襄阳地区小麦条锈菌越冬潜伏菌源量与病情的关系研究

 在小麦条锈病菌(Puccinia striiformis f. sp. tritici,PST)越冬区的湖北襄阳、宜城和枣阳3个地区同一时间定点(GPS定位)采样,应用双重real-time PCR定量测定方法进行潜育侵染测定,并于春季在相应取样点进行病情调查。取样区域按照镇/区划分成不同的区域。每个区域的分子病情指数(MDI)和病情指数(DI)由该区域内所有样品和调查点数据取平均值得到。由MDI转换成风险指数(RI),并做RI与春季病情指数的相关性分析。同时,也通过坐标数据进行了空间分析。结果显示,PST潜伏侵染量与春季病情呈显著相关,并且两者均与其分布区域距汉江水系的距离相关。     

应用real-time PCR评价三种杀菌剂对小麦条锈病的防治效果

为更加精确有效地评估杀菌剂对小麦条锈病的防效,本研究利用real-time PCR检测潜育阶段的分子病情指数(molecular disease index,M DI)并结合田间病情分析,对三种杀菌剂的防效进行评价。春季返青后在品种铭贤169和京0045试验小区的诱发中心接种小麦条锈菌夏孢子,待充分发病后将其铲除。设置播种前2%立克秀拌种,接种后21和28 d分别喷施25%阿米西达和30%苯甲-丙环唑1 500倍液三种处理。发病后调查不同处理的普遍率和严重度,计算病情指数和AUDPC。结果表明,阿米西达和苯甲-丙环唑对小麦条锈病具有良好的防效且能够明显抑制发病中心的扩展,而经立克秀拌种对该病害的防治效果和发病中心扩展的抑制作用均不理想。对京0045于发病中心接种后24和33 d采样,经双重real-time PCR定量检测,计算MDI。结果显示潜育检测获得的M DI与AUDPC之间均具有极显著的相关性;阿米西达和苯甲-丙环唑对潜育期小麦条锈菌的扩展具有明显的持续抑制作用,而立克秀拌种仅对小麦条锈菌潜伏初期的扩展表现出一定的抑制作用。     

应用real-time PCR定量检测小麦条锈菌潜伏侵染量方法的建立

 小麦条锈病是我国小麦主要病害之一。快速、及时地诊断与定量监测处于潜育状态下的病叶,对准确估计越冬、越夏后的病情,制定正确的防治方案具有重要的意义。根据小麦条锈菌Puccinia striiformis的β-tubilin基因序列设计对该病原菌的种具有特异性的引物betaf/betar,并分别在普通PCR和real-time PCR扩增时对该引物的特异性和灵敏性进行了测定。结果表明该引物对小麦条锈菌特异性高,可稳定扩增出243 bp的目标条带。Real-time PCR的灵敏度为普通PCR的100倍。应用此特异性引物,建立了real-time PCR测定系统,定量测定了条锈菌在小麦叶片接种后组织内的DNA随时间的变化。结果表明,在接种后12 h,可在小麦叶片内检测到条锈菌,且条锈菌在小麦叶片内潜育期间随时间呈指数增长。接种第6 d后叶片内的菌量有明显的增加。建立的小麦条锈菌的real-time PCR早期定量测定方法,为及时、快速监测小麦条锈病在潜育期间的发病规律以及为该病的预测、防治提供依据。     

乌鲁木齐大气总悬浮颗粒物（TSP）离子化学组分及影响因素

利用2009年乌鲁木齐4个大气总悬浮颗粒物（TSP）观测站点资料,采用离子色谱仪分析了TSP中水溶性离子成分。结果表明：① 2009年乌鲁木齐市区3站总离子浓度为151.28 μg/m³,白杨沟为40.83 μg/m³。4站NO₃^-/SO4^2-比值较小,表明乌鲁木齐大气污染主要来自于固定污染源。② 2009年乌鲁木齐4站TSP中SO₄^2-、Ca²⁺、NO₃^-和NH₄⁺的浓度高于其他各离子,各站离子浓度有明显的季节变化特征,采暖期各离子浓度明显增加,SO₄^2-、NO₃^-增幅最大。③ 对各主要离子进行相关性分析,得到NH₄⁺与SO₄^2-的相关系数为0.828,与NO₃^-的相关系数为0.659,说明铵盐化合物主要以硫酸铵和硝酸铵的形式存在;SO₄^2-与NO₃^-的相关性很大,相关系数为0.973,表明二者主要来自二氧化硫和氮氧化物,排放方式与在大气中的传输途径较一致;地壳元素Ca²⁺和Mg²⁺有很好的相关性,相关系数是0.914,表明二者来源相似,可能主要来自风沙土壤尘、道路尘和建筑尘。     

