兰科植物菌根真菌的研究进展

兰科（Orehidaceae）是仅次于菊科（Composltae）的一个兴盛、复杂的植物类群,广布于全球,多数种是著名的药用植物和珍贵花卉。兰科植物具有三大特点：第一、其花形状奇特,色彩艳丽,芳香宜人,授粉机制独特而复杂;第二、种子细小,仅具未分化的原胚;第三、在生活史中,与真菌共生形成内生苗根。因而,长期以来受到人们的普遍喜爱,带来了较高的商业利益,科学家,园艺工作者也从各个角度对兰科植物作了大量的研究。本文从兰科菌根的共生物之———菌根真菌的角度对有关其分类及与植物之间的专一性的研究状况进行了分析讨论,旨在为从…     

兰科菌根真菌研究方法的概述

兰科植物资源在全球分布广泛,其中有许多是重要的药用植物和名贵的珍稀花卉,由于具有较高的商业价值,受到各界人士的广泛关注。兰科植物生长习性的特殊性导致其在自然状态下繁殖率极低,因此难以满足市场的广泛需求。近年研究表明,几乎所有兰科植物都能与相应的菌根真菌建立共生关系,并且必须依赖于这些内生真菌才能完成其整个生活史。因而对菌根真菌在提高兰科植物生长速度和繁殖能力过程中机制的研究以及将研究成果运用于工业化育苗中将是缓解兰科植物市场供求紧张问题的关键。通过对近几年有关天麻和铁皮石斛等兰科植物的问题研究中所采用的研究方法加以阐述,以期对今后兰科菌根真菌的研究提供一定的参考。     

密花石斛等六种兰科植物菌根的显微结构研究

本文对密花石斛等六种兰科植物根的显微结构进行了比较观察。结果表明,它们具有典型的兰科植物根,具根被和发达的皮层组织,皮层细胞内分布有针状结晶和菌根真菌形成的菌丝结,发现菌根真菌通过外皮层薄壁通道细胞或破坏根被组织和外皮层细胞侵入皮层细胞,形态内生菌根。     

密花石斛等六种兰科植物菌根的显微结构研究

本文对密花石斛等六种兰科植物根的显微结构进行了比较观察。结果表明,它们具有典型的兰科植物根,具根被和发达的皮层组织,皮层细胞内分布有针状结晶和菌根真菌形成的菌丝结,发现菌根真菌通过外皮层薄壁通道细胞或破坏根被组织和外皮层细胞侵入皮层细胞,形成内生菌根。     

兰科菌根的生态学研究进展

兰科植物(Orchidaceae)是典型的菌根植物,自然条件下其种子的成功萌发和生长的早期阶段对菌根真菌有绝对的依赖性,在有些成年兰科植物中菌根真菌仍起着重要的作用。目前大部分兰科植物已为濒危物种,鉴于兰科植物天然的菌根共生关系,开展兰科植物和菌根真菌互作的生态学研究不仅具有极高的科研价值,更有助于兰科植物的物种保护和野生种群的生态恢复。近年研究表明,兰科植物对真菌的选择和二者共生关系的建立与菌根真菌的空间分布和丰度密切相关,然而当前对自然环境中兰科菌根真菌的实际分布还了解甚少,因此文章从生态学角度系统分析兰科植物与菌根真菌的关系,探讨该领域的研究热点,旨在为兰科菌根的生态学研究提供参考。     

兰科植物菌根真菌研究新见解

兰科(Orchidaceae)在地球生命系统演化中占有十分重要的地位,几乎全部兰科植物均处于不同程度的濒危状态,研究兰科菌根真菌对于保护珍稀濒危兰科植物具有重要意义.该文在对菌根真菌相关的概念及研究方法进行综述的基础上,对兰科菌根真菌的主要类群、特异性及其与兰科植物稀有性之间的关系,以及兰科菌根真菌与兰科植物之间的营养...     

