中国小麦雪霉叶枯病菌种的鉴定

系统研究和鉴定了产自中国陕西、青海、宁夏、四川、贵州、西藏、湖北、新疆等8个省区的31个小麦雪霉叶枯病菌菌系和1个产自捷克的菌系。结果表明,各菌系的培养性状和形态特征、尤其是环痕状的产孢细胞和具淀粉质顶环的子囊等均符合 Gerlachia nivalis (Ces.Ex Sate．)W．Gares & E．Mdll．[有性态：Monographella nivalis (Schaffn·)E·Mfill·]的鉴别特征。小麦雪霉叶桔病菌对三唑酮等8种药物比镰刀菌敏感,各菌系人工接种小麦幼苗均引起相同症状,人工接种可侵染22属55种禾本科植物。确认了该菌与欧洲、北美发生的红色雪霉病病菌为同种。因此,将中国小麦雪霉叶枯病菌定名为雪腐格氏霉[Gerlaehia nivalis(Ces．Ex Saee．)W．Gams ＆ E. Miill.]。     

林生地霉培养基形态学观察及生理学实验

目的观察林生地霉在5种不同培养基中的形态;通过一些常规的生理学实验,初步了解林生地霉的生理学特征。方法将林生地霉分别接种在沙堡培养基(SDA)、马铃薯葡萄糖琼脂(PDA)、麦芽汁琼脂(MEA)、玉米粉琼脂(CMA)和察氏琼脂(CZA)平皿培养基上,置37℃和27℃温箱培养2周,每天观察菌落生长情况。通过芽管试验、厚壁孢子试验、硝酸盐同化试验、放线菌酮耐受试验、尿素酶试验、糖发酵试验及API20C酵母系统等初步了解林生地霉的生理学特性。结果菌落在PDA、SDA和MEA培养基上生长较快、较好,在其他培养基上生长较差。芽管试验、硝酸盐同化试验、糖发酵试验均阴性;厚壁孢子试验、放线菌酮耐受试验阳性;尿素酶试验弱阳性;API20C酵母系统鉴定中葡萄糖、甘油、木糖、山梨醇为阳性,余为阴性。结论PDA、SDA和MEA较适合林生地霉生长;尿素酶试验可作为地霉属属内鉴定的参考依据。API20C鉴定结果及厚壁孢子试验可为其与毛孢子菌属的属间鉴别提供依据。     

掘氏疫霉遗传学研究I．自交后代(S1)生物学性状的遗传与变异

测定了掘氏疫霉Phytophthora drechsleri Tucker生长速率、菌落形态、菌体形态、产孢能力、耐35℃高温生长、致病力等生物学性状在自交S1代的遗传与变异。2个掘氏疫霉野生型菌株(A1、A2各1株)经聚碳膜间隔配对诱导自交产生的卵孢子(保存110天左右)在S+L培养基上萌发,分别获得30和35个单卵孢株(萌发率10％左右)。测定结果表明,上述生物学性状在2个亲本自交后代均发生变异,部分单卵孢株生长速度减慢、菌落形态明显改变、孢子囊和菌丝畸形、产孢能力增强、在35℃中弱生长或不生长,或致病力减弱直至无致病力。在亲本的单游动孢子无性系后代未观察到上述变异,说明上述生物学性状变异主要因亲本遗传因子的杂合性所致。从遗传学角度探讨了在自然条件下掘氏疫霉生物学性状的变异性以及某些分类依据不稳定的原因,指出有性生殖过程中的基因重组可能是引起掘氏疫霉生物学性状变异的主要原因之一。     

