Quantitative estimation of root exudation of maize plants

Abstract

The rate of root exudation of maize plants was estimated by measuring the rate of denitrification in a hermetically sealed root system. While CO2 production measured in the rhizosphere results both from root respiration and microbial respiration N2O production during nitrate respiration is solely related to the amount of root exudates available for bacterial degradation. With 4 week old plants growing in quartz sand or soil root exudation amounted to 7% of the net photosynthates. Calculations revealed that about 25% of the organic matter flowing into the root system was excreted into the rhizosphere.