strain selection for the Amazon region. The present method evaluated rhizobia in Petri dishes with YMA medium at pH 6.5 (control) and 4.5, using scores of 1.0 (sensitive, "no visible" growth) to 4.0 (tolerant, maximum growth). Growth evaluations were done at 6, 9, 12, 15 and 18 day periods. This method permits preliminary selection of root nodule bacteria from Amazonian soils with statistical precision. Among the 31 rhizobia strains initially tested, the INPA strains 048, 078, and 671 presented scores of 4.0 at both pHs after 9 days of growth. Strain analyses using a less rigorous criterion (growth scores higher than 3.0) included in this highly tolerant group the INPA strains 511, 565, 576, 632, 649, and 658, which grew on the most diluted zone (zone 4) after 9 days. Tolerant strains still must be tested for nitrogen fixation effectiveness, competitiveness for nodule sites, and soil persistence before their recommendation as inoculants.

Application of molecular techniques to studies in Rhizobium ecology: a review

2001 ◽  
Vol 41 (3) ◽  
pp. 299 ◽  
Author(s):  
J. E. Thies ◽  
E. M. Holmes ◽  
A. Vachot
Keyword(s):  
Root Nodule ◽  
Molecular Techniques ◽  
Nodule Bacteria ◽  
Bacterial Genomes ◽  
Root Nodule Bacteria ◽  
Bacterial Signaling ◽  
Field Environment ◽  
Background Population ◽  
Insight Into ◽  
Made In

The symbiosis between legumes and their specific root-nodule bacteria, rhizobia, has been employed to improve agricultural productivity for most of the 20th century. During this time, great advances have been made in our knowledge of both plant and bacterial genomes, the biochemistry of the symbiosis, plant and bacterial signaling and the measurement of nitrogen fixation. However, knowledge of the ecology of the bacterial symbiont has lagged behind, largely due to a lack of practical techniques that can be used to monitor and assess the performance of these bacteria in the field. Most techniques developed in the last few decades have relied on somehow ‘marking’ individual strains to allow us to follow their fate in the field environment. Such techniques, while providing knowledge of the success or failure of specific strains in a range of environments, have not allowed insight into the nature of the pre-existing rhizobial populations in these sites, nor the interaction between marked strains and the background population. The advent of molecular techniques has revolutionised the study of Rhizobium ecology by allowing us to follow the flux of a variety of ecotypes within a particular site and to examine how introduced rhizobia interact with a genetically diverse background. In addition, molecular techniques have increased our understanding of how individual strains and populations of root-nodule bacteria respond to changes in the environment and how genetic diversity evolves in field sites over time. This review focuses on recently developed molecular techniques that hold promise for continuing to develop our understanding of Rhizobium ecology and how these can be used to address a range of applied problems to yield new insights into rhizobial life in soil and as legume symbionts.

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