安徽省棉田马唐对草甘膦的抗药性研究

为明确安徽省不同生态区棉田马唐对草甘膦的抗药性水平,采用培养皿种子检测法、整株植株测定法和症状级别法测定池州市、安庆市、芜湖市、滁州市、蚌埠市、阜阳市等地共9个点马唐对草甘膦的抗药性水平。3种检测方法结果均表明:安徽安庆市大观区海口镇皖河农场马唐相对抗药性倍数最高,抗药性指数分别为3.23、3.52和4.91;培养皿种子检测法和整株植物测定法检测的结果基本一致,而使用症状级别法检测的马唐的相对抗药性倍数略高于其他2种方法。     

棉田反枝苋和马齿苋对草甘膦的抗药性

为明确棉田反枝苋和马齿苋对草甘膦的抗性水平,采用培养皿种子法和整株检测法分别测定了7个省18个采样点反枝苋、马齿苋的抗性水平,并采用紫外分光光度计测定采样点反枝苋、马齿苋体内莽草酸含量变化的差异。结果表明:采样点地区的反枝苋和马齿苋对草甘膦存在不同程度的抗药性,2种监测法的抗性趋势基本一致,其中陕西西安采样点的反枝苋和新疆疏勒采样点的马齿苋处于敏感水平,河北曲周采样点的反枝苋抗性倍数最高。植物体内莽草酸积累变化与植物抗性水平相关,抗性较低的植物体内莽草酸积累量普遍高于抗性较高的植物。     

湖南省部分地区棉田牛筋草(Eleusine indica)对高效氟吡甲禾灵的抗药性

为制定棉田恶性杂草牛筋草的防除策略和延缓抗性种群发展,采用整株测定法测定了湖南省部分地区棉田杂草牛筋草(Eleusine indica)对高效氟吡甲禾灵的抗药性水平,并通过测定谷胱甘肽-S-转移酶(GST)活力研究了牛筋草对高效氟吡甲禾灵的代谢抗性机制。整株法测定结果显示,相对于敏感的鼎城区种群,不同地区牛筋草种群对高效氟吡甲禾灵均产生了不同程度的抗药性,抗药性指数在2.4~18.4。其中汉寿牛筋草种群的抗性水平最高,其次是大通湖、湘阴种群。汉寿抗性牛筋草种群GST活力明显高于鼎城区敏感种群,表明GST对高效氟吡甲禾灵代谢能力的差异是牛筋草对高效氟吡甲禾灵产生抗药性的一个重要原因。     

广东发现对百草枯、草甘膦和草铵膦均产生抗药性的牛筋草种群

<正>华南农业大学农学院通过比较分析牛筋草对百草枯、草甘膦和草铵膦的抗药性指数,旨在筛选出对3种除草剂产生多抗性的牛筋草种群,为杂草抗药性机制的深入研究及其合理治理奠定基础。研究人员以采集于广东省不同地区的13个牛筋草种群为材料,采用整株生物测定法对牛筋草种群进行了百草枯和草铵膦抗药性水平测定,并采用培养皿法和莽草酸含量法对牛筋草种群进行草甘膦抗药性水平测定。     

湖南省局部棉田牛筋草对高效氟吡甲禾灵已产生抗药性

<正>为制定棉田恶性杂草牛筋草的防除策略和延缓抗性种群发展,湖南农业大学植物保护学院联合湖南省农业科学院研究人员采用整株测定法测定了湖南省部分地区棉田杂草牛筋草(Eleusine indica)对高效氟吡甲禾灵的抗药性水平,并通过测定谷胱甘肽-S-转移酶(GST)活力研究了牛筋草对高效氟吡甲禾灵的代谢抗性机制。     

