银杏根系甲醇溶提物对离体培养条件下丛枝菌根真菌生长发育的研究

银杏根系甲醇溶提物对离体培养条件下丛枝菌根真菌生长发育的试验结果表明,银杏根系甲醇溶提物对离体条件下丛枝菌根真菌(Glonus mosseae,Gigaspora margarita)生长发育有明显的促进作用,能显著提高孢子萌发率,增加菌丝生长长度。与对照相比,浓度为20％～100％的甲醇溶提物均可显著促进丛枝菌根真菌的生长发育,80％甲醇溶提物效果最明显,银杏根系甲醇溶提物中含丰富的黄酮类化合物,溶提物中黄酮类物质的含量与甲醇洗脱剂的浓度有关,当浓度为80％时,黄酮含量最高,对银杏根系甲醇溶提物中黄酮类化合物含量与丛枝菌根真菌生长发育相关性分析发现,溶提物中黄酮类化合物含量与离体条件下丛枝菌根真菌孢子的生长发育表现为极显著的正相关关系,溶提物中黄酮含量越高,其对丛枝菌根真菌孢子的生长发育促进作用越大。     

澳洲坚果根系溶提物对AM真菌孢子萌发和菌丝生长的影响

澳洲坚果(Macadamia integrifolia)根系甲醇溶提物影响离体培养条件下丛枝菌根真菌孢子生长发育的试验结果表明,澳洲坚果根系甲醇溶提物对离体条件下丛枝菌根真菌(Glomus mosseae和Gigaspora margarita)孢子生长发育有明显的促进作用,能显著提高孢子萌发率,增加菌丝长度。浓度为20%~100%的甲醇溶提物均可显著促进丛枝菌根真菌孢子的生长发育,其孢子萌发率和菌丝长度均显著高于对照,60%的甲醇溶提物效果最明显。Glomus mosseae和Gigaspora margarita孢子萌发率随着甲醇溶提物浓度的升高而增加,60%甲醇溶提物孢子萌发率达到最高,分别为81.7%和76.0%。Glomus mosseae和Gigaspora margarita孢子菌丝长度也表现为随洗脱剂浓度的升高,菌丝生长呈先增强后减弱趋势,洗脱剂浓度为60%时菌丝长度达最长,分别为31.2和28.0 mm。澳洲坚果根系甲醇溶提物中含丰富的黄酮类物质,其含量与甲醇洗脱剂的浓度有关,当浓度为60%时,黄酮类物质含量最高。通过对澳洲坚果根系甲醇溶提物中黄酮类物质含量与丛枝菌根真菌孢子生长发育的相关性分析发现,甲醇溶提物中黄酮类物质含量与离体条件下丛枝菌根真菌孢子的生长发育表现为极显著的正相关。甲醇溶提物中黄酮类物质含量越高,其对丛枝菌根真菌孢子的生长发育促进作用越大。     

西双版纳热带雨林中丛枝菌根真菌的初步研究*

对西双版纳热带雨林中30个科的42种植物根系的丛枝菌根真菌定居情况进行了调查,并从这些植物的根际土壤中分离鉴定了分属于无梗囊霉属(Acaulospora)、球囊霉属(Glomus)和硬囊霉属(Sclerocystis)的25种丛枝菌根真菌。对热带雨林土壤中丛枝菌根真菌的孢子密度（spore density）、物种丰富度（species richness）以及已鉴定种的出现频率进行统计分析发现：热带雨林土壤中丛枝菌根真菌的孢子密度在每100g土壤116~1560个之间,平均478个;物种丰富度在2~7之间,平均为4.5;无梗囊霉属和球囊霉属真菌是热带雨林土壤中丛枝菌根真菌的优势类群。     

菌根真菌提高蓝莓抗逆性研究进展

杜鹃花类菌根真菌和丛枝菌根真菌对蓝莓Vaccinium spp.的生长发育和抗逆性等方面具有重要促进作用。本文结合国内外研究进展,从蓝莓产业发展现状、蓝莓与菌根真菌特性、菌根真菌对蓝莓抗逆性的影响等方面进行综述,并对菌根真菌提高蓝莓抗逆性的研究方向进行展望。     

