Artículos de revistas: "Alder Frankia"

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Hendrickson, O. Q., W. H. Fogal y D. Burgess. "Growth and resistance to herbivory in N2-fixing alders". Canadian Journal of Botany 69, n.º 9 (1 de septiembre de 1991): 1919–26. http://dx.doi.org/10.1139/b91-241.

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Fixation of atmospheric N2 may provide an advantage to woody plants in N-limited environments, but may also alter their resistance to herbivory. Studies in adjacent plantings of three North American shrub alders (Alnus spp.) and three Eurasian tree alders showed significant species differences in susceptibility to a leaf-mining sawfly (Fenusa dohrnii) and in response to inoculation with a N2-fixing actinomycete (Frankia). During the first 5 years, woody biomass production ranged from 0.3 t∙ha−1∙year−1 in Alnus viridis ssp. sinuata (Sitka alder) to 8.3 t∙ha−1∙year−1 in Alnus incana ssp. incana (grey alder). Grey alder and another tree species (Alnus japonica) were attacked infrequently and suffered little sawfly damage except in plots with poor growth. The tree species Alnus glutinosa (black alder) was attacked frequently, and sawfly damage was greatest in plots with the best growth. The shrub species Alnus viridis ssp. crispa (green alder) was also attacked frequently but was highly resistant to larval feeding. Frequently attacked species showed greater damage in the lower portion of the crown. Frankia inoculation increased green alder biomass by 87% but had no significant effect on grey alder or black alder. The concept of a growth-defense trade-off does not fully explain the interactions between Alnus spp. and F. dohrnii. Key words: Alnus, Fenusa dohrnii, Frankia, biomass production, plant–herbivore interactions, leaf miner.

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Bélanger, Pier-Anne, Jean-Philippe Bellenger y Sébastien Roy. "Strong modulation of nutrient distribution in Alnus glutinosa as a function of the actinorhizal symbiosis". Botany 91, n.º 4 (abril de 2013): 218–24. http://dx.doi.org/10.1139/cjb-2012-0184.

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Micro- and macro-nutrient acquisition by plants and microorganisms is a cornerstone for their survival and has a direct impact on biogeochemical cycling. In this study, we investigated, in controlled conditions, how the availability of exogenous nitrate impacted nutrient acquisition and distribution in black alder (Alnus glutinosa (L.) Gaertn.) in the presence, or absence, of its nitrogen-fixing bacterial symbiont (Frankia sp.). Our findings show that alder physiology and distribution of nutrients between aerial and root tissues were strongly influenced by the presence of the symbiont. In both nodulated and non-nodulated alders, root allocation and total plant biomass were positively correlated, except when nodulated alders were subjected to low nitrate conditions (≤15 ppm). Alders receiving 45 ppm exogenous nitrate had a less developed actinorhizal symbiosis. These findings reflect the importance of root exploration in relation to plant dependence to exogenous nitrate. Nutrient composition of alder aerial tissues, in particular molybdenum, was significantly altered in the presence of Frankia. In the context of plant leaf-litter mutualism involving metals and N exchange, our findings of high Mo and P translocation to shoots of non-nodulated alders underscores how the state of the symbiosis in actinorhizal plants can influence the biogeochemical cycling of elements.

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Huss-Danell, Kerstin, Per-Olof Lundquist y Helene Ohlsson. "N2 fixation in a young Alnus incana stand, based on seasonal and diurnal variation in whole plant nitrogenase activity". Canadian Journal of Botany 70, n.º 8 (1 de agosto de 1992): 1537–44. http://dx.doi.org/10.1139/b92-193.

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N2 fixation by grey alder, Alnus incana (L.) Moench, was studied in the field during two growing seasons in northern Sweden. Alders were planted in a nitrogen-poor soil. Each alder had its root system enclosed in an open-ended cylinder that was closed with a gas-tight lid around the stem base to serve as cuvette during nitrogenase activity (acetylene reducing activity) measurements. To follow the seasonal variation, nitrogenase activity was measured at noon on 15 occasions for each alder in 1987 and on 15 occasions in 1988. Diurnal variation in nitrogenase activity was studied at six occasions, but no obvious pattern in the diurnal variation was found. Nitrogenase activity began shortly after leaf emergence at the very end of May, increased in June, stayed high although with some variation through July and August, declined during September, and was zero in early October. Cumulative nitrogenase activity over the season was converted to cumulative N2 fixation after determination of molar ratio nitrogenase activity to N2 fixation. This conversion was facilitated as the Frankia chosen as symbiont was lacking hydrogenase activity. Control experiments showed that the introduced symbiont was the only infective Frankia in the soil. N2 fixation was estimated to be 0.23 and 2.83 g N/(alder∙year) in the 1st and 2nd year, respectively. Despite its young age, A. incana was apparently capable of high N2 fixation rates at the high latitude studied. Key words: Alnus incana, hydrogenase, intact plants, N2 fixation, seasonal variation, spreading of Frankia.

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Welsh, Allana K., Jeffrey O. Dawson, Gerald J. Gottfried y Dittmar Hahn. "Diversity of Frankia Populations in Root Nodules of Geographically Isolated Arizona Alder Trees in Central Arizona (United States)". Applied and Environmental Microbiology 75, n.º 21 (4 de septiembre de 2009): 6913–18. http://dx.doi.org/10.1128/aem.01103-09.

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ABSTRACT The diversity of uncultured Frankia populations in root nodules of Alnus oblongifolia trees geographically isolated on mountaintops of central Arizona was analyzed by comparative sequence analyses of nifH gene fragments. Sequences were retrieved from Frankia populations in nodules of four trees from each of three mountaintops (n = 162) and their levels of diversity compared using spatial genetic clustering methods and single-nucleotide or 1, 3, or 5% sequence divergence thresholds. With the single-nucleotide threshold level, 45 different sequences with significant differences between the mountaintops were retrieved, with the southern site partitioning in a separate population from the two other sites. Some of these sequences were identical in nodules from different mountaintops and to those of strains isolated from around the world. A high level of diversity that resulted in the assignment of 14 clusters of sequences was also found on the 1% divergence level. Single-nucleotide and 1% divergence levels thus demonstrate microdiversity of frankiae in root nodules of A. oblongifolia trees and suggest a partitioning of diversity by site. At the 3 and 5% divergence levels, however, diversity was reduced to three clusters or one cluster, respectively, with no differentiation by mountaintop. Only at the 5% threshold level do all Frankia strains previously assigned to one genomic group cluster together.

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Russo, R. O., J. C. Gordon y G. P. Berlyn. "Evaluating Alder-Endophyte (Alnus acuminata-Frankia- Mycorrhizae) Interactions". Journal of Sustainable Forestry 1, n.º 1 (1 de enero de 1993): 93–110. http://dx.doi.org/10.1300/j091v01n01_06.

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Russo, Ricardo O. "Evaluating alder-endophyte (Alnus acuminata-Frankia-Mycorrhizae) interactions". Plant and Soil 118, n.º 1-2 (agosto de 1989): 151–55. http://dx.doi.org/10.1007/bf02232801.

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Huss-Danell, Kerstin y Helene Ohlsson. "Distribution of biomass and nitrogen among plant parts and soil nitrogen in a young Alnus incana stand". Canadian Journal of Botany 70, n.º 8 (1 de agosto de 1992): 1545–49. http://dx.doi.org/10.1139/b92-194.

