| According to the unique UV absorption of different pathogens's toxin,the relation model between the toxin production of the pathogens of Soybean Root Rot and its UV-value(ODT) was established as follows: With Fusarium:the toxin production(ug/ml)= -9.7895+1.5449 DT(F=319.0103 R=0.9846) With Rhizoctonia solani: the toxin production(ug/ml)= -6.9853+1.3009ODT(F=748.5542 R=0.9934)The effect of the cultural conditions (medium, temperature, aeration, pH, light), macroelements (C, N, P, K)and microelements (B, Mn, Mo, Cu, Zn)on the pathogen's sporulation, mycelium growth and toxin production were studied.on the basis of the results the control methods for Soybean Root Rot could be derived.The sporulating of Fusarium in the cultural medium of PD and PSC was better than in the Richard and Ceapek.with the temperature raised from 5℃to 30℃the spore numbers of the pathogen increased.when the pH in medium increased from 5 to 8,the sporulating of F.oxysporum was weakened and the sporulating of F.solani was promoted.it is inverse relation between the sporulation and aeration. it had a inhibital effect for sporulation when Cu, Zn increased. But Mn, Mo, Cu have a promote role for it.The cultural conditions with PD and PSC,30℃,pH=6 to 7,the shake frequency in 40 to 80r/min and the macroelements treatment with C30N15P1K0.5 was best for its sporulation.It was good for Fusarium's sporulation when Mn was 30mg/L,Mo was 0.8mg/L,Cu was 1.8mg/L in the medium.The mycelium growth of Fusarium was best in PSC, 25℃~30℃, pH=7.N content was higher in the medium the mycelium growth was better.and it was inhibitied by Mn, Mo, B.the cultural conditions with PSC,25℃,pH=7,the shake frequency in 120~160r/min and the macroelements treatments with C30N15P0.5K1 and C20N15P1.5K1.5 were good for the mycelium growth. The toxin produceion of Fusarium was best in PSC, with the temperature raised from 5℃to 30℃the toxin production increased,meanwhile the toxin production increased as the pH raised from 3 to 7.and it could be promoted by a good aeration .the toxin production was promoted by the N concent in the medium and inhibited by Mn, Mo and B.the cultural conditions with PSC,25℃,pH=7,the shake frequency in 160r/min and the macroelements treatments with C20N15P0.5K0.5,C40N15P0.5K0.5 and C20N15P1K1 were good for the toxin production. For the Rhizoctonia solani,the experimental results showed that the mycelium growth and toxin production increased with the temperature raised from 5℃to 25℃,and pH from 5 to 7,and with a good aeration. The toxin production was inhibitied by Mn, Mo and B. the cultural conditions with Richard,30℃,pH=7,the shake frequency in 80r/min, the macroelements treatments with C20N15P1.5K0.5 and Cu with 1.8mg/L,Zn with 1.2mg/L were good for its mycelium growth.the cultural conditions with Richard,20℃,pH=8,the shake frequency in 80r/min, the macroelements treatments with C30N15P1K1.5 and Cu with 1.8mg/L,Zn with 1.2mg/L were good for its toxin production.The sporulation, mycelium growth and its toxin production of the pathogens have different role in the disease.we use the comprehensive index to measure the total effect of those factors mentioned above.On the basis of the comprehensive index, the best culture conditions for Fusarium were PSC,25℃~30℃,pH=6 to 7,the shake frequency in 160r/min and the macroelements treatments with C30N15P1.5K1.5. The inhibiting of conditions were Richard,15℃,pH=9,stationary training and the macroelements treatments with C20N5P0.5K0.5.the best culture conditions for R.solani were Richard,25℃~30℃,pH=7,the shake frequency in 80r/min and the macroelements treatments with C20N15P1.5K1.5. The inhibiting of conditions were Ceapek,15℃,pH=5, the macroelements treatments with C20N5P0.5K0.5.It have a significant inhibitory effect for the sporulation, mycelial growth and toxin Production of pathogens of Soybean Root Rot when Mn was 60mg/L, B was 2mg/L, Mo was 0.8mg/L.
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