Alcohol dehydrogenase (EC 1.1.1.1) isozymes as markers at 2,4-dichlorophenoxyacetic acid x kinetin combinations in callus cultures of Cereus peruvianus (Cactaceae).

Alcohol dehydrogenase (ADH; EC 1.1.1.1) isozymes were investigated in tissue of Cereus peruvianus cultured in different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin. Five ADH isozymes were detected in starch gel and showed different patterns in seeds, seedlings, calli cultured at 32 and 22 degrees C, and plants regenerated from calli cultured in three 2,4-D and kinetin combinations. Four phenotypes formed by different combinations of ADH-2, ADH-3, ADH-4, and ADH-5 were detected in calli cultured at 32 degrees C and in plants regenerated from calli. ADH-1 isozyme was detected only in calli subcultured for 1 or 2 weeks at 22 degrees C and was indicated as a marker of stress conditions that affect the growth of C. peruvianus callus tissues in culture. ADH phenotypes with either a higher or a lower number of isozymes were detected in different proportions in the callus tissues cultured in media containing different 2,4-D and kinetin ratios. ADH isozyme patterns were found to be sensitive markers at the highest kinetin concentration or at high kinetin/2,4-D ratios. The results indicate a high correlation between the ADH isozyme patterns and the capacity for regeneration. Thus, ADH isozymes are indicated as good biochemical markers and as a powerful tool for monitoring studies of C. peruvianus callus cultures.