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-(14)C]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.