Abstract
Characteristics of root growth in root vegetables raised in hydroponics were studied. Radish (Raphanus sativus), carrot (Daucus carota) and gobo (Arctium lappa) were cultured with the deep flow culture technique (DFT) or the ebb and flood culture (E & F) technique with or without substrate. Seedlings of which the tap root was straight and had started thickening were transplanted in the hydropoic system. Individuals were obtained in all the crops studied, the root of which attained the size and shape proper to each cultivar. Storage root growth with DFT was rather inconsistent as compared to that with E & F with or without substrate, especially in radish. Increase in both root diameter and length along the root axis contributed to storage root growth of radish, while very little increase in root length was observed in carrot. Root length decreased as root diameter increased during storage root growth of gobo. Increase in root diameter toward the proximal end of carrot storage root was remarkable with DFT, resulting in a spindle shape of the root and was often followed by radial cracking along the axis. This phenomenon was observed also in radish to a lesser degree. Results of present study demonstrated that satisfactory growth of storage root in root vegetables could be obtained in hydroponics, although characteristics of growth were different in several aspects in the three vegetables studied.
