宾川地区烟草病毒病病原种类及其侵染循环初探

 对宾川烟草病区病毒病进行调查采样,应用病毒分离提纯技术、电子显微镜技术开展鉴定研究,得出:(1)宾川烟草病毒病原以CMV,PVY,TMV,TEV发生较为普遍,且危害严重,此外有PVX,一种球形病毒〔可能是番茄斑萎病毒(TSWV)〕也有零星发生,以症状来看,还有环斑、曲叶、丛枝、条纹等类型,但未分离到明显病原;(2)病毒病病原的分布在宾川主栽烤烟品种上没有明显的差异,而分布与生态类型有关,年度间种群分布相对稳定;(3)探明烟苗期烟苗带毒率和带毒量是宾川烟草中后期病毒流行的决定性因素;(4)探明了病毒、寄主、媒介(蚜虫)三者之间的关系及其烟草病毒病的侵染循环。     

辐射松根朽病与林龄和环境条件关系的数量化分析

对新西兰辐射松根朽病（Ａｒｍｉｌｌａｒｉａｓｐｐ．）的发病程度与林令和环境条件的关系进行了数量化分析。结果表明影响该病发生的主要因素有：年降雨量、地形、土壤类型、前作以及它们之间的互作关系。以此建立的多无线性回归模型为：＝－４．３＋５．４Ｒ２＋１２．４ｓ４＋７．８ｐ１＋６．７ｐ２＋２９Ｌ２＋３１．１Ｒ２ｐ１Ｌ２．根据这一模型可预测新西兰境内任一给定的条件下根朽病的可能侵染水平,以供造林设计和防治时参考。     

晋中盆地麦蚜发生为害程度及原因分析

晋中盆地麦蚜发生为害高峰常出现于小麦孕穗到灌浆期,大发生年发生高峰可提前至拔节期。从1998～2003年连续6年的系统观察调查得出,遇暖冬及早春温暖干旱气候,麦蚜呈现早发生或大发生;如遇冬春低温多雨,尤且是1～2月份极端温度低于-20℃,时间长达15d时,对麦蚜发生形成明显抑制。另外,蚜虫发生程度与天敌数量关系密切,小麦播种面积与蚜虫发生总量呈正相关关系。     

茄链格孢菌侵染马铃薯叶片过程的细胞学观察

采用光学显微镜和电镜技术系统研究了茄链格孢菌对马铃薯叶片的侵染过程及超微结构特征。结果表明：接种2 h后,分生孢子开始萌发,分生孢子各个位置都可萌发产生芽管|接种6 h后,菌丝顶端出现附着孢|接种8 h后,菌丝从细胞间凹陷处直接侵入感病品种东农303叶片表皮细胞内|接种24 h后,受侵染寄主细胞中的菌丝向相邻细胞扩展蔓延,感病品种细胞内含物及各类细胞器基本完全消解。在抗病品种克新1号上,茄链格孢菌的侵染情况与感病品种基本一致,但发生时间明显较感病品种推迟,寄主细胞内的菌丝数量明显少于感病品种|并且在接种24 h后出现细胞壁加厚的防卫反应,在感病品种上没有观察到防卫反应现象。说明抗病品种对茄链格孢菌具有一定的抗侵入和抗扩展能力。     

Light and scanning electron microscopy studies on the infection process of melon leaves by Colletotrichum lagenarium

Colletotrichum lagenarium is the casual agent of anthracnose disease of melons. Light and scanning electron microscopy were used to observe the infection process of C. lagenarium on the leaves of two melon cultivars differing in susceptibility. On both cultivars conidia began germinating 12 h after inoculation (hai), forming appressoria directly or at the tips of germ-tubes. By 48 hai appressoria had melanised and direct penetration of host tissue had begun. On the susceptible cultivar, infection vesicles formed within 72 hai and developed thick, knotted primary hyphae within epidermal cells. By 96 hai C. lagenarium produced highly branched secondary hyphae that invaded underlying mesophyll cells. After 96 hai, light brown lesions appeared on the leaves, coincident with cell necrosis and invasion by secondary hyphae. While appressoria formed more quickly on the resistant cultivar, fewer germinated to develop biotrophic primary or invasive necrotrophic secondary hyphae than on the susceptible cultivar. These results confirm that C. lagenarium is a hemibiotrophic pathogen, and that resistance in melons restricts colonisation by inhibiting the development of necrotrophic secondary hyphae.     

