乙烯利对草甘膦在空心莲子草中传导及生物活性的影响

在人工气候室培养空心莲子草,植株经草甘膦与乙烯利混合处理后,测定对植株的抑制作用和草甘膦的吸收与传导量.结果表明,加入乙烯利(100 mg*L-1)后草甘膦(300mg*L-1)对地下根茎抑制率比对照提高了13.6个百分点.植株经乙烯利喷雾处理后,基芽、地下茎和根系中14C-草甘膦含量分别是对照的3.56、1.75和2.35倍.放射性成像图显示,植株地下茎与根系中14C-草甘膦传导量明显高于对照.     

赤霉素缓解Mn~(2+)对草甘膦拮抗效应的研究

为探索能够减轻或消除Mn2+对草甘膦拮抗效应的方法,以高羊茅为试材,将赤霉素(GA3)与草甘膦和硫酸锰(Mn2+质量分数为0.1%)混用,研究了赤霉素对Mn2+降低草甘膦药效的缓解作用。结果表明:赤霉素+草甘膦+硫酸锰处理组高羊茅比同剂量草甘膦+硫酸锰处理组叶色更黄,萎蔫更严重,与同剂量草甘膦单剂处理组比较接近,其中加入50 mg/L赤霉素处理组缓解草甘膦拮抗效应的效果最好。赤霉素+草甘膦+硫酸锰处理组高羊茅的干、鲜重及叶绿素含量均低于草甘膦+硫酸锰处理组,而丙二醛和莽草酸含量均明显高于草甘膦+硫酸锰处理组。处理后第6天,赤霉素+草甘膦+硫酸锰组莽草酸含量分别比草甘膦+硫酸锰组增加了49.8%(加入50 mg/L赤霉素)和28.8%(加入30 mg/L赤霉素),差异显著;处理后第2天,赤霉素+草甘膦+硫酸锰组丙二醛含量分别比草甘膦+硫酸锰组增加了54.1%(加入50 mg/L赤霉素)和52.9%(加入30 mg/L赤霉素),差异显著。研究表明,将赤霉素与锰肥和草甘膦混合喷施,将有可能在一定程度上缓解Mn2+对草甘膦的拮抗效应,保证草甘膦的除草效果。     

高锰胁迫下草甘膦对空心莲子草体内莽草酸含量和抗氧化酶活性的影响

鉴于高锰胁迫下空心莲子草Alternanthera philoxeroides对草甘膦的耐药性增强,在水培条件下研究了不同浓度锰条件下草甘膦处理后该草体内莽草酸的积累和主要抗氧化酶系统的响应。次高浓度锰(0.31 mmol/L)条件下培养120 d后空心莲子草体内过氧化氢酶(CAT)活性显著高于常规浓度锰处理(0.009 1 mmol/L,对照);高浓度锰(2.45 mmol/L)条件下超氧化物歧化酶(SOD)活性升高,CAT活性下降。草甘膦(按草甘膦酸68 g/hm2)茎叶处理后6 d内,常规锰浓度培养的空心莲子草体内莽草酸含量比用草甘膦刚处理时增加了31.9％~226.0%,且显著高于同一时间次高锰和高锰的处理;不同锰浓度下培养的空心莲子草体内过氧化物酶(POD)和CAT、SOD活性均为先升高后再逐渐下降,但次高锰处理的该3种酶活性均高于对照,高锰处理的SOD和POD活性高于对照,而CAT活性与对照相当。上述结果表明,在较高锰浓度下空心莲子草能启动抗氧化酶系统而能有效地清除自由基;在草甘膦处理后初期,高锰条件下空心莲子草体内莽草酸途径受抑制程度较轻,抗氧化酶活性较高,这可能是空心莲子草耐高锰和高锰条件下该草耐草甘膦的部分机制。     

