Articles de revues : « Mycorrhizas Morphology »

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Farias-Larios, J., S. Guzman-Gonzalez et A. Michel-Rosales. « The Advances in the Study on Mycorrhizas of Fruit Trees in Dry Tropics of Mexico ». HortScience 31, n^o 4 (août 1996) : 684c—684. http://dx.doi.org/10.21273/hortsci.31.4.684c.

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The productivity of marginal soils frequently found in the arid tropics might be improved by using VAM fungi as “biofertilizer” and as a tool of sustainable agricultural systems. Study of mycorrhizas of fruit trees was performed in 1987 in western Mexico. More progress has been made in resources, taxonomy, anatomy and morphology, physiology, ecology, effects, and application of mycorrhizas in fruit trees and ornamental plants production. Currently, five genera has been identified and inoculated plants showed significant difference in respect to plants not inoculated with mycorrhizal fungi. Citrus trees were highly dependent on mycorrhizae for normal growth and development, while the banana plants showed lower levels of root colonization by different strains of VAM fungi. The added endomycorrhizal inoculum significantly increased root fungal colonization in fruit trees and reduce the time in nursery. The current status and research trends in the study of fruit tree mycorrhizas in western Mexico are introduced, and the application prospects in sustainable agriculture also are discussed.

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TIAN, Li, Yan LI et Qiang-Sheng WU. « Exogenous Carbon Magnifies Mycorrhizal Effects on Growth Behaviour and Sucrose Metabolism in Trifoliate Orange ». Notulae Botanicae Horti Agrobotanici Cluj-Napoca 46, n^o 2 (24 janvier 2018) : 365–70. http://dx.doi.org/10.15835/nbha46210987.

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Arbuscular mycorrhizas (AMs) need the carbohydrates from host plants for its growth, whereas it is not clear whether exogenous carbon affects mycorrhizal roles. A two-chambered rootbox was divided into root + hyphae chamber and hyphae chamber (free of roots) by 37-μm nylon mesh, in which trifoliate orange (Poncirus trifoliata) seedlings and Funneliformis mosseae were applied into root + hyphae chamber, and exogenous 40 mmol/L fructose, glucose and sucrose was applied to hyphae chamber. Application of exogenous sugars dramatically elevated root mycorrhizal colonization. Sole arbuscular mycorrhizal fungi (AMF) inoculation significantly promoted plant growth and root morphology than non-AMF treatment. Mycorrhiza-improved plant growth and root modification could be enlarged by exogenous carbon, especially fructose. Exogenous carbon markedly increased root fructose, glucose and sucrose accumulation in mycorrhizal plants, especially sucrose. Exogenous fructose significantly reduced leaf and root sucrose synthase (SS) activity in synthesis direction and increased them in cleavage direction in AMF seedlings. Exogenous glucose and sucrose heavily elevated root SS activity of mycorrhizal seedlings in synthesis and cleavage direction and reduced leaf SS activity in synthesis direction. Leaf acid invertase (AI) and neutral invertase (NI) activities of mycorrhizal seedlings were decreased by exogenous carbon, except sucrose in NI. Exogenous fructose significantly increased root AI and NI activity in mycorrhizal plants. These results implied that mycorrhizal inoculation represented positive effects on plant growth, root morphology, and sucrose metabolism of trifoliate orange, which could be magnified further by exogenous carbon, especially fructose.

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Marks, G. C. « Causal morphology and evolution of mycorrhizas ». Agriculture, Ecosystems & ; Environment 35, n^o 2-3 (avril 1991) : 89–104. http://dx.doi.org/10.1016/0167-8809(91)90046-z.

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Huang, Guang-Ming, Ying-Ning Zou, Qiang-Sheng Wu, Yong-Jie Xu et Kamil Kuča. « Mycorrhizal roles in plant growth, gas exchange, root morphology, and nutrient uptake of walnuts ». Plant, Soil and Environment 66, No. 6 (23 juin 2020) : 295–302. http://dx.doi.org/10.17221/240/2020-pse.

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Walnut, an important oil fruit tree, is dependent on arbuscular mycorrhizas, while mycorrhizal roles and efficient mycorrhizal fungus in walnuts are unknown. This study was conducted to evaluate the effect of five arbuscular mycorrhizal fungi (AMF) species, including Acaulospora scrobiculata, Diversispora spurca, Glomus etunicatum, G. mosseae, and G. versiforme on plant growth, leaf gas exchange, root morphology, and root nutrient contents of walnut (Juglans regia L. Liaohe 1) seedlings. Three months of AMF inoculations later, root mycorrhizal colonisation achieved 47.0% to 76.4%. AMF treatments increased plant growth performance, dependent on AMF species. AMF-inoculated plants with D. spurca, G. etunicatum, and G. mosseae showed higher root length, projected area, surface area, and volume than non-AMF plants. Except for G. versiforme, the other four AMF treatments almost significantly increased leaf photosynthesis rate, transpiration rate, and stomatal conductivity, while reduced intercellular CO<sub>2</sub> concentrations and leaf temperature. AMF affected root nutrient contents, dependent on AMF and mineral nutrient species. These results, thereby, concluded that AMF had a positive role in walnuts, dependent on AMF species, and D. spurca was the best mycorrhizal fungus for walnut. Such results provide the potential possibility of a developing consortium of AMF in walnut cultivation management.

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Runjin, Liu, Xu Kun et Liu Pengqi. « The Advances in the Study on Mycorrhizas of Fruit Trees in China ». HortScience 30, n^o 4 (juillet 1995) : 886C—886. http://dx.doi.org/10.21273/hortsci.30.4.886c.

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The study of mycorrhizas of fruit trees was carried out in the 1980s in China. More progress has been made in resources, taxonomy, anatomy and morphology, physiology, ecology, effects, and application of mycorrhizas in fruit trees. The present status and research trends in the study of fruit tree mycorrhizas in China were introduced, and the application prospects of mycorrhizas in fruit tree cultivation also were discussed.

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Zangaro, Waldemar, Fabio Rodrigo Nishidate, Flavia Regina Spago Camargo, Graziela Gorete Romagnoli et Julia Vandressen. « Relationships among arbuscular mycorrhizas, root morphology and seedling growth of tropical native woody species in southern Brazil ». Journal of Tropical Ecology 21, n^o 5 (25 juillet 2005) : 529–40. http://dx.doi.org/10.1017/s0266467405002555.

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The relationships between arbuscular mycorrhizal fungi and root morphological characteristics were studied under greenhouse conditions of 78 tropical native woody species and 47 seedling species collected in the field. Seedlings of native woody pioneer and early secondary species that generally exhibited fine roots with a dense cover of long root hairs showed higher mycorrhizal response and root mycorrhizal colonization than late-secondary and climax species with coarse roots with a sparse cover of short root hairs. Root-hair length and incidence decreased with the progression among the successional groups while fine-root diameter increased, both in the greenhouse and in the field. The mycorrhizal response was highly correlated to root mycorrhizal colonization in the greenhouse and in the field. These parameters were inversely correlated with the seed mass and fine-root diameter, but directly correlated with root-hair incidence, both in the greenhouse and in the field. Mycorrhizal response and root mycorrhizal colonization were also directly correlated with the root-hair length and root/shoot ratio of uninoculated plants. The seedling mycorrhizal status of the early successional woody species suggests that the root traits of these fast-growing species can be more receptive to attraction, infection and colonization by arbuscular mycorrhizas than root traits of late-successional species.

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McLachlan, Jonathan W., Adeline Becquer, Rebecca E. Haling, Richard J. Simpson, Richard J. Flavel et Chris N. Guppy. « Intrinsic root morphology determines the phosphorus acquisition efficiency of five annual pasture legumes irrespective of mycorrhizal colonisation ». Functional Plant Biology 48, n^o 2 (2021) : 156. http://dx.doi.org/10.1071/fp20007.

