莠去津对土壤过氧化氢酶活性的影响研究

研究了除草剂莠去津对土壤过氧化氢酶活性的影响。试验结果表明,莠去津浓度不同对土壤过氧化氢酶活性影响会不同,随着浓度的升高,对过氧化氢酶活性激活作用有所增强,莠去津对离体过氧化氢酶有一定的激活;336nm处的相对荧光强度不断减弱,酶分子的构象发生了变化．过氧化氢酶分子渐趋紧密。莠去津对过氧化氢酶荧光的猝灭作用主要是由于静态猝灭引起的。     

四溴双酚A对土壤酶活性的影响

采用室内模拟试验方法,研究了四溴双酚A对土壤多酚氧化酶、过氧化氢酶和脱氢酶活性的影响.结果表明,四溴双酚A对土壤多酚氧化酶和过氧化氢酶有一定的激活效应,这可能是土壤微生物在受到外源四溴双酚A胁迫时产生了应激反应,通过增加多酚氧化酶和过氧化氢酶的产生量来降低四溴双酚A及其代谢、中间产物对其产生的危害;同时,四溴双酚A对土壤脱氢酶产生一定的抑制效应,表明其对土壤微生物活性具有一定的抑制作用,但在试验设置的四溴双酚A浓度范围内基本未达到显著水平(P>0.05).     

Cd、Ni单一及复合污染对土壤酶活性的影响

采用外源添加重金属和露天盆栽实验研究了Cd、Ni对含羞草、三叶草根际土壤脲酶、过氧化氢酶和蔗糖酶活性的影响。结果表明,Cd、Ni单一污染条件下,低浓度的Cd、Ni对含羞草组、三叶草组的脲酶、过氧化氢酶有激活作用,高浓度的Cd、Ni对土壤脲酶、过氧化氢酶有一定的抑制作用;对蔗糖酶有较强的抑制作用。在Cd、Ni复合污染条件下,对含羞草组、三叶草组的脲酶、过氧化氢酶和蔗糖酶产生抑制作用;Cd、Ni单一及复合污染对土壤酶活性的抑制大小顺序为:脲酶>蔗糖酶>过氧化氢酶,其中土壤脲酶可以作为Cd、Ni污染的预警指标。含羞草能显著提高土壤脲酶、过氧化氢酶和蔗糖酶的活性,修复能力大于三叶草,在Cd、Ni污染修复方面有很好的应用前景。     

石油污染土壤中漆酶活性的影响因素

针对纯化酶生产成本较高且土壤中漆酶活性较低的问题,通过20 d的室内对照实验,采用ABTS分光光度法测定漆酶活性,研究Cu2+、pH、温度、碳氮比及含水率对漆酶活性的影响,结果表明5个环境因素的最优值分别是40 mg·kg-1、5.2、30 ℃、40∶1和20%。环境因素与漆酶活性的高低有关,其相关性从大到小依次为pH、温度、含水率、碳氮比和铜离子浓度。其中,pH的相关性最高,相关系数为0.956。在最优条件下,培养30 d后石油烃降解率从自然条件下的8.54%提高到18.79%,最高漆酶活性达到13.97 U·g-1。     

等温微量量热法研究石油污染对土壤微生物活性的影响

利用TAMⅢ等温微量量热仪研究不同浓度的石油污染对土壤微生物活性的影响。对大港油田不同石油污染程度的土壤样品（3683-5-1、西51-5、西15-14和8-13-6H-1）以及实验室配置的短时间内石油污染土壤（空白、0.5%、1.5%、2.5%和4.0%）进行了微量热检测。含油量升高,总放热量升高,生长速率常数降低,峰值功率先升高后降低,达到最大峰值功率的时间随着含油量的升高而延长。结果表明,石油污染会影响土壤微生物的活性,并且在低浓度时促进微生物的生长,石油浓度高时会抑制土壤中微生物的生长代谢。     

桉树人工林地土壤养分和重金属现状分析与评价

为了评价大面积人工种植桉树对当地土壤养分变化和重金属富集效应的影响,本研究以普洱市3.75万hm²桉树人工林为研究对象,通过定位观测并将其与当地次生林、撂荒地进行比较,分析土壤养分变化情况、重金属污染等级以及两者之间的相关性。结果表明,桉树林表层土壤养分的含量均高于背景值,其中有效磷、水解性氮、全磷、全钾、有机质和速效钾极显著高于撂荒地（P<0.01）,全氮略高但差异不显著;与次生林相比,桉树林土壤养分全氮和水解性氮显著低（P<0.05）,全钾和全磷的含量显著高（P<0.05）,有效磷的含量极显著高（P<0.01）,有机质和速效钾略高但差异不显著。桉树林表层土壤样品重金属综合污染指数为1.08,低于撂荒地的1.14而高于次生林的0.67,说明桉树林土壤已处于轻微度污染等级,有可能会引起农作物污染,其中铅、锌、铜、镍、砷和铬等6种重金属含量处于安全水平,而镉的单因子污染指数值介于1~2之间,表明桉树林土壤属于轻度镉污染,但相关性分析结果表明,桉树林表层土壤养分的含量与重金属的含量无显著相关。     

