Effects of arbuscular mycorrhizae on biomass and nutrients in the aquatic plant Littorella uniflora

1. It has been hypothesised that the symbiosis with arbuscular mycorrhizal fungi (AMF) leads to a higher uptake of phosphorus (P) and nitrogen (N) in aquatic plants, but it has never been shown experimentally without the use of fungicides. In particular, the symbiosis may be important for nutrient uptake by isoetids in oligotrophic lakes, where low concentrations of inorganic N and P both in the water and in the sediment limit the growth of plants and where symbiosis facilitates the uptake of nutrients from the sediment. 2. Plants of the isoetid Littorella uniflora were propagated under the sterile conditions without an AMF infection. The plants were then grown for 60 days with and without re‐infection by AMF, and with either high (150 μm ) or low (ambient concentration approximately 15 μm ) CO₂ concentration. 3. The study proved that the symbiosis between AMF and L. uniflora had a positive impact on the retention of N and P in the plants at very low nutrient concentrations in the water and on biomass development. Shoot biomass and standing stocks of both P and N were significantly higher in re‐infected plants. 4. Raised CO₂ concentration resulted in a fivefold increase in hyphal infection, but had no impact on the number of arbuscules and vesicles in the cross sections. There were significantly higher biomass and lower tissue P and N concentrations in the plants from high CO₂ treatments. This resulted in similar standing stocks of P and N in plants from low and high CO₂ treatments. 5. The results from this study showed that the symbiosis between AMF and L. uniflora is an important adaptation enabling isoetids to grow on nutrient‐poor sediments in oligotrophic lakes.     

Elevated alkalinity and sulfate adversely affect the aquatic macrophyte Lobelia dortmanna

The increase in alkalinity and SO₄ ^2? in softwater lakes can negatively affect pristine isoetid population because the increase in alkalinity and SO₄ ^2? can stimulate sediment mineralization and consequently cause anoxia. The consequences of increased sediment mineralization depend on the ability of isoetids such as Lobelia dortmanna to oxidize the rhizosphere via radial O₂ loss. To study how alkalinity and SO₄ ^2? affect the isoetid L. dortmanna, and if negative effects could be alleviated by neighboring plants, three densities of L. dortmanna (“Low”?=?64 plants m^?2, “Medium”?=?256 plants m^?2 and “High”?=?1,024 plants m^?2) were exposed to elevated alkalinity in the water column, or a combination of both elevated alkalinity and SO₄ ^2?, and compared to a control situation. The combination of SO₄ ^2? and alkalinity significantly increased mortality, lowered areal biomass and reduced actual photosynthetic efficiency. Plant density did not significantly alleviate the negative effects caused by SO₄ ^2? and alkalinity. However, actual photosynthetic efficiency was significantly positively correlated to redox potential in the sediment, indicating a positive relationship between plant performance and sediment oxidation. The negative effects on L. dortmanna were probably caused by long periods of tissue anoxia by itself or in combination with H₂S intrusion. Therefore, increase in both SO₄ ^2? and alkalinity surface water can dramatically affect L. dortmanna populations, causing reduction or even disappearance of this icon species.     

蒙古沙冬青及其伴生植物AM真菌物种多样性

于2015年7月在内蒙古乌海、磴口2个样地选取蒙古沙冬青(Ammopiptanthus mongolicus)及其伴生植物为研究对象,分别采集0-20 cm和20-40 cm土层根围土样,利用高通量测序方法分析了不同植物AM真菌群落结构和物种多样性,发掘新物种,为补充和完善AM真菌分类体系提供依据。试验共分离鉴定3纲5目6科9属89个AM真菌OTU,属包括Glomus,Funneliformis,Diversispora,Claroideoglomus,Rhizophagus,Septoglomus,Scutellospora,Ambispora和Paraglomus。与形态学研究结果相比,高通量鉴定结果在属水平上更丰富。同一土层不同样地,蒙古沙冬青AM真菌丰度和多样性指数高于伴生植物;同一土层不同植物,AM真菌丰度和多样性指数表现为磴口高于乌海;同一植物不同样地,AM真菌ACE指数和Chao1指数20-40 cm土层高于0-20 cm土层,Simpson指数和Shannon指数0-20 cm土层高于20-40 cm土层。RDA分析表明,AM真菌ACE指数和Chao1指数与土壤碱解N显著正相关,与酸性磷酸酶显著负相关;Simpson指数和Shannon指数与碱性磷酸酶显著正相关,与pH显著负相关。结果表明,蒙古沙冬青AM真菌物种多样性高于伴生植物,同一样地,寄主植物与土壤深度共同作用对AM真菌群落组成有显著影响。     

