Enhancement of somatic embryogenesis in orchardgrass leaf cultures by epinephrine

Epinephrine at 10–100 μM stimulated somatic embryogenesis from orchardgrass (Dactylis glomerata L.) leaves cultured on SH medium with 30 μM of indole-3-acetic acid (IAA). Ethylene emanation was increased at epinephrine concentrations greater than 10 μM. Decarboxylation by the leaves of [1-14C]IAA included in the medium was decreased almost 3-fold by 10 μM epinephrine. Epinephrine at 10 μM enhanced the number of regenerated plants on SH medium with 30 μM dicamba (SH-30). Ethylene emanation was increased by epinephrine concentrations of 500 μM and greater included in SH-30 but somatic embryogenesis was decreased. Addition of 8 μM CoCl2, 6H2O (an ethylene biosynthesis inhibitor) to medium with 500 μM epinephrine decreased ethylene emanation to the control level but did not alleviate the decreased embryogenic response.