EFFECT OF PHYTOHORMONES ON PLANT-REGENERATION FROM CALLUS OF GLADIOLUS CULTIVAR JENNY-LEE

Callus capable of plant regeneration was initiated at a higher frequen cy from the basal leaves of in vitro plants (70% explants) as compared to cormel slices (30% explants) when cultured on medium containing va rious concentrations of auxin. The greatest number of plants were rege nerated from 4-mo.-old callus (112 plants/g fresh weight callus) cultu red on medium containing 10 mg/liter (53.8 mu M) 1-naphtaleneacetic ac id. The addition of 2 mg/liter (9.3 mu M) kinetin to a Murashige and S koog's basal salts regeneration medium resulted in a average two- to t hree-fold increase in the number of plants regenerated compared to reg eneration on medium without hormones. Ten months after callus initiati on, all callus maintained on auxin-supplemented media showed a drastic reduction in its capacity to regenerate plants. Ten-month-old callus maintained on dicamba regenerated the greatest number of plants (14 to 23 plants regenerated per gram fresh weight callus) as compared to ca llus maintained 10 mo. on medium containing 1-napthaleneacetic acid or 2,4-dichlorophenoxyacetic acid. Cormel slices cultured on cytokinin-s upplemented media formed small amounts of callus which regenerated up to 19 plants per cormel slice within 1 to 2 mo. after the cormel slice had been placed on either 10 mg/liter (49.2 mu M) N-6-2-isopentenylad enosine or 1 mg/liter (4.4 mu M) 6-benzylaminopurine.