水稻白叶枯病杂草带菌传病的初步研究

 水稻白叶枯病由越冬带菌杂草的传病,是防治上的一个关键问题。为了探讨江苏省扬州地区杂草带菌和越冬后的传病作用,作者于1979~1983年作了这项研究,结果如下.     

水稻白叶枯病和条斑病的田间诊断和鉴别

白叶枯病(Xanthomonas oryzae)和条斑病(Xanthomonas oryzicola)是水稻上的两种重要细菌病害。这两种细菌性病害都可以由稻种传播。稻种非但可以带菌,并且可以传病。为了防止病区的扩大和新病区的出现,加强检疫工作是非常重要的。 检验水稻白叶枯病和条斑病,可分室内检验和田间检验。室内检验主要是确定稻种是否带菌和带菌的程度,可以采用种植检验和噬菌体检验的方法,以噬菌体检验更为可靠。室内检验需要一定的设备,工作量较大,同时目前所用的室内检验方法是否适用于带菌量极低的稻种,还有待在生产实践中考验。田间检验就是通过病害的普查,了解病害发生情况,确定无病田和无病区。这样非但可以解决当地的留种和换种的问题,并且为无病稻种的调运提供依     

玉米丝黑穗病菌侵染条件与栽培防病措施的研究

玉米丝黑穗病菌侵染寄主的适宜土壤温度范围为20～30℃,最高限点为35℃,最低为10℃左右。播种期与发病关系决定于种子发芽、幼苗生长速度与病菌侵染机会的多少。在吉林省的气象条件下,适期播种发病率高,早播和晚播的病株率较低。催芽播种和育苗移栽能减轻为害。种子带菌虽可传病,但侵染率不高。土壤带菌是主要传病途径。厚垣孢子在土壤中可存活三年。土壤微生物的拮抗作用是病菌丧失致病力的原因之一。此外,植物幼芽与幼根的渗出物促进厚垣孢子萌发,如遇不到寄主则丧失生命力。实行三年以上轮作及连续拔除病株是有效的栽培防病措施。     

大豆疫病种子传病研究简报

大豆疫病种子传病研究简报周肇蕙严进（农业部植物检疫实验所北京１０００２９）大豆疫病种子带菌传病是国际上长期没有澄清的问题。作者在种子带菌研究的基础上进行了种子传病的试验研究,现在种子传病研究已获得成功,简报如下。试验方法采取病种子直播和健康种子播于病...     

稻曲病种子传病的研究

据前人报道,稻曲病粒上附有大量厚垣孢子但不能作为初侵染源,并证明该病既不是种子引起的病害,也不是种子侵染而发生的病害,认为目前推广种子处理缺乏科学根据。本研究结果表明:从种子带菌量、越冬厚垣孢子萌发力、人工接种、直接播种试验,初步认为病穗种子是可以传病的,种子消毒仍有必要。     

广东水稻橙叶病病原(MLO)的越冬

研究结果表明,广东水稻橙叶病病原(MLO)的传染介体和越冬介体昆虫只有电光叶蝉(Recilia dorsalis)一种,但其卵不传递该病原到子代若虫,越冬寄主植物只有水稻的再生稻株和落粒自生稻株。在茂名病区的冬、春期间电光叶蝉的带菌虫和带菌再生稻及感病落粒自生稻始终存在,其带菌率分别为2.33％—35.11％、2.37％—17.78％和1.95％—16.67％。在茂名地区由于冬、春气温不甚低,电光叶蝉仍能继续繁殖越冬,并能不断获菌和传病,所以说该病原是动态越冬的。室内试验表明,带菌电光叶蝉的寿命可长达105—125天,而在茂名的秋收期至翌年春播期一般105天,据此推测有些带菌虫可从秋收后直接存活和传病原到春播稻苗。看麦娘(Alopecurus aequalis)用电光叶蝉人工接种并回接水稻成功。但在病区田间调查从未发现病株。以下植物人工接种不成功:野生稻(Oryzea rufipogon)、小麦(Triticum aestivum)、玉米(Zea mays)、李氏禾(Leersia hexandra)、稗草(Echinochloa crus-gallis)。     

