乙草胺与农业环境

介绍了除草剂乙草胺的性质、特征及在环境中的行为。同时指出，做为旱田优良除草剂品种之一的乙草胺在水田应用上有着广阔的前景。     

泥炭在水土保持中的应用

泥炭具有独特的物理化学性质,是天然的土壤改良剂。本文综述将泥炭应用于水土保持治理,在改善水土流失、土壤沙化、土质退化、降低土壤污染等方面的作用和意义,鉴于泥炭所具有的优良特性以及我国水土保持的严峻形势,寻求泥炭在水土保持领域的新发展。     

基于RSEI模型的砒砂岩区生态环境质量演变研究

[目的]探究砒砂岩区生态环境质量状况，为当地生态环境治理工作提供科学依据。[方法]基于GIS和RS技术，利用遥感生态指数RSEI模型，分析砒砂岩区2001—2020年生态环境质量时空演变。[结果](1)基于砒砂岩区4期影像数据提取的遥感生态指数RSEI呈现先下降后上升的趋势，表明生态环境质量在缓慢改善；(2)绿度生态指标与湿度生态指标对砒砂岩区生态环境质量起正向作用，干度生态指标与热度生态指标会起到负面作用，并且绿度生态指标对生态环境质量改善的贡献率更高；(3)在2001—2020年间，生态环境质量改善区域占到研究区总面积的36.79%;生态环境质量恶化区域占15.68%,多为轻度退化。[结论]砒砂岩区2001—2020年间生态环境质量总体呈现出上升趋势，且生态环境质量对人为活动高度敏感，因此在改善生态环境的同时还需融入生态保护理念，做到人与自然和谐共生。     

琼海市主要农产品生产基地土壤环境质量评价

依据国家无公害农产品产地的环境质量标准,对琼海市主要农产品基地的土壤进行了采样监测和评价,为该市发展无公害农产品提供科学依据。结果表明,琼海市主要农产品生产基地的土壤环境质量总体优良,完全满足目前国家所规定的无公害农产品安全生产的要求。     

大同市区主要蔬菜生产基地环境质量评价分级

对山西省大同市区主要蔬菜生产基地进行环境质量评价及其分级结果表明,该区主要蔬菜生产基地环境质量总体优良,完全满足目前国家所规定的无公害蔬菜或绿色食品产地环境质量的要求。     

闽江流域生态环境质量动态变化及其驱动力

[目的]探究闽江流域生态环境质量动态变化的驱动因子及相互作用,为该流域生态环境质量改善和实现人与自然和谐发展提供理论支持。[方法]选用2001—2020年的MODIS系列遥感数据,基于Google Earth Engine(GEE)平台计算闽江流域的遥感生态指数(RSEI),结合趋势分析研究闽江流域生态环境质量的时空变化,最后通过地理探测器探测RSEI的驱动因子。[结果](1)RSEI计算结果中4个生态指标的第一主成分平均贡献率达到69.01%,说明RSEI能够充分反映闽江流域生态环境质量状况。(2)闽江流域生态环境质量良好且向好发展。2001—2020年闽江流域的RSEI均值由0.618上升到0.701,生态环境质量等级优良的面积比例增加了19.16%,流域90.28%的地区生态环境质量有所改善。[结论]闽江流域生态环境质量受多个因子共同影响,其中海拔和夜间灯光对闽江流域生态环境质量解释度较高,是主要的影响因素和驱动力,因子间的相互作用均会加大对生态环境质量的影响。     

水土保持优良植物—小冠花

本文较系统的阐述了小冠花的特征特性、栽培技术和繁殖方法及在水土保持方面的作用。同时还对发展小冠花中存在的问题进行了探讨,并对低毒西辐小冠花的优良特性作了简介。     

谷子抗除草剂基因的发现及其应用

谷子田间除草一直是阻碍谷子产业化发展的主要因素之一。谷子抗除草剂品种的出现,解决了谷子田间除草难的问题,有利于谷子大面积的栽培,使谷子产业化发展成为可能。本文围绕谷子抗除草剂基因的发现、类型和机理以及抗除草剂品种在谷子生产中的应用情况等方面进行阐述,探讨谷子抗除草剂应用对环境的影响,并对谷子抗除草剂研究中存在的问题及应用前景进行了展望。     

