Research On Tissue Culture Of Populus Deltides 'Harvord' And Populus Deltides 'Lux'

With the good characteristics of fast-growing in early stage and high resistances, popular of Section Aigeiros of was widely planted in the world. It was introduced to China in 1970s'. Some varieties such as Populus deltides 'Harvord' and Populus deltides 'Lux' and Populus×euramericana 'San Martino' were important breeding parents. After lots of generations of cloning propagation, these varieties showed physiological aging and degradation. In this dissertation, regeneration technology via tissue culture of P. deltides 'Harvord' and P. deltides 'Lux' was systematically studied. Major results were as follows:(1) The best explants of these two varieties were both young leaves and petioles cultured in water in house, with low pollution and brown rates. Two-step facial sterilization was applied for explants. The very young explants were immersed into 70% ethanol for 30 sec, and were then treated with 0.1% HgCl₂ for 4 min. The relatively older explants were immersed into 70% ethanol for 30 sec, and were then treated with 0.1% HgCl₂ for 5 min.(2) P. deltides 'Harvord' regenerated via indirect organogenesis, i. e., callus was first induced from explants, then shoots were induced from the callus and finally roots were induced form shoots. The optimum callus induction medium is MS＋sucrose3%＋6-BA 1.0mg/L＋2,4-D 1.0mg/L and the induction percentage is 92.1%. The optimum buds induction medium is MS＋sucrose 3%＋6-BA 0.8mg/L＋NAA 0.3mg/L and the induction percentage is 88.4%. The optimum subculture and multiplication medium is MS＋sucrose 3%＋6-BA 0.5mg/L＋NAA 0.2mg/L＋GA₃ 0.2mg/L and the multiplication coefficient is 5.4. The optimum mature shoots medium is MS＋sucrose 3%＋6-BA 0.2mg/L＋1BA 0.5mg/L and the average height of shoots is 1.2cm. The optimum rooting medium is 1/2 MS＋sucrose 2%＋6-NAA 0.05mg/L and the rooting percentage is 83.3%.(3) P. deltides 'Lux' regenerated via both direct and indirect organogenesis. The optimum callus induction medium is MS＋sucrose 3%＋6-BA 0.5mg/L＋2,4-D 2.0mg/L and the induction percentage is 100%. The optimum medium for buds induction from callus is MS＋sucrose 3%＋6-BA 0.8mg/L＋NAA 0.3mg/L and the induction percentage is 73.4%. The optimum direct shooting medium is 1/2MS＋sucrose 4%＋6-BA 1.0 mg/L＋NAA 0.1mg/L and the shooting percentage is 81.0%. The optimum subculture multiplication medium is MS＋sucrose 3%＋6-BA 0.5mg/L＋NAA 0.2mg/L＋GA₃ 0.2mg/L and the multiplication coefficient is 5.0. The optimum mature shoots medium is MS without any hormone and the average height of shoots is 1.0cm. The optimum rooting medium is 1/2MS+sucrose 2%+6-NAA 0.05mg/L+IBA 0.1mg/L and rooting percentage is 79.1%.