驯化小麦根际土壤中甲磺隆生物降解潜力研究

Biodegradation potentiality of metsulfuron-methyl in acclimated wheat rhizospheric soil

通过HPLC测定土壤中甲磺隆残余浓度，研究甲磺隆驯化／未驯化的小麦根际／非根际土壤中甲磺隆的降解规律．结果表明：土壤中甲磺隆的降解遵循一级反应动力学模型，降解速率常数约为0．037～0，020d，丰衰期约为18．7～34．7d．种植过小麦的土壤极大地促进了甲磺隆降解，根际与非根际土壤中甲磺隆降解速率常数差异显著，各处理均达到了0．05的差异显著水平．甲磺隆驯化提高了土壤中微生物对甲磺隆的降解能力，第20d，驯化土壤中甲磺隆去除率高出对照土壤约6％～12％．土壤中甲磺隆浓度越低，其降解速率越快．这为利用植物根际加快土壤中磺酰脲类除草剂的降解研究提供了理论依据．

The degradation of metsulfuron-methyl in different soils, including acclimated and/or original wheat soil, rhizospheric and/or non-rhizospheric soil, was investigated by determining its residual concentration with HPLC. The results show that the degradation dynamics of metsulfuron-methyl in soil fitted to the first order reaction kinetics, the degradation rate constant was about 0. 037-0. 020 d^-1 and the half life was about 18.7-34.7 d. The soil, which had been planted wheat previously, promoted the degradation of metsulfuron-methyl significantly. The difference of degradation rate constant between the rhizospheric and non-rhizospheric soil was significant at the 0.05 probability level. The biodegradability of microbe was enhanced by domestication. On the 20th day, the removal rate of metsulfuron-methyl in the domesticated soil was higher 6 to 12 percent than that without domestication. Furthermore, the low concentration of metsulfuron-methyl was benefit for its degradation, the degradation rate constant of metsulfuron-methyl increased with its concentration reducing. The result above provides a theoretical feasibility for accelerating the degradation of the sulfonylurea herbicides in plant rhizospheric soil.