Plant regeneration from tissue cultures of many species has been reported so far, but various groups. families and genera are still regarded as recalcitant, and tools susceptible to distinguish as early in culture as possible the regeneration-competent cells and tissues from those that will never regenerate would be of interest, whatever the regeneration pathway We have examined various cytological parameters to identify those that might serve as early indicators of cell competence to undergo somatic embryogenesis and/or organogenesis Water potential of the culture medium declined preceding the onset of embryogenesis while intracellular osmolarity and cell sui face increased concomitantly in embryogenic cells In addition, cellulose accumulated us the walls of non-embryogenic cells while cell walls became thinner with onset of embryogenesis, and diminished further as embryos matured In parallel experiments, rise cytogenetic, proteomic and molecular processes governing the competence for embryogenesis and/or organogenesis from plant cells were studied with Arabidopsis thaliana, and more recently also with Medicago truncatula and pea, both by flow cytometry, immunocytohistology, mono and bidimensional electrophoresis and comparing insertion mutants and RNA(is) with their respective wild types The implications of these results when applying biotechnology approaches for grain legume breeding, and in terms of plant regeneration competence in general arc discussed.