丛枝菌根真菌物种多样性研究进展

丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)在不同生态系统均发挥至关重要的作用,研究其多样性能够为AMF物种资源的保护和利用提供科学依据。AMF不能被离体纯培养以及自身的高变异性等因素严重阻碍了对其进行深入研究,随着研究方法的不断改进,尤其是新一代测序技术的运用,极大加速了人们对AMF物种多样性的认识。本文主要从AMF分类系统、不同宿主植物和不同生境中的AMF物种多样性及AMF物种多样性研究方法(包括形态鉴定、Sanger测序和高通量测序)方面介绍AMF物种多样性研究进展,并且探讨AMF物种多样性研究中存在的主要问题,认为在今后AMF物种多样性研究中不仅要注重运用新的研究手段,还应该着重解决AMF不能离体纯培养的问题。     

Global sampling of plant roots expands the described molecular diversity of arbuscular mycorrhizal fungi

We aimed to enhance understanding of the molecular diversity of arbuscular mycorrhizal fungi (AMF) by building a new global dataset targeting previously unstudied geographical areas. In total, we sampled 96 plant species from 25 sites that encompassed all continents except Antarctica. AMF in plant roots were detected by sequencing the nuclear SSU rRNA gene fragment using either cloning followed by Sanger sequencing or 454-sequencing. A total of 204 AMF phylogroups (virtual taxa, VT) were recorded, increasing the described number of Glomeromycota VT from 308 to 341 globally. Novel VT were detected from 21 sites; three novel but nevertheless widespread VT (Glomus spp. MO-G52, MO-G53, MO-G57) were recorded from six continents. The largest increases in regional VT number were recorded in previously little-studied Oceania and in the boreal and polar climatic zones — this study providing the first molecular data from the latter. Ordination revealed differences in AM fungal communities between different continents and climatic zones, suggesting that both biogeographic history and environmental conditions underlie the global variation of those communities. Our results show that a considerable proportion of Glomeromycota diversity has been recorded in many regions, though further large increases in richness can be expected in remaining unstudied areas.     

丛枝菌根真菌物种多样性研究进展

丛枝菌根(arbuscular mycorrhiza, AM)真菌是生态系统中生物多样性的重要组分之一,具有十分丰富的物种多样性、遗传多样性和功能多样性.该真菌分类地位不断提高已上升至门,下设1个纲、4个目、13个科,19个属,现已报道214种.丛枝菌根对保持生态平衡、稳定和提高生态系统可持续生产力具有重要作用.本文分析了世界范围内丛枝菌根真菌物种多样性研究现状、不同生态系统中影响丛枝菌根真菌物种多样性的关键因子及其调控途径;认为分子生物学技术是今后丛枝菌根真菌物种多样性研究的主要方法.     

Dispersal of arbuscular mycorrhizal fungi and plants during succession

Arbuscular mycorrhizal (AM) fungi are important root symbionts that enhance plant nutrient uptake and tolerance to pathogens and drought. While the role of plant dispersal in shaping successional vegetation is well studied, there is very little information about the dispersal abilities of AM fungi. We conducted a trap-box experiment in a recently abandoned quarry at 10 different distances from the quarry edge (i.e. the potential propagule source) over eleven months to assess the short term, within-year, arrival of plant and AM fungal assemblages and hence their dispersal abilities. Using DNA based techniques we identified AM fungal taxa and analyzed their phylogenetic diversity. Plant diversity was determined by transporting trap soil to a greenhouse and identifying emerging seedlings. We recorded 30 AM fungal taxa. These contained a high proportion of ruderal AM fungi (30% of taxa, 79% of sequences) but the richness and abundance of AM fungi were not related to the distance from the presumed propagule source. The number of sequences of AM fungi decreased over time. Twenty seven plant species (30% of them ruderal) were recorded from the soil seed traps. Plant diversity decreased with distance from the propagule source and increased over time. Our data show that AM fungi with ruderal traits can be fast colonizers of early successional habitats.     

