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Alnus acuminata is a keystone tree species in the Yungas forests and host to a wide range of fungal symbionts. While species distribution models (SDMs) are routinely used for plants and animals to study the effects of climate change on montane forest communities, employing SDMs in fungi has been hindered by the lack of data on their geographic distribution. The well-known host specificity and common biogeographic history of A. acuminata and associated ectomycorrhizal (ECM) fungi provide an exceptional opportunity to model the potential habitat for this symbiotic assemblage and to predict possible climate-driven changes in the future. We (1) modeled the present and future distributions of suitable habitats for A. acuminata; (2) characterized fungal communities in different altitudinal zones of the Yungas using DNA metabarcoding of soil and root samples; and (3) selected fungi that were significant indicators of Alnus. Fungal communities were strongly structured according to altitudinal forest types and the presence of Alnus. Fungal indicators of Alnus, particularly ECM and root endophytic fungi, were also detected in Alnus roots. Current and future (year 2050) habitat models developed for A. acuminata predict a 25–50 percent decrease in suitable area and an upslope shift of the suitable habitat by ca. 184–380 m, depending on the climate change scenario. Although A. acuminata is considered to be an effective disperser, recent studies suggest that Andean grasslands are remarkably resistant to forest invasion, and future range contraction for A. acuminata may be even more pronounced than predicted by our models.

Abies religiosa is an endemic conifer of Mexico, where its monodominant forests are the winter refuge of the monarch butterfly. Due to climate change, it has been estimated that by 2090, A. religiosa populations will decline by 96.5 %. To achieve success, reforestation programs should consider its ectomycorrhizal (ECM) fungi. We used ITS nrDNA sequences to identify the ECM fungi associated with A. religiosa and, based on its abundance and frequency, determined the diversity and community structure in a pure A. religiosa forest near Mexico City. Using sequence metadata, we inferred the species geographic distribution and host preferences. We conducted phylogenetic analyses of the Clavulinaceae (the most important family). The ECM community held 83 species, among which the richest genera were Inocybe (21 species), Tomentella (10 species), and Russula (8 species). Besides its low species richness, the Clavulina-Membranomyces lineage was the most dominant family. Clavulina cf. cinerea and Membranomyces sp. exhibited the highest relative abundance and relative frequency values. Phylogenetic analyses placed the Clavulinaceae genotypes in three different clades: one within Membranomyces and two within Clavulina. A meta-analysis showed that the majority of the ECM fungi (45.78 %) associated with A. religiosa in Mexico have also been sequenced from North America and are shared by Pinaceae and Fagaceae. In contrast, because they have not been sequenced previously, 32.2 % of the species have a restricted distribution. Here, we highlight the emerging pattern that the Clavulina-Membranomyces lineage is dominant in several ECM communities in the Neotropics, including Aldinia and Dicymbe legume tropical forests in the Guyana Shield, the Alnus acuminata subtropical communities, and the A. religiosa temperate forests in Mexico.

Stomatal conductance is considered as a key plant response because it plays an important role in plant physiology by controlling transpiration (water status) and CO2 assimilation, regulating plant productivity. As stomatal conductance is affected by micro-environmental and physiological variables, changes in an altitudinal gradient will have a direct effect on stomatal conductance, which can explain their ecophysiological responses. In this work we used the envelope function method to assess the effect of three climate variables (air temperature, vapor pressure difference, photosynthetically active radiation), and two physiological (leaf water potential, transpiration) on the stomatal conductance response of four tree species ( Alnus acuminata , Quercus xalapensis , Liquidambar styraciflua and Pinus ayacahuite ) from the central mountain region of Veracruz, Mexico. We found that all variables influenced stomatal conductance. We also found differential stomatal conductance responses among species, where A. acuminata had the highest stomatal conductance. We also estimated the optimal temperature when the highest stomatal conductanceoccurs, and among the species, optimal temperaturevaried from 26 to 29 ºC. The most sensitive species to changes in photosynthetically active radiation, leaf water potential and transpiration was L. styraciflua , and for vapor pressure difference was A. acuminata. We also proposed that the stomatal conductance response could help to explain ecophysiological responses along the elevation gradient.

