葱蒜锈病叶的红外光谱研究

[目的]采用傅里叶变换红外光谱对葱蒜锈病叶进行了研究,探讨中红外光谱在作物病害诊断中的应用潜力。[方法]用傅里叶变换红外光谱测试了葱蒜正常绿叶及锈病叶,分析其光谱差异。[结果]葱、蒜绿叶的红外光谱主要显示了多糖类物质、蛋白质、酯类振动;正常绿葱蒜叶和锈病葱蒜叶光谱在1 800～1 000 cm-1指纹范围显示了差异,与正常绿叶相比,锈病葱叶在1 640 cm-1的酰胺Ⅰ振动峰变强,在1 103 cm-1处的肩峰不明显;锈病叶的吸收强度比A1640/A1063、A1640/A1736、A1640/A2924和A1063/A2924较正常叶相应比值A1638/A1059、A1 638/A1 738、A1 638/A2 922和A1 059/A2 922变大。正常蒜叶的多糖振动峰1 056 cm-1为指纹区的最强峰,而锈病叶在1 634 cm-1处峰为指纹区的最强峰;锈病蒜叶的吸收强度比A1634/A1069、A1634/A1099、A1409/A2923和A1634/A1737较正常叶的相应比值A1627/A1056、A1627/A1104、A1411/A2920和A1 627/A1 740变大,锈病叶的A1 634/A2 923、A1 069/A2 923和A1 737/A2 923较相应正常叶的A1 627/A2 920,A1 056/A2 920,A1 740/A2 920变小。[结论]根据红外光谱差异可以区分绣病叶与正常叶,红外光谱可望发展成为作物病害检测的方法。     

水稻黑条矮缩病暴发流行原因分析——以河南开封为例

水稻黑条矮缩病最早于1963年在浙江省余姚的早稻上发现,1964-1966年在浙江、江苏和上海等地流行或局部危害,1967年后华东地区发病迅速减轻,20世纪70年代在浙江病区难以找到病株,但1991-2002年浙江杂交稻区水稻黑条矮缩病又再次流行成灾,随后发病面积下降。2006年以来在江苏、浙江、山东等稻区大面积发生,并迅速上升为当地水稻主要病害之一,给水稻生产造成了巨大的经济损失。2013-2014年,水稻黑条矮缩病在河南沿黄部分稻区严重发生。本文从稻-麦连作的耕作制度,介体灰飞虱的越冬基数大、带毒率高,田间毒源丰富、易感水稻品种多,介体灰飞虱发生高峰与秧苗敏感期高度重合等方面,分析了水稻黑条矮缩病间歇性暴发流行的原因,以期为该病科学防控提供理论依据。     

不同栽培方式下草莓灰霉病的发生动态

系统调查了不同栽培模式下由灰霉病菌引起的大棚草莓灰霉病的发生规律。结果表明,不同草莓品种章姬、红颜、丰香灰霉病的发病程度依次加重;草莓种植密度越大,发病越重;浅沟厢较深沟厢发病重;田间氮肥用量大发病重;不清除病残体地块由于其菌源基数较高发病较重;草莓连作地块发病重,连作年限越长,发病越重;通风较差的地块发病重。     

