scholarly journals Competition between related strains of nodule bacteria and its influence on infection of the legume host

1941 ◽  
Vol 130 (858) ◽  
pp. 32-59 ◽  
Keyword(s):  
Growth Rate ◽  
Nitrogen Fixation ◽  
Root System ◽  
Short Duration ◽  
Pure Culture ◽  
The Other ◽  
Initial Growth ◽  
Nodule Bacteria ◽  
Long Period ◽  
Different Strains

The work deals with the behaviour of mixed strains of nodule bacteria towards each other and towards their legume host. It introduces the concept of dominance in competition between strains. This dominance is independent of degree of effectiveness as regards nitrogen fixation. Where tow strains of nodule bacteria are both present in the surroundings of their host's root system, active competition between them may cause the strain having the higher initial growth rate almost completely to check multiplication of the other strain outside the plant. This dominant strain will then be responsible for nearly all the nodules. In peas and soy beans, where growth of the root sysytem is rapid and of comparatively short duration, the nodule-producing capacity of the plant may be partially or wholly satisfied by the nodules produced within the first few weeks, so that further infection, whether by the same or by a different strain, is checked or inhibited. In clover, whose root system continues to grow over a long period, the first-formed nodules do not stop further nodules from being formed either by the same or by a different strain. There are large differences in the rates of appearance and final numbers of nodules produced by different strains supplied in pure culture, particularly with clover. The relative numbers of nodules produced by the two strains simultaneously applied to the roots is conditioned by the specific infectivity peculiar to each strain, unless some other factor, such as competition outside the plant, masks this effect.

The influence of the number of nodule bacteria applied to the seed upon nodule formation in legumes

1929 ◽  
Vol 19 (2) ◽  
pp. 373-381 ◽  
Author(s):  
H. G. Thornton
Keyword(s):  
Pure Culture ◽  
Field Trial ◽  
Root Hairs ◽  
The Other ◽  
Pot Experiment ◽  
Nodule Formation ◽  
Nodule Bacteria ◽  
Soil Population ◽  
Other Hand ◽  
The Difference

In a field trial with lucerne grown from seed treated with varying doses of culture it was found that the numbers of nodules were increased as the dose was raised from 2,500 to 20,000 organisms per seed (56 to 7 Ib. of seed per culture). Storing the seed for periods up to 28 days between inoculation and sowing, caused some loss in the nodule numbers. This loss was greatest between 1 and 7 days' storage.The difference in dose of culture and in period of storage did not significantly affect the crop subsequently obtained from the inoculated plots, whose yield was, however, much above the uninoculated.In a pot experiment made with runner beans, it was found that increase in the dose of culture above 1,280,000,000 organisms per pot containing six seeds was still capable of increasing nodule numbers but not to an extent proportional to the increase in dose.The experiment does not exclude the possibility that the restriction in effect of very heavy doses may be due to the soil population becoming saturated with the bacteria. On the other hand, observations on lucerne plants grown aseptically on agar and inoculated with a pure culture, showed that even when excessive numbers of the bacteria immediately surrounded the root hairs, only 4 per cent, of these were infected.

scholarly journals Legume Symbiotic Nitrogen Fixation byβ-Proteobacteria Is Widespread inNature

2003 ◽  
Vol 185 (24) ◽  
pp. 7266-7272 ◽  
Author(s):  
Wen-Ming Chen ◽  
Lionel Moulin ◽  
Cyril Bontemps ◽  
Peter Vandamme ◽  
Gilles Béna ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Nitrogen Fixation ◽  
Phylogenetic Tree ◽  
Phylogenetic Diversity ◽  
Symbiotic Nitrogen Fixation ◽  
The Other ◽  
Gene Sequences ◽  
Free Living ◽  
Initial Discovery ◽  
Different Strains