In September 2007, rhizomorphs with morphological characteristics of Armillaria were collected from woody hosts in forests of Mexico State, Veracruz, and Oaxaca, Mexico. Based on pairing tests, isolates were assigned to five somatically compatible genets or clones (MEX7R, MEX11R, MEX23R, MEX28R, and MEX30R). These genets were all identified as Armillaria gallica based on somatic pairing tests against known tester isolates and nucleotide sequences of the translation elongation factor 1α (tef-1α; GenBank Accession Nos. KF156772 to 76). Sequences of tef-1α for all genets showed a max identity of 97 to 99% to A. gallica (ST23, JF313125) (3,4). However, A. gallica comprises a genetically diverse complex that likely represents multiple cryptic species (3). In Mexico, this species has been previously reported in northeastern Morelos on Quercus sp., eastern Mexico State on Pinus hartwegii, and southwestern Mexico State on Prunus persica (1,2). This study identified associations with 10 new hosts within three states of Mexico, but only five hosts were diseased. Genet MEX7R comprised seven isolates collected in the University of Chapingo forest near Texcoco, Mexico State (19°18′10.764″ N, 98°42′14.147″ W, elevation 3441 m). Four MEX7R isolates were collected from diseased Alnus sp. including the root ball of a 130 cm dbh, root-disease killed tree, one isolate from a symptomless Senecio sp. s.l. (Roldana sp.) shrub and two isolates from symptomless Abies religiosa. Genet MEX11R comprised four isolates from a cloud forest near Xalapa, Veracruz (19°31′14.628″ N, 96°59′22.812″ W, elevation 1496 m). MEX11R isolates were collected from the roots of a root-disease killed Carpinus caroliniana, and from trees with no obvious symptoms (Miconia mexicana, Quercus xalapensis, and Liquidambar styraciflua). Two isolates of genet MEX23R were collected from the Jardin Botanico Francisco Javier Clavijero, Instituto de Ecologia, A.C., Xalapa, Veracruz (19°30′49.067″ N, 96°56′32.999″ W, elevation 1344 m). These isolates were from root-diseased Eriobotrya japonica (non-native fruit tree) that showed obvious symptoms (flaccid, chlorotic, and senescing leaves) and from an adjacent, infected Platanus mexicana that did not show readily observable symptoms. Two collections near Oaxaca, Oaxaca, included a single isolate MEX28R from the root ball of a recently root disease-killed Arbutus xalapensis within a small root disease center at Peña Prieta, in Parque La Cumbre, near Ixtepeji (17°09′42.084″ N, 96°38′15.936″ W, elevation 2853 m) and a single isolate MEX30R from the base of an asymptomatic Alnus acuminata near the El Carrizal fish hatchery 10 km northeast of San Miguel del Valle (17°06′45.036″ N, 96°24′03.743″ W, elevation 2594 m). Armillaria gallica has a circumpolar distribution with an extremely wide host range, and its ecological behavior varies greatly. Continued surveys are needed to better understand the distribution and ecological impacts of this pathogen in relation to Armillaria root disease in Mexico and the potential influences of climate change. Although A. gallica displays diverse ecological behavior, trees infected with A. gallica are less likely to survive the stresses of human activity and a changing climate (4). References: (1) D. Alvarado-Rosales and R. A. Blanchette. Phytopathology 84:1106, 1994. (2) R. D. Elias-Roman et al. For. Pathol. 43:390, 2013. (3) M.-S. Kim et al. Phytopathology 102:S4.63, 2012. (4) B. Marcais and N. Breda. J. Ecol. 94:1214, 2006.

Metals are non-biodegradable pollutants, with high environmental persistence that have great toxic effects for the environment and humans. Lead and chromium can be found in the banks of rivers contaminated by domestic and industrial discharges. A number of plants are able to remove metals from the ground and accumulate them in their inner tissues without producing phytotoxic effects. Alnus acuminata ssp. acuminata is a native tree species that can be found on the banks of the contaminated Bogota River and whose phytoremediation capacity for Pb and Cr is unknown. In the study, tree seedlings were irrigated with water from the upper, middle, and lower basin of the river for 4 months. Metal accumulation was measured in the roots, stem, leaves, and soil, and plant parameters such as height, number of leaves, and chlorophyll percentage were recorded. Pb was mainly accumulated in roots (135 mg/kg from upper basin treatment), whereas Cr was found in stems (71 mg/kg). There were no significant differences between treatment and control for any of the three parameters, meaning no toxicity effects were found. Therefore, A. acuminata ssp. acuminata is suggested as a suitable tree for metal phytoremediation along the banks of polluted rivers. © 2016 American Institute of Chemical Engineers Environ Prog, 35: 942–948, 2016