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Grey alder, Alnus incana (L.) Moench, was inoculated with the local source of Frankia and planted in nitrogen-poor soil in northern (63.8°N, 20.3°E) Sweden. Each alder root system was enclosed in a cylinder that served as an open-ended cuvette for nitrogenase activity measurements. The alders grew well, especially during the 2nd year of the study. The final leaf area in each season was more closely related to total alder biomass than final height of alders. The alders lost 17% of their total dry mass as leaf litter each year. This corresponded to 33 g dry mass and 0.67 g N per alder during the 2nd year. During the 2 years the soil N increment was 0.52 g N per alder. Leaf litter N and the increase in soil N corresponded to 27 and 17%, respectively, of the N2 fixed in the 2 years. Already at a young age, N2-fixing A. incana can apparently contribute to an improved fertility of N deficient soils. Key words: aboveground biomass, Alnus incana, belowground biomass, leaf litter, nitrogen content, soil N increment.

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Batzli, Janet McCray y Jeffrey O. Dawson. "Development of flood-induced lenticels in red alder nodules prior to the restoration of nitrogenase activity". Canadian Journal of Botany 77, n.º 9 (18 de diciembre de 1999): 1373–77. http://dx.doi.org/10.1139/b99-082.

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Red alder (Alnus rubra Bong.) is a nitrogen-fixing woody plant that is common on wetland sites and tolerates flooding through a variety of induced morphological and physiological changes. Among these changes are the formation of hypertrophied nodule lenticels and the subsequent full restoration of nitrogenase activity after 50 days of flooding. The objective of this study was to examine fine structural changes within red alder nodules during lenticel development that correspond to changes in nitrogenase activity during a 50-day experimental flood. Nodulated seedlings of red alder were grown under greenhouse conditions and then exposed to root flooding for 1, 20, 35, or 50 days. At each harvest, estimates of nitrogenase activity were made via acetylene reduction, and nodule samples were taken for light-microscope examination. Only after 50 days of flooding did red alder show restoration of nitrogenase to pretreatment levels. At this time, Frankia vesicles were found to be directly adjacent to developing lenticel tissue and large intercellular spaces. Intercellular space within the nodule increased from 0.6% in nonflooded tissue to 5.7% after 50 days of flooding. Our results demonstrate the sensitivity of the nitrogenase enzyme to low oxygen soil conditions and indicate that substantial morphological change within the nodule must occur before red alder can regain the capacity to fix nitrogen under flooded conditions.Key words: Alnus rubra, Frankia, waterlogged, biological nitrogen fixation, hypertrophied lenticels, intercellular space.

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GREITNER, CAROL S. y WILLIAM E. WINNER. "Effects of O3 on alder photosynthesis and symbiosis with Frankia". New Phytologist 111, n.º 4 (abril de 1989): 647–56. http://dx.doi.org/10.1111/j.1469-8137.1989.tb02359.x.

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10

Roy, Melanie, Adrien C. Pozzi, Raphaëlle Gareil, Melissande Nagati, Sophie Manzi, Imen Nouioui, Nino Sharikadze et al. "Alder and the Golden Fleece: high diversity of Frankia and ectomycorrhizal fungi revealed from Alnus glutinosa subsp. barbata roots close to a Tertiary and glacial refugium". PeerJ 5 (18 de julio de 2017): e3479. http://dx.doi.org/10.7717/peerj.3479.

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Background Recent climatic history has strongly impacted plant populations, but little is known about its effect on microbes. Alders, which host few and specific symbionts, have high genetic diversity in glacial refugia. Here, we tested the prediction that communities of root symbionts survived in refugia with their host populations. We expected to detect endemic symbionts and a higher species richness in refugia as compared to recolonized areas. Methods We sampled ectomycorrhizal (EM) root tips and the nitrogen-fixing actinomycete Frankia communities in eight sites colonized by Alnus glutinosa subsp. barbata close to the Caucasus in Georgia. Three sites were located in the Colchis, one major Eurasian climatic refugia for Arcto-Tertiary flora and alders, and five sites were located in the recolonized zone. Endemic symbionts and plant ITS variants were detected by comparing sequences to published data from Europe and another Tertiary refugium, the Hyrcanian forest. Species richness and community structure were compared between sites from refugia and recolonized areas for each symbionts. Results For both symbionts, most MOTUs present in Georgia had been found previously elsewhere in Europe. Three endemic Frankia strains were detected in the Colchis vs two in the recolonized zone, and the five endemic EM fungi were detected only in the recolonized zone. Frankia species richness was higher in the Colchis while the contrary was observed for EM fungi. Moreover, the genetic diversity of one alder specialist Alnicola xanthophylla was particularly high in the recolonized zone. The EM communities occurring in the Colchis and the Hyrcanian forests shared closely related endemic species. Discussion The Colchis did not have the highest alpha diversity and more endemic species, suggesting that our hypothesis based on alder biogeography may not apply to alder’s symbionts. Our study in the Caucasus brings new clues to understand symbioses biogeography and their survival in Tertiary and ice-age refugia, and reveals that isolated host populations could be of interest for symbiont diversity conservation.

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Batzli, Janet McCray, Jeff F. Zimpfer, Valérie Huguet, Charles A. Smyth, Maria Fernandez y Jeffrey O. Dawson. "Distribution and abundance of infective, soilborne Frankia and host symbionts Shepherdia, Alnus, and Myrica in a sand dune ecosystem". Canadian Journal of Botany 82, n.º 5 (1 de mayo de 2004): 700–709. http://dx.doi.org/10.1139/b04-044.

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We describe presence, abundance, and distribution of three sympatric nitrogen-fixing shrubs and their symbiotic diazatroph, Frankia, in a sand dune ecosystem differing in successional stage, vegetative cover, edaphic characteristics, and topography. Distribution of actinorhizal Myrica gale L., Alnus incana (L.) Moench subsp. rugosa (Du Roi) Clausen, and Shepherdia canadensis (L.) Nutt. was analyzed among 120 sampling locations representing a gradient of successional stages in a sand dune system along Lake Michigan. In a greenhouse study, seedlings of these species were employed to bioassay the presence and abundance of infective Frankia in soils. Shepherdia-infective Frankia was detected in 80% of the plots, while Alnus- and Myrica-infective Frankia were found in 65% and 64% of the plots, respectively, with no Frankia found in 18% of the plots. Only 14% of the plots supported actinorhizal host-plant species. Infective Frankia were present in soils of young dunes prior to the establishment of any actinorhizal hosts. Shepherdia-infective Frankia were more abundant in soils from drier, earlier successional sites, while Alnus- and Myrica-infective Frankia were more abundant in moister soils of later successional communities. A previous study had revealed that nodular Frankia strains at this site were host specific for Shepherdia and largely so for Myrica and Alnus, which had only a small proportion of shared strains (Huguet et al. 2001). The likelihood of host-plant nodulation by soilborne Frankia was increased by the presence of actinorhizal plants in general, but not by the presence of their respective specific host plants. Submerged soils had no infectious capacity, whereas soils with greater in situ moisture content and soils subject to intermittent saturation tended to have lower infectious capacities overall. Our results suggest that soilborne, infective Frankia genotypes are not only host specific, but are also associated with spatially and chronologically distinct sets of ecological conditions.Key words: speckled alder, sweet gale, Canada buffalo berry, actinorhizal, nitrogen fixation, Frankia, root nodules.

