Root cortex structure and metabolic responses of Spartina patens to soil redox conditions

Abstract

Under controlled rhizotron oxidation-reduction conditions, roots of Spartina patens (Ait) Muhl. were subjected to low soil redox potentials. Root elongation was inhibited by root hypoxia resulting from low soil oxidation-reduction and there was a substantial change in root cortex structure. Studies on root anatomy indicated that low soil oxidation-reduction resulted in a dramatically changed cellular structure in the cortex but not in the vascular cylinder. Alcohol dehydrogenase activity in the roots was increased by approximately three times that of control plants, an indication of acceleration in fermentation. Results suggest that in coastal marshes, S. patens requires periods of drainage or less reducing soil conditions during the growing season for root penetration into otherwise anaerobic zones of the soil-root profile.