蜡质芽孢杆菌R2防治水稻纹枯病研究

 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%。     

小麦抗条锈反应中活性氧及细胞质钙离子的作用

 为探讨活性氧和细胞质钙离子在小麦抗条锈病反应中的作用,以小麦品种洛夫林13与具有不同致病力的单孢锈菌CY29、CY25的互作体系为平台,对锈菌侵染后小麦叶片中活性氧(ROS)积累、保护酶系(SOD、CAT和APX)活性变化动态、细胞质膜的透性改变及细胞质钙离子浓度变化做了研究。结果表明,不亲和锈菌CY25侵染可引起小麦叶片内2次ROS的爆发,第1次出现在接种后前期(接种后第2天),强度较小,第2次出现在接种后期(接种后第5天),强度较大;亲和锈菌CY29侵染只引起1次ROS爆发,出现在接种后期(接种后第5和第6天之间),但强度极大。过敏性坏死反应HR只出现在不亲和互作小麦叶片上前期ROS爆发之后,表明前期ROS爆发与HR的产生有关。伴随着后期小麦叶片中强度极高的ROS的爆发,叶片细胞原生质膜遭到了破坏,细胞内物质外渗,细胞不久便死亡,表明高强度的ROS爆发会导致细胞死亡。根据不同互作体系ROS爆发时期SOD、CAT和APX等保护酶的活性变化分析,不亲和互作体系前期强度较小的ROS爆发主要成分是H₂O₂,后期强度较高的ROS爆发主要成分是O₂^-_·和H₂O₂;亲和互作体系强度极高的ROS爆发主要成分是O₂^-_·和H₂O₂。由此说明H₂O₂是引起小麦抗病反应HR发生的因素,而O₂^-_·则是引起细胞死亡的因素。细胞质钙离子浓度变化研究表明,HR的发生与细胞质钙离子浓度增加相关。细胞质钙离子浓度的降低推迟了HR的发生,这说明小麦叶片细胞内细胞质钙离子浓度的增加是HR的必要条件,同时也说明Ca²⁺是植物HR的胞内第二信使参与植物抗病防卫反应。     

西北地区小麦生产环境风险时空特征

利用CROPWAT模型和生命周期评价(LCA)方法，对西北地区2005—2020年小麦生产的投入、环境风险和水分需求进行分析和评价。结果表明：西北地区氮、磷、钾平均肥料投入量分别为238、142、62.5 kg·hm^-2;农药、柴油、种子、人工的投入量分别为4.35 kg·hm^-2、1.26 L·hm^-2、305 kg·hm^-2、771 h·hm^-2。西北地区平均小麦产量3.68 t·hm^-2,排放温室气体3 589 CO₂-eqkg·hm^-2,土壤酸化潜值87.0 SO₂-eqkg·hm^-2,消耗能量3.3×10⁸ J·hm^-2。肥料投入对温室气体排放和能量消耗的贡献最大，分别达到86.5%和77.8%;农作阶段在土壤酸化潜值中贡献率最高，占比达90%以上。西北地区小麦生产平均需水量为331 mm,平均灌溉需水量为227 m...     

铵态氮和硝态氮对香蕉枯萎病发生的比较研究

 为寻找降低香蕉枯萎病发生的防治措施,通过室内盆栽接种试验,研究了铵态氮(NH₄⁺-N)和硝态氮(NO₃^--N)对香蕉枯萎病发生及其植株叶绿素含量、气体交换参数、病原菌在植物体内的数量分布和植物钙(Ca)、镁(Mg)、铁(Fe)、钼(Mo)、可溶性糖和木质素含量的效应。结果表明:不接种病原菌的条件下,不同氮素处理对香蕉幼苗生长影响无差异;接菌情况下,与NH₄⁺-N处理相比,NO₃^--N处理显著降低植株各器官的病原菌数量、发病率和发病严重程度。病原菌侵染后,不同氮素处理下植株光合作用均显著下降:NO₃^--N处理香蕉苗保持比NH₄⁺-N处理更高的光合速率;病原菌侵染后NH₄⁺-N处理的植株Ca、Mg、Fe和Mo含量相对于侵染前没有显著差异,但NO₃^--N处理下此4种元素含量均显著升高。病原菌侵染后的植株叶片可溶性糖含量在不同氮素处理中都没有显著变化,但在根系中,NO₃^--N处理的侵染植株可溶性糖含量显著降低。与此同时,病原菌侵染后,木质素含量在NH₄⁺-N处理植株中变化不显著,但其含量在NO₃^--N处理侵染后显著上升。综上所述,NO₃^--N处理可增加植株抗病相关矿质元素的吸收,诱导香蕉苗木质素形成,使其木质化程度增加,从而维持较高的光合作用,保持较高的抗病水平。     

