INVITRO REJUVENATION OF BETULA (BETULACEAE) - BIOCHEMICAL EVALUATION

The pattern of protein production during rejuvenation of in vitro cultured Betula was determined. Comparisons were made between half-sib seedlings and micropropagated, grafted, and cutting-propapted mature-phase birch grown under similar conditions. Three clones were examined at 1, 4, and 8 mo postpropagation, for differences in total denatured protein and peroxidase and esterase isozymes. Polyacrylamide gel electrophoresis was employed to produce protein banding patterns representative of each type of plant at each time postpropagation. Evaluation of total denatured protein banding patterns indicated that micropropagated plants are initially more like seedlings than mature plants. Peroxidase and esterase isozyme analyses detected differences in isozyme activity and composition between the variously propapted plants and supported evidence provided from the denatured protein patterns. The type of plant part that is evaluated is critical in determining if isozyme banding patterns can be seen. Specific proteins or enzymes that mediate phase change in birch could not be detected consistently between clones or tissue types.