Effect of drought stress and re-watering on the morphological characteristics of root, stem, and leaf in Helianthus tuberosus

Using pot experiments, we examined the effects of drought stress and re-watering on root, stem, leaf, stem/leaf ratio, root/shoot ratio, and biomass in Helianthus tuberosus The following results were obtained. Root, stem, leaf biomass, and total biomass in treated plants were lower than those in control plants. The diameter of the taproot and fibrous roots was increased. During drought stress and re-watering, the lengths of fibrous roots were greater than those in control plants, and the length of the taproot was greater than the control during drought stress but lower than the control during re-watering. The mean leaf area of treated plants was higher than that of control plants, and the number of leaves were lower than that in control plants. The stem/leaf ratios of treated plants were all higher than those of control plants, except on the second day of measurement. During drought stress and re-watering, the root/shoot ratio of treated plants under drought stress on the second day of measurement and re-watered plants at 16 days was higher than that of the control plants, but lower than that of control plants on the fourth and eighth days under drought stress and eighth day under re-watering.