稻秸蓝藻混合厌氧发酵沼液及其化学物质对尖孢镰刀菌西瓜专化型生长的影响

研究稻秸与蓝藻(1∶1)混合厌氧发酵的沼液及其微量化学成分对尖孢镰刀菌西瓜专化型(Fusaruim oxysporum f.sp.niveum,FON)的孢子萌发、孢子数量、菌丝生长的影响。结果表明:40%浓度的发酵沼液即可100%抑制孢子萌发,20%浓度的沼液即可达到98.74%的抑制菌体产生孢子,100%浓度的沼液显著抑制气生菌丝的生长;进一步GC-MS分析发现沼液有机物成分中烷类较多,存在微量的四氯化碳(CCl4)、六氯乙烷(C2Cl6)、1,1-二乙氧基乙烷(CH3CH(OCH2CH3)2)3种化学物质;三者都具有显著的抑菌效果,且随浓度的增加而增大,尤其CH3CH(OCH2CH3)2的抑菌效果最好;0.75%浓度的3种化学物质对孢子萌发的抑制率即可达到100%;在培养基中分别加入CCl4、C2Cl6、CH3CH(OCH2CH3)2的浓度为1.00%时,镰刀菌的产孢数量分别降低了5.67%、18.05%、8.72%;培养4d,三者对尖孢镰刀菌西瓜专化型气生菌丝生长的抑制效果均达到90.40%,效果显著。研究表明沼液中确实存在对病原微生物具有明显抑制作用的多种有效的化学成分,可作为防治病原菌的首选药剂。     

月腺大戟根总黄酮对尖孢镰刀菌抑制作用的研究

采用生长速率法和孢子萌发法分别测定月腺大戟根总黄酮对尖孢镰刀菌菌丝生长和分生孢子萌发的抑制率,显微观察总黄酮处理尖孢镰刀菌后菌丝体形态结构的变化,并测定菌丝体相对电导率,菌丝体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性。结果表明:月腺大戟根总黄酮对尖孢镰刀菌菌丝生长和分生孢子萌发均有显著的抑制作用,抑制率随总黄酮浓度增加而增高,20 mg/L时抑制率达100%。总黄酮处理后的尖孢镰刀菌菌丝较细,分支减少,透明度差,液泡数量增多且形成较大的液泡;菌丝体细胞膜透性增加,SOD、CAT活性呈先上升后下降的趋势。以上实验结果可为植物病害生物防治及开发植物源农药方面提供理论依据和实验技术。     

磷和镉对根内球囊霉Glomus intraradices孢子萌发、菌丝生长和外生菌丝内聚磷酸累积的影响

丛枝菌根真菌(AMF)能够显著提高植物对重金属的抗性,菌丝内聚磷酸(Polyphosphate,PolyP)可能参与了这种抗性的形成。试验以Glomus intraradices孢子为试材,对灭菌条件进行了优化,并进一步研究了不同P和Cd2+水平对孢子萌发、菌丝生长、分支和外生菌丝中聚磷酸含量的影响。结果表明,孢子在1%氯胺T+0.02%链霉素+0.01%庆大霉素+1/100(V/V)吐温-20中灭菌5min的效果最好。孢子萌发率、菌丝分支和菌丝长度随着Cd2+浓度的增加不断降低;当Cd2+浓度达到0.1mmol/L时,孢子萌发率降低为0%,表明Glomus intraradices的孢子萌发对Cd2+的耐受极限为0.1mmol/L;1mmol/L的P促进菌丝分支增加,却降低了萌发率,但对菌丝生长没有影响;在培养23d以后,三者基本不再变化。外生菌丝内的聚磷酸含量随着P的升高而增加;在Cd2+胁迫作用下,聚磷酸的含量降低而菌丝密度随着聚磷酸的升高而升高,表明聚磷酸在减弱重金属毒性方面起了重要作用。     

Inhibitory Effects of Turf Pesticides on Bacillus popilliae and the Prevalence of Milky Disease