湖南省部分地区油菜田看麦娘对精喹禾灵已产生抗性

<正>湖南省农业科技人员近期采用培养皿种子萌发法和盆栽法,测定了该省境内长沙、永州、常德、益阳、浏阳、岳阳、娄底等7个市州10个地区油菜田看麦娘潜在抗药性种群对精喹禾灵的抗性水平,测定了常德市桃源地区看麦娘潜在抗药性种群以及敏感种群谷胱甘肽-S-转移酶(GSTs)对精喹禾灵的敏感性,对桃源地区看麦娘抗性品系及敏感品系ACCase基因片段进行扩增和测序,比较了两种生物型的基因序列。培养皿种子萌发法测定结果表明:常德市桃源地区看麦娘抗     

转基因抗草甘膦棉花及其对草甘膦抗性的时空表达

草甘膦是一种非选择性除草剂,它通过竞争性抑制莽草酸途径中的5-烯醇丙酮莽草酸-3-磷酸合酶（EPSP合酶）干扰芳香族氨基酸的生物合成而发挥毒性作用。虽然获得抗草甘膦棉花的途径有多种,但当前用于生产的抗草甘膦棉花主要是以CP4- EPSPS基因转化棉花获得的。草甘膦对转CP4- EPSPS棉花的营养生长没有不利影响,但4叶期后喷施草甘膦会显著降低花粉粒的活性,抑制散粉、授粉和结实,导致转CP4- EPSPS棉花对草甘膦抗性呈现出一定程度的时空变化。草甘膦对抗草甘膦棉花（雄性）生殖器官的抑制效应一方面源于草甘膦在生殖器官内的大量积累,另一方面在于CP4- EPSPS基因在（雄性）生殖器官的低效表达。促进CP4- EPSPS基因在全株高效表达是提高棉花对草甘膦抗性的重要途径。     

土壤宏基因组中抗草甘膦新基因的克隆与转化水稻的研究

EPSPS (5-烯醇丙酮莽草酸-3-磷酸合酶EC 2.5.1.19)是植物芳香族氨基酸和植物次生代谢产物生物合成中莽草酸途径的关键酶; 同时也是广谱性除草剂草甘膦的作用目标。本实验通过对草甘膦污染土壤宏基因组文库的建立及筛选, 成功克隆了一个新的草甘膦抗性的EPSPS基因(命名为soilEPSPS)。序列分析表明soilEPSPS基因全长1404 bp, 其编码的467个氨基酸中未涉及已公布专利中保护的氨基酸序列。原核功能验证表明该基因对草甘膦的耐受能力优于EPSPS CP4基因。将该基因与水稻Rubisco SSU引导肽相融合构建由actin启动子驱动的植物表达载体, 用农杆菌介导法实现了水稻的遗传转化。抗性再生植株的PCR和Southern杂交结果表明所获得的26株再生植株均为转基因阳性植株, 其中共有3个单拷贝转化事件。草甘膦抗性鉴定证明纯合体T₂代植株能够耐受高达500 mmol L^-1的草甘膦。本研究为转基因抗除草剂水稻新品种的培育奠定了基础。     

辽宁省稻田野慈姑已对苄嘧磺隆产生抗药性

<正>为明确辽宁省不同稻田区野慈姑对苄嘧磺隆的抗性水平,沈阳农业大学植物保护学院整株测定了辽宁省大石桥(种群R1)、海城(种群R2)、苏家屯(种群R3)和开原(种群R4)共4个水稻产区野慈姑对苄嘧磺隆的抗性水平,并离体测定了各种群叶片体内乙酰乳酸合成酶(ALS)对苄嘧磺隆的敏感性。结果显示,种群R1和R2的抗药性相对较高,抗性指数分别为     

