烟草赤星病菌分生孢子产生条件的研究

试验研究了烟草赤星病菌分生孢子的产生条件。结果表明:葡萄糖是最好的碳源,有机氮远比无机氮好,Czapek培养基对孢子形成最适宜。病斑产孢潜能高峰在日龄27 d,产孢最适温度为24℃,相对湿度在88%以下,病斑不能产孢,在90%~100%范围内,随相对湿度增加产孢量急剧增加,在连续保湿5 h以下,病斑不能产孢,在7~24 h范围内,时间越长,产孢量越大。     

低能氮离子束诱变选育捕食线虫性真菌——少孢节丛孢菌

为获取理想的生物防治捕食线虫性真菌菌株,达到利用自然天敌有效控制家畜寄生性线虫病的目的,作者利用低能氮离子注入诱变捕食线虫性真菌——少孢节丛胞菌(Arthrobotrys oligospora)的分生孢子,测定分生孢子萌发后菌丝的生长速度、产孢能力及菌株对线虫幼虫的捕食率,筛选正突变株。结果表明,低能氮离子束具有诱变少孢节丛孢菌的潜能,诱变后的1株少孢节丛孢菌的生长速度、产孢量和对线虫幼虫的捕食率呈现出了正突变效果。     

Aggressiveness of Phytophthora infestans on detached potato leaflets in four Nordic countries

Potato fields in Denmark, Finland, Norway and Sweden were sampled for single-lesion isolates of Phytophthora infestans . The aggressiveness of the isolates was determined on detached leaflets of potato cvs Bintje (susceptible) and Matilda (moderately resistant). The aggressiveness tests were carried out in the respective home countries of the isolates, with the exception of the Danish isolates. Fifteen Danish isolates were studied in each of the other three countries, including five isolates tested in all three laboratories. Results obtained from the Danish isolates revealed substantial differences between the test laboratories for infection efficiency, lesion growth rate and sporulation capacity on detached leaflets. When the laboratory effect was taken into account, the differences in aggressiveness between the countries were generally small or inconsistent between the test cultivars and epidemiologically insignificant. By contrast, variation among isolates within countries was substantial. The magnitude of the variation depended on country and cultivar. Maximal variation for the means of the isolates was between 89 and 185 h for latent period, between 100 and 1297 sporangia mm⁻² for sporulation capacity and between nearly zero and 6 mm day⁻¹ for lesion growth rate. Typically less than 1% of sporangia were able to cause infections, except in Norway. These extraordinarily low values may be an artefact of the testing method. High variation in results between the test laboratories emphasizes the need for caution when comparing results obtained by different research groups.     

避雨栽培对葡萄霜霉病发生的影响与葡萄冠层微气象因子的关系

系统比较了云南省石林县(‘红地球’)和弥勒县(‘水晶葡萄’)葡萄园采用避雨栽培和露天栽培对葡萄霜霉病Plasmoparaviticola(Berk.Curtis)Berl.de Toni.的防治效果,监测了田间葡萄园内避雨栽培和露天栽培处理中葡萄霜霉病的发生流行与植株冠层气象因子的变化情况,并结合适宜葡萄霜霉病病害循环的温度、相对湿度、叶面持露时间及田间葡萄植株冠层微气象因子的变化对避雨栽培有效防治葡萄霜霉病的气象原理进行了分析。结果表明,避雨处理可有效控制葡萄霜霉病的发生和危害,石林县和弥勒县两地葡萄园的防治效果分别达到97.84%和66.29%。弥勒县‘水晶葡萄’对霜霉病的抗性较强,霜霉病发生较轻,但在避雨栽培条件下霜霉病的病情指数也显著低于对照。植株冠层微气象因子变化分析表明,避雨栽培可以减少决定霜霉病菌能否成功侵染的叶面水膜持续时间,创造不适宜霜霉病菌萌发和侵入的条件,还可以显著减低棚内植株冠层适宜孢子囊产生的相对湿度的持续时间,减少霜霉病菌的侵染菌量,从而有效地控制了霜霉病的发生和危害。     

白僵菌在土壤中宿存的数量、毒力及产孢量变化研究

研究白僵菌在土壤中宿存情况,结果表明,球孢白僵菌在土壤中宿存两个月内,成菌落数呈波动状态,下降较慢,1g、5g、10g区分别下降50%,60%和64%。自第3个月起,成菌落数每月下降85%至95%,最终土壤中的成菌落数维持在10^3-10^4CFU/土样水平。不同处理浓度表明,处理浓度过大不利于白僵菌的长期缩存;而白僵菌在缩存过程中,其毒力和产孢能力的稳定性有利于害虫的持续控制。     

