The Uptake of Potassium, Nitrate, Water, and Oxygen by a Maize Root System in Relation to its Size

Abstract

Using a special apparatus, the uptake of nitrate, potassium, water, and oxygen by a maize plant was recorded at short intervals. After cutting most of the roots, the regrowth of the root system was measured in relation to the increase in nitrate, potassium, and water uptake, oxygen consumption of the root system, and leaf growth rate. It has been suggested that when the root surface is not limiting nitrate reduction is the rate-limiting process for nitrate uptake. Differences between nitrate uptake in light and dark are explained by the influence of light on nitrate reduction. Differences in leaf growth rate have been discussed in relation to root resistance and leaf water content.