叶片倾角、雾滴大小与施药液量对毒死蜱在水稻植株沉积的影响

为提高农药的有效利用率,用丽春红为示踪剂研究了毒死蜱药液在水稻叶片上的沉积特性.随着水稻叶片的倾角变小,毒死蜱的沉积量相应地减少.用体积中径(VMD)为149.5 μm的雾滴处理,在设定叶片倾角为90°、60°、30°时,毒死蜱沉积量分别是直立叶片上沉积量的10.2、5.8、2.9倍.随着叶片倾角变小,雾滴VMD对沉积的影响增大,在90°、60°、30°、0°四个叶片倾角,用VMD149.5 μm雾滴处理的沉积量分别是用VMD 233.7 μm雾滴处理沉积量的1.5、2.1、3.3、5.5倍.在施药液量170～1.36×103L/hm2范围内,毒死蜱沉积量随施药液量的增加而减少.用浓度为800mg/L毒死蜱药液在水稻叶片上测定的最大稳定持留量约为4.66μg/cm2.结果表明,采用小雾滴与低容量喷雾,可显著提高毒死蜱在水稻叶片的沉积量.     

雾滴大小与施药液量对草甘膦在空心莲子草叶片沉积的影响

为提高草甘膦防治空心莲子草Alternanthera philoxeroides时药剂的有效利用率,用丽春红S为示踪剂研究了草甘膦药液在空心莲子草叶片的沉积特性。结果表明,用体积中径(VMD)149.5~233.7 μm的雾滴喷雾,草甘膦在空心莲子草叶片上的沉积量在体积中径为157.3 μm时最多,随着雾滴体积中径增大,沉积量减少。雾滴体积中径157.3 μm与施药液量339 L/hm2处理的沉积量是雾滴体积中径233.4 μm与施药液量694.5 L/hm2处理的1.54倍。施药液量超过382.5 L/hm2时,草甘膦药液的流失明显增多。800 mg/L草甘膦药液在空心莲子草叶片上的最大稳定持留量约为 4.92 μg/cm2。结果表明,喷雾施药时采用小雾滴和较低施药液量,可大幅度提高草甘膦在空心莲子草上的沉积量。     

喷头和施药液量对水稻植株上农药沉积和药剂防治效果的影响

为明确喷头及施药液量对水稻植株上农药沉积及药剂防治效果的影响,采用丽春红-G示踪法测定了4种喷头ST11001、ST11002、TR8001、TR8002在不同施药液量条件下喷雾农药在水稻植株上的沉积分布特性,并比较了4种喷头施用相同剂量的40%氯虫苯甲酰胺·噻虫嗪WDG对水稻纵卷叶螟Cnaphalocrocis medinalis和褐飞虱Nilaparvata lugens的防治效果。结果表明,选择ST11002和TR8001喷头,在施药液量300 L/hm~2条件下喷雾,单株水稻上的丽春红-G沉积量分别达到27.55μg和28.16μg;选择ST11001和TR8002喷头,在施药液量900 L/hm~2条件下喷雾,单株水稻上的丽春红-G沉积量仅分别为12.27μg和14.86μg。喷头和施药液量的改变不影响水稻植株上农药沉积分布特性,均为上层沉积量中层沉积量下层沉积量。当施药液量从300 L/hm~2增加到900 L/hm~2,4种喷头ST11001、ST11002、TR8001、TR8002喷雾在水稻基部的雾滴密度分别增加了8.21、8.54、7.79和9.69倍;但在相同施药液量下,4种喷头在水稻基部的雾滴密度没有显著差异。同一剂量下,喷头和施药液量不同组合的防治效果间差异显著。表明针对稻田不同防治对象,选择合适的喷头及施药液量将有助于提高农药沉积及防治效果。     

氟虫腈在柳州市水稻"两迁"害虫防控上的应用技术研究

试验明确氟虫腈在柳州市水稻"两迁"害虫防治上的最佳用药量、最佳防治适期及与其它农药混配使用的防治技术措施,防治稻飞虱以5%氟虫腈SC每亩40ml、防治稻纵卷叶螟以每亩用5%氟虫腈SC 20ml 20%三唑磷EC 150ml、80%氟虫腈WG 2g 40%乙酰甲胺磷EC 100ml为佳,在大面积推广应用上,总体防治效果达90%以上,具有较好的推广应用前景。     