ABSTRACT Following the initial discovery of two legume-nodulating Burkholderia strains (L. Moulin, A. Munive, B. Dreyfus, and C. Boivin-Masson, Nature 411:948-950, 2001), we identified as nitrogen-fixing legume symbionts at least 50 different strains of Burkholderia caribensis and Ralstonia taiwanensis, all belonging to the β-subclass of proteobacteria, thus extending the phylogenetic diversity of the rhizobia. R. taiwanensis was found to represent 93% of the Mimosa isolates in Taiwan, indicating thatβ -proteobacteria can be the specific symbionts of a legume. The nod genes of rhizobial β-proteobacteria (β-rhizobia) are very similar to those of rhizobia from theα -subclass (α-rhizobia), strongly supporting the hypothesis of the unique origin of common nod genes. Theβ -rhizobial nod genes are located on a 0.5-Mb plasmid, together with the nifH gene, in R. taiwanensis and Burkholderia phymatum. Phylogenetic analysis of available nodA gene sequences clustered β-rhizobial sequences in two nodA lineages intertwined with α-rhizobial sequences. On the other hand, theβ -rhizobia were grouped with free-living nitrogen-fixingβ -proteobacteria on the basis of the nifH phylogenetic tree. These findings suggest that β-rhizobia evolved from diazotrophs through multiple lateral nod gene transfers.

scholarly journals The reaction of self-fertile alfalfa lines to inoculation with nodule bacteria

2020 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Sinorhizobium Meliloti ◽  
Root Nodules ◽  
Growing Season ◽  
Dry Mass ◽  
Nodule Bacteria ◽  
Forage Crop ◽  
Nitrogen Fixation Activity ◽  
Fixation Activity ◽  
Different Strains

Under the conditions of a model pot experiments, the reaction of the self-fertile lines of alfalfa Kishvardy 46, Kishvardy 27, Vertus and Ziguen to inoculation with nodule bacteria Sinorhizobium meliloti AC48 and AC88 was studied. As a result of studies, it was found that the intensity of assimilation of N2 by symbiotic systems created with the participation of various genotypes of alfalfa and active strains of S. meliloti is one of the main factors that affects the vegetative mass yield of this important forage crop. Self-fertile lines of Medicago sativa L. plants, inoculated with different strains of rhizobia were characterized by higher rates of the mass formed on the root nodules, compared to the control plants of the alfalfa variety Yaroslavna. The traditional dynamics of nitrogen-fixation activity of root nodules was maintained in all the symbiotic systems studied by us, with low values in the stems formation stage and intensive growth in the budding and flowering stages. The highest level of nitrogen fixation and vegetative growth of plants (values of plants green and dry mass, roots and root nodules mass) was established by inoculation of alfalfa line Kishvardy 46 with strain S. meliloti AC48. During the growing season the indices of the mass of nodules formed on the roots of these plants were higher by 1.8–2.3 times, the green mass by 1.2–1.6 times and the height of the plants 1.2–1.4 times as compared to the control. In the flowering stages the nitrogen-fixation activity of the symbiotic complex of plants of the Kishvardy line 27 and nodule bacteria S. meliloti AC48 exceeded the values in the symbiotic systems formed with the participation of the same strain and plants of the Ziguen and Vertus lines by 13.0 and 39.4 %. The lowest values of nitrogen fixation activity were observed by inoculation of plants of the Vertus and Ziguen lines with active strains S. meliloti AC48 and AC88 compared to the symbioses formed by the plants of the Kishvardy lines 27 and 46, as well as of the control-variety Yaroslavna with the noted strains. A stimulating effect of inoculation of alfalfa seeds of different genotypes on the growth and development of plants was noted, as evidenced by the positive dynamics of the increase in above-ground mass, the accumulation of dry matter and higher than the control values (indicators) of plant height during the growing season.

scholarly journals Pseudomonas aeruginosacross-colonization and persistence in patients with cystic fibrosis. Use of a DNA probe

1989 ◽  
Vol 102 (2) ◽  
pp. 205-214 ◽  
Author(s):  
Christiane Wolz ◽  
Gerd Kiosz ◽  
John W. Ogle ◽  
Michael L. Vasil ◽  
Urs Schaad ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Antibiotic Therapy ◽  
Summer Camp ◽  
Dna Probe ◽  
The Other ◽  
Sibling Pairs ◽  
Long Period ◽  
Strain Change ◽  
Before And After ◽  
Different Strains