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Mycorrhizal fungi are ubiquitous in agroecosystems and form symbiotic associations that contribute to the phosphorus (P) acquisition of many plants. The impact of mycorrhizas is most pronounced in P-deficient soil and commonly involves modifications to the root morphology of colonised plants. However, the consequences of mycorrhizal colonisation on root acclimation responses to P stress are not well described. Five annual pasture legumes, with differing root morphologies, were grown to determine the effect of mycorrhizal colonisation on shoot yield, root morphology and P uptake. Micro-swards of each legume were established in pots filled with a topsoil layer that had been amended with five rates of P fertiliser. The topsoil overlaid a low-P subsoil that mimicked the stratification of P that occurs under pasture. Mycorrhizal colonisation improved P acquisition and shoot yield in the low-P soil treatments, but did not reduce the critical external P requirement of the legumes for near-maximum yield. The yield responses of the mycorrhizal plants were associated with reduced dry matter allocation to topsoil roots, which meant that the P acquisition benefit associated with mycorrhizal colonisation was not additive in the P-deficient soil. The contribution of the mycorrhizal association to P acquisition was consistent among the legumes when they were compared at an equivalent level of plant P stress, and was most pronounced below a P stress index of ~0.5. The intrinsic root morphology of the legumes determined their differences in P-acquisition efficiency irrespective of mycorrhizal colonisation.

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Cavagnaro, T. R., L.-L. Gao, F. A. Smith et S. E. Smith. « Morphology of arbuscular mycorrhizas is influenced by fungal identity ». New Phytologist 151, n^o 2 (août 2001) : 469–75. http://dx.doi.org/10.1046/j.0028-646x.2001.00191.x.

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KUMLA, JATURONG, NAKARIN SUWANNARACH, SANTHITI VADTHANARAT et SAISAMORN LUMYONG. « Gyrodon suthepensis (Boletales, Basidiomycota), a new ectomycorrhizal fungus from northern Thailand and its ecomycorhizal association ». Phytotaxa 321, n^o 2 (15 septembre 2017) : 181. http://dx.doi.org/10.11646/phytotaxa.321.2.3.

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A new ectomycorrhizal fungus, Gyrodon suthepensis, is described based on collections from northern Thailand. It can be distinguished from the previously described Gyrodon species by the morphological characteristics. The molecular phylogenetic analyses of the internal transcribed spacers (ITS) and large subunit (LSU) of the nuclear ribosomal DNA confirms the position of the new species within the family Paxillaceae. The full description, color photographs, illustrations and the phylogenetic tree to show the position of G. suthepensis are provided. The new species grows in association with the ectomycorrhizal tree Betula alnoides, and the morphology and anatomy of mycorrhizas are described. Moreover, the identification of mycorrhizal association of G. suthepensis was confirmed by molecular methods.

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Ya-Dong, Shao, Zhang De-Jian, Hu Xian-Chun, Wu Qiang-Sheng, Jiang Chang-Jun, Xia Ting-Jun, Gao Xiu-Bing et Kuča Kamil. « Mycorrhiza-induced changes in root growth and nutrient absorption of tea plants ». Plant, Soil and Environment 64, No. 6 (31 mai 2018) : 283–89. http://dx.doi.org/10.17221/126/2018-pse.

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Tea plants grown in acidic soils are strongly dependent on arbuscular mycorrhizas, whereas it is not clear whether soil arbuscular mycorrhizal fungi (AMF) improve plant growth, root development, and nutrient absorption in tea plants. A potted study was conducted to determine the effects of Claroideoglomus etunicatum, Diversispora spurca, D. versiformis and a mixture of the three AMF species on plant growth, root morphology, root-hair growth, and leaf nutrient status in Camellia sinensis cv. Fuding Dabaicha in Jingzhou, China. After 12 weeks of AMF inoculation, root mycorrhizal colonization ranged from 15.12% to 40.23%. AMF inoculation heavily increased plant height, shoot and root biomass, and total leaf area, whilst the increased effect was ranked as C. etunicatum > D. spurca > mixed-AMF > D. versiformis in the decreasing order. Mycorrhizal inoculation also considerably increased total root length and volume, whereas obviously inhibited root-hair length and number, in company with an increment in root-hair diameter. Leaf N, P, K, Ca, Mg, Zn, and Mn contents were significantly higher in AMF-inoculated plants than in non-AMF-inoculated plants, regardless of AMF species. It concludes that AMF inoculation had positive effects on plant growth performance, root morphology, and leaf nutrient levels in cv. Fuding Dabaicha seedlings, whilst C. etunicatum performed the best effects.

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McGee, P. A. « Growth response to and morphology of mycorrhizas of Thysanotus (Anthericaceae Monocotyledonae) ». New Phytologist 109, n^o 4 (août 1988) : 459–63. http://dx.doi.org/10.1111/j.1469-8137.1988.tb03721.x.

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Lu, Li-Hui, et Qiang-Sheng Wu. « Mycorrhizas Promote Plant Growth, Root Morphology and Chlorophyll Production in White Clover ». Biotechnology(Faisalabad) 16, n^o 1 (15 décembre 2016) : 34–39. http://dx.doi.org/10.3923/biotech.2017.34.39.

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Waring, Bonnie G., Maria G. Gei, Lisa Rosenthal et Jennifer S. Powers. « Plant–microbe interactions along a gradient of soil fertility in tropical dry forest ». Journal of Tropical Ecology 32, n^o 4 (13 juin 2016) : 314–23. http://dx.doi.org/10.1017/s0266467416000286.

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Abstract:Theoretical models predict that plant interactions with free-living soil microbes, pathogens and fungal symbionts are regulated by nutrient availability. Working along a steep natural gradient of soil fertility in a Costa Rican tropical dry forest, we examined how soil nutrients affect plant–microbe interactions using two complementary approaches. First, we measured mycorrhizal colonization of roots and soil P availability in 18 permanent plots spanning the soil fertility gradient. We measured root production, root colonization by mycorrhizal fungi, phosphatase activity and Bray P in each of 144 soil cores. Next, in a full-factorial manipulation of soil type and microbial community origin, tree seedlings of Albizia guachapele and Swietenia macrophylla were grown in sterilized high-, intermediate- and low-fertility soils paired with microbial inoculum from each soil type. Seedling growth, biomass allocation and root colonization by mycorrhizas were quantified after 2 mo. In the field, root colonization by mycorrhizal fungi was unrelated to soil phosphorus across a five-fold gradient of P availability. In the shadehouse, inoculation with soil microbes had either neutral or positive effects on plant growth, suggesting that positive effects of mycorrhizal symbionts outweighed negative effects of soil pathogens. The presence of soil microbes had a greater effect on plant biomass than variation in soil nutrient concentrations (although both effects were modest), and plant responses to mycorrhizal inoculation were not dependent on soil nutrients. Taken together, our results emphasize that soil microbial communities can influence plant growth and morphology independently of soil fertility.

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BRUNDRETT, MARK, et BRYCE KENDRICK. « The roots and mycorrhizas of herbaceous woodland plants. I. Quantitative aspects of morphology ». New Phytologist 114, n^o 3 (mars 1990) : 457–68. http://dx.doi.org/10.1111/j.1469-8137.1990.tb00414.x.

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BRUNDRETT, MARK, et BRYCE KENDRICK. « The roots and mycorrhizas of herbaceous woodland plants. II. Structural aspects of morphology ». New Phytologist 114, n^o 3 (mars 1990) : 469–79. http://dx.doi.org/10.1111/j.1469-8137.1990.tb00415.x.

