An Automated Method for the Determination of Orthophosphate in the Presence of Labile Polyphosphates

Asher, Leon

doi:10.2136/sssaj1980.03615995004400010037x

Cited by 23 publications

(8 citation statements)

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“…Pi was extracted from YMLs using ice-cold 0 2M perchloric acid (Irving and Bouma, 1984) and P, concentration in the extract determined by a manual modification of the method of Asher (1980). P, in YMLs was determined by the method of Haslemore and Roughan (1976), the volume ofthe initial solution in sulphuric acid/hydrogen peroxide being 2 ml.…”

Section: Methodsmentioning

confidence: 99%

The effects of phosphorus and form of nitrogen supply on leaf cell size and nutrient content in Trifolium repens and Lotus uliginosus

Hart

Collier

1994

Grass and Forage Science

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White clover (Grasslands Huia) and lotus (Grasslands Maku) were grown in pots of soil at a range of phosphorus supply, and reliant on symbiotic nitrogen fixation (SN plants) or entirely on mineral nitrogen {MN plants). Shoots increased in weight with phosphorus supply. White clover MN shoots were bigger than those of SN plants except at the lowest level of phosphorus supply; lotus MN shoots were only bigger than SN shoots at the highest level of phosphorus supply. Leaf growth rate and size increased with phosphorus supply but were not significantly affected by the nitrogen treatments.Estimates of cell size were made by determining DNA concentration, by digestion of tissue followed by counting and by taking vinyl impressions of epidermal cell surfaces. Lotus cells are bigger than those of white clover. "Digested' cell sizes were not significantly afTected by changes in phosphorus supply. Epidermal cell size increased with phosphorus supply, but the relationship was weaker in SN than in MN plants. Methods which give values for 'average' cell size are capable of detecting large-scale diiTerences. but methods able to resolve cell heterogeneity are necessary for an accurate picture of the relationship between leaf growth and cellular nutrition.Average concentrations of total and inorganic phosphorus on a DNA basis did not differ between the species, contrary to concentrations on a dry weight basis, indicating that differences in phosphorus efficiency can be partly explained on

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Section: Methodsmentioning

confidence: 99%

The effects of phosphorus and form of nitrogen supply on leaf cell size and nutrient content in Trifolium repens and Lotus uliginosus

Hart

Collier

1994

Grass and Forage Science

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“…Methanol was removed from aliquots of the aqueous-methanol phase by evaporation with air and the Pi determined manually by the method of Asher (1980). Other aliquots of this phase were evaporated to dryness, digested with perchloric acid, and the total aqueous P determined.…”

Section: Methodsmentioning

confidence: 99%

Phosphorus fractions in trifoliate leaves of white clover and lotus at various levels of phosphorus supply

Hart¹,

Jessop²

1983

New Zealand Journal of Agricultural Research

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The concentrations of total P, inorganic (Pi), lipid, and ester P were measured in the youngest mature trifoliate leaves of white clover and lotus plants grown at various levels of P supply, In white clover, the Pi concentration rose as the P supply increased, even though there was no dry matter response by the shoots at the highest levels of P, In contrast, the shoot dry weight of lotus, which was generally higher than that of white clover, continued to increase over the whole range of P supply, and the Pi concentration remained unchanged, The concentration of lipid and ester P in both species increased only slightly with P supply, The concentration of total P declined markedly with trifoliate leaf age in lotus, The concentration of Pi, lipid P, and ester P also declined but less so, The P content and dry weight of basal leaflets of lotus leaves was about 25 % of that of the trifoliate leaves, White clover is typical of plants from fertile sites, Its growth responds markedly to increase in P supply, excess Pi being stored in vacuoles, Lotus can grow well at both high and low P supply, and P concentrations in the shoots are maintained at relatively low levels, This behaviour is in contrast to that of other plants adapted to low soil fertility,

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“…Soil test phosphorus concentration (STP), commonly used for agricultural nutrient management, was conducted using the Mehlich-3 extractant [26]. STP in the extract was determined by the molybdenum blue method [27]. P pools in sediment core segments were sequentially extracted into exchangeable P (EX-P), P adsorbed to amorphous iron (Fe-P), and calcium phosphate minerals P (Ca-P), using MgCl 2 , NaOH + NaCO 3 , and HAc + NaAc as extractants, respectively [28].…”

Section: Sampling and Analysismentioning

confidence: 99%

Phosphorus Release from Sediments in a Raw Water Reservoir with Reduced Allochthonous Input

Zhou

Fu²,

et al. 2021

Water

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Following successful abatement of external nutrient sources, one must shift the focus to the role of phosphorus (P) release from sediment. This enables us to better assess the causes for sustained eutrophication in freshwater ecosystem and how to deal with this challenge. In this study, five sediment cores from the shallow YuQiao Reservoir in northern China were investigated. The reservoir serves as the main raw water source for tap water services of Tianjin megacity, with a population of 15.6 million. Sediment characteristics and P fractions were determined in order to assess the role of the sediments as the P source to the water body. The total P content (TP) in sediments was similar to what was found in catchment soils, although the P sorption capacity of sediments was 7–10 times greater than for the catchment soils. Isotherm adsorption experiments documented that when P concentration in overlying water drops below 0.032–0.070 mg L−1, depending on the site, the sediment contributes with a positive flux of P to the overlying water. Adsorbed P at different depths in the sediments is found to be released with a similarly rapid release rate during the first 20 h, though chronic release was observed mainly from the top 30 cm of the sediment core. Dredging the top 30 cm layer of the sediments will decrease the level of soluble reactive phosphate in the water being sustained by the sediment flux of P.

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An Automated Method for the Determination of Orthophosphate in the Presence of Labile Polyphosphates

Cited by 23 publications

References 0 publications

The effects of phosphorus and form of nitrogen supply on leaf cell size and nutrient content in Trifolium repens and Lotus uliginosus

The effects of phosphorus and form of nitrogen supply on leaf cell size and nutrient content in Trifolium repens and Lotus uliginosus

Phosphorus fractions in trifoliate leaves of white clover and lotus at various levels of phosphorus supply

Phosphorus Release from Sediments in a Raw Water Reservoir with Reduced Allochthonous Input

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