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Domenach, A. M. y F. Kurdali. "Influence des réserves azotées sur la formation des feuilles d’Alnus glutinosa et ses conséquences dans l'estimation de la fixation d'azote". Canadian Journal of Botany 67, n.º 3 (1 de marzo de 1989): 865–71. http://dx.doi.org/10.1139/b89-116.

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The influence of nitrogen reserves on leaf formation of 5- to 6-year-old plants of Alnus glutinosa (L.) Gaertn. was investigated using a 15N labelling method. Nitrogen reserves were derived essentially from the root system and along with N fixation by Frankia, supported the growth of the young leaves. The reserves represent 10% of the total nitrogen in the leaves at the end of the growing period under natural or environmentally controlled conditions. The percentage of fixed nitrogen in alder leaves was estimated to be 87% taking into account the nitrogen reserves and using the isotopic comparison with a nonfixing plant (Populus alba L.). Several conditions requiring the use of 15N methods to estimate the symbiotic nitrogen fixation by Frankia were formulated. The selection of samples for analysis must be from the most recently formed leaves at the end of the growing season to avoid the influence of nitrogenous reserves. Key words: nitrogen reserves, Alnus glutinosa, Populus alba, Frankia, 15N fixation.

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Côté, Benoît y Jeffrey O. Dawson. "Effects of temperature regime and fertilization on nitrogenase activity of black alder seedlings during autumn in Illinois, U.S.A." Canadian Journal of Forest Research 19, n.º 12 (1 de diciembre de 1989): 1644–47. http://dx.doi.org/10.1139/x89-250.

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A pot experiment was conducted to determine the effects of two regimes of temperature and fertilization on nitrogenase activity (acetylene reduction) of naturalized black alder (Alnusglutinosa (L.) Gaertn.) seedlings during autumn in central Illinois, United States. An equal number of Frankia-nodulated plants were fertilized with either a complete or a nitrogen-free fertilizer solution. After 3 months of growth in a glasshouse, half of the plants in each fertilization group were transferred outside in mid-September. Rates of C2H2 reduction decreased throughout autumn for plants in all treatments, although exposure to freezing temperatures accelerated the decline of nitrogenase activity. Alders that did not receive nitrogen fertilization were still reducing C2H2 under natural light conditions in the heated glasshouse on December 10 at a rate of 7.5 nmol•mg−1•h−1. Compared with alders not receiving mineral nitrogen, complete fertilization resulted in a 45% reduction of initial autumnal rates of C2H2 reduction and early inactivity of nitrogenase. Leaf senescence and leaf abscission of naturalized black alder were not induced by decreasing photoperiod alone in Illinois. We conclude that N2 fixation of black alder in Illinois can proceed late into the autumn as long as green leaves remain attached to the plant and nodules are not subjected to low and freezing temperatures.

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Domenach, A. M., F. Kurdali, C. Danière y R. Bardin. "Détermination de l'identité isotopique de l'azote fixé par le Frankia associé au genre Alnus". Canadian Journal of Botany 66, n.º 7 (1 de julio de 1988): 1241–47. http://dx.doi.org/10.1139/b88-177.

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To use the 15N natural abundance method to evaluate the symbiotic nitrogen fixation by actinorhizal trees, it is necessary to determine the isotopic identity of assimilated nitrogen from two sources: the soil and the air. This study reports an isotopic value of fixed nitrogen by two alder species (Alnus incana (L.) Moench and Alnus glutinosa (L.) Gaertn. growing on nitrogen-free medium in greenhouse experiments. The δ15N value of the aerial parts was −2. This value was stable with time and did not depend on the Frankia strains used. This value could be used to estimate the nitrogen fixation in the natural ecosystem. Other parameters such as the mobilization of nitrogen reserves and the choice of the reference plant must be investigated to apply this method. The nodules of these two alder species were enriched in 15N relative to the rest of the plant but there was no relationship between symbiotic effectiveness of Frankia strains and 15N enrichment of nodules. On the other hand, for naturally growing trees, an enrichment in 15N was found primarily in the vesicles of nodules that are the sites of nitrogen fixation.

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Roy, Sébastien, Damase P. Khasa y Charles W. Greer. "Combining alders, frankiae, and mycorrhizae for the revegetation and remediation of contaminated ecosystems". Canadian Journal of Botany 85, n.º 3 (marzo de 2007): 237–51. http://dx.doi.org/10.1139/b07-017.

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Alder shrubs and trees that are capable of forming symbioses with mycorrhizal fungi and the nitrogen-fixing actinomycete Frankia sp. are particularly hardy species found worldwide in harsh and nutrient-deficient ecosystems. The mycorrhizal symbiosis may assist alders in nutrient and water uptake, while the actinorhizal symbiosis provides assimilable nitrogen. It is through these highly efficient symbioses, in which microsymbionts benefit from plant photosynthates, that actinorhizal plants such as alders colonize poor substrates, enrich soil, and initiate plant succession. These natural capabilities, combined with careful screening of microsymbionts and host plants, may prove useful for the rehabilitation of disturbed ecosystems. Although alders have been used extensively at industrial scales in forestry, nurse planting, and contaminated land revegetation, relatively little research has focussed on their actinorhizal and mycorrhizal plant–microbe interactions in contaminated environments. To study such a topic is, however, critical to the successful development of phytotechnologies, and to understand the impact of anthropogenic stress on these organisms. In this review, we discuss two alder-based phytotechnologies that hold promise: the stimulation of organic contaminant biodegradation (rhizodegradation) by soil microflora in the presence of alders, and the phytostabilization of inorganic contaminants. We also summarize the plant–microbe interactions that characterize alders, and discuss important issues related to the study of actinorhizal and (or) mycorrhizal alders for the rehabilitation of disturbed soils.

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Markham, John H. y Chris P. Chanway. "Does past contact reduce the degree of mutualism in the Alnus rubra - Frankia symbiosis?" Canadian Journal of Botany 77, n.º 3 (20 de agosto de 1999): 434–41. http://dx.doi.org/10.1139/b98-227.

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Although most vascular plants have symbiotic relationships with soil microbes, and there is an extensive theoretical literature on the evolution of mutualism, there has been little experimental examination of the evolution of mutualism between plants and their microbial symbionts. We inoculated red alder (Alnus rubra Bong.) seedlings from three high- and three low-elevation populations with crushed nodule suspensions containing the nitrogen fixing bacterium Frankia from either the parent trees (familiar strains) or the other plant population sampled within the parent watershed (unfamiliar strains). The inoculated seedlings were planted on three high- and three low-elevation sites. Growth was monitored over the second and third year following planting, after which the whole plants were harvested. The proportion of nitrogen derived from fixation was estimated from the ratio of stable nitrogen isotopes in the harvested leaves. On low-elevation sites, which had high soil nitrogen, plants with familiar Frankia strains were half the size and derived less fixed nitrogen from their symbionts compared with plants inoculated with unfamiliar Frankia strains. On high-elevation sites, which had low soil nitrogen, the type of inoculum had little effect on plant performance, although plants with familiar inoculum were consistently larger than plants with unfamiliar inoculum. These results suggest that the degree of mutualism in this symbiosis depends on environmental conditions and may decrease with time.Key words: coevolution, Frankia, Alnus rubra, mutualism, nitrogen fixation, symbiosis.

