REGENERATION OF PLANTLETS FROM PETIOLE CALLUS OF WILD VIOLA (VIOLA-PATRINII DC)

Plantlets were regenerated from 5-year subcultured compact callus deri ved from petiole tissues of wild viola (Viola patrinii DC.) but not fr om 5-year subcultured friable callus. Regeneration occurred most effic iently on medium that contained two-fold diluted basal salts of Murash ige and Skoog's (MS) medium, 5 x 10(-6) M 1-naphthaleneacetic acid and 10(-6) M kinetin. The effect of dilution of RIS basal salts could als o be achieved solely by two-fold dilution of the potassium dihydrogen phosphate in the mixture. The present study revealed that dilution of MS basal salts, in particular of potassium dihydrogen phosphate, was i mportant for the regeneration of wild viola. Moreover, although the ca llus had been subcultured for 5 years, regeneration of plantlets from callus was still possible. In addition, scanning electron microscopy r evealed that details of the process of plant regeneration from subcult ured callus varied with the age and source of callus and differed from that reported in rice.