基于多源遥感数据的土地整治生态环境质量动态监测

土地整治生态转型是土地整治发展的必然趋势,在项目区尺度进行科学合理、客观直接、长期全面的生态环境质量监测评估具有重要意义。该研究基于多源遥感数据,选取典型土地整治项目,运用主成分分析法构建RSEI(remote sensing ecological index)模型,反演得到湿度、绿度、热度、干度指标以及RSEI指数,实现对项目区整治过程中生态环境质量变化的监测与分析。研究结果表明:1)湿度和绿度指标对项目区生态环境质量具有正向作用,而热度和干度指标起负向作用,且干度指标的影响最大;2)RSEI总均值在整治前、中、后分别为0.652、0.572和0.605;RSEI等级中的优良等级在整治前、中、后所占比例分别为78.73%、39.55%和63.29%;RSEI变差、不变和变好的比例分比为42.55%、46.25%和11.20%;3)项目区生态环境质量呈现"先下降-后上升-整体下降"的态势,表现为"整治期变差-恢复期变好-全过程变差"的总体特征,土地整治对项目区生态环境的扰动具有持续性,区域生态环境恢复与改善存在滞后期,在项目竣工5年后项目区的生态环境质量水平仍低于整治前。     

阿特拉津除草剂对土壤微生物生态特征的影响

采用实验室培养试验研究了阿特拉津除草剂对土壤微生物生态特征的影响。结果表明：阿特拉津除草剂10mg／kg浓度处理释放的CO2与对照无明显差异,根据危害系数法的分级方法,其属于无实际危害级农药;阿特拉津除草剂10mg／kg浓度处理在初始阶段,明显降低土壤微生物生物量碳和微生物生物量氮,随培养时间推移土壤微生物生物量碳和生物量氮有所恢复,随后又有所下降,30d后土壤微生物生物量变化趋于平缓;阿特拉津除草剂对土壤微生物多样性产生一定影响．其影响随培养时间而异。在一定程度上反映出土壤微生物生态特征指标可作为除草剂污染土壤环境质量变异的参考指标。     

重金属、磺酰脲类除草剂的植物基因应答及其交互作用

土壤污染日益成为威胁人类生存的重要问题,而且正呈现出多元化和复杂化的特点。土壤的重金属污染已被重点研究,大量与金属阳离子吸收、分布和解毒相关的通道蛋白、螯合剂以及伴侣蛋白的编码基因被发现和克隆;而土壤的农药污染,特别是磺酰脲类除草剂类污染研究却还主要集中在生理生化水平上。同时,两者复合污染研究更是鲜有报道,总体还处于探索阶段。本文重点将对现阶段重金属与磺酰脲类除草剂单因素的植物基因应答及其复合污染交互作用的研究进展,在基因类型和作用等方面分别进行综合性分析与阐述,并结合环境污染现状和国际研究前沿提出了今后研究的主要方向。     

Behavior of four sulfonylurea herbicides in the presence of hydroxy compounds

The behavior of four sulfonylurea herbicides (metsulfuron methyl, chlorsulfuron, chlorimuron ethyl, and bensulfuron methyl) was studied in the presence of various hydroxy compounds. When dissolved at 30 degrees C in simple primary, secondary, or tertiary alcohols (methanol, ethanol, isopropyl alcohol, and tert-butyl alcohol) and in glycerol or in poly(ethylene glycol), most of these herbicides underwent rapid alcoholysis involving the breakdown of the urea part of the molecule. The corresponding sulfonyl carbamate is recovered in high yields, along with a small amount of sulfonylamide formed in the concomitant hydrolysis. Degradation rate constants and the selectivity of conversion were established. The addition of buffered water (pH 7.0) inhibited the alcoholysis reaction, leaving only hydrolysis, as already observed with concentrated saccharide solutions. In phenol solution, slight herbicide hydrolysis was primarily observed. It appeared that alcoholysis reactions only occurred under very particular conditions when sulfonylurea herbicides are dissolved in pure alcohols, without buffered water. These results led to the conclusion that in soil, similar alcoholysis reactions seem unlikely.     

