疏水表面诱导橡胶树炭疽菌侵染结构的发育分化过程

为了解橡胶树2种炭疽病菌的侵染结构发育分化过程,采用平板菌落生长速率法测定了3株胶孢炭疽菌Colletotrichum gloeosporioides和3株尖孢炭疽菌C.acutatum的菌丝生长速率,测量其分生孢子大小,显微观察2种炭疽菌在疏水表面诱导下侵染结构的发育分化过程。结果表明,胶孢炭疽菌菌丝生长速率为0.96~1.36 cm/d,显著高于尖孢炭疽菌的菌丝生长速率0.72~0.89 cm/d,但二者分生孢子大小无显著差异。在疏水表面诱导下,2种炭疽菌分生孢子在接种2~6 h后开始萌发,12 h孢子萌发率为71.70%~88.05%,13~16 h开始分化附着胞,24 h附着胞形成率为48.99%~70.74%,36 h菌丝诱发形成大量附着枝,48 h后分生孢子产生的次生菌丝也可诱发形成附着枝,附着枝呈圆形、姜瓣形、梨形或不规则形。分生孢子极易产生,可在菌丝顶端成簇或菌丝侧面排列产生,也可由分生孢子形成的芽管产生,或在芽管分化附着胞过程分枝形成分生孢子;附着胞多着生于芽管顶端,少数附着胞顶端可继续萌发类似短芽管结构,再次分化形成可黑色化的次级附着胞。表明橡胶树2种炭疽菌不同菌株间分生孢子萌发时间、孢子萌发率、附着胞形成时间和形成率有一定差异,但种间无明显差异;橡胶树炭疽菌分生孢子极易形成,在疏水表面容易分化形成附着胞和附着枝,说明具有极强的适生性。     

西双版纳海巴戟炭疽病和病原菌分生孢子萌发、附着胞形成条件的研究

对西双版纳海巴戟炭疽病进行调查和病原菌鉴定。结果表明,海巴戟炭疽病周年发生,8月的发病率和病情指数最高,分别为40.76%和8.9。根据病原菌形态特征,将其鉴定为瓜类炭疽菌［Colletotrichum orbiculare (Berk. &; Mont)］。有关温度、pH、光照和碳源对病原菌孢子萌发和附着胞形成影响的研究显示,20～35 ℃,海巴戟炭疽病菌分生孢子萌发率高,20 ℃是形成附着胞的最适温度;最适合海巴戟炭疽病菌分生孢子萌发和形成附着胞的pH为4～8;在日光灯连续光照、12 h光暗交替和自然光照射条件下分生孢子萌发率在90%以上,光照对此病原菌附着胞形成的影响差异不大;1%葡萄糖、麦芽糖、蔗糖、D果糖和α 乳糖溶液中孢子萌发率都不高。     

枸杞褐斑病菌Stigmella lycii生物学特性研究

枸杞小黑梨孢褐斑病自2010年在甘肃省枸杞种植区发现以来已扩展至甘肃省各枸杞种植区,关于其病原枸杞小黑梨孢Stigmella lycii的生物学特性研究国内外尚属空白。本研究通过植物病理学常规方法测定了该菌的生物学特性,结果表明,该菌菌丝生长的温度范围为10~35℃,最适25℃;产孢的温度范围为20~25℃,最适25℃;子囊孢子和分生孢子萌发的温度范围及最适温度分别为5~30℃(最适20℃)和0~35℃(最适25℃)。连续光照有利于菌落生长、产孢和分生孢子萌发,光暗交替有利于子囊孢子萌发;pH 4.0~10.0范围内菌丝均可生长,最适为pH 6.5,产孢的pH范围为6.0~7.0,最适6.5,pH 4.5~9.2条件下孢子均可萌发,最适pH为7.0;子囊孢子和分生孢子分别在相对湿度95%和75%以上可萌发,水中萌发最好;枸杞叶片浸渍液、葡萄糖液等营养条件对孢子萌发有一定促进作用。本研究结果为枸杞小黑梨孢褐斑病后续研究提供一定的理论依据,同时为制定枸杞褐斑病的综合防控措施提供了一定的技术支撑。     

