Studies On Tissue Culture And Rapid Propagation Of The Cultivar MD110 Of Populus Maximowiczzi×P.deltoides

In this paper, the sterilizing procedures were studied by using different explants including buds, leaves and petioles from the two-year-old cutting shoots of MD100 of Populus moximowiczii×P. deltoides from Oji Paper Co., Ltd. The callus was induced from different explants, the buds and roots were differentiated from the callus.The sterilizing methods of the buds, leaves and petioles sprouted from the cutting shoots cultured in water in a greenhouse were investigated. The results showed that the optimal sterilizing method of buds was dipping into 70% alcohol for 10 sec, and then treating with 0.1% HgCl2 plus Tween-20 (4 drops) for 12 min. The contamination of the leaves and petioles in culture was largely improved when they were treated with 70% alcohol for 10 sec, and then treated with 0.1% HgCl2 plus Tween-20 (4 drops) for 10 min.The effect of medium and hormone on the callus induction from buds, leaves and petioles was studied. The results showed that the apical meristem was the. best for callus induction. The optimal induction medium was MS containing 1.15 mg/L 6-BA, and the rate of callus induction reached 100%.The callus was multiplicated rapidly on the MS medium with 6-BA. After cultured for 30 days, the diameter of callus was maximized to 1.1cm and the rate of callus proliferation was 100%. According to the economic principle and the efficiency of propagation, the most adaptable callus proliferation medium was MS medium supplemented with 1.15 mg/L 6-BA.The solid medium and liquid medium were used for the differentiation of the callus. The solid medium of 1/2(N) MS+0.3 mg/L6-BA+NAA0.1mg/L+2.5%sucrose was optimal, and the rate of shoot regeneration from the callus could reach 94%. While the rate of shoot regeneration from the callus cultured on the liquid medium of l/2( N) MS+0.3 mg/L 6-BA+NAA0.1mg/L +2.5%sucrose could reach 98%.At rooting culture, the effect of NAA was better than that of IBA. The optimal rooting medium was l/2( N) MS+0.05mg/L NAA+2.5%sucrose.During transplanting the in vitro plantlets into the vermiculite, the survival rate was the highest, and reached 90%. When the garden soil combined with vermiculite , the air permeability and humidity are poor, but the plantlets in this medium were stronger than those in the other media, and no other transplanting is needed before planted in nursery.