氟虫腈对水稻害虫的作用特点及应用

通过室内生物测定和田间试验，明确了氟虫腈（商品名为锐劲特Regent）对三化暝的内吸杀虫活性、杀卵活性、持效期和对褐飞虱的杀虫活性以及对水稻主要害虫的田间防治效果，同时评价了其对天敌的安全性。结果表明：（1）氟虫腈由水稻根和茎叶内吸传导对三化暝的杀虫活性高，根和茎叶的内吸对初孵蚁暝的LC50值分别为29．12和13．07mg/L；（2）持效期长，50mg/L氟虫腈药后10d和15d对接三化暝初孵蚁暝的防效仍达92．1％和87．2％，而甲胺磷1000mg/L药后3d的防效即降为0；（3）对三化暝的杀卵效果较差，100mg/L的杀卵效果仅为30．3％，极显著低于500mg/L三唑磷的杀卵效果（95．26％）；（4）对褐飞虱的综合活性高，对3龄若虫的LC50值为10．52mg/L；（5）在江苏高淳、丹阳等地的田间试验表明，5％氟虫腈悬浮剂0．3、0．45、0．75L/hm^2可分别有效控制白背飞虱、三化暝枯心、稻纵卷叶暝、三化暝白穗和褐飞虱；（6）氟虫腈对以狼蛛为代表的稻田蜘蛛杀伤力大，但对暝卵内赤眼蜂幼期较安全。     

毒死蜱·氟虫腈16%乳油防治水稻害虫田间药效试验

试验结果表明,毒死蜱·氟虫腈16%乳油杀虫谱广,是水稻害虫总体防治的理想药剂.毒死蜱·氟虫腈16%乳油100mL/667m2对稻纵卷叶螟的杀虫效果达97.2%,保叶效果达95.9%,显著优于氟虫腈;对二化螟的杀虫效果达95.8%,保穗效果达93.3%,与氟虫腈相当;毒死蜱·氟虫腈16%乳油80mL/667m2,对褐飞虱的防治效果在70%以上,持效期达15d,显著优于氟虫腈.     

氟虫腈在三种土壤中的降解特性研究

实验室条件下,研究了氟虫腈在东北黑土、江西红壤和太湖水稻土中的降解特性。结果表明,氟虫腈在土壤中降解较慢,其在好气条件下的东北黑土、江西红壤和太湖水稻土中的降解半衰期分别为165、267和42 d,在渍水条件下的3种土壤中的降解半衰期分别为31、173和32 d。氟虫腈在pH 偏中性的太湖水稻土中降解最快;微生物对氟虫腈在土壤中的降解起主要作用;渍水条件有利于氟虫腈的降解,推测降解氟虫腈的微生物主要是厌氧菌属。     

喷雾助剂对氟啶虫胺腈在富士苹果叶片表面润湿和持留的影响

为明确喷雾助剂在苹果园化学防治中的作用,采用表面张力、接触角和最大稳定持留量等分析了GY-T12、NF-100和迈润等3种喷雾助剂在达到临界胶束浓度 (CMC) 时对22%氟啶虫胺腈悬浮剂药液的表面张力及其在苹果叶片表面润湿性能和持留量的影响。结果显示:当添加的3种喷雾助剂达到其CMC时,氟啶虫胺腈药液表面张力降低至27.64~35.64 mN/m;根据水滴在苹果叶片表面的接触角小于或大于90°判定苹果叶片近轴面为亲水性表面、远轴面为疏水性表面,添加助剂使药液在近轴面和远轴面30 s的静态接触角分别降低23.2°~41.3°和68.0°~93.5°,同时使亲水性近轴面黏附功降低5.36~12.56 mJ/m2,而黏附张力增大9.27~11.26 mN/m,在疏水性远轴面黏附功与黏附张力分别增大27.45~36.66 mJ/m2和47.55~53.28 mN/m,对改善远轴面的黏附润湿性更显著;药液表面张力和最大稳定持留量存在抛物线状函数关系,当表面张力为40.89 mN/m时,持留量达最大值12.53 mg/cm2;3种助剂中,NF-100和GY- T12可显著增加药液持留量,且GY-T12对靶标害虫苹果黄蚜有显著增效作用。本研究结果表明,在苹果园应用时应依据预期目标选择适当的喷雾助剂,并通过调节药液表面张力使其处于适宜范围以增加药液持留量、提高对靶标害虫的毒力。     