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Kariman, Khalil, Susan Jane Barker et Mark Tibbett. « Structural plasticity in root-fungal symbioses : diverse interactions lead to improved plant fitness ». PeerJ 6 (4 décembre 2018) : e6030. http://dx.doi.org/10.7717/peerj.6030.

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Root-fungal symbioses such as mycorrhizas and endophytes are key components of terrestrial ecosystems. Diverse in trophy habits (obligate, facultative or hemi-biotrophs) and symbiotic relations (from mutualism to parasitism), these associations also show great variability in their root colonization and nutritional strategies. Specialized interface structures such as arbuscules and Hartig nets are formed by certain associations while others are restricted to non-specialized intercellular or intracellular hyphae in roots. In either case, there are documented examples of active nutrient exchange, reinforcing the fact that specialized structures used to define specific mycorrhizal associations are not essential for reciprocal exchange of nutrients and plant growth promotion. In feremycorrhiza (with Austroboletus occidentalis and eucalypts), the fungal partner markedly enhances plant growth and nutrient acquisition without colonizing roots, emphasizing that a conventional focus on structural form of associations may have resulted in important functional components of rhizospheres being overlooked. In support of this viewpoint, mycobiome studies using the state-of-the-art DNA sequencing technologies have unearthed much more complexity in root-fungal relationships than those discovered using the traditional morphology-based approaches. In this review, we explore the existing literature and most recent findings surrounding structure, functioning, and ecology of root-fungal symbiosis, which highlight the fact that plant fitness can be altered by taxonomically/ecologically diverse fungal symbionts regardless of root colonization and interface specialization. Furthermore, transition from saprotrophy to biotrophy seems to be a common event that occurs in diverse fungal lineages (consisting of root endophytes, soil saprotrophs, wood decayers etc.), and which may be accompanied by development of specialized interface structures and/or mycorrhiza-like effects on plant growth and nutrition.

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SANDERS, I. R., et A. H. FITTER. « The ecology and functioning of vesicular-arbuscular mycorrhizas in co-existing grassland species. I. Seasonal patterns of mycorrhizal occurrence and morphology. » New Phytologist 120, n^o 4 (avril 1992) : 517–24. http://dx.doi.org/10.1111/j.1469-8137.1992.tb01801.x.

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Citernesi, A. S., C. Vitagliano et M. Giovannetti. « Plant growth and root system morphology ofOlea europaeaL. rooted cuttings as influenced by arbuscular mycorrhizas ». Journal of Horticultural Science and Biotechnology 73, n^o 5 (janvier 1998) : 647–54. http://dx.doi.org/10.1080/14620316.1998.11511028.

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Miller, R. M., B. A. D. Hetrick et G. W. T. Wilson. « Mycorrhizal fungi affect root stele tissue in grasses ». Canadian Journal of Botany 75, n^o 10 (1 octobre 1997) : 1778–84. http://dx.doi.org/10.1139/b97-892.

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Although arbuscular mycorrhizal symbiosis was initially believed to have little or no impact on root morphology, we now recognize that subtle changes do occur and that these changes may be of considerable consequence to host growth and nutrition, as well as functional growth strategy. In examining the stele and root diameters of C3 and C4 grasses, C4 grasses were demonstrated to have a significantly larger proportion of their fibrous roots occupied by stele tissue than do C3 grasses. In fact, functional growth strategy (C3 versus C4) was observed to be a relatively good predictor of stele area. Mycorrhizal fungi also influenced the amount of stele tissue, but the effect was not the same for both C3 and C4 grasses. The stele area of all C4 grasses except for Sorghastrum nutans was greater in the presence of mycorrhizal colonization. Among the C3 grasses, only Bromus inermis showed a significant increase, although Elymus cinereus and Lolium perenne displayed significant decreases in response to arbuscular mycorrhizal colonization. Changes in the stele area of the plant species were closely related to their responsiveness to mycorrhizal symbiosis and might in part explain both beneficial and detrimental responses of plants to mycorrhizae. An increase in stele circumference induced by mycorrhizae would allow for greater uptake and passage of water and nutrients to the vascular cylinder, and growth depressions could be a direct outcome of reduced stele circumference. Thus, differences in stele circumference represent a possible mechanism for mycorrhizal impacts on host plants. These findings indicate that structural differences among grasses are related to different functional capabilities and further emphasize the need for better integration of comparative anatomy and morphology procedures in the study of mycorrhizal symbiosis. Key words: stele, root anatomy, mycorrhizal dependency, functional growth strategy, mycorrhiza, C3 and C4 grasses.

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Stanojkovic, Jelena, Jasmina Glamoclija et Dusica Janosevic. « Morpho-anatomical characterization of Tuber macrosporum/Corylus avellana mycorrhizas from cultivated seedlings : Case report ». Zbornik Matice srpske za prirodne nauke, n^o 133 (2017) : 241–49. http://dx.doi.org/10.2298/zmspn1733241s.

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This study investigated the presence of mycorrhizae on seedlings from part of ten-year-old truffles plantation (about 3,000 m2) located in Eastern Serbia. This study is observation of the presence of ectomycorrhizal fungus from genus Tuber during its symbiotic stage on the roots of Corylus avellana L. Ten root samples were collected (randomly) and observed macroscopically and microscopically analyzed. There were changes in morphology and anatomy of the infected roots of C. avellana. Mantle was clearly observed to cover the roots and the mycelia formed the Harting net. Among arbitrary selected seedlings, there were found mature fruiting bodies on the surface of the soil. The truffles, identified as Tuber macrosporum Vittad, were found in the immediate vicinity of the hazelnut trees. There has been no previous information of mycorrhizae Tuber macrosporum/Corylus avellana on artificially created truffles plantation in Serbia.

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Kubota, M., T. P. McGonigle et M. Hyakumachi. « Clethra barbinervis, a member of the order Ericales, forms arbuscular mycorrhizae ». Canadian Journal of Botany 79, n^o 3 (1 mars 2001) : 300–306. http://dx.doi.org/10.1139/b01-008.

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The mycorrhizal status of Clethra barbinervis, in the family Clethraceae of the order Ericales, was investigated. Mycorrhizal colonization of C. barbinervis roots collected from naturally occurring trees in two forests in Japan was determined monthly for 12 months. In addition, mycorrhizal colonization of C. barbinervis seedlings grown in pots of field-collected soil was evaluated. Field-collected C. barbinervis roots were extensively colonized by arbuscular mycorrhizal fungi that exhibited the Paris-type morphology. At both sites, total colonization ranged from 4287% of root length and arbuscular colonization ranged from 631% of root length during the year. At one site, hyphal-coil colonization was between 3761% year round; at the other site, it increased from between 3056% during August-November to as high as 80% in January. Year round at both sites, vesicular colonization was 7% of root length or less. The Paris-type morphology was also seen in pot-grown C. barbinervis seedlings. Total colonization of pot-grown C. barbinervis seedlings was 3456% of the root length over 520 weeks. To our knowledge, this study is the first report of the mycorrhizal status of a plant in the Clethraceae and the first report of arbuscular mycorrhizae in any member of the Ericales.Key words: Paris-type, Japan, seasonal pattern, arbuscular mycorrhiza, Ericales.

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Cline, E., B. Vinyard et R. Edmonds. « Spatial effects of retention trees on mycorrhizas and biomass of Douglas-fir seedlings ». Canadian Journal of Forest Research 37, n^o 2 (février 2007) : 430–38. http://dx.doi.org/10.1139/x06-229.

