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1.
玉米大斑病菌生理小种研究初报 总被引：14，自引：2，他引：12
1980年至1981年两年的试验结果表明:我国玉米大斑病菌存在着两个生理小种,即生理小种1号和生理小种2号。病菌标样采自辽宁、广西、浙江、陕西、黑龙江等地玉米大斑病菌共105个标样,病菌经分离培养接种在具有Ht1、,Ht2单基因抗性寄主以及多基因抗性寄主上。测定结果证明:接种在具有Ht1、Ht2单基因抗性寄主上表现为褪绿斑的菌株,属于生理小种1号,其毒力公式为Ht1Ht2/O (有效抗性基因/无效寄主基因)。接种在具Ht1单基因抗性寄主上表现有毒力产生萎蔫斑,而对Ht2鉴别寄主表现无毒力产生褪绿斑的菌株属于生理小种2号,其毒力公式为Ht2/Ht1。
目前玉米大斑病菌生理小种2号只在辽宁发现,尤以丹东地区出现频率较高。 相似文献
目前玉米大斑病菌生理小种2号只在辽宁发现,尤以丹东地区出现频率较高。 相似文献
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会宁剖面MIS3阶段黄土元素地球化学特征及气候变化 总被引：1，自引：0，他引：1
在会宁剖面元素地球化学数据分析和气候替代指标分析的基础上，重建了会宁地区约20～70 ka的古气候特征和序列。研究表明：Ba、Rb、Sr、Ti、Fe2O3、SiO2、Al2O3、MgO、K2O等在剖面上都有随深度的减小含量随之增加的趋势；CaO、Na2O等在剖面上有随深度的减小含量随之减小的趋势。MIS3气候略显温湿，可划分为3个阶段：早期(L1S1S2)，55.5～45.9 ka，气候为弱温湿；中期(L1S1L1)，45.9～27.3 ka，气候为干冷；晚期(L1S1S1)，27.3～23.8 ka，气候为温湿；会宁剖面较明显地记录了5次Heinrich事件。 相似文献
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为探究CO2浓度升高、增温以及二者交互作用对谷子各生育期土壤微生物生物量的影响,采用盆栽试验,通过人工气候室控制环境CO2浓度和温度,设置对照(400μmol·mol-1 CO2浓度和22℃环境温度,CK)、CO2浓度升高(700μmol·mol-1 CO2浓度和22℃环境温度,EC)、 CO2浓度升高和增温4℃(700μmol·mol-1 CO2浓度,26℃环境温度,EC+T)3种气候条件,且每个气候条件均设置充分供水（70.0%田间持水量）和轻度干旱（50.0%田间持水量）两种水分处理,分析CO2浓度升高、增温4℃以及二者交互作用对谷子各生育期（开花期、开花后10 d、灌浆期、成熟期）土壤微生物生物量碳（MBC）、土壤微生物生物量氮（MBN）、土壤微生物生物量磷（MBP）的影响。结果表明:在充分供水条件下,CO2浓度升高使... 相似文献
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种子引发处理对无籽西瓜幼苗生长的影响和对细菌性果斑病菌消毒的效果 总被引：2，自引：0，他引：2
种子出苗率低和传带细菌性果斑病菌是制约三倍体无籽西瓜生产的主要原因。本试验利用KMnO4、CuSO4和ZnSO4的不同浓度溶液对无籽西瓜种子进行不同时间引发处理, 通过滤纸发芽试验, 观测其对种子发芽和幼苗生长的促进作用;借助平板法测定引发溶液对细菌性果斑病菌FC247的抑制作用, 免疫凝聚试纸条和传统PCR检测引发处理对种子人工接菌FC247的消毒效果。结果表明:0.1% CuSO4溶液引发处理4 h和0.2% ZnSO4溶液引发处理24 h, 分别比未引发处理的无籽西瓜种子发芽率提高71.1%和73.3%, 并能显著提高发芽整齐度和幼苗素质;同时, 引发溶液对细菌性果斑病菌有显著抑制作用, 并对人工接菌种子表现出-定程度的消毒效果。 相似文献
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不同杀菌剂对黄瓜靶斑病菌的毒力作用特性比较 总被引：4，自引：2，他引：2
为筛选防治黄瓜靶斑病的有效药剂,采用菌丝生长速率法、孢子萌发法和芽管伸长法测定了19种杀菌剂对黄瓜靶斑病菌的毒力,探究了4种毒力较高杀菌剂对病原菌菌丝形态的影响。结果表明:氟啶胺、吡唑萘菌胺、咯菌腈和四霉素对黄瓜靶斑病菌菌丝生长、孢子萌发和芽管伸长各生长发育阶段均有较强的抑制活性,其中,4种药剂抑制菌丝生长的平均EC50值分别为0.516 3、1.538、1.605和0.648 2 mg/L,抑制孢子萌发的平均EC50值分别为0.164 4、1.359、1.127和0.002 5 mg/L,抑制芽管伸长的平均EC50值分别为0.189 6、0.144 7、0.060 4和0.001 5 mg/L;啶酰菌胺、百菌清和肟菌酯3种不同作用机制杀菌剂对黄瓜靶斑病菌孢子萌发和芽管伸长的抑制活性较强,3种药剂抑制孢子萌发的平均EC50值分别为1.564、0.373 0和0.021 3 mg/L,抑制芽管伸长的平均EC50值分别为0.629 5、0.233 4和0.405 0 mg/L,但对菌丝生长的抑制作用较弱,平均EC50大于16 mg/L;氟啶胺、吡唑萘菌胺、咯菌腈和四霉素可引起黄瓜靶斑病菌菌丝不同程度的异常生长,主要表现为菌丝隔膜间距变小、菌丝节间肿大、主菌丝上二次分枝发生频繁、菌丝变形黏连、菌丝新分枝处生长受抑制或分生孢子生长变形。研究表明,氟啶胺、吡唑萘菌胺、咯菌腈和四霉素对黄瓜靶斑病菌具有较高的毒力,在黄瓜靶斑病的田间防治中具有较好的开发应用潜力。 相似文献