Fourteen pesticides (fungicides, herbicides, and insecticides) were tested to determine whether they had deleterious effects on the bioinsecticide Bacillus popilliae, the causal agent of milky disease. All of these pesticides reduced levels of spore viability, spore germination, and/or vegetative cell growth when they were tested over a range of concentrations from 0 to 1,000 ppm of active ingredient, and the fungicides had the greatest detrimental effects. As determined by tests in water, the level of spore viability was significantly reduced by chlorothalonil, iprodione, (2,4-dichlorophenoxy)acetic acid plus 2-(2,4-dichlorophenoxy)propionic acid, and 2-[(4-chloro-o-tolyl)oxy]propionic acid plus (2,4-dichlorophenoxy)acetic acid. In tests performed with iprodione, loss of viability was evident at concentrations less than the concentration calculated to result from recommended use. Tests performed in soil demonstrated that triadimefon, chlorothalonil, (2,4-dichlorophenoxy)acetic acid plus 2-(2,4-dichlorophenoxy)propionic acid, and pendimethalin at concentrations resulting from recommended rates of application reduced spore titers. Spore germination did not occur in the continued presence of 2-[(4-chloro-otolyl)oxy]propionic acid plus (2,4-dichlorophenoxy)acetic acid, isofenphos, and chlordane, whereas exposure of spores to triadimefon or pendimethalin for 2 days stimulated germination. The tests to determine effects on spore germination were inconclusive for all other pesticides. Triadimefon, chlorothalonil, iprodione, pendimethalin, and chlorpyrifos at concentrations less than the concentrations recommended for use inhibited vegetative cell growth of B. popilliae, and chlordane at a concentration that was twice the concentration expected to result from the recommended rate of application repressed cell growth. My data support the hypothesis that use of synthetic pesticides can contribute to a low incidence of milky disease in white grubs.     

丁布对小麦赤霉病菌和玉米小斑病菌的抑制作用

采用菌丝生长速率法和孢子萌发试验法检测了抗菌化合物丁布对小麦赤霉病菌和玉米小斑病菌的抑菌作用。结果表明,丁布在PDA培养基中浓度为0.2-1.0 mg/ml时对两种供试病菌的菌丝生长无抑制作用;丁布浓度为0.4-1.0 mg/ml时对两种供试病菌孢子悬浮液中孢子的萌发具有显著抑制作用;1.0 mg/ml丁布药液中培育15h的小麦赤霉病菌和培育5h的玉米小斑病菌的孢子萌发抑制率分别达到100%和83.6%。     

Leaf gas exchange capacity in relation to leaf position on the stem in field grown teak (Tectona grandis L.f.)

Leaf gas exchange patterns in relation to leaf positions on stems were studied in field grown forest tree, teak (Tectona grandis L.f.) during first year growth under intensive culture plantation. Net photosynthetic rates (PN) were low in immature leaves (1-2 from shoot apices), increased basipetally on shoot, peaked in leaves (3rd or 4th leaves from shoot apices) which had recently reached full expansion, and thereafter declined in lower crown leaves. High PN found in fully expanded young leaves was associated with increased dark respiration rate (RD) and high radiation saturation as well as compensating irradiance for PN when compared to those of aged leaves. Intercellular CO2 concentrations (Ci) determined at ambient CO2 concentration and saturating irradiance were apparently low for leaves exhibiting high PN when compared to those of aged leaves. Differences in stomatal conductance (gs) and the rate of transpiration (E) were not apparent between leaves after full expansion. The relationship of PN with Ci recorded for leaves at different positions on stems and under natural ambient CO2 concentrations showed a linear decrease in PN with marked increasing Ci and suggested that increase in mesophyll limitations could cause decline in PN during aging of teak leaves after full expansion. Highly significant positive linear correlation was found between PN and Ci determined at below ambient CO2 concentrations and saturating irradiance for both fully expanded young and aged leaves. The estimate of linear relationship between PN and Ci, often considered as carboxylation efficiency, was higher for fully expanded young leaves characterised by high PN than for aged leaves exhibiting low PN. Hence, the increase in mesophyll limitations or decrease in carboxylation efficiency could explain gradual reduction in photosynthetic potential with leaf age after maturation in teak. This revised version was published online in June 2006 with corrections to the Cover Date.     