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Retention forestry places seedlings in proximity to residual trees, exposing seedlings to additional sources of ectomycorrhizal fungus (EMF) inoculum. To investigate this, Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) seedlings were planted near (2–6 m) and far (16–30 m) from 44- to 72-year-old residual Douglas-fir trees in western Washington, USA. From 1998 through 2000, seedling shoot and root biomass was assessed and EMF taxa were identified using morphology and sequence analysis of internal transcribed spacer and large subunit ribosomal RNA genes. Seedlings near residual trees had significantly greater ectomycorrhiza (ECM) abundance (percent active ECM root tips), less necrotic root tips, and higher root to shoot biomass ratios. Seedlings near trees had a richness index of 4.1 EMF taxa per seedling and 42 total taxa compared with 3.5 taxa per seedling and 33 total taxa for seedlings far from trees. Proximity to residual trees may increase seedling ECM abundance and diversity.

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Shao, Ya-Dong, Xian-Chun Hu, Qiang-Sheng Wu, Tian-Yuan Yang, A. K. Srivastava, De-Jian Zhang, Xiu-Bing Gao et Kamil Kuča. « Mycorrhizas promote P acquisition of tea plants through changes in root morphology and P transporter gene expression ». South African Journal of Botany 137 (mars 2021) : 455–62. http://dx.doi.org/10.1016/j.sajb.2020.11.028.

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Currah, R. S., A. Tsuneda et S. Murakami. « Morphology and ecology of Phialocephala fortinii in roots of Rhododendron brachycarpum ». Canadian Journal of Botany 71, n^o 12 (1 décembre 1993) : 1639–44. http://dx.doi.org/10.1139/b93-199.

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The morphology of the interaction of three strains of Phialocephala fortinii with the roots of Rhododendron brachycarpum was examined by light, scanning, and transmission electron microscopy using material grown in axenic Petri dish cultures and in nonsterile pot cultures. In Petri dish cultures, Phialocephala fortinii quickly overwhelmed root tips of young seedlings, causing distortion of cells of the root apex and inhibition of elongation. In older roots, mature, vacuolated, and moribund epidermal cells were penetrated. In pot-cultured plants the epidermis was heavily colonized by hyphae growing parallel to the long axis of the root. Microsclerotia formed within individual cells, between the epidermal and the subepidermal layers, and within cells surrounding the point of emergence of lateral roots. Hyphae did not invade the stele. The effects of two strains of Phialocephala fortinii on shoot dry weight accumulation of R. brachycarpum grown in pot culture were examined and compared with the effects of Hymenoscyphus ericae, Myxotrichum stipitatum, Oidiodendron echinulatum, and Pseudogymnoascus roseus. One strain of Phialocephala fortinii had a significant negative effect on dry weight accumulation, whereas a second had no effect. Hymenoscyphus ericae had a positive effect. The remaining fungi had no effect. One strain of Phialocephala fortinii gave rise to what appeared to be sterile discocarps on the surface of soil in 4-month-old pots of R. brachycarpum. Key words: Phialocephala fortinii, Hymenoscyphus ericae, microsclerotia, Rhododendron brachycarpum, ericoid mycorrhizas, Mycelium radicis atrovirens.

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Philip, Leanne J., Usher Posluszny et John N. Klironomos. « The influence of mycorrhizal colonization on the vegetative growth and sexual reproductive potential of Lythrum salicaria L. » Canadian Journal of Botany 79, n^o 4 (1 avril 2001) : 381–88. http://dx.doi.org/10.1139/b01-010.

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Lythrum salicaria L., purple loosestrife, is a heterostylous, perennial plant with prolific and at times invasive vegetative growth and sexual reproduction. Sexual reproduction occurs following pollination and fertilization between two different floral morphs. We investigated the influence of the arbuscular mycorrhizal fungus, Glomus aggregatum Schenck and Smith emend. Koske, on the vegetative growth and sexual reproductive potential of L. salicaria. Mycorrhiza decreased plant biomass both aboveground and belowground. Flower production, number of days to anthesis, numbers of flowers per inflorescence, and inflorescence lengths were not significantly different between mycorrhizal and non-mycorrhizal treatments. However, pollen production per anther and per flower increased with mycorrhizal colonization. Though ovule production was not affected, some aspects of purple loosestrife morphology did change. Plants with mycorrhizae produced inflorescence (in lateral positions) further up the stem. In addition, flower distribution within an inflorescence differed according to morph (short, mid, and long style) such that in the mid and long morphs flower number increased with inflorescence length and was unevenly distributed, while in the short morph this distribution appeared even. The relative biomass of stems, leaves, lateral branches, and reproductive structures were not significantly different in mycorrhizal plants, whereas in the absence of mycorrhizal colonization, stem biomass was higher relative to other structures. This study suggests some vegetative and reproductive characteristics in purple loosestrife change with an association with arbuscular mycorrhizal fungi.Key words: purple loosestrife, arbuscular mycorrhizal fungi, plant reproduction.

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Massicotte, H. B., R. L. Peterson et L. H. Melville. « Ontogeny of Alnus rubra – Alpova diplophloeus ectomycorrhizae. I. Light microscopy and scanning electron microscopy ». Canadian Journal of Botany 67, n^o 1 (1 janvier 1989) : 191–200. http://dx.doi.org/10.1139/b89-027.

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Ectomycorrhizae synthesized between Alpova diplophloeus and Alnus rubra are of two morphological types: one with a mantle formed along the entire length of the lateral roots and the other, the clavate type, with the mantle confined to the apical portion of the laterals. The morphology of the mycorrhiza is dependent on the stage of lateral root elongation at the time of colonization by fungal hyphae. Clavate mycorrhizae form on lateral roots that have already elongated at the time of fungal colonization. Fungal hyphae interact with root hairs at the base of clavate mycorrhizae. Mantles of both types are fairly compact with few extramatrical hyphae. Hartig net hyphae, which branch profusely primarily in the radial direction, are confined to the epidermis and midway along the radial walls of the outer layer of cortical cells. Second-order lateral root primordia are initiated in the mature Hartig net zone. Cells in the outer layer of the cortex of mycorrhizal roots collapse during fixation, indicating the possible presence of a barrier in the cell wall blocking the ingress of fixative.

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Massicotte, H. B., L. H. Melville et R. L. Peterson. « Structural characteristics of rootfungal interactions for five ericaceous species in eastern Canada ». Canadian Journal of Botany 83, n^o 8 (1 août 2005) : 1057–64. http://dx.doi.org/10.1139/b05-046.

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A combination of light microscopy (including differential interference contrast) and laser scanning confocal microscopy was used to document the colonization patterns of epidermal cells and details of intracellular hyphal complexes of five native ericaceous hosts: Vaccinium oxycoccos L. (bog cranberry), Ledum groenlandicum Oeder. (Labrador tea), Vaccinium myrtilloides L. (velvet-leaf blueberry), Kalmia angustifolia L. (sheep laurel), and Gaultheria procumbens L. (wintergreen). Colonization patterns, hyphal complex morphology, and the structure of thick-walled epidermal cells varied considerably among hosts. Multiple hyphal connections were observed between adjacent epidermal cells, indicating that one fungal entry point may result in the colonization of more than one epidermal cell. Further field observations combined with fungal isolations from field-collected plants, identification, and reinoculation studies of other species in the large Ericaceae family are required to determine the full range of structural details in ericoid mycorrhizas.Key words: ericoid mycorrhizas, hair roots, intracellular hyphal complexes, confocal microscopy.

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Cooke, Margaret A., Paul Widden et Ivan O'Halloran. « Development of vesicular–arbuscular mycorrhizae in sugar maple (Acer saccharum) and effects of base-cation ammendment on vesicle and arbuscule formation ». Canadian Journal of Botany 71, n^o 11 (1 novembre 1993) : 1421–26. http://dx.doi.org/10.1139/b93-171.