新疆昌吉州东部平原区地下水水文地球化学演化分析

为探究新疆昌吉州东部平原区地下水水质演化过程，采用数理统计、Piper三线图、Gibbs图和离子比法对昌吉州东部平原区2016年63组地下水水质取样点及54组2012—2015年地下水水质监测数据进行分析。结果表明：昌吉州东部平原区2012年地下水阳离子平均含量总体为Ca²⁺>K⁺+Na⁺>Mg²⁺，阴离子平均含量总体为HCO^3->SO₄^2->Cl^-；从2013年开始，SO₄^2-逐渐增大，Ca²⁺逐渐减小；到2016年阳离子平均含量总体为Ca²⁺>K⁺+Na⁺>Mg²⁺，阴离子平均含量总体为HCO₃^->SO₄^2->Cl^-。水化学类型由2012年HCO₃—Ca·Mg（Ca·Na、Ca·Na·Mg）型向2016年HCO₃·SO₄—Ca·Na·Mg（Ca·Mg、Ca·Na）演化，这主要与含水介质的风化作用和蒸发浓缩作用有关，而蒸发浓缩作用更加体现在承压水区的上部潜水中。地下水中Na⁺、K⁺、Cl^-主要来自岩盐的溶解；Ca²⁺、Mg²⁺主要来自蒸发岩溶解；SO₄^2-主要来自石膏（CaSO₄·2H₂O）和芒硝（Na₂SO₄·10H₂O）的溶解。Cl^-、SO₄^2-除来自岩盐的溶解外，还受到人类活动的影响。     

玛纳斯河流域绿洲土壤春季盐渍化研究

运用经典统计学和冗余分析方法,对玛纳斯河流域绿洲土壤全盐量（TS）、pH、电导率（EC）、钠吸附比（SAR）和盐分离子组成的空间分布特征进行了分析。结果表明：土壤全盐量呈现明显的底聚特征,各层土壤全盐量均值在5.80~9.02 g•kg^-1,表现为轻度至中度盐化;各层土壤中,pH在8.2~8.4、EC在0.70~1.38 mS•cm^-1、SAR在0.25~0.64,未出现碱化现象。冗余分析表明：不同层次土壤中,Ca ²⁺与SO ₄^2-、Na⁺与SO₄^2-保持较好的关联性。TS的空间分布,在 0 ~70 cm 全剖面上主要受控于Na^+、SO₄^2-、Ca ²⁺和Mg ²⁺;分层与全剖面的情况略有不同,但Na⁺、SO₄^2-在各个土层仍为最主要的控制离子。EC在全剖面上的空间分布受控于 Na⁺、SO₄^2-;50 ~70 cm 土层主要受Na⁺与Cl^-的控制,其他土层与全剖面相同。 pH受控于CO₃^2-;除0~10 cm土层受HCO^-₃影响外,其他土层与全剖面相同。SAR在全剖面的空间分布受环境因子的影响较小,除50~70 cm土层受Cl^-因子的制约外,0~50 cm土层未表现出明显的控制因子。     

辽宁省药用植物白鲜病害种类调查及病原鉴定

白鲜为我国传统药用植物,具有较高的经济价值和药用价值,近年来在辽宁省大面积人工种植。为明确白鲜主要病害种类及发生危害情况,2018年-2020年生长季在辽宁省本溪、清原和西丰等主要种植地区进行了病害系统调查。调查和鉴定结果发现,危害白鲜生产的主要病害有5种,分别为由Phoma dictamnicola引起的茎点霉叶斑病、由Paracercospora dictamnicola引起的灰斑病、由Rhizoctonia solani引起的立枯病、由Fusarium oxysporum引起的根腐病和由Meloidogyne hapla引起的根结线虫病,并对各病害症状进行了详细描述。其中茎点霉叶斑病、灰斑病和立枯病分布广且危害较重,病害种类和发病情况地区间差异较大。立枯病主要发生在一年生育苗田,病株率一般为0.6%～19.0%,灰斑病和茎点霉叶斑病主要发生在生产田,病株率分别为38.2%～100.0%和17.6%～99.0%。研究结果将为白鲜病害的准确识别诊断及综合防控策略制定提供科学依据。     

