Nitrogen Uptake and Plant Growth II. An Empirical Model of Vegetative Growth and Partitioning

Abstract

An empirical model of vegetative plant growth is presented. The model is based on experimental data on Polygonum cuspidatum, which showed (1) that the partitioning of dry matter and nitrogen among organs was linearly related to the nitrogen concentration of the whole plant and (2) that leaf thickness was negatively correlated with leaf nitrogen concentration. The model properly describes the behaviour of plants. Steady-state solutions of the model give the relative growth rate, specific leaf weight, and partitioning of dry matter and nitrogen among organs with the net assimilation rate and the specific absorption rate as environmental variables. The effect of nitrogen removal on dry matter and nitrogen partitioning was examined as non-steady-state dynamic solutions of the model. The model predicted not only reduced leaf growth and enhanced root growth but also a flux of nitrogen from the leaf to the root, which agreed with the experimental results.