营养液强度对AM真菌生长发育的影响*

研究了在贫营养基质中不同强度Hoagland营养液对丛枝菌根(Arbuscular mycorrhizae, M)真菌Glomus versiforme生长发育的影响。结果表明:本试验条件下,菌根侵染率、菌丝量、孢子数间呈显著正相关。在施加5%~50%强度Hoagland营养液时, 菌根真菌的生长与宿主植物高粱根中磷浓度、可溶性糖浓度密切相关,而与氮浓度无显著相关。由此认为:在盆栽生产菌根菌剂时,基质中存在一个临界磷浓度,在这个临界浓度之下,菌根真菌的生长发育随磷浓度的提高而增长,超过该临界浓度则会随磷浓度的提高而下降。施用20%、50%强度Hoagland营养液对菌根真菌生长最为有利,其菌根侵染率、菌丝量、孢子数均高于其它处理,因此认为:宿主植物—菌根真菌之间共生关系的基础是营养条件,基质中养分的高低会影响互惠共生关系的建立和发展。在高质量菌剂生产中, 菌根共生体双方的生长发育完全可以由人工控制。施加营养液是一种有效的调控手段,有可能使共生平衡向有利于菌根真菌生长发育的方向倾斜,使真菌得到最大程度的生长。     

矿区分离丛枝菌根真菌对万寿菊吸Cd潜力影响

盆栽试验研究土壤不同施Cd水平(0、5、20、50μg/g)下,接种矿区污染土壤中丛枝菌根真菌对万寿菊根系侵染率、植株生物量及Cd吸收与分配的影响。结果表明:接种丛枝菌根真菌显著提高Cd胁迫下万寿菊的根系侵染率和植株生物量;随着施Cd水平提高,各处理植株Cd浓度显著增加。各施Cd水平下万寿菊地上部Cd吸收量远远高于根系Cd吸收量,在土壤施Cd量达到50μg/g时,接种处理地上部Cd吸收量是根系的3.48倍,对照处理地上部Cd吸收量是根系的1.67倍;同一施Cd水平下接种处理植株Cd吸收量要显著高于对照。总体上,试验条件下污染土壤中分离的丛枝菌根真菌促进了万寿菊对土壤中Cd的吸收,并在一定程度上增加Cd向地上部分的运转,表现出植物提取的应用潜力。     

营养液强度对AM真菌生长发育的影响

研究了在贫营养基质中不同强度 Hoagland 营养液对丛枝菌根(Arbuscular mycorrhizae,M) 真菌 Glomus versiforme 生长发育的影响。结果表明：本试验条件下,菌根侵染率、菌丝量、孢子数间呈显著正相关。在施加5％～50％强度。Hoagland 营养液时,菌根真菌的生长与宿主植物高粱根中磷浓度、可溶性糖浓度密切相关,而与氮浓度无显著相关。由此认为：在盆栽生产菌根菌剂时,基质中存在一个临界磷浓度,在这个临界浓度之下,菌根真菌的生长发育随磷浓度的提高而增长,超过该临界浓度则会随磷浓度的提高而下降。施用20％、50％强度 Hoagland 营养液对菌根真菌生长最为有利,其菌根侵染率、菌丝量、孢子数均高于其它处理,因此认为：宿主植物一菌根真菌之间共生关系的基础是营养条件,基质中养分的高低会影响互惠共生关系的建立和发展。在高质量菌剂生产中,菌根共生体双方的生长发育完全可以由人工控制。施加营养液是一种有效的调控手段,有可能使共生平衡向有利于菌根真菌生长发育的方向倾斜,使真菌得到最大程度的生长。     

