The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentratio...The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.展开更多
A yeast strain which was capable of degrading sulfonylurea herbicide chlorimuron-ethyl named as LF1 was isolated from a chlorimuron-ethyl contaminated soil near the warehouse of the factory producing chlorimuron-ethyl...A yeast strain which was capable of degrading sulfonylurea herbicide chlorimuron-ethyl named as LF1 was isolated from a chlorimuron-ethyl contaminated soil near the warehouse of the factory producing chlorimuron-ethyl in Shenyang City, Northeast China. The strain was identified as Sporobolomyces sp., based on its morphological and physiological characteristics and the phylogenetic analysis of 18S rRNA gene sequence. So far, this is the only yeast strain of Sporobolomyces sp. which is able to degrade chlorimuronethyl. Incubation tests showed that when the initial concentration of chlorimuron-ethyl in culture was 5 mg/L, LF1 could degrade more than 77% of the herbicide after incubation for 4 d at 30℃. The possible mechanism of chlorimuron-ethyl degradation by LF1 could be the acidic hydrolysis caused by the acids from the metabolism of the yeast strain. Further study should be conducted to examine the pathways of chlorimuron-ethyl degradation by LF1 and to approach the feasibility of using LF1 to degrade the chlorimuron-ethyl in soil system.展开更多
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB418506)the National Natural Science Foundation of China (No. 20337010+1 种基金40301022)the Key Laboratory of Environmental Engineering Foundation of Shenyang University (No. 04001).
文摘The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.
基金supported by the National Natural Science Foundation of China(No.30770405)the Knowledge Innovation Project of the Chinese Academy of Sciences(No.KSCX2-YW-G-053)
文摘A yeast strain which was capable of degrading sulfonylurea herbicide chlorimuron-ethyl named as LF1 was isolated from a chlorimuron-ethyl contaminated soil near the warehouse of the factory producing chlorimuron-ethyl in Shenyang City, Northeast China. The strain was identified as Sporobolomyces sp., based on its morphological and physiological characteristics and the phylogenetic analysis of 18S rRNA gene sequence. So far, this is the only yeast strain of Sporobolomyces sp. which is able to degrade chlorimuronethyl. Incubation tests showed that when the initial concentration of chlorimuron-ethyl in culture was 5 mg/L, LF1 could degrade more than 77% of the herbicide after incubation for 4 d at 30℃. The possible mechanism of chlorimuron-ethyl degradation by LF1 could be the acidic hydrolysis caused by the acids from the metabolism of the yeast strain. Further study should be conducted to examine the pathways of chlorimuron-ethyl degradation by LF1 and to approach the feasibility of using LF1 to degrade the chlorimuron-ethyl in soil system.