大豆花叶病的流行因素及综合防治

1985年设置流行观察圃,以4个品种、4种播期、两种种子传毒率的种子,系统观察各因素对病害流行的作用。另设综合防治田,品种与观察圃相同;采取隔离种植、种传率低、适期播种及早期拔除病苗等措施。1986年用相同的4个品种,设5个隔离试区,各播种不同种传率(0—33％)的种子,测定播种种子传毒率对流行的影响。结果证明:传毒种子是当地最主要的侵染来源,田间杂草不传病,蚜虫传播距离多在100米以内,花期以后被侵染的植株,其种传率显著降低。播种种子传毒率与田间流行程度及收获种子传毒率相关显著。所用防病措施效果明显,可控制田间病情指数为4％、种传率为0％、种子斑驳率低于4％。     

母株病情严重度同种子传病关系研究

比较８个采自病株的种子的传病情况，结果是母株病指高于３５．６５的４个品种查到病株，而母株病指低于２．８９的４个品种未查到病株。这说明，种子是否传病以及传病程度与产种母株的病情密切相关，产种母株发病重，种子带菌率高，发病就重；产种母株发病轻，种子带菌率低，发病就轻；当产种母株发病轻到一定程度时，种子也可能不表现明显地传病作用。     

黄瓜枯萎病种子带菌的初步研究

黄瓜枯萎病是一种毁灭性病害,近年来发生蔓延较快,种了带菌是传病的主要途径之一。我们于1976—1979年对种子带菌进行了初步研究,现报道如下: 一、病株种子带菌试验 1.病株种子分离:1977年对病株混收种子,进行6期抽样检验,方法是在无菌室内,把受检种子逐粒摆于加入0.01％制霉素和25PPM氯霉素眼药水的马     

水稻叶尖枯病初侵染和再侵染研究

 本研究首次证明水稻叶尖枯病(Phyllosticta oryzicola Hara)的初侵染来源与病残体、病稻种和带菌野生杂草有关。在老病区,病残体特别是落在田中的病叶是主要的初侵染来源。病区稻种带菌率一般为0.5~2.5%,带菌部位几乎都是颖壳。田间无芒稗、西来稗、双穗雀稗、狗尾草、李氏禾、千金子、牛筋草、虎尾草、白茅、菰、马唐和芦竹等10多种禾本科杂草均可是病菌的野生寄主。试验还表明,田间水稻叶尖枯病能够进行再侵染。     

水稻白叶枯病杂草带菌的检验

用反向间接血凝法、噬菌体技术和喷菌法,对安徽全椒、芜湖、石台、合肥等地区上年水稻白叶枯病重病田内和田边的若干种越冬后的植物作带菌检测,结果表明:茭白(Zizanin caduciflora Hand-Mazz)、看麦娘(Alopecurus aequalis Sobol)、菵草(Beckmannia syzigachne(Seud.)Fern)、鹅观草(Roegneria kamojz Ohwi)、艾蒿(Artemisia rulgaris Linn)、紫云英(Astragalus sinicus Linn)等植物带有白叶枯病菌。带菌量的大小,因带菌植物的种类和样品采集的地点而异。在检测的带菌植物中,带菌量较高的有茭白、紫云英等。另用白叶枯菌对多种杂草进行剪叶接菌,经13～20天后,茭白、看麦娘、游草等禾本科杂草的叶片上表现明显症状。杂草病叶的浸泡液与兔抗白叶枯菌的致敏血球产生特异性凝集反应。用噬菌体法也检测到大量活菌;接种稻叶又引起水稻发病。说明在被接种杂草上感染的是白叶枯细菌。     

