Effects of Salt Stress on Growth, Nodulation and Nitrogen Fixation in Cowpea and Mung Beans

Balasubramanian, V.; Sinha, S. K.

doi:10.1111/j.1399-3054.1976.tb03935.x

Cited by 66 publications

(18 citation statements)

References 9 publications

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“…Mainly, the early events, more related to the physiology of the root hair such as its growth, diameter, structure, and curling, appear to be hampered by drought (Worall and or salt stress (Balasubramanian and Sinha, 1976;Tu, 1981;Singleton and Bohlool, 1984;Zahran and Sprent, 1986;Ikeda, 1994). On the contrary, the early events related to the rhizobial genome, such as the nodD and nodABC expression in B. japonicum (Wang and Stacey, 1990), seem to be little affected by changes in osmolarity.…”

Section: Osmotic Stressesmentioning

confidence: 87%

Factors Influencing Nodule Occupancy by Inoculant Rhizobia

Vlassak

Vanderleyden

1997

Critical Reviews in Plant Sciences

115

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Section: Osmotic Stressesmentioning

confidence: 87%

Factors Influencing Nodule Occupancy by Inoculant Rhizobia

Vlassak

Vanderleyden

1997

Critical Reviews in Plant Sciences

115

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“…Nitrogen fixing rhizobia cannot express their full potential in fixing nitrogen if the environment and the plant is in poor state [97] [98]. The process of nitrogen fixation depends much on the functional state of the legume plant [99] and the optimum environmental conditions supporting the macro and microsymbionts.…”

Section: The Factors Affecting Rhizobia Population Legume and Nitrogmentioning

confidence: 99%

Isolation and Characterization of Nitrogen Fixing Rhizobia from Cultivated and Uncultivated Soils of Northern Tanzania

Simon¹,

Mtei²,

Gessesse³

et al. 2014

AJPS

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Soil bacteria 1 called rhizobia are gram-negative capable to colonize the soil immediately surrounding roots under the influence of the plant "rhizosphere" and reduce atmospheric nitrogen into the form available to plants through nitrogen fixation process. Nitrogen is the most limiting and supplied nutrient to most plants, and the determinant of plant growth. Legumes differ with most plants because they have access to nitrogen from both mineral and symbiotic sources. Small-scale farmers who are the major legume producers in Africa rarely apply fertilizers during legume production. Hence, the crop is largely dependent on fixed nitrogen from native nitrogen fixers. Isolation of rhizobia for legume production has been given a little attention in Africa due to inadequate research or negligence of researchers and unawareness of its potential in legume production as well as lack of an intention from skilled personnel to popularize the technology. Evaluation of effectiveness of isolated rhizobia is essential for inoculants preparation, host specificity recommendation and symbiotic effectiveness. The isolation, determination of their population in the soil and assessing factors affecting their population and testing the effectiveness of native nitrogen fixers with respect to right trap host crop are given a special attention in this review.

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“…Legumes grown in saline environments exhibit reduced yield potential and reduced numbers and weight of root nodules (1,14,15, 22, 24). There were, however, serious limitations in the above studies for evaluating the effects of salinity on the early stages of nodule formation.…”

Section: Introductionmentioning

confidence: 99%

Effect of Salinity on Nodule Formation by Soybean

Singleton¹,

Bohlool²

1984

Plant Physiol.

225

105

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A split-root growth system was employed to evaluate the effect of NaCl on nodule formation by soybean (Glycine max L. Meff. cv Davis). By applying the salinity stress and rhizobial inoculum to only one-half the root system, the effects of salinity on shoot growth were eliminted in the nodulation process. Rhizobium colonization of inoculated root surfaces was not affected by the salt treatments (0.0, 26.6, 53.2, and 79.9 millimolar NaCI). While shoot dry weight remained unaffected by the treatments, total shoot N declined from 1.26 grams N per pot at 0.0 millimolar NaCI to 0.44 grams N per pot at 79.9 millimolar NaCl. The concentration of N in the shoot decreased from 3.75% N (0.0 millimolar NaCI) to 1.26% N at 79.9 millimolar NaC. The decrease in shoot N was attributed to a sharp reduction in nodule number and dry weight. Nodule number and weight were reduced by approximately 50% at 26.6 millimolar NaCl, and by more than 90% at 53.2 and 79.9 millimolar NaO. Nodule development, as evidenced by the average weight of a nodule, was not as greatly affected by salt as was nodule number. Total nitrogenase activity (C2H2 reduction) decreased proportionally in relation to nodule number and dry weight. Specific nitrogenase activity, however, was less affected by salinity and was not depressed signficantly ntil 79.9 milimolar NaCI. In a second experiment, isolates of Rhizobium japonicum from nodules formed at 79.9 millimolar NaC did not increase nodulation of roots under salt stress compared to nodule isolates from normal media (0.0 millimolar NaCl). Salt was applied (53.2 millimolar NaC) to half root systems at 0, 4, 12, and 96 hours from inoculation in a third experiment. By delaying the application of salt for 12 hours, an increase in nodule number, nodule weight, and shoot N was observed.Nodule formation in the 12-and 96-hour treatments was, however, lower than the control. The early steps in nodule initiation are, therefore, extremely sensitive to even low concentrations of NaCl. The sensitivity is not related to rhizobial survival and is probably due to the salt sensitivity of root infection sites.Rhizobium growth and survival are generally more tolerant in vitro to high osmotic pressures than are their respective host legumes (8,15, 17). Tu (22), however, observed reduced colonization of soybean root surfaces by Rhizobium japonicum when plants were grown in salinized culture medium.Legumes grown in saline environments exhibit reduced yield potential and reduced numbers and weight of root nodules (1,14,15, 22, 24). There were, however, serious limitations in the above studies for evaluating the effects of salinity on the early stages of nodule formation. With the exception of the work of Lakshmi et al. (14), inoculation of seedlings with Rhizobium preceded the salinization of the rooting medium. It is likely that in these studies some critical steps of rhizobial attachment and infection thread formation could have occurred before the introduction of the salt stress. In the study of Lakshmi et aL, (14) plant...

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Effects of Salt Stress on Growth, Nodulation and Nitrogen Fixation in Cowpea and Mung Beans

Cited by 66 publications

References 9 publications

Factors Influencing Nodule Occupancy by Inoculant Rhizobia

Factors Influencing Nodule Occupancy by Inoculant Rhizobia

Isolation and Characterization of Nitrogen Fixing Rhizobia from Cultivated and Uncultivated Soils of Northern Tanzania

Effect of Salinity on Nodule Formation by Soybean

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