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为探寻具有杀螨潜力的生防真菌,采用喷雾法测定分析玫烟色虫草Cordyceps fumosorosea IF-1106菌株和球孢白僵菌Beauveria bassiana BB-1339菌株对朱砂叶螨Tetranychus cinnabarinus和二斑叶螨Tetranychus urticae卵、幼螨及雌成螨的致病力。结果表明,感染玫烟色虫草IF-1106菌株和球孢白僵菌BB-1339菌株后螨类的形态特征不一致,感染IF-1106菌株后形成棉絮状菌丝,而感染BB-1339菌株后则形成羊毛状菌丝。IF-1106菌株和BB-1339菌株对朱砂叶螨和二斑叶螨卵的LC50分别为2.38×107、8.26×107CFU/mL和4.48×107、1.21×108CFU/mL,对朱砂叶螨和二斑叶螨幼螨的LC50分别1.97×107、8.26×107CFU/mL和7.65×106、8.99×105... 相似文献
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玉米大斑菌Ht-毒素组分分析 总被引：11，自引：1，他引：11
对分别属于玉米大斑病菌(Helminthosporium turcicum)1号和2号生理小种的致病毒素进行硅胶TL层析、薄层扫描和生物监测的结果发现,两个小种的毒性组分不同。2号小种可分离到I(Rf0.50)、Ⅱ(Rf0.36)、Ⅲ(Rf0.67)、Ⅳ(Rf0.80)、Ⅴ(Rf0.13)、Ⅵ(Rf0.25)6种组分,而1号小种最多可分离到除Ⅳ以外的其它5种组分,这些组分均有不同程度的紫外吸收。对在200~360nm有明显紫外吸收的4种组分(Ⅰ、Ⅱ、Ⅲ、Ⅳ)的生物监测结果表明,只有组分Ⅲ对带Ht1基因和不带Ht1基因的Oh43和B372对玉米自交系不具任何致病活性,组分Ⅰ、Ⅱ对不带Ht1基因的玉米自交系具有致病活性,而对带Ht1基因的玉米自交系却无毒性。值得重视的是组分Ⅳ的致病特性与组分Ⅰ、Ⅱ正好相反,即对带Ht1基因的玉米自交系具有致病活性,却对不带Ht1基因的玉米自交系没有致病作用。结论指出,Ht-毒素的TLC组分Ⅰ、Ⅱ、Ⅳ玉米斑菌诱致玉米发病的主要活性成份,其中组分Ⅳ是2号小种与Ht1基因玉米互作的特异性因子。 相似文献
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蜡质芽孢杆菌R2防治水稻纹枯病研究 总被引：8，自引：1，他引：8
选用我们从稻株上分离筛选的能促进水稻生长发育的蜡质芽孢杆菌(Bacillus cereus)R2号菌株,分别在室内和田间测定其对稻纹枯病菌(Rhizoctonia solani AG-1)的拮抗性和防病效果。在PDBA平板上,R2对病菌菌丝生长的抑菌带可达10.9mm宽。在WA平板上可抑制病菌菌核萌发,R2菌量为4×106、2×107、2×109cfu/ml时,病菌菌核萌发菌丝指数分别较对照降低28.2%、39.7%、56.4%。用菌量为2×109cfu/ml的R2菌液处理人工接种病菌的离体稻叶,对纹枯病病斑扩展的控制效果为55.5%,随R2菌量降低,其控制效果相应递减。用菌量为4×107cfu/ml的R2菌液喷施田间人工接种病菌的稻株,对纹枯病的防效可达43.8%。 相似文献
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陕西周原地区全新世黄土-古土壤序列风化程度研究 总被引：1，自引：0，他引：1
通过对周原LC全新世黄土-古土壤剖面的元素含量分布及其化学风化程度和元素迁移特征的研究。结果发现:古土壤S0的CIA和Rb/Sr值高于黄土L0,Na/K比低于黄土L0,指示其风化程度强于黄土L0,形成时期气候比黄土堆积时期温暖湿润;黄土风化成壤过程中,Si,K和Fe相对富集,而Ca,Na,Mg和Ti则迁移淋失,呈现Ca>Na>Mg>Ti>Al>Si>K>Fe的迁移序列;全新世剖面化学风化程度处于脱Na和Ca阶段或早期去K阶段。 相似文献
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Caroline Onfroy Alain Baranger Bernard Tivoli 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):13-27
The expression of partial resistance in pea to ascochyta blight (caused by Mycosphaerella pinodes) was studied in a detached stipule assay by quantifying two resistance components (fleck coalescence and lesion expansion)
using the method of point inoculation of stipules. Factors determining optimal conditions for the observation of partial resistance
are spore concentration, the age of the fungal culture prior to spore harvest and the pathogenicity of the isolate used for