百合病毒病的发生与症状类型

百合病毒病症状类型可归纳为7种类型,轻花叶型(Mm),重花叶型(Sm),矮化型(Stu),丛簇矮化型(Rstu)。黄化矮化型(Ys),扁茎簇叶型(Fsbl),花变叶型(Phy),其中轻花叶型和重花叶型发生普遍,花变叶型出现较少。病害发生的轻重与种球种龄有关,种龄越大,发病越重。前茬种植百合的地块较种植小麦的地块发病重,低洼积水地发病重。不同百合品种对病毒病的抗性有差异。     

Development of weather-based prediction models for leaf rust in wheat in the Indo-Gangetic plains of India

Weather based prediction models for leaf rust were developed using disease severity and weather data recorded at four locations viz. Ludhiana, Kanpur, Faizabad and Sabour of the All India Wheat and Barley Improvement Project. Weeks 7–9 of the crop growing season at Ludhiana, Faizabad and Sabour and weeks 10–12 at Kanpur were identified as critical periods for relating weather variables to disease. Highly significant correlation coefficients were found between disease severity and a greater number of weather variables in these critical 3-week periods than at other times. The correlation coefficients were greatest for the Humid Thermal Ratio (HTR), Maximum Temperature (MXT) and Special Humid Thermal Ratio (SHTR), and these three weather variables were selected as predictor variables. Linear regressions with these predictor variables (individually) during the critical periods, and a multiple regression with MXT and relative humidity (RH), serve as four disease prediction models, with sufficient lead-time to take control measures. Validation of these prediction models with independent disease severity data showed that the regression equation with MXT (Model-1) was the best among the prediction models, with four out of six simulations matching observed disease severity classes and also having lowest residual sum of squares (SSE) value of 2727. Models 4 (multiple regression), 2 (HTR) and 3 (SHTR) with SSE values of 2881, 3092 and 3732, respectively are in order of decreasing accuracy of prediction. The model using MXT can be used to predict the disease severity in the Indo-Gangetic Plains and provide the basis for efficient disease control.     

我国甘蔗主要杂交亲本黄叶病病原鉴定及田间发病率

甘蔗黄叶病是一种发生普遍、危害严重的病毒病害,选育抗病品种是控制该病发生与蔓延的有效措施.利用逆转录-聚合酶链反应(RT-PCR)、组织印迹杂交免疫测定(TBIA)和抗原直接包被酶联免疫吸附(DAC-ELISA)方法对我国43份甘蔗主要杂交亲本黄叶病病原(Sugarcane yellow leaf virus,SCYLV)进行鉴定,并调查SCYLV田间自然侵染条件下甘蔗黄叶病发病率.已明确36份亲本材料感染或未感染SCYLV,其中32份鉴定结果为阳性,品种(系)感病率达88.9％.甘蔗植株田间自然发病率可分为无发病、发病率低、中等和高4个等级,方差分析表明,各等级间的植株发病率差异达极显著水平(P＜0.01).从美国引进的多数CP和HoCP系列亲本发病率较高,而多数崖城和新台糖系列亲本材料的发病率较低,可作为甘蔗抗黄叶病杂交亲本.     

A time series analysis of brown eye spot progress in conventional and organic coffee production systems

Brown eye spot (BES), caused by Cercospora coffeicola, is an important coffee disease in Brazil. Losses related to this disease have increased over the last few years. Because the factors associated with the disease dynamics are not fully understood, it is important to gather information about this in different cropping systems. BES epidemics were compared from three production systems: organic (OS), organic under shade (OSS) and conventional under full sun (CS). This study was conducted in Ervália‐MG, Brazil, from November 2004 to October 2008. Disease progress was modelled with all 4 years of data in a time series analysis. Disease intensity (severity (SEV) and incidence (INC)), leaf setting (LS) and leaf fall (LF) were assessed on a monthly basis. The highest values for SEV, INC, LF, LS, as well as a larger area under the disease progress curve and maximum disease occurred in CS and in the upper branches, whereas the lowest values for all variables occurred in OSS and in the lower branches. The highest values occurred for SEV and INC from May to July, for LF from July to September, and for LS from October to January. The disease progress was successfully modelled via a time series analysis. The seasonal behaviour of disease progress for all years and production systems was modelled with a nonlinear sinusoidal model with autoregressive moving average (ARMA) errors. Estimated parameters were generated which could be useful for comparative epidemiology, and it was shown that shade could be used in the field for BES management.     

