Study on Identification & Biological Characteristics and Isozyme of Root Rot in Ligusticum Chuanxiong
|School||Sichuan Agricultural University|
|Keywords||Chuanxiong Root rot Eggplant rot Fusarium Identification of the pathogen Biological characteristics Prevention and cure Isoenzyme activity|
Chuanxiong for Umbelliferae (Umbelliferae) Wara this genus dry rhizome Chuanxiong (Ligusticum chuanxiong Hort), is famous Sichuan production geoherbs, with nearly two thousand years of planting and use of history. Chuanxiong root rot [Fusarium solani (Mart) Sacc] is an important disease of Dujiangyan City, Sichuan Province, Chuanxiong planting bases in 2006, the incidence of the disease field strains was 6.08% to 45.47%, 23.61% on average, serious illness Tian 68.46%, causing serious harm, and has become the main diseases in the film area Chuanxiong. This test is Chuanxiong root rot symptoms, pathogen identification, biological characteristics, Fungicide screening and field chemical control and isoenzyme activity, the results are as follows: 1 Chuanxiong root rot symptoms Chuanxiong root rot is a species of soil-borne diseases, the Chuanxiong throughout the growing season will occur. Early onset ground began to fade from the outer leaves yellow, and gradually extended to the heart leaves. The underground tuber disease Ministry early brown to reddish brown, some become water-soaked, as the disease progresses, the diseased plant tip, leaf margin began to scorch. Susceptible tuber pith black and upward development, gradually shallow brown. Late susceptible tubers internal rot, was brown pasty, with special smell, soft rot shape; Finally, the whole plant to stop growing, dead. Chuanxiong root rot isolated by the Organization of the isolation and culture traits chuanxiong root rot fungus pure culture. Basically consistent with the morphological characteristics of all isolates on PDA plates, 2d after white to light gray mycelium 3d sporulation, the mycelium separated floc colonies positive concentric Physalospora, colony opposite was lavender. 3 isolates tieback and pathogen identification at room temperature, with a conidia suspension Baptist roots inoculated Chuanxiong the roots, back to the 15d pick plants overall incidence of symptoms of the same symptoms of the field, while CK is not the disease. Conventional separation of the same bacteria isolated again from the site of disease. Thus proving the isolates Chuanxiong root rot pathogens. According to the morphological characteristics of the pathogen, the culture traits observed and rDNA-ITS sequence analysis. Hyphomycetes), the tumor seat spore head (Tuberculariales),, the tumor Block the spore Division (Tuberculariaceae), Fusarium (Fusarium). Chuanxiong root rot caused by [Fusarium solani (Mart) Sacc] first reported at home and abroad. Chuanxiong root rot fungus biological characteristics of the study clearly a different medium, carbon sources, nitrogen sources, temperature, pH, and light Chuanxiong root rot fungus mycelium growth, sporulation, and spore germination impact. In a different medium, the pathogen mycelial growth and sporulation of the best in the PSA; soluble starch medium on mycelial growth of the worst; sporulation worst PS medium; temperature suitable for 25 ~ 30 ℃ mycelial growth, the optimum temperature of 28 ℃, below 10 ° C or higher than 40 ℃ are interested in spore germination inhibition produced high temperature will cause the spores deformity; suitable for the growth of pathogenic bacteria at pH 5 to 8, the most the fitness growth pH6 pH is too low or too high will cause the pathogen growth; different light conditions of processing: the impact of various treatments on mycelial growth and sporulation was no significant difference; mycelial growth optimum carbon source was sucrose sporulation optimum carbon source fructose, lactose worst; the mycelial growth grow best on potassium nitrate, ammonium sulfate growth worst, beef extract the sporulation best ammonium chloride sporulation worst. Spore germination optimum temperature of 20 ° C to 35 ° C; optimum 28 ° C, RH from 90 percent to 100 percent, and water droplets could germinate, water droplets best, less than 90% germination; suitable pH 5 ~~ best pH6, the germination rate of 71.73%, higher than the pH does not germinate; the conidia lethal temperature of 53 ° C. 5 Fungicide screening and chemical control of the field of eight kinds of medication (root rot fungus, cards bacteria Dan, the root will rule, thiophanate-methyl, mancozeb, chlorothalonil, bacteria Fenaminosulf One, ground systems grams) screening The results showed that the inhibitory effect on mycelial growth and sporulation is the root must be put to the best, thiophanate-methyl, reached a significant level (colony diameter of 2.20cm and 1.75cm, sporulation of 0.92 × 10 ~ 7 / dish and 0.68 × 10 ~ 7 / dish); of chlorothalonil and root rot spiritual pathogenic fungi followed (colony diameter of 2.93cm and 3.30cm, sporulation of 0.52 × 10 ~ 7 / dish and 1.8 × 10 to 7 / dish); 1 Fenaminosulf, and cards bacteria Dan has no inhibitory effect on the pathogen. The inhibitory effect of the pathogen conidia best chlorothalonil, mancozeb, inhibit the germination rate of 100%; roots will rule, the ground bacteria President grams, of root rot spiritual followed inhibit the germination rate of 99.8% , 99.5% and 98.7%; 1 Fenaminosulf,, and cards bacteria Dan conidia germination inhibition of the poor, only 30.4% and 14.6%. The selection of the four kinds of pharmaceutical field efficacy trials, Chemical Control: chlorothalonil, mancozeb, thiophanate-methyl, and the root will rule plant rate and control efficiency are extremely significant. The isoenzyme test the 6 eggplant rot Fusarium impact Chuanxiong isoenzyme activity that: after inoculation, POD activity of performance for the first rising and then falling trend reaches its maximum at 7 d after inoculation, the peak of 274.335 for the 5.43 times that of the control, and then slow down to 12 d decreased to control levels, while the change of control has been relatively stable. PPO enzyme activity showed the trend of first rising and then falling, 4d after inoculation when the activity began to increase to 7 d, the peak was 2.82 times, followed by a gradual decline, to the first 9 d reached the maximum two peak, to 76, and then decreased gradually decreased to control levels by 12 d, and the change of control has been relatively stable.