Flooding greatly affects the diversity of arbuscular mycorrhizal fungi communities in the roots of wetland plants

The communities of arbuscular mycorrhizal fungi (AMF) colonizing the roots of three mangrove species were characterized along a tidal gradient in a mangrove swamp. A fragment, designated SSU-ITS-LSU, including part of the small subunit (SSU), the entire internal transcribed spacer (ITS) and part of the large subunit (LSU) of rDNA from samples of AMF-colonized roots was amplified, cloned and sequenced using AMF-specific primers. Similar levels of AMF diversity to those observed in terrestrial ecosystems were detected in the roots, indicating that the communities of AMF in wetland ecosystems are not necessarily low in diversity. In total, 761 Glomeromycota sequences were obtained, which grouped, according to phylogenetic analysis using the SSU-ITS-LSU fragment, into 23 phylotypes, 22 of which belonged to Glomeraceae and one to Acaulosporaceae. The results indicate that flooding plays an important role in AMF diversity, and its effects appear to depend on the degree (duration) of flooding. Both host species and tide level affected community structure of AMF, indicating the presence of habitat and host species preferences.     

喀斯特地区丛枝菌根真菌遗传多样性

为探明喀斯特地区丛枝菌根真菌( AMF)的遗传多样性特征,利用巢式PCR和DGGE相结合的分子生物学方法对茂兰喀斯特多个植被类型下的AMF遗传多样性进行了研究.结果表明,喀斯特地区AMF遗传多样性指数和物种丰富度分别平均为3.50和41,远高于非喀斯特对照样地的2.68和17,分析表明,喀斯特地区较高的AMF多样性与此地区丰富的植物多样性以及特殊的生态环境有关,是与喀斯特生态系统长期相互选择的结果.不同植被类型下的AMF多样性差异显著,相似性指数最高为0.34,喀斯特地区AMF的群落结构随着植被类型的改变发生显著变化;基因测序显示,喀斯特地区AMF的优势菌属是生态适应性很强的球囊霉属,在喀斯特石漠化生态恢复中具有较强的利用潜力.     

林火对植物根围丛枝菌根真菌多样性的影响

林火是森林生态系统的一种主要干扰因子,以青岛市三标山林火迹地为研究对象,采集荆条(Vitex negundo)、胡枝子(Lespedeza bicolor)、花木蓝(Indigofera kirilowii)、青花椒(Zanthoxylum schinifolium)和野青茅(Deyeuxia arundinacea)5种优势植物根围土壤,研究不同林火强度对丛枝菌根(AM)真菌多样性的影响。结果表明,AM真菌侵染率和孢子密度随火灾强度的加强而降低;非过火区植物根围土壤中,分离鉴定出AM真菌3属11种,轻度过火区分离鉴定出AM真菌3属10种,中度过火区分离鉴定出AM真菌3属9种,重度过火区分离鉴定出AM真菌3属8种。过火区AM真菌种丰度低于非过火区。过火区和非过火区AM真菌的重要值和优势种不同,非过火区植物根围的优势种是地球囊霉(Glomus geosporum)、台湾球囊霉(G.taiwanensis)、分支巨孢囊霉(Gigaspora ramisporophora)、极大巨孢囊霉(Gi.gigantean)、福摩萨球囊霉(G.formosanum)、悬钩子球囊霉(G.rubiforme)、柯氏无梗囊霉(Acaulospora koskei)和松蜜无梗囊霉(A.thomii);轻度过火区植物根围的优势种是地球囊霉和台湾球囊霉;中度过火区的是台湾球囊霉和地球囊霉(野青茅除外);重度过火区植物根围的优势种是地球囊霉。不同强度的过火区对AM真菌群落组成有不同程度的影响。认为林火降低植物根围土壤中AM真菌多样性。     

Seasonal variation in crassulacean acid metabolism by the aquatic isoetid Littorella uniflora

The seasonal temperature acclimation in crassulacean acid metabolism (CAM) and photosynthetic performance were investigated in the aquatic isoetid, Littorella uniflora. Plants were collected monthly from January to September, and CAM capacity and photosynthesis rates were measured at 5, 10, 15, and 20?°C. Seasonal acclimation was observed for CAM (Q (10) range: 0.6-1.8), and CAM was optimised close to ambient temperature throughout the season. Thus, in winter acclimated L. uniflora, the short-term response to raised temperature resulted in a decline in CAM capacity. Even though the ambient CAM increased from winter to spring/summer, CAM was present in cold acclimated plants, thus indicating an ecophysiological role for CAM even in winter. Similar to CAM, seasonal acclimation was observed in the light and carbon-saturated photosynthesis (Q (10) values ranged from 1.4 to 2.3), and the photosynthetic capacity was generally higher during the winter at all temperatures, indicating compensatory investments in the photosynthetic apparatus. Thus, L. uniflora displayed seasonal temperature acclimation with respect to both CAM and photosynthesis. The estimated in situ contribution of CAM to the carbon budget in L. uniflora was independent of season and varied from 23 to 46?%. A positive correlation between photosynthetic capacity and CAM capacity (both measured in the lab at temperature close to ambient temperature) was found, and the ratio of CAM activity to photosynthetic capacity was higher in summer compared with winter plants. Overall, the results from the present study support the suggested role of CAM as a carbon conserving mechanism of importance for survival in a carbon-limited habitat.     