人参连作根际土壤中酚酸物质对人参锈腐病菌的化感效应

采用高效液相色谱法对人参连作根际土壤中的酚酸物质进行了分离鉴定,检测发现人参根际土壤中含有没食子酸、水杨酸、3-苯基丙酸、苯甲酸和肉桂酸5种酚酸物质.采用外源添加法研究该5种酚酸物质对人参锈腐病菌的化感效应.结果表明: 5种酚酸对人参锈腐病菌的菌丝生长和孢子萌发都表现出高浓度抑制、低浓度促进的作用.没食子酸、水杨酸和苯甲酸在0.5 mmol·L^-1处理浓度下,3-苯基丙酸和肉桂酸在0.05 mmol·L^-1处理浓度下,均能够显著促进人参锈腐病菌菌丝生长和孢子萌发,并显著加重人参锈腐病病害严重度.     

Leaf gas exchange capacity in relation to leaf position on the stem in field grown teak (Tectona grandis L.f.)

Leaf gas exchange patterns in relation to leaf positions on stems were studied in field grown forest tree, teak (Tectona grandis L.f.) during first year growth under intensive culture plantation. Net photosynthetic rates (PN) were low in immature leaves (1-2 from shoot apices), increased basipetally on shoot, peaked in leaves (3rd or 4th leaves from shoot apices) which had recently reached full expansion, and thereafter declined in lower crown leaves. High PN found in fully expanded young leaves was associated with increased dark respiration rate (RD) and high radiation saturation as well as compensating irradiance for PN when compared to those of aged leaves. Intercellular CO2 concentrations (Ci) determined at ambient CO2 concentration and saturating irradiance were apparently low for leaves exhibiting high PN when compared to those of aged leaves. Differences in stomatal conductance (gs) and the rate of transpiration (E) were not apparent between leaves after full expansion. The relationship of PN with Ci recorded for leaves at different positions on stems and under natural ambient CO2 concentrations showed a linear decrease in PN with marked increasing Ci and suggested that increase in mesophyll limitations could cause decline in PN during aging of teak leaves after full expansion. Highly significant positive linear correlation was found between PN and Ci determined at below ambient CO2 concentrations and saturating irradiance for both fully expanded young and aged leaves. The estimate of linear relationship between PN and Ci, often considered as carboxylation efficiency, was higher for fully expanded young leaves characterised by high PN than for aged leaves exhibiting low PN. Hence, the increase in mesophyll limitations or decrease in carboxylation efficiency could explain gradual reduction in photosynthetic potential with leaf age after maturation in teak.     

Hyphal growth and fragmentation of Penicillium chrysogenum in submerged cultures

A previously derived population model describing the average properties of hyphal elements in submerged cultures of filamentous fungi was revised, and a term for the influence fo spore germination on the average total hyphal length was added. The model was derived from a general balance for the distribution function for the hyphal elements. Based on experimental data and the derived model, simple kinetic expressions for spore germination, tip extension, branching, and hyphal break-up were set up. It is concluded that spore germination can be quantified by three parameters: (1) the time at which spore germination is initiated, (2) the time at which spore germination terminates, and (3) the fraction of viable spores in a spore suspension. The frequency of spore germination can be described with the B-distribution. For growth kinetics it is concluded that the branching frequency is closely correlated with the total hyphal length and that the average tip-extension rate can be described with saturation kinetics with respect to the hyphal length. Finally, the rate of fragmentation is linearly related to the energy input to the bioreactor, and related to the effective hyphal length. (c) 1995 John Wiley & Sons, Inc.     

Survival of Microorganisms in a Simulated Martian Environment: II. Moisture and Oxygen Requirements for Germination of Bacillus cereus and Bacillus subtilis var. niger Spores1

The effects of moisture and oxygen concentration on germination of Bacillus cereus and B. subtilis var. niger spores were investigated in a simulated Martian environment. Less moisture was required for germination than for vegetative growth of both organisms. A daily freeze-thaw cycle lowered moisture requirements for spore germination and vegetative growth of both organisms, as compared with a constant 35 C environment. Oxygen had a synergistic effect by lowing the moisture requirements for vegetative growth, and possibly germination, of both organisms. Oxygen was not required for spore germination of either organism, but was required for vegetative growth of B. subtilis and for sporulation of both organisms.     