掘氏疫霉遗传学研究 Ⅰ.自交后代(S_1)生物学性状的遗传与变异

测定了掘氏疫霉Phytophthora drechsleri Tucker生长速率、菌落形态、菌体形态、产孢能力、耐35℃高温生长、致病力等生物学性状在自交S_1代的遗传与变异。2个掘氏疫霉野生型菌株(A_1、A_2各1株)经聚碳膜间隔配对诱导自交产生的卵孢子(保存110天左右)在S+L培养基上萌发,分别获得30和35个单卵孢株(萌发率10%左右)。测定结果表明,上述生物学性状在2个亲本自交后代均发生变异,部分单卵孢株生长速度减慢、菌落形态明显改变、孢子囊和菌丝畸形、产孢能力增强、在35℃中弱生长或不生长,或致病力减弱直至无致病力。在亲本的单游动孢子无性系后代未观察到上述变异,说明上述生物学性状变异主要因亲本遗传因子的杂合性所致。从遗传学角度探讨了在自然条件下掘氏疫霉生物学性状的变异性以及某些分类依据不稳定的原因,指出有性生殖过程中的基因重组可能是引起掘氏疫霉生物学性状变异的主要原因之一。     

高山被孢霉产花生四烯酸发酵条件的研究

通过一株高山被孢霉M_(20)(Mortierella alpina)产花生四烯酸的摇瓶发酵研究,确定了其最佳发酵培养基组成及最适摇瓶发酵工艺条件。摇瓶实验确定的最佳培养基组成为(g/L):玉米粉水解液葡萄糖150,酵母粉15,KH_2PO_4 3.0,NaNO_3 3.0,MgSO_4·7H_2O 0.5。最佳发酵工艺条件为:初始pH6.5,装液量为50ml/500ml摇瓶,摇床转速150r/min,温度在菌体生长前三天控制在25℃培养,以后调至20℃培养。在此条件下,发酵培养被孢霉的生物量、菌体总油脂及花生四烯酸分别高达35.5g/L、13.2g/L及2.2g/L,在15L及1000L自动机械搅拌罐进行发酵试验,AA产量分别高达1.86g/L及1.70g/L。     

地生弯颈霉的培养与生长条件

从长白山北坡森林土壤中分离纯化得到1株地生弯颈霉(Tolypocladium geodes),对其培养及生长条件(如培养基、光照、温度、碳源、氮源和pH等)进行了试验。结果表明,地生弯颈霉在麦芽浸膏琼脂培养基(MEA)上菌落生长直径最大,马铃薯葡萄糖琼脂培养基(PDA)上产孢量最高;5~30℃温度范围内均能生长,25℃时生长和产孢量最佳;最适碳源和氮源分别为葡萄糖和柠檬酸铵;光暗交替条件下,最利于其生长和产生孢子;pH4~9范围内均能生长和产孢,pH=8时菌落直径最大,pH=6时产孢量最高。     

雪腐镰刀菌烯醇产生菌株的筛选

本文对镰刀菌3个种的47个菌株用豌豆发芽抑制和鸽子呕吐试验筛选雪腐镰刀菌烯醇(Nivalenol)的产生菌株。化学分析的结果表明雪腐镰刀菌M-24和禾谷镰刀菌M-46能够产生雪腐镰刀菌烯醇。菌株M-24适宜的产毒温度为25-30℃;25℃条件下,M-24的产毒高峰出现在接种后的第三、四周,雪腐镰刀菌烯醇的含量分别达到447.9mg/kg和538.0mg/kg;五种培养基上产毒量也有所不同,在大麦和大米上产毒量最高(毒素含量分别为819.7mg/kg和780.5mg/kg),玉米和小麦上次之(521.9mg/kg,402.4mg/kg),绿豆上产毒量最低(167.6mg/kg)。菌株M-46在上述条件下产毒量均低于5mg/kg。     

铁皮石斛软腐病菌终极腐霉生物学特性及其抑菌植物筛选CSCD

开展铁皮石斛软腐病菌终极腐霉(Pythium ultimum)生物学特性及其抑菌植物筛选研究,为铁皮石斛软腐病防治奠定理论基础。采用菌丝生长速率法测定不同中药材水提物对铁皮石斛软腐病菌终极腐霉的抑制作用及其生物学特性。终极腐霉在PDA培养基上菌丝平均生长速度为0.22 cm/h,最适宜的温度为30℃,最适宜的pH在6~7,最适碳源为葡萄糖、可溶性淀粉,最适氮源为酵母浸膏,光照对菌丝生长影响不显著。当水提物浓度为40 mg干样/mL时,丁香和薄荷的抑制率均分别为100%和96.48%。丁香和薄荷水提物具有防治铁皮石斛软腐病的良好应用潜力。     

