外生菌根真菌对植物促生抗逆作用机制研究进展

外生菌根真菌（ECM）为土壤真菌与陆地植物根系形成的一种互惠共生体,是森林生态系统关键的组成部分。作为生态系统的重要组分,外生菌根真菌具有较强的适应能力,可适应干旱、盐碱、重金属污染等逆境条件,外生菌根真菌侵染宿主植物根系可促进宿主植物生长、土壤养分吸收与利用、提高抗逆和抗病能力、改善土壤环境微生物群落结构。林业生产与菌根关系密切,外生菌根真菌是林木生长必不可少的重要组成部分,森林的可持续经营离不开外生菌根真菌,菌根化育苗与造林可显著提高林木成活率、促进苗木对土壤中营养元素的吸收利用和植物生长、提高植物抗逆性。文中系统阐述了外生菌根真菌促进植物生长、增强宿主植物对重金属污染、干旱、盐碱以及病虫害胁迫抗性的机制及生物修复作用,同时对外生菌根真菌资源开发、环境因子对外生菌根真菌资源的影响及利用现代技术深入研究外生菌根真菌作用机制提出了研究建议与展望。     

外生菌根及其在现代林业中的应用

外生菌根(ECM)是真菌菌丝体包围宿主植物尚未木栓化的营养根形成的共生体。菌根真菌广泛的存在于土壤中,具有丰富的多样性。外生菌根不仅能够扩大植物根系的吸收面积,增强植物对矿质元素的吸收能力,促进植物生长,增强植物抗干旱和抗病性的能力,还承担重要的生态功能。随着菌根研究的深入,外生菌根技术也被广泛的应用于现代林业生产中。该文从外生菌根真菌多样性、功能以及在现代林业生产中的应用现状3方面综述了外生菌根的研究和应用现状。     

外生菌根共生体对病原菌拮抗作用机制

针对外生菌根能够增强植物抗病性现象,从外生菌根特殊结构、外生菌根共生体产生化学抑制剂、有保护作用的菌根际微生物群落、增强营养吸收、与病原菌进行营养竞争等几个方面,分析了外生菌根拮抗病原菌的机理,为菌根作为生防手段提供依据。     

VA菌根对植物的有益作用及其应用展望

从VA菌根能扩大宿主植物根的吸收面积,增强矿质营养吸收,提高抗逆性、抗病性等四个方面阐述了对植物的有益作用,展望了VA菌根的应用前景。     

我国南方地区外生菌根真菌研究进展

外生菌根真菌是森林生态系统中关键的微生物组分,在促进植物养分与生长、提高宿主抗逆性、驱动群落演替和促进生物多样性维持等方面发挥着重要作用。本文综述了我国南方地区外生菌根真菌多样性方面的研究进展,该区域中文期刊已报道外生菌根真菌有370种,隶属29科53属,优势科为红菇科(Russulaceae)、牛肝菌科(Boletaceae)和鹅膏菌科(Amanitaceae),优势属为红菇属(Russula)和鹅膏属(Amanita);分析了我国南方外生菌根真菌资源分布及其限制因素的研究进展,提出该区域未来外生菌根真菌研究方向:外生菌根真菌多样性分布格局及其维持机制;外生菌根真菌与相关生物间互作机制;基于外生菌根真菌功能性状的大尺度生态机制研究外生菌根应用技术原理与研发。     

外生菌根共生对林木氮素吸收的促进作用

外生菌根真菌能与某些树木形成稳定的菌植共生体——外生菌根。外生菌根能吸收土壤中植物难以吸收的无机或有机形式营养物质,并传递至宿主植物为其所利用。由于这种养分传递的生态重要性,外生菌根真菌介导的“菌植”N传递关系受到研究人员的广泛关注。文中综述了外生菌根真菌的可利用N形式及其促进宿主植物N营养吸收的机理,主要归纳为:1）菌根增加了养分吸收面积,促进N吸收;2）外生菌根真菌编码利用N源所必需的一套酶和转运体,协助宿主对难吸收的硝酸盐和有机N的利用。在全球N沉降日益加剧的背景下,本综述将有助于了解外生菌根在当前和未来气候情景下的生态作用。     

林木—菌根菌共生体在抗旱造林中的作用机制

鉴于林木—菌根菌共生体在抗旱造林中的作用和应用潜力,从提高水分吸收能力及利用效率、改善植物养分状况、提高植物生长物质合成能力、增强植物生理生化调节能力以及共生体双方的多样性表现对生境的广泛适应性和抗逆性等方面对共生体在抗旱造林中的作用机制进行了简要阐述。     

菌根对植物营养的作用

植物的根与真菌形成菌根,产生互利的共生作用。大多数植物都具有菌根,而不只是根的本身。只有几个科的植物不能形成菌根。菌根一般有三种类型:外生菌根、内生菌根和内外生菌根。侵染根部的真菌对根的影响及其致病作用,现在还只对前两种类型作了研究。森林树种主要形成外生菌根,特别是松科、壳斗科、桦木科、桃金娘科和担子菌纲与子囊菌纲共生的菌根。真菌在根表面形成密集的菌丝覆盖层,并在皮层的细胞间隙生长。与没有菌根的根系比较,有     