极旱荒漠植物对AM真菌物种多样性的影响

2015年7月在甘肃安西极旱荒漠国家级自然保护区采集膜果麻黄Ephedra przewalskii、红砂Reaumuria songarica、合头草Sympegma regelii、泡泡刺Nitraria sphaerocarpa和珍珠猪毛菜Salsola passerine 5种典型荒漠植物根区土壤样品,分析了植物种类对arbuscular mycorrhiza(AM)真菌群落组成和生态分布的影响。在分离的7属45种AM真菌中包括无梗囊霉属Acaulospora 17种,球囊霉属Glomus 13种,这两属是5种植物共同优势属;盾巨孢囊霉属Scutellospora 5种,管柄囊霉属Funneliformis 4种,根内根生囊霉属Rhizophagus 3种,近明囊霉属Claroideoglomus 2种,多孢囊霉属Diversispora1种。主成分分析研究说明5种植物根区AM真菌群落组成和物种多样性差异显著。结果表明,植物种类对AM真菌群落组成和分布特征影响显著。     

Calcium opens the dialogue between plants and arbuscular mycorrhizal fungi

Calcium ion is considered a ubiquitous second messenger in all eukaryotic cells. Analysis of intracellular Ca²⁺ concentration dynamics has demonstrated its signalling role in plant cells in response to a wide array of environmental cues. The implication of Ca²⁺ in the early steps of the arbuscular mycorrhizal symbiosis has been frequently claimed, mainly by analogy with what firmly demonstrated in the rhizobium-legume symbiosis. We recently documented transient Ca²⁺ changes in plant cells challenged with diffusible molecules released by arbuscular mycorrhizal fungi. Ca²⁺ measurements by the recombinant aequorin method provided new insights into the molecular communications between plants and these beneficial fungi.Key words: legume symbioses, arbuscular mycorrhiza, calcium signalling, fungal signal, plant cell cultures, aequorinIn the rhizosphere plants meet a wide array of microorganisms. In favorable interactions, such as arbuscular mycorrhizal (AM) and nitrogen fixing symbioses, a dialogue is progressively established between the two interacting organisms to make the appropriate partner choice. These two-way communications rely on the interchange of signals released by both potential symbionts. After perception of the signalling molecules, a signal transduction pathway is induced, leading to the activation of the proper genetic and developmental program in both partners.Variations in intracellular free Ca²⁺ concentration occur as one of the initial steps in signalling pathways activated in plants when they encounter pathogens,¹ fungal biocontrol agents² and nitrogen-fixing bacteria.³ Molecules secreted by microorganisms, after binding to specific receptors, trigger in plant cells transient changes in cytosolic Ca²⁺ level, due to the influx of the ion from the extracellular environment and/or the release from internal Ca²⁺ storage compartments.^4,5 Ca²⁺ messages delivered to plant cells are at least partly deciphered on the basis of their spatial and temporal features. The occurrence of different Ca²⁺ signatures guarantees the specificity of the ensuing physiological responses.In the legume-rhizobium symbiosis a definite pattern of Ca²⁺ oscillations has been reported to occur in response to the rhizobial signalling molecule, the Nod factor, in the nucleus and perinuclear cytoplasm of the root hair.⁶ The Ca²⁺ spike number has been recently demonstrated to regulate nodulation gene expression.⁷Legumes are able to engage in a dual symbiotic interaction, with rhizobia and AM fungi. Components of the Ca²⁺-mediated signalling pathway are shared by the two symbioses.⁸ In the mycorrhizal signal transduction pathway the involvement of Ca²⁺ has long been speculated, based on the observed similarities with symbiotic nitrogen fixation.³To evaluate the possible participation of Ca²⁺ in the early steps of the AM symbiosis, we have used a simplified experimental system given by plant cell suspension cultures stably expressing the bioluminescent Ca²⁺-sensitive reporter aequorin.