产漆酶灰色葡萄孢霉培养条件的研究

通过对培养灰色葡萄孢霉（Botrytis cinerea）不同培养基产漆酶酶活力大小的比较,筛选出了产漆酶灰色葡萄孢霉的最佳培养方法。结果表明：灰色葡萄孢霉在蛋白胨5g/L,酵母提取物20 g/L,蔗糖20 g/L,MgSO4 1.5 g/L,CuSO4 0.006 g/L的培养基中生长最好。最佳的培养条件为：pH值4.9,温度25℃,转速100 r/min。     

影响深红酵母和白地霉产生胞外蛋白和多肽的因素

采用白地霉2.498-47在以蛋白胨为氮源发酵时,只在开始pH3.2左右产生胞外蛋白,NH_4~+则无此限制,还有助于胞外多肽的产生。深红酵母2.280胞外蛋白的最大产率约在pH5.8;尿素作唯一氮源效果最好,与蛋白胨合并使用,可产胞外蛋白约800μg/ml。酵母膏对生长和产胞外蛋白很必要,不能用玉米浆和麦芽汁代替。用0.05N NaOH浸洗不同pH和氮源所培养的细胞都能浸出胞内蛋白,接近400μg/ml。发酵产生胞外蛋白自一日后开始,至二日接近最大量,以后逐渐减少。多肽产生起自第二日,五日未达到最大量。两株酵母菌都不表现蛋白酶活性,因此这个现象还不能解释。     

In vitro and In vivo Effects of Some Fungicides against the Chickpea Blight Pathogen, Ascochyta rabiei

The effects of various fungicides on mycelial growth and spore germination of Ascochyta rabiei were determined by incorporating them into potato dextrose agar and measuring colony diameter and observing colony growth and spore germination at 20 ± 2°C. Eight fungicides prevented spore germination of the pathogen at concentrations of 0.125–2 μg/ml, three hindered mycelial growth at 2–4 μg/ml and seven failed to inhibit mycelial growth even at 128 μg/ml. The reference fungicide for the pathogen, chlorothalonil, stopped conidial germination at low rates but did not prevent mycelial growth at 128 μg/ml. Thirteen fungicides were tested against seed infections of the pathogen, and benomyl + thiram, carbendazim and carbendazim + chlorothalonil seed treatments gave more than 85% inhibition on both vacuum‐infiltrated and naturally infected seeds. Coating the seeds with polymers did not increase the effectiveness of fungicides. Three fungicides; (azoxystrobin, chlorothalonil and mancozeb), gave the highest protection in the field but protection decreased with increased inoculum pressure. Addition of humic acid to fungicide suspensions did not affect their performance.     

阔鳞鳞毛蕨孢子的无菌繁殖

以阔鳞鳞毛蕨（Dryopteris championii）成熟孢子为外植体,研究了不同植物生长调节剂及浓度对其孢子萌发、愈伤组织诱导、丛生芽分化及生根的影响。结果表明：1/2MS＋2%蔗糖为孢子萌发最适培养基,20 d后萌发率达65%;诱导愈伤组织的最适培养基为MS＋KT 0.5 mg.L-1＋2,4-D 1 mg.L-1,诱导率达39.8%,愈伤组织为绿色颗粒状;颗粒状愈伤组织在MS＋KT0.2 mg.L-1的培养基中生长出大量丛生芽,转化率可达66.3%;MS＋IAA 0.2 mg.L-1＋NAA 0.2 mg.L-1培养基可有效促进幼孢子体苗生根。     