有机硅喷雾助剂对草甘膦在空心莲子草上的沉积和生物活性的影响

研究了有机硅喷雾助剂(OSA)对草甘膦在空心莲子草Alternanthera philoxeroides上的沉 积与生物活性的影响。当采用较大喷雾雾滴,施药液量高于632.5 L/hm2时,添加OSA(0.35 g/L) 后,草甘膦药液在空心莲子草上的沉积量显著下降。最大稳定持留量(MRG)由未添加OSA的0.61~0.63 μ L/cm2下降到0.50~0.54 μ L/cm2。分别以33.7和67.4 μ g/株剂量的草甘膦点叶处理空心莲子草,发现添加OSA的处理对再生植株茎叶生长的抑制率分别比对照提高了8.89%和14.83%。草甘膦(有效成分199.3 g/hm2)施药后1 h进行人工模拟降雨处理,添加OSA后药剂对空心莲子草的生物活性比无OSA对照处理提高了20.5%。研究结果表明,添加有机硅喷雾助剂促进了草甘膦在空心莲子草中的向下传导性能,提高了草甘膦水剂在空心莲子草叶片的耐雨水冲刷性能,但会降低草甘膦药液在空心莲子草上的最大稳定持留量。     

草甘膦铵盐对3种滩涂动物抗氧化酶、丙二醛及大弹涂鱼红细胞微核的影响

为评价草甘膦对河口及滩涂水域生物的影响,采用室内人工染毒法,研究了草甘膦铵盐对可口革囊星虫Phascolosoma esculenta、缢蛏Sinonovacula constricta Lamark和大弹涂鱼Boleophthalmus pectinirostris 3种滩涂动物超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)、丙二醛 (MDA) 及大弹涂鱼红细胞微核的影响。结果表明:经低浓度 (63.5 mg/L) 草甘膦短时间 (2 d) 染毒后,可口革囊星虫肠组织的SOD、CAT活性值及MDA含量分别为231.54、1.719 U/mg pro. 和0.60 nmol/mg pro.,3种指标均显著或极显著高于相应对照值 (204.88、1.521 U/mg pro. 和0.54 nmol/mg pro.),且随着药剂处理浓度增加,SOD、CAT活性及MDA含量均升高;但当染毒时间延长至8 d时,可口革囊星虫肠组织的SOD、CAT活性值及MDA含量均明显降低,分别为155.67、1.403 U/mg pro. 和0.53 nmol/mg pro.,显著低于对照,且随药剂处理浓度进一步增加,酶活性及MDA含量值降低更显著。草甘膦对缢蛏内脏团及大弹涂鱼肝脏SOD、CAT活性及MDA含量的影响表现出类似规律。此外,经低浓度 (53.5 mg/L) 草甘膦染毒8 d后,大弹涂鱼红细胞微核率及核异常率分别为17.00‰ 和21.33‰,均极显著高于相应对照值 (13.67‰ 和13.33‰),且随着草甘膦浓度增大,其红细胞微核率及核异常率均显著升高,表明大弹涂鱼对草甘膦有较高的敏感性。所得研究结果可为评价草甘膦对河口及滩涂水域生物的影响提供参考依据。     

36%噻虫啉水分散粒剂对番茄幼苗根系活力及生理生化指标的影响

为明确土壤中施用噻虫啉对番茄植株生长的影响,分别用36%噻虫啉水分散粒剂有效成分1.0、1.5、2.0、2.5、3.0和5.0 mg/株处理盆栽番茄植株,测定处理后30 d番茄幼苗的生长量、叶片保护酶活性及根系活力。结果表明:1.0~2.5 mg/株噻虫啉处理均可提高番茄幼苗展开叶片数、株高、主根长和鲜重等生理指标,3.0 mg/株处理与对照相比无显著差异,而5.0 mg/株处理则对番茄幼苗生长有显著的抑制作用。不同剂量的噻虫啉处理均可提高番茄幼苗叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)和多酚氧化酶(PPO)的活性及根系活力。PPO和SOD活性在2.0 mg/株噻虫啉处理时达到最大值,分别为47.9和14.2 U/(min·g FW),比对照高29.6%和49.5%;POD、CAT和PAL活性在2.5 mg/株剂量时达到最大值,分别为46.0、62.4和26.0 U/(min·g FW),比对照高47.0%、36.7%和35.3%。1.0~5.0 mg/株噻虫啉处理后番茄幼苗根系活力比对照提高2.7%~33.1%。研究表明,土壤施用适量的噻虫啉可显著促进番茄幼苗植株的生长。     

