马唐生防真菌MA4的分离鉴定及其生物学特性

【目的】筛选防治马唐（Digitariasanguinalis）的生防真菌,挖掘其应用于杂草生物防治的潜力。【方法】采用组织分离法,从自然发病的马唐植株中分离出对马唐具有较强致病力的生防菌株,通过形态学观察、ITS、β-Tubulin、EF-1α基因序列同源性比对及其系统进化分析确定其分类地位;利用单因素试验研究其生物学特性及整株生物测定法测定马唐生防真菌对几种常见杂草的侵染效果及对常见作物的安全性。【结果】分离得到的马唐生防真菌MA4被鉴定为藤仓镰刀菌（Fusarium fujikuroi）;最适合MA4生长的培养基为PDA和PSA;最适合MA4生长和产孢的培养条件为：温度28～30℃,p H值6.0～8.0,黑暗培养;MA4对马唐鲜重防效较好,达到91.4%,对看麦娘、狗尾草和钻形紫菀的鲜重抑制率分别为63.8%、80.6%、69.4%;MA4对双子叶作物相对安全。【结论】藤仓镰刀菌MA4菌株对马唐等禾本科杂草防治效果较好,对双子叶作物较安全,具有开发成生物除草剂的巨大潜力。     

稗草生防菌新月弯孢菌株J15（2）的生物学特性

研究了分离自稗草上的一个致病菌新月弯孢Curvularia lunata菌株J15（2）的基本生物学特性。结果表明,该菌菌丝生长、产孢的最适温度为28～32℃,pH为6～8。菌丝生长对光照无要求,黑暗利于增加产孢量,培养至15d可达产孢高峰。碳、氮、磷和硫等元素是该菌菌丝体生长、产孢的必需元素,钾、镁和铁对菌丝体的生长、产孢有极大的促进作用。分生孢子萌发的适宜温度范围为20～35℃,最适温度28℃;适宜培养基初始pH值在4～10之间。在58℃下,分生孢子10min失活。     

玉米弯孢霉叶斑病菌生物学特性的研究

 利用小麦黄花叶病毒(Wheat yellow mosaic virus,WYMV)和小麦梭条花叶病毒(wheat spindle streak mosaic virus,WSSMV)的特异性序列为引物,逆转录-PCR方法并配合免疫电镜观察,对采自我国四川陕西、河南、安徽、江苏5省9个县、市的27份感病田小麦样品进行检测。除2份样品未检测到病毒外,其余25份样品均为小麦黄花叶病毒所侵染,没有发现小麦梭条花叶病毒,由此表明在中国长江中、下游、淮河及渭河流域严重危害小麦的真菌传线状病毒应主要为小麦黄花叶病毒。     

胡杨内生真菌曲霉(Aspergillus sp.)链格孢(Altrnaria sp.)的生理特性

采用接种法,对胡杨内生真菌曲霉(Aspergillus sp.)和链格孢(Alternaria sp.)在不同温度、pH、碳源、氮源、培养基及糖质量浓度下进行了生理实验研究.结果表明温度对两种菌株的生长和孢子产生具有明显的影响;曲霉(Aspergillus sp.)pH 5～6时生长良好,而链格孢(Alternaria sp.)pH为4～5时菌株生长良好,两种菌株均以蔗糖为主要碳源;菌丝干质量与培养基质量浓度呈正向关系.     

胡杨内生真菌曲霉(Aspergillus sp.)链格孢(Alternaria sp.)的生理特性

采用接种法 ,对胡杨内生真菌曲霉 ( Aspergillus sp.)和链格孢 ( Alternaria sp.)在不同温度、p H、碳源、氮源、培养基及糖质量浓度下进行了生理实验研究。结果表明 :温度对两种菌株的生长和孢子产生具有明显的影响 ;曲霉 ( Aspergillus sp.) p H5～ 6时生长良好 ,而链格孢 ( Alternaria sp.) p H为 4～ 5时菌株生长良好 ,两种菌株均以蔗糖为主要碳源 ;菌丝干质量与培养基质量浓度呈正向关系。     

