海南地区豆大蓟马田间种群的抗药性监测

采用叶管药膜法(TIBS)室内测定了2014-2015年海南主要豇豆种植区三亚、澄迈和海口豆大蓟马田间种群对6种常用杀虫剂敏感性的年度变化。结果表明,2014年,三亚种群对甲维盐、高效氯氰菊酯和吡虫啉产生了低水平抗性,抗性倍数分别为5.39、8.07和5.44倍,澄迈种群对甲维盐也产生了5.93倍的低水平抗性,海口种群对药剂仍处于敏感阶段;2015年,三亚种群对甲维盐、乙基多杀菌素、吡虫啉和啶虫脒产生了低水平抗性,抗性倍数分别为7.97、5.43、7.51和5.44倍,对高效氯氰菊酯产生了中等水平抗性,抗性倍数为12.99倍;澄迈种群和海口种群对除甲维盐外的其它药剂仍处于敏感状态,但年度间相比,均表现出药剂敏感性下降,有进一步产生低水平抗性的趋势。海南各监测地区均未发现豆大蓟马对阿维菌素产生抗性,可以考虑其它药剂与阿维菌素轮换使用。     

普通大蓟马对寄主植物及其挥发物的行为反应

普通大蓟马Megalurothrips usitatus(Bagnall)是我国华南地区豆科植物上的重要害虫,并已对多种农药产生严重的抗药性,为减少化学农药的使用,探寻基于寄主植物挥发物的化学生态调控技术,针对不同寄主植物及其挥发性信息化合物对普通大蓟马的行为影响进行研究和探讨.本研究采用\"Y\"型嗅觉仪测定了普通大蓟马对豇豆花和四季豆花的选择行为,在此基础上再利用\"Y\"型嗅觉仪和四臂嗅觉仪测定了普通大蓟马对不同生理期及不同为害程度的豇豆花的选择行为,筛选该虫的嗜好寄主及其生理状态.分别以正己烷和甲醇作为溶剂,应用顶空动态吸附法和溶剂浸取法提取寄主植物挥发物,利用气相色谱-质谱联用仪(GC-MS)对其成分进行分析和鉴定.通过\"Y\"型嗅觉仪测定普通大蓟马对上述挥发物的不同浓度的标样及其混配物的行为反应,结果表明豇豆花对普通大蓟马的引诱活性显著高于四季豆花,后续试验进一步表明健康豇豆花对普通大蓟马的引诱效果好于花蕾、虫蕾和虫花.利用GC-MS从普通大蓟马嗜好寄主健康豇豆花中初步鉴定出42个挥发性信息化合物主要化学成分,购买标样对普通大蓟马进行不同浓度的行为活性测定,发现10-4β-石竹烯、10-2植物醇、10-6棕榈酸乙酯和10-6邻二甲苯具极显著的引诱作用,10-4罗勒烯、10-4亚油酸甲酯、10-4棕榈酸甲酯、10-4甲酯、10-62-甲基-3-羟基-4-吡喃酮具极显著的驱避作用,而棕榈酸乙酯在高浓度时表现出驱避作用,低浓度时表现出引诱作用.此外,当邻二甲苯和β-石竹烯、邻二甲苯和棕榈酸乙酯浓度为10-6时,其混配物对普通大蓟马表现出极显著的驱避作用,本试验尚未发现可增强引诱活性的配方.健康豇豆花为普通大蓟马的嗜好寄主,从其挥发性信息化合物中鉴定筛选出一批对普通大蓟马具显著引诱或驱避活性的化合物,为探明普通大蓟马对寄主植物的反应机制提供了信息基础,亦为今后研发高活性引诱剂或驱避剂提供理论基础.     

