Callus Induction in the Liverwort Asterella wallichiana (L. et L.) Grolle

Thalli of Asterella wallichiana develop normally on Nitsch's basal medium. On Murashige and Skoog's medium containing 2% sucrose callus arises either on the periphery or on the entire surface of the inoculum. Histological studies reveal that callus develops from the upper epidermis and the underlying 3 or 4 layers or at times from all parts of the thallus. Macro elements of the MS medium, sucrose (2 %) and growth regulators (IAA and kinetin) are essential for callus induction. Vitamins of this medium reduce callus growth as well as the percentage of response of cultures. Callus growth is slightly accelerated by incorporating ferric citrate in place of chelated iron.