4种喷雾助剂对解淀粉芽胞杆菌Lx-11的增效作用及安全性评价

为提高解淀粉芽胞杆菌Lx-11悬浮剂对水稻白叶枯病的防治效果，通过研究添加4种喷雾助剂 (有机硅、TM-10、卵磷脂和SY-6535) 对解淀粉芽胞杆菌Lx-11含菌量的影响、药液的表面张力和接触角的变化、助剂对水稻生长的安全性影响等，并测定了添加助剂生防菌对白叶枯病的盆栽防治效果以及在水稻叶表定殖动态，最终筛选出适合的喷雾助剂。结果表明:添加卵磷脂的解淀粉芽胞杆菌Lx-11悬浮剂的含菌量显著降低；添加有机硅、TM-10和SY-6535均能有效降低悬浮剂的表面张力及其在水稻叶片上的接触角。安全性评价显示，有机硅、TM-10和SY-6535对水稻幼苗生长无影响。盆栽试验结果表明，添加TM-10和SY-6535后，解淀粉芽胞杆菌Lx-11悬浮剂 (4.0 × 109 cfu/mL) 对水稻白叶枯病的防治效果达到57.70%和56.56%，显著高于未添加助剂的悬浮剂的防治效果；定殖试验结果表明，添加助剂后，解淀粉芽胞杆菌Lx-11在水稻叶表的定殖量也显著高于对照处理。     

Alternative Route of Infection for Bacterial Seedling Blight of Rice Caused by Burkholderia plantarii

Burkholderia plantarii , the pathogen of bacterial seedling blight of rice, was detected in paddy water. Its concentration rose in July and August. The bacterial concentration in the paddy water was always higher along levees than at distances more than 5 m from levees. Confirmed to be released into water when graminaceous weeds were immersed, B. plantarii survived for at least 4 days at 30°C. B. plantarii was splashed at least 30 cm upward by rain splash in the field. Harvested seeds, which had been sprayed with B. plantarii released from graminaceous weeds at the flowering stage, retained the bacteria. Bacterial seedling blight occurred when the seeds were then sown in nursery boxes. These results indicated that graminaceous weeds growing on levees of paddy fields are a source of infection of the disease and that rice seeds are infected through the paddy water. Received 23 May 2002/ Accepted in revised form 1 September 2002     

Antibacterial activity of two chitosan solutions and their effect on rice bacterial leaf blight and leaf streak

BACKGROUND: Bacterial leaf blight and leaf streak are the two most damaging bacterial diseases of rice. However, few bactericidal chemicals are available for controlling both diseases. The antibacterial properties of two kinds of chitosan with different molecular weights and degrees of N‐deacetylation and their effect on rice bacterial leaf blight and leaf streak were evaluated. RESULTS: Results showed that the two kinds of chitosan solution possess a strong antibacterial activity against both rice bacterial pathogens and significantly reduced disease incidence and severity by comparison with the control under greenhouse conditions. However, the interaction between chitosan and rice pathogens was affected by the type and concentration of chitosan, the bacterial species and the contact time between chitosan and bacteria. The direct antibacterial activity of chitosan may be attributed to both membrane lysis and the destruction of biofilm. In addition, both chitosan solutions significantly increased the activities of phenylalanine ammonia lyase, peroxidase and polyphenol oxidase in rice seedlings following inoculation of two rice pathogens by comparison with the control. CONCLUSION: The role of chitosan in protection of rice against bacterial pathogens has been shown to involve direct antibacterial activity and indirect induced resistance. Copyright © 2012 Society of Chemical Industry     

双核丝核菌诱导水稻增强广谱抗病性和防卫酶系活性

 用无致病性的双核丝核菌(Binucleate Rhizoctonia species,简称BNR)菌株2 32-CG预接种处理水稻品种IR2 6苗期植株根茎基部,可以诱导水稻增强对纹枯病(R.solani Kühn)的抗性。与未处理对照相比,BNR处理水稻植株的纹枯病害严重度明显降低。2 4 h以上的BNR处理,可以彻底保护幼苗不受立枯丝核菌侵染的危害。经BNR诱导的水稻也表现对白叶枯病(Xanthomonas oryzae pv.oryzae)和条斑病(X.oryzae pv.oryzicola)的抗性。BNR可以显著地诱导水稻防卫反应中的2类关键酶——苯丙氨酸解氨酶(PAL)和过氧化物酶(POX)活性提高。受BNR诱导的抗病性与PAL和POX活性呈正相关。对BNR在水稻病害生物防治中的作用进行了讨论。     

