Response of plant roots to elevated atmospheric carbon dioxide

ABSTRACT Plant root response to atmospheric CO 2 enrichment can be great. Results from this controlled environment investigation demonstrate substantial effects on root system architecture, micromorphology and physiology. The most pronounced effects were an increase in root length (110%) and root dry weight (143%). Root diameter, stele diameter, cortex width, root/shoot and root weight ratios all increased; root numbers did not increase. The long‐term implications for belowground processes could be enormous.