⁹ The use of cultured cells circumvents the problem posed by multilayered organs: in aequorin-transformed seedlings, possible Ca²⁺ changes occurring in rhizodermal cells—the first place where the AM fungal signals are perceived and transduced—can be misrecorded due to luminescence calibration over all root cell layers, resulting in an underestimation of the Ca²⁺ signal in the responsive cells. An experimental design based on challenging host plant cells with the culture medium of different AM fungi (Gigaspora margarita, Glomus mosseae and intraradices) provided the first firm evidence that Ca²⁺ is involved as intracellular messenger during mycorrhizal signalling, at least in a pre-contact stage. Cytosolic Ca²⁺ changes, characterized by specific kinetic parameters, were triggered by diffusates obtained from AM resting and germinating spores,⁹ and extraradical mycelium.¹⁰ Cultured plant cells demonstrated to be competent to perceive the diffusible signal released by AM fungi and to decode the message in a Ca²⁺-dependent pathway. Based on these experiments, it seems that AM fungi announce their presence to the plant through the constitutive release of a chemical signal, even before experiencing the proximity of the plant or its AM symbiotic signals. The notion that the secreted fungal molecules herald, through Ca²⁺, a beneficial message which can be acknowledged only by competent receivers, is supported by: (1) the lack of defense response induction and the upregulation of some genes essential for the AM symbiosis initiation in host plant cells; (2) the unresponsiveness of cultured cells from the nonhost plant Arabidopsis thaliana.Ca²⁺-mediated perception of both AM fungal and rhizobial signals by plant cells unifies the signalling pathways activated in the two symbioses. However, the actual occurrence of Ca²⁺ spiking in AM symbiosis remains to be ascertained, due to limitations of the recombinant aequorin method, when applied to an asynchronous cell population. Contribution of internal Ca²⁺ stores, in particular the nucleus, to the observed Ca²⁺ changes will be a future research goal to be achieved through a pharmacological approach and/or targeting of Ca²⁺ indicators to intracellular compartments.The identification of the plant-derived mycorrhizal signal as strigolactones¹¹ and their inducing activity on AM fungi¹² have represented a major breakthrough in the AM symbiosis research field. Elucidation of the chemical nature of the AM fungal factor, which plays several effects on host plants,^9,13–15 is eagerly awaited.Understanding how AM fungi and rhizobia select compatible plant hosts, thus activating the appropriate symbiotic program, is another facet to be considered in the future to get a complete overview of early signaling events in legume symbioses. Analysis of Ca²⁺ signalling implication in the microbial partner would require the delivery of reliable and sensitive Ca²⁺ probes (such as aequorinor GFP-based¹⁶) for Ca²⁺ measurements in living microorganisms. The recombinant aequorin method has been successfully applied to monitor dynamic changes in intracellular Ca²⁺ levels in the bacteria Anabaena sp.,¹⁷ E. coli,¹⁸ and recently by us in rhizobial strains.¹⁹ Unfortunately, AM fungi have proved not to be amenable to stable transformation, being coenocytic, multinucleate and heterokaryotic,^20,21 and only transient transformants have been obtained so far.^22,23 Further development of the transformation technologies may provide in the future a valuable tool to analyse, from the fungal side, signal perception and transduction during arbuscular mycorrhiza establishment.     

AM真菌遗传多样性研究进展

丛枝菌根（arbuscular mycorrhiza,AM）真菌是一类专性共生多核生物,至今尚未获得纯培养,与植物根系共生后才能完成其生活史。该类真菌无性繁殖,具有独特的遗传特性,属于真菌界球囊菌门（Glomeromycota）,共有200余种。研究发现AM真菌种群间以及种群内,甚至单一孢子内都存在大量基因变异,表明该类真菌具有丰富的遗传多样性。本文总结了近年来有关AM真菌遗传多样性方面的研究进展,并讨论了存在的问题。     

Identification of arbuscular mycorrhizal fungi in soils and roots of plants colonizing zinc wastes in southern Poland

