The role of antioxidants for initiation of somatic embryos with Conostephium pendulum (Ericaceae)

Using Conostephium pendulum as a ‘model’ species in the Ericaceae a study was instigated to investigate the role ofoxidative stress on the embryogenic competency of the explant tissue and callus. Three antioxidantswere examinedas an explant pre-treatment and incorporated in the growth medium. Pre-treatment of explant tissues with tripotassiumcitrate and citric acid significantly reduced callus necrosis, however this treatment significantly reducedsomatic embryo production when compared to preparing tissue under sterile distilled water. A combination of tripotassiumcitrate and citric acid incorporated in the medium significantly reduced phenolic browning, however thistreatment had no significant effect on the number of somatic embryos formed suggesting that prevention of tissuebrowning may be feasible by reducing the contact with oxygen during excision of tissues.