四川黄龙沟优势兰科植物菌根真菌多样性及其季节变化

在自然条件下,兰科菌根真菌对兰花的种子萌发和植株生长都是必不可少的。为了解高原兰科植物菌根真菌的多样性状况及其季节性变化规律,选取了四川黄龙沟的两种生境中生长的8种优势兰科植物,分别于植株的萌芽期(4月份)、生长期(7月份)和果期(9月份)采集营养根进行菌根真菌的多样性研究。其中,黄花杓兰(Cypripedium flavum)、少花鹤顶兰(Phaiusdelavayi)、二叶匍茎兰(Galearis diantha)和广布小蝶兰(Ponerorchis chusua)分布在开阔生境;筒距兰(Tipularia szechuanica)、小花舌唇兰(Platanthera minutiflora)、珊瑚兰(Corallorhiza trifida)和尖唇鸟巢兰(Neottia acuminate)则分布在密林生境。通过对分离所得的50个菌株进行形态观察和ITS序列测定相结合的鉴定,共获得菌根真菌41种。对担子菌和子囊菌分别进行的系统发育树构建结果显示,子囊菌为优势种类(35种),以柔膜菌目(Helotiales)、炭角菌目(Xylariales)和肉座菌目(Hypocreales)内的种类为主,担子菌则以胶膜菌(Tulasnellaceaesp.)为主。在8种兰科植物中,二叶匐茎兰表现出极高的专一性,其菌根真菌均属于Hypocrea。其余兰科植物的菌根真菌分别属于不同的科,专一性相对较低。物种丰富度和Simpson多样性指数分析结果表明,密林生境的兰科植物的菌根真菌多样性在各生长季节基本高于开阔生境。此外,两种生境的优势兰科植物的菌根真菌物种多样性随生长季节转变所呈现的变化规律是相似的:萌发期和生长期的多样性均较高,峰值出现在生长期,到果期时则大幅下降。这与高原兰科植物的生长特性及营养供求规律基本相符。     

药用植物绶草(兰科)的菌根真菌群落组成分析

兰科菌根真菌(OMF)被认为是影响兰科植物物种丰度和分布的一个重要因素.对广域分布兰科植物的菌根区系进行研究有助于人们更深入地了解兰科植物分布格局的形成机制.本研究以我国广域分布的兰科药用植物绶草Spiranthes sinensis为材料,采用Illumina Miseq高通量测序技术对北京、上海、江西、广西、云南、...     

菌根真菌与兰科植物氮营养关系的研究进展

兰科植物是典型的菌根植物。兰菌根是兰科植物根与真菌形成的菌根共生体。兰菌根真菌的营养来源影响宿主植物的生活方式和营养水平。氮是植物生长的主要限制因子。兰科植物具有富集氮的特征, 其组织和器官的氮含量通常高于同生境中的其他植物。该文综述了兰菌根真菌类别、兰科植物氮营养特征和兰菌根的氮转移机制等的研究进展, 以期为兰科植物资源的保护、再生及可持续利用的相关研究提供参考和借鉴。     

菌根真菌是唱响生物共生交响曲的主角——菌根真菌专辑序言

地球上任何生物都不是单独进行生命活动和进化的,即生物之间更多的是依靠密切联合、共生互助、需求互补和共同发展。其中,陆地生态系统中的强大分解者真菌和强大生产者植物关系密切,特别是以菌根真菌(mycorrhizal fungi)为代表的植物共生真菌自始至终与植物共生,这一强-强共生联合在维持生态平衡、保存生态系统可持续生产力与生态系统综合服务功能体系中,其分布之广、作用之多、功能之强和贡献之大,可谓名副其实的生物共生体系中的主导者。近年来,中国在真菌与植物共生研究领域成绩斐然,占据世界重要地位。本期《菌物学报》"菌根真菌专刊"刊登了2篇综述和20篇研究报告。综述分别对丛枝菌根(AM)真菌在煤矿区生态修复应用研究和兰科植物与菌根真菌的营养关系进行了总结和热点论述;研究报告分别对菌物界球囊菌门AM真菌全球公认种的中文学名给予了全面规范正确的描述、对中国部分林区红桦外生菌根真菌多样性、华山松印度块菌菌根中的块菌交配型基因、AM真菌对枳吸收磷和分泌磷酸酶的影响、转Bt基因棉叶片腐熟物抑制AM真菌定殖及菌根对磷的吸收、低pH影响AM真菌丛枝发育和磷的吸收、接种AM真菌与间作对红壤上玉米和大豆种间氮素竞争的影响、AM真菌及其菌种组合对植物根结线虫病害的影响以及接种AM真菌和施加铁可协同降低水稻砷累积等方面进行了研究。本期内容基本体现了中国菌根真菌分类、物种多样性、生理学、生态学、生理生态效应与作用机制研究的最新进展,对当前和今后开展植物共生真菌的研究具有重要的引领作用。     

云南兰科植物新资料

报道了云南兰科植物13个新记录种：宽叶红门兰、触须阔蕊兰、毛葶玉凤兰、朱兰、长唇羊耳蒜、广西鸢尾兰、长叶山兰、黄兰、聚石斛、狭唇卷瓣兰、花蜘蛛兰、大尖囊兰、槽舌兰。     