土壤含水量和土壤类型对豆大蓟马蛹期发育和羽化的影响

豆大蓟马Megalurothrips usitatus(Bagrall)是近年来严重制约海南豇豆生产的重要害虫。针对该蓟马在土壤中化蛹的习性,本文研究了在室内条件下不同土壤含水量和土壤类型对豆大蓟马化蛹的影响。结果表明,土壤含水量和土壤类型显著影响豆大蓟马蛹的发育历期和羽化率,土壤含水量为15%且土壤类型为砂壤土时,豆大蓟马的发育历期最短为3.62±0.15 d,羽化率最高为52.08%±0.07%,低含水量(5%)和高含水量(25%)均不利于豆大蓟马化蛹。土壤类型以砂壤土最适宜豆大蓟马化蛹,粘土最不适合豆大蓟马化蛹,其羽化率最低为19.17%±0.02%。     

斯氏钝绥螨对西花蓟马和豆大蓟马若虫的捕食功能反应

【目的】为明确斯氏钝绥螨Amblyseius swirskii对西花蓟马Frankliniella occidentalis和豆大蓟马Megalurothrips usitatus不同龄期若虫的捕食量及控制潜能。【方法】在25℃和75%相对湿度下,研究了斯氏钝绥螨雌成螨对两种蓟马1龄和2龄若虫的捕食喜好性、功能反应以及捕食螨自身的干扰反应。【结果】斯氏钝绥螨无论对西花蓟马还是豆大蓟马,在各自1龄和2龄若虫共存状况下,对1龄若虫的喜好性均显著高于2龄。捕食螨对两种蓟马1龄若虫的捕食量和喜好性无显著差异,但对西花蓟马2龄若虫的捕食量和喜好性显著大于豆大蓟马2龄若虫。斯氏钝绥螨雌成螨对西花蓟马和豆大蓟马的1龄若虫和2龄若虫的捕食功能反应均符合HollingⅡ型方程。捕食螨对西花蓟马和豆大蓟马1龄若虫的日均捕食量均随其自身密度的增加而逐渐降低。【结论】斯氏钝绥螨的捕食量与蓟马的种类和龄期有关,也与捕食螨的密度有关。     

三类次生共生菌在豆大蓟马体内分布以及不同因子对其含量的影响

【目的】本研究旨在研究豆大蓟马Megalurothrips usitatus体内次生共生菌Rickettsia,Wolbachia和Arsenophonus的分布模式以及虫生真菌侵染、温度、寄主植物、啶虫脒抗性对Rickettsia,Wolbachia和Arsenophonus含量的影响,为深入了解这些次生共生菌在豆大蓟马中的潜在功能奠定基础,为开发新型生物防治策略提供理论支持。【方法】采用荧光原位杂交(fluorescence in situ hybridization, FISH)技术检测Rickettsia,Wolbachia和Arsenophonus在豆大蓟马雌雄成虫和2龄若虫体内的分布;通过RT-qPCR检测取食球孢白僵菌Beauveria bassiana孢悬液(1×10～8孢子/mL)浸泡的豇豆Vigna unguiculata、不同温度(5, 10, 15, 25, 30, 35和45℃)处理、取食寄主植物豇豆和刀豆Canavalia gladiata的豆大蓟马及啶虫脒敏感品系与抗性品系豆大蓟马成虫中Rickettsia,Wolbachia和Arsenophonus的含量。【结果】Rickettsia和Wolbachia广泛分布于豆大蓟马的成虫和2龄若虫中,主要位于胸部和腹部,少量分布于口器和尾部;Arsenophonus仅在豆大蓟马雌成虫腹部发现。与对照相比,球孢白僵菌感染4 d时豆大蓟马雌成虫中Rickettsia的含量开始显著增加,Wolbachia的含量先增加后减少,Arsenophonus的含量直到6 d时显著增加。豆大蓟马成虫中Rickettsia,Wolbachia和Arsenophonus含量在25℃下最高,在其他温度下则有不同程度的下降;与取食豇豆的豆大蓟马相比,取食刀豆后豆大蓟马成虫中Rickettsia含量显著降低;与啶虫脒敏感品系相比,豆大蓟马啶虫脒抗性品系成虫中Rickettsia,Wolbachia和Arsenophonus含量显著增加。【结论】Rickettsia和Wolbachia广泛分布于豆大蓟马成虫和2龄若虫中,而Arsenophonus仅存在于豆大蓟马雌成虫体内;真菌侵染、温度、寄主植物和杀虫剂等因子动态调控Rickettsia,Wolbachia和Arsenophonus的含量。上述研究结果突显了次生共生菌的生态可塑性,为其在害虫靶向性防控策略中的应用提供了理论依据。     

