Somatic embryogenesis is induced commonly using the auxin:
Somatic embryogenesis induction most frequently relies on auxin 2,4 dichlorophenoxyacetic acid 2,4-D applied at 0.5 to 10 mg per L because this synthetic phenoxy auxin resists degradation by IAA oxidases maintains prolonged auxinic signaling. High 2,4-D imposes stress and auxin response causing differentiated somatic cells to re-enter cell division and acquire totipotency through global epigenetic reprogramming involving DNA demethylation histone acetylation and activation of chromatin remodeling factors. It stimulates expression of embryogenic competence markers SERK1 glutathione S transferas
Ref: Dudits et al., J Exp Bot 2011 2,4-D embryogenesis; NCBI Book somatic embryogenesis.
