12种除草剂对冬小麦田阔叶杂草的防除效果

为了筛选出对麦田阔叶杂草防效较高的药剂,选择12种目前生产中常用的除草剂进行大田试验。结果表明,施药后15d,对播娘蒿、荠菜、猪殃殃三种杂草总体株数防效最好的是对杂草致死速度快的唑草酮,40%唑草酮水分散粒剂30g(a.i.)·hm-2(指每公顷有效成分用量为30g,其余类推)处理的株数防效达91.78%;施药后30d对三种杂草总体株数防效最好的是55%苯·唑·2甲钠可湿性粉剂412.5g(a.i.)·hm-2处理,株数防效为96.53%,鲜重防效为98.79%;总体株数防效和鲜重防效仅次于55%苯·唑·2甲钠可湿性粉剂处理的分别是58g·L-1双氟·唑嘧胺悬浮剂11.8g(a.i.)·hm-2处理(株数防效为93.59%)、37%炔·苄·唑草酮可湿性粉剂222g(a.i.)·hm-2处理(鲜重防效为98.76%);总体鲜重防效最低的是30%二氯吡啶酸水剂202.5g(a.i.)·hm-2处理(鲜重防效仅为35.29%)。三种杂草对同种药剂的敏感性存在差异。12种除草剂对小麦的安全性有一定差异,唑草酮及其混剂处理后小麦产生的触杀型药害斑及啶磺草胺处理的小麦叶片黄化均可恢复,对小麦的产量无不良影响,其他处理均对小麦安全。     

不同药剂对麦田看麦娘属(Alopecurus)杂草的防除效果

本文比较了异丙隆、炔草酯、甲基二磺隆等不同药剂对小麦田看麦娘属(Alopeeurus)杂草的防除效果。结果表明:3%甲基二磺隆OD 20 mL/667 m~2、5%唑啉草酯EC 80 mL/667 m~2、8%炔草酯EW 60 mL/667 m2和7.5%啶磺草胺WG 15 g/667 m~2均可高效防除冬小麦田看麦娘属杂草;冬前施药50%异丙隆WP 250 g/667 m~2防效明显好于春后施药。建议防除冬小麦田看麦娘属杂草尽量选择冬前施药,药剂可选择50%异丙隆WP单用或与其他不同类型的除草剂混用,用量推荐50%异丙隆WP 150~200 g/667 m~2。     

17种除草剂对小麦田猪殃殃的防除效果

为筛选出对麦田恶性杂草猪殃殃防效较好的药剂,对17种除草剂开展了温室盆栽试验和田间小区试验。温室盆栽试验中,200g·L~(-1)氯氟吡氧乙酸乳油和25%灭草松水剂对猪殃殃有较好的抑制作用,试验剂量下鲜重抑制率均达100.00%。田间小区试验中,对猪殃殃防效最好的是80%唑嘧磺草胺水分散粒剂,用药25.00g(a.i)·hm~(-2)后30d对猪殃殃的株数防效为85.08%,药后60d的株数防效和鲜重防效则达100.00%;其次为50g·L~(-1)双氟磺草胺悬浮剂、200g·L~(-1)氯氟吡氧乙酸乳油。     

三氯吡氧乙酸对小麦的安全性及生物活性评价

三氯吡氧乙酸属人工合成激素类除草剂,具有用量少、活性高、选择性强等优势。为明确其在小麦田的应用技术,采用整株水平生物法测定了其对10个安徽主栽小麦品种的安全性及对阔叶杂草的生物活性。结果显示,三氯吡氧乙酸对多种阔叶杂草具有较好的活性,在供试剂量288 g(a.i.)·hm^-2时,对荠菜、球序卷耳、大巢菜、宝盖草、葎草、猪殃殃、鳢肠、鬼针草、野老鹳、播娘蒿、牛繁缕、小飞蓬、羊蹄、车前草、青葙活性较好,鲜重抑制率达90.39%~100%;在用量72 g(a.i.)·hm^-2时,对葎草鲜重抑制率达100%,对播娘蒿、荠菜、牛繁缕、球序卷耳、大巢菜、小飞蓬、羊蹄、猪殃殃的活性次之,鲜重抑制率在60.44%~84.30%之间;其对阿拉伯婆婆纳、荠菜、播娘蒿、野老鹳的GR₅₀值分别为97.13、43.03、48.58、54.37 g(a.i.)·hm^-2。安全性结果表明,在用量576 g(a.i.)·hm^-2时,对10个供试小麦品种均较安全,株高抑制率和鲜重抑制率分别在2.98%~13.34%和3.29%~17.47%之间。三氯吡氧乙酸在4种供试小麦烟农999、荃麦725、安农0711、淮麦44和杂草阿拉伯婆婆纳、荠菜、播娘蒿、野老鹳草之间的选择性指数在2.39~12.70之间,表明该药剂在供试小麦与杂草间具有良好的选择性。     

