TISSUE-CULTURE OF RANUNCULUS-LYALLII HOOK F

A micropropagation method is presented for Ranunculus lyallii Hook. f. Seedling establishment in culture required surface sterilisation of t he achene, followed by dissection of the embryo from the other tissues of the seed. This process was necessary both to avoid the persistent presence of the fungus Botrytis cinerea and to overcome physiological dormancy. Seedlings germinated and grew well on an agar-solidified bas al medium comprising half-strength Murashige and Skoog (MS) salts (Mur ashige & Skoog 1962), MS organics, and 3% sucrose. Shoot proliferation increased with increasing 6-benzylaminopurine (BAP) concentration up to 0.6 mg/litre, whereas higher rates caused shoot distortion and inhi bited subsequent rooting of plantlets. Shoot proliferation was optimis ed on basal medium supplemented with 0.2 mg/litre BAP. Root formation was completely inhibited by BAP, even at 0.1 mg/litre, the lowest conc entration tested. Adding 0.1-0.5 mg/litre indole-3-butyric acid (IBA) to the medium had no effect on this response. As shoots readily formed roots on the basal medium without additional growth regulators, this formulation was used for rooting in all subsequent manipulations.