| Rice false smut is the most important fungal diseases in head of the rice. Chlamydospores are the important preliminary infection sourses of the disease. This paper mainly studied germination percenntage of chlamydospores, the melanin in their wall, fatty acid in wall and in cell, and microorganism around them in soil. In order to reveal the relationship between the germination of chlamydospores and the melanin in the wall of chlamydospores, fatty acid in wall and in cell, microorganism around the chlamydospores in soil. The result is the theoretical basis for fungicide design and controlling the disease.The main research results are followed:Melanin extraction of the black and yellow chlamydospores wall in U. virens was conducted by HCl and NaOH with the orthogonal tests using 3 factors and 3 levels. The result showed that the NaOH extraction method was better than HCL, and the former optimum condition was 3moL/L NaOH, 2moL/L HCL and 80℃water bath for120min.Yellow and black chlamydospores collected in Sep,2009 was kept in indoor, on the soil surface and 5cm under the soil. The initiative germation percentage of yellow chlamydospores in indoor was the 19.6%, melanin content was 92.4μg/0.05g, while black chlamydospores was 1.4%, melanin content was 35μg/0.05g. In Nov.2009, Mar., May, July,2010,the germation of yellow chlamydospores were 9.4%,0.4%,1.1% and 10%, respectively, which melanin contents associated with germination stages were seperately 189.4μg/0.05g,285.4μg/0.05g,217.8μg/0.05g and 168.2μg/0.05g. In same above 4 stage, black chlamydospores was the 1.1%, melanin content was 775.9μg/0.05g,,. the germation percentage of yellow chlamydospores was, melanin content was 285.4μg/0.05g, while black chlamydospores was the 0, melanin content was830.2μg/0.05g. the germation of yellow chlamydospores was the1.1%, melanin content was 217.8μg/0.05g, the germation of black chlamydospores was the 0, melanin content was817.6μg/0.05g. the germation of yellow chlamydospores was the10%, melanin content was 168.2μg/0.05g, the germation of black chlamydospores was the 1.4%, melanin content was805.5μg/0.05g. Therefore, content of melanin in different colour chlamydospores wall with the germination percentage of chlamydospores reducing, was increasing. And the content of melanin in black chlamydospores is much more than that in yellow chlamydospores.3 methods, Saxhlet extraction, acid-hotting extraction method,organic solvent extraction process, extracting fatty acid were compared; The result showed that acid-hotting extraction in three methods was the best. Composition and content of saturated and unsaturated fatty acids of 3 types of chlamydospores wall, yellow, yellowish-green, black ones, and the whole chlamydospores in U. virens were tested by gas chromatograph-mass spectrometer. The result showed that with the colour of the chlamydospores from yellow to black, the content of saturated fatty acid in chlamydospores graduately reduced from the 28.87% to 24.04%, while the content of unsaturated fatty acid rise firstly, then reduced from 55.43% to 63.89%.The content of the stearic acid,one of the saturated fatty acid, was most in the walls of yellow chlamydospores, more in the walls of the Kelly ones, less in the walls of black chlamydospores.With the colour of chlamydospores from yellow to black, the content of the unsaturated fatty acid increased.In Sep2009/, two types of different colour chlamydospores were positioned on the soil surface and 5cm under the soil. The chlamydospores germation and amount of microbial flora around Chlamydospores were investigated at every two months intervals. The result showed that when the chlamydospores germination percentage is hightest,the amount of bactera was the lowest.From Nov to March 2010,with germation pencentage of the chlamydospores gradually falled, the amount of bacteria rised, In March 2010, the chlamydospores germination percentage is lowest, the amount of bacterium was highest。From March 2010 to July 2010,with the germination percentage was gradually increased, the amount of bacterium was gradually decreased. In 2009/9,when the germination percentage of chlamydospores is hightest,the amount of fungi was highest too..From November to March 2010,with germation pencentage of the chlamydospores gradually down, the amount of fungi decreased,.In March 2010,when the germination percentage of chlamydospores was lowest, the amount of fungi was also lowest. From March 2010 to July 2010, with the germination percentage was gradually increased, the amount of fungi was also gradually decreased. In Sep2009,when the germination percentage of chlamydospores is hightest,the amount of actinomycetes was lower.From Sep to Nov,with germation pencentage of the chlamydospores gradually down, the amount of actinomycetes rised to highest.From Nov to March 2010. with germation pencentage of the chlamydospores gradually decreased, the amount of actinomycetes fell from highest to lowest. From March 2010 to July 2010, with the germination percentage gradually rised, the amount of actinomycetes also gradually increased. |
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