环氧虫啶在好氧土壤的归趋及对土壤微生物多样性的影响

发布时间：2018-08-02 16:31

【摘要】：环氧虫啶(cycloxaprid)是我国自主创制的手性新烟碱类杀虫剂,因其高杀虫活性而具有良好的市场前景。从对映体层面研究手性农药的环境行为和归趋是国际前沿研究的热点之一。本文采用同位素示踪和高通量测序技术,在光学异构体层面上,研究了14C-环氧虫啶两个对映异构体(1S2R-环氧虫啶,1R2S-环氧虫啶)和外消旋混合物(Racemic Mixture,RM)在酸性红砂土S1、中性黄松土S2及碱性滨海盐土S3中的归趋及对土壤微生物多样性的影响,主要结果如下： (1)好氧培养过程中,环氧虫啶两种对映体及消旋体在三种供试土壤中的可提态残留(Extractable residue,ER)、结合残留(Bound residue,BR)及矿化均无显著差异。可提态残留随培养时间不断下降,在不同土壤中呈现S1S3S2的规律；结合残留和矿化则不断上升,在不同土壤中分别呈现S2S3S1和S3S2S1的规律。环氧虫啶在三种土壤培养100d后,ER分别下降至占放射性引入量的36.44%-38.08%、10.07%-10.81%和9.54%-15.47%,BR上升至占引入量的56.84%-61.22%、79.55%-82.99%和66.80%-68.90%,矿化量为引入量的0.22%-0.23%、6.69%-7-31%和14.82%-17.06%。 (2)好氧和淹水培养100d后,环氧虫啶两种对映体及消旋体在的三种供试土壤中的矿化、可提态残留、结合残留及其在腐殖质中的分布均无手性选择性。对比不同培养方式,环氧虫啶在好氧的S2和S3中产生的矿化量明显高于同种淹水土壤,并且更倾向于形成结合残留；在S1中两种培养方式矿化均小于1%,结合残留量最小且差异不显著。环氧虫啶在三种土壤好氧和淹水培养100d形成的结合残留在土壤腐殖质中的分布均呈现富啡酸胡敏素胡敏酸的规律。 (3)环氧虫啶对映体在三种供试土壤中好氧培养100d后,对土壤细菌多样性的影响无手性选择性差异。三种土壤原生细菌的多样性差异明显,且施药后对S1中细菌的种类和相对丰度影响较大,对S2和S3的影响较小。研究结果证明手性杀虫剂环氧虫啶在土壤中的行为归趋及对土壤微生物多样性的影响均不存在对映体选择性。
[Abstract]:Epoxidin (cycloxaprid) is a chiral new nicotinic insecticide, which has a good market prospect because of its high insecticidal activity. Enantiomeric study on the environmental behavior and fate of chiral pesticides is one of the hot topics in the international frontier. In this paper, isotopic tracer and high throughput sequencing techniques are used in the optical isomer level. The effects of two enantiomers (1S _ 2R -epoxycytidine) and Racemic mixture (R _ 3) on soil microbial diversity in acidic red sandy soil, neutral pine soil S _ 2 and alkaline littoral saline soil S3 were studied. The main results were as follows: (1) during aerobic culture, there were no significant differences in Extractable residueto ER, Bound residuebur and mineralization between two enantiomers and racemes. The extractable residue decreased with the culture time and showed the law of S1S3S2 in different soils, and the law of S2S3S1 and S3S2S1 in different soils was observed in combination with residue and mineralization. After 100 days of cultivation in three soils, ER decreased to 36.44 and 10.07-10.81% and 9.54-15.47m, respectively, and rose to 56.84-61.222-82.99% and 66.80-68.90, respectively. The mineralized amount was 0.22-0.236.69-7-31% and 8214.-17.06, respectively. (2) after 100 days of aerobic and flooded cultivation, the mineralizing amount was 0.22-0.236.69-7-31% and 82-17.06um. (2) after 100 days of cultivation of aerobic and flooded water, the mineral amount was 0.22-0.236.69-7-31% and 82-17.06. (2) after 100 days of aerobic and flooded cultivation, the mineral amount was 0.22-0.236.69-7-31% and 8214.-17.06, respectively. There was no chiral selectivity in mineralized extractable residues binding residues and their distribution in humus of two enantiomers and racemes in the tested soils. Compared with different culture methods, the mineralized amount of epoxidin in aerobic S2 and S3 was significantly higher than that in the same flooded soil, and it was more inclined to form binding residues. In S1, the mineralization of the two cultures was less than 1, and the binding residue was the least and the difference was not significant. The distribution of residual residues of epoxidin in soil humus was similar to that of humic acid (Hu Min). (3) the enantiomers of epoxidin were cultured in three kinds of soils for 100 d after aerobic culture, and the distribution of the residues in soil humus was similar to that of humic acid. (3) after 100 days of aerobic culture in three soils, the distribution of epoxidin enantiomers was similar to that of humic acid. There was no difference of chiral selectivity in soil bacterial diversity. The diversity of the three soil protobacteria was significantly different, and the species and relative abundance of the bacteria in S1 were significantly affected by the application of insecticides, but the effects on S2 and S3 were relatively small. The results showed that there was no enantioselectivity of chiral insecticide epoxidin in soil.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S482.3;S154.3

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