Associative N2-fixation in plants growing in saline sodic soils and its relative quantification based on15N natural abundance

Malik, K. A.; Bilal, Rakhshanda; Rasul, Ghulam; Mahmood, Khalid; Sajjad, M. I.

doi:10.1007/bf02187434

Cited by 24 publications

(8 citation statements)

References 23 publications

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“…(Song et al ., 2006). Sandy deserts are practically infertile, and their N content is very low (Malik et al ., 1991). The mean value of total N is 0.07 g kg − 1 dry soil in the region where H. persicum occurs (Li, 1986).…”

Section: Introductionmentioning

confidence: 99%

Nutritional and osmotic roles of nitrate in a euhalophyte and a xerophyte in saline conditions

et al. 2006

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Summary• The effects of salinity and nitrogen (N) on growth and the role of NO 3 -in osmotic adjustment in the leaf-succulent euhalophyte Suaeda physophora and the stemsucculent xerophyte Haloxylon persicum were evaluated.• Seedlings were exposed to 1 or 300 m M NaCl in 0.05, 1 or 10 m M NO 3 --N treatments for 24 d.• At 10 m M NO 3 -, 300 m M NaCl had no adverse effect on the concentration of NO 3 -, the content of organic N, and the estimated contribution of NO 3 -to osmotic potential in leaves of S. physophora , but markedly reduced these in stems of H. persicum . At 300 m M NaCl, more NO 3 -but less Cl -and Na + were involved in osmotic adjustment in leaves of S. physophora compared with that in stems of H. persicum . The contribution of NO 3 -to osmotic potential was much higher in S. physophora , but lower in H. persicum , than that of amino acids at 300 m M NaCl.• The nutritional and osmotic roles of NO 3 --N seem to be more important in the euhalophyte S. physophora than in the xerophyte H. persicum under saline conditions. These characteristics may determine the natural distributions of the two species in saline or arid environments.

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Section: Introductionmentioning

confidence: 99%

Nutritional and osmotic roles of nitrate in a euhalophyte and a xerophyte in saline conditions

et al. 2006

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“…The differential isotopic values of an N-fixer (alfalfa) and a reference plant (dandelion) can indicate relative amounts of N fixation using the assumption that all dandelion N is derived from the soil which has a specific δ 15 N value, whereas alfalfa will obtain N from both soil pools and atmospheric N 2 [36,44]. Generally, reference plants are assumed to have access to the same soil N pools as the N-fixing plant.…”

Section: Plant and Soil Analysesmentioning

confidence: 99%

“…Ecological tools can be used to directly quantify nutrient fluxes or to gain broader characterizations of the biological system. The difference in 15 N natural abundance between a non-fixing reference plant and an N-fixing legume can indicate relative differences in N fixation between treatments and over time, as well as transfer of fixed N from the N-fixing plant to the reference plant [35,36]. Since it is challenging to measure N fixation directly, it is important to employ multiple lines of evidence to measure changes in N fixation [37].…”

Section: Introductionmentioning

confidence: 99%

Nitrogen Dynamics in an Established Alfalfa Field under Low Biochar Application Rates

et al. 2019

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Sustainable nitrogen (N) management in agroecosystems is crucial for supporting crop production and reducing deleterious N losses. Biochar application with N-fixing legumes offers promise for increasing soil N retention and input. Strategic, low application rates (112 kg ha−1) of pine and coconut feedstock biochars were tested in an established alfalfa (Medicago sativa) field. Soil inorganic N and plant growth, N concentrations, and δ15N were monitored over a growing season to follow mineral N availability, and plant N uptake and sourcing. Microbial and gene abundance and enzyme activity were measured to assess the potential for N cycling processes to occur. Biochar application had minimal effects on measured parameters. However, significant temporal dynamics in N cycling and correlations between alfalfa δ15N and soil N availability indicate differing plant N sourcing over time. Our findings indicate that low application rates of biochar in established alfalfa fields do not significantly affect N cycling, and that managing alfalfa to maximize N fixation, for example by intercropping, may be a better solution to increase N stocks and retention in this system. To determine when biochar can be beneficial for alfalfa N cycling, we need additional research to assess various economically-feasible biochar application rates at different alfalfa growth stages.

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“…The separated samples were washed with tap water, rinsed with sterile water and cut into 2-3 cm long sections. All tissues were surface sterilized with 70% alcohol for 1 min, 2% NaOCl for 2 min and 70% alcohol for 30 s, followed by four washes with sterile distilled water, and then drained on sterile absorbent paper 7,14,15 . The tissues were aseptically cut into small pieces and macerated in sterile water.…”

Section: Enumeration Of Diazotroph Endophytic Bacteriamentioning

confidence: 99%

“…Morphological and biochemical characteristics were determined for Gram reaction, oxidase reaction, catalase reaction, acidification of glucose under aerobic and anaerobic conditions, and growth in nitrogen free medium. In addition, motility, pectinase and cellulase were assayed 14,19,20 .…”

Section: Characterization Of Diazotrophic Bacteriamentioning

confidence: 99%

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et al. 2007

ScienceAsia

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The population size of endophytic nitrogen fixing or diazotrophic bacteria was determined for three varieties of cultivated rice and four populations of wild rice. The dynamics of the bacterial populations from both types of rice was estimated at different stages of plant growth. The number of diazotrophic bacteria in roots, stems and leaves of all varieties of cultivated rice increased with ageing of the plants to a maximum at the heading stage (60 days after transplanting). However, nitrogenase activity could not be detected in bacterial isolates from cultivated rice. The highest bacterial population (5.25 × 10 6 per gram fresh material) was found in the roots of Oryza rufipogon, and this population showed the highest nitrogenase activity. In wild rice genotypes the populations of endophytic diazotrophs were stable, with the higher population in O. rufipogon as compared to O. rufipogon (18883) and O. nivara (18852). Cultures of diazotrophic bacteria were isolated and characterized as species of the genera Azospirillum, Herbaspirillum, Beijerinckia and Pseudomonas. All isolates were Gram negative and motile, and produced both pectinase and cellulase. Optimum growth and nitrogen fixation activity for Azospirillum sp. was recorded at 30-35 °C and pH 6.0-7.0, for Beijerinckia sp. at 25-30 °C and pH 6.0-7.5, and for Herbarspirillum sp. at 30-35 °C and pH 6.0-7.5.

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Associative N2-fixation in plants growing in saline sodic soils and its relative quantification based on15N natural abundance

Cited by 24 publications

References 23 publications

Nutritional and osmotic roles of nitrate in a euhalophyte and a xerophyte in saline conditions

Nutritional and osmotic roles of nitrate in a euhalophyte and a xerophyte in saline conditions

Nitrogen Dynamics in an Established Alfalfa Field under Low Biochar Application Rates

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