SUMMARYTo investigate cross-colonization with and persistence ofPseudomonas aeruginosain cystic fibrosis (CF). 181 isolates from 76 CF patients were typed using aP. aeruginosa-specific DNA probe. Whereas sibling pairs predominantly harboured genotypically identicalP. aeruginosastrains, all of the other patients harboured different strains. Seventy-nine per cent (22/31) of the infected CF patients harboured the same strains at the beginning and the end of a summer camp. A change of strains was seen in 10% (3/31) of the patients at the end of the camp. Forty-six per cent (6/13) of the patients who were apparently initially uninfected, acquiredP. aeruginosaby the end of the period. Genotyping proved that strain change or acquisition was due to cross-colonization in four of nine cases. Very littleP. aeruginosawas isolated from the inanimate environment. Persistence ofP. aeruginosaafter a temporary loss due to antibiotic therapy was seen in 12/16 paired patient strains before and after antibiotic therapy. Thus, suppression followed a flare-up seemed to occur in these patients rather than eradication and a new infection. When 35 patients were followed over a period of 6 months, 7 (20%) changed the strain in their sputum. Only one of 43 patients harboured two differentP. aeruginosastrains simultaneously over a long period.

scholarly journals The growth of nodule bacteria in the expressed juices from legume roots bearing effective and ineffective nodules

1940 ◽  
Vol 129 (857) ◽  
pp. 475-491 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Host Plants ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Nodule Growth ◽  
Different Strains

Strains of pea and soy-bean nodule bacteria, differing in their effectiveness in benefiting the host legume, were grown in media containing the unheated root juices from uninoculated host plants and from host plants bearing effective and 'ineffective' nodules, and their growth was measured. The growth of the different bacterial strains on root juice from uninoculated plants was not correlated with their effectiveness. The juice from roots with effective nodules produced significantly better growth of the bacteria than juice from roots with ineffective nodules in twenty-seven comparisons out of forty-four, the differences in the remaining comparisons being insignificant. The juice from roots with effective nodules produced significantly better growth than the juice from uninoculated roots in ten comparisons out of twenty-five, and significantly poorer growth in three comparisons. The juice from roots with ineffective nodules produced significantly poorer growth than the juice from uninoculated plants in eleven comparisons out of twenty-five, and better growth in only one comparison. The production, as a result of infection, of soluble substances affecting growth of the bacteria, affords an explanation of those differences in nodule growth that determine the effectiveness or ineffectiveness of the different strains of bacteria as regards nitrogen fixation within the host.

Phytotoxicity, Leachability, and Site of Uptake of 2-chloro-2′,6′-diethyl-N-(methoxymethyl) acetanilide

Weed Science ◽  
1969 ◽  
Vol 17 (4) ◽  
pp. 441-444 ◽  
Author(s):  
Y. Eshel
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Gossypium Hirsutum ◽  
Root System ◽  
Soil Depth ◽  
The Other ◽  
Slight Reduction ◽  
Culture Solution ◽  
Other Hand ◽  
Different Soils

The toxicity, leachability, and site of uptake of the herbicide 2-chloro-2',6'-diethyl-N-(methoxymethyl) acetanilide (hereinafter referred to as CP 50144) were studied in different soils. Two inches of water leached most of the compound to a soil depth of 2 to 3 inches, when applied at rates of 1 and 2 kg/ha. The inherent toxicity of CP 50144 to cotton (Gossypium hirsutumL., var. Acala 4-42) was studied in culture solution. The herbicide was most toxic to cotton when the entire root system of the crop was exposed to soil treated with CP 50144; reduction of weight of seedlings was accompanied by severe inhibition of root growth. On the other hand, only a slight reduction in growth rate was noticed when only the shoot zone of cotton was exposed to the herbicide.

scholarly journals EFFECT OF GOAT’S-RUE RHIZOBIA ON THE FORMATION AND FUNCTIONING OF THE SOYBEAN – BRADYRHIZOBIUM JAPONICUM 634B SYMBIOSIS

2019 ◽  
Vol 29 ◽  
pp. 29-36
Author(s):  
N. M. Melnykova ◽  
S. Ya. Kots
Keyword(s):  
Nitrogen Fixation ◽  
Root System ◽  
Bradyrhizobium Japonicum ◽  
Aerial Part ◽  
Nodule Formation ◽  
Nodule Bacteria ◽  
Rhizobial Symbiosis ◽  
Soybean Nodule ◽  
Soybean Plants ◽  
Observation Period

