Studies On Tissue Culture And Virus-elimination Technique Of Dahlia

Dahlia pinnata, as a herb bulb flower, belongs to the Comprehensive familyDahlia genus. It has very high comprehensive utilization value in garden greening,food industry, biological energy and medical research applications. In recent years,the occurrence of virus disease, results in a decline in the serious of the quality ofdahlia, restricting the development of industry of dahlia. Dahlia infected dahliamosaic virus (DMV), cucumber mosaic virus (CMV-D2) and tobacco mosaic virus(TMV) for material, through stem tip method, stem tip in combination with physicaland chemical method was used to start detoxification test. The results were reflectedby enzyme linked immunosorbent (ELISA) for determination of detoxification effect.Rapid propagation technology of the virus-elimination seedlings was optimized. Itaimed to build a set of simple operation, fast efficient and stable effect ofdetoxification rapid propagation system, which would have a positive guidingsignificance for dahlia industry’s healthy development. The main results were asfollows:First, optimization research of tissue culture and rapid propagation1) Apical bud and axillary bud as the explant materials, soaked5minutes withweak alkaline solution, washed2hours with running water, then soak30seconds with75%alcohol solution, last treated with0.1%mercuric chloride for4~7min, andrinsed clean with sterile water. Then we can obtain asepsis explant materials. Theirsurvival rate could be up to80%on average. Appropriate dahlia original culturemedium was MS+6-BA4mg/L+NAA0.2mg/L+sucrose40g/L+agar6000mg/L.Joining2000mg/L activated carbon in the medium, could reduce the browning rate.2) Suitable successive transfer culture medium for seedlins was: MS+6-BA1.5mg/L+NAA0.2mg/L+sucrose40g/L+agar6000mg/L. Tube seedlings growed upto5~8cm30days later.3) Suitable rooting medium for dahlia was:1/2MS+NAA0.1mg/L. Rootingrate could be up to78.79%, and the root was strong.Second, research of detoxification technology1) Stem tip culture of dahlia: due to operating difficulties, detoxification rate forthree kinds of virus was only about10%.2) Dahlia stem tip in combination with heat treatment: to reduce the harm ofdahlia tube seedlings by high temperature, the variable temperature treatment wasused. Gradually raised the temperature to36℃under light; to33℃under dark.Heat treatment was began. For the limit time, heat treatment time was up to25days,tube seedlings’ survival rate was40%. The DMV, CMV-D2’s removal rates were74.7%and66.9%respectively, but it could not effectively remove TMV, all three kinds of virus’ removal rate was10.6%.3) Dahlia stem tip in combination with chemical treatment: when theconcentration of ribavirin reached25mg/L, three kinds of virus removal rate was thehighest,83.1%,80.5%and77.1%respectively. DMV, compared with other two kindsof virus was more likely to remove. Three kinds of virus all removal ratio was24.3%.But25mg/L ribavirin concentration treatment on tube seedlings caused growthinhibition slightly. Transgenerational after3~5times, inhibition could reduce or fallto zero.4) Comparison of stem tip in combination with heat treatment and stem tip incombination with chemical on tube seedlings detoxification effect: through the studywe found that, heat treatment and chemical treatment both could remove DMV, CMV-D2and TMV. No significant effect of heat treatment on TMV removal, the highestdetoxification rate was only32.4%; Stem tip in combination with chemical treatment,for comparison, were more effective removal of three kinds of virus. On the one hand,when the concentration of ribavirin was25mg/L, three kinds of virus removal ratereached80%, virus-elimination rate was high, on the other hand, just adding ribavirinin culture medium, without expensive precision instrument, the operation was simple.As a result, treating with25mg/L ribavirin concentration for1cm stem tip for40days, then cutting1mm meristem-tip culture, was the best detoxification methodsuitable for dahlia.