不同土地利用方式下土壤养分和重金属元素垂直分布特征

为探讨不同土地利用方式下土壤养分和重金属元素垂直分布特征,对2种母质的自然土壤、耕作土壤、休耕土壤养分和重金属元素垂直分布状况进行了比较研究。结果表明：不同土地利用方式下土壤表层养分元素含量总体表现为休耕土壤＞耕作土壤＞自然土壤,土壤表层重金属含量总体表现为农田土壤（耕作土壤和休耕土壤）＞自然土壤,耕作土壤与休耕土壤差异较小,土壤淀积层到母质层养分和重金属元素差异逐渐减小;土壤养分元素和Cu、Zn、Pb、Cd随土层深度的增加而减小,而Cr表现出相反的趋势;农田土壤耕作层有效钾含量最高可达215.6 mg·kg-1;耕作层Cd含量最高可达0.74 mg·kg-1。3种土地利用方式中,休耕土壤养分和重金属含量相对较高,建议在休耕期间种植伴矿景天等重金属高积累植物进行植物修复。     

采煤沉陷区耕地土壤微生物数量及酶活性的空间特征

通过野外调查和采样分析,研究了焦作矿区韩王矿沉陷区不同沉陷部位和不同深度耕地的土壤微生物数量及酶活性特征。研究结果表明:与对照区比较,沉陷区耕地土壤微生物数量、酶活性赋存特征及微生物类群组成比例发生了明显变化。沉陷区表层(0~5 cm)、上层(5~10 cm)、中层(10~20 cm)土壤微生物总数、细菌数量均明显减少,而下层(20~40 cm)土壤微生物总数、细菌、真菌、放线菌数量均明显升高。沉陷区表层、上层土壤细菌数量所占微生物总数比例分别降低了20.64%和13.17%,而放线菌数量所占比例分别升高了20.69%和12.66%。沉陷区表层土壤脲酶、蔗糖酶、磷酸酶、脱氢酶、过氧化氢酶和多酚氧化酶活性分别降低了1.5%、17.5%、22.0%、35.3%、20.4%和5.4%。不同沉陷部位的土壤微生物数量及部分酶活性指标空间异质性显著(p0.05)。沉陷区土壤真菌、放线菌数量、蔗糖酶、磷酸酶、脱氢酶、过氧化氢酶、多酚氧化酶活性较对照区均具有不同的垂向分布特征。表明采煤引发的地表沉陷使耕地土壤微生物数量及酶活性在水平和垂直方向上均发生了显著变化,而这些变化是导致沉陷区耕地退化、生产力降低的重要原因。     

重金属离子Cd^2＋、Pb^2＋污染对土壤酶活性的影响

通过对土壤中比较重要的两种酶（过氧化氢酶、脲酶）活性的测定,研究了重金属离子（Cd^2＋、Pb^2＋）单因素污染、复合污染对两种酶活性的影响,进而找出重金属污染程度与土壤酶活性的关系,为建立土壤中的酶活性可以表征重金属污染程度的生化指标平台提供试验依据。结果表明,在Cd^2＋、Pb^2＋单因素污染影响中,在一定浓度下的重金属离子对土壤酶活性会有激活效应,但大多表现为抑制效应;Cd^2＋、Pb^2＋复合污染对两种土壤酶活性的影响存在着明显差异,其复合污染对脲酶表现出协同抑制负效应的特征;对过氧化氢酶表现出一定的屏蔽作用。通过重金属离子形态对土壤酶有效性影响的研究,脲酶活性可以作为土壤重金属离子（Cd^2＋、Pb^2＋）单因素和复合污染程度的主要生化指标。     

