Study On Micropropagation Of The Introduced Stone Fruit Rootstock

The stone fruit trees of Rosaceae are one kind of the important non-timber species,mainly including peach,Plum,apricot,apricot and plum hybrid and cherry etc. At present,the grafting of fruit trees is the main breeding methods. The rootstock is the base of grafting, so the appropriate rootstock is important to improve the production,quality and resistance.The introducted rootstock is one of the excellent rootstocks, introduced from American in 2006. Compared with the domestic fruit varieties of main rootstocks,It has the prominent resistance to flow gumdisease and root cancer. The high efficient regeneration system establishment of stem section and mature embryos, not only solve the embryo dysplasia problem, but also propagate the breeding materials rapidly. Its establishment has the significance of the rapid propagation and the breeding.In the research, the introducted stone fruit rootstock was used as test materials to study the growth conditions during the process of every stage, including generation culture, proliferation culture, rooting culture and transplanting stage. The high efficient regeneration system of stem section and mature embryos had been preliminarily established. The results are as follows:1. During the annual sterilization expriment of explants, the results showed that the best period for obtaining test material was April to May, when the germination rate was higher and the germs were less. The sterilization method was 75% alcohol 9 s+0.1% HgCl2 8 min.2. Appropriate medium for the generation was MS+6-BA 2.0 mg.L^-1+ NAA 0.5 mg.L^-1after screening. The shoot clumps for proliferation were cultured on the medium MS+ BA 1.0 mg.L^-1+ NAA 0.5 mg.L^-1.The medium of 1/2MS+ IBA 0.8 mg.L^-1+ NAA 0.2 mg.L^-1was suitable for rooting. The plantlets transplanted into nutrition soil with peat soil, perlites, has the best effect.3. MS is the appropriate basic medium for embryo germination, through the research on the influences of various factors , such as medium type, hormone type and concentration , seed coat treatment to the mature embryo germination rate; the effective concentration inducing the embryo of BA is 4.0 mg.L^-1, and the concentration of NAA is 0.5 mg.L^-1; when the embryo soaked in the 20 mg.L^-1 GA for 24 hours, the germination rate of the mature embryo is up to 73.7%, and it is higher in the gemination rate and easier on the operation than the embryo cultured in the medium added GA, stripping part of the seed coat is better than other treatments.4. The method of improving agar content and reducing the concentrations of NH₄⁺,could control the vitrification phenomenon appeared in the process of proliferation to a certain extent. When the the agar content reached 6.0 g.L^-1,the vitrification phenomenon almost disappeared. Using 1/2 improved MS (1/2NH₄NO₃), vitrification rate reduced low to 3.2 percent.5. Suitable medium for proliferation with multiple shoot clumps of embryos were MS+ BA 1.0 mg.L^-1+ NAA 0.5 mg.L^-1after screening, and the multiples reaches 6 times. The rooting rate got 96.7% when the stems were cultured on 1/2MS+ IBA 0.8 mg.L^-1+ NAA 0.2 mg.L^-1. The plantlets were transplanted into nutrition soil with peat soil, perlite, acid soil, and the survival rate was 87.0%.