菌根对林木生理代谢影响研究进展

菌根作为自然界中最为普遍的一种植物-微生物共生体存在于绝大多数树种的根系中,具有较强的生态适应性和可塑性。在林木菌根形成过程中,菌根真菌参与根系乃至整个林木的生理代谢活动,从而促进林木生长,增强其抗逆性。因此,探究菌根对林木生理代谢的影响及作用机理是林木菌根应用的基础,具有重要的现实意义和科学价值。文中综述了近10余年来国内外有关外生菌根和丛枝菌根对于改善林木碳素营养,促进林木对氮、磷等矿质元素吸收、转运的途径与机制,以及在抗旱性、抗病性、抗重金属等生理代谢方面的研究进展,分析了当前我国林木菌根研究中存在的问题,并对未来研究进行展望,以期为我国林木菌根研究与应用提供参考。     

逆境胁迫下丛枝菌根对茶树生长及茶叶品质的影响

指出了丛枝菌根是植物与丛枝菌根菌的互惠共生体,形成菌根的茶树,其养分吸收能力与抗逆性均能得到显著的提高。介绍了盐分胁迫与铅胁迫对茶树生长及茶叶品质的影响,提出了丛枝菌根在盐分胁迫与铅胁迫对茶树生长及茶叶品质的影响,分析了丛枝菌根缓解盐分胁迫和重金属胁迫的的作用机理,以期为丛枝菌根菌在茶树的大面积应用提供理论基础。     

毛白杨优良外生菌根菌的选择*

在毛白杨外生菌根菌生态学特性和共生关系研究的基础上，对与毛白杨有良好共生关系的外个菌根菌的研究表明，硬皮马勃能耐温，在碱笥条件下仍能生长，在中性基质中，均能与毛白杨形成菌根，并大幅度地提高毛白杨的生长量。但在碱性土壤中，仅有硬皮马勃能与毛白杨形成一定数量的菌根，并能明显地提高毛白杨的生长量、地上部分生物量，改善菌木Ｎ、Ｐ的营养状况，接种效果随接种量的变化而差异明显。     

Prior contact of <Emphasis Type="Italic">Pinus tabulaeformis</Emphasis> with ectomycorrhizal fungi increases plant growth and survival from damping-off

Pinus tabulaeformis (Chinese pine) is a widely planted conifer species in northern China and is used for soil and water conservation on the Loess Plateau. Due to its strong reliance on ectomycorrhizae and low survival rate from damping-off during seedling cultivation and in nurseries, we explored the early influence of three ectomycorrhizal fungi (Handkea utriformis, Suillus lactifluus, and Suillus tomentosus) on the growth, root morphological characters, root vitality, and survival of P. tabulaeformis seedlings from subsequent damping-off in a pot experiment. In addition, the in vitro suppression of three ectomycorrhizal fungi on the damping-off pathogen (Fusarium solani) was evaluated and observed using a scanning electron microscope. We found that all three ectomycorrhizal fungi could colonize more than 40% of the roots of P. tabulaeformis, promote plant shoot and root growth, increase the proportion of large-diameter roots, improve root vitality, and increase survival rates 3 months after inoculation. All three ectomycorrhizal fungi suppressed the growth of F. solani to a different extent in vitro. Ectomycorrhizal fungal hyphae proliferated and wrapped around the hyphae of F. solani when the hyphae encountered each other. The colonization rate of P. tabulaeformis roots was highly correlated with root vitality and root growth parameters, while the survival rate of P. tabulaeformis seedlings was highly correlated with the colonization rate of P. tabulaeformis roots, root vitality and growth. Our results suggest that early contact between P. tabulaeformis and ectomycorrhizal fungi could improve plant growth and resistance against damping-off.     

Weed management and irrigation are key treatments in emerging black truffle (Tuber melanosporum) cultivation

Interest in conversion of marginal agricultural lands to small oak woodlands for the production of black truffles (Tuber melanosporum Vittad.) is increasing in the native black truffle areas of France, Spain and Italy as well as suitable or amended sites throughout the world due to high economic returns for gastronomically valuable truffles. Successful long-term management of a perennial plantation replacing an annual crop requires understanding the system in all phases of the life cycle, and in the case of truffles this involves understanding the interactive growth of the aboveground host and the belowground symbiotic ectomycorrhizal fungus whose fruitbody is the desired truffle. Here we focus on the pre-production phase, 4 years after establishing the truffle-oak plantation and prior to truffle production. We tested the influence of weed control, irrigation and fertilizer, each at 3 levels, on plant growth and ectomycorrhizal proliferation in three truffle-oaks plantations in northeast Spain. Results show that adequate weed control improves root and shoot dry weight while fertilizer and irrigation treatments did not influence plant growth. The low dose of irrigation (50% of the estimated water deficit for the site) and glyphosate weed control both increased total root tips/plant and T. melanosporum colonized tips (ectomycorrhizae) by approximately two-fold, compared to control treatments. Distribution of the ectomycorrhizae within the soil profile was significantly influenced by the low dose irrigation treatment, with increases observed in the 10?C20 cm and the 20?C30 cm deep layers compared to the control and high irrigation treatments. Four years after planting, T. melanosporum remained the dominant fungal symbiont, despite the presence of 14 other ectomycorrhizal morphotypes from these sites.     