水稻直播田抗药性杂草防控技术探讨

田间试验表明,采用"一封一杀"的动态防治模式,以"封闭为主,茎叶喷雾为辅"的防治策略较为符合浙中稻区水稻直播田生产用药实际."一封一杀"是指播后芽前每667 m2用30％丙草胺EC100 mL进行土壤封闭,苗后杂草用300 g/L丙草胺EC100 mL+3％氯氟吡啶酯OD 53.3 mL、13％氰氟·氯氟吡啶酯EC 8...     

河南省3种麦田阔叶杂草对苯磺隆的抗性

为明确河南省冬麦田3种阔叶杂草猪殃殃、播娘蒿、牛繁缕对苯磺隆的抗性水平和分布现状,在温室中采用整株剂量-反应测定法测定了3种杂草的40个种群对苯磺隆的敏感性。结果表明,河南省3种阔叶杂草已普遍对苯磺隆产生抗性,所测样本中,抗性种群27个,占总采样数的67.50%,其中牛繁缕抗性水平最高,猪殃殃居中,播娘蒿最低。豫中和豫南地区3种杂草的整体抗性水平较高,豫西和豫西南抗性水平相对较低。     

播娘蒿对双氟磺草胺的抗性水平及靶标抗性分子机理

为明确麦田杂草播娘蒿对双氟磺草胺的抗性水平及靶标抗性分子机理，采用整株-剂量响应法测定了播娘蒿对双氟磺草胺的抗性水平，通过克隆测序进行了靶标乙酰乳酸合成酶(ALS)基因序列比对分析，并通过测定靶标酶离体活性，分析了抗性和敏感种群播娘蒿ALS对双氟磺草胺的敏感性。结果显示，与敏感种群TS 相比，抗性种群G₁₃₀ 对双氟磺草胺产生了高水平抗性，抗药性指数为108.6；在G₁₃₀种群中随机抽取100株，对其ALS基因进行测序，比对分析发现，33%植株ALS 的第197位脯氨酸突变为苏氨酸，40%植株ALS 的第574位色氨酸突变为亮氨酸，27%植株的ALS 同时存在上述两种突变。ALS 离体活性测定结果表明，双氟磺草胺对抗性种群ALS 的活性抑制中浓度为敏感种群的137.8倍。这说明，播娘蒿抗性种群ALS 关键位点氨基酸的突变可能是导致其对双氟磺草胺产生高水平抗性的重要原因之一。     

啶磺草胺对青稞田旱雀麦的室内和田间防除效果

采用室内和田间测定药效相结合的方法,明确啶磺草胺对青稞田恶性杂草旱雀麦(Bromus tectorum L.)的防除效果及安全性.室内啶磺草胺4.68、9.37、18.74、37.49、74.99μg/m2处理对旱雀麦干质量抑制率分别为18.89％、30.37％、34.52％、37.86％、50.00％,回归方程为Y=23.644+0.551 4X.田间啶磺草胺6.5、12.5、20.0、25.0 g/667 m2不同处理,20 d时对旱雀麦防除株效分别为77.26％、93.70％,97.70％、98.85％;40 d 时防除株效分别为70.25％、92.45％、95.28％、98.78％,鲜质量抑制率分别为75.44％、99.40％、99.12％、99.42％.不同剂量啶磺草胺均对青稞表现安全且无统计学差异.通过室内和田间测定筛选出啶磺草胺适宜剂量为12.5 g/667 m2,增产率达4.29％,对青稞表现安全.     

75%三氟啶磺隆钠盐WG对棉田杂草的防除效果

研究新型除草剂三氟啶磺隆钠盐防治棉田杂草效果及其对棉苗安全性的影响,结果表明:75%三氟啶磺隆钠盐WG22.5～33.75 g.hm-2,对4～5叶期前的棉花较安全。药后15 d、30 d对莎草和禾本科杂草株防效分别达到58.42%～60.63%和75.5%～78.6%,鲜重防效达84.1%～88.4%;11.25～33.75g.hm-2,对凹头苋等阔叶杂草药后15 d和30 d株防效可达到98.03%～99.24%和99.2%～100%,鲜重防效达99.8%～100%;三氟啶磺隆钠盐与精喹禾灵混用可显著提高对莎草的防效。     

不同除草剂对盘锦地区旱直播田杂草防除效果研究

近年来,随着水稻直播方式在辽宁滨海稻区的推广,为解决新的农田杂草防治问题.本研究通过选用4种除草剂进行田间主要杂草株防除试验.试验结果表明,460 g/L二甲·灭草松SL对除稗草外杂草防治效果最好,50％二氯喹啉酸WP对稗草防效最好,25 g/L五氟磺草胺OD和19％氟酮磺草胺SC杀草范围最广,25 g/L五氟磺草胺O...     

