Studies Of Stem Tissue Culture For Dioscorea Nipponica

Dioscorea nipponica belongs to dioscoreaceae,is one kind of climbing perennial herb.With its higher medicinal value of its rhizome,wild resources were decreased due to human constantly digging dramatically.In order to meet the market demand of medicinal material and reduce the destruction of wild resources,we collect stem of Dioscorea nipponica Makino as explants,carried out its initial culturing,reproducing,rooting,and plantlets transplanting,finally built the regeneration system of this species.The results of this study may provide technical support for plant breeding of Dioscorea nipponica.The main results are as follows:(1)Explants disinfection:The best combination to sterilize the explants for stems was 75%aclcohol for 30 seconds,and 0.1%HgC12 for 5minutes,the rate of survival was 83.33%.(2)Primary culture:Axillary buds induction with the stems as explants.The most suitable medium is MS+NAA0.2mg/L+6-BA 2mg/L,and the germination rate was 86.67%.(3)Subculture:The most suitable medium was MS+NAA 0.2mg/L+6-BA 3mg/L.,the multiplication rate was about 4.58.The best period of subculture cycle was 30 days,the best subculture times was 3 times.(4)Rooting culture:Different medium have great influences to morphological characteristics of seedlings.1/2MS+NAA0.1mg/L as the best rooting medium,the rooting rate was 73.34%.The best concentration of sucrose was 20 g/L.(5)Refine and transplanting:Transplanted into pot with matrix were rotten quality soil,vermiculite and river sand by 1 to 1 to 1,The mixture of was used as the substrate of transplantation.After 1 week,new leaves come out and the seedlings grow well,survival rate is up to 63.20%.