土壤高锰对空心莲子草生长与草甘膦耐性的影响

研究了空心莲子草Alternanthera philoxeroides在土壤中含高浓度锰(简称高锰)胁迫下的生长特性及对草甘膦的耐性。空心莲子草在锰添加量为8～128 mg/kg的土壤中培养20 d后,分枝数比对照(4.43个/株)增加了22.57％～48.31%, 主茎长度比对照(23.85 cm)增长了16.60％～19.87%,地下根茎数比对照(1.54个/株)增加29.87％～47.40%,全株干重比对照(0.23 g)增加22.45%～27.00%;植株叶面积在锰添加量为32～128 mg/kg范围内也显著高于对照(增加10.53%～11.10%)。用草甘膦(有效成分按草甘膦酸计) 68、102和136 g/hm2分别进行茎叶处理后21 d,锰添加量为128 mg/kg的处理,鲜重抑制率分别比不添加锰处理组下降27.39％、24.57％和30.06％。结果表明,土壤高锰条件下空心莲子草的生长和繁殖能力增强,这可能是土壤酸化背景下空心莲子草蔓延加剧的重要原因。土壤高锰条件下生长的空心莲子草对草甘膦的耐性显著增强,使得该杂草的防控形势更为严峻。     

乙烯利对草甘磷在空心莲子草中传导及生物活性的影响

在人工气候室培养空心莲子草,植株经草甘膦与乙烯利混合处理后,测定对植株的抑制作用和草甘膦的吸收与传导量。结果表明,加入乙烯利(100mg·L~(-1))后草甘膦(300mg·L~(-1))对地下根茎抑制率比对照提高了13.6个百分点。植株经乙烯利喷雾处理后,基芽、地下茎和根系中~(14)C-草甘膦含量分别是对照的3.56、1.75和2.35倍。放射性成像图显示,植株地下茎与根系中~(14)C-草甘膦传导量明显高于对照。     

高效液相色谱柱后衍生法测定农田沟渠水中草甘膦残留

为了准确评价草甘膦在农田沟渠水中使用后其对生态环境的安全性,建立了高效液相色谱(HPLC)-柱后衍生法对农田沟渠水中草甘膦残留量的检测方法。将田间沟渠水样中草甘膦经次氯酸钠和邻苯二甲醛、巯基乙醇衍生化后,采用荧光检测器检测。衍生剂1(5%)次氯酸钠添加量100μL/L;衍生剂2硼酸钾和OPA添加量分别是130g/L和100mg/950mL。草甘膦在0.05～2mg/L范围内线性良好,相关系数为0.999 9。在农田沟渠水中,草甘膦3个添加水平(0.05、0.5、1mg/L)的平均回收率(n=5)为98.2%～104.4%,5次测量的相对标准偏差为2.1%～3.6%,方法检出限为0.05mg/L。该方法灵敏、简便、快速,适合于农田沟渠水中草甘膦残留量的检测。     

溴氰菊酯对麦穗鱼谷胱甘肽S-转移酶(GSTs)的影响

研究了溴氰菊酯不同浓度、不同处理时间对麦穗鱼体内谷胱甘肽S-转移酶(GSTs)活性的影响,同时测定了麦穗鱼不同组织中谷胱甘肽S-转移酶对低浓度溴氰菊酯处理的反应特点。结果表明,处理48 h后,高浓度(0.009 mg/L)组对肝中GSTs活性的抑制率达到43.7％,对鳃中GSTs活性的抑制率达54.3％;而低浓度组(0.001 mg/L)对鳃中GSTs活性有一定的诱导作用。亚致死剂量的溴氰菊酯(3.0×10-4mg/L)处理96 h后,对卵巢的诱导活性最高,其GSTs活性是对照的2.43倍,但对肝、鳃、肾、肠的诱导作用均较低。溴氰菊酯对麦穗鱼不同组织GSTs活性诱导的时间效应和强度不同。     