橡胶树白粉病菌分生孢子在不同介质的萌发过程及其内容物的变化

 本研究采用不同的染色方法和显微技术观察橡胶树白粉病菌(Oidium heveae)分生孢子的超微结构,分生孢子在不同介质表面及不同介质溶液中的萌发情况,以及孢子萌发过程中孢内主要物质的变化,以明确O. heveae分生孢子在不同介质萌发的形态变化及萌发所需能量来源。结果表明：O. heveae 分生孢子表面具有较浅的花纹结构,呈椭圆形或者卵圆形,大小为26.1~45.1μm×13.5~21.9μm。O. heveae 分生孢子在亲水和疏水介质上均能萌发产生芽管和附着胞,在葡萄糖水中的萌发率略高于清水中,但萌发率无显著性差异 (P>0.05),芽管和附着胞形成与形态无明显差别。分生孢子萌发过程中,几个液泡会融合形成一个,最终消散而呈不明显可见的泡囊结构。孢子内的糖原、脂质及分裂后的核仁等可通过芽管向附着胞输送,表明O. heveae 分生孢子萌发所需能量物质主要来源于自身能量贮备。     

荔枝炭疽病菌生物学特性的研究

 本文主要研究了温度、湿度、pH值、光照、营养对荔枝炭疽病菌(Colletotrichum gloeosporioides Penz.)生长、产孢和孢子萌发的影响。该菌菌丝生长的温度范围为8~38℃,最适28℃;产生分生孢子的温度范围为12~36℃,最适28~32℃;分生孢子萌发的温度范围为8~38℃,最适28~32℃。在pH 3~10的范围内该菌均能生长和产孢,菌丝生长最适pH 5~6;产生分生孢子最适pH3~4,分生孢子萌发最适pH 6~7。分生孢子在饱和湿度或水滴中萌发快,相对湿度低于85%时不能萌发。光照处理对该菌生长发育无显著性影响。葡萄糖、蔗糖、麦芽糖、果糖对分生孢子萌发有促进作用。分生孢子的致死温度为50℃ 10 min,菌丝体的致死温度为60℃ 30 min。     

喜旱莲子草生防真菌SF-193分生孢子萌发条件及其侵入过程

本研究测定了喜旱莲子草生防菌株SF-193分生孢子的最适萌发条件并观察了其叶面侵入过程。结果显示,在20-30℃、pH5-6、空气相对湿度100%时分生孢子能达到最大萌发率;光照对其萌发无显著影响;pH6、RH100%、28℃黑暗条件下培养4h,分生孢子萌发率接近100%。扫描电镜观察结果显示,SF-193分生孢子在接种4h后萌发形成芽管,6h后在叶片表皮细胞表面形成附着胞侵入叶片组织,24h后次生菌丝转由气孔侵入。     

辣椒胶孢炭疽菌生物学特性初步研究

从广西南宁市采集辣椒炭疽病果实病害标本,进行病原菌分离培养、致病性测定及形态学鉴定,选择引起辣椒炭疽病的病原菌之--胶孢炭疽菌(Colletotrichum gloeosporioides)进行生物学特性研究,结果表明:在测试的不同温度、pH、湿度、光照和营养中,该菌的菌丝体生长和产孢的最适温度分别为25℃和30℃,菌丝体生长和产孢的最适pH值为7,光照对菌丝生长的影响不大,在光暗交替下可促进产孢;分生孢子萌发的最适温度为30℃,最适pH值为7,分生孢子在相对湿度为100%和100%+水滴中能萌发,在100%+水滴中萌发率最高,为99.5%,光照对孢子萌发影响不大;辣椒煎水和辣椒煎水+蔗糖可促进附着胞形成,附着胞在辣椒煎汁中形成率最高,达到90%.     

