Photometric Analysis of Phosphate Rock

Barton, C. J.

doi:10.1021/ac60023a024

Cited by 234 publications

(102 citation statements)

References 10 publications

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“…Ilf the rate constants k1 and k, are large in relation to k3 (9) and the reaction is essentially irreversible (5), which is consistent with our data, then Km is approximately equal to a dissociation constant and 1 …”

Section: Methodssupporting

confidence: 89%

Effects of Temperature on Orthophosphate Absorption by Excised Corn Roots

Carter¹,

Lathwell²

1967

Plant Physiol.

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Summary. The uptake of orthophosphate (32P) by excised corn roots, Zea mays L.was studied using roots grown on 0.2 mm CaSiO4. Nine concentrations of KH2PO4 from 1 to 256 /uM were used at temperatures of 200, 300, and, 400. Enzyme kinetic analysis was applied to the data obtained. Two apparent mechanisms (sites) o,f phosphate uptake were observed, 1 dominating at high P concentrations and 1 at low P concentrations. A Km of 1.36 X 10-4 and; a Vmax of 177 X 10-9 moles per gram of roots per hour at 300 was calculated for the mechanism dominating at high P concentrations. Similar calctlations gave a Km of 6.09 X 10-6 and-a Vmax of 162 X 10-9 moles per gram of roots per ihour at 300 for the mechanism dominating at low P concentrations. The Qlo for both mechanisms was approximately 2. Calculation of thermodynamic values from the data gave AF of -5200 cal, AH of -950 to -1400 cal, and a enthalpy of activation (A) of 10,300 to 13,800 cal per mole for the mechanism dominating at high P concentrations. Similar calculations from the data for the mechanism dominating at low P concentrations gave a AF of -7300 cal, AH of -10,700 to -8200 cal, and a A of 9300 to 18,900 cal per mole. If the dual mechanism interpretation of this kind of data adequately describes this system, then both mechanisms of P absorption by corn roots involve chemical reactions.Kinetic studies 'have lead to the postulation of a number of rather precise relationships with respect to the mechanism of phosphate uptake by excised barley roots (10, 14, 15). Most significant has been the interpretation that 2 apparent sites or mechanisms of P absorption are involved. The dual mechanism data have been initerpreted to imply separate sites for the absorption of the 2 phosphate ionic species, H2PO,9). Likewise, the enhancement of Ca2+ on P uptake is an important observation. The effect of temperature on absorption of orthophosphate by excised corn roots from solutions of a wide range of phosphate concentrations was examined to test the hypothesis that the apparent dual mechanism of phosphate uptake may be due to the combined action of physical and metabolic components. Enzyme kinetic analysis was applied to the data obtained and certain thermodynamic values were calculated. Materials and MethodsSeeds of Zea mays L, var. OH10 X 51A X B8, supplied by the Department of Plant Breeding, Cornell University, were placed on pa-per towelling covering a 1.5 cm layer of acid washed sand in 33 X 22 cm pyrex baking dishes. The sand was moistened with 0.2 mnm CaSO4. Dishes were covered with saran wrap (punctured for aeration) and placed in an incubator in the dark at 230 for 90 to 95 hours.Roots (approximately 6.5 cm long) were cut off adjacent to the seed, blotted dry, and weighed into ,lots of approximately 1 gram for each treatment.They were then placed into 500 ml wide mouthed jars containing 0.2 mm CaSO4 and aeration tubes. The jars were placed in a temperature controlled water bath and allowed to come to equilibrium for 30 minutes. The CaSO4 solution was removed by suctio...

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Section: Methodssupporting

confidence: 89%

Effects of Temperature on Orthophosphate Absorption by Excised Corn Roots

Carter¹,

Lathwell²

1967

Plant Physiol.

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“…After being ground, samples were dryashed at 500°C for 5 h and dissolved in 3.3% HCl solution. Analysis was carried out for K, Ca, Mg, Fe, Mn, Zn, and Cu using atomic absorption spectrometry (Varian FS 220) and for P following the method of Barton (1948).…”

Section: Introductionmentioning

confidence: 99%

Response of four grapevine (Vitis spp.) genotypes to direct or bicarbonate-induced iron deficiency

Sabır

Bilir-Ekbic

Erdem

et al. 2010

Span. j. agric. res.

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In Turkey, calcareous soil conditions usually cause signif icant decreases in grape yield. Understanding the physiological responses of grapevine genotypes under such conditions would yield invaluable knowledge to recover these problems. This study was thus conducted on the comparative evaluation of the responses of four Vitis spp. materials (a cultivar, 'Alphonse Lavallee', and three rootstocks, 'Fercal', '99 R' and '1613 C'), differing in tolerance potential to direct and lime-induced chlorosis. In greenhouse, rooted cuttings were grown in inert perlite using containers for two years with complete Hoagland nutrients solution except for Fe as variable. The experiment comprised five applications performed for three times per year. Iron applications (FeNaEDTA) in 9 and 36 mg L -1 doses and their combinations with 840 mg L -1 NaHCO 3 were compared with control (iron-free Hoagland solution).

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“…Hence a study of the estimation process was done whereby the preconcentration of Fe and PO4 ions was carried out by the protonation of the samples using various concentrations of HCl and sulphuric acid. The use of sulphuric acid and hydrochloric acid in the estimation of PO4 and Fe respectively is traditional [27][28][29][30][31][32][33] but our experiments confirmed that the concentration of acids used in the conventional methods is insufficient to break the strong Fe-O-P bond as hydrochloric acid used is mostly for acid hydrolysis in the estimation of iron. Fe from various sources like plant body, the human body, drinking water or any other source is estimated by using HCl for the process of acid hydrolysis.…”

Section: Resultsmentioning

confidence: 60%

INVESTIGATION AND ALLEVIATION OF MUTUAL INTERFERENCE OF Fe2+AND PO43-IONS BY PROTONATION

2017

RJC

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Mutual interference of iron and phosphates in the spectrophotometric estimation process is a result of the strong bond in the iron phosphate complex. The interference of these two ions can be successfully overcome by the isolation of the two ions. The present investigation was carried to study the mutual interferences of iron and phosphates in the spectrophotometric analysis. Complexing both Fe and PO4 ions in the form of Fe-P complex were done for isolating the Iron and phosphate radicals from other interferences. Whereas to avoid the interference of Fe in PO4 estimation, AlPO4 complex was formed. This triggered the idea to pre-concentrate the two ions by protonation using a strong acid. The results obtained justified the need for isolation of Fe 2+ and PO4 3-.This study provides an exact estimation of Fe 2+ at pH 1.5. The results obtained were statistically correlated by Pearson's correlation coefficient and the results were statistically significant at p value 0.01.

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Photometric Analysis of Phosphate Rock

Cited by 234 publications

References 10 publications

Effects of Temperature on Orthophosphate Absorption by Excised Corn Roots

Effects of Temperature on Orthophosphate Absorption by Excised Corn Roots

Response of four grapevine (Vitis spp.) genotypes to direct or bicarbonate-induced iron deficiency

INVESTIGATION AND ALLEVIATION OF MUTUAL INTERFERENCE OF Fe2+AND PO43-IONS BY PROTONATION

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