营养液强度对AM真菌生长发育的影响

研究了在贫营养基质中不同强度Hoagland营养液对丛枝菌根(Arbuscularmycorrhizae,M)真菌Glomus versiforme生长发育的影响.结果表明本试验条件下,菌根侵染率、菌丝量、孢子数间呈显著正相关.在施加5%～50%强度Hoagland营养液时,菌根真菌的生长与宿主植物高粱根中磷浓度、可溶性糖浓度密切相关,而与氮浓度无显著相关.由此认为在盆栽生产菌根菌剂时,基质中存在一个临界磷浓度,在这个临界浓度之下,菌根真菌的生长发育随磷浓度的提高而增长,超过该临界浓度则会随磷浓度的提高而下降.施用20%、50%强度Hoagland营养液对菌根真菌生长最为有利,其菌根侵染率、菌丝量、孢子数均高于其它处理,因此认为宿主植物-菌根真菌之间共生关系的基础是营养条件,基质中养分的高低会影响互惠共生关系的建立和发展.在高质量菌剂生产中,菌根共生体双方的生长发育完全可以由人工控制.施加营养液是一种有效的调控手段,有可能使共生平衡向有利于菌根真菌生长发育的方向倾斜,使真菌得到最大程度的生长.     

接种微生物对大豆生长及其根际土壤的影响

对沙土中的大豆接种丛枝菌根真菌及丛枝菌根真菌与解磷菌和根瘤菌联合接种, 动态监测大豆的生长状况和营养吸收情况。结果表明, 在沙土中, 根瘤菌与丛枝菌根真菌的组合效应对豆科植物营养元素的改善最为有效。接种丛枝菌根真菌以及丛枝菌根真菌与其他微生物联合应用对宿主矿质营养吸收尤其是磷吸收有明显的促进作用, 种植30 d、45 d 和64 d 接菌处理植物叶片的平均全磷含量比对照分别高1.45%、73%和56%。接种微生物使植物从土壤中吸收氮、磷、钾元素的强度比对照高, 接菌植物根际土壤养分浓度低于对照。接菌植物生物量显著高于对照, 单接种丛枝菌根真菌处理、双接种丛枝菌根真菌与解磷菌、双接种丛枝菌根真菌与根瘤菌以及丛枝菌根真菌、解磷菌与根瘤菌三种菌剂混合处理的总生物量分别比对照高出181%、134%、153%和89%。丛枝菌根真菌与解磷菌和根瘤菌三种菌剂混合接种对植物的促生作用并不明显。     

脱落酸对丛枝菌根真菌侵染和产孢的调控效应研究

【目的】揭示脱落酸(ABA)对丛枝菌根(AM)真菌侵染和产孢的影响,建立利用外源ABA促进孢子产量的高效菌剂扩繁方法。【方法】利用番茄毛状根和AM真菌Rhizophagus irregularis DAOM 197198建立双重培养体系,通过外源施用ABA、赤霉素(GA)或者使用ABA、GA的缺陷突变体,染色观察菌根侵染,荧光定量PCR测定丛枝发育和脂质合成运输相关基因的表达,统计丛枝和孢子的数量,从而揭示ABA对AM真菌侵染和产孢的影响。【结果】ABA缺陷突变体not中的F%(侵染频率)、a%(丛枝丰度)、丛枝数量,以及丛枝发育特异性相关基因EXO70A1-like (LOC101253481)、脂质合成运输相关基因RAM2和STR2的表达均显著低于其野生型MT;外源施用ABA显著促进了F%、M%(侵染强度)、丛枝数量、孢子产量,以及脂质合成运输相关基因RAM2和STR2的表达,外源添加ABA处理的孢子产量约为不添加处理的4.5倍;外源GA处理极显著抑制了菌根侵染的所有指标和孢子产量;GA缺陷突变体gib3与其野生型MM的AM真菌侵染之间没有显著差异,但gib3的孢子产量显著高于MM。【结论】ABA通过促进脂质的合成和运输,提高AM真菌的侵染和丛枝形成,进而增加AM真菌的孢子产量。     