菌根及其在荒漠化土地恢复中的应用

对菌根的作用及其荒漠化对其影响,以及菌根在荒漠化土地恢复中的应用进行了探讨,指出菌根不仅能够促进植物个体养分的吸收,提高植物光合作用,增强植物抗旱、抗盐性,而且能够调节群落内植物间的关系、群落的演替轨道及其生物多样性、耕作、灌溉、过度放牧和开矿等诱发土地荒漠化过程的人类活动直接影响菌根的建立和生存,采用外来菌引入及原来残存菌培育,在恢复区建立丛状菌根植物,菌木化菌根造林及开矿土地管理中表土的存贮等方式都会有力地促进恢复地菌根的建立,并可缩短恢复周期。     

Specificity and localised distribution of mycorrhizal fungi in the soil may contribute to co-existence of orchid species

Co-occurring orchid species tend to occupy different areas and associate with different mycorrhizal fungi, suggesting that orchid mycorrhizal (OrM) fungi may be unevenly distributed within the soil and, therefore, impact the aboveground spatial distribution of orchids. To test this hypothesis, we investigated spatial variations in the community of potential OrM associates within the roots of three co-habitating orchid species (Anacamptis morio, Gymnadenia conopsea, and Orchis mascula) and the surrounding soil in an orchid-rich calcareous grassland in Southern Belgium using 454 amplicon pyrosequencing. Putative OrM fungi were broadly distributed in the soil, although variations in community composition were strongly related to the proximal host plant. The diversity and frequency of sequences corresponding to OrM fungi in the soil declined with increasing distance from orchid plants, suggesting that the clustered distribution of orchid species may to some extent be explained by the localised distribution of species-specific mycorrhizal associates.     

Mycorrhizae from Denali National Park and Preserve,Alaska

 Roots of 40 taxa of higher plants (Pteridophyta, Spermatophyta) from two alpine study sites in Denali National Park and Preserve in central Alaska were examined for their mycorrhizal colonization. We observed ectomycorrhizae on six species: Betula nana, Salix reticulata, Salix polaris, Salix arctica, Polygonum viviparum, and Dryas octopetala. Seven taxa, Cassiope tetragona, Empetrum nigrum, Ledum palustre subsp. decumbens, Ledum palustre subsp. groenlandicum, Loiseleuria procumbens, Vaccinium uliginosum and Vaccinium vitis–idaea (all Ericales), had ericoid mycorrhizae. One species, Arctostaphylos alpina, formed a typical arbutoid mycorrhiza. Two species (Sibbaldia procumbens and Aconitum delphinifolium) showed well-developed VA mycorrhizae, whereas three species of plants (Lycopodium clavatum, Silene acaulis and Oxytropis scammaniana) had vesicles, but no arbuscules. The roots of 11 other plants (Lycopodium clavatum, Lycopodium selago, Silene acaulis, Gentiana algida, Lupinus arcticus, Oxytropis scammaniana, Pedicularis langsdorffii, Pedicularis capitata, Pedicularis verticillata, Artemisia sp. and Carex bigelowii) had a variety of intracellular colonizations which are referred to as dark septate fungi. No mycorrhizae were found on 12 other plants: Equisetum arvense, Equisetum variegatum, Lycopodium alpinum, Polygonum bistorta, Saxifraga hieracifolia, Saxifraga hirculus, Astragalus alpinus, Pedicularis kanei, Petasites frigidus, Carex podocarpa, Carex microchaeta and Poa arctica. A possible ecological role of dark septate fungi is discussed. Accepted: 4 August 1995     

Mycorrhizae and their potential use in the agricultural and forestry industries

Mycorrhizal fungi associated with plant roots increase the absorption of nutrients, particularly phosphorus, and thus enhance the growth of crop plants and trees. Vesicular-arbuscular mycorrhizae (VAM) occur in approximately 90% of all vascular plants including most of the important agricultural species, whereas ectomycorrhizae are found in most of the economically important tree species of the temperate regions of the world, and in some tropical trees. These symbiotic associations are, therefore, important in crop and biomass production. For this reason they are receiving considerable attention in agriculture and forestry. Currently, VAM are utilized in fumigated soils, greenhouse crops, and in the reclamation of disturbed sites. Ectomycorrhizae are employed in the establishment of trees in nurseries, in reforestation programs, and in the production of containerized seedlings. Production of VAM and ectomycorrhiza inoculum for large scale projects is now feasible but many basic questions related to persistence of these fungi in field situations, competition with other microorganisms, and particularly the most efficient fungi to use for particular hosts remain largely unanswered.     

