Elevated Root-Zone Temperature Modulates Growth and Quality of Hydroponically Grown Carrots

Abstract

Air and soil temperatures strongly influence the growth and quality of crops. However, in root vegetables, such as carrot, few experiments aimed at regulating growth and quality by manipulating root-zone temperature have been reported. We investigated the effect of root-zone temperatures (20˚C, 25˚C, 29˚C, and 33˚C) on carrot growth and components using a hydroponic system. High root-zone temperatures for 14 days reduced shoot and rootgrowth and water content. In contrast, total phenolic compounds and soluble-solid content increased in tap roots under high-temperature treatment. Root oxygen consumption was upregulated after 7 days under high-temperature treatment. These results suggest that high root-zone temperatures induce drought-like stress responses that modulate carrot biomass and components. High root-zone temperature treatments administered to hydroponically grown crops may be a valuable tool for improving and increasing the quality and value of crops.