不同除草剂对水花生根茎再生的控制效果

针对常规化学防除仅可杀除外来入侵恶性杂草水花生地上茎叶,一次防治难以有效控制全年危害的防治难题,采用野外小区试验法测定不同除草剂配方对水花生根茎再生的抑制效果,筛选可有效控制水花生根茎再生的除草剂配方,为水花生的可持续治理提供备选药剂和技术指导。结果表明,药后60 d, 24%氨氯吡啶酸水剂(AS)与41%草甘膦异丙胺盐AS桶混处理对水花生的分枝数防效和鲜重防效均达93%以上,极显著高于对照药剂[24%氨氯吡啶酸AS、41%草甘膦异丙胺盐AS、288 g/L氯氟吡氧乙酸异辛酯乳油(EC)、41%草甘膦异丙胺盐AS+200 g/L氯氟吡氧乙酸EC、46%草铵·草甘膦AS、42%2甲·氯氟吡EC];药后365 d, 24%氨氯吡啶酸AS 108 g a.i./hm²及其以上剂量与41%草甘膦异丙胺盐AS 922.5 g a.i./hm²及其以上剂量桶混处理对水花生的分枝数防效均达50%以上,均极显著高于对照药剂。24%氨氯吡啶酸AS与41%草甘膦异丙胺盐AS桶混处理可有效控制水花生的当年危害,降低第2年的发生基数。     

不同除草剂对空心莲子草的控制作用评价

采用盆栽试验,测定了氯氟吡氧乙酸、草甘膦和五氟磺草胺对不同生育期空心莲子草的控制作用,以株防效、鲜重防效和再生抑制率为指标,评价了不同除草剂对空心莲子草的控制效果。结果表明,药后7 d,氯氟吡氧乙酸、草甘膦和五氟磺草胺对不同生育期空心莲子草的株防效,均低于15%;药后15 d,氯氟吡氧乙酸和草甘膦对不同生育期的空心莲子草的株防效、鲜重防效均达100%,但五氟磺草胺对不同生育期的空心莲子草的株防效较差。药后30 d,氯氟吡氧乙酸和五氟磺草胺对不同生育期空心莲子草的再生抑制作用较强,抑制效果达74%以上;草甘膦对生长后期的再生抑制作用达81.3%。空心莲子草苗期对不同除草剂的反应最为敏感。氯氟吡氧乙酸可以作为水生环境和旱生环境下防除空心莲子草的重点药剂,草甘膦可用于旱地空心莲子草的防除,五氟磺草胺可作为水生环境条件下防除空心莲子草的主要药剂之一。     

一种防除林地杂草的混配除草剂田间药效评价

以40%唑草酮WDG、200 g/L氯氟吡氧乙酸异辛酯EC和30%草甘膦AS为对照药剂,进行复配药剂66%氯·唑·草甘膦WP防治林地杂草田间药效试验。结果表明:66%氯·唑·草甘膦WP对林地杂草有良好的防治效果,极显著优于对照药剂。建议使用剂量为1 350 g a.i./ha。66%氯·唑·草甘膦WP安全性好、防效较高、持效期较长,可以进一步示范推广。     

3个草甘膦复配组合对非耕地杂草的防除效果

采用室内盆栽喷雾法和田间茎叶喷雾法,研究草甘膦的复配应用技术。室内测试结果表明:草甘膦与麦草畏配比为(0.5~512)∶1对旱稗和空心莲子草均表现为相加作用;草甘膦与2甲4氯配比为(2.85~5.24)∶1对旱稗和藜均表现为相加作用;草甘膦与草铵膦配比为(0.90~10.32)∶1对旱稗表现为相加作用,对藜表现为增效作用。田间药效结果表明:药后30 d,35%麦草·草甘膦水剂在1 200~1 500 g/hm2剂量下,总草株防效和鲜质量防效分别为93.16%~97.96%和95.24%~99.42%;36%2甲·草甘膦水剂在1 296~2 592 g/hm2剂量下,对总草株防效和鲜质量防效分别为91.09%~94.77%和90.04%~95.07%;36%草甘膦·草铵膦水剂在1 404~2 808 g/hm2剂量下,总草株防效和鲜质量防效分别为92.30%~97.66%和93.08%~97.65%。3个复配剂均能有效防除非耕地杂草,持效期达30 d以上。草甘膦与除草剂复配具有较好的配伍性,与麦草畏、2甲4氯或草铵膦复配均表现为相加或增效作用,室内复配筛选结果与田间药效结果一致。3个复配剂与单剂相比,既增加了药效又提高了速效性。     