茄子根系分泌物中香草醛和肉桂酸对黄萎菌的化感效应

采用室内培养和生物测定的试验方法,研究了不同浓度的香草醛和肉桂酸对黄萎菌（Verticillium dahliae）及茄子种子萌发、幼苗生长的化感效应.结果表明,香草醛和肉桂酸对茄子黄萎菌的化感效应存在差异,表现为所有浓度的肉桂酸都抑制了黄萎菌孢子萌发,当浓度为0.5mmol/L时抑制作用最大;香草醛在浓度为0.1mmol/L时抑制孢子萌发,其余浓度则表现出促进作用.对香草醛和肉桂酸的生物测定结果显示,当浓度为0.1mmol/L时,肉桂酸促进茄子种子萌发和幼苗生长,其余浓度则表现为抑制作用,并且随着浓度的加大抑制作用增强;香草醛在各浓度水平下都促进了茄子种子萌发和幼苗生长,当浓度为0.5mmol/L时促进作用最大.     

高CO2浓度下4种豆科乔木种子萌发和幼苗生长

 本文研究了高CO2浓度(550×10-6±50×10-6)对4种豆科乔木的种子萌发和幼苗生长的影响,结果如下：(1)高CO2浓度能使光叶红豆种子萌发率提高12％,对其它种的萌发没有明显影响。(2)高CO2环境能增加4种幼苗根瘤数量,提高根瘤的固氮活性和根瘤中可溶性糖的含量。(3)在高CO2环境下生长的幼苗叶片净光合速率比对照CO2环境(约350×10-6)下生长的幼苗提高66.7％～105.9％。在高CO2浓度和对照CO2浓度下生长的幼苗,移至相同C02浓度下测定时,光合速率无明显的差异。高CO2环境下生长并测定的幼苗叶片暗呼吸速率和对照CO2浓度下生长并测定的幼苗的测值差异不大,前者较后者低5.58％～l0.55％。(4)在高CO2环境下生长的4种幼苗干物质比对照的增加29.79％～50.30％,根系增加量较大,根冠比略上升。幼苗的相对生长速率和单位叶率上升,而叶面积比率下降。(5)幼苗对高CO2环境的反应和种的生态特性有关。喜光的大叶合欢幼苗对高CO2环境的反应较大,喜光而具一定耐荫性的猴耳环幼苗次之,而耐荫的光叶红豆和茸荚红豆幼苗则较小。     

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。     

Control of Penicillium martensii Development and Penicillic Acid Production by Atmospheric Gases and Temperatures

The effects of various gaseous environments and temperatures on development of Penicillium martensii NRRL 3612 and production of penicillic acid (PA) were determined. Accumulation of PA in mold-inoculated corn was measured following incubation under air; 20% CO(2), 20% O(2), 60% N(2); 40% CO(2), 20% O(2), 40% N(2); and 60% CO(2), 20% O(2), 20% N(2). Although reduced temperature initially inhibited PA production, at the end of the trial the largest quantity of PA (120 mug/g of corn) was found in air-incubated corn at the lowest test temperature (5 C). Atmospheres enriched with 60% CO(2) reduced PA accumulation below a detectable level at 5 and 10 C after a 4-week incubation period. Spore germination tests were carried out in a liquid growth medium incubated for 16 hr under several test conditions. Germ tube outgrowth at 30 C ranged from 36% in air to 2% in 60% CO(2), whereas no germination was observed in CO(2)-enriched gases at 10 C. When spore respiration rates were measured in air and O(2) in a liquid growth medium, complete removal of CO(2) from the reaction atmosphere did not reduce O(2) uptake.     

混合盐碱胁迫对芹菜种子萌发的影响

NaCl、Na2SO4、NaHCO3和Na2CO3按不同比例混合,模拟盐度和pH变化规律与天然盐碱地相似的15种盐碱条件,探讨混合盐碱胁迫对芹菜(Apium graveolens)种子萌发的影响.结果表明:芹菜种子的发芽率、发芽势、发芽指数和活力指数均随盐浓度的升高,pH的增大呈下降趋势.芹菜种子的萌发主要受盐浓度的影响,不同盐浓度间的影响差异大;当盐浓度为200 mmol/L时,基本不萌发.     