油菜菌核病菌对嘧菌环胺和不同杀菌剂敏感性的相关分析

为了明确油菜菌核病菌对新型杀菌剂嘧菌环胺的敏感性和该药剂与其它杀菌剂的交互抗性,采用菌丝生长速率法测定江苏省不同地区的53个油菜菌核病菌菌株对嘧菌环胺的敏感性,并测定对嘧菌环胺不同敏感性的10个菌株对菌核净、异菌脲、腐霉利、多菌灵、咪鲜胺和戊唑醇等杀菌剂的敏感性。结果表明,菌株间对嘧菌环胺的敏感性差异显著, EC50（抑制中浓度）值在0.0342～1.087 6μg/mL之间;通过EC50值相关性分析,油菜菌核病菌对嘧菌环胺与上述杀菌剂之间不存在交互抗性。 关     

浅谈永德芒果产业现状、问题与发展对策

简述云南永德芒果的栽培历史和产业现状,分析了目前芒果产业发展中存在的问题,提出促进产业发展的对策。     

发根农杆菌抑菌剂的抑菌效果及对茶组培苗丛生芽的影响

研究了MS培养基中不同浓度头孢噻肟钠（Cefotaxime sodium）、羧苄青霉素（Carbenicillin）和特美汀（Timentin）3种抑菌剂对发根农杆菌的抑制效果及对茶树组培苗丛生芽的影响。结果显示,头孢噻肟钠和特美汀均可以有效抑制农杆菌LBA9402、15834,而15834在羧苄青霉素的板上17βd内长出;对于外植体,头孢噻肟钠和羧苄青霉素都显著降低了茶组培苗的丛生芽增殖率,且畸形苗率高;当特美汀质量浓度在400βmg·L^-1以下时,对茶组培苗影响较小,与正常对照无显著差异,特美汀具有作为茶树遗传转化体系中抑菌剂的潜力。     

A Microencapsulation Method for Delivering Tetrodotoxin to Bivalves to Investigate Uptake and Accumulation

Most marine biotoxins are produced by microalgae. The neurotoxin tetrodotoxin (TTX) has been reported in many seafood species worldwide but its source is unknown, making accumulation and depuration studies in shellfish difficult. Tetrodotoxin is a water-soluble toxin and cannot be directly ingested by shellfish. In the present study, a method was developed which involved binding TTX to solid particles of humic acid and encapsulating them in agar-gelatin capsules. A controlled quantity of TTX-containing microcapsules (size range 20–280 μm) was fed to Paphies australis, a bivalve known to accumulate TTX in the wild. The TTX-containing microcapsules were fed to P. australis every second day for 13 days. Ten P. australis (including five controls fed non-toxic microalgae) were harvested after 7 days and ten after 13 days. Paphies australis accumulated TTX, reaching concentrations of up to 103 µg kg⁻¹ by day 13, exceeding the European Food Safety Authority recommended concentration of 44 μg kg⁻¹ in shellfish. This novel method will allow future studies to explore the effects, accumulation and depuration rates of TTX in different animals and document how it is transferred through food webs.     