苏门白酒草对草甘膦等除草剂的多抗性检测及防治药剂筛选

苏门白酒草Conyza sumatrensis是中国华南地区常见的阔叶杂草,在果园和非耕地常造成严重危害。本研究采用整株剂量反应法,明确了采自广东省广州市的苏门白酒草疑似抗性种群 (GZ-R) 对草甘膦、百草枯和敌草快的抗性水平,比对了GZ-R种群和采自广东省清远市的敏感对照种群 (QY-S) 的草甘膦靶标酶基因EPSPS2片段的差异,并测定了灭草松、氯氟吡氧乙酸等5种茎叶处理剂对不同叶龄苏门白酒草的室内防除效果。结果表明:GZ-R种群对草甘膦和百草枯分别产生了中等水平和高水平抗性,并已对敌草快产生交互抗性,3种药剂对GZ-R种群的LD₅₀值分别是对QY-S种群LD₅₀值的7.2、72.3和6.6倍;与QY-S种群相比,GZ-R种群的EPSPS2基因106位由脯氨酸突变为苏氨酸。在灭草松、氯氟吡氧乙酸或2甲4氯钠推荐剂量下,于4~5叶期施药,苏门白酒草死亡率均为100%,但于6~7叶期和10~12叶期施药,苏门白酒草死亡率显著下降至44.4%~91.7%;而在草铵膦或苯嘧磺草胺推荐剂量下,不同叶龄期施药苏门白酒草的死亡率均为100%,因此在植株生长早期可使用草铵膦和苯嘧磺草胺防除已对草甘膦和百草枯等除草剂产生抗性的苏门白酒草。     

NBD-Cl柱前衍生-高效液相色谱法测定土壤中草甘膦残留

建立了以4-氯-7-硝基苯并呋喃 (NBD-Cl) 柱前衍生为基础测定土壤中草甘膦残留的高效液相色谱法。土壤样品经0.6 mol/L KOH溶液提取，加入NBD-Cl衍生剂，在0.125 mol/L (pH = 9.0~10.5) 硼酸盐缓冲液介质中、60 ℃水浴条件下反应80 min。以0.02 mol/L V (磷酸氢二钠水溶液) : V (甲醇) = 70 : 30的混合溶液为流动相，经C₁₈反相色谱柱分离后，采用二极管阵列检测器在500 nm波长处进行检测，外标法定量。结果表明:草甘膦在0.01~2.0 mg/L 范围内线性关系良好，相关系数为0.9999，定量限 (LOQ) 为0.02 mg/kg；向空白土壤样品中添加0.02、0.1和10 mg/kg 3个水平的草甘膦标准溶液，平均回收率在82%~93%之间，相对标准偏差 (RSD) 为2.5%~3.9%。该方法简便高效，适用于土壤样品中草甘膦的残留分析。     

玉米油甲酯制备及对高效氯氟氰菊酯水乳剂应用效果的影响

为研制并应用绿色溶剂玉米油甲酯以替代5%高效氯氟氰菊酯水乳剂中芳香烃类溶剂,以酸催化法研究了玉米油甲酯最佳合成工艺,采用浸渍法、液滴干燥法、白金吊环法、激光粒度分布仪测定法和点滴法测定了不同用量玉米油甲酯对5%高效氯氟氰菊酯水乳剂最大稳定持留量、液滴干燥时间、表面张力、粒度分布和生物活性的影响。结果表明:醇油摩尔比12∶1、反应温度65℃、反应时间6 h、催化剂浓硫酸用量为油重6%时,玉米油甲酯收率最大为85%;玉米油甲酯溶剂用量由10%提高至30%,5%高效氯氟氰菊酯水乳剂稀释药液在甘蓝、玉米、油菜叶片上的最大稳定持留量呈增大趋势,最大提高率为158.18%;在甘蓝叶片和石蜡载玻片上的干燥时间分别延长16min和17 min;表面张力降低18.4 m N/m;乳粒中位径保持在1μm左右,跨距略有增大。生物活性测定结果显示玉米油甲酯对甜菜夜蛾4龄幼虫的致死率明显提高。表明玉米油甲酯作为5%高效氯氟氰菊酯水乳剂助溶剂,可以保证水乳剂物理稳定性,且可提高药剂施用效果。     

