Abstract

In vitro shoot induction from callus and direct bulbil formation from shoots were obtained in Leucocoryne purpurea, an endemic vulnerable Chilean species. Basal leaf portions, bulb basal plate and root tips from in vitro grown plants were used as explants. Only bulb basal plate explants displayed morphogenic responses. Callus, shoot and bulbils developed on MS basal medium in the presence of various growth regulator combinations. Callus formation from bulb basal explants ranged between 40 to 100%; the highest response was observed in the presence of 4.5 or 13.6 µM 2,4-D alone or 4.5 µM 2,4-D in combination with 0.5 µM BA after 4 months. Picloram alone or in combination with 2iP or BAP also supported callus initiation. Indirect shoot formation from callus occurred only after a further culture period of 2 months in MS medium containing 0.5 or 2.3 µM TDZ. Basal bulb plate explants cultured in the presence of TDZ alone (0.5 and 2.3 µM, respectively) exhibited direct shoot formation within 90 days. After subculture in the presence of 0.5 µM TDZ each single shoot formed new shoots (3 to 4) and new bulbils. However higher TDZ levels, up to 2.3 µM, produced shoots with roots only, inhibiting bulbil formation, and the 4.5 µM TDZ concentration caused necrosis.