南瓜白粉病病原菌鉴定及寄主范围测定

通过对南瓜白粉病病原菌的闭囊壳、分生孢子及萌发方式的观察和鉴别寄主感病反应鉴定,结果表明引起甘肃省武威地区南瓜白粉病的病原菌为苍耳单囊白粉菌Podosphaera xanthii。该白粉病菌闭囊壳形成的最适条件为温度20℃、相对湿度70%和光照强度4,400lx。寄主范围测定结果表明,该病菌不侵染丝瓜、小麦、辣椒、番茄、苜蓿、红三叶草、架豆和菜豆,可侵染除丝瓜之外的其余9种瓜类植物和绿豆、红小豆、向日葵,其中对南瓜、绿豆、西葫芦、红小豆、向日葵、甜瓜和黄瓜的致病性最强,发病率均达到100%,病情指数分别为15.56、14.51、13.33、13.33、13.07、12.22和12.22。侵染过程观察发现,感病南瓜人工接种白粉菌12h后,分生孢子芽管从侧面萌发,于24h芽管伸长,于36h形成菌丝,于72h形成稠密的网状菌丝,于96h形成分生孢子梗及串生分生孢子。     

灌溉对干旱沙区紫花苜蓿生物学特性的影响

研究了干旱沙区不同水分处理下紫花苜蓿的 (Medicago sativa L.)生物学特性。结果表明 ,不同水分处理对紫花苜蓿植株高度、根系伸长生长和地上生物量形成的影响是不同的。在生长季内 ,灌水量最少的喷灌处理 W3植株高度最低 ,灌水量较多的漫灌处理 W1和灌水量居中的喷灌处理 W2植株高度相对较高 ,表明较多的灌水有利于植株高度的生长 ;对于根系长度则相反 ,灌水量最少的喷灌处理 W3根系伸长生长较快 ,到结实后期根系长度达到最大值 1 0 7.60 cm,说明适当的干旱可以促进紫花苜蓿根系伸长生长 ;地上生物量则是灌水量居中的喷灌处理 W2最高 ,表明在干旱沙区这种特殊的环境条件下 ,采取 W2这种灌溉方式种植紫花苜蓿 ,既可以获得较高的地上生物量 ,又可以节约利用水分     

紫芝蛛网病病原菌鉴定及其生物学特性

2021年6月,广西南宁一紫芝培养基地出现疑似蛛网病危害。为明确引起紫芝蛛网病的病原菌,采用组织分离法对病样进行分离纯化,利用多位点基因(ITS,RPB2,TEF1)系统发育学分析、形态学特征观察和致病性测定对分离纯化后的菌株进行鉴定,并开展病原菌的生物学特性研究。明确引起广西南宁紫芝蛛网病的病原菌为凸出枝葡霉Cladobotryum protrusum。该菌菌丝生长的最适培养基为PDA,最佳碳、氮源分别为可溶性淀粉和酵母粉,最适生长温度为25℃,pH为6,黑暗有利于菌丝生长。这是首次报道由C. protrusum引起的紫芝蛛网病。     

灵芝蛛网病病原菌及其生物学特性

为明确吉林省蛟河市灵芝Ganoderma lingzhi栽培主产区发生的疑似灵芝蛛网病的病原菌,作者通过罹病灵芝子实体病原物的分离纯化、致病性测定、形态学和分子生物学鉴定以及病原菌的生物学特性研究,证明引起吉林省蛟河市灵芝蛛网病的病原菌为嗜菌枝葡霉Cladobotryum mycophilum。该菌营养体最适生长条件为温度25℃、pH 5、蔗糖作碳源、酵母浸粉作氮源,光照对菌丝体生长有一定的抑制作用,完全黑暗最适宜生长。本文研究结果为进一步研究该病害的发生规律和防治措施提供了理论参考。     

天麻萌发菌株的生物学特性研究

对4个天麻种子萌发菌菌株在不同培养条件下菌丝的生长进行了研究。结果显示,4个天麻萌发菌的最佳生长温度为25℃,适宜生长的pH值范围为5.0~6.0,最佳培养基为木屑-麸皮培养基。综合试验结果筛选出西乡为一株优良天麻萌发菌。     