Surfactant and salt affect glyphosate retention and absorption

The influence of nonylphenoxy surfactants and glyphosate salt formulation on spray retention, phytotoxicity and [¹⁴C]glyphosate uptake was investigated in wheat (Triticum aestivum L). and Kochia scoparia L. The amount of spray retained, and uptake of [¹⁴C]glyphosate increased with increasing hydrophilic-lipophilic balance (HLB) value of surfactants. The volume of spray delivered to the plant treatment area and retained by wheat and K. scoparia plants increased with increasing surfactant HLB values, but this only partly accounted for the higher spray retention. Spray retention by leaves of plants was not affected by calcium chloride, either alone or with ammonium sulphate in the glyphosate spray solution. [¹⁴C]Glyphosate absorption by wheat and K. scoparia was reduced by calcium chloride alone, but not in mixtures with ammonium sulphate, regardless of surfactant. Phytotoxicity and uptake of glyphosate salt formulations for wheat was: isopropylamine > ammonium > sodium > calcium; these results indicate that the surfactant selected is important to maintain glyphosate efficacy and that sodium and calcium cations antagonize glyphosate by forming salts that are absorbed less than commercial isopropylamine formulations.     

Effect of ammonium sulphate and other additives upon the phytotoxicity of glyphosate to Agropyron repens (L.) Beauv

In several pot and field experiments additions of 1–10% w/v ammonium sulphate and/or 0.1–2.5% w/v surfactant increased the phytotoxicity to A. repens of sprays containing 0.2–0.5 kg/ha glyphosate. There were similar results with technical glyphosate-isopropylamine salt and formulated ‘Roundup’. Higher ammonium sulphate concentrations were sometimes antagonistic. Additions of ammonium sulphate without surfactant generally had less effect on phytotoxicity. While several surfactants increased glyphosate activity the order of effectiveness of these products varied according to whether or not ammonium sulphate was also present. When used alone, relatively hydrophilic non-ionic or cationic products had more effect. In mixtures with ammonium sulphate, however more lipophilic surfactants gave superior results. Ammonium sulphate (5%) with a lipophilic cationic surfactant (0.5% Ethomeen C12) enhanced the effects of very low volume controlled-drop applications as well as conventional medium volume sprays. In a field trial 0.25 kg/ha glyphosate applied with those additives in 20 l/ha of spray had as much effect on bud viability as l kg/ha applied conventionally.     

Further studies with additives: Effects of phosphate esters and ammonium salts on the activity of leaf-applied herbicides

The phytotoxicity of glyphosate applied to the leaves of dwarf bean (Phaseolus vulgaris L.) and several woody species was enhanced by mixed butyl acid phosphates (BAP, a technical mixture of dibutyl hydrogen and butyl dihydrogen phosphates) or ammonium sulphate. Tributyl phosphate, or the mixed sodium salts of BAP, similarly increased the activity of aminotriazole. This type of effect did not occur with mixtures of this herbicide and inorganic ammonium salts or the ammonium salts of BAP. Neither phosphate esters nor ammonium salts enhanced the activity of paraquat. Ammonium BAP was more effective than sodium BAP as an activator for leaf-applied picloram or MCPA salts. While phosphate esters and ammonium salts probably have separate modes of action they have similar effects in mixture with many water-soluble herbicides and for many purposes may be regarded as alternative activators. Ammonium salts, particularly ammonium sulphate, have obvious advantages because of their cheapness and low mammalian toxicity.     

类黄酮在草甘膦诱导的苦荞膜脂过氧化中的作用

研究了草甘膦对苦荞类黄酮次生代谢的影响及类黄酮与草甘膦作用下膜脂过氧化伤害的关系，以探讨植物类黄酮代谢的意义及在草甘膦伤害中的作用机制。结果表明，分别用浓度为0．1、0．3、1mmoL／L的草甘膦处理苦荞幼苗，苦荞类黄酮代谢受到明显抑制，处理3天时类黄酮含量比对照分别下降58．1％、65．8％和76．5％。草甘膦处理导致苦荞膜脂过氧化加剧，0．1mmoL／L草甘膦处理使苦荞相对电导率增加275．4％、丙二醛（MDA）含量增加134．1％、超氧自由基O2^-产生速率增加121．7％，且随草甘膦浓度升高而增加幅度加大，说明草甘膦伤害与膜脂过氧化程度有关。0．3mmoL／L草甘膦处理后再用0．1mmoL／L类黄酮物质芦丁处理，电解质外渗下降34．2％，MDA含量下降51．1％，O2^-产生下降33．9％，明显减轻了草甘膦的伤害，这说明草甘膦作用下类黄酮含量的下降与草甘膦对苦荞组织伤害有一定的关系。     

