Study On Plant Regeneration System Of Section Aigeiros

Section Aigeiros is the most important section of Populus, and it playes significant economy role on forest production. In this paper, Populusxeuramericana'San Martino' and Populus deltoides 60/160xP.nigra 'chile' were used as experimental materials. Through observation and comparison, leaves and petioles sprouted from the cutting shoots cultured in water were selected as explants. Factors that affected plantlet regeneration of P.xeuramericana'San Martino' and Populus deltoides 60/160xP.nigra 'chile' were investigated systematically, such as different explant, medium, plant growth regulator and some supplements. The major results were following:1. The optimal sterilizing methods of leaves and petioles of P.xeuramericana'San Martino' and Populus deltoides 60/l60xP.nigra 'chile' were dipping into 70% Ethanol for 20 sec, and then treating with 0.1% HgCl2 plus Tween-20 (4 drops) for 9 min.2. Leaves and petioles were selected as the optimal explants for plant regeneration of P.xeuramericana'San Martino' . In MS medium appended with 0.5mg/L BA and 0.1 mg/L NAA, the ratio of callus inducement was 97.0% and the ratio of bud inducement was 91.1%. The addition of 150mg/L Vc to the medium could reduce the leaf browning efficiently, and decrease of browning rate was 25.0%.3. The optimal explant for plantlet regeneration of Populus deltoides 60/160xP. nigra 'chile' was the petiole. The callus was formed firstly but little, then the bud was induced generously. The best medium for bud inducement was MS+BA0.3mg/L +NAA0.1 mg/L, and the ratio of bud inducement was 82.5%.4. The proliferation coefficient was 6.3 after inoculating buds of P.xeuramericana''San Martino' into the medium- MS+BA0.3 mg/L +NAA0.05 mg/L; The optimal medium for subculture multiplication of Populus deltoides 60/160xP.nigra 'chile' was MS+BA0.2 mg/L +NAA0.05 mg/L and the proliferation coefficient was 7.2.5. The addition of suitable concentration of GA3 to the medium could raise the height and proliferation coefficient of buds. Adding 0.8mg/L and 0.4mg/L GA3 into the medium separately was apparently favorable to the subculture multiplication of P.xeuramericana1 San Martino' and Populus deltoides 60/160xP.nigra 'chile'.6. The best medium for rooting of P.xeuramericana'San Martino' was l/2MS+NAA0.05mg/L+IBA 为 0.2mg/L , and the ratio of rooting was 93.5%; The best medium for rooting of Populus deltoides 60/160xP.nigra 'chile' was l/2MS+NAA0.05mg/L, and the ratio of rooting was 96.5%.7. During transplanting the in vitro plantlets into the culture substrate mixed by the garden soil and gravel, the survival rate was high, and reached more then 90%.