一株地黄根腐病病原菌的分离鉴定及生物学特性研究

分离鉴定地黄根腐病的病原菌,对其致病性和生物学特性进行研究.利用平板分离法对地黄根腐病的病原菌进行分离纯化;利用测序技术和遗传进化分析对所得菌株进行鉴定;利用回接试验对所得菌株进行致病性检测;利用生长监测,确定所得菌株的各项生理学特性.获得一株菌落橙黄色,边缘整齐,表面光滑、湿润菌体椭圆形,有疑似出芽现象的真菌;该菌与...     

青岛地区茄白粉病的病原菌鉴定

在青岛地区的保护地和露地发现茄白粉病,通过形态学和分子生物学进行鉴定以及致病性测定。结果将青岛地区茄白粉病的病原鉴定为Podosphaera xanthii,本文为该菌在我国茄子上的首次报道。     

斑玉蕈蛛网病的病原菌及其生物学特性

近期在福建省一家斑玉蕈厂发现一种新病害。为明确该致病菌,通过感病子实体组织分离获得一株病原菌,经过形态特征观察和r DNA-ITS序列分析,确定该病原菌为金黄菌寄生Hypomyces aurantius,该病害名为蛛网病。这是金黄菌寄生所致斑玉蕈蛛网病在国内的首次报道。通过对该病原菌生物学特性的研究,发现其菌丝体最佳生长条件为20℃,p H5.5,葡萄糖为碳源,蛋白胨为氮源,光照对菌丝体生长有一定抑制作用。在出菇过程中严格控制低温条件,同时加强通风和环境卫生管理有助于预防该病害发生。     

梓叶槭种子生物学特性研究

对两个不同种源地的梓叶槭(Acer catalpifolium Rehd.)种子进行了形态结构特性和萌发特性研究,结果表明,梓叶槭种子呈压扁状椭圆形,为无胚乳种子.都江堰种源地的种子千粒重为(28.4±0.81) g,显著大于峨眉山种源地(18.5±0.39)g.种子吸水过程分3个明显阶段:0～1 h是急剧吸水的过程,1～12h吸水较缓慢,12～96h吸水量又急增.温度对2个种源地的种子萌发率有显著影响, 25 ℃是其种子萌发的适宜温度,萌发率分别为48.7%±3.06%(都江堰种源)、42%±2.00%(峨眉山种源),在光照和黑暗条件下,种子萌发率没有显著差异,种子均能正常萌发.     

紫花苜蓿种子萌发及幼苗生理特性对PEG6000模拟渗透势的响应

用不同质量浓度PEG6000(0%、5%、10%、15%、20%、25%、30%,渗透势分别为0、-0.06、-0.17、-0.32、-0.53、-0.79、-1.10 MPa)控制渗透势,研究紫花苜蓿种子萌发及幼苗生理特性对不同渗透势的响应.结果表明: 种子5项萌发指标均随渗透势降低呈先升后降趋势,-0.06 MPa时萌发指数和活力指数最高,-0.17 MPa时发芽率、发芽势和发芽指数最高;幼苗过氧化物酶、超氧化物歧化酶、过氧化氢酶活性和叶绿素含量均随渗透势降低呈先升后降趋势,-0.17 MPa时各指标值最高;叶绿素a/b随渗透势降低呈先降后升趋势,-0.06 MPa时最低;游离脯氨酸、丙二醛含量和相对电导率随渗透势降低而持续升高.渗透势为-0.06～-0.17 MPa时,种子萌发和幼苗生理综合评价结果最优,是最适宜种子萌发的渗透势条件,而当渗透势低于-0.79 MPa时,对种子萌发产生抑制.     

