Research About Development Of Bulblets And Virus-free In Vitro Of Chongming Daffodil (Narcissus Tazetta Var. Chinensis)

Chongming Daffodil (Narcissus tazetta var. chinensis) is one of the most famous flowers in Shanghai which has a long cultivatural history. Now, there are many disadvantages, such as low rate of propagation, hurt of virus, reduce of products, etc., which have hindered the development of industrialization of Chongming Daffodil.In this study, several factors affected the induction and multiplication of bulblets in vitro were discussed to obtain higher frequency, and a higher-efficient induction and multiplication system were established; the bublets in vitro treated with DHT+thermotherapy or DHT+virazole were used to eliminate virus diseases.Main results were as follows:1. Pretreating the bulbs at 4℃for 4 weeks before inoculation could improve the induction rate remarkably when leaf lamina with basal plate was used as explant.2. The pollution rate decreased to 8.3% through marinating cutting bulbs in 1000mg/L Cefradine liquor for 3 hours.3. Rachis was the most fitting explant to induce the bulblets in vitro directly. The MS medium with 10mg/LBA, 5mg/LNAA and 30g/L sucrose was founded to be optimum for induction bulblets from rachis, the effective induction rate reached 171.3%. The medium containing 1mg/LBA, 1mg/L NAA and30g/L sucrose was fit for bulblets developed from leaf lamina with based plate.4. The inner leaf lamina pretreated under low temperature (4℃) for 3 weeks was the feasible explant to induce callus, the rate of induction was 48.4%, and the differentiation rate was 23.3% when inoculated on the MS medium with 1mg/L BA, 0.1mg/L 2,4-D and 30g/L sucrose. 51.9% callus can be induced from ovary on MS medium containing 10mg/L BA, 3mg/L NAA, and 22.2% was successfully differentiated to bulblets.5. The medium with 5mg/LBA, 1mg/LNAA , 40g/L sucrose and without AC was fit for propagation. The higher sucrose concentration was good for bulblets proliferation and growth, but 40g/L was suitable. And AC reduced the propagation rate observably.6. 1/2MS medium with 0.5mg/LNAA and 1g/LAC was the most efficient medium for rooting, 90.4% bulblets had grown roots after 20 days.7. DHT with thermotherapy treatment could decrease the content of viruses. The content of NMAV in bulblets in vitro treated with 30mg/L DHT +30mg/L virazole was reduced to a very low level, and the treatment didn't have impact on bulblet's survival. NDV-free and NCLV-free plants were obtained by the treatment of combination of 10mg/L DHT and 10mg/L virazole, the viruses could not be detected by RT-PCR.