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Lefrançois, Elisabeth, Ali Quoreshi, Damase Khasa, Martin Fung, Lyle G. Whyte, Sébastien Roy y Charles W. Greer. "Field performance of alder-Frankia symbionts for the reclamation of oil sands sites". Applied Soil Ecology 46, n.º 2 (octubre de 2010): 183–91. http://dx.doi.org/10.1016/j.apsoil.2010.08.010.

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Kratsch, Heidi A. y William R. Graves. "Location and Anatomy of Nodules on Alnus maritima Subjected to Flooding". Journal of the American Society for Horticultural Science 129, n.º 6 (noviembre de 2004): 775–80. http://dx.doi.org/10.21273/jashs.129.6.0775.

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Although many species of Alnus Miller grow in wet soils, none is as closely associated with low-oxygen, waterlogged soils as Alnus maritima (Marsh.) Muhl. ex Nutt. (seaside alder). An actinorhizal species with promise for use in horticultural landscapes, land reclamation, and sustainable systems, A. maritima associates with Frankia Brunchorst, thereby forming root nodules in which gaseous nitrogen is fixed. Our objective was to determine how root-zone moisture conditions influence the occurrence, location, and anatomy of nodules on A. maritima. Plants of Alnus maritima subsp. maritima Schrader and Graves were established in root zones with compatible Frankia and subjected to four moisture regimens (daily watered/drained, partially flooded, totally flooded, and totally flooded with argon bubbled through the flood water) for 8 weeks. Oxygen content of the root zone, number and location of nodules on root systems, and dry weight and nitrogen content of shoots were determined. Root-zone oxygen content ranged from 17.3 kPa for daily watered/drained plants to 0.9 kPa for argon-treated plants. Across all treatments, 87% of the nodules were within the upper one-third (4 cm) of the root zone. Although shoot dry weights of daily watered/drained and partially flooded plants were not different, daily watered/drained plants had more nitrogen in their leaves (2.53 vs. 2.21 mg·g-1). Nodulation occurred in all treatments, but nodules on totally flooded roots (with or without argon) were limited to a single lobe; in contrast, multilobed nodules were prevalent on partially flooded and daily watered/drained plants. Frankia infection within submerged nodule lobes was limited to one or two layers of cortical cells. Submerged nodules developed large air spaces between cortical cells, and phenolic-containing cells appeared to inhibit Frankia expansion within the nodule. These data suggest that access to root-zone oxygen is critical to the Frankia-A. maritima subsp. maritima symbiosis, and that plants of this subspecies in the drained soils of managed landscapes may benefit more than plants in native wetland habitats from nodulation and nitrogen fixation.

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Rojas, Nestor S., David A. Perry, C. Y. Li y Jacob Friedman. "Influence of actinomycetes on Frankia infection, nitrogenase activity and seedling growth of red alder". Soil Biology and Biochemistry 24, n.º 10 (octubre de 1992): 1043–49. http://dx.doi.org/10.1016/0038-0717(92)90034-u.

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Zekveld, Corinthe y John Markham. "Exposure to aphids increases alder growth and nitrogen fixation". Botany 89, n.º 4 (abril de 2011): 255–61. http://dx.doi.org/10.1139/b11-012.

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Plants can respond to herbivore damage by mounting a resistance response or by compensating for lost fitness. Both plant nutrition and interactions with soil microbes can affect these responses. It has been shown that resistance responses can occur before plants have been attacked by herbivores. Here we show that a tolerance type of response can occur when plants are exposed to, but not fed on by, herbivores. Alnus viridis (Chaix) DC. spp. crispa (Ait.) Turrill were grown in sealed containers under positive air pressure with either 0.5 mmol·L–1 or 2.0 mmol·L–1 nitrate and either inoculated or not inoculated with Frankia , their nitrogen-fixing symbiont. Plants were then exposed to the genus-specific aphid Prociphilus tessallatus Fitch, which failed to establish feeding colonies. Exposure to aphids, formation of nitrogen-fixing nodules, and elevated soil nitrogen levels all significantly increased plant yield with no interaction among these factors. A combination of high soil nitrogen, nodulation, and exposure to aphids resulted in the lowest plant root:shoot ratio. Plants that were grown with low nitrogen and were exposed to aphids showed increased nitrogen-fixing activity within a day of being exposed. These results provide further evidence to support the observation that plants can respond to cues from other organisms prior to receiving herbivore damage.

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Brunner, I. L., F. Brunner y O. K. Miller Jr. "Ectomycorrhizal synthesis with Alaskan Alnus tenuifolia". Canadian Journal of Botany 68, n.º 4 (1 de abril de 1990): 761–67. http://dx.doi.org/10.1139/b90-101.

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The ability of Alnus tenuifolia to form ectomycorrhizae with potential ectomycorrhizal fungi was investigated. Alnus tenuifolia seedlings raised in growth pouches were inoculated with Frankia to induce nodulation and then with a putative ectomycorrhizal fungus. The fungi used were collected in nearly pure A. tenuifolia stands in Alaska or were found in Alnus nepalensis stands in Nepal. Five species of putative ectomycorrhizal symbionts of alders were tested. Alpova diplophloeus and Paxillus filamentosus formed both mantle and Hartig net. Cortinarius cf. saturninus developed a mantle but no Hartig net. Hebeloma cf. crustuliniforme and Gyrodon lividus developed neither mantle nor Hartig net. This is the first report of synthesis of P. filamentosus and C. cf. saturninus with Alnus. The ectomycorrhizal status of the genus Gyrodon is discussed, since in vitro synthesis has not yet been demonstrated. Synthesis with A. diplophloeus and H. crustuliniforme did not result in ectomycorrhizal formations with nonnodulated alder seedlings.

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Beddes, Taun y Heidi A. Kratsch. "Nodulation of Seaside Alder Topdressed with Controlled-release Fertilizer". HortTechnology 20, n.º 4 (agosto de 2010): 740–45. http://dx.doi.org/10.21273/horttech.20.4.740.

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Seaside alder (Alnus maritima) is a rare species adapted for ornamental use. It can be produced easily by commercial growers, and when soil-inoculated in nursery containers, will form root nodules containing nitrogen (N)-fixing bacteria in the genus Frankia. It has been demonstrated that nodulation within this species can be controlled by the amount of N plants receive from a liquid source; however, granular controlled-release fertilizers (CRF) also are commonly used by commercial growers, and information is not available on CRF effects on nodulation. We sought to determine the application rate of CRF that will maximize nodulation of seaside alder while sustaining acceptable plant health and growth. Inoculated containerized plants were topdressed with CRF at eight application rates from 0 to 32.0 g per container. A control group of uninoculated plants received the manufacturer's prescribed rate of 6.0 g per 6-inch-diameter standard round pot. Regression analysis revealed that treatment with 2.0 g of CRF maximized root nodule formation (a mean of 26 nodules), while nodulation was inhibited at CRF rates ≥4.0 g. Plant growth parameters and leaf N content of inoculated plants treated with 2.0 g of CRF were similar to those of uninoculated plants receiving the prescribed rate of CRF (P < 0.05); nitrate-nitrogen leaching from pots containing 2.0-g CRF-treated plants was minimal. We conclude that vigorous nodulated plants of seaside alder can be produced, with minimal nitrate leaching, by providing CRF at lower than prescribed rates.