蝉拟青霉LB菌株的生物学特性

本文研究碳源、氮源、温度、湿度、pH值和光照等对蝉拟青霉LB菌株生长、产孢和孢子萌发的影响.结果表明,适合该菌株菌落生长和产孢的最佳碳源是可溶性淀粉和蔗糖,最佳氮源为蛋白胨;菌丝生长和孢子萌发的最适温度范围是25℃～27℃,产生分生孢子的最适温度是25℃;分生孢子萌发所需湿度范围是RH 90%～100%,当RH低于90%时很难萌发;在pH值4～10的范围内该菌能生长和产孢,菌丝生长最适pH为6,产生分生孢子和孢子萌发最适pH范围为6-7;光照处理对该菌产孢有一定的影响;分生孢子的致死条件为55℃ 10min.生物学特性显示,蝉拟青霉LB菌株是一株对营养要求不高、对环境适应能力较强的昆虫病原真菌.     

Altered growth of Fusarium oxysporum f. sp. chrysanthemi in an in vitro dual culture system with the vesicular arbuscular mycorrhizal fungus Glomus intraradices growing on Daucus carota transformed roots

Vesicular arbuscular mycorrhizal fungi can reduce plant disease symptoms and populations of pathogens through mechanisms that are not well understood. Glomus intraradices was grown on Daucus carota transformed roots in a two-compartment in vitro system. One compartment contained mycorrhizal roots on a complete growth medium, while the other contained a medium lacking sugar on which only mycelial growth was allowed. The direct interaction between G. intraradices and Fusarium oxysporum f. sp. chrysanthemi was studied in the compartment lacking sugar during a 5-day period. G. intraradices hyphal density and spore number were estimated along with F. o. chrysanthemi conidial germination, mycelial growth and sporulation. Five hours after inoculation, germination of F. o. chrysanthemi conidia doubled in the presence of G. intraradices. Radial growth of F. o. chrysanthemi colonies was always slightly but significantly enhanced in the presence of G. intraradices. No correlation was obtained between G. intraradices hyphae or spore densities and F. o. chrysanthemi hyphal growth. Overall sporulation of the 5-day-old F. o. chrysanthemi colonies was not influenced by the presence of G. intraradices. However, significant negative correlations were found between F. o. chrysanthemi conidia production and G. intraradices hyphae or spore concentrations. G. intraradices increased F. o. chrysanthemi conidial germination and slightly stimulated its hyphal growth in dual culture without any root influences. No antibiosis was observed between the fungi. The significance of the results and their potential implication for rhizosphere biology are discussed.     

Epichloë endophyte affects the ability of powdery mildew (Blumeria graminis) to colonise drunken horse grass (Achnatherum inebrians)

The effect of the systemic seed-borne endophyte Epichloë gansuensis on the colonization by Blumeria graminis, the cause of powdery mildew disease, and the growth of the host grass Achnatherum inebrians, was studied under four soil water conditions. Infection incidence, disease lesion parameters, disease index, biomass production and growth parameters of the grass with and without the fungal endophyte were measured and counted after a period of disease. There was a significantly (P < 0.05) higher disease incidence and disease index for endophyte-free (E−) compared to endophyte-infected (E+) plants under different drought stresses. The presence of the endophyte significantly positively affected all of the host grass growth factors. The results of the present study demonstrate that the presence of the Epichloë endophyte reduced the ability of B. graminis to colonise A. inebrians and also conferred enhanced host plant growth at all soil water conditions tested.     

琼脂糖和聚丙烯酰胺凝胶电泳技术检测小麦基因组DNA RAPD扩增产物的方法学比较

通过20%(wv)的琼脂糖凝胶和5%(wv)的聚丙烯酰胺凝胶电泳对小麦白粉病抗、感特性品种基因组DNA的RAPD检测结果表明:5%聚丙烯酰胺凝胶对线性DNA分子(01～20kb)和长度相差100bp以下的DNA分子的分离较20%的琼脂糖凝胶电泳效果好。因此,我们研究出了一项利用聚丙烯酰胺凝胶电泳检测小麦白粉病抗、感特性的新技术,在工作中建立了一种适合于检测小麦基因组DNA结构差异的电泳方法。该方法主要包括:(1)丙烯酰胺和亚甲基双丙烯酰胺的新配比;(2)分离DNA片段的最佳凝胶浓度;(3)电泳条件;(4)脱色、漂洗、银染、显色过程。实验发现,该技术对于小麦白粉病抗、感特性检测中的小片段和长度相差100bp以下的线性DNAPCR扩增结果的分辨效果较好。应用该技术在抗感品种间已经发现了DNA水平上的差异。     

