Virus Identification On Chrysanthemun Morifolium And Evaluation Of Biological Characteristics And Quality Of Virus-free Seedlings

Chrysanthemum (C. morifolium Ramat.) has a long planting history in China. Tongxiang City is the cradle of C. morifolium. It is also one of the eight well-known herbs "Zhe Ba Wei".In this study, virual particles were isolated from plants obtained in Zhejiang Province and detected by electron microscopic, RT-PCR and DAS-ELISA. Healthy virus-free seedling were obtained. The effects of virus elimination process on plant biological characteristics and quality were evaluated.Main results are listed as follows:(1) Several special zones in Tongxiang Ctiy were investigated. Some important cultivation bases were seriously infected with virual disease. Infected plant showed symptoms with leaf variegation, vein clearing, few branches resulting in a decreased yield and quality of Chrysanthemum morifolium.(2) Virus particals were detected in TEM. The particals were linear,600-700nm in length. DAS-ELASA test showed positive result. Gene sequence analysis test showed that the length of Chrysanthemum Virus B (CVB) coat protein was982bp, DNA sequence similarity was92%with Serial Number EU499736.1in NCBI.The pathogen infected C. morifolium in Zhe jiang Province were confirmed with CVB.(3) The establishment of the rapid propagation system was developed from "Mulapicesle Step".The best treatment for sterilization was that the explant were dripped in75%ethanol for30s, then in0.1%HgCl2solution for12min. The survival rate was70%. The optimized medium for the growth of stem cuttings was basic medium MS supplemented with0.1mg/L6-BA and0.1mg/L NAA. The optimized medium for the rooting of plantlet was half strength of MS supplemented with0.1mg/L NAA and the rooting rate was100%. When the aseptic seedling reached5cm height and roots attaining1cm or so, they were transplanted to greenhouse with100%survival rate. The size of shoot apices was about0.3-0.5mm. They were differentiated into callus after25days then into seedlings. The survival ratio of shoot apices was10%. Field performances revealed that there were significant difference between virus-free seedlings and susceptible seedlings in effective number of flowers, branching numbers, the relative content of chlorophyll. The yield of virus-free’Zao xiao yang ju was490.1kg per mu,’Xiao yang ju’was1083.3kg per mu, increased by11%,29%, respectively. The content of total flavonoids in’Zao xiao yang ju’and’Xiao yang ju’were70.41mg/g,63.94mg/g, respectively. Susceptible "Zao xiao yang ju’and ’Xiao yang ju’were53.44mg/g,43.41mg/g, respectively.The content of chlorogenic acid in’Zao xiao yang ju’and’Xiao yang ju’were2.71mg/g,2.13mg/g respectively. Susceptible’Zao xiao yang ju’and’Xiao yang ju’were1.62mg/g,1.01mg/g, respectively.