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The development, condition, and incidence of vesicular–arbuscular mycorrhizae of Acer saccharum (sugar maple) seedlings grown in the greenhouse in natural sugar maple forest soil substrate were examined. The effects of the addition of a cation mixture containing calcium, magnesium, and potassium were also studied. The mycorrhizal structures observed were similar to those found in natural field conditions. Mycorrhizae developed intracellularly via hyphal coils, and arbuscules usually developed from these coils, forming arbusculate coils. This development is different from that observed in most annual crop plants. Vesicular–arbuscular mycorrhizal structures appeared within 30 days. The rate of mycorrhizal infection decreased, along with plant health, as the quantity of the added cations was increased, but the amendment did not affect the morphology of the infection. More vesicles were observed in the lowest level of application than in controls, suggesting a stress response and possible relationship between plant health and condition of the mycorrhizal association. Key words: Acer saccharum, development, vesicular–arbuscular mycorrhizae.

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Malik, Rondy J., et James D. Bever. « Enriched CO2 and Root-Associated Fungi (Mycorrhizae) Yield Inverse Effects on Plant Mass and Root Morphology in Six Asclepias Species ». Plants 10, n^o 11 (16 novembre 2021) : 2474. http://dx.doi.org/10.3390/plants10112474.

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While milkweeds (Asclepias spp.) are important for sustaining biodiversity in marginal ecosystems, CO2 flux may afflict Asclepias species and cause detriment to native communities. Negative CO2-induced effects may be mitigated through mycorrhizal associations. In this study, we sought to determine how mycorrhizae interacts with CO2 to influence Asclepias biomass and root morphology. A broad range of Asclepias species (n = 6) were chosen for this study, including four tap-root species (A. sullivantii, A. syriaca, A. tuberosa, and A. viridis) and two fibrous root species (A. incarnata and A. verticillata). Collectively, the six Asclepias species were manipulated under a 2 × 2 full-factorial design that featured two mycorrhizal levels (−/+ mycorrhizae) and two CO2 levels (ambient and enriched (i.e., 3.5× ambient)). After a duration of 10 months, Asclepias responses were assessed as whole dry weight (i.e., biomass) and relative transportive root. Relative transportive root is the percent difference in the diameter of highest order root (transportive root) versus that of first-order absorptive roots. Results revealed an asymmetrical response, as mycorrhizae increased Asclepias biomass by ~12-fold, while enriched CO2 decreased biomass by about 25%. CO2 did not impact relative transportive roots, but mycorrhizae increased root organ’s response by more than 20%. Interactions with CO2 and mycorrhizae were observed for both biomass and root morphology (i.e., relative transportive root). A gene associated with CO2 fixation (rbcL) revealed that the two fibrous root species formed a phylogenetic clade that was distant from the four tap-root species. The effect of mycorrhizae was most profound in tap-root systems, as mycorrhizae modified the highest order root into tuber-like structures. A strong positive correlation was observed with biomass and relative transportive root. This study elucidates the interplay with roots, mycorrhizae, and CO2, while providing a potential pathway for mycorrhizae to ameliorate CO2 induced effects.

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Rupp, L. A., K. W. Mudge et F. B. Negm. « Involvement of ethylene in ectomycorrhiza formation and dichotomous branching of roots of mugo pine seedlings ». Canadian Journal of Botany 67, n^o 2 (1 février 1989) : 477–82. http://dx.doi.org/10.1139/b89-067.

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The role of ethylene in mycorrhiza formation and root development on axenically grown seedlings of Pinus mugo Turra var. mugo was examined. Mycorrhizal formation by Laccaria laccata and Pisolithus tinctorius in a defined liquid medium was associated with increased ethylene production. Ethephon (100 μM) stimulated dichotomous branching of roots inoculated with P. tinctorius, but had no effect on those inoculated with L. laccata, or on uninoculated roots. Ethephon had no effect on the percentage of susceptible roots that became mycorrhizal with either fungus. The inhibitor of ethylene action, silver thiosulfate, had no significant effect on mycorrhiza formation by P. tinctorius, but it did show a trend toward decreased mycorrhiza formation by L. laccata when applied at concentrations of 10 μM or higher. Silver thiosulfate at 100 or 500 μM slightly increased dichotomous root branching of seedlings inoculated with either fungus, but these concentrations also caused blackening of root meristems and inhibition of root growth. These results are consistent with the interpretation that endogenous ethylene may influence mycorrhiza formation and associated changes in root morphology.

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Fidelibus, Matthew W., Chris A. Martin et Jean C. Stutz. « Arbuscular Mycorrhizal (AM) Fungal Isolates Differentially Altered Morphology of Young `Volkamer' Lemon Plants under Well-watered Conditions ». HortScience 32, n^o 3 (juin 1997) : 443F—444. http://dx.doi.org/10.21273/hortsci.32.3.443f.

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Four AM fungal isolates (Glomus sp.) were screened for effects on growth of `Volkamer' lemon (Citrus volkameriana Ten. and Pasq.) under well-watered conditions. Plants were inoculated with an isolate of AM fungi, or non-inoculated. Non-mycorrhizal plants received more phosphorus (P) fertilizer than mycorrhizal plants because mycorrhizae enhance P uptake. Mycorrhizal and non-mycorrhizal plants were grown in 8-liter containers for 3 months in a glasshouse. Plants were then harvested, and root length colonized by mycorrhizal fungi, leaf P concentration, and plant growth were determined. Root length colonized by AM fungi differed among isolates; control plants were non-mycorrhizal. Leaf P concentration was in the optimal range for all plants; however, plants colonized by Glomus mosseae Isolate 51C had higher leaf P concentration than non-mycorrhizal plants. Plants colonized by Glomus AZ112 had higher leaf P concentration than all other plants. All plants had similar canopy leaf area, shoot length, and shoot dry mass. Plants colonized with AM fungi, except Glomus mosseae Isolate 51C, had longer root length and greater root dry mass than non-mycorrhizal plants. All mycorrhizal plants had lower shoot:root dry mass and leaf area:root length ratios than non-mycorrhizal plants. Our results showed that under optimal P nutrition and well-watered conditions, AM fungal isolates differentially altered the morphology of citrus plants by stimulating root growth.

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LIANG, Sheng-Min, Dao-Ju JIANG, Miao-Miao XIE, Ying-Ning ZOU, Qiang-Sheng WU et Kamil KUČA. « Physiological responses of mycorrhizal symbiosis to drought stress in white clover ». Notulae Botanicae Horti Agrobotanici Cluj-Napoca 49, n^o 1 (24 mars 2021) : 12209. http://dx.doi.org/10.15835/nbha49112209.

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The aim of the present study was to analyze the effects of two arbuscular mycorrhizal fungi (AMF), Funneliformis mosseae and Paraglomus occultum, on leaf water status, root morphology, root sugar accumulation, root abscisic acid (ABA) levels, root malondialdehyde (MDA) content, and root antioxidant enzyme activities in white clover (Trifolium repens L.) exposed to well-watered (WW) and drought stress (DS) conditions. The results showed that root colonization by F. mosseae and P. occultum was significantly decreased by 7-week soil drought treatment. Under drought stress conditions, mycorrhizal fungal treatment considerably stimulated root total length, surface area and volume, as compared with non-mycorrhizal controls. In addition, inoculation with arbuscular mycorrhizal fungi also increased leaf relative water content and accelerated the accumulation of root glucose and fructose under drought stress. Mycorrhizal plants under drought stress registered higher activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) and ABA levels in roots, while lower MDA contents, relative to non-mycorrhizal plants. As a result, mycorrhiza-inoculated plants represented better physiological activities (e.g. antioxidant defense systems, root morphology, and sugar accumulation) than non-inoculated plants in response to soil drought, whilst P. occultum had superior effects than F. mosseae.