Effect of ammonium sulphate and related salts on the phytotoxicity of dichlorprop and other herbicides used for broadleaved weed control in cereals

In glasshouse experiments, additions of 10–100 g 1^?1 ammonium sulphate enhanced the phytotoxicity to broadleaved weeds and cereals of several water-soluble herbicides applied post-emergence in 75–300 1 ha^?1 with hydraulic nozzles. Studies with dichlorprop potassium salt and chickweed Stellaria media (L.) Vill. examined interactions between ammonium sulphate and environmental, application and formulation factors. Simulated rainfall immediately after spraying greatly reduced dichlorprop activity, whether or not ammonium sulphate was present. However, when there was an interval of 2–24 h between spraying and rainfall, the additive increased phytotoxicity. Surfactants tended to reduce dichlorprop phytotoxicity to Stellaria media, both in the presence and absence of ammonium sulphate. Certain other inorganic salts including sodium sulphate also enhanced phytotoxicity. Applications by rotary atomizer in very low spray volume (15 1 ha^?1, 250–280 μm drops) were less effective than conventional 150 1 ha^?1 applications. When very low volume application was used, addition of ammonium sulphate or nitrate tended to reduce activity further. In the field, ammonium sulphate significantly increased the effects against weeds of a commercial dichlorprop potassium salt formulation applied conventionally in 200 1 ha^?1 spray volume. Neutralized phosphoric acid had a similar effect but a mixture of this additive and ammonium sulphate reduced phytotoxicity. Both additives slightly increased dichlorprop injury to barley.     

Uptake, translocation and phytotoxicity of imazapyr and glyphosate in Imperata cylindrica (L.) Raeuschel: effect of herbicide concentration, position of deposit and two methods of direct contact application

The activity of imazapyr and glyphosate against Imperata cylindrica was studied in field and glasshouse experiments using two methods of direct contact application; a rope-wick wiper and a cloth soaked in herbicide solution. The effect of concentration and position of application on herbicide uptake and translocation was also measured. At the lowest dose of imazapyr (5 mg acid equivalent (a.e.) per plant), phytotoxicity was greater from applications by a rope-wick wiper than by a cloth. However, when the dose of imazapyr was increased, the cloth applicator was more effective than the rope-wick wiper. At all doses of glyphosate, rope-wick application was more effective than wiping with a cloth. Herbicide performance in the glasshouse was similar to that in the field. Radiotracer studies showed that increasing the concentration of imazapyr, while keeping herbicide dose constant, decreased uptake and translocation of radiolabel. In contrast, the rate of uptake of ¹⁴C-glyphosate increased with increasing herbicide concentration. Position of application did not significantly affect the amount of uptake and translocation of radiolabel to the rhizomes. It is concluded that rope-wick wipers are more effective than wiping with a cloth for applying imazapyr and glyphosate to I. cylindrica, provided that the concentration of imazapyr does not exceed 10 g a.e. l^?1.     

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。     

Studies on a new group of biodegradable surfactants for glyphosate

The effectiveness of a homologous series of biodegradable rapeseed oil derivatives (triglyceride ethoxylates; Agnique RSO series containing an average of 5, 10, 30 and 60 units of ethylene oxide (EO) as adjuvants for foliage-applied, water-soluble, systemic active ingredients was evaluated employing glyphosate as an example. Previous experiments had revealed that the surfactants used are not phytotoxic at concentrations ranging from 1 to 10 g litre-1. The experiments were performed using Phaseolus vulgaris L and nine selected weed species, grown in a growth chamber at 25/20 (+/- 2) degrees C day/night temperature and 40/70 (+/- 10)% relative humidity. The surfactants were evaluated for enhancement of spray retention, and foliar penetration biological efficacy of glyphosate. Glyphosate was applied at a concentration of 43 mM. The surfactants were added at concentrations of 1 g litre-1. The commercial glyphosate 360 g AE litre-1 SL Roundup Ultra and unformulated glyphosate served as references. The surfactants used improved spray retention, foliar penetration and biological efficacy. Some of the formulations were comparable to the performance of Roundup Ultra in the aspects evaluated; some were even more effective in enhancing spray liquid retention and promoting glyphosate phytotoxicity in several plant species. In these studies Agnique RSO 60 generally was most effective.