| Ligusticum chuanxiong belongs to Umbelliferae of Ligusticum L.It is famouse mainland medicinal materials in Si-chuan province,it has two thousands growed and used history.The Ligusticum chuanxiong root rot was severity disease in Du-Jiang Yan basement of Si chuan province.In 2006,the percentage of the disease reached 6.08%～45.47%,the average was 23.61%,which caused the decline and death of the Ligusticum chuanxiong.The dissertation included the symptom characteristics,the identification of pathogen,the biological characteristics,the fungicides screening in Laboratory for Ligusticum chuanxiong root rot and the POD,PPO isozyme activity.1 The sympyom characteristics of Ligusticum chuanxiong root rotThe original symptoms indicated aboveground leaf fading and yellowing,underground tuber presented brown and mahogany,The later symptoms indicated tuber rot inside,presented filemot,finally,the whole plant stoped growing and die.2 Isolation and cultural characteristics of Ligusticum chuanxiong root rotIsolate the diseased root,and gain the pathogen.The pathogen is cultured on PDA medium,the colony is white,circular,and purple later.The spores begin to be produced after 3 days and the pile of spores is white.3 Inoculation and identificationThe diseased symptom and the pathogen characteristics of inoculated plant,were similarly to the diseased plant in field.It is improved that the isolating was the pathogen of Ligusticum chuanxiong root rot.After the morphological characteristics and the sequence of ribosomal DNA-ITS,the pathogen was identified as Fusarium solani(Mart)Sacc.3 Biological characteristicsThe pathogen[Fusarium solani(Mart) Sacc.]of Ligusticum chuanxiong root rot.can produce many spores and grow best on PSA from different media.There are 7 kinds of carbon and nitrogen sources,which are best for the mycelial growth and spore production,the optimum C source were sucrose,spores occurr on fruit sugar media.Among nitrogen sources, potassium nitrate is the best for mycelial growth.The spore formation is best on beef extract. For the growth and ascospore production of it,the best medium was PSA,the optimum temperature was 28℃and the optimum pH was 6.Whole light promote spore formation.For spore germination of the pathogen,the optimum temperature and relative humidity(RH) are 20～35℃and 90%～100%,respectively,and the best condition is 28℃and in drops of water.The spores faile to germinated at temperatures higher than 40℃or lower than 10℃and at an RH of＜90%.The optimum pH for spore germination is in the range of 5～7,and the spores faile to germinate at pH higher than 8.The spores will be killed at or over 53℃.5 Select fungicides and field trialThe inhibiting effects of 8 fungicides on Fusarium solani(Mart) Sacc.,the results demonstrated that the best fungicides of inhibiting the the mycelia growth and spores formation are Genbizhi and thiophanate methyl,the second are chlorothalonil and fenmaminofulf,the worst are fenmaminofulf-fulphuy and Kajundan.The results demonstrats that the best fungicides of inhibiting conidial germination are chlorothalonil and mancozeb,the percentage of spore germination are both 100%;the second are Genbizhi,bactericide and fenmaminofulf,the percentage of spore germination are 99.8%,99.5%and 98.7%;the worst are fenmaminofulf-fulphuy and Kajundan.,the percentage of spore germination are 30.4%and 14.6%.Field control had demonstrated that 4 fungicides are all markedness,thiophanate methyl and Genbizhi are lower it.6 Isozyme activity's variety of Ligusticum chuanxiong damaged by Fusarium solani(Mart) SaccIsozyme activity dissertation showed that:After inoculability,POD isozyme activity's variety ascended firstly then descended,it reached max after 7 days,the peak value was 274.335,5.43 multiple than antitheses,it came down as antitheses after 12 days,the antitheses calmly during those period.PPO isozyme activity's variety ascend firstly then descend,it became accretion after 4 days,reach max at 7th day,the peak value was 2.82 multiple than antitheses,it appeared second peak value at 9th day,12 days later it came down as antitheses. the antitheses calmly also.
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