助剂对氯虫苯甲酰胺药液理化性质及在玉米叶片上沉积分布的影响

为选择用于植保无人机作业的喷雾助剂,利用全自动张力仪和接触角测量仪测定添加4种不同喷雾助剂后0.5%氯虫苯甲酰胺药液的表面张力及在玉米叶片上的接触角,应用大疆T20型植保无人机进行田间喷雾,分析添加4种喷雾助剂对玉米冠层不同位置雾滴密度、雾滴覆盖率和雾滴沉积量的影响。结果显示,添加迈飞和Agrospred 910喷雾助剂后,药液的表面张力分别较未添加助剂时显著降低19.6%和30.1%;不同喷雾助剂对药液在玉米叶片上接触角的影响各不相同,添加Agrospred 910助剂后液滴接触叶片60 s后接触角降至11.92°;添加4种喷雾助剂能够有效提高玉米冠层的雾滴密度、雾滴覆盖率和雾滴沉积量,其中添加Agrospred 910助剂后雾滴密度、雾滴覆盖率及雾滴沉积量分别较对照增加了36.93%、35.92%和61.90%。表明在玉米田间使用植保无人机喷雾施药时,可以优选使用Agrospred 910喷雾助剂。     

氟虫腈对家蚕的急性毒性与安全评价研究

氟虫腈是我国稻桑混栽地区水稻上普遍使用的杀虫剂。采用食下毒叶法、口器注入法与药 膜法测定了不同条件下氟虫腈对家蚕的急性毒性。氟虫腈对2龄、3龄、4龄、5龄家蚕的摄入LC50值 (48 h,下同)分别为4.89、6.46、9.47、11.59 mg/L;对5龄家蚕的LD50值为1.38 μg/蚕;在25、30、35 ℃ 3个温度下,氟虫腈对2龄家蚕的LC50值分别为4.81、4.59、2.05 mg/L;桑叶浸药时间为1 s、10 s、1 min、10 min、1 h时,氟虫腈对3龄家蚕的LC50值分别为9.12、6.46、4.39、3.68、2.80 mg/L;家蚕在氟虫腈药膜上爬行1、10、30、60 min后, 对4龄家蚕的接触LC50值分别为2.82、2.35、2.05、1.57 μg/cm2。研究表明,胃毒是氟虫腈对家蚕的主要作用方式,氟虫腈在桑园附近水稻上使用对家蚕有较大风险。     

Biotransformation of clomazone in rice (Oryza sativa) and early watergrass (Echinochloa oryzoides)

Rice (Oryza sativa), a relatively tolerant species, and early watergrass (Echinochloa oryzoides; EWG), a relatively susceptible species, were exposed to ¹⁴C-labeled clomazone to determine accumulation, biotransformation, and mass balance. On a total mass basis, rice absorbed more clomazone than EWG (p < 0.05), but on a nmol/g basis, there was no significant difference between the two species (p > 0.05). Rice contained more extractable ¹⁴C residues (7.7 ± 0.5 vs. 4.8 ± 0.5 nmol in rice vs. EWG, respectively; p < 0.5), but the concentration in EWG was significantly higher (4.2 ± 0.5 vs. 1.8 ± 0.1 nmol/g in EWG vs. rice, respectively; p < 0.01). More metabolized residue was measured in EWG compared to rice (84.1% vs. 67.9%; p < 0.01). Both species produced hydroxylated forms, β-d-glucoside conjugates, and several other unidentified polar metabolites, but EWG generally produced higher metabolite concentrations. The concentration of the suspected active metabolite, 5-ketoclomazone, was significantly higher in EWG vs. rice (21 ± 2 vs. 5.7 ± 0.5 pmol/g, respectively; p < 0.01). Differences in sensitivity to clomazone between rice and EWG appear to be due to differential metabolism, but in this case the more susceptible EWG qualitatively and quantitatively metabolized more clomazone than the more tolerant rice. This is consistent with the action of a metabolically activated herbicide. This metabolic difference could be exploited to develop herbicide safeners for use with clomazone.     

