Modeling phosphorus uptake and utilization by plants

Amijee, F. and Barraclouch, P.B. and Tinker, P.B. (1991) Modeling phosphorus uptake and utilization by plants. In: Phosphorus nutrition of grain legumes in the semi-arid tropics. International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Andhra Pradesh, India, pp. 63-75. ISBN 92-9066-200-X

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The uptake processes of phosphorus (P) from soil are complicated by the fact that it is a highly immobile element, and transport through soil to the root surface is often a rate-limiting step. The difficulties are enhanced by the dependence of the diffusion coefficient upon the soil type, P concentration, and soil moisture content. A model for P uptake from soil is therefore basically a diffusion model for an irregularly distributed sink in a medium of variable diffusion coefficients. The dynamic nature of the process, in that the root system is constantly growing and developing, also has to be taken into account. Finally, there are modifications of the root that have a strong bearing on its ability to take up Pfrom the soil. These include uptake by root hairs, local pH changes in the rhizosphere, effect of root exudates, and vesicular-arbuscular mycorrhizal (VAM) associations. The approach towards a model ofP uptake must therefore be gradual, with steadily increasing levels of sophistication and complications being introduced. The earliest models were for artificial arrangements using planar geometry. Other models dealt essentially with single roots, in that they ignored any interaction between roots. More complex models that included the growth of the whole plant were later developed. This work showed that in many soil conditions, particularly when the plant was P-deficient, the restriction on uptake lay almost entirely upon P supply and transport in the soil, and not with the root uptake properties. The success of some simple models is surprising, when the real complications in the rhizosphere processes are considered.

Item Type: Book Section
Author Affiliation: Division of Bacteriology, School of Agriculture,University of Aberdeen, 581 Kang Street, Aberdeen AB9 1UD, UK
Subjects: Plant Physiology and Biochemistry > Biochemistry
Divisions: Other Crops
Depositing User: Sandhya Gir
Date Deposited: 25 Apr 2011 07:42
Last Modified: 25 Apr 2011 10:19

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