Rapid method for determination of nitrate in plant and soil extracts

Lowe, R. H.; Hamilton, James L.

doi:10.1021/jf60150a002

Cited by 137 publications

(64 citation statements)

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“…Shoot and root NO 3 À concentrations were evaluated from aqueous extraction as described by Lowe and Hamilton. 24 Briefly, 0.1 g of dry leaf was extracted with 10 mL of deionized water at 80°C for 10 min. NO 3 À was determined by ion exchange chromatography (Dionex Corp., Sunnyvale, CA).…”

Section: ' Materials and Methodsmentioning

confidence: 99%

Improvement of Nutritional Quality of Greenhouse-Grown Lettuce by Arbuscular Mycorrhizal Fungi Is Conditioned by the Source of Phosphorus Nutrition

Baslam¹,

Pascual²,

Sánchez‐Díaz³

et al. 2011

J. Agric. Food Chem.

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The improvement of the nutritional quality of lettuce by its association with arbuscular mycorrhizal fungi (AMF) has been recently reported in a previous study. The aim of this research was to evaluate if the fertilization with three P sources differing in water solubility affects the effectiveness of AMF for improving lettuce growth and nutritional quality. The application of either watersoluble P sources (Hewitt's solution and single superphosphate) or the water-insoluble (WI) fraction of a "rhizosphere-controlled fertilizer" did not exert negative effects on the establishment of the mycorrhizal symbiosis. AMF improved lettuce growth and nutritional quality. Nevertheless, the effect was dependent on the source of P and cultivar. Batavia Rubia Munguía (green cultivar) benefited more than Maravilla de Verano (red cultivar) in terms of mineral nutrients, total soluble sugars, and ascorbate contents. The association of lettuce with AMF resulted in greater quantities of anthocyanins in plants fertilized with WI, carotenoids when plants received either Hewitt's solution or WI, and phenolics regardless of the P fertilizer applied.

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Section: ' Materials and Methodsmentioning

confidence: 99%

Improvement of Nutritional Quality of Greenhouse-Grown Lettuce by Arbuscular Mycorrhizal Fungi Is Conditioned by the Source of Phosphorus Nutrition

Baslam¹,

Pascual²,

Sánchez‐Díaz³

et al. 2011

J. Agric. Food Chem.

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“…Carbohydrate was assayed with anthrone (22) using a sucrose standard; it was verified that an invert mixture gave the same color as the equivalent amount of sucrose. Nitrate was determined with the soybean bacteroid technique of Lowe and Hamilton (13). When using the above assays with phloem exudate, small amounts of EDTA and PEG were sometimes present; it was found that this did not interfere with any of the assays.…”

Section: Methodsmentioning

confidence: 99%

Amino Acids Translocated from Turgid and Water-stressed Barley Leaves

Tully

Hanson²

1979

Plant Physiol.

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The phloem exudation technique of King and Zeevaart (Plant Physiol 1974 53: 96-103) was modified for use with barley plants, to investigate the effect of water stress upon amino acid translocation at seedling and grainfilled stages.Seedling leaves and flag leaves from unstressed and moderately waterstressed plants exuded "CO2 assimilates, sugars, and amino acids when their sheaths were cut and immersed in a 5 millimolar solution of Na2EDTA (pH 7.0). By including PEG 6000 (-10 bars) Major amino acids in exudate from unstressed seedling and flag leaves were glutamine, glutamate, serine, alanine, and aspartate; proline was virtually absent. Exudate from water-stressed leaves contained relatively more serine, and also some proline and y-aminobutyric acid.While sucrose is well established as the principal sugar transported in the phloem of cereals (e.g. 3), there are few previous reports on the nitrogenous phloem constituents in these crops ( 18). The N-compounds moving in the phloem of cereals may originate from either or both of the following sources: (a) recent N assimilation (18, 23 and refs. cited therein), and (b) hydrolysis of leaf proteins, which occurs during senescence (1) and episodes of water stress (23). Although it is clear that the relative importance of sources (a) and (b) changes both with developmental stage and with environmental conditions, little is known about the chemical forms of N which these sources make available for phloem transport. Such descriptive information on the N-compounds in the phloem of cereals is pertinent to understanding the striking capacity of these plants to remobilize N from leaves and stems, sometimes directing over 70%'o of total plant N to the grains; it is also needed for quantitative treatments of partitioning of assimi- (23), and were used at 19 days (three-leaf stage), or at 21 to 24 days (four-leaf stage). Such plants were water-stressed by flooding the roots with polyethylene glycol (PEG 6000) solution 1 day prior to use, as described previously (23). Plants for experiments with flag leaves were grown in the greenhouse in a soil mixture (7)