250g/L丙环唑EC防治小麦条锈病和白粉病的效果探讨

为探明250 g/L丙环唑EC对小麦条锈病和白粉病的防治效果及合理使用剂量,采用测报调查、随机区组设计和统计分析方法,开展了250 g/L丙环唑EC防治小麦条锈病和白粉病田间药效试验示范。结果表明,在春季条锈病流行期间,用250 g/L丙环唑EC 600 m L/hm2、450 m L/hm2和300 m L/hm2连续施用2次,对小麦条锈病有很好的防治效果,药后8天和18天防效均在98%以上,且各使用剂量之间防效差异不显著。对小麦白粉病亦有很好的防治效果,药后8天防效均达100%,但持效期仅10天左右,药后18天,防效显著下降,用250 g/L丙环唑EC 600 m L/hm2防治效果仅78.4%,用250 g/L丙环唑EC 450 m L/hm2及以下剂量,防治效果在41%以下。在小麦条锈病和白粉病发生不重情况下,使用最佳剂量为300~450 m L/hm2,有利于减少农药使用量和农残污染,节约防治成本。但在白粉病偏重及以上发生和条锈病混发麦地,须连续2次用250 g/L丙环唑EC 600 m L/hm2,以确保防治效果。利尔化学股份有限公司和先正达苏州作物保护有限公司生产的250 g/L丙环唑EC,用量相同防效没有差异,且国内和国外公司生产的250 g/L丙环唑EC质量没有差异。从节约防治成本考虑,最好用国内利尔化学股份有限公司生产的250 g/L丙环唑EC。     

盐碱土锈腐病拮抗菌的筛选和鉴定

[目的]对黑龙江省大庆地区盐碱土壤进行嗜(耐)盐碱菌的筛选。[方法]采用不同Na Cl浓度梯度的Sehgal-Gibbons平板筛选,利用琼脂块法获得对人参锈腐病病原菌有拮抗作用的嗜(耐)盐碱菌株,并将传统的形态学观察与现代分子生物学技术相结合对其进行鉴定。[结果]从大庆地区盐碱土壤中共分离出48株细菌,其中60.4%的菌株为耐盐菌,其余为中度嗜盐菌。所有菌株的耐碱能力在pH 8.0~11.0,其中64.6%的菌株耐碱能力高达pH 11.0,除2株为嗜碱菌,其余均为耐碱菌。人参锈腐病毁灭柱孢菌R2拮抗性筛选获得3株菌,经形态学、生理生化特征及16SrRNA基因序列的系统发育分析,确定3株菌分别为Halomonas elongata、Halomonas xianhensis和Oceanobacillus iheyensis。[结论]从盐碱土中获得3株对人参锈腐病有拮抗作用的嗜(耐)盐碱菌,并进行了鉴定。     

Application of Statistical Tools for Data Analysis and Interpretation in Rice Plant Pathology

There has been a significant advancement in the application of statistical tools in plant pathology during the past four decades. These tools include multivariate analysis of disease dynamics involving principal component analysis, cluster analysis, factor analysis, pattern analysis, discriminant analysis, multivariate analysis of variance, correspondence analysis, canonical correlation analysis, redundancy analysis, genetic diversity analysis, and stability analysis, which involve in joint regression, additive main effects and multiplicative interactions, and genotype-by-environment interaction biplot analysis. The advanced statistical tools, such as non-parametric analysis of disease association, meta-analysis, Bayesian analysis, and decision theory, take an important place in analysis of disease dynamics. Disease forecasting methods by simulation models for plant diseases have a great potentiality in practical disease control strategies. Common mathematical tools such as monomolecular, exponential, logistic, Gompertz and linked differential equations take an important place in growth curve analysis of disease epidemics. The highly informative means of displaying a range of numerical data through construction of box and whisker plots has been suggested. The probable applications of recent advanced tools of linear and non-linear mixed models like the linear mixed model, generalized linear model, and generalized linear mixed models have been presented. The most recent technologies such as micro-array analysis, though cost effective, provide estimates of gene expressions for thousands of genes simultaneously and need attention by the molecular biologists. Some of these advanced tools can be well applied in different branches of rice research, including crop improvement, crop production, crop protection, social sciences as well as agricultural engineering. The rice research scientists should take advantage of these new opportunities adequately in adoption of the new highly potential advanced technologies while planning experimental designs, data collection, analysis and interpretation of their research data sets.     