Symbiotic seed germination of Habenaria macroceratitis (Orchidaceae), a rare Florida terrestrial orchid

The rapid loss of native orchid habitat throughout ecologically important areas (e.g., Florida) has prompted researchers to develop appropriate plans for the propagation and reintroduction of many native orchid species. Ideally, symbiotic orchid seed germination methods are utilized in the production of orchid seedlings to be used in plant reintroduction programs. In the current study we (1) describe an efficient symbiotic seed germination protocol to germinate seeds of the rare sub-tropical terrestrial orchid Habenaria macroceratitis; (2) discuss the in vitro fungal specificity demonstrated by this species; and (3) describe the effects of three photoperiods (0/24 h, 16/8 h, 24/0 h L/D) on in vitro symbiotic seed germination of H. macroceratitis. Six fungal mycobionts were isolated from both vegetative and flowering plants of H. macroceratitis from two geographically distinct sites. Symbiotic seed germination percent was highest (65.7%) and protocorm development was most advanced (Stage 2) when seeds were cultured with fungal mycobiont Hmac-310. Seeds of H. macroceratitis demonstrated a degree of specificity toward fungal mycobionts isolated from plants originating from the same site where seed was collected. Continual darkness (0/24 h L/D) inhibited initial seed germination (Stage 1; 17.1%), but stimulated subsequent protocorm development (Stage 2; 53.5%). These findings will aid in developing an efficient symbiotic seed germination protocol for the conservation of this rare Florida terrestrial orchid, and may prove useful in the conservation of other sub-tropical terrestrial orchid species.     

蝴蝶兰属植物杂交育种研究进展

对蝴蝶兰属(Phalaenopsis)植物的种质资源, 杂交育种过程中亲本的选择和某些观赏性状的遗传规律、杂交组合登录情况等进行了综述,并且对我国杂交育种中存在的问题进行了探讨,最后结合蝴蝶兰属植物遗传育种现状,就如何加快我国蝴蝶兰属植物杂交育种和新品种培育的进程提出了建议。     

4种野生兰花种子特征及离体培养初报

对4种野生兰花--虾脊兰、羊耳蒜、石仙桃及密花石斛的果荚、种子、种胚性状进行初步研究,并对其种子进行离体培养。结果显示,4种野生兰种子为白色、淡绿或黄褐,呈纺锤体或椭球体。羊耳蒜、石仙桃及密花石斛种子具种孔,种胚浓密且清晰可见;种子萌发较快且萌发率高,其中以石仙桃及密花石斛种子萌发最快,仅需36d,萌发率高达100%。虾脊兰种子未见种孔,种胚不甚明显,种子萌发缓慢且萌发率低。4种兰科植物种子均以原球茎方式萌发,通过继代培养,获得了一批无菌苗。     

Paxillus involutus/Pinus sylvestris Mycorrhizae from Heavily Polluted Forest II. Ultrastructural and Cytochemical Observations

Paxillus involutus/Pinus sylvestris mycorrhizae, collected from experimental plots (situated in a Pino-Quercetum forest) treated with cadmium dust, were previously reported to accumulate metals like Cd, P, S, N, Al and Si in vacuolar bodies. The Gomori-Swift test was applied to the same material to reveal if cysteine-rich proteins might be involved in element detoxification. Vacuolar deposits of high and low phosphate level were both stained. Higher intensity of the Swift reaction was found in the fungal mycelium from mycorrhizae sampled from polluted plots than in mycorrhizae from unpolluted sites. In both cases a higher intensity of the test was revealed in the host cytoplasm close to the Hartig net than in internal parts of roots. Different intensities of the Gomori-Swift reaction were also observed when the Hartig net was compared to the fungal mantle. A PATAg test was additionally processed and revealed an accumulation of glycogen in rosettes and net-like structures when samples from cadmium dust treated plots were observed.     

Earthworm invasions of ecosystems devoid of earthworms: effects on soil microbes

Recent studies document North American earthworm invasions and their profound effects on the structure of the soil profile, which is the habitat for soil microorganisms (mainly fungi and bacteria). Dramatic alterations made to these layers during earthworm invasion significantly change microbial community structure and therefore microbial activities such as C transformations. Understanding the impacts of earthworm invasion on the microbes themselves will give insight into earthworm effects on microbial activities. Bacterial and actinomycete communities in earthworm guts and casts have not been studied in environments recently invaded by earthworms. Earthworm invasion tended to decrease fungal species density and fungal species diversity and richness. The presence of earthworms decreased zygomycete species abundance probably due to disruption of fungal hyphae. Physical disruption of hyphae may also explain decreased mycorrhizal colonization rates, decreased mycorrhizal abundance and altered mycorrhizal morphology in the presence of earthworms. Mixing of organic layers into mineral soil during earthworm invasion tended to decrease microbial biomass in forest floor materials while increasing it in mineral soil. In newly invaded forest soils, microbial respiration and the metabolic quotient tended to decline. In forests where either the microbial community has had time to adapt to earthworm activities, or where the destruction of the forest floor is complete, as in invasions by the Asian Amynthas hawayanus, the presence of earthworms tends to increase the metabolic quotient indicating a shift to a smaller, more active microbial community.