亚蔬中心绿豆品种(系)抗白粉病评价

采用苗期人工接种鉴定法,在大棚种植条件下对12个亚蔬中心(AVRDC)绿豆品种白粉病抗性进行了鉴定评价。结果显示,VC1560C、V4785和VC2768A三个品种高抗(HR)白粉病,VC6173-14、V1132为中抗(MR)白粉病品种。其它品种对白粉病表现高度感病。在田间种植条件下对亚蔬中心16个抗豆象回交9代品系(BC9)进行了成株期白粉病抗性鉴定。与对照感病品种 VC1973、VC1178A 相比,VC6459-3-6-37和 VC6458-6-3-16对白粉病具有一定抗性,但白粉病感染程度仍很严重,其它14个 BC9品系均对白粉病表现高度感病。     

胚芽鞘保存麦类白粉菌种的研究

在大小麦感病品种的胚芽鞘大约长1—1.5cm 时接种白粉菌的分生孢子,置17—20℃的室温下20小时左右后,放入1—4℃的冰箱中保存。整个保存期间不加光照。30—40天后,胚芽鞘上长出白粉菌丝和分生孢子。经无病小麦苗接种试验,在3—4℃下小麦白粉菌保存110天、1—3℃下保存150天以上,胚芽鞘上的白粉菌分生孢子仍具有与盆栽麦苗上保存的分生孢子相似的侵染力。用胚芽鞘保存白粉菌种不需附加光照,方法简便,易于保持菌种纯度,保存期长。     

First report of Phyllactinia (Ovulariopsis cf. insolita) in México

Powdery mildew Phyllactinia (Ovulariopsis cf. insolita) is reported on Funastrum clausum and F. cynanchoides in Sinaloa, Mexico. The fungus was reported as Oidium insolitum on Lycium chilense in Argentina, later as Phyllactinia chubutiana (anamorph Ovulariopsis insolita). This fungus was studied by light microscopy and molecular techniques. Fungal mycelium was smooth, effuse, with septate hyphae; appressoria distinct, or ramified; conidiophores pseudoidium type; mature conidium cingulum-like, subcylindric with sub-apical and sub-terminal protuberances. Two rDNA ITS nucleotide sequences were 99% homolog with P. chubutiana's sequence.     

Mechanisms and means of detection of biocontrol activity of Pseudozyma yeasts against plant-pathogenic fungi

Fungi belonging to Pseudozyma spp. represent a small group of yeasts that have drawn limited interest in the scientific literature. However, new research with one species of Pseudozyma, Pseudozyma flocculosa, has demonstrated the potential of this yeast as a biocontrol agent of plant-pathogenic fungi. Based on recent work, it appears that P. flocculosa, a natural inhabitant of the phyllosphere, possesses unique means of defending its ecological niche by producing unusual extracellular fatty acids that are detrimental to, among other fungi, powdery mildews, an important group of plant pathogens. Results from these studies have shown that the fatty acids naturally insert themselves into powdery mildew fungi and cause disorganization of cellular membranes and cell disintegration. Further work with insertional mutagenesis yielded mutants of P. flocculosa that represent valuable biological tools to better understand the properties of the yeast. For instance, preliminary work with mutants having lost their antagonistic properties has led to the isolation of a new metabolite with antifungal activity. Discoveries pertaining to the ecology and mode of action of P. flocculosa may lead to the study of unique metabolic or biological processes in other Pseudozyma spp. that could well release the untapped potential of these misunderstood yeasts.     

内蒙古四个民族耳垂基因频率

本文在调查内蒙古汉族、蒙古族、回族、朝鲜族耳垂性状的基础上,计算出上述4个民族的基因频率,并进行了4个民族之间、 4个民族与赫哲族、柯尔克孜族之间耳垂显性基因频率的比较, 研究结果提示:我国北方地区民族群体的耳垂显性基因频率由西向东有逐渐降低的趋势。