不同生育期转基因抗草甘膦抗虫棉花对草甘膦的耐受性

为明确转基因抗草甘膦抗虫棉田草甘膦的使用适期,于棉花子叶期、3~4片真叶期和花铃期喷施不同浓度的草甘膦,比较药害发生情况、棉花产量和纤维品质。棉花子叶期、3~4片真叶期和花铃期喷施1 640~9 840 g/hm²(有效成分,下同)草甘膦后,施药初期棉花均表现出一定的药害症状,药后4~8 d药害株率和药害指数达最大值,药后12 d药害症状逐渐减轻或消失。棉花子叶期和3~4片真叶期喷施草甘膦,对棉花产量无显著影响,但棉花花铃期喷施2 460~9 840 g/hm²草甘膦后,棉花产量显著降低,降幅达35.0%~63.3%。3个时期喷施草甘膦均不影响棉花的纤维品质。研究表明,转基因抗草甘膦抗虫棉田草甘膦的使用适期为棉花苗期。     

三氯吡氧乙酸、氯氟吡氧乙酸、2甲4氯和草甘膦对葎草的防除活性比较

本文通过温室整株生物测定法比较研究了三氯吡氧乙酸、氯氟吡氧乙酸、2甲4氯钠和草甘膦异丙胺盐4种常用于水稻、小麦种植区防控大龄阔叶杂草的茎叶处理除草剂对6～8叶期葎草Humulus scandens的防除活性。结果表明,在210 g/hm~2剂量下,三氯吡氧乙酸和氯氟吡氧乙酸可完全杀灭供试葎草植株,在420 g/hm~2剂量下,2甲4氯钠对葎草的鲜重抑制率达到95.25%,而草甘膦异丙胺盐840 g/hm~2剂量处理对葎草的鲜重抑制率仍不足80%。进一步通过Logistic曲线模型分析除草剂对葎草鲜重抑制率达到50%和90%的剂量(GR_(50)和GR_(90)剂量)发现,三氯吡氧乙酸、氯氟吡氧乙酸、2甲4氯钠和草甘膦异丙胺盐相应的GR_(50)分别为58.74、76.96、182.52和272.82 g/hm~2; GR_(90)分别为143.97、202.83、678.27和2 980.11 g/hm~2。结论:对于水稻、小麦种植区葎草危害,优先推荐使用三氯吡氧乙酸防除,其次是氯氟吡氧乙酸;使用2甲4氯防控效果不够理想,使用草甘膦无法有效控制。     

氯嘧磺隆抗体制备的研究

以合成的半抗原与牛血清白蛋白(BSA)的联结物为免疫抗原,获得对氯嘧磺隆高亲合力的兔抗血清,建立了氯嘧磺隆的直接竞争酶联免疫检测方法。抗血清效价为6.4×104,IC50值为10.9 ng/mL,测定的线性范围是0.4 ~295.4 ng/mL。在河水中的添加回收率为87.9% ~115.7%。结构相似的常用磺酰脲类除草剂与氯嘧磺隆抗体的交叉反应率为0.1% ~4.8%。所建立的方法可用于河水中氯嘧磺隆的残留检测。     