马唐生防真菌弯孢霉(Curvularia sp.)菌株QZ-200的生物学特性研究

 本文主要研究影响马唐生防菌弯孢霉(curvularia sp.)菌株QZ-200营养生长、孢子萌发及孢子形成的因子。该菌在SCS(黄豆粉-玉米粉-蔗糖)培养基上生长最好;生长温度为10~40℃,最适为28℃;pH为2~11,最适pH为6;在以葡萄糖为碳源、以磷酸氢二铵为N源的Czapek培养基上生长良好。分生孢子萌发的温度为10~45℃,最适为28~30℃,失活温度为52℃10min;pH为2~11,适宜为5~8;以自由水或饱和湿度条件下萌发率最高;1%蛋白胨、1%牛肉浸膏、0.1%的TW-80、1%马唐煎汁和0.2%的菜籽油溶液明显提高萌发速度。该菌孢子形成的温度为15~35℃,最适为28℃;连续光照比光暗12h交替处理更有利于产孢,黑光灯为最佳光源。     

条斑型玉米圆斑病病原鉴定及其生物学特性研究

 本研究通过致病性测定、形态学和分子生物学鉴定方法,首次明确陕西省发生的玉米条斑型叶斑病是玉米圆斑病的一种症状类型,由玉米生离蠕孢(Bipolaris zeicola)3号生理小种引起。供试品种豫玉22、农大108、农大3138、东单7号、沈单10号、沈单16号、户单4号、新陕资1号、高农1号和陕单9号都对3号生理小种表现感病,品种间抗病性差异不显著。此菌在PDA、PSA、OMA、CMA、WA和Czapek上均可生长,最适生长培养基为PDA。菌落生长温度为5~35℃,最适菌落生长温度为25℃。分生孢子在5~40℃均可萌发,低于5℃高于40℃萌发率极低,萌发的最适温度为28℃。孢子在pH 3~11均可萌发,萌发最适pH为5。在自来水中分生孢子可以萌发,蔗糖和葡萄糖溶液可以明显促进孢子萌发。     

小麦白粉菌无性阶段生物学特性研究初报

 小麦白粉菌分生孢子萌发的温度范围为-2~34℃,最适为10~17℃。分生孢子离体后在2℃ 5天,7~17℃ 3天,20℃ 2天都还有侵染力。分生孢子在0~100%的湿度下都可以萌发,湿度愈大萌发率愈高,尤以在水面萌发率最高。分生孢子侵入寄主的湿度必须在65%以上,湿度愈大发病愈重。分生孢子在pH2.2~12.4的范围内都可以萌发,以pH4.2~7.7最适。紫外光对分生孢子有强裂的杀伤作用。在直射阳光下分生孢子的寿命比散光和黑暗条件下短。分生孢子荫发必须要有充足的氧气。光照能促使分生孢子的形成。在自然条件下,分生孢子形成有昼夜变化的规律,白天形成的孢子数比夜间形成的孢子数约大3倍。分生孢子传播的有效距离力15公里以上,传播的有效高度大于979公尺。     

Effect of humidity and temperature on conidial germination and appressorium development of two Philippine isolates of the mango anthracnose pathogen Colletotrichum gloeosporioides

A comparison of rates of germination and appressorium formation by an isolate of Colletotrichum gloeosporioides on mango leaves, fruit surfaces and cellophane membranes showed that behaviour was broadly similar on all three substrates. Frequency of appressorium formation was slightly higher on cellophane membranes, and both hyaline and melanized appressoria were formed. Only melanized appressoria were formed on mango surfaces. In vitro experiments on membranes showed comparative differences in physiological behaviour with temperature for two Philippine isolates of C. gloeosporioides . The most stimulatory temperature for production of appressoria differed in isolates I-2 and I-4 (25 and 20°C, respectively). At 30°C more appressoria became melanized than at lower temperatures, but the frequency of formation of penetration pegs was highest at 25°C. Conidia of C. gloeosporioides germinated on cellophane membranes at relative humidities as low as 95%, but the percentage of conidia germinating and forming appressoria increased as the RH approached 100%. Approximately 18% of conidia of C. gloeosporioides I-2 held at 62 and 86% RH for 4 weeks retained viability, and some were capable of forming appressoria when placed at 100% RH. These results have implications for epidemiological models for disease control.     