Effect of onion (Allium cepa) root exudates on the hyphal growth of Gigaspora margarita

 The effect of root exudates from onions differing in P status on spore germination and hyphal growth of arbuscular mycorrhizal fungi was investigated. Onion (Allium cepa) was grown in solution culture at different phosphorus concentrations (0, 0.1, 1.0, 8.0 and 24.0 mg P l^–1) and root exudates were collected. When spores of the arbuscular mycorrhizal fungus, Gigaspora margarita were incubated with these root exudates, spore germination was only slightly affected but hyphal growth was greatly affected, particularly with exudates from P-deficient plants. This suggests that the P nutrition of host plants influences the composition of root exudates and thereby the hyphal growth of arbuscular mycorrhizal fungi. Accepted: 25 June 1995     

Effect of the fungicide benomyl on spore germination and hyphal length of the arbuscular mycorrhizal fungus Glomus mosseae.

The fungicide benomyl inhibited spore germination and hyphal length of the arbuscular mycorrhizal fungus Glomus mosseae when applied at doses of 21.25 microg/ml (agronomic dose), 10.62 microg/ml and 10 microg/ml. G. mosseae was able to germinate in the presence of 2.12 microg/ml of benomyl, and the percentage of spore germination was unaffected by dosis of 0.1, 0.01 and 0.001 microg/ml of the fungicide. However, all doses of fungicide tested in this study decreased the hyphal length. When ungerminated G. mosseae spores previously exposed to benomyl were transferred to water-agar medium without benomyl, the maximum germination was 16%. Small spores of G. mosseae were more resistant to benomyl than the larger ones. Our results show some of the factors which can explain the variability of the effect of benomyl on arbuscular mycorrhizal fungi.     

丛枝菌根真菌离体培养研究概况(综述)

本文综述丛枝菌根真菌在离体条件下的生长发育、生长促进物质及生理生化代谢等方面的研究概况。     

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。     

毛乌素沙地克隆植物沙鞭生长对AM真菌生态分布的影响

从毛乌素沙地沙鞭群落间隔空地沙鞭根状茎延伸方向设置样地,2007年5月、7月和10月在0-10、10-20、20-30、30-40和40-50 cm共5个土层分别采集土壤样品,研究了AM真菌时空分布及沙鞭侵入间隔空地前后对AM真菌分布的影响。结果表明,沙鞭能与AM真菌形成良好共生关系,菌根结构为中间型(I-型),AM真菌定殖率和孢子密度有明显的时空分布规律,并与土壤因子密切相关。随采样时间后延AM真菌定殖率先增后降,最大值出现在7月份;孢子密度先降后增,最大值出现在10月份。土壤采样深度对AM真菌定殖和孢子密度有显著影响,AM真菌最高定殖率和最大孢子密度均出现在0-20 cm浅土层。孢子密度仅与泡囊定殖率显著正相关。土壤速效N与菌丝和总定殖率极显著负相关;土壤温度与泡囊、丛枝、菌丝和总定殖率显著和极显著正相关,与孢子密度显著负相关;土壤湿度与丛枝、菌丝和总定殖率显著正相关,与孢子密度显著负相关。克隆植物沙鞭的生长对土壤AM真菌活动和分布有很大影响,沙鞭入侵前后样地中AM真菌孢子密度和定殖率变化显著。     

Status of nuclear division in arbuscular mycorrhizal fungi during in vitro development

Summary The number of nuclei in spores and along hyphae of an arbuscular mycorrhizal fungiGigaspora margarita was measured in digital images of fluorescence arising from mithramycin stained cultures. Typical dormant spores (250 m diameter) contained 2000 nuclei. Eight hundred nuclei were mobilized during the first 3 days of germination. The number of nuclei in the spores nearly returned to the initial number after 22 days of hyphal growth. The average relative DNA content in the nuclei of dormant spores and in the nuclei of spores incubated for 22 days was comparable, as judged from fluorescence intensity. Hyphal elongation occurred with 460 nuclei per cm under a special set of in vitro conditions that promote extensive hyphal growth of arbuscular mycorrhizal fungi. We found an average total of 26000 hyphal nuclei per germinating spore after 22 days. The specific DNA polymerase inhibitor aphidicolin did not inhibit spore germination but it rapidly reduced the rate of hyphal growth and arrested growth after 4 days. No nuclei were produced de novo during this time. These results demonstrate thatG. margarita replicates nuclear DNA and undergoes nuclear division when grown in vitro even in the absence of a plant host.     