Large scale biotic damage impacts on forest ecosystem services

Insect outbreaks are natural phenomena that play a critical role in the development, senescence, and rebirth of forests. However, the damage caused by large-scale epidemics can have landscape scale consequences that are often poorly understood. The recent mountain pine beetle (MPB) outbreak in Canada has impacted a record >18.5 million hectares of pine forests, placing forest values at risk and significantly impacting forest-dependent communities within the region. To assess this impact, an ecosystem service-based approach was applied. Based on land cover information and monitoring data, four ecosystem services were assessed and mapped: merchantable timber, water provisioning, aboveground carbon storage, and vegetation diversity (supporting habitat). Timber is the most impacted provisioning ecosystem service followed by water provisioning, with peak stream flow in affected watersheds being positively related to mortality percent. Effects on carbon storage are substantial, with 20% of total timber aboveground carbon in dead pine trees. These effects may be mitigated, however, by the growth response of residual live trees and forest regeneration. The potential vegetation diversity showed a positive response to MPB-caused tree mortality. The results of our study may help with setting management priorities in response to large-scale biotic damage in forests in British Columbia and elsewhere.     

小麦条锈菌有性生殖与毒性变异的研究进展

小麦条锈病是由条形柄锈菌小麦专化型Puccinia striiformis f.sp.tritici Erikss.et Henn.引起的、最具毁灭性的小麦真菌病害之一,在全世界小麦种植的国家或地区均有发生,其流行常常导致小麦严重的产量损失。利用抗病品种是防治小麦条锈病最为经济、有效的措施。然而,由于病原菌毒性变异不断产生新小种,频繁导致品种抗病性"丧失",继而引发病害流行成灾。小麦条锈菌的有性阶段过去一直未被发现,有性生殖与条锈菌变异及其在病害发生中的作用研究一直处于空白状态。近年来,随着小麦条锈菌转主寄主的发现,国内外学者开展了相关的研究工作,取得了一系列重要的研究进展。本文综述了小麦条锈病的发生症状、病菌的生物学特性、转主寄主、有性生殖与条锈菌毒性变异、转主寄主在条锈病发生中的作用、影响有性生殖发生的因素等方面的最新进展,并展望了深入开展小麦条锈菌有性生殖的研究思路。     

种子带毒率及有翅蚜降落量对SMV流行的影响

大豆田主要迁飞降落的蚜虫有大豆蚜、棉蚜、玉米蚜、桃蚜、禾谷缢管蚜、豆蚜等,而大豆蚜的数量占绝对优势。当有翅蚜迁飞降落量大,同时田间病株率高时,SMV日侵染率高,最高达49.57%。田间有翅蚜发生和迁飞降落高峰一般在7月份,此时的迁飞降落蚜量和SMV的种子带毒率决定病害流行的程度。0.5%种子带毒率显著推迟SMV流行的时期。田间有翅蚜发生和飞翔高峰期推迟到8月份,0.2%和0.1%种子带毒率可控制SMV的流行为害。     

Patterns and Management of Crop Multiple Pathosystems

The study of multiple pathosystems has played a central role in the development of botanical epidemiology, leading to a number of approaches and concepts. Multiple pathosystems are facts, which are experienced by many non-cultivated, or cultivated, plant communities. The shapes and composition of multiple pathosystems vary in space and time because of their inherent structure of relationships, and also in response to management. Examples of variation in multiple pathosystems are given, of groundnut in Côte d’Ivoire, of wheat in Brittany, and of upland rice in northern Laos. Variation in the yield-reducing effects of multiple pathosystems is discussed, including interactions among disease elements, relationships with attainable performances, and linkages with production situations. Progress has been achieved in understanding the links between injury profiles, production situations, and attainable performances. Questions about the functioning and consequences of multiple pathosystems are central to defining the scientific bases for, the design of, and the implementing of IPM. The complexity of multiple pathosystems, however, remains a deterrent, not a challenge, to many plant pathologists. Progress achieved in designing production systems for hardy wheat in France, however, is very promising, because of the multidisciplinary science it involves, and because of the promise to deliver it carries. The concepts of epidemiological guilds and of guilds of harmful agents are offered as perspectives to address and manage syndromes of production and syndromes of disease.