变异鳞毛蕨的孢子培养与配子体发育研究

应用无菌培养和常规泥土培养两种方法对变异鳞毛蕨(Dryopteris varia)孢子进行了比较研究,并在光学显微镜下观察了其配子体的发育过程.结果表明:蔗糖浓度为2%的1/2MS与MS培养基对孢子萌发时间和萌发率影响不大,但前者较适于孢子萌发,而后者则适于孢子体形成;在1/2MS培养基上,1%的蔗糖浓度比其它浓度更适宜于孢子的萌发.以菜园士为培养基质时,变异鳞毛蕨孢子的萌发时间短且萌发率高,但幼孢子体出现的时间明显晚于无菌培养.孢子萌发为书带蕨型,原叶体发育为三叉蕨型,符合鳞毛蕨属配子体发育的特征.     

天柱山黄山松种内与种间竞争的研究

研究无菌条件下不同浓度砷对蜈蚣草的孢子萌发、假根和原叶体生长发育的影响。结果表明,培养基质中As浓度大于30mg/L时,孢子萌发速度、假根和原叶体的生长发育受到抑制,假根的着生点位置发生改变;而与高浓度As影响不同的是,低浓度As(30mg/L)可促进孢子变绿的速率和初期原叶体(播后8d内)的生长。因此,高浓度As能抑制配子体生长发育并改变假根着生点位置,而低浓度As则可促进配子体早期的生长。     

Effects of temperature, pH, water activity and CO2 concentration on growth of Rhizopus oligosporus NRRL 2710

AIMS: To investigate the effects of temperature, pH, water activity (aw) and CO2 concentration on the growth of Rhizopus oligosporus NRRL 2710. METHODS AND RESULTS: Hyphal extension rates from mycelial and spore inocula were measured on media with different aw (approximately 1.0, 0.98 and 0.96) and pH (3.5, 5.5 and 7.5) incubated at 30, 37 or 42 degrees C in atmospheres containing 0.03, 12.5 or 25% (v/v) CO2. The effects of environmental conditions on hyphal extension rate were modelled using surface response methodology. The rate of hyphal extension was very sensitive to pH, exhibiting a pronounced optimum at pH 5.5-5.8. The hyphal extension rate was less sensitive to temperature, aw or CO2, exhibiting maximum rates at 42 degrees C, a(w) approximately 1.0 and 0.03% (v/v) CO2. CONCLUSIONS: The fastest hyphal extension rate (1.7 mm h(-1)) was predicted to occur at 42 degrees C, pH 5.85, a(w) approximately 1.0 and 0.03% CO2. SIGNIFICANCE AND IMPACT OF THE STUDY: The present work is the first to model the simultaneous effects of temperature, pH, aw and CO2 concentration on mould growth. The information relates to tempe fermentation and to possible control of the microflora in Tanzanian cassava heap fermentations.     

天然植物提取物对茄子黄萎病菌的抑制活性

以茄子黄萎菌为供试菌种,研究了54种天然植物的乙醇提取液对茄黄萎菌的抑菌活性. 结果表明, 有15种植物提取物对茄子黄萎菌菌丝生长抑制率大于50%,其中细辛、黄连、厚朴、儿茶、苦参、甘草、蛇床子、桔梗、洋葱的提取物对供试菌菌丝生长抑制作用较强,抑制效果均在65%以上,蛇床子的抑菌率达86.84%.有16种植物提取物对病菌孢子萌发的抑制作用大于70%,其中7种植物提取物对孢子萌发的抑制率大于95%以上,细辛、黄连、厚朴基本上抑制了孢子的萌发.儿茶提取物对菌丝生长的抑制效果较差,但却显著抑制了孢子萌发,抑制率达100%.蛇床子提取物虽然抑菌效果较高,但其处理的孢子萌发率为11.3%.研究发现天然植物提取物中存在着抑制黄萎菌的活性物质,这为生物防治黄萎病和进一步研究蔬菜抗病增产理论提供了新的思路与途径.     

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。