Impact of Bacillus subtilis JA, a biocontrol strain of fungal plant pathogens, on arbuscular mycorrhiza formation in Zea mays

Summary  In the present study, the influence of Bacillus subtilis JA on arbuscular mycorrhizal fungi (AMF) was evaluated by either pot culture or in vitro conditions, respectively. Under the pot culture conditions, the inoculation of B. subtilis JA decreased the frequency (% F) of the root colonization by indigenous arbuscular mycorrhizal fungi and the shoot dry weight of maize (Zea mays L.), but had no apparent effect on the intensity (% I) of AM fungal root colonization. The unknown volatile emitted from the B. subtilis JA in vitro significantly inhibited spore germination and the hyphal growth in the dual-compartment experiments. Moreover, the data from the direct interaction between B. subtilis JA and Glomus etunicatum showed that soluble antifungal lipopeptides influenced the development of AMF. Therefore, the application of antifungal Bacillus strains should take the compatibility with the indigenous beneficial fungi into consideration.     

Flavonoids exclusively present in mycorrhizal roots of white clover exhibit a different effect on arbuscular mycorrhizal fungi than flavonoids exclusively present in non-mycorrhizal roots of white clover

Abstract

The flavonoids 5,6,7,8,9-hydroxy chalcone, 3,7-hydroxy-4′methoxy flavone, 5,6,7,8-hydroxy-4′-methoxy flavone and 3,5,6,7,4′-hydroxy flavone can be detected only in non-mycorrhizal roots of white clover, but not in mycorrhizal roots, whereas the flavonoids acacetin, quercetin and rhamnetin are only present in mycorrhizal roots. We tested the effect of several concentrations of these compounds on spore germination, hyphal growth, hyphal branching, formation of clusters of auxiliary cells and of secondary spores of the arbuscular mycorrhizal fungi Gigaspora rosea, Gigaspora margarita, Glomus mosseae and Glomus intraradices. Our results indicate that depending on the flavonoid, the tested compounds are involved at different stages in the regulation of mycorrhization. This hypothesis is strengthened by their differing effect on several AM fungal growth parameters. Furthermore, our study provides more data on the AM fungus genus/species specificity of flavonoids.     

Polyamines stimulate hyphal branching and infection in the early stage of <Emphasis Type="Italic">Glomus etunicatum</Emphasis> colonization

Polyamines are known to strongly stimulate hyphal growth in arbuscular mycorrhizal fungi. The effect of the polyamines putrescine, spermidine and spermine on spore germination, hyphal elongation and branching by the AM fungus Glomus etunicatum was investigated in this study. The effect of spermine on infection and the development of the host and of daughter spores was further investigated using the dual monoaxenic culture system comprised of Gl. etunicatum fungal cultures in Ri T-DNA transformed carrot hairy roots. Spermidine and spermine showed positive effects on germination and all three polyamines significantly promoted hyphal growth. Hyphal branching was also strongly stimulated by treatment with polyamines, such as an increase in the number of branches. Infection during the early stages of the in vitro co-culture life cycle was enhanced in the presence of spermine, and daughter spores appeared at earlier timepoints compared to the control. Our results demonstrate that polyamines stimulate germination and hyphal branching in the early stage of AM fungal colonization. Moreover, results from the investigations conducted in the fungus-root co-culture suggest that polyamines may be involved in establishing the symbiotic relationship between root and fungus.