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23

Sequerra, Jeanine, André Capellano, Monique Faure-Raynard y André Moiroud. "Root hair infection process and myconodule formation on Alnus incana by Penicillium nodositatum". Canadian Journal of Botany 72, n.º 7 (1 de julio de 1994): 955–62. http://dx.doi.org/10.1139/b94-121.

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Penicillium nodositatum infects the roots of alder trees and induces the formation of structures called myconodules, which are similar to young actinorhizae. Root infection of Alnus incana by P. nodositatum as well as myconodule development were studied by light and electron microscopy and observations were compared with those described for the infection by Frankia spp. We have established an obvious homology between the early steps of the infection caused by both microorganisms. The presence of the fungus near the roots induces deformation of root hairs. The infection site is probably localized in a folding of a deformed hair. As soon as hyphae penetrate into the hair, they become enclosed in a polysaccharide matrix. Initially, P. nodositatum colonizes a region near the infected root hair that may correspond to a slightly developed prenodule. Then a nodular primordium is initiated at some distance from the initial contact and the new nodular cortex is invaded by the fungus. The zone of infection is limited to the cortical cells by a barrier of tannins. Myconodules remain small and unilobed and have an outer morphology similar to that of an incompatible Frankia nodule. Key words: Alnus, myconodule formation, Penicillium, root hair infection.

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24

Xia, Chenxi, Wanglin Zhao, Jinniu Wang, Jian Sun, Guangshuai Cui y Lin Zhang. "Progress on Geographical Distribution, Driving Factors and Ecological Functions of Nepalese Alder". Diversity 15, n.º 1 (4 de enero de 2023): 59. http://dx.doi.org/10.3390/d15010059.

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As the oldest species of Betulaceae, Nepalese alder (Alnus nepalensis) shows a high capacity for nitrogen fixation, rapid growth rate, and strong adaptability to stress environments, and it plays an important role in maintaining the structure and function of forest and agroforestry ecosystems. We explored its geographic distribution and the corresponding environmental drivers through collecting specimen records and published literature for Nepalese alder over the world during the past 40 years. The research trends, the growth limiting factors, the physiological characteristics, and ecological functions were all summarized as well. In terms of geographical distribution and limiting factors, Nepalese alder is mainly distributed in southern mountainous areas of the Himalayas and southwest China. Since it presented a clear northern limit of distribution and an upper limit of elevation, temperature is assumed to be the main environmental limiting factor. According to historical development, the research history of Nepalese alder could be divided into three main periods: the initial development (before 2001), the fast development (2002–2015), and the high-quality development (2016–2022), with the two key points in 2002 and 2015 relating to the conversion of cropland to a forest project that the government conducted and the application from theory to practice, respectively. As can be seen from the ecological functions, Nepalese alder could form symbiotic nodules with Frankia, which plays an important role in improving soil physical and chemical properties and facilitating vegetation secondary succession. Overall, the present review provides a reference for further studies on ecological adaptability and sustainable utilization of Nepalese alder under climate change, and also for regional ecosystem service, forestry production practice, and vegetation restoration.

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25

Quoreshi, A. M., S. Roy, C. W. Greer, J. Beaudin, D. McCurdy y D. P. Khasa. "Inoculation of green alder ([Alnus crispa]) with Frankia-Ectomycorrhizal Fungal Inoculant Under Commercial Nursery Production Conditions". Native Plants Journal 8, n.º 3 (1 de septiembre de 2007): 271–81. http://dx.doi.org/10.2979/npj.2007.8.3.271.

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26

Benoit, Larry F. y Alison M. Berry. "Flavonoid-like compounds from seeds of red alder (Alnus rubra) influence host nodulation by Frankia (Actinomycetales)". Physiologia Plantarum 99, n.º 4 (abril de 1997): 588–93. http://dx.doi.org/10.1111/j.1399-3054.1997.tb05361.x.

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27

Benoit, Larry F. y Alison M. Berry. "Flavonoid-like compounds from seeds of red alder (Alnus rubra) influence host nodulation by Frankia (Actinomycetales)*". Physiologia Plantarum 99, n.º 4 (abril de 1997): 588–93. http://dx.doi.org/10.1034/j.1399-3054.1997.990410.x.

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28

Simonet, P., M. Bosco, C. Chapelon, A. Moiroud y P. Normand. "Molecular characterization of Frankia microsymbionts from spore-positive and spore-negative nodules in a natural alder stand." Applied and Environmental Microbiology 60, n.º 4 (1994): 1335–41. http://dx.doi.org/10.1128/aem.60.4.1335-1341.1994.

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29

Martin, K. J., Y. Tanaka y D. D. Myrold. "Peat carrier increases inoculation success with Frankia on red alder (Alnus rubra Bong.) in fumigated nursery beds". New Forests 5, n.º 1 (1991): 43–50. http://dx.doi.org/10.1007/bf00037550.

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30

Burgess, D. y R. L. Peterson. "Effect of nutrient conditions on root nodule development in Alnus japonica". Canadian Journal of Botany 65, n.º 8 (1 de agosto de 1987): 1658–70. http://dx.doi.org/10.1139/b87-227.

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The morphology and structure of nodules on the exotic tree alder Alnus japonica (Thunb.) Steud. inoculated with the North American Frankia strain HFPArI3 were examined under different nutrient conditions. Seedlings were subjected to a nitrogen, phosphorus, or iron stress treatment using the Ingestad nutrient addition technique which generally produced a decrease in the length of healthy endophytic vesicle cluster zones. External nodule morphology varied according to treatment, with thicker nodules developing under "good" nutrient conditions. Nodule meristems showed apparent apical dominance under conditions of nutrient stress. Increased additions of inorganic nitrogen reduced the levels of nitrogen fixation and increased cortical cell size but reduced the numbers of endopytic vesicles per unit area. High nitrogen fixation levels were accompanied by the formation of numerous large mitochondria in nodule pericycle cells.

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31

Crannell, Wanda K., Yasu Tanaka y David D. Myrold. "Calcium and pH interaction on root nodulation of nursfry-grown red alder (Alnus rubra bong.) seedlings by Frankia". Soil Biology and Biochemistry 26, n.º 5 (mayo de 1994): 607–14. http://dx.doi.org/10.1016/0038-0717(94)90249-6.

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32

Ballhorn, Daniel J., Jacob D. Elias, M. A. Balkan, Rachel F. Fordyce y Peter G. Kennedy. "Colonization by nitrogen-fixing Frankia bacteria causes short-term increases in herbivore susceptibility in red alder (Alnus rubra) seedlings". Oecologia 184, n.º 2 (20 de mayo de 2017): 497–506. http://dx.doi.org/10.1007/s00442-017-3888-2.

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33

Gaulke, Linda S., Charles L. Henry y Sally L. Brown. "Nitrogen fixation and growth response of Alnus Rubra following fertiliztion with urea or biosolids". Scientia Agricola 63, n.º 4 (agosto de 2006): 361–69. http://dx.doi.org/10.1590/s0103-90162006000400007.

