We discovered the super growing roots (SR) from Lotus corniculatus L., which grows efficiently after removing the above-ground organs and cultured in a medium containing no plant hormone (Akashi et al. 1998). This root possesses high regeneration competence. Also, protoplasts can be extracted easily and these protoplasts show a vital proliferation. These characteristics are maintained until now after 5 years have passed since the discovery (Akashi et al. 1998, 2000). The SR can be used in physiological researches of the root, and also in functional analysis of genes by transformation.