Differential expression of phosphoenolpyruvate carboxylase isoforms in calli induced from C3 and CAM types of L-Mesembryanthemum crystallinum

Crassulacean acid metabolism (CAM)-specific phosphoenolpyruvate carboxylase (PEPC) isoforms were first detected in the callus of Mesembryanthemum crys tallinum. The present study was undertaken to clarify the effects of NaCl a nd abscisic acid (ABA) in relation to the photosynthetic origin of calli (i nduced from C3 or CAM M, crystallinum plants) on the PEPC isoform pattern. The CAM-specific PEPC isoforms appeared in calli induced from CAM leaves un der NaCl treatment but not in calli from C3 leaves, or under ABA treatments . We conclude that: (a) calli from C3 and CAM leaves partially maintain cha racteristics of their physiological history and do not completely revert to an embryonic state; (b) ABA and NaCl elicit different responses.