SOME FACTORS INFLUENCING THE GROWTH AND SURVIVAL OF RHIZOBIA IN HUMUS AND SOIL CULTURES

1948 ◽  
Vol 26c (2) ◽  
pp. 174-187 ◽  
Author(s):  
R. A. Hedlin ◽  
J. D. Newton
Keyword(s):  
Sodium Chloride ◽  
Calcium Carbonate ◽  
Magnesium Sulphate ◽  
Pure Culture ◽  
Mineral Soil ◽  
Growth And Survival ◽  
Factors Influencing ◽  
Pure Cultures ◽  
Dipotassium Phosphate ◽  
High Level

A study was made of the growth of rhizobia outside the host plant in three high humus mixtures and a mineral soil. Rhizobia grew better in pure cultures than in an unsterile base. Incubation in Erlenmeyer flasks gave, as a rule, higher counts than in paper cartons. Addition of a mixture of sucrose, calcium carbonate, sodium chloride, dipotassium phosphate, and magnesium sulphate led to increased numbers of rhizobia in pure culture in all bases used, and produced increased numbers in the unsterilized mineral soil also. Addition of this mixture to the unsterile high humus bases increased the total numbers of bacteria, but not the number of rhizobia. When the bases were sterilized, the highest counts of rhizobia were obtained in the high humus bases. When sterilization was not carried out, the greatest numbers of rhizobia occurred in the mineral soil. In tightly stoppered flasks that did not permit aeration, the rhizobia appeared to die out completely when stored for more than a few days, whereas in loosely stoppered flasks the counts remained at a high level until the base became desiccated.

scholarly journals Some effects of nitrogen-fixing bacteria on the growth of non-leguminous plants

1909 ◽  
Vol 81 (548) ◽  
pp. 287-289 ◽  
Keyword(s):  
Sodium Chloride ◽  
Calcium Carbonate ◽  
Mixed Culture ◽  
Ferrous Sulphate ◽  
Potassium Phosphate ◽  
Distilled Water ◽  
Leguminous Plants ◽  
Bacterial Cultures ◽  
Fluid Media ◽  
Pure Cultures

During the course of an investigation on “The Cross-inoculation of the nodule-forming bacteria from Leguminous and non-Leguminous plants,”* it was noticed that in all bacterial cultures prepared from the algal zone of the root-tubercles of cycads taken from below the surface of the soil, Pseudomonas radicicola was associated with a species of Azotobacter . In Order to determine to what extent, if any, this association gave an increased power of assimilating free nitrogen, the two forms were obtained as pure cultures by successive platings on a medium composed of maltose 20 grammes, monobasic potassium phosphate 0·5 gramme, sodium chloride 0·5 gramme, calcium carbonate 0·5 gramme, ferrous sulphate 0·1 gramme, agar 15 grammes and distilled water 1000 c. c. Separate cultures of each and a mixed culture were then grown in fluid media in duplicate 500 c. c. Erelenmeyer flasks containing 250 c. c. Of the above medium, omiting the agar but adding 10 grammes of mannite. Control flasks were kept side by side with the inoculated flasks.

Associated growth of wheat and annual ryegrass. 2. Effect of varying the time of ryegrass germination in stands of wheat

1980 ◽  
Vol 31 (4) ◽  
pp. 659 ◽  
Author(s):  
K Rerkasem ◽  
WR Stern ◽  
NA Goodchild
Keyword(s):  
Pure Culture ◽  
Fertilizer Application ◽  
Total Density ◽  
Annual Ryegrass ◽  
Competitive Effects ◽  
Pure Cultures ◽  
Reproductive Rates ◽  
Rate Of Decline ◽  
High Level ◽  
Positive Intervention