球子蕨孢子的无菌繁殖

以球子蕨成熟孢子为外植体,研究了不同激素及浓度对其孢子萌发、愈伤组织诱导、丛生芽分化及生根的影响。结果表明：孢子萌发最适培养基为1／2MS＋2％蔗糖,20d后萌发率达55．7％;诱导愈伤组织的最适培养基为MS＋0．5mg·L-1 KT＋0．5mg·L～2,4-D,诱导率达36％,愈伤组织为绿色颗粒状;颗粒状愈伤组织在不添加激素的MS培养基中即可生长出大量丛生芽,转化率可达49．3％;低浓度（0．2mg·L-1）的IAA可有效促进幼孢子体苗生根。     

小麦雪霉叶枯病菌侵染过程的细胞学研究

采用电镜技术研究了小麦雪霉叶枯病菌(Gerlachia nivalis)侵染过程的细胞学特征。电镜观察发现,分生孢子萌发产生的芽管由孢子细胞壁内层延伸而成;病菌侵入寄主体内后,胞间菌丝先在寄主细胞间扩展,随后胞间菌丝侵入坏死的寄主细胞,形成胞内菌丝;胞间菌丝和胞内菌丝在形态结构上无明显差异。在病菌扩展过程中,寄主细胞发生了一系列的病理变化,并最终坏死消解,寄主细胞的变化可能与病菌分泌的毒素有关。     

Host-plant mediated interactions between two aphid species

Three isolates of Isaria fumosoroseus Wize (Hyphomycetes) were cultured on six media composed of differing amounts of chitin, carbon, and nitrogen. The effect of nutrition on growth and virulence was studied by measuring colony growth, spore yield, germination rate, spore-bound protease (Pr₁) and lipase activity, and virulence of inoculum produced by different media against second instars of diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae). Chitin peptone nutrition media resulted in the highest colony growth but spore yields were lowest for this medium, whereas the osmotic stress medium resulted in the lowest colony growth with fewer spores. Highest lipase activity (4.14 µmol/ml/min) was observed for spores produced on high C/N medium for isolate IF28.2, whereas highest Pr1 activity (2.64 µmol/ml/min) was also observed on high C/N medium for isolate IF28.2. A higher rate of Pr1 and lipase activity for all three isolates was observed on low C/N, 2% peptone, and the osmotic stress media. Conidia from nutrient-poor media (2% peptone) proved to be the least virulent for all three isolates with median survival time values of 2.23, 2.05, and 1.79 days for IF32, IF28.2, and IF49, respectively. Median survival time values for the various nutrient media proved to be positively correlated with spore-bound Pr1 and lipase activity, having correlation coefficient values of 0.115 and 0.538, respectively.     

The Effect of Water Activity and the aw Controlling Solute on Spore Germination of Bacillus stearothermophilus

The germination of spores of Bacillus stearothermophilus was studied in nutrient broth in relation to the water activity ( a _w) of the medium, the nature of the a _w controlling solutes glycerol, sucrose, KCl, and NaCl, and temperature. Quantitation of germination was based on the change of the phase-bright spore to phase-dark. Activation of spores was by exposure to 100°C/10 min in a medium of the same composition as that used for germination.
Of the four solutes used, sucrose proved most inhibitory to germination, especially in the upper part of the temperature range 38-75°C, glycerol was the most favourable whereas KCl and NaCl, whose effect was almost identical, occupied an intermediate place. The glycerol effect became more pronounced as the a _w of the medium decreased towards 0.960, becoming inhibitory thereafter.
The solute effect on spore germination followed a pattern that related to the class of solute, i.e. electrolyte or non-electrolyte, and its cell penetration characteristics.
Solute penetration during heat activation and germination was considered as the major germination factor and was associated with the osmoregulation mechanism within the spore proposed recently as the basis of spore dormancy and resistance.     