微囊化溶剂对吡唑醚菌酯微囊悬浮剂应用性能的影响

利用安全溶剂替代农药制剂中的有毒溶剂符合农业可持续发展的要求，乳油中有害溶剂替代已经颇具成效，而微囊剂型中的溶剂替代也应该引起重视。本文先通过比较油酸甲酯和150# 溶剂油对油相稳定性的影响以确定溶剂的种类和用量，采用界面聚合法分别以油酸甲酯和150#溶剂油为溶剂制备了9%吡唑醚菌酯微囊悬浮剂，之后考察了两种制剂的释放性能、抗光解性能和田间应用效果。结果表明；以油酸甲酯为溶剂，当原药与溶剂质量比为1 : 2时，所得的吡唑醚菌酯微囊为球形，平均粒径为2.92 μm，与以150# 溶剂油为溶剂制备的微囊相比，在快速释放液中，20 min时前者中吡唑醚菌酯的累积释放率为92%，后者仅为50%。在模拟紫外光强度下，在100 min时，以油酸甲酯作溶剂的微囊中吡唑醚菌酯含量比以150#作溶剂的微囊中吡唑醚菌酯的含量高30.59%。田间药效试验结果表明，在施药后32 d，用以油酸甲酯为溶剂制备的9%吡唑醚菌酯微囊悬浮剂处理比以150# 溶剂油为溶剂的微囊悬浮剂处理和250 g/L吡唑醚菌酯乳油处理对花生叶斑病的防效分别高16.59%和29.34%。表明溶剂对农药微囊制剂的稳定性和应用性能均存在影响，应该优化筛选。本研究可为农药微囊制剂的精细化加工提供理论依据。     

Joint action of amino acid biosynthesis-inhibiting herbicides

The joint action of binary mixtures of the amino acid biosynthesis‐inhibiting herbicides glyphosate, glufosinate‐ammonium, metsulfuron‐methyl and imazapyr was assessed in pot experiments applying the Additive Dose Model (ADM). Plants of Sinapis arvensis or S. alba were sprayed with seven doses of the herbicides alone and binary fixed‐ratio mixtures of the four herbicides. In total, 73 binary mixtures were studied in six separate experiments. Mixtures of glyphosate and glufosinate‐ammonium were less phytotoxic than predicted by ADM whether commercial formulations or technical grade products were applied. In contrast, mixtures of glyphosate and metsulfuron‐methyl, glyphosate and imazapyr, glufosinate‐ammonium and metsulfuron‐methyl, glufosinate‐ammonium and imazapyr, and metsulfuron‐methyl and imazapyr either followed ADM or were synergistic. Synergism was observed most frequently for mixtures of glyphosate or glufosinate‐ammonium with metsulfuron‐methyl. Synergism was also more pronounced for commercial formulations of glyphosate and glufosinate‐ammonium than for the corresponding technical grade formulations, implying that synergism was caused by the presence of the formulation constituents of the commercial glyphosate and glufosinate‐ammonium formulations in the spray solution.     

70%苯嘧磺草胺WDG防除免耕地杂草效果及对后茬安全性

70%苯嘧磺草胺WDG与41%草甘膦AS混用,速效性较好,持效期较长,对未出土的杂草有一定封闭作用;70%苯嘧磺草胺WDG 21～42 a.i.g/hm2＋41%草甘膦AS 1 230 a.i.g/hm2在免耕地除草后,对后茬直播油菜有一定影响,应进一步试验验证,但对后茬移栽油菜、直播小麦影响较小,可以示范推广应用。     

气相色谱-氮磷检测器测定草甘膦在土壤和苹果中的残留量

建立了简单、灵敏的土壤及苹果中草甘膦残留量的气相色谱检测方法。土壤样品用2 mol/L 的氨水提取,经三氟乙酸酐(TFAA)和三氟乙醇(TFE)衍生化后,由配有氮磷检测器的气 相色谱(GC-NPD)进行检测。土壤中草甘膦的最小检出量为9×10-12 g,最低检出浓度为0.02 mg/kg, 平均回收率及变异系数分别为84.4% ~94.0% 和7.46% ~10.40%。苹果样品则采用去离子水提取,经二氯甲烷液液分配和BIO-RAD AG 50W-X8阳离子交换柱净化后,再用TEAA和TFE衍生化,最后用GC-NPD检测,其中草甘膦的最小检出量(LOD)和最低检出浓度(LOQ)与土壤样品中的相同,平均回收率及变异系数分别为80.7% ~98.6%和9.3% ~11.8%。草甘膦的衍生化产物通过气相色谱-质谱联用仪(GC-MS)进行了确证。在北京昌平地区进行的消解动态和最终残留试验结果表明,以推荐高剂量(有效浓度)的1.5倍(2 025 g/hm2)施药,草甘膦在土壤中的半衰期为 9.2 d。两年的最终残留试验结果表明,无论是高浓度区(2 025 g/hm2)还是低浓度区(1 350 g/hm2),苹果收获时(距施药75 d),土壤和苹果样品中均未检出草甘膦。     

Applying non-steady-state compartmental analysis to investigate the simultaneous degradation of soluble and sorbed glyphosate (N-(phosphonomethyl)glycine) in four soils