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Tisserant, B., S. Gianinazzi et V. Gianinazzi-Pearson. « Relationships between lateral root order, arbuscular mycorrhiza development, and the physiological state of the symbiotic fungus in Platanus acerifolia ». Canadian Journal of Botany 74, n^o 12 (1 décembre 1996) : 1947–55. http://dx.doi.org/10.1139/b96-233.

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The rapid development of an efficient root system resulting from arbuscular mycorrhiza formation is essential to the successful establishment of many plant species. We have analysed root system development and used histochemical staining to define relationships between lateral root order dynamics, arbuscular mycorrhiza development, and the physiological state of the symbiotic fungus Glomus fasciculatum (Thaxter sensu Gerdeman) Gerd & Trappe amend. Walker and Koske, in a woody plant species Platanus acerifolia Willd. Arbuscular mycorrhiza induced modifications in root system development in P. acerifolia, compared with nonmycorrhizal root systems. Third-order lateral roots dominated in arbuscular mycorrhizal plants, while second-order laterals were most numerous in nonmycorrhizal systems. Arbuscular mycorrhiza colonization was closely related to the appearance of different root orders; the most active mycelium (characterized by fungal succinate dehydrogenase and alkaline phosphatase activities) was mainly localized in newly formed lateral roots. Nine weeks after inoculation with G. fasciculatum the proportion of alkaline phosphatase-active mycelium strongly decreased in all root orders, and this was related to an increased phosphorus content of the host plant. The dynamics of development of the arbuscular mycorrhizal fungus and the possible regulation of its activity by the host plant are discussed. Keywords: arbuscular mycorrhiza, fungal enzyme, root system morphology, Platanus acerifolia, Glomus fasciculatum.

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Tominaga, Takaya, Chihiro Miura, Naoya Takeda, Yuri Kanno, Yoshihiro Takemura, Mitsunori Seo, Masahide Yamato et Hironori Kaminaka. « Gibberellin Promotes Fungal Entry and Colonization during Paris-Type Arbuscular Mycorrhizal Symbiosis in Eustoma grandiflorum ». Plant and Cell Physiology 61, n^o 3 (2 décembre 2019) : 565–75. http://dx.doi.org/10.1093/pcp/pcz222.

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Abstract Arbuscular mycorrhizas (AMs) are divided into two types according to morphology: Arum- and Paris-type AMs. Gibberellins (GAs) mainly inhibit the establishment of Arum-type AM symbiosis in most model plants, whereas the effects of GAs on Paris-type AM symbiosis are unclear. To provide insight into the mechanism underlying this type of symbiosis, the roles of GAs were investigated in Eustoma grandiflorum when used as the host plant for Paris-type AM establishment. Eustoma grandiflorum seedlings were inoculated with the model AM fungus, Rhizophagus irregularis, and the effects of GA and the GA biosynthesis inhibitor uniconazole-P on the symbiosis were quantitatively evaluated. Exogenous GA significantly increased hyphopodium formation at the epidermis, thus leading to the promotion of fungal colonization and arbuscule formation in the root cortex. By contrast, the suppression of GA biosynthesis and signaling attenuated fungal entry to E. grandiflorum roots. Moreover, the exudates from GA-treated roots strongly induced the hyphal branching of R. irregularis. Our results show that GA has an contrasting effect on Paris-type AM symbiosis in E. grandiflorum compared with Arum-type AM symbiosis. This finding could be explained by the differential regulation of the early colonization stage, where fungal hyphae make contact with and penetrate the epidermis.

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BAREA, J. M., R. M. TOBAR et C. AZCON-AGUILAR. « Effect of a genetically modified Rhizobium meliloti inoculant on the development of arbuscular mycorrhizas, root morphology, nutrient uptake and biomass accumulation in Medicago sativa ». New Phytologist 134, n^o 2 (octobre 1996) : 361–69. http://dx.doi.org/10.1111/j.1469-8137.1996.tb04641.x.

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Chen, Weile, Roger T. Koide, Thomas S. Adams, Jared L. DeForest, Lei Cheng et David M. Eissenstat. « Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees ». Proceedings of the National Academy of Sciences 113, n^o 31 (18 juillet 2016) : 8741–46. http://dx.doi.org/10.1073/pnas.1601006113.

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Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich “hotspots” can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together.

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Hetrick, B. A. D., G. W. T. Wilson et T. C. Todd. « Relationships of mycorrhizal symbiosis, rooting strategy, and phenology among tallgrass prairie forbs ». Canadian Journal of Botany 70, n^o 8 (1 août 1992) : 1521–28. http://dx.doi.org/10.1139/b92-191.

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The response of 23 tallgrass prairie forbs to mycorrhizal symbiosis and P fertilization was assessed in steamed and non-sterile prairie soil. For each plant species, root diameters, root fibrousness, root to shoot ratio, plant dry weight, mycorrhizal root colonization, mycorrhizal dependence, P dependence, and phenology were measured. Using these data, cluster analysis, stepwise discriminant analysis, and canonical discriminant analysis of the data revealed that the forbs could be divided into three distinct groups based on mycorrhizal dependence, root morphology, and phenology in descending order of importance. Cluster groups 1 and 2 contained obligately and facultatively mycotrophic forbs, respectively, while the third group did not benefit from the symbiosis. Models for prediction of mycorrhizal dependence, constructed using stepwise regression analysis, were based largely on root fibrousness. A regression analysis comparing mycorrhizal dependence and root fibrousness was conducted, and group means and 95% confidence ellipses were examined for each group. These revealed that the mycorrhizal dependence and root fibrousness of groups 1 and 3 are relatively constant regardless of P level, while the response of forbs of group 2 is more plastic, i.e., mycorrhizal dependence decreases and root fibrousness increases as P level increases. The relationship between plant response to mycorrhizal symbiosis and life strategy or growth pattern is discussed. Key words: mycorrhizal dependency, vesicular–arbuscular mycorrhizae, root systems.

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Widden, Paul. « The morphology of vesicular – arbuscular mycorrhizae in Clintonia borealis and Medeola virginiana ». Canadian Journal of Botany 74, n^o 5 (1 mai 1996) : 679–85. http://dx.doi.org/10.1139/b96-086.

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During a survey of the vesicular–arbuscular mycorrhizal (VAM) associations of forest herbs in a deciduous forest in the southern Laurentian mountains in Quebec, two liliaceous species, Clintonia borealis and Medeola virginiana, revealed very distinctive morphology. In both species, once the epidermis was penetrated, the fungus spread towards the centre of the root via intracellular hyphae until the innermost layer of the cortex was reached, at which point the fungus spread laterally and tangentially through the cortical cells adjacent to the endodermis via a series of banana-shaped projections (bobbits). These eventually differentiated into the arbuscules and the VAM might spread from this inner cortical layer back into the outer cortical layers. In C. borealis, the hyphae coiled in the cortex, and vesicles were formed in the upper cortical cells. In M. virginiana, no coiling took place, but extensive diverticulae were produced by the intracellular hyphae in the cortical cells, close to their point of exit, and vesicles were produced in the inner cortex as swellings from the bobbits. These two mycorrhizae have some similarities to one in Colchicum autumnale described by I. Gallaud (1905. Rev. Gen. Bot. 17). Keywords: vesicular–arbuscular mycorrhizae, Clintonia borealis, Medeola virginiana, Liliaceae, morphology.

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Akatsuki, Maiko, et Naoki Makita. « Influence of fine root traits on in situ exudation rates in four conifers from different mycorrhizal associations ». Tree Physiology 40, n^o 8 (25 avril 2020) : 1071–79. http://dx.doi.org/10.1093/treephys/tpaa051.

