| A large area of the saline-alkali land are mainly sited the northwest, north and northeast parts of China and the east coast region. With development of industry, growth of population and decreasing of arable land, selecting and breading plant material for salt resistance and rationally using saline-alkali land are very significant.Poplar is the major species in the northwest, north and northeast parts of China and the number of the species in the area is big. Kiwifruit is a new kind of fruit tree with high economic value. Improving salt resistance of the two species and enlarging their planting region are good ways for using saline-alkali land rationally and have an important meaning in practice.In this experiment, mtlD/gutD divalent genes were transformed into poplar and kiwifruit trees. Leaf-disc method and microprojectile bombardment were adopted for gene transformation. Binary plant expression vecter is pBIMG which contains mtlD/gutD divalent genes, double strength 35S promoter, translation enhancer from TMV " & "fragment and NPT- II kanamycin-resistant marker gene. The strain of Agrobacterium tumefaciens is LBA4404. Populus deltoilds X P. cathayana and Qingmei kiwifruit variety, were used in the experiment as plant materials. The main research works are as follows.1 ? Leaf explant regeneration systems of the poplar and kiwifruit were established by orthogonal design, the experiment results indicated that the optimum medium compositions of poplar were MS+6-BA 0.5 mg/L+NAA O.Olmg/L for inducing shoot from leaf explant, and 1/2 MS+NAA O.Olmg/L for inducing root from shoot. The optimum medium compositions of kiwifruit were MS+6-BA6mg/L+NAA 0.01 mg/L for inducing shoot, and 1/2MS+NAA O.Olmg/1+IBA 0.5mg/L +GA Img/L for inducing roots.2> kanamycin sensitive experiment showed that the critical kanamycin sensitive concentrations for inducing shoots and roots of the poplar were 50 mg/L and 60mg/L.The critical kanamycin sensitive concentrations for inducing shoots and roots of the Qingmei kiwifruit were 50 mg/L and 40 mg/L.3 > On the basis of experiments above, a study on transforming mtlD/gutD divalent salt resistance genes into poplar by leaf disc method was carried out. Through kanamycin continuously screening in the shoots and roots induction stage, 38 kanamycin-resistant rooted poplar shoots were obtained. PCR analysis showed that 28 of these kanamycin-resistant rooted plants were positive. 7of these 28 PCR positive plants weretaken out for Southern blotting and Western blotting , the result indicated that 4 of the 7 plantlets were positive for both. It means that mtlD/gutD divalent genes were successfully integrated into the genome of these 4 plantlets, and the proteins expressed by mtlD/gutD divalent genes were synthesized. Combining leaf disc method and microprojectile bombardment, a study on transforming mtlD/gutD divalent salt tolerance genes into kiwifruit was conducted. Through successive selection in the period of shoot and root induction under high lever kanamycin pressure, 20 kanamycin-resistant rooted plants was obtained, out of which, 6 was positive through PCR analysis.4. Results from salt tolerance tests indicated that the NaCl tolerance concentration of 4 transgenic poplar plantlets can reach to 0.4~0.6% while the highest NaCl tolerance concentration for normal poplar (control) was 0.2%. The highest NaCl tolerance concentration for normal kiwifruit (control) was 0.1%. In 6 PCR positive kiwifruit plantlets, the salt resistant ability of 2 plantlets was the same as that of control, but the sodium chloride tolerance concentrations of another 4 kiwifruit plantlets can reach to 0.2%-0.4%, which was higher than that of control plantlets.On the basis of establishment of leaf explant regeneration system for poplar and kiwifruit species and the kanamycin tolerance concentration , studies on transforming mtlD/gutD divalent salt tolerance genes into poplar and kiwifruit species by leaf-dish method ,and combination of leaf disc and microprojectile bombardment method were developed. Re...
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