Two pure Alnus acuminata stands established in a montane forest in central Mexico (Puebla State) were monitored between 2010 and 2013 to confirm and recognize the ectomycorrhizal (EcM) systems of A. acuminata with Lactarius cuspidoaurantiacus and Lactarius herrerae, two recently described species. Through comparison of internal transcribed spacer (ITS) of nuclear ribosomal DNA sequences from basidiomes and ectomycorrhizas sampled in the forest stands, we confirmed their ectomycorrhizal association. The phytobiont was corroborated by comparing ITS sequences obtained from EcM root tips and leaves collected in the study site and from other sequences of A. acuminata available in Genbank. Detailed morphological and anatomical descriptions of the ectomycorrhizal systems are presented and complemented with photographs.

Tropical Andean ecosystems have been identified as very vulnerable to climate change. Changes in climatic conditions, especially drought as envisaged by climate change projections, could affect the establishment of new individuals that are responsible for ensuring the persistence of species and plant communities. The aim was to study the main morpho-functional traits related to water use and drought resistance of native plant species from Ecuadorian ecosystems during imposed drought periods. Seedlings of six native species representative of the Ecuadorian Andes were studied: lower montane evergreen forest (Alnus acuminata and Cedrela montana), montane cloud forest (Podocarpus sprucei and Aegiphila ferruginea) and montane dry shrubland (Schinus molle and Caesalpinia spinosa). Morphological characterisation, a root growth capacity test and stomatal conductance measurements during two controlled drought periods were used to investigate biomass allocation patterns, the root system morphology and gas exchange patterns of species, respectively. The main results indicated that species-specific differences in morpho-functional traits and allocation patterns determined responses to water availability and drought conditions. Low relative growth rate, leaf area ratio and specific leaf area, and high specific root length, were related to drought-resistant species as P. sprucei and C. spinosa. In contrast, a high or moderate relative growth rate, leaf area and root biomass, but low specific root length as in A. ferruginea, S. molle, C. montana, were related to lower resistance to drought conditions. Despite A. acuminata showed high specific root length, it was reported as a species sensitive to drought. Overall, patterns of stomatal conductance, linked to biomass allocation patterns and root system morphology, especially specific root length, seemed to be related to differences in vulnerability to drought in these species. Drought response was independent of species habitats. Unexpectedly, P. sprucei, belonging to montane cloud forest showed higher drought resistance than S. molle, belonging to montane dry shrubland. The Ecuador Government has funded this research through the Prometheus Project of the Ministry of Higher Education, Science, Technology and Innovation (SENESCYT). E. Chirino thanks the Department of Ecology of the University Alicante (Spain) and the Forest Restoration Group of the Mediterranean Center for Environmental Studies (Foundation CEAM, Spain) for the equipment provided to carry out the nursery experiments. A. Vilagrosa participation was funded by Projects SURVIVE-2 (CGL2015-69773-C2-2-P) funded by the Spanish Government and DESESTRES (GV-2014-038, Prometeo program, Generalitat Valenciana). S. Ruiz-Yanetti is grateful for the ECOBAL Project (CGL2011-30531-C02-01), Project “Fortalecimiento institucional y transferencia de conocimiento a la ESPOCH (Ecuador) en materia de Servicios Ecosistémicos”, funded by the University of Alicante (Spain), and Programa de Formación de Personal e Intercambio Científico, funded by the Universidad de los Andes (Mérida, Venezuela).

In pure stands of Alnus acuminata subsp. arguta trees from Sierra Norte de Puebla (central Mexico) two undescribed ectomycorrhizal species of Lactarius were discovered. Distinction of the two new species is based on morphological characters and supported with phylogenetic analyses of the nuclear ribosomal DNA ITS region and part of the gene that encodes for the second largest subunit of RNA polymerase II (rpb2). The phylogenies inferred recovered the two species in different clades strongly supported by posterior probabilities and bootstrap values. The new Lactarius species are recognized as part of the assemblage of ectomycorrhizal fungi associated with Alnus acuminata. Information about these taxa includes the morphological variation achieved along 16 monitories 2010-2013. Descriptions are provided. They are accompanied by photos including SEM photomicrographs of basidiospores and information on differences between them and other related taxa from Europe and the United States.