The decomposition behaviour of glyphosate in four Victorian soils was investigated at two temperatures using non-steady-state compartmental analysis. At 25°C, glyphosate degradation was shown numerically to be derived from two different sources where the rate of release from each source behaved in accordance with first-order kinetics. Over the first 40 day period for each of the soils, glyphosate was derived simultaneously from the labile and non-labile phase, whilst after the first 40 days, glyphosate was derived solely from the non-labile phase. At this temperature, the amount of glyphosate partitioned into the labile phase ranged from 24·1 to 34·5%, whilst the amount partitioned into the sorbed, non-labile phase ranged from 67·2 to 74·9%. The half-lives for glyphosate within each phase was calculated and ranged from six to nine days for the labile phase to 222–835 days for the non-labile phase. Glyphosate appeared to be more strongly held in the acidic Rutherglen soil than in the alkaline soils studied, and this was thought to be related to the substantially lower pH and higher Fe content of the acidic soil. At 10°C, glyphosate was shown numerically to be derived from two different sources for two of the soils. However, for the two remaining soils, glyphosate appeared to be derived either from a single phase or from two phases at either the same rate or at differential rates where the rate of release from one phase was sufficiently fast to mask the rate of release from the other. At this temperature, more glyphosate was partitioned into the non-labile phase of the Walpeup and Rutherglen soils than at 25°C. However, the rate of release of glyphosate from this phase increased for the Walpeup soil relative to that at 25°C, but decreased substantially for the Rutherglen soil. This suggests that different mechanisms for the binding of glyphosate into the non-labile phase may exist between soils. © 1998 SCI.     

Glyphosate resistance in common ragweed ( A mbrosia artemisiifolia L.) from Mississippi,USA

Glyphosate is one of the most commonly used broad‐spectrum herbicides over the last 40 years. Due to the widespread adoption of glyphosate‐resistant (GR) crop technology, especially corn, cotton and soybean, several weed species have evolved resistance to this herbicide. Research was conducted to confirm and characterize the magnitude and mechanism of glyphosate resistance in two GR common ragweed ( A mbrosia artemisiifolia L.) biotypes from Mississippi, USA. A glyphosate‐susceptible (GS) biotype was included for comparison. The effective glyphosate dose to reduce the growth of the treated plants by 50% for the GR1, GR2 and GS biotypes was 0.58, 0.46 and 0.11 kg ae ha^?1, respectively, indicating that the level of resistance was five and fourfold that of the GS biotype for GR1 and GR2, respectively. Studies using ¹⁴ C‐glyphosate have not indicated any difference in its absorption between the biotypes, but the GR1 and GR2 biotypes translocated more ¹⁴ C‐glyphosate, compared to the GS biotype. This difference in translocation within resistant biotypes is unique. There was no amino acid substitution at codon 106 that was detected by the 5‐enolpyruvylshikimate‐3‐phosphate synthase gene sequence analysis of the resistant and susceptible biotypes. Therefore, the mechanism of resistance to glyphosate in common ragweed biotypes from Mississippi is not related to a target site mutation or reduced absorption and/or translocation of glyphosate.     

New multiple-herbicide crop resistance and formulation technology to augment the utility of glyphosate

Glyphosate has performed long and well, but now some weed communities are shifting to populations that survive glyphosate, and growers need new weed management technologies to augment glyphosate performance in glyphosate-resistant crops. Unfortunately, most companies are not developing any new selective herbicides with new modes of action to fill this need. Fortunately, companies are developing new herbicide-resistant crop technologies to combine with glyphosate resistance and expand the utility of existing herbicides. One of the first multiple-herbicide-resistant crops will have a molecular stack of a new metabolically based glyphosate resistance mechanism with an active-site-based resistance to a broad spectrum of ALS-inhibiting herbicides. Additionally, new formulation technology called homogeneous blends will be used in conjunction with glyphosate and ALS-resistant crops. This formulation technology satisfies governmental regulations, so that new herbicide mixture offerings with diverse modes of action can be commercialized more rapidly and less expensively. Together, homogeneous blends and multiple-herbicide-resistant crops can offer growers a wider choice of herbicide mixtures at rates and ratios to augment glyphosate and satisfy changing weed management needs.     