生防棘孢木霉T31菌株的分离筛选及其生物学特性

为评价具有生防潜力的棘孢木霉,采用平板对峙法、对扣培养法、圆盘滤膜法从长白山土样中分离筛选出木霉菌株T31,结合形态学及分子生物学分析对其进行种类鉴定,并采用菌丝生长法研究了该菌株的生物学特性。所分离的菌株T31被鉴定为棘孢木霉Trichoderma asperellum,该菌株对8种靶标菌的抑菌率在44.49%~77.91%之间,其中,对玉米大斑病菌Exserohilum turcicum、核盘菌Sclerotinia sclerotiorum、腐霉菌Pythiumuhtimum sp.及镰刀菌Fusarium sp.均有较强生长竞争优势,对玉米灰斑病菌Magnaporthe oryzae具明显重寄生作用。菌株T31的最适培养基为PDA培养基,最适生长温度为30 ℃、最适产孢温度为25 ℃,最适pH值为6。持续光照可以促进木霉菌孢子产生,Zn²⁺、Mn²⁺、Ca²⁺和Mg²⁺利于菌丝生长,但是高浓度的Fe²⁺和Cu²⁺抑制菌丝生长,Mn²⁺和Mg²⁺可促进产孢。此外,与普通木霉菌相比,该菌株具有耐寒性及耐盐性。     

马唐生防菌画眉草弯孢霉毒素α,-βdehydro-curvularin对马唐叶绿体功能的影响

 马唐(Digitaria sanguinalis (L.) Scop.)生防菌画眉草弯孢霉(Curvularia eragrostidis)菌株QZ2000产生一种具有除草剂活性毒素α,β-dehydrocurvularin。通过研究该毒素对马唐类囊体膜光合活性的影响,发现毒素对马唐类囊体膜希尔反应活性、非环式光合磷酸化活性、Mg²⁺-ATP酶活性和Ca²⁺-ATP酶活性均有较强的抑制作用,并且Mg²⁺-ATP酶较Ca²⁺-ATP酶对毒素更为敏感,但毒素不抑制环式光合磷酸化活性。毒素对马唐叶片叶绿素含量影响较小。从试验结果还可看出,非环式光合磷酸化与希尔反应活性及ATP酶活性呈明显的正相关。上述结果表明,该毒素影响马唐叶绿体的功能。另外,根据我们的试验结果及文献报道,该毒素还具有抗菌活性和杀线虫活性,推测叶绿体可能不是该毒素的惟一作用位点。     

水葫芦生防菌尾孢霉属菌株FJ24的生物学特性

测定了从福建省得到的水葫芦致病菌——尾孢霉属菌株FJ24,在不同光照、温度、pH值、碳源、氮源和培养基等条件下菌丝的生长情况。结果表明,全黑暗条件有利于菌丝生长,温度为30℃、pH值为7.6时菌丝生长最快。最适培养基为MDYEA,最适碳源是可溶性淀粉,最适氮源为乙酸铵。     

四脊裸孢壳Dh菌株的生物学特性及对沙枣尺蠖的防治效果

从沙枣尺蠖上分离到一真菌菌株Dh，经鉴定为四脊裸孢壳。该菌喜温，生长温度范围为15～45℃，最适温度为30℃；病菌在pH4～8之间生长良好；孢子的萌发温度范围为8～45℃，以30℃为最适；在黑暗、日光灯、黑暗与散射光交替、自然光条件下，该菌的生长与产孢情况无明显的差异；该菌能利用葡萄糖、蔗糖等多种碳源，在可溶性淀粉、甘露醇和麦芽糖上生长量最大；可利用多种氮源，尤其对尿素、氯化铵的利用最好。Dh经纯化培养后，室内对沙枣尺蠖致死率达86．42％，田间致死率达82．13％。     