Transformation kinetics and mechanism of the sulfonylurea herbicides pyrazosulfuron ethyl and halosulfuron methyl in aqueous solutions

Pyrazosulfuron ethyl (PE) and halosulfuron methyl (HM) are two new highly active sulfonylurea herbicides that have been widely used for weed control in a variety of vegetables and other crops. These two herbicides have similar molecular structures, differing only in the substitutions on the pyrazole ring. Chemical hydrolysis is a primary process affecting the environmental fate of sulfonylurea pesticides. The hydrolytic transformation kinetics of PE and HM were investigated as a function of pH and temperature. For both herbicides, the hydrolysis rate was pH-dependent and increased with increasing temperature. The hydrolysis of both sulfonylureas was much faster in acidic or basic media than under neutral conditions. Identification of hydrolytic products by liquid chromatography-mass spectrometry (LC-MS) suggested that both PE and HM were subject to cleavage and contraction of the sulfonylurea bridge. The hydrolysis rate of HM was significantly higher than that of PE in alkaline solutions, despite their structural similarity. A chlorine substitution on HM's pyrazole ring makes HM more susceptible to bridge contraction than PE under basic conditions. The hydrolysis of HM and PE was relatively unaffected by the presence of cyclic oligosaccharides (cyclodextrins), indicating that natural OH-containing organic compounds occurring in aquatic environments may have little impact on the transformation of these sulfonylurea herbicides.     

Hydrolysis of sulfonylurea herbicides in soils and aqueous solutions: a review

Sulfonylureas are a unique group of herbicides used for controlling a range of weeds and some grasses in a variety of crops and vegetables. They have been extremely popular worldwide because of their low mammalian toxicity, low use rate, and unprecedented herbicidal activity. Knowledge about the fate and behavior of sulfonylurea herbicides in the soil-water environment appears to be of utmost importance for agronomic systems and environmental protection. Because these herbicides are applied at a very low rate, and their mobility is greatly affected by the chemicals' anionic nature in alkaline soils, a thorough understanding of their degradation/hydrolysis processes and mechanisms under aqueous and soil systems is important. This review brings together published information on the hydrolysis of several sulfonylureas in aqueous and soil solutions that includes the effects of pH, temperature, functional relationship between pH vs hydrolysis rate constants, and hydrolysis behavior of sulfonylureas in the presence of minerals. In addition, the transformations of sulfonylureas in soil, under laboratory and field experiments, have been discussed in connection with the compounds' varied structural features, i.e., sulfonylueas that are with or without the pyridinic, pyrimidine, and triazinic ring.     

氯磺隆污染对土壤生物量碳氮与总有机碳氮比值的影响

The extent and seriousness of the contamination of soils by pesticides still remain to be determined,In agricultural systems,herbicides are the largest class of pesticides used (Shea,1985),Chlorsulfuron is one of the most important sulfonylurea herbicides with important feature of very high herbicidal activity,which results in extremely low application rates of 10-40g ha^-1(Blair and Martin,1988),The sulfonylurea herbicides can persist in the soil for more than 1 year(Brown,1990),Therefore,there has been considerable interest in the side effects of these chemicals on non-target organisms,including soil microorganisms(Greaves and Malkomes,1980),It ios generally recognized that the microbial biomass is the eye of the needle through which all organic materials that enter the soil must pass(Jenkinson,1988), Changes in the microbial biomass-C(Cmic) can provide an early indication of long-term trends in the total organic-C(Corg) of soils(Carter,1986),The Cmic/Corg ratio has been found useful as an index of changes in soil organic matter resulting from land management changes(Hart et al.1989).Many studies were done on relative effect of heavy metals on the ratio of Cmic/Corg but few studies have laid particular attention to the effect of herbicides on this ratio,The present paper reports on the Cmic/Corg and microbial biomass-N/total N (Nmic/Ntotal)ratios in soil as affected by chlorsulfuron.     

Organic amendments from olive cake as a strategy to modify the degradation of sulfonylurea herbicides in soil

Amending soil with products rich in organic matter, such as raw olive cake or alperujo and its compost and vermicompost, could be a simple bioremediation strategy for soil pollutants such as pesticides. To investigate this hypothesis in relation to sulfonylurea herbicides, these amendments were applied to a Mediterranean agricultural soil at rates 4 times higher than agronomical dosage to stimulate biodegradation of chlorsulfuron, prosulfuron, and bensulfuron, added in a mixture to the soils. Degradation studies were conducted in microbially active and sterile soils to check the importance of biological and chemical degradation of sulfonylurea herbicides in nonamended and amended soil. The addition of alperujo stimulated soil microbial activity, as determined by dehydrogenase activity measurements, but it did not enhance the degradation of the sulfonylurea herbicides. In contrast, compost and vermicompost slightly favored the biological degradation of bensulfuron during the first week of incubation. Chlorsulfuron and prosulfuron were mainly degraded by chemical pathways in all substrates, which is probably due to a competitive or inhibitory phenomenon observed between chlorsulfuron and bensulfuron. The first-order kinetic equation satisfactorily explained the experimental data for chlorsulfuron and prosulfuron; however, a biphasic model, such as that proposed by Hoerl, better predicted the results obtained for bensulfuron.     