Molecular cloning, expression, and characterization of a phi-type glutathione S-transferase from Oryza sativa

The structural gene for glutathione S-transferase in Oryza sativa was successfully cloned from a cDNA library by the polymerase chain reaction method. The deduced amino acid sequence of this gene showed 44-66% similarity to the sequences of the class phi GSTs from Arabidopsis thaliana and Zea mays. This gene was expressed in Escherichia coli with the pET vector system and the gene product was purified to homogeneity by GSH-Sepharose affinity column chromatography. The expressed OsGSTF3-3 was a homo-dimer composed of 24 kDa subunit and its pI value was approximately 7.3. The OsGSTF3-3 was retained on GSH affinity column and its K_m value for GSH was 0.28 mM. The OsGSTF3-3 displayed high activity toward 1-chloro-2,4-dinitrobenzene, a general GST substrate and also had high activities towards acetanilide herbicides, alachlor, and metolachlor. The OsGSTF3-3 was highly sensitive to inhibition by benastatin A and S-hexyl-GSH. From these results, the expressed OsGSTF3-3 is a phi class GST and seems to play an important role in the conjugation of the chloroacetanilide herbicides.     

Spontaneous ultraweak photon emission from rice (Oryza sativa L.) and paddy weeds treated with a sulfonylurea herbicide

All living organisms spontaneously generate ultraweak photon emissions, which originate from biochemical reactions in cells. Current research uses the ultraweak photon emissions from organisms as a novel tool to investigate the physiological states of plants. In this study, we found ultraweak photon emissions from leaf segments of rice and several paddy weed species treated with a sulfonylurea herbicide. There is a definite difference in photon emissions among plant species, and rice (Oryza sativa), barnyardgrass (Echinochloa crus-galli) and Cyperus serotinus showed extremely strong enhancement of photon emissions. Photon emissions from these three species treated with sulfonylurea herbicide were suppressed when the leaf segments were treated with the cytochrome P450 monooxygenase (P450) inhibitors, piperonyl butoxide and malathion. These results suggest that P450 inhibitors affect the ultraweak photon emissions from plants.     

A plant-specific tau class glutathione S-transferase from Oryza sativa with very high activity against 1-chloro-2,4-dinitrobenzene and chloroacetanilide herbicides

A plant-specific tau class GST gene homolog was successfully cloned from an Oryza sativa cDNA library by PCR using oligonucleotide primers based on the OsGSTU4 (GenBank Accession No. AF309378) sequence. The cDNA was composed of a 720-bp open reading frame encoding 239 amino acids. The deduced amino acid sequence of this gene shared over 65% sequence identity with the sequences of the tau class TaGST28e45 and ZmGST42. Conversely, the OsGSTU4 sequence showed very low identity to the GST sequences of phi, theta and zeta classes. This gene was expressed in Escherichia coli with the pET vector system, and the gene product was purified to homogeneity using GSH-Sepharose affinity column chromatography. The expressed OsGSTU4 formed a homodimer with subunits of approximately 25.5 kDa. OsGSTU4 displayed very high activity toward 1-chloro-2,4-dinitrobenzene. The activity of the OsGSTU4 was significantly inhibited by S-hexylglutathione and hematin. Plant OsGSTU4 had a unique herbicide specificity and played an important role in the detoxification reaction against fluorodifen and chloroacetanilide herbicides.     

三唑磷与氟虫腈复配对粘虫的增效机理研究

以粘虫Mythimna separate 4龄幼虫为试虫,从表皮穿透、生物转化、作用靶标3个方面研究了三唑磷·氟虫腈复配剂的增效机理。结果表明,三唑磷与氟虫腈复配后,相互促进了对方对粘虫表皮的穿透作用;三唑磷对酸性磷酸酯酶(ACPase)的竞争性抑制与氟虫腈对ACPase的非竞争性抑制与反竞争性抑制的混合型抑制相结合,使复配剂对ACPase的抑制能力大幅度提高;对谷胱甘肽S-转移酶(GSTs)的联合抑制系数(JIC)达到425.87,表现出显著的增效作用;三唑磷和氟虫腈对乙酰胆碱酯酶(AChE)只有微弱的交互作用。表皮穿透率的提高及其对ACPase和GSTs抑制能力的增强可能是该复配剂对粘虫增效的重要机理。     