吐温80对柴油污染老化土壤的洗脱特征及影响

研究了柴油污染土壤的老化特性及吐温80（Tween 80）修复柴油污染老化土壤的效率和对总油中含有不同基团物质的洗脱特性,进行了一系列不同浓度的Tween 80洗脱柴油污染老化土壤实验,并使用红外分光光度法对洗脱后的土壤和残留液中的总油及各基团浓度进行测定。结果表明,经过1年时间的老化,约53%的柴油从土壤中挥发,土壤中残留的总油中约40.55%为稳定吸附态。随着洗脱液中Tween 80浓度的提高,老化土壤中总油量不断减少,但当Tween 80浓度超过3 000 mg·L-1时土壤中总油含量的减少速率和Tween 80的增溶效率的增加速率显著降低,因此3 000 mg·L-1浓度的Tween 80作为洗脱液性价比最高,其对吸附态总油的洗脱率为20.30%,对老化土中总油的洗脱率为67.68%。Tween 80溶液洗脱石油污染老化土时,对含烷烃（CH3）基团和含烯烃（CH2）基团的物质洗脱效率较高,而对于含芳烃（CH）基团的物质洗脱效率相对较低。     

超声波破解对于剩余污泥酶活力的影响

为了研究超声波破解处理对污泥絮体中酶活力的影响,实验利用不同声能密度的超声波对污泥进行破解,并测试酶活力的变化。实验发现,在声能密度为0.48 kW/L和0.96 kW/L下,随着超声破解时间的增长,酶的活力变化总体呈现上升趋势。在声能密度为1.44 kW/L和1.92 kW/L下,酶活力的变化出现先增高后降低的趋势,α-葡萄糖苷酶和蛋白酶活力分别达到最大值69.91 EU/g VS和9.495 EU/g VS。在0.96 kW/L下,超声作用时间15 min时硝酸盐还原酶出现活力最大值5.361 EU/g VS。     

Effect of four experimental insecticides on enzyme activities and levels of adenosine triphosphate in mineral and organic soils

Abstract

A laboratory study was conducted to determine the effect of four experimental insecticides, DOWCO429X, DPX43898, tefluthrin and trimethacarb, on enzyme activities and levels of adenosine 5'‐triphosphate (ATP) in mineral and organic soils. DOWCO429X decreased urease activity in organic soil after 7 days while a stimulatory effect was observed with most treatments after 14 days. No inhibition on acetylene (C₂H₂) reduction by nitrogenase was evident with any of the insecticides in either soil. With the exception of DOWCO429X and tefluthrin at 7 days in organic soil, none of the insecticide treatments inhibited dehydrogenase activity in either soil. Dehydrogenase activity, measured by formazan formation, was greater in many samples in sandy loam than the control throughout the experiment. No inhibitory effect was observed on amylase activity after 2 or 3 days in sandy soil. A stimulatory effect was apparent in many samples after 2 days in organic soil. All insecticide treatments in sandy soil reduced invertase activity at 2 days. However, none of the experimental insecticides inhibited invertase activity after 3 days. A stimulatory effect in invertase activity was apparent in most cases at 2 days in organic soil and no difference was observed after 3 days. Phosphatase activity in insecticide treated samples was equal to or greater than that of control in sandy soil after 2 h. With the exception of DPX43898, the insecticides depressed phosphatase activity in most organic soil samples. The insecticides did not affect ATP levels in either soil. Results indicated that the chemical treatments at the levels tested did not significantly affect activities of enzymes or level of ATP in both soils.     

低聚木糖作为调理剂对土壤微生物和酶的影响

针对集约化农业过量施入化肥农药等引起的土壤质量退化问题,采用造纸黒液废物提取的低聚木糖作为土壤调理剂。通过室内土壤培养,研究不同低聚木糖施用量(0.01%、0.05%、0.1%和0.2%)对土壤微生物数量和脲酶活性的影响。通过番茄盆栽实验,并设置添加0.1%商品生物有机肥处理作比较,研究不同低聚木糖施用量对土壤微生物量氮磷、脲酶和磷酸酶活性的影响。结果表明,低聚木糖可以提高土壤细菌、放线菌数量、土壤脲酶和磷酸酶活性。低聚木糖也显著增加番茄各生长期土壤微生物量碳和磷含量,其中开花期时低聚木糖的促进作用最为明显。所有剂量处理中,以0.05%的低聚木糖添加量处理效果最为明显,且该处理效果也优于添加0.1%生物有机肥处理。低聚木糖作为土壤调理剂,能显著提高土壤微生物数量和酶活性,改善土壤生态系统,提高土壤质量,在农业上具有广阔的应用前景。     

