The Research Of Virus-free Treatment And Health Assessment Technique On Chrysanthemum Varieties "Japanese Red"

Chrysanthemum virus B (CVB) is one of the main harmful viruses of chrysanthemum, it causes the yield declining. In this study, The chemical treatment, heat treatment and cryopreservation were applied to eliminate chrysanthemum virus B (CVB) from chrysanthemum, and the advantages and disadvantages of these virus-free technology and healthy detection methods were compared in this research. The infected plants with CVB were tested by DAS-ELISA and PCR, the tissue culture system of the infected plants was set up firstly. The main results were as follows:In according to the documents, we select the appropriate environmental conditions and put the MS medium as the basic medium to create a rapid propagation system of chrysanthemum. The results showed that temperature and season could affect the explant contamination rate and the best effect was with 0.1%, mercuric chloride solution on the "Japanese Red" stem for 6 min. The best initial medium was MS+BA1 mg/L+NAA0.5mg/L; the best subculture medium was MS+BA1 mg/L+NAAO.lmg/L and the best rooting medium was 1/2MS+NAA0.1mg/L.Shoot tip culture as a reference experiment for the elimination of CVB,which were tested by DAS-ELISA and PCR, none virus-free were acquired. That meant that the CVB virus could not be removed by shoot tip culture directly.The two chemical agents, the 2-thiouracil and the ribavirin were used in the treatment experiments. The 2-thiouracil and the ribavirin were applied according to the following four concentration gradients.. The results showed that 2-thiouracil was rather harmful of chrysanthemum, and the virus-free effect was not obvious. The ribavirin was less harm for chrysanthemum, its concentration of 4mg/L was the moret cost-effective treatment for eliminating CVB, with a virus-free rate of 88.2%. Three temperature gradients and five time gradients were designed in the heat treatment 30 days later, Meristems(0.5-1.0mm diameter) of plantlet were cut and cultured on shoot tip medium.The results suggested that the heat treatment of 30 days of shoot tips could be the simple and cost-effective treatment for eliminating CVB, with a high survival rates,were 81.2% and 80%.The vitrification and encapsulation-vitrification based cryopreservation procedure was tried and the plantlets were recultured on shoot tip medium after cryopreservation. Some shoot tips survived after the pre-treatment with the vitrification of PVS2 with 40 min,that meant the preliminary progress had been made for the application of cryotherapy also. But never shoot tips survived after the pre-treatment with the encapsulation-vitrification.. The results suggested that the more research should be made although it could be the most cost-effective treatment for eliminating CVB.Above all, the heat treatment of 30 day and 4mg/L of the ribavirin were the cost-effective treatment for eliminating CVB. Although the effect of cryopreservation could be expected, the problem of the shoot tips survival should be solved firstly.