橡胶树棒孢霉落叶病病原菌的生物学特性

通过对橡胶多主棒孢进行生物学特性研究,结果表明:菌丝生长的适宜温度范围为25～30℃,最适温度为30℃;最适pH范围为4～8;菌丝在以麦芽糖为碳源和以KNO3为氮源的培养基上生长最好。分生孢子萌发的适宜温度范围为20～35℃,最适温度为25℃;水滴是孢子萌发的必要条件;在不同的pH条件下分生孢子萌发无明显差异;分生孢子在果糖中萌发率最低。     

Phaeosphaeria sp.HD-06菌株对马唐的致病性分析及初步鉴定

为了得到能够有效抑制马唐Digitaria sanguinalis生长的生防微生物,在农田采集马唐种子,进行萌发试验,观察种子的萌发状况,从发病的种子和马唐幼苗基部分离致病菌,通过形态学观察以及ITS序列分析对致病菌进行鉴定。结果从罹病的马唐幼苗基部分离得到一株致病菌HD-06,该菌株的发酵液用水稀释至60%浓度时,对马唐种子的萌发抑制率和幼苗发病率均达到100%,这说明菌株HD-06对马唐有较好的生物防治作用。根据其形态学特点及ITS序列分析结果,鉴定菌株HD-06为暗球腔菌属Phaeosphaeria的真菌。这些结果为深入研究其对马唐的防治作用奠定了基础。     

马唐病原真菌的分离筛选及其致病力测定

从马唐罹病植株上分离到 6种病原真菌 :中隔弯孢、新月弯孢、多节长蠕孢、灰梨孢、链格孢和粉红镰孢。其中新月弯孢和多节长蠕孢对玉米有致病作用 ,灰梨孢对水稻有轻微的致病作用 ;另3种病原真菌中 ,链格孢和粉红镰孢对马唐致病性弱 ,而中隔弯孢菌株对 4叶期以下的马唐有极强的致病作用 ,室内控制效果可达 1 0 0 % ,田间控制可达 75%以上。对中隔弯孢菌株QZ 2 0 0寄主范围测定表明 :该菌对水稻、玉米、大豆、棉花、小麦、向日葵、花生等作物及黑麦草、高羊茅和狗牙根等草坪草十分安全 ,具有开发为作物田和草坪真菌除草剂的潜力     

马唐种子萌发及幼苗建成对不同环境因子的响应

马唐是我国常见的旱田杂草之一,然而近年来在部分地区直播稻田危害十分严重.本研究测定了马唐种子萌发和幼苗建成过程中对不同环境因子的响应特征,以期为直播稻田马唐综合防控提供科学依据.结果表明:马唐在 L//D=12 h//12 h,光照/黑暗阶段温度分别为40℃/30℃、35℃/25℃、30℃/20℃、25℃/15℃、20...     

Demography of Digitaria sanguinalis: Effect of the emergence time on survival,reproduction, and biomass

Knowledge of weed population dynamics is crucial for designing effective weed management practises. A field experiment was carried out at Torre Marimon (near Barcelona, north‐eastern Spain) in 2006 and 2007 in order to study the effects of the seedling emergence time on Digitaria sanguinalis fitness. Three and four cohorts were monitored in 2006 and 2007, respectively. In 2007, the seedling density was fourfold greater than in 2006. At the end of the growing season, no statistically significant differences in survival were detected among the cohorts in 2006 (the mean survival rate was 88%); in contrast, in 2007, individual survival varied depending on the cohort, ranging from 25–88%. The reproductive traits and seed production were significantly influenced by the emergence time. In the cohorts that emerged very close in time, the individuals of the first cohort on average had more than threefold the amount of seed production than those of the last cohort. However, not all the surviving individuals were able to reproduce because they were infected by the smut, Ustilago syntherismae.     