Objective. Study the peculiarities of nodule formation upon the formation of the symbiotic sys-tem soybean-Bradyrhizobium japonicum 634b, as well as the symbiotic nitrogen-fixation ability and plant growth and development under the influence of goat’s-rue rhizobia. Methods. Microbiologi-cal, physiological, statistical, gas chromatography. Results. In green house experiments, using sand as a substrate for growing plants, the mixed microbial cultures combining soybean nodule bacteria B. japonicum 634b and goat’s-rue nodule bacteria R. galegae 0702 or R. galegae 0703 in the ratio of 1 : 1 differed from the monoculture bradyrhizobium by their influence on the nodulation, nitro-gen-fixation ability of soybean-rhizobial symbiosis and development of soybean plants (variety Almaz). Increased nodulation activity in the primordial leaf and budding phases, as well as a signif-icant decrease in the level of symbiosis nitrogen fixation during budding, were observed when used in binary bacterial compositions of strain R. galegae 0703. These rhizobia of goat’s-rue suppressed the development of the root system of soybeans, but had no significant effect on the formation of the aerial part of the plants throughout the observation period. R. galegae 0702 strain slightly slowed the formation of nodules by bacteria in the primordial leaf phase, which caused a decrease in the number of soybean plants that formed symbiosis with B. japonicum 634b. Goat’s-rue nodule bacte-ria R. galegae 0702 improved the formation of the root system, and stimulated the growth and de-velopment of the aerial part of the macro symbiont in the phase of two trigeminal leaves. Conclu-sion. Combined inoculation of the rhizobia of goat’s-rue with nodule bacteria B. japonicum 634b showed a multidirectional effect on the formation of symbiosis by soybean plants of variety Almaz and functioning of soybean rhizobial symbiosis. The nature of the influence of R. galegae depended on their strain affiliation.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Effect of intercrops on growth and yield of turmeric (Curcuma longa L.)

2017 ◽  
Vol 26 (1) ◽  
pp. 51
Author(s):  
R Chitra, P Hemalatha
Keyword(s):  
Short Duration ◽  
Agricultural Research ◽  
Curcuma Longa ◽  
Growth And Yield ◽  
Research Station ◽  
Initial Growth ◽  
Agricultural Research Station

The initial growth of turmeric is rather slow and takes about 4-5 months to cover the inter space. Therefore, the available space between the rows of turmeric could be effectively utilized by growing short duration crops like, vegetables, cereals etc. Hence, it is worthwhile to explore the possibilities of growing compatible crops with turmeric. With this background the experiment on effect of intercrops on growth and yield of turmeric was conducted at Agricultural Research Station, Bhavanisagar. Among the different intercrops, turmeric with cowpea recorded the maximum fresh rhizome yield per hectare (30.78 t ha-1) while turmeric + bhendi registered the maximum B:C ratio (2.68:1). Monocropping of turmeric recorded the lowest B:C ratio (1.67:1) among all the treatments.  

Biodegradation of chlorophenols by immobilized pure-culture microorganisms

1996 ◽  
Vol 34 (10) ◽  
pp. 67-72 ◽  
Author(s):  
Lu Chih-Jen ◽  
Lee Chi-Mei ◽  
Huang Chiou-Zong
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Pseudomonas Putida ◽  
Pure Culture ◽  
The Other ◽  
Batch Reactors ◽  
Agrobacterium Radiobacter ◽  
Culture Cells ◽  
Lag Period

The biodegradation of phenol and chlorophenols by immobilized pure-culture cells was conducted by a series of batch reactors. The microorganisms used in this study were Pseudomonas putida, Psuedomonas testosteroni, Pseudomonas aeruginosa, and Agrobacterium radiobacter. All four species showed the ortho-cleavage pathway to metabolize chlorophenols. Among the four species, P. testosteroni, P. putida, and P. aeruginosa could effectively remove phenol at 200 mg/l. P. testosteroni could effectively remove 2-chlorophenol at 10mg/l. However, the other three species, P. putida, P. aeruginosa, and A. radiobacter, could not effectively remove 2-chlorophenol. Although 3-chlorophenol is a recalcitrant compound, P. testosteroni also could rapidly metabolize 3-chlorophenol at 10 mg/l. The removal of 4-chlorophenol at 10 mg/l by P. testosteroni reached 98% within one day. P. aeruginosa and A. radiobacter also could metabolize 4-chlorophenol after 2 and 7 days of lag period, respectively.

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