Effect of temperature,relative humidity,leaf wetness and leaf age on <Emphasis Type="Italic">Spilocaea oleagina</Emphasis> conidium germination on olive leaves

The effects of temperature, relative humidity (RH), leaf wetness and leaf age on conidium germination were investigated for Spilocaea oleagina, the causal organism of olive leaf spot. Detached leaves of five ages (2, 4, 6, 8 and 10 weeks after emergence), six different temperatures (5, 10, 15, 20, 25 and 30°C), eight wetness periods (0, 6, 9, 12, 18, 24, 36 and 48 h), and three RH levels (60, 80 and 100%) were tested. Results showed that percentage germination decreased linearly in proportion to leaf age (P < 0.001), being 58% at 2 weeks and 35% at 10 weeks. A polynomial equation with linear term of leaf age was developed to describe the effect of leaf age on conidium germination. Temperature significantly (P < 0.001) affected frequencies of conidium germination on wet leaves held at 100% RH, with the effective range being 5 to 25°C. The percent germination was 16.1, 23.9, 38.8, 47.8 and 35.5% germination at 5, 10, 15, 20 and 25°C, respectively, after 24 h. Polynomial models adequately described the frequencies of conidium germination at these conditions over the wetness periods. The rate of germ tube elongation followed a similar trend, except that the optimum was 15°C, with final mean lengths of 175, 228, 248, 215 and 135 μm at 5, 10, 15, 20 and 25°C, respectively after 168 h. Polynomial models satisfactorily described the relationships between temperature and germ tube elongation. Formation of appressoria, when found, occurred 6 h after the first signs of germination. The percentage of germlings with appressoria increased with increasing temperature to a maximum of 43% at 15°C, with no appressoria formed at 25°C after 48 h of incubation. Increasing wetness duration caused increasing numbers of conidia to germinate at all temperatures tested (5–25°C). The minimum leaf wetness periods required for germination at 5, 10, 15, 20 and 25°C were 24, 12, 9, 9 and 12 h, respectively. At 20°C, a shorter wetness period (6 h) was sufficient if germinating conidia were then placed in 100% RH, but not at 80 or 60%. However, no conidia germinated without free water even after 48 h of incubation at 20°C and 100% RH. The models developed in this study should be validated under field conditions. They could be developed into a forecasting component of an integrated system for the control of olive leaf spot.     

Influence of Nutrient and Environmental Factors on Conidial Germination of Potebniamyces pyri

ABSTRACT Potebniamyces pyri is the causal agent of Phacidiopycnis rot, a postharvest disease of pears. Infection of fruit occurs in the orchard, and symptoms develop during storage. Conidial germination of P. pyri in response to nutrient, temperature, wetness duration, relative humidity (RH), and pH was determined in vitro. Conidia germinated by either budding or developing germ tubes in various concentrations of pear juice solutions. The mode of conidial germination was nutrient-dependent. Low nutrient levels favored budding, whereas high nutrient levels favored germ tube development. Conidia germinated at 0 to 30 degrees C but not at 35 degrees C, with optimum temperature between 20 and 25 degrees C. Wetness durations of 4 to 5 h and 6 to 8 h at optimum temperature were required for budding and developing germ tubes, respectively, and 20 to 24 h of wetness was required to reach germination peaks. Regardless of temperature, conidia germinated primarily by budding in 10% pear juice. Secondary conidia, produced by budding of conidia, initially increased their dimensions and later germinated at 0 to 25 degrees C in the same manner as mother conidia. No germination of secondary conidia occurred at 30 degrees C. Germ tubes from conidia elongated at 0 to 25 degrees C but not at 30 degrees C. No germination occurred at 相似文献   

Conidial germination, infection structure formation, and early colony development of powdery mildew on poinsettia

ABSTRACT Powdery mildew disease on poinsettias (Euphorbia pulcherrima) growing in commercial greenhouses was first observed in the United States in 1990 and has become an economically significant problem for poinsettia growers in the Midwest and northern United States since 1992. The temporal development of infection structures produced by conidial germ tubes of the pathogen (Oidium sp.) and the effect of high temperature on their development were investigated using poinsettia leaf disks placed in humidity chambers. Observations were made using light microscopy and scanning electron microscopy. At 20 degrees C (85% relative humidity), conidia germinated and formed an appressorium within 6 h of inoculation. Germination over time followed a monomolecular curve (r(2) = 0.77, P 相似文献   

Germination of Alternaria linicola conidia on linseed: effects of temperature, incubation time, leaf wetness and light regime