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Abstract Plant roots can exude organic compounds into the soil that are useful for plant survival because they can degrade microorganisms around the roots and enhance allelopathy against other plant invasions. We developed a method to collect carbon (C) exudation on a small scale from tree fine roots by C-free filter traps. We quantified total C through root exudation in four conifers from different microbial symbiotic groups (ectomycorrhiza (ECM) and arbuscular mycorrhiza (AM)) in a cool-temperate forest in Japan. We determined the relationship of mass-based exudation rate from three diameter classes (<0.5, 0.5–1.0, and 1.0–2.5 mm) of the intact root system with root traits such as morphological traits including root diameter, specific root length (SRL), specific root area (SRA), root tissue density (RTD) and chemical traits including root nitrogen (N) content and C/N. Across species, the mass-based root exudation rate was found to correlate with diameter, SRA, RTD, N and C/N. When comparing mycorrhizal types, there were significant relationships between the exudation and diameter, SRL, SRA, root N and C/N in ECM species; however, these were not significant in AM species. Our results show that relationships between in situ root exudation and every measured trait of morphology and chemistry were strongly driven by ECM roots and not by AM roots. These differences might explain the fact that ECM roots in this study potentially covaried by optimizing the exudation and root morphology in forest trees, while exudation in AM roots did not change with changes in root morphology. In addition, the contrasting results may be attributable to the effect of degree and position of ECM and AM colonization in fine root system. Differences in fine root exudation relationships to root morphology for the two types of mycorrhizae will help us better understand the underlying mechanisms of belowground C allocation in forest ecosystems.

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Vierheilig, Horst. « Regulatory mechanisms during the plant arbuscular mycorrhizal fungus interaction ». Canadian Journal of Botany 82, n^o 8 (1 août 2004) : 1166–76. http://dx.doi.org/10.1139/b04-015.

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Abundant data are available on some aspects of the arbuscular mycorrhizal symbiosis, for example, plant nutrition, but because of difficulties immanent to arbuscular mycorrhizal fungi, such as the inability to culture them axenically, the relatively long time it takes to achieve root colonization, and the simultaneous presence of different morphologic stages of the fungus in the root, less information is accumulated on other aspects such as the regulation of mycorrhization. Regulatory processes in the plant arbuscular mycorrhizal fungus interaction start before root colonization by the fungus and even before a direct physical contact between the host and the fungal symbiont. Some of the signals exchanged are still a matter of debate and will be discussed further on. After the penetration of the root by the fungus, depending on the developmental stage of the arbuscular mycorrhizal association (e.g., early or mature), a range of plant responses is activated. The possible function of several plant responses in the regulation of mycorrhization is discussed.Key words: arbuscular mycorrhiza, Glomales, autoregulation, flavonoid, recognition, root exudates.

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Dickson, Sandy, Peter Schweiger, F. Andrew Smith, Bengt Söderström et Sally Smith. « Paired arbuscules in the Arum-type arbuscular mycorrhizal symbiosis with Linum usitatissimum ». Canadian Journal of Botany 81, n^o 5 (1 mai 2003) : 457–63. http://dx.doi.org/10.1139/b03-037.

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Experiments were conducted to investigate the "paired" arbuscules characteristic of Arum-type mycorrhizal colonization in Linum usitatissimum L. The development and senescence of arbuscular structures were followed in a time course study. Roots were freeze-sectioned longitudinally and mycorrhizal structures visualized using nitroblue tetrazolium, a vital stain to indicate metabolically active arbuscules and intercellular hyphae, followed by acid fuchsin counterstaining. Arbuscules were imaged using laser scanning confocal microscopy. The volume and surface area of each arbuscule of a developing paired structure were measured using three-dimensional imaging software. Arbuscules occurred in pairs in adjacent cortical cells arising from a single, radial intercellular hypha. These "paired" arbuscules often appeared to be at different developmental stages. Logistic regression and measurement of surface area indicated that there was a delay in initiation of the second arbuscule.Key words: Arum-type arbuscular mycorrhiza, double staining, metabolic activity, morphology, confocal microscopy, Linum usitatissimum.

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Zsögön, Agustin, Marcio Rodrigues Lambais, Vagner Augusto Benedito, Antonio Vargas de Oliveira Figueira et Lázaro Eustáquio Pereira Peres. « Reduced arbuscular mycorrhizal colonization in tomato ethylene mutants ». Scientia Agricola 65, n^o 3 (2008) : 259–67. http://dx.doi.org/10.1590/s0103-90162008000300006.

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Plant hormones are likely key regulators of arbuscular mycorrhizae (AM) development. However, their roles in AM are not well known. Here mutants in five hormone classes introgressed in a single tomato (Lycopersicon esculentum Mill. Syn Solanum lycopersicum L.) background (cv. Micro-Tom) were used to determine their effects on AM development and the expression of defense-related genes (chitinases and b-1,3-glucanases) in roots. Under low P conditions, mutant epinastic (epi) and Never ripe (Nr), ethylene overproducer and low sensitivity, respectively, had the intraradical colonization by Glomus clarum highly inhibited, as compared to the control Micro-Tom (MT). No significant alterations in fungal colonization were observed in mutants affecting other hormone classes. Under low P conditions, the steady state levels of transcripts encoding a class I basic chitinase (chi9) were higher in mycorrhizal epi and Nr mutant roots as compared to MT controls. In contrast the steady state levels of a class III acidic b-1,3-glucanase (TomPR-Q'a) transcripts in mycorrhizal epi mutant roots were significantly lower than in mycorrhizal MT roots. Root colonization in epi mutants was accompanied by several alterations in fungal morphology, as compared to root colonization in MT controls. The data suggest that ethylene may play an important role in controlling intraradical arbuscular mycorrhizal fungal growth.

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Galic, Zoran, Sasa Orlovic, Bojana Klasnja, Andrej Pilipovic et Marina Katanic. « Improvement of production of high-yield poplar varieties seedlings by mycorrhiza application ». Zbornik Matice srpske za prirodne nauke, n^o 112 (2007) : 67–74. http://dx.doi.org/10.2298/zmspn0712067g.

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Research related to the effects of treatment by mycorrhiza preparations Ectovit, Rhodovit (preparations Symbio-m Ltd., Czech Rep.) and their combination on growth of four high-yield poplar clones of Populus deltoides and one variety of Populus x euramericana are presented in this paper. In order to make more accurate assessment of mycorrhiza effect, soil characteristics such as morphology, texture and chemical composition were determined. The study results indicate that mycorrhized cuttings had the same or the better survival in all the study clones compared to the control. The application of the preparation Ectovit and Rhodovit resulted averagely in the first class planting stock of all the study clones. The combination of the preparations Ectovit and Rhodovit produced averagely the first class planting stock only of the clone Populus x euramericana.

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Hoffman, M. T., et D. T. Mitchell. « The root morphology of some legume spp. in the south-western Cape and the relationship of vesicular-arbuscular mycorrhizas with dry mass and phosphorus content of Acacia saligna seedlings ». South African Journal of Botany 52, n^o 4 (août 1986) : 316–20. http://dx.doi.org/10.1016/s0254-6299(16)31527-7.

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Mendoza, R. E., et E. A. Pagani. « Influence of phosphorus nutrition on mycorrhizal growth response and morphology of mycorrhizae inLotus tenuis ». Journal of Plant Nutrition 20, n^o 6 (juin 1997) : 625–39. http://dx.doi.org/10.1080/01904169709365282.

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Wira Yuwati, Tri, Wanda Septiana Putri et Badruzsaufari. « Comparison of Arbuscular Mycorrhizal Spores Abundance Under Sengon (Falcataria moluccana (Miq.) Barneby & ; Grimes) Planted on Deep Peat and Mineral Soils ». Journal of Tropical Peatlands 10, n^o 2 (1 décembre 2020) : 1–8. http://dx.doi.org/10.52850/jtpupr.v10i2.2062.