Tropical montane cloud forest has been undergoing a drastic reduction because of its widespread conversion to pastures. Once these forests have been cleared exotic grasses are deliberately introduced for forage production. Exotic grass species commonly form monodominant stands and produce more biomass than native grass species, resulting in the inhibition of secondary succession and tree regeneration. The purpose of this study was to assess the effect of native vs. exotic grass species on the early establishment of two native tree seedlings (Mexican alder, Alnus acuminata and Jalapa oak, Quercus xalapensis) on an abandoned farm in central Veracruz, Mexico. Seedling survival and growth were monitored (over 46 weeks) in relation to grass cover and height, and available photosynthetic active radiation (PAR). More seedlings survived in the presence of the native grass Panicum glutinosum than those growing with the exotic grass Cynodon plectostachyus (92% vs. 48%). The causes of seedling mortality varied between species; Q. xalapensis was affected by herbivory by voles but mainly in the exotic grass-dominated stands, whereas A. acuminata seedlings died due to competition with the exotic grass. A. acuminata seedlings increased more in height in the exotic grass-dominated stands (102 ± 7.8 cm) compared to native grass-dominated stands (51 ± 4.7 cm). Grass layer height, cover and available PAR were correlated (Pearson; p < 0.05). In the exotic grass dominated plots, grass layer height was correlated with the relative height growth rates of Q. xalapensis (Pearson; p < 0.05). These results indicate that the exotic grass may be affecting tree regeneration directly (grass competition) and indirectly (higher herbivory). Passive restoration may occur once P. glutinosum dominated pastures are abandoned. However, when C. plectostachyus dominates, introduction of early and mid successional tree seedlings protected against vole damage is needed.

The arbuscular mycorrhizal fungal (AMF) communities from the Yungas forests of Argentina were studied. The AMF species present in the rhizosphere of some dominant native plants (one tree: Alnus acuminata; three herbaceous species: Duchesnea indica, Oxalis conorrhiza, Trifolium aff. repens; and one shrub: Sambucus peruviana) from two sites (Quebrada del Portugue´s and Narvaéz Range) of the Yungas forests were isolated, identified and quantified during the four seasons of the year. Twenty-two AMF morphotaxa were found. Spore density of some AMF species at each site varied among seasons. The genera that most contributed to the biodiversity index were Acaulospora for Quebrada del Portugue´s and Glomus for Narvaéz Range. High diversity values were observed in the Yungas forests, particularly in the spring (rainy season). We concluded AMF differed in species composition and seasonal sporulation dynamics in the Yungas forests. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina; Argentina Fil: Cabello, Marta. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina Fil: Bartoloni, Norberto. Universidad de Buenos Aires. Facultad de Agronomia; Argentina

In this study we investigated the capacity of Andean alder (Alnus acuminate Kunth), inoculated withFrankia and two ectomycorrhizal fungi (Alpova austroalnicola Dominguez andAlpova diplophloeus ([Zeller and Dodge] Trappe and Smith), for nodulation and growth in pots of a soilless medium that contained vermiculite or a mixture of ground basalt rock and vermiculite. The seedlings were inoculated withFrankia suspensions prepared from root nodules ofA. Acuminate, followed by inoculation with spores of either one of the twoAlpova species. The seedlings were grown in a greenhouse for 12 months. The seedlings grown in the vermiculite-based growth medium containing large (1-3 mm) basalt particles andAlpova austroalnicola or medium-sized (0.5-1 mm) basalt particles andA. Diplophloeus had the heaviest shoot and root nodule dry weights and abundant ectomycorrhizal colonization. Ectomycorrhizas formed byA. Acuminate withAlpova austroalnicola is described here for the first time. Growth ofAlnus acuminate inoculated with ectomycorrhizal fungi andFrankia in the soilless primary minerals indicates that Andean alder can alter resource supply by tapping an otherwise unavailable nutrient source. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Menoyo, Eugenia. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lett, Irene. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Li, Ching Y.. Forestry Sciences Laboratory; Estados Unidos