抗氧化酶和植物螯合肽对苎麻重金属Cd胁迫的应答

为了探究抗氧化酶和植物螯合肽在苎麻耐镉生理机制中的作用,本研究以苎麻耐性品种‘川苎8号'为实验材料,对其进行5、25、50 mg/L的镉处理,7 d后分别测定其生物量、镉含量、抗氧化酶活性、植物螯合肽含量以及相关基因表达量。结果表明5 mg/L镉处理‘川苎8号'的株高、根长与生物量受到促进,25、50 mg/L镉处理下‘川苎8号'的株高、根长与生物量受到抑制,‘川苎8号'主要将镉积累在根部,不同镉处理下转运系数均小于1,25 mg/L镉处理时镉积累量与转运系数均显著高于其他处理;镉胁迫后‘川苎8号'地上部和地下部超氧化物歧化酶（SOD）活性显著升高,丙二醛（MAD）活性显著降低,过氧化氢（H₂O₂）含量显著上升;5、25 mg/L镉处理时地下部植物螯合肽（PCs）与谷胱甘肽（GSH）含量显著低于对照,50 mg/L镉处理时高于对照但未达到显著差异;PCs和GSH在地上部和地下部承担着不同的解毒作用;各浓度处理的地上部BnPCS1相对表达量均与镉含量呈极显著正相关（P<0.01）,高浓度（25、50 mg/L）处理的地上部BnGCL1相对表达量与镉含量呈正相关（P<0.01）;低浓度（5 mg/L）处理下SOD活性显著高于对照,与各部位镉含量均呈极显著正相关（P<0.01）,高浓度镉处理时地下部SOD活性与镉含量呈极显著负相关（P<0.01）,地下部PCs含量与镉含量呈极显著正相关（P<0.01）。综合分析说明,‘川苎8号'在低浓度镉胁迫时主要通过激活抗氧化酶活性消除细胞中自由基的毒害,高浓度镉胁迫时通过调节抗氧化酶活性和PCs与GSH合成解除镉的毒害。     

Differential Sensitivity of Rice Cultivars to Salinity and Its Relation to Ion Accumulation and Root Tip Structure

Abstract

Effects of NaCl on the growth, ion content, root cap structure and Casparian band development were examined in four rice (Oryza sativa L.) cultivars with different salt resistance (salt-sensitive indica-type IR 24 and japonica-type Nipponbare and salt-resistant indica-type Nona Bokra and Pokkali). Experiments were conducted to find the differences in salinity resistance during early seedling and developed seedling stages among the cultivars. For salinity treatment, sodium chloride (NaCl) was added to nutrient solution at concentrations of 0, 25 and 50 mM for 7 days from germination to the 7th day (early seedling stage) or from the 7th day to 14th day (developed seedling stage). Growth inhibition by salinity was more prominent in the early seedling stage than in the developed seedling stage. Based on the growth, the order of the sensitivity was IR24 > Nipponbare > Nona Bokra > Pokkali. The growth of NaCl-treated rice cultivars relative to control was significantly and negatively correlated with the Na⁺ content and Na⁺/K⁺ ratio in roots and shoots in both stages. Scanning electron microscopic observation revealed that the root cap tissues proliferated and extended to the basal part of the root tip by salinity. The length of root cap was, however, reduced by 50 mM NaCl in sensitive cultivars due to peeling off. An endodermal Casparian band was formed in the basal region of the root tip. Development of the Casparian band was more prominent in sensitive cultivars than in tolerant cultivars. Root cap proliferation might be related to NaCl resistance in rice seedlings, but the Casparian band may not function efficiently in Na⁺ exclusion. Essentially the present results suggest that exclusion of Na⁺ from roots plays a critical role in expression of Na⁺ resistance in rice seedlings and the root cap is important for Na⁺ exclusion.     

Production and behavioural responses of high- and low-yielding dairy cows to different periods of access to grazing or to a maize silage and soyabean meal diet fed indoors

The study examined whether high‐yielding cows grazing pasture respond differently from low‐yielding cows in milk production and feeding behaviour, to increasing the time made available for eating a maize silage and soyabean meal (TAMS) diet indoors and reducing the time available for grazing (TAG). Two experiments, each lasting 42 d, were carried out in spring (Experiment 1) and autumn (Experiment 2) using Holstein‐Friesian cows at two different levels of milk yield (MYL). Milk production and feeding behaviour were examined for TAG + TAMS systems of 19 h, TAG plus 1 h TAMS (19 + 1), and 5 h TAG plus 15 h TAMS (5 + 15). There were two levels of concentrate (0 and 6 kg d^?1), and in the spring experiment two sward heights (4–6 and 8–10 cm) were also studied. Milk yield, persistency of milk yield, liveweight change and estimated total DM intake were significantly higher on the 5 + 15 than on the 19 + 1 grazing system in Experiment 1 but not in Experiment 2. There were no significant interactions of TAG + TAMS treatment with MYL for any production or behavioural measurements except for maize silage feeding time, where high MYL cows spent a significantly greater time eating maize silage than low MYL cows on the 5 + 15 treatment but not on the 19 + 1 treatment. It can be concluded that high‐ and low‐yielding cows respond similarly in milk production and feeding behaviour to different combinations of TAG and TAMS. In autumn, estimated daily intakes of herbage were lower on both grazing treatments relative to spring, resulting from lower rates of herbage intake with no compensatory increase in grazing time. In contrast, rates of intake of maize silage were higher in autumn especially on the 19 + 1 system. These results may imply a change of preference from herbage to maize silage between spring and autumn.