Comparative effect of different types of cytokinin for shoot formation and plant regeneration in leaf-derived callus of lavender (Lavandula vera DC)

Leaf-derived calli of Lavandula vera DC were cultured on Murashige and Skoog (MS) solid medium supplemented with purine or urea-type-cytokinins at 25 degrees C under continuous light conditions. When calli were cultured on the medium with 6-benzylamino purine (BA) at 4.4 x 10(-7) -4.4 x 10(-5) M, shoots were formed on green spots appearing on the callus surface; the highest value for shoot formation rate was 55.3% at 4.4 x 10(-6) M. In the medium with thidiazuron (TDZ) or N-(2-chloro-4-pyridyl) -N'-phenylurea (CPPU), green spots were not observed, but callus surface turned compact and greenish. Only multiple shoots were formed at all the concentration regimes. CPPU at 4.0 x 10(-7) M was most effective for multiple shoot formation, 52.0%. Most shoots obtained in the presence of BA. formed vigorous roots in 1/2 MS medium with or without 3-indolebutyric acid (IBA) at 9.9 x 10(-7) M. Plantlets could be easily acclimatized in a greenhouse. On the other hand, multiple shoots obtained when using TDZ or CPPU could not form any root and died during the culture period. (C) 1999 Elsevier Science B.V. All rights reserved.