Abstract:

Somatic embryogenesis and plant regeneration of Fraxinus rhynchophylla were obtained by using single cotyledons of zygotic embryos as explants. Cotyledons of immature zygotic embryos, cultured on half strength MS medium supplemented with 400 mg·L^-1 hydrolyzed casein, 70 g·L^-1 sugar, 6 g·L^-1 agar, 0.25 mg·L^-1 6-BA and 1.5 mg·L^-1 NAA, were able to be successfully induced somatic embryos. The somatic embryo (SE) induction rate could reach 34.7% and about 2-9 SEs were produced per each explant. However, cotyledons from mature zygotic embryos, culture on a similar medium with modification of adding extra 0.5 mg·L^-1 NAA, and the SE induction rate could reach 10.0%. Somatic embryos after in vitro maturation on a MS1/2 medium could normally germinate, and the germination percentage rate reached to 87.6%. The germinated somatic plantlets grew well on MS1/2 medium containing 0.01 mg·L^-1 NAA and had the similar morphological characteristics of zygotic seedlings. Acclimated somatic plantlets grew normally after transplanted in a medium with 50% peat moss, 40% vermiculite and 10% polite, with 75.0% survival rate.

Key words: Fraxinus rhynchophylla, tissue culture, somatic embryogenesis, plant regeneration