Study On Somatic Embryogenesis And Callus Of Acacia Podalyriifolia

Acacia podalyriifolia is a silver leaved large shrub to small tree and native to Queesland Australia. It is introduced by Guangxi Academy of Forestry in 1981. Flowers occur in ball shaped clustersin the axils with a golden yellow color. Full bloom is extremely beautiful and suitable to be a landscape tree.The main content of this experiment were as follow:A study of four parameter (development stage of immature zygotic embryos, the type of explant, basic medium, plant growth regulators combination and light intensity ) was carried out to deteimine the best combinnation for the somatic embryogenesis induction of Acacia podalyriifolia. At the same time, the emperiments on callus induction, subculture and shoot differentition were carrid out. This is the first study on somatic embryogenesis in Acacia podalyriifolia.The main results were described as follows:Somatic embryogenesis in A. podalyriifolia was induced from immature zygotic embryos. The immature zygotic embryos of 48 to 52 days were more efficient than other collection time of immature zygotic embryos. The immature zygotic embryos of 48 days were the most efficient explants for somatic embryogenesis inducion. The intace immature embrys were most efficient induction(23.1%).All of the explants of ovules did not induce somatic embryogenesis.The induction (3.4%)in dark is higher than light(2.0%).The optimum hormone combinations were 1.0mg/L 2,4-D, 0.5 mg/L BA and 1000mg/L CH for somatic embryogenesis. Somatic embryogenesis was significantly influenced by concentrate of BA and casein hydrolysate.The soamtic embryos of A. podalyriifolia mature on 1/2MS medium containing 5.Omg/L GA3, 30g/L sucrose and 6g/L agar, but did not germinate.About different explant, the experimental results showed that the effects of callus induction was as the order:hypocotyl > immature zygotic embryo> leave > stem.The experimental results showed that the most suitable media for callus induction was MS containing 2.0mg/L 2,4-D, 0.2mg/L BA.The average induction rate was 85.4%. The testure of callus from different explants was different. The callus from hypocotyl and immature zygotic embryo belong toâ… friable vigorous callus; the callus from leaves and stems belong toâ…¡massiness callus.The dark conditon is more suitable for callus induction.Subculture of callus in A. podalyriifolia: The type of friable white or light-yelllow callus could be maintained for 3 times subculture on media with 0.5mg/L 2,4-D and 2.0mg/L BA.The conditon with light was more suitable for callus subculture than dark.Differentiation of adventitious buds from callus in A. podalyriifolia: The adventitious buds differentiated from callus after subcultured 2 times on meida MS with 0.01mg/L TDZ and 0.1mg NAA. The induction was 32%.