Mesotrione control and pigment concentration of large crabgrass (Digitaria sanguinalis) under varying environmental conditions

BACKGROUND: Mesotrione is a carotenoid biosynthesis‐inhibiting herbicide currently labeled for crabgrass (Digitaria spp.) control. Mesotrione control of large crabgrass has been reported to vary with temperature and relative humidity; however, the effect of irradiance on mesotrione efficacy has not previously been reported. Likewise, little is known about pigment concentrations of Digitaria spp. The present research investigated the effects of mesotrione on large crabgrass, Digitaria sanguinalis (L.) Scop., control and pigment concentrations under varying irradiance at three temperatures. RESULTS: Mesotrione (0.28 kg ha^?1) control of large crabgrass did not differ between temperature levels (18, 26 and 32 °C). Control was similar at tested irradiance levels (600, 1100 and 1600 µmol m^?2 s^?1). Mesotrione reduced large crabgrass chlorophyll a, chlorophyll b and total carotenoid concentrations, as well as chlorophyll a to b ratios. Treated plant bleaching was highest 7 days after treatment (DAT) but decreased by 21 DAT. Treated plants were less than 10% necrotic 3 and 7 DAT but nearly 35% necrotic 21 DAT. Treated large crabgrass bleaching was highest and photochemical efficiency was lowest 7 DAT. These results indicate that some plant recovery occurs prior to 21 DAT. CONCLUSION: Although mesotrione efficacy has previously been reported to vary according to environmental factors, mesotrione control of large crabgrass did not vary with measured temperature and irradiance levels in this study. On account of crabgrass convalescence, secondary applications of mesotrione may control large crabgrass more effectively when applied prior to 21 DAT. Copyright © 2009 Society of Chemical Industry     

小麦条锈菌冬孢子生物学特性研究进展

由小麦条锈菌引起的小麦条锈病是我国广大麦区的严重病害,研究其冬孢子产生原因与作用对于解析该病菌的生活史及遗传变异机制至关重要.通过对国内外相关研究成果的整理,综述了小麦条锈菌冬孢子的形态特征、生物学特性、寄主范围及其作用与功能等方面的研究进展.     

Chlamydospores of Fusarium Oxysporum Schlecht f.sp. orthoceras (Appel & Wollenw.) Bilai as Inoculum for Wheat-flour—Kaolin Granules to be Used for the Biological Control of Orobanche cumana Wallr.

The formation of chlamydospores of Fusarium oxysporum Schlecht. f.sp. orthoceras (Appel & Wollenw.) Bilai, a potential mycoherbicide for the parasitic weed Orobanche cumana Wallr., was optimised regarding the composition of the liquid growth medium. After 16 days of incubation, highest chlamydospore counts (approximately 2 × 10⁷ml^–1) were determined in an aqueous solution amended with 1.5% (w/v) finely ground sorghum stover and 30% (v/v) wheat-based stillage, a liquid by-product of ethanol production. The produced fungal biomass retained viability after being air-dried and stored. Granules made from wheat-flour and kaolin (Pesta) containing microconidia or air-dried chlamydospore-rich biomass were prepared and showed high efficacy in controlling O. cumana in the greenhouse. No differences in efficacy were observed between the different types of inoculum used.     

石楠叶锈病菌 Aecidium wenshanense 锈孢子萌发的生物学特性

为了解由文山春孢锈菌Aecidium wenshanense引起的石楠叶锈病的发生发展及流行规律,为病害的防治提供依据,本文以椭圆叶石楠Photinia beckii发病植株叶上的新鲜锈孢子为试验材料,采用水琼脂平板孢子萌发法对温度、湿度、光照、酸碱度及寄主汁液等条件对该锈孢子萌发的影响进行了研究。结果表明,该锈菌锈孢子在温度5～30℃和pH3～10的范围内都能萌发,最适温度为20～25℃;最适pH为6～8;相对湿度大于或等于90%时孢子才能萌发,最适湿度为100%+水;连续光照抑制孢子萌发,而连续黑暗条件下孢子萌发率最高。寄主(椭圆叶石楠)老叶的新鲜汁液对锈孢子的萌发有一定抑制作用。