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 of oxidative stress on the embryogenic competency of the explant tissue and callus. Three antioxidants were examined as an explant pre-treatment and incorporated in the growth medium. Pre-treatment of explant tissues with tri-potassium citrate and citric acid significantly reduced callus necrosis, however this treatment significantly reduced somatic embryo production when compared to preparing tissue under sterile distilled water. A combination of tri-potassium citrate and citric acid incorporated in the medium significantly reduced phenolic browning, however this treatment had no significant effect on the number of somatic embryos formed suggesting that prevention of tissue browning may be feasible by reducing the contact with oxygen during excision of tissues.