Effect of some herbicides on activities of microorganisms and enzymes in soil

Abstract

Laboratory tests were conducted with eight herbicides, atrazine, butylate, ethalfluralin, imazethapyr, linuron, metolachlor, metribuzin and trifluralin, applied to a loamy sand at rate of 10 μg/g to determine if these materials caused any serious effects on microbial and enzymatic activities related to soil fertility. Some herbicides showed an effect on bacteria and fungi for the first week of incubation, but, subsequently, the populations returned to levels similar to those obtained in the controls. After several herbicide treatments there appeared to cause a slight depression of nitrification. Sulfur oxidation was better than that obtained with untreated soil in all treatments. Oxygen consumption was increased significantly after 96 hr incubation with atrazine. The soil dehydrogenase and amylase activities were inhibited by ethalfluralin treatment respectively for 1 wk and 1 day, and p‐nitrophenol liberation was inhibited for 2 hrs by all herbicide treatments. Results indicated that the herbicidal treatments at the level tested were not drastic enough to be considered deleterious to soil microbial and enzymatic activities which are important to soil fertility.     

德兴铜矿周边地区土壤酶活性研究

采用逐步多元回归和主成分分析的方法研究了德兴铜矿周边土壤中重金属和土壤酶活性的关系.结果表明:德兴铜矿周边各功能区均受到不同程度的Cu、Cd污染,Pb、Zn未超过《土壤环境质量标准》(GB 15618--1995)二级标准;各功能区土壤酶活性有显著差别,逐步回归分析表明土壤酶活性与Cu、Zn全量、生物可利用态Cu含量有显著线性关系,而与Cd、Pb无明显相关;土壤酶活性和生物可利用态Cu呈负线性关系,而与残渣态Cu有正线性关系.主成分分析显示,土壤酶信息系统的第1、第2主成分可反映酶活性总变异的96.27%,根据第1主成分对功能区酶活性的分类结果与土壤生物可利用态Cu含量的分类结果基本一致,提示土壤酶活性指标可以反映土壤生物可利用态Cu含量.     

Effects of butachlor on microbial populations and enzyme activities in paddy soil

This paper reports the influences of the herbicide butachlor (n-butoxymethlchloro -2', 6'-diethylacetnilide) on microbial populations, respiration, nitrogen fixation and nitrification, and on the activities of dehydrogenase and hydrogen peroxidase in paddy soil. The results showed that the number of actinomycetes declined significantly after the application of butachlor at different concentrations ranging from 5.5 microg g(-1) to 22.0 microg g(-1) dried soil, while that of bacteria and fungi increased. Fungi were easily affected by butachlor compared to the bacteria. The growth of fungi was retarded by butachlor at higher concentrations. Butachlor however, stimulated the growth of anaerobic hydrolytic fermentative bacteria, sulfate-reducing bacteria (SRB) and denitrifying bacteria. The increased concentration of butachlor applied resulted in the higher number of SRB. Butachlor inhibited the growth of hydrogen-producing acetogenic bacteria. The effect of butachlor varied on methane-producing bacteria (MPB) at different concentrations. Butachlor at the concentration of 1.0 microg g(-1) dried soil or less than this concentration accelerated the growth of MPB, while at 22.0 microg g(-1) dried soil showed an inhibition. Butachlor enhanced the activity of dehydrogenase at increasing concentrations. The soil dehydrogenase showed the highest activity on the 16th day after application of 22.0 microg g(-1) dried soil of butachlor. The hydrogen peroxidase could be stimulated by butachlor. The soil respiration was depressed during the period from several days to more than 20 days, depending on concentrations of butachlor applied. Both the nitrogen fixation and nitrification were stimulated in the beginning but reduced greatly afterwards in paddy soil.     

Dissipation of carbendazim and chloramphenicol alone and in combination and their effects on soil fungal:bacterial ratios and soil enzyme activities

The dissipation of carbendazim and chloramphenicol alone and in combination and their effects on soil fungal:bacterial ratios and soil enzyme activities were investigated. The results revealed that carbendazim dissipation was little affected by chloramphenicol, whereas chloramphenicol dissipation was found to be retarded significantly by the presence of carbendazim. The inhibitory effect of carbendazim on the fungal:bacterial ratios was increased by the presence of chloramphenicol, and the inhibitory effect of chloramphenicol on neutral phosphatase was increased by the presence of carbendazim. Carbendazim increased soil catalase and urease activities, but this increase was partially diminished by the presence of chloramphenicol. Little interaction was observed between carbendazim and chloramphenicol with regard to their influence on soil invertase. The results obtained in this study suggest that combinations of fungicides and antibiotics may alter the compounds’ individual behaviors in soil and their effects on soil enzymes.