【作者】 邓晓；

【导师】 廖晓兰；

【作者基本信息】 湖南农业大学 ， 农药学， 2003， 硕士

【摘要】 采用厌氧培养箱技术、MPN（最大或然数）和滚管计数法以及气相色谱技术，研究了湿地稻-鸭复合系统土壤中甲烷细菌的数量，有机磷杀虫剂甲胺磷和酰胺类除草剂乙草胺对该系统土壤中甲烷细菌数量及其活性的影响，以及甲胺磷在该系统土壤中的残留，同时对水稻田土壤中占优势的甲烷细菌进行了分离纯化。旨在为全面评价稻-鸭复合系统提供理论基础和实践依据，同时为协调粮食生产和环境保护之间的矛盾，寻求理想的稻田甲烷减排措施和农业可持续发展道路奠定理论基础。本试验主要研究结果如下： 1．湿地稻-鸭复合系统土壤中甲烷细菌数量研究。目前为止，有关这方面的研究尚无报道。研究结果表明：稻-鸭复合生态系统（不施农药，养鸭）和对照（长期施用农药，不养鸭）土壤中甲烷细菌数量变化规律与稻田甲烷排放的季节变化模式基本一致。早稻田土壤中菌数高峰期出现在分蘖盛期和孕穗期，晚稻田土壤中出现在分蘖盛期，实行稻鸭复合种养显著降低了稻田土壤中甲烷细菌数量，特别是减少了甲烷排放高峰期的甲烷细菌数量。早稻和晚稻MPN计数中，分别比对照降低20％～96.9％和94.3％～95.8％，早稻滚管法计数中比对照降低33.3％～98.1％。从而证实了甲烷细菌数量是决定水稻田中甲烷释放量的主要因素之一。 2．早稻田土壤中占优势甲烷细菌的分离。结果表明：从湖南省长沙县水稻田土壤中分离到四株优势的甲烷细菌菌株，分别定名为201，202，203和204菌株，它们具有不同的形态和生理特性。其中201，202，203菌株的单个菌落呈圆形，204菌株呈不规则形。在420nm光波激发下，201和204菌株产生黄色荧光，202和203菌株产生蓝色荧光。201和202菌株能利用H₂／CO₂、甲胺、乙酸钠、异丙醇和甲酸作为生长和产甲烷的基质，202菌株还能利用甲酸；203和204菌株能利用H₂／CO₂、甲胺和甲醇，203菌株还能利用异丙醇，204菌株还能利用乙酸钠；201和204菌株的最适生长pH为6.5，202菌株的最适生长pH为7.5，203菌株的最适生长pH为8.0；201菌株的最适生长温度为35℃，202和204菌株最适生长温度为40℃，203菌株最适生长温度为45℃。 3．甲胺磷和乙草胺对稻-鸭复合系统土壤中甲烷细菌数量及其活性影响的研究。结果表明：甲胺磷浓度分别为0.1，0.2，0.5，1.0mg／kg时，加药后7d内对产甲烷菌的生长表现出刺激作用，数量增加0.2～44.1倍，每管的产甲烷量增加0.8～2.1倍，且随着药剂浓度的增加，刺激产甲烷菌的生长繁殖作用逐渐增强；相同四种浓度的乙草胺在加药后7d内，甲烷细菌的生长受到抑制，数量下降了50％～99％，每管的产甲烷量减少2.9～107倍，且这种现象随着药剂浓度的增加而趋于明显。随着加药时间的延长，产甲烷菌数量及其活性又逐渐恢复至原有水平。作者认为甲烷细菌是一种对农药非常敏感的细菌。 4．甲胺磷在稻-鸭复合系统土壤中残留量的研究。检测结果表明，稻-鸭复合系统土壤中未检出甲胺磷的残留，而长期施农药的常规稻作系统土壤中甲胺磷的残留量达0.39mg／kg。说明通过长期围栏养鸭的稻田可清除土壤中农药的残留。因此作者认为长期施用甲胺磷有可能是导致甲烷排放量及产甲烷菌种群数量增加的原因之一。更多还原

【Abstract】 The study adopted the technology of anaerobic culture case technique, MPN(most probable number) and roll tube methods, and gas chromatography to survey the amounts of methanogens in soil of rice-duck complex ecosystem of wetland, the influence of methamidophos and acetochlor on the amounts and activity of methanogens in soil of this system, the residual quantity of methamidophos in soil of rice-duck complex ecosystem of wetland, and the segregation and cultivate characteristic of dominant methanogens in paddy fields. It aimed at affording scientific basis for coordinating the conflict between rice production and environmental protection, and searching for ideal measure to mitigate methane emission and achieve agricultural sustainable development. Main results for this study are as follows:1. The study on the amounts of methanogens in the soil of rice-duck complex ecosystem of wetland.There is no report in this respect so far. The results indicated: The seasonal change pattern of the amounts of methanogens in the soil of rice-duck complex ecosystem of wetland and CK (ordinary system ) was consistent with that of methane emission law of paddy fields. The amounts were the greatest at active tillering stage and booting stage for early rice, and the amounts were the greatest at active tillering stage for late rice. Rice-duck complex planting and breeding pattern greatly decreased the amounts of paddy fields, especially decreased the amounts of methanogens during methane emission peak period. The amounts of that in the soil of early rice and late rice were decreased 20%~96.9% and 94.3%~95.8% by the MPN method, the amounts of that were decreased 33.3%~98.1% for early rice by the roll tube method. It confirmed that the amount of methanogens was the one of main factors of amount of methane emission in paddy fields.2. The study on the segregation and characterization of dominant methanogens in paddy fields.The result showed: Four strains which were dominant were isolated from the soil of early rice at the experiment farm in Changsha County of Hunan Province by anaerobic culture case and roll tube method, and were named strain 201, 202, 203and204. There were different morphology and physiological characteristic. The colony of strain 201, 202 and 203 were round, and colony of strain 204 was notregular, strain 201 and 204 brought about yellow fluorescence, but strain202 and 203 brought about blue fluorescence. Strain 201 and 202 could use H2/CO2, nonemethylamine, sodium acetate, isopropanol and formate, strain 202 could also use methanol; strain 203 and 204 could use H2/CO2, nonemethylamine, methanol, strain 203 could also use isopropanol, strain 204 could also use sodium acetate. The optimum pH of strain 201 and 204 was 6.5,that of strain 202 was 7.5, and that of strain 203 was 8.0. The optimum temperature of strain 201 was 35 ,that of strain 202 and 204 was 40 ,and that of strain 203 was 45 .3. The influence of methamidophos and acetochlor on the amounts and activity of methanogens in the soil of rice-duck complex ecosystem of wetland.The result indicated: when the concentration of methamidophos solution was 0.1, 0.2, 0.5, l.0mg/kg respectively, the growth of methanogens was stimulated in 7 days, the amounts of that increased 0.2-44.1 times, and the production of methane per tube was increased 0.8-2.1 times. The growth of methanogens was obviously inhibited in 7 days at four concentration of acetochlor solution, the amounts of methanogens were decreased 50%~99%, and the production of methane per tube was decreased 2.9-207 times. The stimulating and retarding effect was more obvious with increasing concentration of methamidophos and acetochlor solution respectively. With prolonging of time adding pesticide, the amounts and activity of methanogens had recovered normal level step by step. Author suggested that methanogens were sensitive bacteriums on pesticides.4. The study on the residual quantity of methamidophos in the soil of rice-duck complex ecosystem of wetland.The result showed: there更多还原