分子对接阐明草甘膦与水稻醛酮还原酶(OsALR2)的作用及OsALR2的表达纯化

草甘膦是一种广谱高效的有机磷类除草剂, 因其对水稻等禾本科作物缺乏选择性, 导致其在水稻田中的应用受到限制。杂草中醛酮还原酶(aldo-keto reductase, AKR)具有降解小分子农药草甘膦的功能, 但是水稻响应草甘膦的作用机制未知。本文通过生物信息学分析、分子对接研究草甘膦与其在水稻中的靶标AKR蛋白OsALR2的互作机制。采用TMHMM 2.0和DiANNA 1.1 web server 等在线软件对 OsALR2 蛋白的跨膜特性和二硫键含量等生物学特性进行了分析, 结果表明OsALR2分子量为 35 kD, 等电点为 5.89; OsALR2不是膜蛋白, 但是含有3组二硫键。使用AlphaFold 预测OsALR2 蛋白的三级结构, 并利用Auto Dock Vina将草甘膦与OsALR2进行分子对接, 结果显示, 最低结合能为 -13.4 kcal/mol, 草甘膦与OsALR2的结合主要通过氢键作用。通过Ramachandran图, ERRAT和Verify 3D证明对接获得的三维结构是合理的。进一步通过分子克隆技术构建重组表达载体 pET-32a-OsALR2 并进行原核表达, 结果显示OsALR2主要以包涵体的形式表达, 对包涵体进行变复性后, 蛋白表现出酶活性且蛋白结构有较好的均一性。本文的研究结果助于阐明草甘膦与水稻蛋白互作的分子机制, 为研发抗草甘膦水稻新品种和新型小分子农药提供理论指导。     

Saflufenacil efficacy on horseweed and its interaction with glyphosate

Saflufenacil is a new herbicide on the market and its effectiveness on horseweed, several populations of which have evolved resistance to glyphosate, is not clear. In this research, the effect of adjuvants on the control of horseweed with saflufenacil in the field, the effect of the interaction between glyphosate and saflufenacil on glyphosate‐resistant and glyphosate‐susceptible horseweed and the patterns of uptake and translocation of glyphosate applied alone and in combination with saflufenacil in horseweed were evaluated. The addition of methylated seed oil to saflufenacil provided the best control of horseweed, with crop oil concentrate being intermediate in effect and non‐ionic surfactant ranking as the least‐effective adjuvant. The interaction between glyphosate and saflufenacil was additive with regards to the control of glyposate‐resistant horseweed. The glyphosate‐susceptible horseweed population absorbed 6–13% more ¹⁴C‐glyphosate than the glyphosate‐resistant population. The addition of saflufenacil reduced ¹⁴C‐glyphosate translocation in both the glyphosate‐resistant and the glyphosate‐susceptible horseweed populations by at least 6%; however, due to the exceptional efficacy of saflufenacil, these reductions did not reduce the level of control. Saflufenacil holds great potential as an alternative control option for glyphosate‐resistant horseweed and is a valuable tool in the management of resistant weeds.     

Contamination of internationally traded wheat by herbicide‐resistant Lolium rigidum

As herbicide‐resistant weeds have spread in the agricultural fields of grain‐exporting countries, their seeds could be introduced into other countries as contaminants in imported grain. The spread of resistance genes through seed and pollen can cause significant economic loss. In order to assess the extent of the problem, we investigated the contamination by herbicide‐resistant annual ryegrass (Lolium rigidum) of wheat imported from Western Australia into Japan. Annual ryegrass seeds were recovered from wheat shipments and seed bioassays were conducted to identify resistance to the herbicides that are commonly used in Australia: diclofop‐methyl, sethoxydim, chlorsulfuron, and glyphosate. Nearly 4500 ryegrass seeds were detected in 20 kg of wheat that was imported in both 2006 and 2007. About 35% and 15% of the seeds were resistant to diclofop‐methyl, 5% and 6% were resistant to sethoxydim, and 56% and 60% were resistant to chlorsulfuron in 2006 and 2007, respectively. None was resistant to glyphosate in either year. As the contamination of crops by herbicide‐resistant weeds is probably a common phenomenon, the monitoring of incoming grain shipments is necessary to stem the further spread of herbicide‐resistant weeds into importing countries.