Tissue Culture Of Populus Davidiana × P.tremuloides And The Effect Of Several Physiological Characters To The Seedling's Rooting

In this paper elite explants of Populus davidiana and P.tremuloides were used as researchmaterials. To establish and consummate the tissue culture propagate system, search for thecondition and rules of crossbreed Populus test tube breedings constitution. Contemporary,study on several physiological variety deeply during rooting. The conclusions were as follows.1. Tissue culture systerm: The optimal sterilizing method of buds was dipping into 70% to75% alchohol for ten to twenty seconds, and then treating with 0.1% Hgcl₂ for about 3rain; theoptimal material for propogation by multiplication is of axillary buds; The optimum culturemedium of differentiation was NT+6-BA1.0mg/L+KT0.3mg/L+2%sucrose, the differentiationrate was 87%, a single explant can differentiated 4.32 buds at best. The optimum proliferationculture medium was WM+6-BA0.5mg/L+NAA0.01mg/L+2%sucrose. High temperature,airtight plastic membrane and weak light can promote the vitrification, of all, the airtightplastic membrane is the most important factors. WM+ IBA1.5mg/L+IAA0.01mg/L+2%surosewas the optimum culture medium of rooting. The rooting rate was up to 88.9%, a singleseeding has 14 roots at the most. Study on the influence of factors to rooting emphatically,There were prominent difference in the seedling age to influence on rooting rate and rootingnumbers, the rooting ability which in the 30dto 35d seedling age is the most strongly.Therewere no significant difference in rooting rate, rooting days and even rooting numbers of stemshave stem apex or not. Determine by genetics, the rooting ability of different clones is ZM3＞ZMI＞ZM6＞ZM7＞ZM9＞ZM2＞ZM4＞ZM10＞ZM8＞ZM11＞ZM5; To choose thestrong, haven't polluted seedling to transplant, which have no callus in the stems, the suitablemedium of test-tube transplants was the mixture of perlite and humus, which is mixedaccording to the scale of 1:1, the moisture in the air should be kept above 70% by leaf sprayingduring the first 5 days after transplanting .In the experiment, the survival rate of transplantsreached above 90% with the best treatment.2. Result of rooting mechanism research: Based on the different rooting ability of varycrossbreed clones, track on the content of four kinds of endogenesis hormonal and thesolubility Protein, and the activity of the POD and the PPO, during the root inducing days. Tocontrast the result to the status of rooting ,we draw the conclusion that there are positivecorrelation between the initialized IAA, ZR the rooting rate a, negative correlation betweenABA, GA and rooting rate, IAA and ZR are the most important facters to accelerate rooting andABA is the most important facter to restrain rooting, during the root primordium differentiation,the content of solubility Protein are all hoisting wether it's rooting ability is strong or not.There is grate variety in easily rooting clones and little in hardly rooting clones. Some kind of solubility Protein would condence the quantity programmly after the root grow out, thisilluminate the amount of protein are related to the toots' growth; there is a positive correlationbetween the activity of PPO at the beginning of root primordium shaping and rooting ability,and there are no rules in different clones during rooting days; there are vales during the rootprimordium shapping, and the lower the activity, the higher the rooting rate, which illustratethe reducing on activity of POD promoted the rooting.