Allievi L, Gigliotti C
DISTAM, Sezione Microbiologia Agraria, Alimentare, Ecologica, Università degli Studi di Milano, Milan, Italy.
J Environ Sci Health B. 2001 Mar;36(2):161-75. doi: 10.1081/PFC-100103741.
Changes in aerobic bacteria and autotrophic nitrifier numbers, and in respiration and nitrification in two soils treated with cinosulfuron at 42 (field rate) and 4200 microg/kg were studied after 1 and 4 weeks of incubation under laboratory conditions. Only nitrification at 1 week was slightly inhibited by the cinosulfuron treatment, even at the field rate. In vitro toxicity tests carried out in agar media on representative aerobic bacteria, fungi and Azotobacter strains isolated from the two soils, as well as on nine collection soil bacteria, showed that only a very high cinosulfuron concentration (100 mg/l) can have negative effects on the growth of a limited number of soil heterotrophic microorganisms, under conditions similar to those of soil environment. The absence of three branched-chain amino acids increased bacterial sensitivity, thus showing the importance of the chemical conditions and suggesting acetolactate synthase enzyme blockage as the toxicity mechanism. It is concluded that cinosulfuron has a negative effect on only a few aspects of the microbial community in soil ecosystems, even at concentrations higher that those currently in use.
在实验室条件下培养1周和4周后，研究了用42（田间用量）和4200微克/千克的磺酰脲类除草剂处理的两种土壤中需氧细菌和自养硝化细菌数量的变化，以及呼吸作用和硝化作用的变化。即使在田间用量下，磺酰脲类除草剂处理在1周时也仅轻微抑制了硝化作用。在琼脂培养基上对从两种土壤中分离出的代表性需氧细菌、真菌和固氮菌菌株以及九种土壤细菌菌株进行的体外毒性试验表明，在与土壤环境相似的条件下，只有非常高的磺酰脲类除草剂浓度（100毫克/升）才会对有限数量的土壤异养微生物的生长产生负面影响。三种支链氨基酸的缺失增加了细菌的敏感性，从而表明了化学条件的重要性，并表明乙酰乳酸合酶酶的阻断是毒性机制。得出的结论是，即使在高于目前使用浓度的情况下，磺酰脲类除草剂也仅对土壤生态系统中微生物群落的几个方面有负面影响。