棉花花生间作田中花生蚜对吡虫啉代谢抗性机制初步研究

【目的】探讨棉花花生间作田中棉蚜(Aphis gossypii Glover)和花生蚜(Aphis craccivora Koch.)对吡虫啉抗性的差异以及花生蚜对吡虫啉代谢抗性的机制,以科学有效防治这一类害虫,避免其对吡虫啉的抗性快速发展。【方法】采集山东巨野和临清2个地区的棉花花生间作农田中的棉蚜和花生蚜,对这两个地区的地理种群和室内敏感品系进行了吡虫啉的室内毒力测定;使用增效剂顺丁烯二酸二乙酯(Diethyl maleate, DEM)、胡椒基丁醚(Piperomyl butoxide, PBO)和磷酸三苯酯(Triphenyl phosphate, TPP)3种增效剂进行了增效剂效果试验;并检测了2个地理种群和室内敏感品系花生蚜细胞色素P450单加氧酶(Cytochrome P450 monooxygenase,P450)、谷胱甘肽S-转移酶(Glutathione S-transferase, GST)和羧酸酯酶(Carboxylesterase, CarE)3种解毒代谢酶的活性。【结果】临清和巨野2个地区的棉蚜对吡虫啉抗性处于中等水平,抗性倍数分别为43.2倍和54.6倍;而花生蚜对吡虫啉则处于敏感或低水平抗性,2个种群抗性倍数分别为3.7倍和8.3倍。防治花生蚜的增效剂试验结果表明,巨野种群中,PBO、DEM对吡虫啉具有显著的增效作用,增效比分别达到3.63、1.95,而TPP不具有增效作用;在临清种群中,PBO对吡虫啉具有显著的增效作用,增效比达到3.05,而DEM和TPP不具有增效作用。对花生蚜的代谢酶活力测定发现,巨野种群与敏感品系相比,CarE活性没有显著差异,而P450和GST活性显著高于敏感品系;临清种群与敏感品系相比,CarE和GST活性无显著性差异,而P450活性显著高于敏感品系。【结论】间作农田中2种蚜虫对吡虫啉的敏感性差异较大,需要合理施药延缓抗药性的增强,同时推断P450和GST在花生蚜对吡虫啉的抗药性中发挥一定的作用。     

“抗病值”大豆抗孢囊线虫病遗传研究中应用的探讨

以抗病值表示大豆单株对孢囊线虫的抗性,探讨其在大豆对孢囊线虫４号生理小种抗性遗传 研究中的应用。在所研究的４个高感×高抗杂交组合中,直接用孢囊数作为抗性的参数,不分离群体 具有较大的方差,群体平均数与方差有较强的正相关;而采用抗病值表示抗性,不分离群体有较小的 方差,但Ｆ_２分离群体方差较大。与原始数据相比,经平方根转化后,单株孢囊数的群体平均数与方差 的高度正相关只有轻微的下降;而单株抗病值的群体平均数与方差的相关性则明显降低。４个组合单 株抗病值的广义遗传力为５７．４９％～７１．７９％,高于单株孢囊数的４８．４２％～６５．９６％;根据抗病值推导 出的最小基因数目为３～４,比用孢囊数推导为２～３的结果更接近按质量性状遗传估算出的结果。对 Ｆ_２单株频次分布研究表明,采用抗病值标准品种法分级统计的高抗株数,与按全国抗性分级标准下＜ １０个孢囊／株的株数完全一致,而且得到了更广泛的中间类型分布。按质量性状遗传模式对４个高感 ｘ高抗组合Ｆ_２分离群体研究表明,灰皮支黑豆和元钵黑豆对ＳＣＮ４号生理小种的抗性遗传可能由三 对隐性基因和二对显性基因控制。     

“抗病值”在大豆抗孢囊线虫病遗传研究中应用的探讨

以抗病值表示大豆单株对孢囊线虫的抗性， 探讨其在大豆对孢囊线虫4号生理小种抗性遗传研究中的应用。 在所研究的4个高感×高抗杂交组合中， 直接用孢囊数作为抗性的参数， 不分离群体具有较大的方差， 群体平均数与方差有较强的正相关； 而采用抗病值表示抗性， 不分离群体有较小的方差， 但F2分离群体方差较大。 与原始数     

Fungitoxic effect of scopolin and related coumarins on Sclerotinia sclerotiorum. A way to overcome sunflower head rot

