Effects of temperature,free moisture duration and inoculum concentration on infection of sweet cherry by<Emphasis Type="Italic">Pseudomonas syringae</Emphasis> pv.<Emphasis Type="Italic">syringae</Emphasis>

The effects of temperature, free moisture duration and inoculum concentration on infection caused byPseudomonas syringae pv.syringae (Pss), on sweet cherry (Prunus avium) were investigated. Epiphytic populations ofPss are an important source of inoculum for bacterial canker and it has been demonstrated that a cyclic pattern exists during the year, from undetectable during the warm and dry periods to large populations following cool and wet periods. The effects of temperature and inoculum concentration on the infection caused byPss on immature fruits and 1-yr-old twigs were significant (P<0.001). Fruit and twig infection increased linearly in proportion to the logarithm ofPss when bacterial concentrations were higher than 10³ cfu ml⁻¹ and temperatures were between 5 and 20°C. Regardless of the inoculum concentration and the free moisture duration, fruit and twig infection was either absent or low at 5°C but it increased linearly as temperature increased from 5 to 20°C. Growth ratein vitro was very slow (0.03–0.04 cfu h⁻¹) at 5°C and fast (0.21–0.23 cfu h⁻¹) at 20°C. Therefore, it is possible that multiplication of the epiphytic populations may be significantly reduced in the field with air temperatures below 5°C. A significant (P<0.001) effect of free moisture was obtained only when a low inoculum concentration (10³ cfu ml⁻¹) was used, and a significant linear response between free moisture and disease incidence was obtained only at 10°C. An apparent threshold population ofPss higher than 10³ cfu ml⁻¹ was needed to infect immature fruits and 1-yr-old twigs of sweet cherry. http://www.phytoparasitica.org posting July 10, 2002.     

Enhanced tomato resistance to bacterial canker by application of turtle oil

Pretreatment with oil of sea turtle Caretta caretta protected tomato plants against bacterial canker caused by Clavibacter michiganensis subsp. michiganensis (Cmm). The turtle oil was ineffective in inhibiting Cmm in an agar diffusion test, suggesting a mechanism of induced resistance. Under controlled conditions in the greenhouse, turtle oil lowered the disease index and had reduced the growth of bacteria up to 50.4% by 7 days after inoculation. Applying turtle oil to the foliage of tomato plants increased per-oxidase and lipoxygenase activities. Gas chromatography analyses of turtle oil indicated the presence of polyunsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid. These fatty acids may lead to the higher activity of the enzymes and probably induced plant resistance against the pathogen.     

杨树溃疡病流行与土壤条件的关系

土壤条件对箭杆杨溃疡病的流行与抗病性及发病程度具有明显影响。40～60cm深层土壤中的速效P与病情指数是显著正相关,pH与病情指数呈负相关。树皮中全P含量与该层土壤速效P含量及感病指数均具有显著的正相关性。通径分析指出,该层土壤的速效P及其pH对病情指数产生正效应;而全N、速效K对病情指数产生负效应。它们的效应大小依次为:P>K>N>pH。     

杨树溃疡病测报技术的研究

通过在西北林学院苗圃的北京杨上进行孢子捕捉和病情调查，利用气象因子中的温度（Ｘ１）、湿度（Ｘ２）、降雨量（Ｘ３）、温湿比（Ｘ６）、雨温比（Ｘ７）、雨湿比（Ｘ８）以及树皮相对膨胀度ＲＴ％（Ｘ４）和孢子数（Ｘ５）来分别预测４０ｄ后的病情指数（ｙ）以及第四个１０天内新出现病斑数量（ｙ′）和病情指数增长值（ｙ″）。利用ＳＹＳＴＡＴ软件分别做多元线性回归、逐步回归和非线性回归，得到三个模型，经过实际病情验证，均有较高的准确性     

番茄细菌性溃疡病苗期接种新方法的研究

 在剪叶、浸根和针刺等细菌病害传统接种方法基础上设计了打顶接种新方法;以番茄细菌性溃疡病菌中国菌株和美国菌株借助打顶法接种佳粉10、合作908和华南红宝石3个国内主栽番茄品种2~3片真叶期幼苗,在昼夜最低、最高温度15~18℃、32~35℃和相对湿度为30%~60%的温室条件下,打顶法接种番茄幼苗后溃疡病发病率为87.5%~100.0%,病情指数随接种菌悬液浓度提高而增大,达到23.96~82.29,3个供试品种之间表现稳定一致;剪叶、浸根和针刺接种方法的发病率普遍在40%以下,病情指数在20以下,3个供试品种之间未表现明显差异;进一步研究显示,使用选择性培养基mSCM能够从打顶法接种后的发病植株上获得培养性状与原接种体一致的分离物,专化性免疫凝聚试剂盒检测到特定的测试线,PCR扩增到614bp的特异性条带,证实该分离物为番茄细菌性溃疡病菌,发病植株为接种体侵染所致。该研究结果表明,打顶接种方法比剪叶法、针刺法和浸根法更适合用于番茄溃疡病菌的致病性测定和评价不同番茄品种苗期的抗病性,具有应用价值。     

Genetic characterization of Gremmeniella abietina var. abietina isolates from Spain

The taxonomic placement of Spanish isolates of Gremmeniella abietina var. abietina (Gaa) (race and biotype) was determined, for the first time, using RAPD markers and comparison of RAPD patterns for Spanish isolates and those originating from different regions of Europe and North America. Fifteen Spanish isolates of Gaa were isolated from recently dead shoots of 10 Pinus halepensis trees. Additionally, 17 isolates of Gaa from Canada, Finland, Switzerland and the USA, previously characterized according to race and biotype, were used. Five primers, previously reported to yield readable, reproducible and polymorphic fragments, were used in PCR reactions. The results showed that the Spanish isolates represent the European race and not the Alpine or northern biotypes. Spanish isolates appear to be clearly separated from all other biotypes within the EU race and preliminary data suggest that Spanish isolates have low genetic variability.     