 Analysis of the community of arbuscular mycorrhizal (AM) fungi in roots of Fragaria vesca growing in a heavy metal contaminated site was carried out on a Zn waste site near Chrzanow (southern Poland). The waste substratum was characterized by high contents of Pb, Zn, Cd, Cu and As, and by low levels of N, P and organic matter. Spores of Glomales were isolated by wet sieving and DNA was isolated from individual spores. Nested polymerase chain reaction (PCR) with taxon-specific primers was used to identify the species Glomus mosseae, Glomus intraradices and Glomus claroideum. Spores of other fungi were morphologically characterized and new taxon-discriminating molecular probes were developed for two of them (Glomus sp. HM-CL4 and HM-CL5) based on variations in the large ribosomal subunit (25S rDNA). High sequence similarities were found between Glomus sp. HM-CL4 and Glomus gerdemanii, and between Glomus sp. HM-CL5 and Glomus occultum. The designed primers were used to characterize the population of AM fungi colonizing the roots of F. vesca collected from the Zn waste site. The analysis, carried out on roots stained with trypan blue, showed that the most effective colonizer was closely related to G. gerdemannii. G. claroideum and the G. occultum-like fungus were slightly less common whilst frequencies of G. intraradices and G. mosseae in roots were much lower. The analysis of mycorrhiza stained with rhodizoniate to localize heavy metal accumulation showed that the stain does not influence the PCR reaction. Seventy percent of the root samples containing positively stained fungal hyphae were found to be colonized by G. mosseae. The data obtained demonstrate the usefulness of nested PCR for studies carried out in polluted areas. It will enable selection of AM fungi which are able to colonize plant roots under heavy metal stress conditions, as well as the identification of fungi showing high in situ accumulation of potentially toxic elements. Accepted: 7 July 2000     

Evolutionary maintenance of genomic diversity within arbuscular mycorrhizal fungi

Most organisms are built from a single genome. In striking contrast, arbuscular mycorrhizal fungi appear to maintain genomic variation within an individual fungal network. Arbuscular mycorrhizal fungi dwell in the soil, form mutualistic networks with plants, and bear multiple, potentially genetically diverse nuclei within a network. We explore, from a theoretical perspective, why such genetic diversity might be maintained within individuals. We consider selection acting within and between individual fungal networks. We show that genetic diversity could provide a benefit at the level of the individual, by improving growth in variable environments, and that this can stabilize genetic diversity even in the presence of nuclear conflict. Arbuscular mycorrhizal fungi complicate our understanding of organismality, but our findings offer a way of understanding such biological anomalies.     

古尔班通古特沙漠南缘短命植物根际AM真菌群落特征研究

调查了我国新疆古尔班通古特沙漠南缘雅玛里克山和黑山头典型小半灌木荒漠中分布的6种优势短命植物(ephemeral plants)小车前Plantago minuta、囊瓣顶冰花Gagea sacculifera、黑鳞顶冰花Gagea nigra、伊犁郁金香Tulipa iliensis、鸢尾蒜Ixiolirion tataricum和串珠老鹳草Geranium transversale根际土壤中AM真菌多样性、孢子密度、物种丰度、相对多度、频度、重要值等。共分离到无梗囊霉属Acaulospora和球囊霉属Glomus 23种AM真菌。6种植物根际土壤中AM真菌孢子密度无显著差异。其中球囊霉属占有绝对的优势,频度为100%,相对多度为99.8%,为优势属。聚丛球囊霉G.aggregatum、幼套球囊霉G.etunicatum、近明球囊霉G.claroideum、沙漠球囊霉G.deserticola 4种AM真菌频度、孢子密度、相对多度及重要值都显著高于其它AM真菌种类,为优势种;它们的频度均大于50%,且G.aggregatum>G.claroideum>G.etunicatum>G.deserticola;它们的孢子密度大小顺序为G.aggregatum>G.etunicatum>G.claroideum>G.deserticola,其中G.aggregatum的孢子密度、频度、相对多度和重要值最高。     

Presence of arbuscular mycorrhizal fungi in South Florida native plants

The roots of 27 species of South Florida plants in 15 families (including one cycad, six palms, one Smilax, and 19 dicotyledons) native to pine rockland and tropical hardwood hammock communities were examined for arbuscular mycorrhizal fungi (AMF). These plants grow in the biologically diverse but endangered Greater Everglades habitat. Roots from field-grown and potted plants were cleared and stained. All 27 species had AMF and include 14 species having an endangered or threatened status. The Paris-type colonization occurred in two species in the families Annonaceae and Smilacaceae. The Arum-type occurred in 22 species in the families Anacardiaceae, Arecaceae (Palmae), Boraginaceae, Cactaceae (questionable), Euphorbiaceae, Fabaceae, Lauraceae, Melastomataceae, Polygalaceae, Rubiaceae, Simaroubaceae, Ulmaceae, and Zamiaceae. Three species in the families Fabaceae, Lauraceae, and Simaroubaceae had a mix of Paris- and Arum-types. The results have implications for the restoration of these endangered plant communities in the Everglades.