Somatic embryos of Juglans regia transformed with Agrobacterium rhizogenes Rol B gene and non-transgenic lines were proliferated on basal DKW medium. They were then transferred to media containing different concentrations of ABA, IBA and BA to increase the rate of proliferation and maturation. Transgenic embryos required 50 μM ABA and 40 μM IBA whereas non-transgenic embryos required 40μM ABA and 10 μM IBA. Neither kind of embryos required BA. Roots were. induced by drying embryos at 75% for 2-3 weeks until they lost about 30% fresh weight and then transferring them to basal DKW medium for an additional 2 weeks in the dark. Over 50% of the somatic embryos grown on medium containing both ABA and IBA developed well defined root systems compared to less than 15% of embryos grown on basal medium. A combination of 27 μM GA, and 9 μM BA was needed for development of shoot systems and germination of both transgenic and non-transgenic rooted embryos. Anatomical studies followed to characterize the extent of development at each stage.
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