Genotype × environment Effects on Severity of Cassava Bacterial Blight Disease caused by Xanthomonas axonopodis pv. manihotis

Nine cassava genotypes were grown for three years at six sites representing three agro-ecological zones in Nigeria to study their reaction to cassava bacterial blight (CBB), investigate genotype × environment (G × E) interaction patterns for their reaction to CBB, and to identify genotypes with stability to the disease, using the additive main effects and multiplicative interaction (AMMI) statistical model. Environments, genotypes and G × E interactions accounted for 71.8%, 12.0% and 16.2% of the treatment sums of squares (SS), and were highly significant (P<0.0001) for the disease, indicating that genotypes responded differentially to CBB infection across environments. Clones 30555, 91934, U/41044, and 4(2)1425 showed the least CBB disease ratings. Other clones showed erratic and fluctuating reactions to CBB from environment to environment and were thus considered unstable to the disease. CBB was most severe in 1989 (with a mean score of 2.46) and least so in 1990 (with a score of 2.06). The sites with the most disease were Ibadan, Ilorin and Ubiaja (1989), Ibadan and Ubiaja (1990) and Mokwa (1991). Because of the favourable conditions for disease development at those sites, they could be appropriate for screening cassava genotypes for CBB resistance. The AMMI model selected AMMI1 as the best predictor for CBB because it had the smallest actual root mean square prediction difference (0.37646), and explained 90.7% of the G × E interaction for CBB. The AMMI model was successful in selecting the genotypes 30555, U/41044 and 4(2)1425 and the environments Ibadan 1989, Ilorin 1989 and Onne 1990 with stability of reaction to the disease.     

Epidemic dynamics and patterns of plant diseases

ABSTRACT The general Kermack and McKendrick epidemic model (K&M) is derived with an appropriate terminology for plant diseases. The epidemic dynamics and patterns of special cases of the K&M model, such as the Vanderplank differential-delay equation; the compartmental healthy (H), latent (L), infectious (S), and postinfectious (R) model; and the K&M model with a delay-gamma-distributed sporulation curve were compared. The characteristics of the disease cycle are summarized by the basic reproductive number, R(0), and the normalized sporulation curve, i(tau). We show how R(0) and the normalized sporulation curve can be calculated from data in the literature. There are equivalences in the values of the basic reproductive number, R(0), the epidemic threshold, and the final disease level across the different models.However, they differ in expressions for the initial disease rate, r, and the initial infection, Q, because the values depend on the sporulation curve. Expressions for r and Q were obtained for each model and can be used to approximate the epidemic curve by the logistic equation.     

江西甘蔗花叶病病原的分子鉴定

 Sugarcane mosaic disease, caused by Sugarcane mosaic virus (SCMV), Sorghum mosaic virus (SrMV), Maize dwarf mosaic virus (MDMV) or Johnsongrass mosaic virus (JGMV) in Potyvirus, is one of the most important viral diseases of sugarcane. In the study, four primer pairs specific to SCMV, SrMV, MDMV and JGMV, respectively, were designed and used to detect 29 sugarcane leaf mosaic samples collected from 9 locations in Jiangxi province. The representative RT-PCR products were sequenced. The results showed that 22 samples were infected by SCMV, three by SrMV, and four were mix-infected by SCMV and SrMV. MDMV or JGMV were not identified in all samples. The result indicates that SCMV is the major pathogen of sugarcane mosaic disease in Jiangxi province, and SrMV is also a pathogen for the disease.     

AM真菌诱导的番茄信号物质及其对根结线虫的 抑制 效应

丛枝菌根(AM)真菌能诱导植物合成一些信号物质,如茉莉酸(JA)、水杨酸(SA)、一氧化氮(NO)、H2O2等,这些信号在AM真菌与植物识别、共生体建立和激活植物防御系统过程中发挥着重要作用[1].     

宁夏设施番茄病毒病病原鉴定

正番茄病毒病是番茄(Solanum lycopersicum)安全生产的主要限制因素,感染番茄作物的病毒种类高达136 种~[1]。小RNA测序和组装技术(small RNA sequencing and assembly, sRSA)已用于不同物种的病毒检测~[2]。Xu等~[2]对采自我国的170个番茄样本进行小RNA深度测序分析,鉴定出22种病毒。其采样地点未包括宁夏回族自治区。宁夏是我国重要的设施番茄生产基地, 2011 年宁夏银川市