高效氟吡甲禾灵对潮土微生物呼吸及酶活性的影响

Impact of haloxyfop-R-methyl on microbial respiration and enzyme activities in fluvio-aquic soil

为了探究除草剂——高效氟吡甲禾灵对土壤生态系统的毒理效应,采用室内培养法,设置对照(CK)、0.01 mg·kg^(-1)(T1)、0.04 mg·kg^(-1)(T2)、0.08 mg·kg^(-1)(T3)、0.16 mg·kg^(-1)(T4)、0.40 mg·kg^(-1)(T5)6个处理,研究不同浓度高效氟吡甲禾灵对土壤呼吸强度和酶活性的影响。结果表明:除T1处理显著促进土壤呼吸外,在培养第7 d和14 d时T2和T3处理显著抑制了土壤呼吸;T4处理在第7 d时抑制土壤呼吸,之后转为激活;T5处理在培养前14 d与CK基本持平。高效氟吡甲禾灵显著抑制了土壤蔗糖酶的活性,且抑制程度与浓度呈正比,在培养35 d时T1处理的土壤蔗糖酶活性已恢复至CK水平,而高浓度处理下的抑制作用则较强。而对于土壤脲酶,高效氟吡甲禾灵反而显著刺激了其活性,除在培养7、21 d和28 d时,T5处理的脲酶活性与CK持平外,随着高效氟吡甲禾灵浓度的增加,土壤脲酶活性逐渐增强。在培养14 d时高效氟吡甲禾灵显著抑制了土壤过氧化氢酶和碱性磷酸酶的活性,在培养7 d时浓度达到T3才开始抑制这两种酶的活性,而在培养21 d时浓度达到T4才开始抑制过氧化氢酶的活性,碱性磷酸酶活性则在浓度达到T3时又恢复到CK水平。研究表明,高浓度高效氟吡甲禾灵条件下,蔗糖酶和脲酶活性被显著抑制和激活,能够表征高效氟吡甲禾灵的污染程度,而过氧化氢酶和碱性磷酸酶在培养21 d时基本恢复到对照水平,表现出较强的耐受性。

To evaluate the toxicological effects of haloxyfop-R-methyl on soil microbial ecosystem,a laboratory incubation experiment was conducted to investigate the responses of soil microbial respiration and enzymatic activities to haloxyfop-R-methyl.Six treatments were included:(1)control(CK);(2)0.01 mg·kg^(-1)(T1);(3)0.04 mg·kg^(-1)(T2);(4)0.08 mg·kg^(-1)(T3);(5)0.16 mg·kg^(-1)(T4);and(6)0.40 mg·kg^(-1)(T5).Results showed that soil microbial respiration was significantly enhanced by T1 treatment during the experimental process.However,T2 and T3 treatments significantly inhibited soil microbial respiration on the 7th and 14th day of culture.Soil microbial respiration in T4 treatment was first inhibited on the 7th day,and then activated,while soil microbial respiration in T5 treatment was basically consistent with that in the control within the first 14 days of incubation.Sucrase activity was significantly inhibited by haloxyfop-R-methyl and significantly and negatively correlated with the concentration of haloxyfop-R-methyl.Sucrase activity in T1 treatment returned to that in the control level on the 35th day;however,the inhibition effect was stronger under the condition of higher haloxyfop-Rmethyl concentration.Soil urease activity was significantly activated by haloxyfop-R-methyl.Soil urease activity was gradually enhanced by increasing the concentration of haloxyfop-R-methyl except in T5 treatment,which soil urease activity was similar to that in the control group on the 7th,21st,and 28th day.The activities of soil catalase and alkaline phosphatase were significantly inhibited on the 14th day of incubation;however,the activities of the two enzymes were initially inhibited at T3 concentration of haloxyfop-R-methyl on the 7th day.Catalase activity was inhibited only when the concentration of haloxyfop-R-methyl reached that of T4,and alkaline phosphatase activity returned to that in the control level when the concentration reached that of T3 on the 21st day.Therefore,sucrase and urease activities were significantly inhibited and activated,respectively under the condition of high haloxyfop-R-methyl concentration,characterizing the pollution degree of haloxyfop-R-methyl.Moreover,the activities of soil catalase and alkaline phosphatase basically recovered to that of the control level on the 21st day,showing strong tolerance to the presence of haloxyfop-R-methyl.