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Nitrogen fertilization of forests using biosolids offers a potentially environmentally friendly means to accelerate tree growth. This field study was designed to analyze the effects of nitrogen fertilization on the symbiotic, nitrogen (N)-fixing relationship between Alnus rubra Bong. (red alder) and Frankia. Anaerobically digested, class B biosolids and synthetic urea (46% N) were applied at rates of 140, 280 and 560 kg ha-1 available N to a well-drained, sandy, glacial outwash soil in the Indianola series (mixed, mesic Dystric Xeropsamments). Plots were planted with A. rubra seedlings. At the end of each of two growing seasons trees were harvested and analyzed for the rate of N fixation (as acetylene reduction activity), biomass and foliar N. At year 1, there was no N fixation for trees grown with urea amendments, but control (17 µmol C2H4 g-1 hr-1) and biosolids (26-45 µmol C2H4 g-1 hr-1) trees were fixing N. At the end of year 2, all trees in all treatments were fixing N (7 µmol C2H4 g-1 hr-1, 4-16 µmol C2H4 g-1 hr-1, and 20-29 µmol C2H4 g-1 hr-1 for control, urea and biosolids respectively). Trees grown with biosolids amendments were larger overall (year 1 shoot biomass 10 g, 5 g, and 23 g for control, urea, and biosolids respectively, year 2 shoot biomass 50 g, 51 g, and 190 g for control, urea, and biosolids respectively) with higher concentrations of foliar N for both years of the study (year 1 foliar N 26 g kg-1, 27 g kg-1, and 40 g kg-1 for control, urea, and biosolids respectively, year 2 foliar N 17 g kg-1, 19 g kg-1, and 23 g kg-1 for control, urea, and biosolids respectively). Trees grown with urea amendments appeared to use the urea N over Frankia supplied N, whereas the biosolids trees appeared to be able to use both N in biosolids and N from Frankia. The results from this study indicated that the greater growth of A. rubra may have been responsible for the observed higher N demand. Biosolids may have supplied other nutrients to the trees to support this accelerated growth.

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34

Miller, Steven L., C. D. Koo y Randy Molina. "Early colonization of red alder and Douglas fir by ectomycorrhizal fungi and Frankia in soils from the Oregon coast range". Mycorrhiza 2, n.º 2 (diciembre de 1992): 53–61. http://dx.doi.org/10.1007/bf00203250.

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35

Lumini, Erica, Marco Bosco, Gigliola Puppi, Raffaella Isopi, Mauro Frattegiani, Enrico Buresti y Franco Favilli. "Field performance of Alnus cordata loisel (Italian alder) inoculated with Frankia and VA-mycorrhizal strains in mine-spoil afforestation plots". Soil Biology and Biochemistry 26, n.º 5 (mayo de 1994): 659–61. http://dx.doi.org/10.1016/0038-0717(94)90256-9.

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36

Moffat, A. J. "Effects of inoculation with Frankia on the growth and nutrition of alder species and interplanted Japanese larch on restored mineral workings". Forestry 73, n.º 3 (1 de marzo de 2000): 215–23. http://dx.doi.org/10.1093/forestry/73.3.215.

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37

Laws*, Michele Tiffany y William R. Graves. "Long- and Short-term Effects of Nitrogen on Formation and Function of Root Nodules on Alnus maritima". HortScience 39, n.º 4 (julio de 2004): 892C—892. http://dx.doi.org/10.21273/hortsci.39.4.892c.

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Symbiotic associations between Alnus maritima (Marsh.) Muhl. ex Nutt. (seaside alder) and the actinomycete Frankia result in root nodules in which atmospheric nitrogen (N) is fixed. This has led to interest in producing seaside alders with minimal N fertilizer and in using the species on low-N soils. Our objectives were to determine how applied N influences nodulation and to characterize how short-term changes in root-zone N affect the function of established nodules. Seaside alders native to the Delmarva Peninsula (Alnus maritima subsp. maritima) were grown in perlite inoculated with soil from roots of indigenous plants. Plants were treated with N-free Hoagland solution supplemented with ammonium nitrate at 0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 2, 4, and 8 mm for 10 weeks. Nodulation decreased as applied N increased. While plants treated with ammonium nitrate at 4 and 8 mm formed nearly no nodules, 0.5 mM resulted in vigorous, healthy plants that formed, on average, 70 nodules. In a second experiment, a nodulated population of seaside alders was established by treating seedlings with 0.5-mm ammonium nitrate in otherwise N-free Hoagland solution for 6 weeks. Plants then were provided ammonium nitrate at 0.5, 2, or 4 mm for two weeks. Acetylene-reduction assays showed that ammonium nitrate at 4 mm suppressed nodule activity. Daily irrigation with N-free solution subsequently led to a rapid depletion of root-zone N and a concomitant resurgence of nodule activity among plants previously provided 2- and 4-mm ammonium nitrate. These results provide useful information on how to manage fertility to optimize nodulation and show suppression of nodule activity caused by N fertilization can be temporary if excess N is leached from the root zone.

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38

Yamanaka, Takashi, Ching-Y. Li, Bernard T. Bormann y Hiroaki Okabe. "Tripartite associations in an alder: effects of Frankia and Alpova diplophloeus on the growth, nitrogen fixation and mineral acquisition of Alnus tenuifolia". Plant and Soil 254, n.º 1 (julio de 2003): 179–86. http://dx.doi.org/10.1023/a:1024938712822.

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39

Lopez, Mary F., Patricia Young y John G. Torrey. "A comparison of carbon source utilization for growth and nitrogenase activity in two Frankia isolates". Canadian Journal of Microbiology 32, n.º 4 (1 de abril de 1986): 353–58. http://dx.doi.org/10.1139/m86-068.

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The carbon source requirements for the growth and nitrogen fixation of two morphologically distinct Frankia isolates were examined. Isolate ArI3 (from Alnus rubra) grew well on propionate, malate, acetate, and trehalose, and isolate CcI2 (from Casuarina cunninghamiana) grew best on pyruvate, acetate, and propionate. In general, the same carbon sources that supported growth supported both the development of vesicles and nitrogenase activity in long-term induction experiments in both isolates. However, ArI3 cultures induced on proprionate had 7 to 26 times the activity of other carbon sources and ArI3 cultures induced on acetate did not develop any detectable acetylene reduction. In a parallel set of experiments, cultures of both isolates were induced for nitrogenase activity on propionate and the resulting nitrogen fixing cultures were washed free of the organic acid by centrifugation. The washed cultures were incubated in the presence of various carbon sources to determine the ability of a particular substrate to supply energy directly for nitrogen fixation when vesicles and nitrogenase were already present. As was observed in the long-term induction experiments, pyruvate, propionate, and acetate supported the greatest activity in CcI2. Succinate and malate supported the greatest activity in ArI3, and propionate had very little stimulation of acetylene reduction. The reason for the lack of stimulation by propionate for washed cells of ArI3 was unclear but may have been due to toxic concentrations of the organic acid. In an attempt to compare the carbon utilization of ArI3 in pure culture with that in the alder symbiosis, oxygen uptake in the presence of various carbon sources of vesicles clusters isolate from Alnus rubra nodules inoculated with ArI3 was compared with the oxygen uptake of nitrogen-fixing pure cultures of ArI3. The oxygen uptake of the isolated vesicle clusters was stimulated by sucrose, trehalose, and glucose, but not by a variety of organic acids. In comparison, nitrogen-fixing pure cultures of ArI3 readily oxidized sugars and organic acids.