芜菁花叶病毒对油菜的侵染性和在体内的分布运转规律

芜菁花叶病毒在油菜不同生育阶段的侵染性有很大差异,以苗期最易被侵染,而成株期抗侵染能力很强。随着植株生育进程,病毒含量由低到高,并分布于各器官。病毒的增殖和运转与植株体内营养物质的积累和运输密切相关。病毒在植株体内的垂直分布情况,随着植株的生长发育,病毒有由下向上输送的趋势。根据病毒的侵染、增殖和运转规律,对防治工作有一定指导意义。     

闽清并殖对终末宿主的感染性试验及并殖吸虫对人体致病性分型的讨论

探讨闽清并殖对人体的致病性。将闽清并殖新鲜囊蚴多次分别感染猫科、犬科和啮齿科的家猫、家狗及大鼠、小鼠、豚鼠。结果 ,只在猫、狗粪便中检及虫卵并在肺脏检及成虫 ,而鼠类未获感染。结合对已知并殖吸虫宿主的选择性的分析 ,发现对猫狗感染而对鼠类不适宜的虫种通常对人体致病 ,相反 ,对鼠类适宜而猫狗不适宜的虫种对人体大多不致病或致病力较弱 ,表明闽清并殖可能类似斯氏并殖对人体引起游走性皮下结节的病变     

AN INFECTED HIP PROSTHESIS IN A DOG DIAGNOSED WITH A 99mTC-CIPROFLOXACIN (INFECTON) SCAN

This case report describes the use of the 99mTc-labeled radiopharmaceutical ciprofloxacin (Infecton) in a case of hip prosthesis loosening in a dog. Serial planar radiographs were not conclusive, and culture of the synovial fluid was negative. Antibiotic treatment did not result in improvement of the lameness. Scintigraphy was performed with 99-Tc-Infecton, a tracer claimed to be specific for infection. Antibiotic treatment was interrupted 6 weeks prior to the examination. Planar and tomographic images at 3 h and at 24 h postinjection showed increased activity along the acetabulum and the proximal femoral bone surrounding the femoral prosthesis, indicating focal infection. Bacteriology performed after removal of the implant revealed Pseudomonas aeruginosa.     

卵孢白僵菌感染草地蛴螬的研究

从湖南南山牧场草地上自然罹病的蛴螬虫体上分离出一株卵孢白僵菌。在室内和野外人工草地进行蛴螬活虫感染试验，结果表明，在室内用卵孢白僵菌孢子液感染蛴螬活虫，30天内蛴螬感染率达64．6─92．1％；野外草地试验，用卵孢白僵菌制成菌剂拌少量细土撤于地表，20天内，蛴螬感染率为70％以上。     

昆明地区紫薇白粉病研究——Ⅱ.病原菌的分类侵染循环及病害的发生发展规律

在紫薇上,有3种白粉菌寄生——Uncinulliella australiana,Erysiphe lagerstroemiae和Phyllactinia corylea经研究,在昆明地区紫薇上的白粉菌应为Uncinulliella australiana,这与雅安地区所发生的紫薇白粉菌同属一种。菌丝体在紫薇芽鳞下越冬,春天来临或给予合适的条件,菌丝体便开始发育蔓延,对紫薇造成初侵染。分生孢子的散布受降水、温度相对湿度及风速的影响。降水明显对分生孢子散布不利。分生孢子散布具有明显的昼夜变化节律。在一年中,紫薇白粉病在春季开始发生,雨季(6月到9月)达到高峰,在晚秋停止了发展。