Use of Epifluorescence Microscopy in Studies of the Germination and Recovery of Thermoactinomycetes

Spore germination and growth of thermoactinomycetes were observed by epifluorescence microscopy. Each of the principal stages in germination was recognized and found to correspond to changes in phase-contrast appearance commonly monitored during endospore germination. The effects of novobiocin and nalidixic acid on germination of Thermoactinomyces vulgaris and T. thalpophilus were studied by using epifluorescence microscopy. Outgrowth but not initiation was inhibited by 100 μg of nalidixic acid per ml and 50 μg of novobiocin per ml. When each of the compounds, at various concentrations, was incorporated into a medium for thermoactinomycete recovery, the antibiotics were found to inhibit colony development. Samples of water and sediment incubated in a growth medium containing novobiocin and selective for thermoactinomycete species were examined by epifluorescence microscopy for total numbers of outgrown spores. Direct viable counts of outgrown spores indicated that the standard plate count enumerated less than 10% of the viable population of thermoactinomycetes.     

Selenium-mediated differential response of β-glucosidase and β-galactosidase of germinatingTrigonella foenum-graecum

β-Glucosidase and β-galactosidase activity profile tested in different seeds during 24 h germination revealed reasonably high levels of activity inVigna radiata, Cicer arietinum, andTrigonella foenum-graecum. In all seeds tested, β-galactosidase activity was, in general, higher than that of β-glucosidase.T. foenum-graecum seedlings exhibited maximal total and specific activities for both the enzymes during 72 h germination. Se supplementation as Na₂SeO₃ up to 0.75 ppm was found to be beneficial to growth and revealed selective enhancement of β-galactosidase activity by 40% at 0.5 ppm Se. The activities of both the enzymes drastically decreased at 1.0 ppm level of Se supplementation. On the contrary, addition of Na₂SeO₃ in vitro up to 1 ppm to the enzyme extracts did not influence these activities. Hydrolytic rates of β-glucosidase in both control and Se-supplemented groups were enhanced by 20% with 0.05M glycerol in the medium and 30% at 0.1M glycerol. The rates were marginally higher in Se-supplemented seedlings than the controls, irrespective of added glycerol in the medium. In contrast, hydrolysis by β-galactosidase showed a trend of decrease in Se-supplemented seedlings compared to the control, when glycerol was present in the medium. Addition of Se in vitro in the assay medium showed no difference in the hydrolytic rate by β-galactosidase when compared to control, while the activity of β-glucosidase declined by 50%. Se-grown seedlings showed an enhancement of transglucosidation rate by 40% in the presence of 0.1M glycerol. The study reveals a differential response to Se among the β-galactosidase and β-glucosidase ofT. foenumgraecum with increase in the levels of β-galactosidase activity.     

Nutrient requirements in germination of conidiospores of Aspergillus niger V. Tieghen

Germination of conidiospores of A. niger was stimulated by the addition of some carbohydrates and nitrogenous compounds to the growth medium. Glucose at 0.5 and 1.0 mg/ml concentrations was the best sugar for germination. Sucrose and fructose were the second best. Glutamic acid and valine were the most effective nitrogenous compounds for the spore germination of the fungus. Glucose, sucrose, and glutamic acid initiated germination within the first 6 h of incubation. When cellobiose, galactose and valine were used germination started after 9 h. With leucine, cysteine and arginine, however, not only the percentage of germination reduced, but also the latent period increased, significantly. A period of 15 h was needed before germination had been started.     

甘肃黑蛋巢抗松梢枯病菌物质的分离纯化及抑菌活性*

采用MS培养基培养甘肃黑蛋巢Cyathus gansuensis,以生测为导向,乙酸乙酯和氯仿从甘肃黑蛋巢MS培养液中萃取出抗菌活性组分。Rp-18反相色谱柱和高效液相色谱仪相结合,从抗菌代谢产物分离纯化出一种抗松梢枯病菌(Sphaeropsis sapinea)的活性物质CXL-I,高效液相色谱检测表明CXL-I为一纯物质。CXL-I对松梢枯病菌的菌丝生长和孢子萌发有较强的抑制活性,当CXL-I浓度为50礸/ml时对菌丝生长抑制率可达80%,对孢子萌发抑制率达95%以上。