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Mycorrhizae are known as soil fungi because of their habitat in the rooting area (rhizosphere). Nearly 97% of terrestrial plant species interact or symbiotic with mycorrhizae. Symbiosis is formed in the form of an exchange between nutrients and carbohydrates and helps plants absorb P. elements. In Kalimantan, sengon often used as industrial material because it is fast-growing species and widely cultivated by the community. Sengon is a common species planted in mineral soils; however, due to the rising demand of sengon timber, it has been planted on peatlands. This study aims to compare the abundance of arbuscular mycorrhizal spores and identify the morphology of arbuscular mycorrhizal spores associated with Sengon planted on peatlands and mineral soils. This study used a wet sieving method and root staining from the modification of Vierherling et al. 1996 and calculation of root mycorrhizal colonization with gridline techniques. The research used the normality test of data distribution and the T test (Independent sample T test) to determine trends and comparison of differences in the abundance of FMA spores. The study results showed a significant difference in the abundance of AMF in the form of colonization by calculating the percentage of AMF colonization in the sengon root in mineral soils and peatlands of 23.56% 41.67%, respectively. The spore density on mineral soils and peatlands were 18.05 / 50gr and 1.09 / 50gr, respectively. Identification results showed that there were four genera found in peat soil locations, namely the genus Glomus, Gigaspora, Scutellospora, and Acaulospora, while in the mineral soil were found three generas namely genus Glomus, Scutellospora, and Acaulospora. Out of the four generas, the most abundant in both soil types was Glomus.

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Wubet, Tesfaye, Michael Weiß, Ingrid Kottke et Franz Oberwinkler. « Morphology and molecular diversity of arbuscular mycorrhizal fungi in wild and cultivated yew (Taxus baccata) ». Canadian Journal of Botany 81, n^o 3 (1 mars 2003) : 255–66. http://dx.doi.org/10.1139/b03-020.

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Taxus baccata L. roots collected from two sites in southern Germany were heavily colonized by arbuscular mycorrhizal fungi (AMF). The colonization pattern was of the Paris type. The diversity of the colonizing AMF species was investigated using polymerase chain reaction based molecular techniques. The internal transcribed spacer (ITS) region of the DNA from AMF within the roots was amplified using Glomeromycota-specific primers and then cloned and sequenced. Phylogenetic analysis using a data set of 5.8S rDNA sequences from a wide range of glomeralean taxa as well as data sets of partial ITS2 sequences from glomeralean subgroups indicated root colonization by four sequence types of Glomus and one sequence type of Archaeospora. These sequence types are distinct from any previously published sequences and differed between the two study sites.Key words: arbuscular mycorrhiza, Paris-type AM, molecular diversity, ribosomal internal transcribed spacers, Taxus baccata.

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Boris, Lazarević, Lošák Tomáš et Manschadi Ahmad M. « Arbuscular mycorrhizae modify winter wheat root morphology and alleviate phosphorus deficit stress ». Plant, Soil and Environment 64, No. 1 (16 janvier 2018) : 47–52. http://dx.doi.org/10.17221/678/2017-pse.

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Arbuscular mycorrhizal (AM) root colonization is known to have beneficial effects on plant growth especially under phosphorus (P) deficit conditions. The objectives of present study were: (i) to quantify changes in early wheat root development of AM-inoculated (AMI) and AM-free (AMF) roots under limited P availability; (ii) to assess possible mitigating effect of AM inoculation on photochemical efficiency under P deficit stress. AMI (inoculated with Rhizophagus irregularis) and AMF wheat plants were grown for 20 days in low (1 μmol/L) and high (50 μmol/L)P treatments. AM inoculation affected root morphology and shoot P concentration in low P treatment. AM inoculation alleviated reduction of the total root length in low P treatment, mainly due to an increase of fine roots length(< 0.5 mm). Contrastingly, shoot dry weight was reduced by AM inoculation in low P treatment. P deficiency decreased photochemical efficiency of wheat plants. However, due to increased sink capacity and facilitated nutrient concentrations AM inoculation alleviates phosphorus deficit stress and increased photochemical efficiency.

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Imhof, Stephan. « Subterranean structures and mycorrhiza of the achlorophyllous Burmannia tenella (Burmanniaceae) ». Canadian Journal of Botany 77, n^o 5 (16 octobre 1999) : 637–43. http://dx.doi.org/10.1139/b99-034.

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Plants of the myco-heterotrophic Burmannia tenella Benth. form star-shaped root systems consisting of 0.7-2 mm thick, succulent, brittle roots, reaching lengths of up to 3 cm. In cross section the roots consist of an epidermis, about 10 layers of parenchymatous cortex cells, an endodermis with U-shaped secondary cell wall depositions, and a very reduced central cylinder with two to five central xylem elements and two opposite phloem strands, surrounded by a pericycle of relatively large cells. Based on the thick, aseptate, intracellularly coiled hyphae, arbuscules, and the frequent vesicles, the fungal association of B. tenella is considered to be a Paris-type arbuscular mycorrhiza. The morphological and anatomical structures of the root are discussed in the context of the mycorrhizal dependency of B. tenella. In some root samples, a second fungus with septate hyphae colonized the cortex intracellularly. This fungus restricts the spread of the aseptate symbiont without causing morphological changes to the cortex cells.Key words: Burmanniaceae, root morphology, root anatomy, arbuscular mycorrhiza, myco-heterotrophy, neotropical.

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Sarmiento-López, Luis G., Melina López-Meyer, Gabriela Sepúlveda-Jiménez, Luis Cárdenas et Mario Rodríguez-Monroy. « Photosynthetic performance and stevioside concentration are improved by the arbuscular mycorrhizal symbiosis in Stevia rebaudiana under different phosphate concentrations ». PeerJ 8 (19 octobre 2020) : e10173. http://dx.doi.org/10.7717/peerj.10173.

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In plants, phosphorus (P) uptake occurs via arbuscular mycorrhizal (AM) symbiosis and through plant roots. The phosphate concentration is known to affect colonization by AM fungi, and the effect depends on the plant species. Stevia rebaudiana plants are valuable sources of sweetener compounds called steviol glycosides (SGs), and the principal components of SGs are stevioside and rebaudioside A. However, a detailed analysis describing the effect of the phosphate concentration on the colonization of AM fungi in the roots and the relationship of these factors to the accumulation of SGs and photochemical performance has not been performed; such an analysis was the aim of this study. The results indicated that low phosphate concentrations (20 and 200 µM KH2PO4) induced a high percentage of colonization by Rhizophagus irregularis in the roots of S. rebaudiana, while high phosphate concentrations (500 and 1,000 µM KH2PO4) reduced colonization. The morphology of the colonization structure is a typical Arum-type mycorrhiza, and a mycorrhiza-specific phosphate transporter was identified. Colonization with low phosphate concentrations improved plant growth, chlorophyll and carotenoid concentration, and photochemical performance. The transcription of the genes that encode kaurene oxidase and glucosyltransferase (UGT74G1) was upregulated in colonized plants at 200 µM KH2PO4, which was consistent with the observed patterns of stevioside accumulation. In contrast, at 200 µM KH2PO4, the transcription of UGT76G1 and the accumulation of rebaudioside A were higher in noncolonized plants than in colonized plants. These results indicate that a low phosphate concentration improves mycorrhizal colonization and modulates the stevioside and rebaudioside A concentration by regulating the transcription of the genes that encode kaurene oxidase and glucosyltransferases, which are involved in stevioside and rebaudioside A synthesis in S. rebaudiana.

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