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“…and nitrate. For a complete analysis of tissue nitrogen, a Kjeldahl digestion (8) is used for insoluble N, the SRN procedure for the SRN and one of two colorimetric assays for nitrate (2,5).…”

Section: Resultsmentioning

confidence: 99%

Minimizing Nitrate Reduction during Kjeldahl Digestion of Plant Tissue Extracts and Stem Exudates

Pace¹,

MacKown²,

Volk³

1982

Plant Physiol.

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MATERIALS AND METHODS ['4NJnitrate. Immediately after harvesting, the tissue was frozen with Dry Ice. The frozen tissue was then lyophilized and finally ground to a fine powder. Ten g ground shoot tissue were extracted with three successive 500-ml aliquots of MCW4 (13:4:3 by volume, see reference 12). The extract was separated into two phases, chloroform and methanol:water. The chloroform phase was discarded. The methanol:water phase was surface-aerated overnight at room temperature to remove methanol. The remaining liquid, which contained [14N]nitrate, organic nitrogen, and some dissolved methanol, was used for the subsequent procedural tests. Nitrate in the liquid was determined using the method of Cataldo et al. (2).Stem exudate was collected from 5-day-old, dark-grown com seedlings (DeKalb XL-45) which had been cultured on a minus-N nutrient solution (6) for 3 previous days. The resulting exudate was nitrate-free (verified by the method of Cataldo et al. (2), data not shown) and was used in the tests as collected.A salt solution of (NH4)2SO4 and KNO3 was also used in the various tests for comparison.Reduction of Nitrate during Digestion. The extent to which nitrate was reduced during Kjeldahl digestion was tested by adding selected quantities of KlNO3 to each of the three kinds of samples previously described. The final '5N enrichment of nitrate was approximately 50 atom %. Appearance of '6N in reduced N was used to indicate that reduction of nitrate had occurred during digestion of the sample. The atom per cent excess 15N observed in the reduced N fraction was used to calculate the total quantity of nitrate (14N + 15N) that had been reduced.The Kjeldahl procedure of McKenzie and Wallace (8) was followed, using 2.5 ml 36 N H2SO4, 1.5 g K2SO4, and 50 mg HgO as HgSO4. Samples were digested in a heating block for 1 h at 200°C to remove H20. The temperature was then increased and the samples were digested for an hour after the block reached 380°C (total time approximately 3 h). Ammonium was determined directly on the digestate (3).Nitrate Volatilization. The proposed procedure depends on the removal of nitrate by volatilization as nitric acid from concentrated H2SO4. The completeness ofnitrate volatilization was tested by heating selected quantities of umol)

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Rapid method for determination of nitrate in plant and soil extracts

Cited by 137 publications

References 2 publications

Improvement of Nutritional Quality of Greenhouse-Grown Lettuce by Arbuscular Mycorrhizal Fungi Is Conditioned by the Source of Phosphorus Nutrition

Improvement of Nutritional Quality of Greenhouse-Grown Lettuce by Arbuscular Mycorrhizal Fungi Is Conditioned by the Source of Phosphorus Nutrition

Amino Acids Translocated from Turgid and Water-stressed Barley Leaves

Minimizing Nitrate Reduction during Kjeldahl Digestion of Plant Tissue Extracts and Stem Exudates

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