食线虫性真菌Duddingtonia flagrans F088的生长和产孢特性

【目的】研究食线虫性真菌Duddingtonia flagrans生长特性和不同营养要素对产孢量的影响,为其规模化发酵工艺的确定提供参考。【方法】以D.flagrans F088分离株为研究对象,研究该菌培养过程中pH值、厚垣孢子产量、菌丝干质量等指标的变化;通过单因素试验及正交试验,研究几种常见碳源、氮源、无机盐、维生素和碳氮比对厚垣孢子产量和菌丝平均生长速率的影响。【结果】供试真菌在培养2 d后进入对数生长期,4 d时达到高峰(OD_(600)值为7.46,菌丝干质量为12.07 g/L),而pH快速下降至4.45;3 d开始产生厚垣孢子,4 d时呈爆发式增长。OD_(600)与菌丝干质量、厚垣孢子产量呈极显著正相关,与pH呈极显著负相关。单因素试验结果表明,产生厚垣孢子的最佳碳源为白糖,氮源为大豆蛋白胨,碳氮比为40∶1,维生素为V_(B_1)、无机盐为MgSO_4;菌丝生长较好的碳源为红糖,氮源为大豆蛋白胨,与对照相比,无机盐和维生素对菌丝生长无显著促进作用。4因素3水平正交试验结果显示,D.flagrans F088产生厚垣孢子和菌丝生长的最佳配方组合为:30 g/L白糖、4 g/L大豆蛋白胨、1 g/L MgSO_4和30 mg/L V_(B_1)。【结论】初步明确了D.flagrans F088培养过程中pH、厚垣孢子产量、菌丝干质量等的变化趋势,确定了该菌菌丝平均生长速率和厚垣孢子产量达到最佳时的营养要素和配方组成。     

Potential for Incorporation of Early and Late Leafspot Resistance in Peanut*

A detached leaf technique was used to evaluate components of resistance to both early and late leafspot caused by Cercospora arachidicola Hori and Cercosporidium personatum (Berk, and Curt.) Deighton, respectively, for F₂ plants of two peanut (Arachis hypogaea L.) crosses (FESR 5-P2-B1 /PI 269685 and PI 35068Q/GP-NC 343), No negative correlations were obtained when comparing components of resistance to early leafspot with components of resistance to late leafspot, indicating that the resistances are inherited independently. A small number of F₂ plants had greater partial resistance to both leafspots than their parents when evaluated by an index including percent necrotic area, latent period and sporulation. Broad sense heritabilities of resistance components were moderate to high (0.4 to 0.8) for the F₂ populations. A visual sporulation rating scale was significantly correlated (0.8 to 0.9) with conidia per lesion and conidia per necrotic area. The data suggest that peanut cultivars resistant to both leafspots can be developed.     

九株绿僵菌液体振荡培养初步研究

本文对九株绿僵菌液体振荡培养的研究表明，不同氮源和菌株对菌丝生长量和液生孢子产孢量影响显著．某些绿僵菌菌株可以微循环产孢形式直接产生液生分生孢子，但微循环产孢现象发生与否可能与菌株有一定的相关性．     

淡紫拟青霉NH-PL-03菌株的培养特性

跟踪检测了淡紫拟青霉NH PL 03菌株液体培养过程中D(620nm)值、pH值、菌丝干重、产孢量以及基质消耗 (碳、氮)等培养参数,对培养因子进行了相关分析和主成分分析,并对该菌株的培养阶段进行了聚类分析.结果表明:菌丝干重、产孢量、D(620nm)值分别与营养生长、生殖生长、生理特性主成分;基质消耗 (C、N)与产物生成呈显著相关;当λ=2. 582时,可将淡紫拟青霉菌株NH PL 03培养过程分为 4个阶段,第 1阶段为适应期,培养时间为 1 -2d,菌的培养参数变化不大;第 2阶段为生长期,培养时间为 3-5d,菌体开始生长,D(620nm)值上升,pH值下降,菌丝和产孢量增加;第 3阶段为对数期,培养时间为 6-7d,D(620nm)值、pH值上升,菌丝和产孢量急剧增加; 8d后进入稳定期 (第 4阶段 ),D(620nm)值、pH值趋于稳定,菌丝干重和产孢量达到峰值并趋于稳定.     

Variations on conserved signaling pathways in biocontrol and development:G protein and MAPK genes of Trichoderma. atroviride and T. virens

Filamentous fungi employ conserved eukaryotic signaling pathway to detect and respond to environmental signals, including the presence of the host. Genetic experiment in which a particular signaling protein is lost, or its activity enhanced, have defined some of the function of heterotrimeric G proteins and MAP kinases in development and virulence. A hallmark of these studies is that orthologs in different species may have different functions. Antagonistic fungal-fungal interactions form …