In a field experiment, wheat cv. Gamenya and annual ryegrass cv. Wimmera were sown in four proportions, 80W : 20R, 60W : 40R, 40W : 60R, 20W : 80R, at a total density of 300 plants m-2 and in which a high level of nitrogen fertilizer application was maintained. Ryegrass was sown 17 days before, simultaneously with, and 17 days after wheat. At the simultaneous sowing there were also pure cultures of wheat and ryegrass; pure culture data for ryegrass corresponding to all the germination treatments were obtained in a supplementary experiment. All treatments were harvested on five occasions. Observations were made on tiller numbers, yield of dry matter, seed numbers and the yield components of wheat. There were marked effects of early and simultaneous sowing of ryegrass and of proportions; the results also showed interactions between the later sowings and proportions. In all treatments wheat tiller numbers rose to a maximum and declined to about half after about 100 days. A similar rise and fall was observed in the early and simultaneous germination of ryegrass, but not in the late one. In ryegrass, tiller numbers were much greater than in wheat, and the rate of decline was not as marked. In the late germination treatment ryegrass development and growth were seriously depressed. With respect to wheat, seed yield and ear numbers per unit area in the early and simultaneous sowings were less, while ears and grains per plant were greater in the presence of ryegrass than in pure culture. In ryegrass, seed production was highest in the early and least in the late treatments and was depressed as the proportion of wheat was increased; even in the treatment with the lowest proportion of ryegrass, seed numbers of ryegrass remained high. Relative reproductive rates showed a consistent pattern with time of sowing and with proportion, and the results suggest that control of ryegrass seed numbers cannot be achieved by manipulating planting treatments but requires positive intervention. Relative crowding coefficients (k) calculated from the data suggest that wheat was the stronger competitor. The results are discussed in terms of the competitive effects between species and the likelihood that wheat has the greater competitive ability. As in the previous study, it was noted that effects of competition were discernible at 28 days.

The effect of salinity on the growth, water status, and ion content on Common bean (Phaseolus vulgaris. L. var. El-Djadida)

2018 ◽  
Vol 7 (4) ◽  
pp. 147-156
Author(s):  
Laredj-Zazou Rahma ◽  
Toumi Benali Fawzia ◽  
Bouazza Sofiane
Keyword(s):  
Sodium Chloride ◽  
Water Status ◽  
Phaseolus Vulgaris L ◽  
Salt Stress Tolerance ◽  
Ion Content ◽  
Organic Growth ◽  
Growth Attributes ◽  
High Concentrations ◽  
High Level ◽  
Post Stress

Stress salinity has an important effect on crops physiology. The scope of our study was to evaluate the effect of salt stress tolerance as determined through growth attributes, water status and ion content in (Phaseolus vul-garis. L), the variety of El-Djadida in 6 weeks post stress application. The ex-periment was performed under glasshouse, in controlled conditions, in pots and irrigated with nutrient solution of Hoagland. Plants were irrigated with water containing sodium chloride alone (100 and 200 meq.l-1) combined with sodium chloride (NaCl) and calcium chloride (CaCl2) (100 and 150 meq.l-1). The results obtained showed that the salt application had a depressive effect on the organic growth however, this trend was dependant on the intensity of the stress. The hydric state of the plant varied with the concentration of sub-strate, thus exhibiting the ability to moderate the sensitive plant to adjust gradually to their osmotic pressure even by maintaining high concentrations of K+. The distribution of Na+, K+ and Ca++ in plant organs leaves and roots highlighted that the high level of salinity increased with levels of Na+ which inhibited the absorption of Ca++ and K+ ions.

scholarly journals THE CONCEPT OF BUILDING OF ECONOMIC ENSURING POLICY THE COMPETITIVENESS OF INNOVATIVE BUSINESSES IS FORMED AT THE MACRO AND MICRO LEVELS

2021 ◽  
Author(s):  
Iryna Zrybnieva
Keyword(s):  
Innovation Activity ◽  
Competitive Advantages ◽  
Resource Potential ◽  
Economic Entity ◽  
Marketing Orientation ◽  
Factors Influencing ◽  
Long Run ◽  
High Level ◽  
Key Aspects ◽  
Market Relations