Protective effects of Nigella sativa oil on propoxur-induced toxicity and oxidative stress in rat brain regions

Propoxur (PPr) is a widely used broad spectrum carbamate insecticide mainly used to control household pests. Because of the widespread use of pesticides for domestic and industrial applications, evaluation of their neurotoxic effects is of major concern to public health. The aim of the present study was to evaluate the possible protective effects of Nigella sativa oil (NSO), an antioxidant agent, against PPr-induced toxicity and oxidative stress in different brain regions of rats including cerebellum, cortex and hippocampus. In the present study, 32 male Sprague-Dawley rats were used and divided into four equal groups. Group 1 was allocated as the control group. Groups 2-4 were orally administered 1 ml/kg/bw/day NSO, 8.51 mg/kg/bw/day PPr or NSO plus PPr, respectively, for 30 days. Lipid peroxidation (LPO), protein carbonyl content (PCC) and acetylcholine esterase activity (AChE) were determined. Enzymatic antioxidant activities [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST)] and non-enzymatic antioxidants [reduced glutathione (GSH)] were determined. PPr treatment significantly increased the levels of LPO, PCC and oxidized glutathione (GSSG) in brain regions. On the contrary, levels of GSH and the activities of SOD, CAT, GSH-Px, GST and AChE were significantly decreased. NSO treatment to PPr intoxicated rats restored such biochemical parameters to within control levels except GST activity, emphasizing its antioxidant role. We conclude that NSO significantly reduces PPr-induced toxicity and oxidative stress in rat brain regions via a free radicals scavenging mechanism.     

喷雾助剂及施液量对植保无人机喷雾雾滴在水稻冠层沉积分布的影响

为提高农药沉积率,利用黏度计、表面张力仪、药液润湿性测试卡、激光粒度仪测定不同喷雾助剂添加量对蒸馏水溶液性质的影响,并分析喷雾助剂及施液量对水稻冠层不同位置雾滴沉积密度、沉积量以及有效沉积率的影响。结果表明,添加喷雾助剂对蒸馏水溶液的性质有显著影响,与蒸馏水相比,当添加喷雾助剂为0.5%和1.0%时,雾滴体积中径变为108.9、98.7μm,表面张力降低64.7%、64.9%,黏度增加为2.3、2.3 m Pa·s,铺展系数为蒸馏水的74.5、58.5倍,能有效促进雾滴铺展并避免药液流失;植保无人机喷施试验结果显示,增加施液量可显著提高雾滴沉积密度,添加喷雾助剂可以显著提高雾滴沉积量以及有效沉积率,当施药量为13.5 L/hm~2且添加1.0%喷雾助剂时,雾滴在水稻冠层的有效沉积率最大,为48.9%。     

枣镰翅小卷蛾成虫的寄主趋向和产卵选择

采用固相微萃取(SPME)和GC-MS分析研究木枣和酸枣挥发物成分,并测试枣镰翅小卷蛾触角电位(EAG)反应、寄主趋向和产卵选择,以探明枣镰翅小卷蛾的寄主选择机制。结果显示,在萌芽期,木枣和酸枣嫩叶的挥发成分均为罗勒烯、2-甲基-2-菠烯、α-法呢烯和邻苯二甲酸二丁酯4种,但相对含量稍有不同。枣镰翅小卷蛾成虫对木枣和酸枣2种寄主都有强烈的EAG反应,且同一寄主上雌蛾的EAG反应值极显著地高于雄蛾,其EAG值是雄蛾的3.3倍。枣镰翅小卷蛾对木枣表现强烈的趋向反应,而对酸枣的趋向不明显,且雌虫的趋向反应显著高于雄虫。木枣上的产卵量显著高于酸枣,且木枣枣吊上的单雌产卵量为307.9粒,极显著地高于酸枣枣吊上的产卵量(182.9粒)。研究表明,枣镰翅小卷蛾雌蛾在寄主选择中起主导作用,木枣是其嗜好寄主。