The Research On Asexual Propagation Of Zelkova Schneideriana

Zelkova schneideriana belongs to Ulmaceae, it's endemic to China. Because its germination rate was low, natural regeneration difficult, and suffered frequent human deforestation, the number has been relatively scarce, it is listed as second-class key protected plants.Propagation by the seed of Zelkova schneideriana is difficult to maintain their good character and have great individual differences.between offsprings. Thus, cloning technology will be played a leading role in breeding of good varieties and mass production. In order to discuss the impact of different cloning technology on the propagation and make sure of appropriate technology.Zelkova schneideriana cloning techniques, including grafting propagation, cutting propagation and tissue culture techniques, were studied. The results are as follows:1. Cutting Propagation of Zelkova schneideriana(1) Substrate on cuttings Rooting rate in vermiculite was the highest (75.00%), followed by perlite:peat 3:1 and perlite, rooting rate of 56.25% and 59.37%, but the roots in vermiculite are single roots, and in perlite and perlite:peat 3:1,it has more developed root system root. Therefore, the suitable substrate for cuttings of Zelkova schneideriana is perlite:peat moss or perlite 3:1.(2) Exogenous hormones on cuttings3a-branches of Zelkova schneideriana were used to do cuttings, perlite:peat 3:1 as a substrate, four kinds of hormone as hormones on the cutting experiments,, RootingPower, Horm (1,2,3), NAA and IBA-K+. Taken rooting rate, root number and root length into account, Horml is more appropriate for rooting of cuttings; NAA can promote the number of roots; IBA-K+ can play a prominent role on growth of root length.The test of NAA and IBA-K+ two mixed rooting hormone show that, NAA3000+IBA-K+3000 is more appropriate for the cuttings of. Zelkova schneideriana.(3) Test of Mother trees of different age groups on the rooting of Zelkova schneideriana Select year, three years, ten years, fifty years of Zelkova schneideriana to do cutting test, the specifications of the cuttings diameter of 0.6cm～1.0cm, and to perlite: peat 3:1 as a substrate, Horml for the hormone, results showed that the rooting rate of branches of Zelkova schneideriana is the highest,87.00%, significantly higher than three years old branches rooting rate 17.60%, while the ten years and fifty years of health mother trees branches do not root.(4) Cuttings test of different species of Zelkova schneideriana Select the branches of one year of the three varieties of mother Zelkova schneideriana,YS1, YS2 and YS3, as the cuttings, use Horm1 as hormones, perlite:peat 3:1 as a substrate, the rooting rate of YS2 is 70.00%, the rooting rate of YS1 is 46.40% and the rooting rate of YS3 is 36.30%. YS2 (green) has the highest rate of rooting and the regenerated plants grew well.(5) Site of cuttings on the rooting rate of Zelkova schneideriana Used three years of cutting old branches, selected peat:perlite 3:1 as substrate, Horml as hormones, the forpart of Zelkova schneideriana of the rooting rate was 24.10%, the middle of the rooting rate of 7.60%, lower rooting rate of 2.80%.Thus,The forepart of Zelkova schneideriana branches is higher than the middle and lower segments, the forepart of Zelkova schneideriana branches is more appropriate for the cutting.(6) Hardwood cuttings in winter experiment:Hardwood cuttings trial found cutting of diameter greater than 1.2cm, with perlite as a substrate, Horm1 as hormones, the survival rate of up to more than 80%, the average number of taproot is 3, the average length of the root is 3.8cm.2. Zelkova schneideriana grafting techniqueSelect la Celtis biondii Pamp. as tree stock and 3a robust Zelkova schneideriana as scion budwood.(1) Grafting methods and seasonStem grafting and budding in spring, the average survival rates were 28%,30%; average survival rates of stem grafting and budding in summer are 84%, stem grafting and budding has no significant effect on the survival rate; grafting survival rate in summer is significantly higher than in spring, so summer is a good choice for grafting time.(2) Grafting materialStem grafting in spring:Taken from the mother tree upper scion, lower scion,the grafting average survival rates were 16% and 42%; budding in spring:the average survival rates of the upper bud,the lower bud grafting were 4% and 56%. Therefore, the spring grafting material should be selected the lower part of mother tree,which is more appropriate; stem grafting in summer, the survival rates of the upper scion,the lower scion were 92% and 76%; the top bud grafting bud and the lower bud survival rate were 100% and 70%. Therefore, the choice of materials over the department in summer is appropriate. Summer survival graftingl rate was significantly higher than in the spring.3. Zelkova schneideriana propagation techniques of tissue cultureFactory technology of Zelkova schneideriana is on a preliminary study. Order in the near future a large number of excellent seedlings Zelkova schneideriana, Germination of seeds and seedlings of the stem terminal bud explants were cultured with WPM medium, after two months, and not directly induced by a bud, but the formation of a callus. Factory preliminary study is not satisfactory. In the study, found TDZ1.0 for Zelkova schneideriana has a high ability to induce callus, but callus tissue culture in the subculture process, TDZ easily calli black.In short, the comparison method of asexual reproduction found in Zelkova schneideriana, although the rooting rate of cuttings is not high, but is still a better way for Vegetative Propagation of Zelkova schneideriana. At present, the factory is still not mature, and can not directly induce a large bud. Zelkova schneideriana grafting technology in addressing a large number of breeding, there are still some limitations, but to do modeling for Zelkova schneideriana bonsai is a better way.