Somatic Embryogenesis from Roots of Camellia japonica Plantlets Cultured in Vitro
Somatic embryos were induced on the roots of Camellia japonica L. plantlets regenerated from an in vitro clone of juvenile origin. The embryos appeared to differentiate from epidermic cells and to be connected with the root via a few parenchymatous cells. Somatic embryogenesis occurred on basal medium and with or without various combinations of zeatin, BA, and IBA. Secondary embryos were induced on cotyledons and/or hypocotyl regions of somatic embryos. Two morphological types of somatic embryos were developed, seed-like and bud-like types, and their formation was influenced by the presence of BA in the medium. Embryogenic capacity has been maintained for more than 24 months by subculturing secondary embryos at 7- to 8-week intervals. The best gibberellin/auxin combination for inducing the germination of isolated somatic embryos was GA at 5 mg·liter-1 G A3 and IAA at 1 mg·liter-1. P1antlets were successfully established in planting medium and have continued to grow in a greenhouse. Chemical names used: N-(phenylmethyl)-1H-purine-6-amine (BA); (1α, 2β, 4aα, 4bβ, 10β)-2,4a,7-trihydroxy-l-methyl-8-methylenegibb-3-ene-1,10-dicarboxylic acid l,4a-lactone (GA); 1 H -indole-3-acetic acid (IAA); 1 H- indole-3-butyric acid (IBA); 2-methyl-4-(1 H- purine-6-ylamino)-2-buten-l-ol (zeatin).