With the development of market relations, growing uncertainty and risk, the high level of competitiveness of the enterprise largely depends on the level of its innovation activity. In this article the author described the factors influencing the formation of the competitive potential of the subjects of innovative entrepreneurship, carried out their classification. In his opinion, the competitiveness of innovative entrepreneurs depends primarily on the economic situation achieved through economic strategy (policy). The economic policy of ensuring the competitiveness of the subjects of innovative entrepreneurship is formed both at the macroeconomic and microeconomic level. At each level of management requires a special organizational and economic approach that ensures the transformation of available resources into competitive advantages through the use of certain competencies. The author concludes that the achievement of competitive advantages in the market in the future and high competitiveness of the enterprise in the long run are possible due to efficient use of resource potential, high strategic opportunities to reproduce resource potential, strategic marketing orientation of the product offer. With the growth of the dynamics of competitiveness of the studied subject of innovative entrepreneurship, it is necessary to determine its position in the internal environment, ie to identify how the current ability to compete corresponds to the opportunities present in the external environment. With declining dynamics (as an option – the lack of dynamics), including those obtained in the current assessment of competitiveness, it is necessary to first identify the reasons for the decline in the competitiveness of the subject of innovative entrepreneurship. Given that the assessment of competitiveness integrates three key aspects, the reasons, respectively, can be social, economic or technological in nature (or be characterized by a combination of them). Competitiveness as an internal mechanism of effective activity of an economic entity transforms the market into a system of factors influencing the process of competition, thereby forming competitiveness in the field of a separate competitive field.

scholarly journals Factors influencing determination of high-level aminoglycoside resistance in Enterococcus faecalis.

1991 ◽  
Vol 29 (9) ◽  
pp. 1934-1939 ◽  
Author(s):  
D F Sahm ◽  
S Boonlayangoor ◽  
P C Iwen ◽  
J L Baade ◽  
G L Woods
Keyword(s):  
Enterococcus Faecalis ◽  
Aminoglycoside Resistance ◽  
Factors Influencing ◽  
High Level

Growth and enterotoxin B synthesis by Staphylococcus aureus S6 in associative growth with Pseudomonas aeruginosa

1973 ◽  
Vol 19 (10) ◽  
pp. 1197-1201 ◽  
Author(s):  
D. L. Collins-Thompson ◽  
B. Aris ◽  
A. Hurst
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Sodium Chloride ◽  
Salt Tolerance ◽  
Second Growth ◽  
Growth System ◽  
Pure Cultures ◽  
Enterotoxin B ◽  
Membrane Type ◽  
And Staphylococcus Aureus

The interaction of Pseudomonas aeruginosa and Staphylococcus aureus S6 was studied in two systems. In the first system, the two organisms were grown together in a single flask. Growth of P. aeruginosa was unaffected, but growth of S. aureus was modified. After 24 h, 99.9% of the staphylococci population lost their salt tolerance when plated on media containing 7.5% sodium chloride, and enterotoxin B synthesis by S. aureus was diminished. In the second growth system, pure cultures of P. aeruginosa and S. aureus were grown in membrane-type spinner flasks. The growth and salt tolerance of S. aureus was again affected, but to a lesser degree. Cultures of S. aureus from these experiments recovered their salt tolerance in 6 h when transferred to fresh medium.Nutrient deficiency, lack of oxygen, or pigment production by the pseudomonads did not contribute significantly to loss of salt tolerance or inhibition of enterotoxin B synthesis, but a staphylolytic enzyme(s) isolated from P. aeruginosa was shown to be responsible for the loss of these properties.

scholarly journals Alternate Strip Clearcutting in Upland Black Spruce: II. Factors Affecting Regeneration in First-cut Strips

1987 ◽  
Vol 63 (6) ◽  
pp. 439-445 ◽  
Author(s):  
John K. Jeglum
Keyword(s):  
Natural Regeneration ◽  
Black Spruce ◽  
Mineral Soil ◽  
Strip Width ◽  
Seedling Density ◽  
Factors Affecting ◽  
Topographic Position ◽  
Factors Influencing ◽  
Main Factors ◽  
Upper Slope

In a two-cut, alternate strip clearcutting system in upland black spruce, the main factors influencing black spruce regeneration in the first-cut strips were strip width, natural seeding period, amount of receptive seedbed and topographic position. In the three study areas, 80-m strips yielded over 60% stocking and over 7 500 seedlings per hectare with a 4-year natural seeding period. Narrower strips 40 m and 20 m wide showed increasing levels of reproduction. Four years of natural seeding gave better natural regeneration than two years. Seedling density and frequency in quadrats were correlated with the amount of receptive seedbed. Regeneration was more abundant on drainageways and lower slopes, and less abundant on upper slope and crest sites. For successful regeneration under similar climatic and physiographic conditions, strip widths should be no more than 80 m, and leave times no less than 3 years. It is essential to scarify the upland mineral soil sites, but scarification of lowland sites is not recommended, especially where there is abundant Sphagnum.

Sign in / Sign up

Export Citation Format

Share Document