A list with the names of miscellaneous botanical collections made by the authors in San Damian district (Huarochiri province, Lima department), in Central Peru, is provided. Most reported species are rosids, and will be thoroughly treated later. We report more than fifty records for the general flora of the place, including asterids, rosids, grasses and lichens. The present work is a support document for the License thesis of the first author, where further explanations and insights are to be provided. PeerJ PrePrints | https://dx.doi.org/10.7287/peerj.preprints.1523v1 | CC-BY 4.0 Open Access | rec: 24 Nov 2015, publ: 24 Nov 2015 Introduction San Damian district is located at 18 L 351228 8669394 (UTM) (12,0333o SL, 76,3667o WL), in the province of Huarochiri, Lima department (IGN, 2013). It houses a rich, however perturbated, flora. Here, we present miscellaneous collections made by the three first authors during the years 2013 and 2014. Vouchers are deposited in “Augusto Weberbauer” Herbarium (MOL), where identification of the specimens took place. Additional specimens were confirmed by the senior author with the help of the latter three authors in the “San Marcos” Herbarium (USM). Checklist of botanical species Nomenclatural information taken from Tropicos (2015). ALSTROEMERIACEAE Dumort. Bomarea ovata (Cav.) Mirb. ASTERACEAE Bercht. & J. Presl Aristeguietia discolor (DC.) R.M. King & H. Rob. Cotula australis (Sieber ex Spreng.) Hook. f. Gnaphalium dombeyanum DC. Heliopsis buphthalmoides (Jacq.) Dunal Lomanthus subcandidus (A. Gray) B. Nord. Matricaria chamomilla L. Mutisia acuminata Ruiz & Pav. Paracalia jungioides (Hook. & Arn.) Cuatrec. Senecio richii A. Gray Smallanthus parviceps (S.F. Blake) H. Rob. Tagetes multiflora Kunth Tanacetum parthenium (L.) Sch. Bip. Villanova oppositifolia Lag. BETULACEAE Gray Alnus acuminata Kunth (Betulaceae) BRASSICACEAE Burnett Brassica rapa L. Capsella bursa-pastoris (L.) Medik Cardamine bonariensis Juss. ex Pers. Descurainia myriophylla (Willd. ex DC.) R.E. Fr. Lepidium bipinnatifidum Desv. Nasturtium officinale W.T. Aiton Sisymbrium erysimoides Desf. Sisymbrium orientale L. CUCURBITACEAE Juss. Sicyos baderoa Hook. & Arn. EUPHORBIACEAE Juss. Euphorbia peplus L. PeerJ PrePrints | https://dx.doi.org/10.7287/peerj.preprints.1523v1 | CC-BY 4.0 Open Access | rec: 24 Nov 2015, publ: 24 Nov 2015 FABACEAE Lindl. Lupinus ballianus C.P. Sm. Lupinus mutabilis Sweet Medicago lupulina L. Medicago polymorpha L. Medicago sativa L. Spartium junceum L. Trifolium repens L. Trifolium peruvianum Vogel Vicia andicola Kunth Vicia faba L. GERANIACEAE Juss. Erodium cicutarium (L.) L'Her. ex Aiton Erodium malacoides (L.) L'Her. ex Aiton Erodium moschatum (L.) L'Her. ex Aiton Geranium core-core Steud. Geranium sessiliflorum Cav. Geranium smithianum R. Knuth GROSSULARIACEAE DC. Ribes viscosum Ruiz & Pav. MALVACEAE Juss. Fuertesimalva echinata (L.) Fryxell Fuertesimalva peruviana (L.) Fryxell Malva parviflora L. MYRTACEAE Juss. Eucalyptus camaldulensis Dehnh. Eucalyptus globulus Labill. ONAGRACEAE Juss. Fuchsia denticulata Ruiz & Pav. Oenothera rosea L'Her. ex Aiton Oenothera sandiana Hassk. OXALIDACEAE R. Br. Oxalis megalorrhiza Jacq. Oxalis corniculata L. PARMELIACEAE Zenker Everniopsis trulla (Ach.) Nyl. PASSIFLORACEAE Juss. ex Roussel Passiflora peduncularis Cav. Passiflora tripartita (Juss.) Poir.

