ISOLATION AND CULTURE OF MESOPHYLL PROTOPLASTS FROM ROSA-HYBRIDA

After I h plasmolysis in CPW13M solution, highly viable (>75%) protopl asts were isolated from leaves of axenic shoot cultures of Rosa hybrid a L. cv. Abraham Darby using an enzyme mixture containing 1.0% (w/v) H emicellulase, 0.1% (w/v) Macerozyme, 1.0 (w/v) Cellulase RS, 0.05% (w/ v) Pectolyase Y23 and 1.0% (w/v) PVP-10 and from cv. Marie Pavie using an identical mixture but with Cellulase RS and Pectolyase Y23 at 0.7% (w/v) and 0.1% (w/v), respectively. With both cvs., sustained protopl ast division was achieved after plating in agarose beads with modified KM8p medium containing 1.0% (w/v) polyvinylpyrrolidone (mel. wt. 10 0 00; PVP-10), 8.91 mu M naphthaleneacetic acid (NAA) and 4.44 mu M 6-be nzyladenine (BA). Protoplast-derived callus gave rise to roots after t ransfer to SH medium containing 14 mu M 2,4-D.