杀虫剂亚致死浓度对普通大蓟马繁殖的影响

【目的】在中国海南省,普通大蓟马Megalurothrips usitatus(Bagrall)是豇豆Vigna unguiculata(L.)Walp.上的重要害虫,化学防治还是重要的控制手段。本研究旨在了解3种杀虫剂亚致死浓度对该虫繁殖的影响。【方法】在(26±1)℃、相对湿度60%±5%、光周期L∶D=14∶10条件下,采用叶盘浸药法测定溴氰虫酰胺、双甲脒和茚虫威48 h内对普通大蓟马1日龄已交配雌虫的毒杀效果。经杀虫剂LC20处理的幼嫩豇豆叶叶盘供已交配雌虫和未交配雌虫取食48h后,改用未浸药叶盘继续饲养。每天观察雌虫所产子代的卵数和成虫数,计算已交配雌虫的子代成虫性比和卵性比。【结果】3种杀虫剂LC20处理均使亲代雌虫的存活时间显著缩短。溴氰虫酰胺和双甲脒LC20处理还能显著降低已交配亲代雌虫在胁迫处理后所产子代的成虫数量。亲代雌虫经溴氰虫酰胺、双甲脒和茚虫威LC20处理后的子代成虫性比分别为0.60、0.47和0.41,与清水对照(0.52)之间的差异均未达显著水平;卵性比在各处理之间都没有显著差异。【结论】溴氰虫酰胺、双甲脒和茚虫威LC20处理对普通大蓟马亲代雌虫的存活时间和子代成虫数量有不同程度的负面影响,但对子代性别分配均没有显著的干扰作用。     

关于苦马豆属学名的讨论

本文根据国内外豆科研究文献的考证,讨论了苦马豆属(Sphaerophysa DC.)及其近缘属的区别,重新确认了国产苦马豆属和苦马豆的学名。     

普通大蓟马聚集信息素的分离和鉴定

【目的】普通大蓟马Megalurothrips usitatus是我国华南地区重要的豆科害虫,给我国豇豆种植产业带来巨大损失。开发利用基于聚集信息素的引诱剂是普通大蓟马的绿色防控措施之一,对于普通大蓟马生物防治具有重要意义。【方法】采用Y型嗅觉仪测定普通大蓟马雌雄成虫对其雌虫和雄虫气味源的嗅觉反应;用顶空固相微萃取法(head space solid-phase microextraction, HS-SPME)和溶液浸提法提取普通大蓟马雌雄成虫挥发物;应用气质联用仪(gas chromatography-mass spectrometry, GC-MS)对收集的气体挥发物和正己烷提取物进行活性成分分离鉴定;应用Y型嗅觉仪测定人工合成聚集信息素组分对雌雄成虫的引诱效果。【结果】行为学试验结果表明,普通大蓟马雄成虫气味源对其雌雄成虫均具有显著的引诱作用,而雌成虫气味源则没有。顶空固相微萃取法和溶液浸提法均可提取雄成虫挥发物主要组分,但顶空固相微萃取法获得的TIC图基线平稳,杂峰少,提取效果优于溶剂浸提法。GC-MS分析结果表明,普通大蓟马雄成虫挥发物中主要含有 1种化合物,为反式,反式-金合欢醇乙酸酯［(E,E)-farnesyl acetate］,该化合物在雌成虫挥发物中不存在。室内行为学实验结果表明,特定剂量的人工合成的(E,E)-farnesyl acetate对普通大蓟马雌雄成虫均具有显著的引诱作用。【结论】本研究证明了普通大蓟马雄成虫可以释放聚集信息素,并鉴定了其主要组分(E,E)-farnesyl acetate,为应用聚集信息素开展普通大蓟马的监测和诱杀提供了基础。     

