MANNITOL AND THIDIAZURON IMPROVE IN-VITRO SHOOT REGENERATION FROM SPEARMINT AND PEPPERMINT LEAF-DISKS

In vitro shoot organogenesis of peppermint and spearmint was obtained from leaf disks. Regeneration occurred within six weeks of placement i n culture. Best results were obtained when explants were cultured for two weeks onto Murashige and Skoog medium supplemented with 300 mM man nitol, 2.0 mu M 6-benzyladenine and 2.0 mu M indole-3-butyric acid, an d then transferred on a medium without mannitol and containing 0.5 mu M cr-naphthaleneacetic acid, 9.0 mu M 6-benzyladenine and 0.5 mu M thi diazuron. Using these culture conditions, percentages of regeneration were 78% for peppermint and 49% for spearmint. Because of its efficien cy, this leaf disk regeneration method could be a suitable tool for ge netic transformation with Agrobacterium tumefaciens.