Preliminary Study On The System Of Regeneration And Doubling In Vitro Of Chinese Jujube (Ziziphus Jujuba Mill.)

Chinese jujube (Ziziphus jujuba Mill.), belongs to Ziziphus genus, Rhamnaceae family. It originatied in China and becomes an important ecological and economic plant in our country. The jujube fruit is one of the favourite fruit due to the value of diet therapy and health care. In this thesis, the seeds of’Dongzao’was used as the material, the morphological indexes was measured, and the rate of kernel was counted. Then the optimal condition for seed germination was studied and the appropriate medium for hypocotyl callus induction was selected. The new born shoots with buds from the trees of ’Chahuzao’were as the explants to establish the in vitro tissue culture system by explants sterilization, initiation culture, multiplication culture, rooting culture, acclimatization and transplant. And the leaves of the tissue culture seedlings were used to establish high efficiency regeneration system. Then in vitro chromosome doubling by treating leaf explants with colchicine were investigated. The study laid a foundation for genetic transformation, in vitro polyploidy induction, germplasm preservation, etc. The main results are as follows:1. The seeds were obtained from the’Dongzao’mother tree by natural hybridization.The transverse diameter and vertical diameter were measured, the thousand kernel weight (TKW) was weighted, as well as the rate of kernel was counted. And the optimal condition for seed germination was studied.(1) The rate of kernel was (64.17±3.82)%, so’Dongzao’was one of the high rate varieties of Ziziphus jujuba Mill.(2) The seed germination could reach100%on medium with GA30.4g/L for24h pretreatment.2. The new born shoots with buds from the trees of’Chahuzao’were as the explants to establish the in vitro tissue culture system, which laid a foundation of high efficiency regeneration system.(1) The suitable initiation medium was MS+6-BA2.0mg/L+IBA0.2mg/L+NAA0.2mg/L, the length of new shoots was (24.72±0.26)mm and the survival rate was85.71%after cultivation of20d; the initiation medium with lg/L polyvinyl pyrrolidone aggravated the explants browning, instead of avoiding it.(2) The suitable subculture medium was MS+6-BA2mg/L+IBA0.4mg/L, the length of new shoots was (35.64±0.60)mm after cultivation of30d; the suitable meristematic medium was MS+6-BA4.0mg/L+NAA0.2mg/L, the enhancement factor was3.87±0.34after cultivation of30d.(3) The in vitro shoots root well in the modified1/2MS+NAA0.2mg/L+IBA0.4mg/L, rooting percentage can reach to100%, seedling transplanting survival rate was95.56%.3. After the regeneration system of’Dongzao’hypocotyl and’Chahuzao’leaf was established, regeneration plants were obtained, which provided materials to autopolyploid induction with the treatment of colchicine.(1) The highest hypocotyl callus induction rate ((60.00±3.02)%) was obtained on1/2MS basal medium supplemented with1.0mg/L TDZ and30g/L sucrose after14days incubation in darkness.(2) The buds regeneration frequency can achieved100%on the media of MS+TDZ0.5mg/L+6-BA1.0mg/L after21d dark culture so and21light culture in order.4. The’Chahuzao’in vitro doubling system of was set up initially. The suitable colchicine treatment is50-70mg/L for2-3d.