苦马豆的组织培养(简报)

以苦马豆种子在MS无植物生长调节剂的培养基上培养出无菌苗,以子叶和胚轴为外植体,在MS＋6．BA2．0mg／L＋2,4-D0．Smg／L上诱导产生愈伤组织,在MS＋6-BA2．0mg／L＋NAA0．Smg／L培养基上继代培养,继代三次后在MS＋6-BA2．0mg/L培养基上诱导产生丛芽,在MS＋6-BA0．5mg／L培养基上进行幼苗培养,在幼苗长到3～4cm时移至1／2MS＋IBA2．0mg／L培养基上生根。     

普通大蓟马对不同颜色的趋性及日节律调查

【目的】探明普通大蓟马Megalurothrips usittus(Bagrall)的嗜好颜色及其田间日活动节律。【方法】分别在室内和田间对10种不同颜色色板(白色、黑色、灰色、红色、绿色、黄色、蓝色、紫色、粉色和浅蓝色,佳多~?进行了非选择性试验,并通过将RGB颜色值转换为虚拟波长进行最嗜颜色量化非选择性试验,然后选择引诱效果最好的色板对普通大蓟马进行日活动节律调查。【结果】室内和田间选择试验表明蓝色对普通大蓟马的吸引率显著高于其它颜色,其次是浅蓝色和紫色;由RGB颜色值转换虚拟波长得到普通大蓟马最嗜颜色对应的波长为470 n(RGB值为0,193,255,蓝色);通过蓝板调察普通大蓟马日活动节律发现,普通大蓟马成虫种群活动节律明显,活动规律呈单峰型,活动最高峰为8:00-10:00,夜间(20:00—次日6:00)几乎不活动。【结论】研究结果为基于颜色趋性的普通大蓟马田间监测和综合治理提供了理论基础和科学依据。     

草地贪夜蛾对2种豆科蔬菜的取食和产卵选择性及其适应性研究

草地贪夜蛾Spodoptera frugiperda是一种多食性昆虫,为明确该害虫对不同寄主的选择性和适生性,本文比较了草地贪夜蛾对玉米Zea mays、豇豆Vigna unguiculata和四季豆Phaseolus vulgaris等3种寄主的取食及产卵偏好性,并分析了取食不同寄主对其生长发育及繁殖的影响。结果表明：草地贪夜蛾低龄幼虫(初孵幼虫和2龄)对玉米叶和豇豆叶表现出取食偏好性,而高龄幼虫(3龄和5龄)对3种寄主不同组织的取食选择性无明显差异;草地贪夜蛾取食3种寄主植物均可以完成世代发育,但取食豇豆叶和四季豆叶的幼虫历期、蛹历期显著变短,化蛹率、羽化率显著降低;取食豇豆叶对其蛹重、成虫寿命无显著影响,但取食四季豆叶的蛹重显著变轻、雄成虫寿命显著变短;种群生命表参数显示,草地贪夜蛾在3种寄主上的繁殖力表现为玉米叶(1 138.29)>豇豆叶(1 179.00)>四季豆叶(585.50),处理间差异显著;取食2种非嗜好寄主的种群内禀增长率(r_m)和周限增长率(λ)均显著降低,平均世代历期(T)显著延长,取食豇豆叶的雌雄性比显著降低;草地贪夜蛾对寄...     