testing. Partial resistance was not expressed when spore concentration was high or when the selected isolate was aggressive.
Furthermore, assessments of components of partial resistance were highly correlated with disease severity in a seedling test.
A screening protocol was developed based on inoculations of detached stipules to study partial resistance in pea. To simplify
the rating process, a more comprehensive disease rating scale which took into account fleck coalescence and lesion expansion
was tested by screening a large number of genotypes. 相似文献
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Grapevines of the Maltese islands were surveyed for the presence of virus diseases. Symptoms of fanleaf degeneration, leafroll, rugose wood and fleck were observed in the main grape-growing areas. The occurrence of these diseases was experimentally confirmed by graft transmission to woody indicators, which also revealed the presence of vein necrosis, a latent virus-like disorder. Viruses identified were grapevine fanleaf nepovirus, grapevine fleck virus, grapevine A closterovirus, grapevine leafroll-associated closteroviruses I and III. ELISA tests showed that 86% of 322 vines individually checked were infected by one or more viruses. 相似文献
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The population dynamics of two strains of Pseudomonas syringae pv. tabaci that cause the foliar spot diseases of tobacco known as wildfire (WF) and angular leaf spot (ALS) were significantly different in leaves of a susceptible tobacco cultivar. After 48 h the population of WF strains changed abruptly from exponential growth to stationary phase, whereas there was a more gradual transition by the ALS strains. This resulted in smaller stationary-phase populations for WF than for ALS. The decline of the WF population started soon after the stationary phase was reached, whereas the ALS stationary phase was relatively stable.
The strains reacted differently to climatic factors. On plants inoculated and exposed to the weather at weekly intervals, WF lesions grew faster when vapour pressure deficits, maximum temperatures and radiation were low. Multiple regression analysis showed that over 70% of the variation in WF infection was accounted for by variation in VPD, radiation and mean temperature. Variation in ALS infection was less easily explained in relation to the weather variables measured.