猕猴桃品种中糖分及木质素含量 与抗溃疡病的关系

以安徽省猕猴桃主栽品种金魁、早鲜、魁蜜和金丰为研究对象，于展叶孕蕾期分别取发病的枝条、叶片，以未发病的健株相应组织为对照，采用生理生化的方法，分析枝条、叶片中木质素和可溶性糖的含量变化以及与抗溃疡病的关系。结果表明：抗病品种金魁健株枝条、叶片中可溶性糖及木质素含量显著高于感病品种金丰。自然发病后，抗感病品种枝条、叶片中可溶性糖含量都降低，感病品种降低更多，金魁叶片可溶性糖含量下降4．20％，金丰叶片可溶性糖含量下降55.35％；木质素含量都升高，且抗病品种金魁叶片中的木质素含量比感病品种金丰高得多，其变化率分别为7．17％、3．01％，枝条中的木质素含量变化率分别为110．39％、68．98％，其差异达到显著水平。相关分析表明，枝条中木质素、可溶性糖含量与品种发病率也呈负相关，γ分别为-0．9583和-0．9282；叶片中木质素、可溶性糖含量与品种发病率呈负相关，γ分别为-0．8099和-0、8266。从而说明枝条、叶片中可溶性糖及木质素含量与品种抗性呈正相关。抗感品种淀粉含量无明显规律性变化，与品种抗性关系不大。     

中国桉树真菌病原汇录：2006-2013

本文对2006-2013年期间我国感病桉树或桉树木片上发现的21个真菌物种的分类地位、形态特征、菌落特点、寄主范围、分布地域和危害特点等进行了概述。介绍的对象包括桉树枝干斑点溃疡病原 Teratosphaeria zuluensis（祖鲁畸腔菌）;桉树叶部斑点溃疡病原Teratosphaeria destructans（破畸腔菌）,Mycosphaerella marksii（马克氏球腔菌）,M. crystallina（水晶球腔菌）,M. yunnanensis（云南球腔菌）;桉树顶梢及叶白枯萎病原 Quambalaria pitereka（彼特氏桉座孢）;桉树苗茎腐病原 Calonectria cerciana（桉树丽赤壳）,C. pauciramosa（常丽赤壳）,C. pseudoreteaudii（瑞丽赤壳）;桉树叶焦枯病原 C. crousiana（克儒斯氏丽赤壳）,C. fujianensis（福建丽赤壳）,C. pauciramosa（常丽赤壳）, C. pseudocolhounii（类柯氏丽赤壳）,C. pseudoreteaudii（瑞丽赤壳）;桉树木片腐烂病原Ophiostoma tsotsi（类栎长喙壳菌）;桉树枝干溃疡病原Chrysoporthe deuterocubensis（类古巴黄隐丛赤壳）,Fusicoccum fabicercianum（法比桉树壳梭孢）,Lasiodiplodia theobromae（柯柯豆毛色二孢）,L. pseudotheobromae（类柯柯豆毛色二孢）,Celoporthe guangdongensis（广东暗隐丛赤壳）,C. eucalypti（桉树暗隐丛赤壳）;桉树枝干枯萎病原Ceratocystis acaciivora（相思长喙壳）,C. chinaeucensis（中国桉树长喙壳）。     

杉木溃疡病病原生物学及其防治的研究

杉木溃疡病是由真菌-菌葡萄座腔菌(Botryosphaeria cunningha-miae Huang)所致。从该菌丝的生长和孢子萌发情况看:其温度范围为13—32℃适宜温度在24—28℃。在pH值3—9均能生长,以pH值为5—6生长最好。要求湿度较高,且以水滴下生长最佳。在PDA和黄豆葡萄糖培养基上,菌丝生长旺盛,菌落生长亦快,20多天后逐渐产生较多的黑色子囊腔组织,发现有子囊形成。该菌在葡萄糖、蛋白胨上,菌落生长快但稀薄,在麦芽糖、脲素上,菌落生长慢却厚密,脲素、麦芽糖有利于黑色子囊腔组织的形成。用异稻瘟净防治该病。     

苹果树腐烂病病原种类及其亲缘关系分析

【目的】研究苹果树腐烂病菌的种类及其亲缘关系,为有效防治苹果树腐烂病提供理论依据。【方法】以阿克苏地区不同区域苹果树腐烂病病样为材料,采用常规组织分离法和枝条烫伤接种法分离和鉴定菌株,记录形态学特征和发病情况;利用分子生物学方法获得β-tubulin与EF1-α序列,在NCBI网站对比分析Blast同源性,采用邻接法构建系统发育树分析同源性。【结果】菌丝生长最适温度 20~30℃,最适pH值为5~6,最适碳氮源分别是葡萄糖和蛋白胨;共分离出11个菌株,将菌株接种到健康苹果枝条上均可发病且能分离出相同的菌株,各菌株分别与Valsa mali和Valsa ceratosperma具有较近的亲缘关系。【结论】阿克苏地区苹果树腐烂病菌为黑腐皮壳属V. mali(无性型C. mali)和V. ceratosperma(无性型C. sacculus),其中V. mali为阿克苏地区的主要致病种,在PDA上存在不同类型的培养性状。