基质固相分散萃取-高效液相色谱串联质谱法测定土壤中残留的磺酰脲类除草剂

建立了基质固相分散萃取-高效液相色谱串联质谱法(MSPD-HPLC-MS/MS)测定土壤中3种磺酰脲类除草剂(氯磺隆、甲磺隆、苯磺隆)残留的分析方法。对基于球磨的基质固相分散萃取条件进行了详细优化,最终确定最佳条件为:0.2 g土壤样品、0.8 g HC-C18粉末状分散剂与直径为8 mm的小钢珠一起球磨10 min后,转移至空的玻璃萃取小柱,用10 m L乙腈洗脱,氮气吹干后用甲醇定容至0.6 m L,再经0.22μm的滤膜抽滤后装入自动进样瓶中。用Syncronis C18反相色谱柱分离,以甲醇(A)~1‰甲酸溶液(B)为流动相进行梯度洗脱,选择反应监测(SRM)模式下进行检测。氯磺隆在20~200μg·kg~(-1),甲磺隆和苯磺隆在10~200μg·kg~(-1)范围内线性良好,相关系数r在0.997 9~0.999 5。土壤样品的平均加标回收率在84.7%~104.6%,相对标准偏差在4.5%~7.9%(n=5)。方法的检出限(S/N=3)0.32~0.68μg·kg~(-1)。该方法简单、效率高、干扰少、回收率高,满足土壤中除草剂的残留分析要求。     

Effects of organic amendment and herbicide treatment on soil microbial biomass

 The interactive effects of vermi-compost from sewage sludge and either the sulfonylurea herbicide, rimsulfuron, or the imidazolinone herbicide, imazethapyr, on some soil biochemical and microbiological properties were investigated. The herbicides were applied at field and 10-fold field rates. Both herbicides exerted a detrimental effect on soil microbial biomass and its biochemical properties. Even though the effect of both herbicides on soil microbial biomass was not detectable at the field rate, some significant influences on acid and alkaline phosphatase were observed. The higher rate of herbicide application impaired the observed microbial parameters to a greater degree. The detrimental effects seemed to be reduced by organic amendments. Among the studied microbial characteristics, the specific respiration quotient was particularly reliable and sensitive in determining the influence of herbicides on the soil microbial biomass. In this paper a new synthetic index, specific hydrolytic activity (qFDA), for assessing microbial activity in reply to xenobiotic treatments is proposed. Received: 31 May 1999     

水稻对水稻土中甲磺隆结合残留的响应

Metsulfuron-methyl is one of the widely used sulfonylurea herbicides. However, approximately half of the applied metsulfuron-methyl may remain as bound residues in soil. To characterize the response of rice plants to residual metsulfuron-methyl in soil, the activities of acetolactate synthase （ALS）, superoxide dismutase （SOD）, peroxidase （POD）, and catalase （CAT） were investigated in two rice varieties that differed in susceptibility to the herbicide. Changes in the activity of these enzymes in leaves and roots of Xiushui 63, a sensitive rice variety, were greater than those in a resistant variety Zhenong 952. Irrespective of variety, changes in the enzyme activity were greater in the roots than in the leaves. The activities of ALS and CAT decreased, while the SOD activity increased with the increase in the amounts of bound residues of metsulfuron-methyl （BRM） in soil. The POD activity increased at the BRM level of 0.025 mg kg^-1, but decreased at the BRM level of 0.05 mg kg^-1. The results showed that the bound residues of sulfonylurea herbicides may affect metabolism of rice plants.     

模拟设计抗药突变型ALS抑制物结构的研究进展

乙酰乳酸合成酶(ALS)是植物体内合成支链氨基酸过程中的关键酶类。生产上对以ALS为单一靶标的磺酰脲类等5大类除草剂的连续广泛使用,使杂草抗药性突变体大规模产生。本文从计算机辅助药物设计(CADD)的角度出发,综述通过同源模建、结构稳定性分析和分子动力学模拟(MDS)等方法,推测替代突变导致ALS构象变化的抗性机理,并根据模拟抑制物与野生和突变型ALS结合物理参数的差异,如构象标准差、旋转半径、结合自由能,设计理论上对突变型ALS有抑制作用的化合物新结构,以期为抗药突变型靶标与其抑制剂之间的分子作用机理研究和反抗类除草剂的开发提供参考。