Plant age and stalk position had a differential effect on the pathogenicity of the two strains. Lower leaves of young plants (42 days) were most susceptible to WF and top leaves of older plants (84 days) were most susceptible to angular leaf spot. Differences in pathogenicity and occurrence in the field suggest that pathovar status should be considered for the ALS pathogen of tobacco. 相似文献
The strains reacted differently to climatic factors. On plants inoculated and exposed to the weather at weekly intervals, WF lesions grew faster when vapour pressure deficits, maximum temperatures and radiation were low. Multiple regression analysis showed that over 70% of the variation in WF infection was accounted for by variation in VPD, radiation and mean temperature. Variation in ALS infection was less easily explained in relation to the weather variables measured.
Plant age and stalk position had a differential effect on the pathogenicity of the two strains. Lower leaves of young plants (42 days) were most susceptible to WF and top leaves of older plants (84 days) were most susceptible to angular leaf spot. Differences in pathogenicity and occurrence in the field suggest that pathovar status should be considered for the ALS pathogen of tobacco. 相似文献
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Grapevines were surveyed for the presence of virus and virus-like diseases in the Albanian viticultural districts of Shkoder, Lesh, Kruje, Durres, Tirana, Elbasan, Lushnje and Vlora. Symptoms of grapevine degeneration, leafroll and rugose wood were observed in all areas surveyed, whereas fleck was found in volunteer plants of Vitis rupestris at Elbasan, and enation disease in a few vines near Durres. Viruses identified were grapevine fanleaf nepovirus, grapevine fleck virus, grapevine virus A, and grapevine leafroll-associated closteroviruses I and III. ELISA tests showed that 83.5% of 530 Vitis vinifera vines and 46% of 24 American rootstocks individually checked were infected by one or more viruses. The presence of Xiphinema index , the major vector of grapevine fanleaf nepovirus, was recorded from vineyards affected by yellow mosaic. 相似文献
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烟草大田期病害配方施药试验 总被引：1，自引：0，他引：1
鉴于云南烟区大田期烟草病害混合发生日趋严重,单一农药品种防效较差的状况,作者选用云南烟区几个常用农药品种,根据田间病害组成相和农药理化性质,提出了烟草配方施药方案,并进行了田间小区试验和同田对比试验。小区试验结果表明:909—B1混配剂对烟草赤星病平均防效为71.1％,对烟草蛙眼病、炭疽病、角斑病等叶斑类病害的平均防效为81.3％,对烟草野火病平均防效为80.9％。同田对比试验与小区试验结果基本相同,表明配方施药对真菌、细菌病害有较好的防治效果,尤其是909—B1明显优于其他供试农药品种。 相似文献
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黄瓜花叶病毒外壳蛋白质进入叶绿体与症状发生的关系 总被引：7，自引：0，他引：7
由感染黄瓜花叶病毒(CMV)、健康和转外壳蛋白(CP)基因的烟叶以原生质体法制备纯化的叶绿体。经SDS-PAGE电泳,银染色,比较其蛋白质图谱。用CMV外壳蛋白游离亚基制备的抗血清进行Western blotting。结果发现:1.CP存在于CMV侵染的烟叶绿体中。2.叶绿体中CP的浓度和花叶症状严重程度呈正相关;3.表达CP的转基因烟草叶绿体中未测出CP存在。根据以上结果,认为CMV侵染的烟花叶症状产生与CP进入叶绿体有直接相关性。 相似文献
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Terence W. Hill 《Pest management science》1977,8(6):625-630
Experimental fumigations of cased tobacco with methyl bromide to control the Cigarette beetle (Lasioderma serricorne) were conducted at low temperatures. Two stowages, each of 120 × 181 kg cases, were built and made gas-tight with seamless polyethylene film. Methyl bromide was introduced into each stowage at a concentration of 64 g/m3. Gas concentrations were monitored at a depth of 15 cm into the tobacco and at the centre of cases. Six cases (two open, two with folded polyethelene liners and two with heat-sealed polyethylene liners) were sampled in each stowage. Good penetration was achieved when atmospheric temperatures ranged from 6.5 to 8.5°. It is concluded, therefore, that tobacco fumigations with methyl bromide may be carried out satisfactorily in cold weather, providing that temperatures do not fall to a level at which insects become highly tolerant to the fumigant. However, amounts of fumigant reaching the centre of the heat-sealed cases were insufficient to ensure the effectiveness of such treatments in all situations. It is recommended, therefore, that the procedure of slitting polyethylene liners of heat-sealed cases before fumigation be continued. 相似文献
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