Studies On The Identification And Biological Character Of Some Fungus-related With Two Diseases Of Medicinal Plants

Polygonatum odoratum and Gentian are 2 important medicinal plants. Polygonatum odoratum is the dry roots of Polygonatum odoratum (Mill.) Druce. Gentian is the dry roots of Gentiana scabra, G. triflora, G manshurica, G. rigescens. And they are widely distributed and rich in natural resources in China. Polygonatum and Gentian are traditional Chinese medicine and they have thousands of years of medication history in China. As a high medicinal value, the planting regions of two plants are extending, but the diseases of Polygonatum and Gentian are increasing in recent years. For the disease and theirs prevention are extremely important.In this study, fungi are isolated from the leaves of Polygonatum, which infected Polygonatum odoratum brown patch. The strain is denominated z-1. It is identified as Fusarium acuminatum by observation of colony morphology and analysis of ITS1-5.8S-ITS2 rDNA region sequence. This is the first reported of Fusarium acuminatum causes Polygonatum odoratum brown patch. Further study, including of the biological characteristics of Fusarium acuminatum, chemical control and its inhibition of antagonistic bacteria, are developed.The experiments of Fusarium acuminatum under different carbon nitrogen nutrition and environmental cultural condition were conducted. The optimal cultural conditions is growing at 28℃; the strain adapts to a wider scope of the pH, but colony growth was the best at about pH 6.0-8.0; Light had no significant effect on mycelial growth. The treatment of whole illumination could restrain the growth of mycelium, the alternation of darkness and light could promote mycelium growth. In a variety of carbon sources tested, the growth of colony was the best with soluble starch as the carbon source and the worst with monosaccharide (D-fructose, D-galactose). In a variety of nine species nitrogen sources, the hyphae could grow. But the type of nitrogen for the growth of tested strains is different. When Glycine and NH4Cl as a nitrogen nutrition for hyphae growth are the best and worst, respectively.With the eight major categories,23 kinds of fungicides on the mycelia of the inhibitory tests, it showed that the fungicides except fenaminosulf inhibited the growth of Fusarium acuminatum. Mancozeb in organic fungicides and Metalaxyl-M mancozeb in fungicide mixtures had strongly inhibitory on Fusarium acuminatum. The rate of restraining is 76.7% and 73.3%. Amobam in organic fungicides and Pyraclostrobin in Fungicide-triazole, which is diluted 900 and 2000 times, could inhibit the growth of Fusarium acuminatum. Pyraclostrobin is stronger than Amobam in Virulence Intensity.In the control efficacy of Trichoderma and two Bacillus subtilis, they can inhibit the growth of pathogens. The inhibitory effect of Trichoderma is slightly worse than Bacillus subtilis. The inhibition of Bacillus subtilis Dc10 is the best.Two fungi are isolated from Gentian leaves infected Gentian leaf spot. They are identified as Alternaria tenuissima (Fr.) Wiltshire and Alternaria alternata. The fungi are inoculated for healthy leaves, pathologic systems are not found. The previously reported pathogen for Gentian leaf spot, such as Septoria gentianae, could not be isolated.