Factors afecting somatic embryogenesis induction and conversion in "paradise tree" (Melia azedarach)

VILA,S; REY,H; MROGINSKI,L

JOURNAL OF PLANT GROWTH REGULATION

Año: 2006

0721-7595

Factors affecting somatic embryogenesis induction and conversion in paradise tree (Melia azedarach) were evaluated. Somatic embryogenesis was influenced by plant growth regulators, explant stage, carbohydrate source and concentration, gelling agents, light and induction times. MS medium with 1 mg/L TDZ resulted to be the best for the induction of embryogenic tissue. Zygotic embryos that were 1-1.5 mm long (torpedo and early cotyledonar stage) had a greater embryogenic response than smaller or larger embryos, and better conversion of somatic embryos obtained into plants. In general, embryos that formed in medium containing 1% or 5% of carbohydrate source were hyperhydrics or fused respectively, while those that formed in medium with carbohydrate concentration of 3% had better morphology. Raffinose at 3% yielded a satisfactory somatic embryo induction with good morphology and the best values of conversion into plants. Induction and conversion of somatic embryos was superior on medium solidified with Agar A-1296. The explants maintained under 160 µmol m-2 s-1 or 1 week in darkness and later 160 µmol m-2 s-1 produced a significantly higher embriogenic index. Only 4 days of treatment on induction medium, with either raffinose or sucrose at 3% as carbohydrate source, were required to induce somatic embryogenesis, but longer exposure, until 18 days, increased the yield and improved the morphology of somatic embryos.