Summary The content of coumarins, as probable phytoalexins, was analysed in four sunflower genotypes that ranged in responses to head rot from highly susceptible to highly resistant. Low levels of all coumarins (scopolin, scopoletin and ayapin) were detected in the three most susceptible genotypes irrespective of time after inoculation. However, in the resistant genotype there was a clear time-dependent disease-induced increase of all coumarins that reached a maximum after 10–14 days. Detailed comparison of the most susceptible and the resistant genotype showed that in the resistant but not the susceptible, scopoletin peroxidase activity increased during the course of the experiment. Results confirmed a clear negative correlation between coumarin content and disease symptoms and in particular for scopolin. Furthermore we show for the first time that scopolin is inhibitory to Sclerotinia at similar doses to scopoletin. As scopolin is known to be less phytotoxic than ayapin and scopoletin, its accumulation may well confer head rot resistance with minimal plant damage and might be one of the bases for resistance to Sclerotinia.     

半野生棉与亚洲棉对草甘膦抗性评价及比较分析

采用叶片棉球定位鉴定法,初步鉴定并评价了半野生棉和亚洲棉对草甘膦的自然抗性,结果表明:参试材料抗性水平从高抗至高感分6级,极端抗性水平相差33.3倍(0.2%对0.006%)。其中,半野生棉对草甘膦的自然抗性分级丰富,抗性水平分布自高抗至高感;但大部分半野生棉不耐草甘膦,近86%(346份)的材料抗性水平处于低耐级别以下。而亚洲棉抗性水平都处于高抗至低耐的4个级别,抗性多样性较差,但整体抗性水平较高,70.3%(71份)表现为耐或以上级别。从半野生棉和亚洲棉中分别筛选到2份和5份高抗材料,半野生棉中有1份高感材料,亚洲棉中无对草甘膦敏感材料。本研究报道的极端材料为棉花草甘膦抗性遗传机制研究、新品种的培育、内源抗性基因的挖掘和感抗机理研究,奠定了良好的材料基础。     

Glyphosate accumulation,translocation, and biological effects in Coffea arabica after single and multiple exposures

In perennial crops like coffee, glyphosate drift exposure can occur multiple times during its commercial life span. Due to limited glyphosate degradation in higher plants, a potential accumulation of glyphosate could lead to increased biological effects with increased exposure frequency. In this study, we investigated glyphosate translocation over time, and its concentration and biological effects after single and multiple simulated spray-drift exposures. Additionally, shikimic acid/glyphosate ratios were used as biomarkers for glyphosate binding to its target enzyme.Four weeks after the exposure, glyphosate was continuously translocated. Shikimic acid levels were linear correlated with glyphosate levels. After two months, however, glyphosate appeared to have reduced activity. In the greenhouse, multiple applications resulted in higher internal glyphosate concentrations. The time of application, however, was more important regarding biological effects than the number of applications both in the greenhouse and in the field. In the field, berry yield, the most important biological response variable, was reduced 26% by the first out of four sequential applications of glyphosate at 64 g a.e. ha⁻¹ each. The three subsequent applications did not reduce yield any further.     

Variation in performance of western flower thrips populations on a susceptible and a partially resistant chrysanthemum cultivar

Variation in host plant performance among populations of a phytophagous insect pest is a potential threat to the durability of host plant resistance. Aggressive biotypes may overcome the protective properties of formerly resistant cultivars. Therefore, it is of interest to study such variation in breeding programs for host plant resistance to insects. In the present study, the performance of ten populations of Frankliniella occidentalis, the western flower thrips, was determined on a susceptible and a partially resistant cultivar of chrysanthemum, Dendranthema grandiflora. Damage, reproduction, and adult survival were determined using an excised leaf assay. Significant differences between the two cultivars and among the ten populations were found for all three characteristics. In general, damage, reproduction and adult survival were reduced on the resistant cultivar when compared to the susceptible cultivar. Some populations showed, in comparison to the reference population from the Netherlands, much higher damage and reproduction on one or both chrysanthemum cultivars. But also in these populations performance on the resistant cultivar was poor compared to the susceptible cultivar. This revised version was published online in August 2006 with corrections to the Cover Date.