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40

Rojas, N. S., C. Y. Li, D. A. Perry y L. M. Ganio. "Frankia and nodulation of red alder and snowbrush grown on soils from Douglas-fir forests in the H.J. Andrews experimental forest of Oregon". Applied Soil Ecology 17, n.º 2 (junio de 2001): 141–49. http://dx.doi.org/10.1016/s0929-1393(01)00127-5.

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41

Gaulke, Linda S., Charles L. Henry y Sally L. Brown. "Nitrogen fixation and growth response of Alnus rubra amended with low and high metal content biosolids". Scientia Agricola 63, n.º 4 (agosto de 2006): 351–60. http://dx.doi.org/10.1590/s0103-90162006000400006.

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Forest application of biosolids offers a potential environmentally friendly alternative to landfilling. This two-year investigation was designed to analyze the effects of elevated soil metal concentration resulting from the land application of biosolids on the symbiotic, nitrogen (N) fixing relationship between Alnus rubra Bong. (red alder) and Frankia. High metal biosolids and a modern-day composted biosolid applied at high loading rates of 250, 500, and 1000 Mg ha-1, were used to represent a worst-case scenario for metal contamination. The high metal biosolids were obtained before the current regulations were formulated and had been lagooned prior to use in this study. Total cadmium (Cd), lead (Pb) and zinc (Zn) in the high metal biosolids were 45, 958, and 2623 mg kg-1 respectively. These metal concentrations are above current regulatory limits in the US. The compost was made using biosolids that are currently produced and had Cd, Pb and Zn of 0.8, 20 and 160 mg kg-1 respectively. Trees were harvested and analyzed for rate of N fixation (as measured by acetylene reduction activity), biomass, and foliar metals. Soils were analyzed for available N, total carbon and N, pH and total Cd, Pb and Zn. Rates of N fixation were not affected by soil amendment. In year 2, shoot biomass of trees grown in both the compost and high metal amendments were higher than the control. Shoot biomass increased with increasing amount of compost amendments, but decreased with increasing amount of high metal amendments. There was no relationship between soil metal concentration and plant biomass. Foliar Cd and Pb were below detection for all trees and foliar Zn increased with increasing amount of both compost and high metal amendment, with concentrations of 249 mg kg-1 for trees grown in the compost amendment and 279 mg kg-1 for the high metal amendment. The results from this study indicate that the growth of A. rubra benefited from both types of biosolids used in the study and that the Alnus/Frankia relationship was not negatively impacted by metal concentrations resulting from the high metal biosolids amendments.

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42

Gagnon, Vanessa, Michaël Rodrigue-Morin, Julien Tremblay, Jessica Wasserscheid, Julie Champagne, Jean-Philippe Bellenger, Charles W. Greer y Sébastien Roy. "Vegetation drives the structure of active microbial communities on an acidogenic mine tailings deposit". PeerJ 8 (21 de octubre de 2020): e10109. http://dx.doi.org/10.7717/peerj.10109.

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Plant-microbe associations are increasingly recognized as an inextricable part of plant biology and biogeochemistry. Microbes play an essential role in the survival and development of plants, allowing them to thrive in diverse environments. The composition of the rhizosphere soil microbial communities is largely influenced by edaphic conditions and plant species. In order to decipher how environmental conditions on a mine site can influence the dynamics of microbial communities, we characterized the rhizosphere soil microbial communities associated with paper birch, speckled alder, and spruce that had naturally colonized an acidogenic mine tailings deposit containing heavy metals. The study site, which had been largely undisturbed for five decades, had highly variable vegetation density; with some areas remaining almost barren, and others having a few stands or large thickets of mature trees. Using Illumina sequencing and ordination analyses (redundancy analysis and principal coordinate analysis), our study showed that soil bacterial and fungal community structures correlated mainly with vegetation density, and plant species. Tailings without any vegetation were the most different in bacterial community structure, compared to all other areas on the mine site, as well as an adjacent natural forest (comparison plot). The bacterial genera Acidiferrobacter and Leptospirillum were more abundant in tailings without vegetation than in any of the other sites, while Bradyrhizobium sp. were more abundant in areas of the tailings deposit having higher vegetation density. Frankia sp. is equally represented in each of the vegetation densities and Pseudomonas sp. present a greater relative abundance in boreal forest. Furthermore, alder rhizosphere showed a greater relative abundance of Bradyrhizobium sp. (in comparison with birch and spruce) as well as Haliangium sp. (in comparison with birch). In contrast, fungal community structures were similar across the tailings deposit regardless of vegetation density, showing a greater relative abundance of Hypocrea sp. Tailings deposit fungal communities were distinct from those found in boreal forest soils. Alder rhizosphere had greater relative abundances of Hypocrea sp. and Thelephora sp., while birch rhizosphere were more often associated with Mollisia sp. Our results indicate that, with increasing vegetation density on the mine site, the bacterial communities associated with the individual deciduous or coniferous species studied were increasingly similar to the bacterial communities found in the adjacent forest. In order to properly assess and restore disturbed sites, it is important to characterize and understand the plant-microbe associations that occur since they likely improve plant fitness in these harsh environments.

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43

Laws, M. Tiffany y William R. Graves. "Nitrogen Inhibits Nodulation and Reversibly Suppresses Nitrogen Fixation in Nodules of Alnus maritima". Journal of the American Society for Horticultural Science 130, n.º 4 (julio de 2005): 496–99. http://dx.doi.org/10.21273/jashs.130.4.496.

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Symbiotic associations between Alnus maritima (Marsh.) Muhl. ex Nutt. (seaside alder) and actinomycetes in the genus Frankia Brunchorst result in root nodules in which atmospheric nitrogen (N) is fixed. The economic and environmental benefits of N fixation have led to interest in inducing root nodules during production of A. maritima. Because woody plants produced in nurseries typically are provided N fertilizer, our objectives were to determine how applied N influences nodulation of A. maritima and to characterize how short-term changes in root-zone N affect the function of nodules. Potted seedlings were grown in perlite that was inoculated with 30 mL of soil from the root zones of mature plants in their native habitat on the Delmarva Peninsula. Each pot was drenched once daily for 10 weeks with nutrient solution that contained ammonium nitrate at 10 concentrations from 0 to 8 mm. Plants that received no ammonium nitrate formed the most nodules, and nodulation decreased linearly as ammonium nitrate increased from 0.25 to 4 mm. Plants treated with ammonium nitrate at 4 or 8 mm formed nearly no nodules, while ammonium nitrate at 0.5 mm resulted in vigorous plants with an average nodule count of 70. In a second experiment, a population of nodulated seaside alders was established by irrigating seedlings in inoculated perlite once daily with 0.5-mm ammonium nitrate for 6 weeks. Plants then were provided ammonium nitrate at 0.5, 2, or 4 mm for 2 weeks. Acetylene-reduction assays showed suppressed nodule activity among plants provided 2- and 4-mm ammonium nitrate. Daily irrigation of those plants with N-free solution subsequently led to a rapid depletion of root-zone N and to a concomitant resurgence of nodule activity. These results demonstrate that N fertilization can be managed to promote nodulation of A. maritima and show that decreased nodule activity caused by short-term increases in root-zone N is reversible.

