P accumulation

The growth of ectomycorrhizal trees is frequently improved by their increased phosphorus (P) accumulation (3), and this, in turn, is related to the intensity of the mycorrhizal infection. Ectomycorrhizal fungi solubilize insoluble forms of A1 and Ca phosphates as well as inositol hexaphosphates, though a wide interstrain variability has been recorded (112). These complex P forms are digested by the secretion of extracellular acid and alkaline phosphomono- and phosphodi-ester-ases. Pi in soil solutions is easily taken up by ectomycorrhizal hyphae and then translocated to the host roots. Its absorption and efflux are probably regulated... 

Han F.X., Kingery W.L., Selim H.M., Gerald P. Accumulation of heavy metals in a longterm poultry waste-amended soil. Soil Sci 2000 165 260-268. 

Deficiency of galactose 1-phosphate uridyltransferase produces a more severe disease because, in addition to galactosemia, galactose 1-P accumulates in the liver, brain, and other tissues. The two enzyme deficiencies are compared in Table 1-12-3. 

Cyclic voltammetric, oxidation of P+ accumulated at Nafion-SPCE Cyclic voltammetric, oxidation of product at cation-exchanger-doped SPCE 1-Naphthol, amperometric... 

R4. Ransom, J. T., and Reeves, J. P., Accumulation of amino acids within intracellular lysosomes of rat polymorphonuclear leukocytes incubated with amino acid methyl esters. Evidence for the internal acidification of azurophilic granules. J. Biol. Chem. 258, 9270-9275 (1983). 

Polomski, J., Fluhler, H., and Blaser, P, Accumulation of airborne fluoride in soils, J. Environ. Qual., 11, 457, 1982. 

Erkkila AT, Lehto S, Pyorala K, Uusitupa MI. n-3 fatty acids and 5-y risks of death and cardiovascular disease events in patients with coronary artery disease. Am. J. CUn. Nutr. 2003 78 65-71. He K, Song Y, Daviglus ML, Liu K, Van Horn L, Dyer AR, Greenland P. Accumulated evidence on fish consumption and coronary heart disease mortaUty a meta-analysis of cohort studies. Circulation 2004 109 2705-2711. 

Enzyme kinetics are more easily approached if we can ignore the back reaction. We define E q as the rate of increase in product with time when [P] is low that is, at times close to zero (hence, Vg) (Figure 813B). Thus, for the graph in Figure 8.11. F g is determined for each substrate concentration by measuring the rate of product formation at early times before P accumulates (see Figure 8.12). 

Brossard J-H, Cloutier M, Roy L, Lepage R, Gascon-Barre M, D Amour P. Accumulation of a non-(l-84) molecular form of parathyroid hormone (PTH) detected by intact PTH assay in renal failure importance in the interpretation of PTH values. J Cfin Endocrinol Metab 1996 81 3923-9. 

Table 1. The rates (molT s1) of PEH and P accumulations (P = AC+MPC ) in the presence of systems Fe(III)(acac)3 + R4NBr(L2) without admixed H20 (L3) and at the addition of small amounts of H20 (3,7-10 3.mol/l)...

The term d[P j,]/dt is calculated assuming that the concentration of phosphorus in all decomposing litter is 0.16 mmol 1110 . This is based on the 68% retranslocation of P from leaves and fine roots and the average branch, bole, and coarse root P concentrations (Sec. 3.2). Where the sensitivity of the model to P accumulation in the microbial carbon pool is tested, based on data summarized by Gijsman et al. (1996) we use a tissue P concentration for microbes of 6.4 mmol P moG C. In all simulations, it is assumed that soil phosphorus mineralization proceeds with a rate constant of 0.5 year , with phosphorus mineralization proceeding independently of carbon mineralization. This is on the basis of the evidence discussed in Sec. 2.1. Indeed, inflexible soil carbon pool C/P ratios which effectively link phosphorus mineralization rate to the carbon mineralization rate in models such as CENTURY (Parton et al, 1988) have been strongly criticized by some tropical soil chemists (Gijsman et al, 1996). 

Averaging across regions with varying P accumulation rates undoubtedly imparts a relative error of at least 50% to the burial rate value derived here. Also, some restricted environments exhibit quite high but spatially variable P burial rates (e.g., phosphatic continental margin environments, Froelich et al. 1982 hydrothermal iron sediments, Froelich et al. 1977, Wheat et al. 1996). The areal approach is a more direct route to quantifying the burial terms in the P mass balance, and indicates that reactive P burial in continental margin sediments accounts for about 60% of the oceanic output, with deep sea sediments nearly equivalent as a sink. 

Figure 5. (a) P concentration and (b) percent of total P for each P-bearing fraction in sediments from Jackson Pond, (c) Accumulation rate of P fractions at Jackson Pond, (d) Total P accumulation rate at Anderson Pond and Jackson Pond. age-control points for Jackson Pond (Wilkins et al. 1991) are shown as arrows on age axis in (a). Lowermost point is 20,330 yr. age-control points are also shown for Anderson Pond (Delcourt 1979, Mills and Delcourt 1991) as arrows in (d). Lowermost point is 25,000 yr. The nonoccluded fraction (Fig. 2) is small and is combined with the occluded fraction in this analysis. 

Wetlands and aquatic systems are recipients of phosphorus loads from upland systems. Increased loading of phosphorus to a system can cause nitrogen limitations. The phosphorus enrichment of P-limited systems leads to eutrophication and ecosystem stress. The phosphorus cycle does not have a significant gaseous loss mechanism. Thus, most of the added P accumulates in the systems. 

Table 4.14. The area, mass accumulation rate, P total concentration, P accumulation rate, and P burial flux for each box of the ECS (Fang et al., 2007) (With permission from Elsevier s Copyright Clearance Center)...

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