High temperature effects on photosynthesis and water relations of grain legumes

Effects of high temperature on photosynthesis, and its interaction with water relations in common bean (Phaseolus vulgaris), cowpea (Vigna unguiculata), faba bean (Vicia faba), and five cultivars of field pea (Pisum sativum) were investigated. Responses of all species were compared at 20/15, 30/15, or 30/25 °C day/night, and cowpea and pea were compared at 20/15 and 30/25 °C under well-watered and limited-water conditions. Response of pea to 20/15 and 30/25 °C during flowering was ascertained, and sensitivity of the photosystem of pea and faba bean to 40 °C was determined.High temperature decreased chlorophyll variable fluorescence (F_v), a measure of injury to photosynthesis, in all species except cowpea, which was highly tolerant. Leaf chlorophyll and most measures of growth were favored by high day temperature but not by high night temperature, and photosynthetic rates were enhanced by high temperatures that increased leaf chlorophyll and nitrogen (N) contents. High temperature diminished growth less than water deficiency and increased water use of all three species but only lowered the water potential in faba bean. Water deficiency generally decreased growth, water use, and water potential more at 30/25 °C than at 20/15 °C. Stress from high temperature during flowering of pea decreased all components of yield at maturity, particularly at nodes that flowered latest. Whole-chain photosynthetic activity in thylakoids of pea, faba bean, and wheat (Triticum aestivum) were equally sensitive to high temperature, suggesting that Photosystem Il was the most labile component. The results show that high temperature affects photosynthesis, growth, and water relations of grain legumes, and sensitivity to the stress differs among species and genotypes.     

Bradyrhizobium elkanii, Bradyrhizobium yuanmingense and Bradyrhizobium japonicum are the main rhizobia associated with Vigna unguiculata and Vigna radiata in the subtropical region of China

Cowpea (Vigna unguiculata) and mung bean (Vigna radiata) are important legume crops yet their rhizobia have not been well characterized. In the present study, 62 rhizobial strains isolated from the root nodules of these plants grown in the subtropical region of China were analyzed via a polyphasic approach. The results showed that 90% of the analyzed strains belonged to or were related to Bradyrhizobium japonicum, Bradyrhizobium liaoningense, Bradyrhizobium yuanmingense and Bradyrhizobium elkanii, while the remaining represented Rhizobium leguminosarum, Rhizobium etli and Sinorhizobium fredii. Diverse nifH and nodC genes were found in these strains and their symbiotic genes were mainly coevolved with the housekeeping genes, indicating that the symbiotic genes were mainly maintained by vertical transfer in the studied rhizobial populations.     

Low-temperature limitations of photosynthesis in three tropical Vigna species: A chlorophyll fluorescence study

The temperature-dependence of photosynthesis and chlorophyll (Chl) fluorescence quenching components was studied between 0 and 45°C in three tropical, chilling-sensitive Vigna species and in chilling-tolerant pea. Photosynthesis of the Vigna spp. was approx. 20% more reduced by temperatures between 7 and 30°C than in pea. The latter revealed significant changes in Chl fluorescence parameters at much lower temperature than the Vigna spp. Below 15°C, the reduction state of Q_A increased quickly in pea, while in Vigna already below 30°C, an increase of reduced Q_A was obtained. The analysis of different components of non-photochemical Chl fluorescence quenching (q_N) revealed, that in pea photoinhibitory quenching (q_I) occurred below 13°C. Below ca. 7°C, a sudden breakdown of both q_P and the fast relaxing component of q_N was observed in pea.In Vigna, susceptibility of LHC II phosphorylation or limitation of electron flow by damage to PS I, the PS II reaction centre or the water-splitting system were not responsible for the chilling-sensitivity of photosynthesis between 5 and 30°C. Instead, photosynthesis was gradually limited by an inefficient use of reduction equivalents. This, in turn may increase susceptibilty to photoinhibition, which occurred below 20°C in Vigna. The combined study of q_P and of the different components of q_N allowed the demonstration of the subsequent occurrence of different limiting processes with decreasing temperature in the chilling-sensitive Vigna species.