| Summary: | 碩士 === 國立臺灣大學 === 農業化學研究所 === 90 === This study is to investigate the fungicide, iprodione, in the environment, and how it affects on the soil bacterial community. Because general media give limited yield of bacterial and they cannot indicate the change of the whole soil bacterial community, the new technique PCR-DGGE is employed to research on the bacterial diversity.
The design of this study is to add iprodione recommend dose and ten times more concentrated than the recommended dose to the field (untreated addition of iprodione as control). The incubation temperatures were performed at 15 and 30℃. After apply- ing iprodione, samples were taken from enrichment cultures at different incubation days and then analyzed the residues of iprodione with HPLC. In order to compare the bacterial diversity from DNA, two different primers were used to run PCR, and the PCR product was analyzed with DGGE, the effect of iprodione on the soil community was discussed..
Degradation rate of iprodione at 30℃ was much faster than that at 15℃ in the autoclaved samples, the degradation rate is also affected due to different types of soil. Comparison with autoclaved and sterilized samples at incubation temperature of 15℃, the results showed that it was the main factor on degradation rate. DNA extracted from the samples which treated with iprodione was more than quantity of DNA that not treated with iprodione. This also reveals that microorganisms may degrade iprodione and utilize. Because the process of DNA duplication is affected by humic acid in soil, the yield of DNA is not as much as we expected. However, the bacterial community is effected by iprodione from the results of the DGGE fingerprinting. But the bacterial community had not changed a lot by iprodione treated samples. The same results were also showed in th soil samples collected from Da-hu and Kuan-Hsi. The soil of these two locations has been applied with iprodione for a long time, And bacterial communities restored the original state when iprodione was degraded completely in soil.
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