Ectomycorrhizae Reduce Damage to Russian Larch by Otiorhyncus Larvae

The effect of ectomycorrhizae on damage caused by Otiorhyncus larvae and on plant growth was evaluated in a 3-yr field experiment. Russian larch seedlings, inoculated with ectomycorrhizal fungi, were compared with uninoculated plants. Assessment of larval damage at the end of the first growing season showed a significant effect of treatment on damage intensity, but not on damage incidence: 11.2% of uninoculated seedlings were severely damaged, but only 3.5% of inoculated plants. There was a significant effect of treatment on plant mortality. The accumulated mortality at the end of the third growing season was 34.5% for uninoculated plants, but 17.6% for inoculated plants. The height increment of inoculated plants (4.5 cm) was significantly greater than that of uninoculated plants (2.7 cm) in the first growing season. No difference in height increment between treatments was observed during the second and third growing seasons.     

毛白杨VA菌根与外生菌根关系的研究

定期从毛白杨扦插育苗地挖取根样，并从中原地区的毛白杨人工林地采集细根（直径小于２ｍｍ）根样，观察统计ＶＡ菌根、外生菌根、混合菌根以及未受菌根菌侵染的１ｃｍ长根段的百分比。结果表明，在苗木的菌根侵染初期，ＶＡ菌根菌的侵染势较强，但优势很快被外生菌根菌取代，两种菌根菌间的负交互作用随苗龄的增加而不断增强。造林地种类和土壤的ｐＨ值对毛白杨两种菌根间的负交互作用关系有制约作用。在强碱性砂土地上，ＶＡ菌根的     

Elevated atmospheric CO(2) concentration changes ectomycorrhizal morphotype assemblages in Betula papyrifera

Ectomycorrhizae are extremely diverse, with different species of fungi having very different physiologies and morphologies that, in turn, confer a range of different benefits to the host plant. To test the hypothesis that elevated CO(2) leads to changes in the assemblage of ectomycorrhizae associated with trees, we examined the number and frequency of ectomycorrhizal morphotypes colonizing roots of Betula papyrifera Marsh. saplings grown at an ambient or elevated (700 ppm) atmospheric CO(2) concentration for 24 weeks. Elevated CO(2) resulted in significant changes in the composition of the ectomycorrhizal assemblage toward morphotypes with a higher incidence of emanating hyphae and rhizomorphs. We conclude that B. papyrifera saplings will be able to support a more costly mycorrhization in future elevated-CO(2) atmospheres.     

杨树菌根研究进展

杨树菌根真菌资源丰富，有３０种外生菌根真菌和５种ＶＡ菌根真菌可与其共生形成外生菌根和ＶＡ菌根，菌根的形态和解剖特征与菌根真菌的种类有关。菌根可以促进杨树苗木养分和水分的吸收，提高苗木的生长量，增强其抗旱性，并且可以诱导杨树体内酚类物质代谢中酶类（ＰＯ、ＰＰＯ、ＰＡＬ等）活性的提高，加速抗病性物质（酚类等）的合成，增强杨树抗溃疡病的能力     

Effects of arbuscular mycorrhizal fungi on leaf solutes and root absorption areas of trifoliate orange seedlings under water stress conditions

The effects of the arbuscular mycorrhizal (AM) fungus Glomus mosseae on plant growth, leaf solutes and root absorption area of trifoliate orange (Poncirus trifoliata (L.) Raf.) seedlings were studied in potted culture under water stress conditions. Inoculation with G. mosseae increased plant height, stem diameter, leaf area, shoot dry weight, root dry weight and plant dry weight, when the soil water content was 20%, 16% and 12%. AM inoculation also promoted the active and total absorption area of root system and absorption of phosphorus from the rhizosphere, enhanced the content of soluble sugar in leaves and roots, and reduced proline content in leaves. AM seedings had higher plant water use efficiency and higher drought tolerance than non-AM seedlings. Effects of G. mosseae inoculation on trifoliate orange seedlings under 20% and 16% soil water content were more significant than under 12% soil water content. AM infection was severely restrained by 12% soil water content. Thus, effects of AM fungi on plants were probably positively related to the extent of root colonization by AM fungi. The mechanism of AM fungi in enhancing drought resistance of host plants ascribed to greater osmotic adjustment and greater absorption area of root system by AM colonization. __________ Translated from Journal of Plant Physiology and Molecular Biology, 2005, 30(5): 583–588 [译自: 植物生理与分子生物学报, 2005, 30(5): 583–588]