Conidia of Alternaria linicola germinated on both water agar and linseed leaves (detached or attached) over a wide range of temperatures (5–25°C) by producing one to several germ tubes. At temperatures between 10°C and 25°C and under continuous wetness in darkness, germination started within 2 h after inoculation and reached a maximum (100%) by 8 to 24 h, depending on temperature. At 5°C, the onset of germination was later and the rate of germ tube elongation was slower than that at 10–25°C. During germination, conidia of A. linicola were sensitive to dry interruptions of wet periods and to light. Short (2 h) or long (12 h) dry interruptions occurring at any time between 2 and 6 h after inoculation stopped conidial germination and germ tube elongation. With continuous wetness, light periods 2 to 12 h long immediately after inoculation inhibited conidial germination, which was resumed only when a dark period followed subsequently. However, germination and germ tube elongation of A. linicola conidia stopped and the viability of the conidia was lost during exposure to dry light periods immediately after inoculation with spore suspensions. Penetration of leaves by A. linicola was evident after 12 h and occurred mainly through epidermal cells (direct) with or without the formation of appressoria.     

Infection process of Phoma koolunga on stem and leaf tissue of resistant and susceptible field pea (Pisum sativum)

This study investigates the infection process of Phoma koolunga on field pea (Pisum sativum) stems and leaves using different susceptible and resistant pea genotypes for each tissue, viz. 05P778‐BSR‐701 (resistant) and 06P830‐(F5)‐BSR‐5 (susceptible) for stems and ATC 866 (resistant) and ATC 5347 (susceptible) for leaves. On both resistant and susceptible genotypes, light and scanning electron microscopy showed P. koolunga conidia infect stem and leaf tissues directly via appressoria or stomatal penetration, but with more infections involving formation of appressoria on stems than on leaves. On leaves of the resistant genotype, at 72 h post‐inoculation, P. koolunga penetrated more frequently via stomata (5.2 conidia per 36 893 μm²) than by formation of appressoria (1.8 conidia); yet no such difference was observed on stems of the resistant genotype. In contrast, at the same time point, the number of conidia infecting the susceptible genotype by formation of appressoria on either stems (135 conidia) or leaves (11.3 conidia) was significantly greater than via stomata (8 and 7.3 conidia, stems and leaves, respectively). Mean germ tube length of germinating P. koolunga conidia on both stems (29.8 μm) and leaves (32.9 μm) of the resistant genotype was less than on the susceptible genotype (40.5 and 63.7 μm, stem and leaves, respectively). In addition, there were differences in the number of germ tubes emerging from conidia on resistant and susceptible genotypes. These are the first insights into the nature of leaf and stem resistance mechanisms operating in field pea against P. koolunga.     

向日葵锈菌夏孢子萌发条件的研究

以向日葵锈菌330生理小种为材料,研究了夏孢子萌发的适宜条件和培养载体。向日葵锈菌夏孢子萌发适宜温度范围10~25℃,最适温度15℃。15℃下在琼脂薄膜上1h即可萌发,12h达到萌发高峰,萌发率最高可达97%。孢子在无菌水中萌发最适浓度为20mg/L,萌发率随浓度增大而降低。光照在前5h均抑制夏孢子萌发,但7h后光照对夏孢子总萌发率基本无影响。新鲜夏孢子萌发率较高,在室温放置270d后基本丧失萌发能力。最适条件下,在供试的6种不同萌发载体上,夏孢子萌发率、芽管长度及萌发形态显著不同,琼脂薄膜载玻片、尼龙纱网、玻璃纸较适宜夏孢子萌发,萌发率超过90%;在PVDF膜和亲水滤膜上可观测到芽管内部黄色物质转移和特殊结构的形成。     

无壳葫芦根腐病病原菌的鉴定及生物学特性初步研究

近年来随着内蒙古无壳葫芦种植面积不断扩大,其病害也越来越严重,其中无壳葫芦根腐病是最普遍、最严重的一种病害。通过对无壳葫芦根腐病的病原菌进行分离、鉴定,确定该病原菌为茄镰孢(Fusarium solani)。本试验利用孢子悬滴法测量孢子萌发10 h后菌丝长度来研究病原菌的生物学特性,比较方便、省时、降低试验费用。该病菌在25℃条件下,菌丝生长速度最快,适应的pH范围较广,偏向于酸性;大型分生孢子萌发条件要求比较宽泛,小型分生孢子萌发条件要求较高,在PS培养液中萌发最好,土壤浸液能够促进分生孢子萌发以及菌丝生长;分生孢子的致死温度为60℃。