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44

Kikuchi, Yoshitomo, Takahiro Hosokawa y Takema Fukatsu. "Insect-Microbe Mutualism without Vertical Transmission: a Stinkbug Acquires a Beneficial Gut Symbiont from the Environment Every Generation". Applied and Environmental Microbiology 73, n.º 13 (4 de mayo de 2007): 4308–16. http://dx.doi.org/10.1128/aem.00067-07.

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ABSTRACT The broad-headed bug Riptortus clavatus (Heteroptera: Alydidae) possesses a number of crypts at a posterior midgut region, which house a dense population of a bacterial symbiont belonging to the genus Burkholderia. Although the symbiont is highly prevalent (95 to 100%) in the host populations, the symbiont phylogeny did not reflect the host systematics at all. In order to understand the mechanisms underlying the promiscuous host-symbiont relationship despite the specific and prevalent association, we investigated the transmission mode and the fitness effects of the Burkholderia symbiont in R. clavatus. Inspection of eggs and a series of rearing experiments revealed that the symbiont is not vertically transmitted but is environmentally acquired by nymphal insects. The Burkholderia symbiont was present in the soil of the insect habitat, and a culture strain of the symbiont was successfully isolated from the insect midgut. Rearing experiments by using sterilized soybean bottles demonstrated that the cultured symbiont is able to establish a normal and efficient infection in the host insect, and the symbiont infection significantly improves the host fitness. These results indicated that R. clavatus postnatally acquires symbiont of a beneficial nature from the environment every generation, uncovering a previously unknown pathway through which a highly specific insect-microbe association is maintained. We suggest that the stinkbug-Burkholderia relationship may be regarded as an insect analogue of the well-known symbioses between plants and soil-associated microbes, such as legume-Rhizobium and alder-Frankia relationships, and we discuss the evolutionary relevance of the mutualistic but promiscuous insect-microbe association.

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Zimpfer, J. F., G. J. Kennedy, C. A. Smyth, J. Hamelin, E. Navarro y J. O. Dawson. "Localization ofCasuarina-infectiveFrankianearCasuarina cunninghamianatrees in Jamaica". Canadian Journal of Botany 77, n.º 9 (18 de diciembre de 1999): 1248–56. http://dx.doi.org/10.1139/b99-063.

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Soil sampled along a 100-m linear series of plots extending from the stems of three Casuarina cunninghamiana Miq. trees was bioassayed to estimate the number of infective units (IU) of the symbiotic diazotroph Frankia per gram of soil using native Myrica cerifera L. and exotic C. cunninghamiana as Frankia traps. Casuarina-infective Frankia was detected only in soils within 20 m of Casuarina host trees. Myrica-infective Frankia was found in all of the plots assayed even though none of the native M. cerifera occurred on or near the site. Polymerase chain reaction - restriction fragment length polymorphism characterization of nodule microsymbiont DNA from both host species indicates that Casuarina were nodulated by a different group of Frankia than the groups nodulating Myrica. The Casuarina-infective Frankia is in the same taxonomic group as most other Casuarina-infective Frankia found where Casuarina trees were introduced outside of Australia. Soil collected near the C. cunninghamiana trees had higher total N, NO3, organic matter, P, Mg, K, Ca, pH, and cation exchange capacity. Homogenates ofC. cunninghamiana leaves and stems increased the number of IUs of Frankia CjI82 001 when inoculated and incubated for 3 months in an artificial soil. Thus, it seems that C. cunninghamiana is able to alter soil chemical properties and possibly favor its specific microsymbiont in soil.Key words: Frankia, Casuarina, Myrica, symbiosis, allelopathy, N-fixation.

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46

Weirich, Steffen, Martin Reinhardt, Johannes Buchmann, Alexander Dück, Jacqueline Höppner, Rainer Hofmockel, Michael Grözinger y Frank Häßler. "Elektrokonvulsionstherapie – bei Kindern und Jugendlichen mit Schizophrenie wirksam und gut verträglich". Fortschritte der Neurologie · Psychiatrie 88, n.º 08 (11 de mayo de 2020): 495–99. http://dx.doi.org/10.1055/a-0921-6792.

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ZusammenfassungWir berichten über vier Patienten im Alter von 12 bis 17 Jahren mit schizophrenen Psychosen, zwei davon mit katatoner Symptomatik, die erfolgreich und sicher mit Elektrokonvulsionstherapie (EKT) behandelt wurden. Unter einer kombinierten Therapie aus EKT und entweder Ziprasidon oder Clozapin verbesserte sich der Zustand aller Patienten erheblich. Schweregrad und Verlauf der akuten Schizophrenie wurden mit der Brief Psychiatric Rating Scale (BPRS) evaluiert. Schweregrad und Verlauf der Katatonie wurden mit der Bush-Francis Catatonia Rating Scale (BFCRS) gemessen. Die Fälle bestätigen frühere Berichte zur Wirksamkeit, zur Sicherheit und Verträglichkeit von EKT bei der Behandlung von Kindern und Jugendlichen mit Schizophrenie.

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47

McEwan, Neil R. "Autofluorescence as a diagnostic tool for the infection of alders by Frankia". Sciences of Soils 5, n.º 3 (agosto de 2000): 22–27. http://dx.doi.org/10.1007/s10112-000-0003-2.

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Beauchemin, Nicholas J., Teal Furnholm, Julien Lavenus, Sergio Svistoonoff, Patrick Doumas, Didier Bogusz, Laurent Laplaze y Louis S. Tisa. "Casuarina Root Exudates Alter the Physiology, Surface Properties, and Plant Infectivity of Frankia sp. Strain CcI3". Applied and Environmental Microbiology 78, n.º 2 (18 de noviembre de 2011): 575–80. http://dx.doi.org/10.1128/aem.06183-11.

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ABSTRACTThe actinomycete genusFrankiaforms nitrogen-fixing symbioses with 8 different families of actinorhizal plants, representing more than 200 different species. Very little is known about the initial molecular interactions betweenFrankiaand host plants in the rhizosphere. Root exudates are important inRhizobium-legume symbiosis, especially for initiating Nod factor synthesis. We measured differences inFrankiaphysiology after exposure to host aqueous root exudates to assess their effects on actinorhizal symbioses.Casuarina cunninghamianaroot exudates were collected from plants under nitrogen-sufficient and -deficient conditions and tested onFrankiasp. strain CcI3. Root exudates increased the growth yield ofFrankiain the presence of a carbon source, butFrankiawas unable to use the root exudates as a sole carbon or energy source. Exposure to root exudates caused hyphal “curling” inFrankiacells, suggesting a chemotrophic response or surface property change. Exposure to root exudates altered Congo red dye binding, which indicated changes in the bacterial surface properties at the fatty acid level. Fourier transform infrared spectroscopy (FTIR) confirmed fatty acid changes and revealed further carbohydrate changes.Frankiacells preexposed toC. cunninghamianaroot exudates for 6 days formed nodules on the host plant significantly earlier than control cells. These data support the hypothesis of early chemical signaling between actinorhizal host plants andFrankiain the rhizosphere.

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Trembinski, Donna C. "Non alter Christus: Early Dominican Lives of Saint Francis". Franciscan Studies 63, n.º 1 (2005): 69–105. http://dx.doi.org/10.1353/frc.2005.0002.

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Moret, Frédéric. "Utopie aller et retour : le Voyage from Utopia de John Francis Bray". Cahiers de Fontenay 69, n.º 1 (1993): 141–52. http://dx.doi.org/10.3406/cafon.1993.1615.

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