Characterization of Horseradish Hairy-Root Clone Depressing Differentiation of Adventitious Shoots

Horseradish (Armoracia rusticana) hairy-root clones AR182 and AR450 were used to examine the capabilities for differentiation of adventitious shoots from root segments. When horseradish hairy roots were cultured in phytohormone-free LS medium in the light condition, adventitious shoots were formed in AR450 but not formed in AR182. To elucidate effects of phytohormones on differentiation of adventitious shoots in AR182, hairy roots were cultured in LS medium containing naphthaleneacetic acid (NAA) and benzyladenine (BA) in the light condition. A large number of adventitious shoots were formed in LS (10-6M NAA) and LS (10-7M NAA and 10-7 M BA) in AR450. But adventitious shoot was not formed in AR182 even in the presence of NAA and BA. These results showed that the adventitious shoot formation was strongly repressed in AR182.