A Study On Tissue Culture And Rapid Propagation Of Three Varieties Of Actinidia Arguta Planch

Actinidia arguta（kiwifruit）is a species of genus Actinidia of Actinidiaceae family.Because it is highly resistant to low temperature and its fruit is rich in nutrients and has a unique flavor,this species has been developed a new kind of kiwifruit that people like more and more.However,A.arguta can not be propagated efficiently via traditional ways,establishing its in vitro propagation system will accelerate large-scale application of its elite varieties.‘Fenglv’,‘Kuilv’and‘No.2 Longcheng’are high-quality varieties of A.arguta.In this study,suitable sterilization time was examined using newly-formed shoots of the three varieties as explants,and the effects of plant hormones and basal medium on shoot proliferation and rooting were extensively investigated,and the regenerated plantlets of these varieties were successfully transplanted in pots.Following main results were obtained.1.In the experiments of explants surface sterilization,sodium hypochlorite solution（1%active chlorine）containing 2 drops of Tween 20 per 100 ml was used as disinfectant and three disinfection times（10,13 and 15 minutes）were selected.The results showed that the 10 min treatment had high contamination rates（35-40%）,but low death rates of explants（10-15%）and low bud growth rates（10-20%）;the 15 min treatment had low contamination rates（0-25%）,but high death rates of explants（30-40%）and low bud growth rates（about 20%）;the 13 min treatment had a contamination rate of 30%and an explant death rate of 20%,but a higher bud growth rate（30-35%）.It was concluded that the suitable sterilization time was 13min for the newly-formed shoots of the three varieties.2.Different concentrations of 6-benzylaminopurine（BA）,kinetin（KT）,zeatin（ZT）and thidiazuron（TDZ）were added alone or together with gibberellin acid 3（GA₃）in MS to test their effects on shoot proliferation of the three varieties.The results indicated that BA was the best cytokinin for the shoot proliferation,and GA₃ could significantly promote shoot elongation and lateral bud growth,leading to high proliferation efficiencies.The optimal hormone combination was 0.5 mg/L BA and 0.5 mg/L GA₃ for‘Fenglv’shoot proliferation,which yielded an average proliferation rate of 5.5 times within one month of culture.The optimal hormone combination was 0.5 mg/L BA and 0.2-0.5 mg/L GA₃ for‘Kuilv’shoot proliferation,which yielded an average proliferation rate of 4 times within one month of culture,and the optimal hormone combination was 1 mg/L BA and 0.2 mg/L GA₃ for‘No.2Longcheng’shoot proliferation,which yielded an average proliferation rate of 3.8 times within one month of culture.3.The effects of different basal medium（MS、B5、CF and WPM）,in which 0.5 mg/L BA and 0.5 mg/L GA₃ were added,on shoot proliferation of the three varieties were tested.The results showed that MS was the best medium for shoot proliferation and growth of the all varieties.4.The shoots propagated on proliferation medium of the three varieties were planted on1/2MS supplemented with 0-0.8 mg/L indole-3-acetic acid（IAA）,indole-3-butyric acid（IBA）or 1-Naphthylacetic acid（NAA）to test the effects of different auxins on rooting of the shoots.The results demonstrated that both NAA and IBA could efficiently induce shoots of the three varieties to form roots,but IBA was much better than NAA because NAA easily stimulated the shoots to form large-size callus at the base as well as roots.In the medium which contained 0.2 to 0.5 mg/L IBA,almost all shoots produced roots within one month and averagely more than 4 roots per plant.5.The regenerated plants of the three varieties grew normally and healthily after they were transplanted in pots in greenhouse.After one month of transplantation,the survival rates were 90.9%、91.7%and 82.7%for‘Fenglv’,‘Kuilv’and‘No.2 Longcheng’,respectively.