Study On Biological Characteristics Of Alternaria Alternata And Electrophoresis Technique In The Classification Of Alternaria

This thesis mainly studies influence of growing to Alternaria alternata various kinds of environmental factors and nutriment and spore yield. And The polyacrylamicide gel electrophoretic analysis of isozymes and soluble proteins of 10 isolates in Alternaria alternata from tobacco were studied to compare their differences in isoenzyme zymogram and electrophoresis map. And the dynamic activity of enzymes excretived by pathogenic include cellulase,polyphenoloxidase,amylase were measured. The main results were as follows:1. The research of biological characteristic of Alternaria alternata shows that: the hyphae could grow in 10-35℃,the optimum temperature was in the range of 25-30℃, and the temperature lower than 7℃or higher than 40℃was not fit for the mycelial growth, the lethal temperature of conidial was 53℃and the lethal temperature of hyphae was 52℃. The pathogenic bacteria could grow under the condition of pH4.0-6.0,showing double peak curve,especially the optimum were pH 6and pH 8.0. The optimum pH of produce conidial was 6.0. The optimum pH of yphae was 6.0. The pathogen could use many carbohydrate and nitrogen sources,but the optimum carbon sources were glucose,maltose and lactose, The optimum medium for conidial production was maltose and the result of the growth of Alternaria alternata in liquid medium showed that fructose and maltose,as a sources of carbon , were more optimum for mycelial growth; the optimum nitrogen sources were peptone. Peptone was optimum for mycelial growth and conidial production. Urea and NH4Cl has some inhibitory action to pathogenic growth. It is benefit for mycelial growth and concidial production under the condition of alternateing between illumination and darkness.2. The polyacrylamicide gel electrophoretic analysis of isozymes and soluble proteins of 10 isolates in Alternaria alternata from tobacco were studied to compare their differences in isoenzyme zymogram and electrophoresis map. Then hierachical clustering method was employed to analyse the results of electrophoresis.The results showed that there were clear differences in soluble protein eletrophoresis map in species and between different isolates in Alternaria,and that 10 strains were divided into five groups. It is suggested that soluble protein electrophoretic technique was a useful tool in the classification of Alternaria sp. and could be used to classify Alternaria sp. on both specific and intraspecific ranks.3. The activities of cellulase,polyphendoxidase,amylase excreted from the pathogenic cell were tested and analysed respectively in 10 days after treatment in liquid medium. The results showed that three enzymes activities was gradually rise along with the time on incubation. The activities of cellulase,polyphendoxidase excreted from the pathogenic cell in GuoYang area were apparent higher than other areas. The activities of cellulase,polyphendoxidase excreted from the pathogenic cell in FengYang was low all along.But the activitie of amylase excreted from the pathogenic cell in FengYang was higher than other areas.