水稻细菌性基腐病的侵染规律和病理解剖学研究

 水稻细菌性基腐病是近年来发现并日趋严重的水稻病害.经鉴定,病原菌的细菌学性状与菊欧氏杆菌玉米致病变种(Erwinia chrysanthemi PV.Zeal)相似。本文通过接种实验和扫描电镜观察,证明基腐病细菌可从叶片上的水孔、伤口、受伤的叶鞘和根系侵入,引起不同类型的症状,而以根系侵入为主.首次报导该病原菌侵入后主要在根、茎的气腔中作系统侵染.     

广西水稻内生细菌的动态分布及其对水稻纹枯病菌的拮抗作用

从广西稻区74种水稻品种中采集了222个水稻标样,分离出1903株内生细菌。经形态和生理生化测定,确定这些菌株分属于芽孢杆菌属Bacillus、鞘胺醇单孢菌属Sphingomonas、土壤杆菌属Agrobacterium、伯克霍尔德氏菌属Burkholderia、肠杆菌属Enterobacter和成团泛菌属Pantoea。其中,Bacillus和Enterobacter为主要类群,Bacillus为优势类群。水稻内生细菌的类群随不同的水稻品种和栽培地区而变化。水稻内生细菌在植株器官中的分布以根部数量最多,其次是叶鞘和叶。内生细菌的总量在水稻生育期的变化趋势是从苗期到孕穗期上升,从灌浆期到乳熟期下降。分离到的1903株内生细菌中,有412个菌株对水稻纹枯病菌Rhizoctoniasolani有拮抗作用。     

Identification of a bacterium isolated from galls on carrot and weeds

In 2004, bacterial galls were found on the roots of carrots in Shizuoka Prefecture, Japan. Galls were about 0.1–2 cm in diameter, light brown in color and had rough surfaces. In 2005, similar galls were found on the roots of three weeds: henbit (Lamium amplexicaule L.), Persian speedwell (Veronica persica Poir.) and leaf mustard (Brassica juncea L.). A bacterium that forms white, rough colonies was isolated from the carrot and weeds galls. The bacterial isolates had properties identical with Rhizobacter dauci Goto and Kuwata. Phylogenetic analysis based on 16S rDNA sequences showed that the carrot isolate had the highest homology (similarity of 100%) with that of the type strain of R. dauci. Rep-PCR genomic fingerprinting using BOX A1R primer showed that the carrot and weeds isolates were nearly identical. Pathogenicity of the isolates was confirmed by inoculating the roots of carrots and the weeds. After 2–5 weeks, they formed galls on the roots of the original host species and on other plant species tested. The galls were indistinguishable from those formed naturally, and the inoculated bacterium was reisolated. Thus, the causal bacterium of carrot and weeds gall was identified as R. dauci, and the bacterium was found to have a wider host range than previously known. These weed hosts may serve as inoculum sources for carrot bacterial gall disease.     

水稻白叶枯病带菌稻种的消毒处理

应用噬菌体测定水稻白叶枯病带菌稻种内存活细菌数量的技术,初步找出0.5％盐酸浸种72小时和每毫升含500单位氯霉素浸种48小时,是杀死稻种内病原细菌有效的方法。噬菌体技术必为今后稻种处理药剂的筛选提供一个准确而可靠的方法。     

水稻白叶枯病成株抗性品种病理解剖研究

 成株抗性品种(简称成抗品种)苗期感病阶段和感病品种接种后,病菌在叶片内扩展和繁殖速度快,叶片内部组织变态,导管内菌量多、菌体形态正常;成抗品种成株抗病阶段和全生育期抗病品种(简称全抗品种)与此相反,病菌在接种叶片内扩展和繁殖速度慢,叶片内部组织结构正常,导管内菌量较少.并出现了不同形态的物质,将病菌包围,菌体形状不规则,这些物质在健康叶片、成抗苗期接种叶片和感病品种病叶的导管中未观察到,其形成似乎与品种抗性表现有关系.