Literature reports both positive and negative effects of N-fixing alders on conifer growth in alder-conifer stands. Such divergent effects probably result from poorly understood species interactions. The aim of this work was to examine how varying alder-to-pine ratios (APRs) and N fertilization affect pine nutrient status. A pseudo-experiment was installed in each of two areas of regeneration (AR) with different amounts of radiation reaching alder. The experimental approach consisted of a series of pseudoreplicated plots with five APRs within each AR. Half of each plot received 200 kg N ha–1. Data were interpreted by vector analysis. Alders in the AR 1987 induced needle-biomass reductions, K deficiency, and P accumulation in pine needles. However, nutrient availability increased with the proportion of alders in the AR 1989, where alders received high sunlight due to a less dense pine stand. Nitrogen fertilization increased needle biomass and N in three out of five alder proportions where alders were sunlight-limited. In the other stand, with the exception of the no-alder and A4 plots, positive effects of N fertilization increased with decreasing alder density. We conclude that sunlight-limited alders may not positively affect associated-species growth even in N-limited sites.

Ectomycorrhizae (ECM) of Lactarius aff. omphaliformis Romagn., Russula alnijorullensis (Sing.) Sing. and Cortinarius tucumanensis Mos. on Andean alder (Alnus acuminata Kunth) were characterized and identified. The identification of the fungal symbionts was achieved by morpho-anatomical observations of mycorrhizae and by comparison of ITS-RFLP patterns obtained from ECM and fruitbodies. L. aff. omphaliformis ECM differed in some morphological details such as ramification and mantle type from ECM of the same species on A. glutinosa. L. aff. omphaliformis ECM show an orange to ochre mantle containing latex cells, which stain with sulpho-vanillin, emanating hyphae without clamps. R. alnijorullensis ECM represent a typical Russula-type-ECM, light yellow to pinkish, the outer mantle being composed of triangular latex-filled cells staining with sulpho-vanillin, emanating hyphae without clamps. C. tucumanensis ECM exhibit a white (silvery) to yellowish brown mantle covered with soil particles, emanating hyphae with clamps. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Beenken, Ludwig. Ludwig Maximilians Universitat; Alemania Fil: Pritsch, Karin. Technische Universitat Munchen; Alemania Fil: Daniele, Graciela María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Schloter, Michael. National Research Centre for Environment and Health; Alemania Fil: Agerer, Reinhard. Ludwig Maximilians Universitat; Alemania

Fil: Nouhra, Eduardo Ramon. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto Multidisciplinario de Biologia Vegetal. Universidad Nacional de Cordoba. Facultad de Ciencias Exactas Fisicas y Naturales. Instituto Multidisciplinario de Biologia Vegetal; Argentina

A procedure for in vitro plant regeneration of Alnus acuminata from epicotyls with cotyledonary buds was developed using different media formulations with different growth regulators and carbon sources. The development of multiple buds on explants at the initiation step was obtained with MS at 1/2 strength with either 1 or 2 μM of BAP but not without it. Multiplication gave up to 15 elongating shoots by explant, the best medium being MS supplemented with vitamins from B5 medium, 1 μM of BAP and 87 mM sucrose. Rooting of about 88% occurred in the medium MS with 83 mM sucrose and 1 μM IBA. Alnus acuminata did not developed well on WPM. Roots of in vitro propagated plants were nodulated by Alnus-infective Frankia. The root nodules show a typical alder root nodule anatomy and differentiation pattern and effectively fixed nitrogen. Rhamnaceae-infective Frankia did not nodulate in vitro cultivated Alnus acuminata suggesting that symbiotic recognition was not altered by in vitro regeneration of the plant. Fil: Enrico, Roxana Judith. Universidad Nacional de Quilmes; Argentina Fil: Ramírez, Silvia Patricia. Universidad Nacional de Quilmes; Argentina Fil: Mroginski, Luis Amado. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; Argentina Fil: Wall, Luis Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; Argentina

Field ectomycorrhizae of Naucoria escharoides on Alnus acuminata ("andean alder", "aliso del cerro") are described in detail for the first time. Naturally occurring ectomycorrhizal roots were sampled beneath sporocarps of N. escharoides. The samples were taken from four natural forest plots at two homogeneous A. acuminata sites (Tucumán and Catamarca Provinces, Argentina). The ectomycorrhizae were characterized morphologically and compared by means of PCR/RFLP analysis of the internal transcribed spacer region of the nuclear rDNA. The most important morphological features of the ectomycorrhizae are a white to pale yellow mantle, simple to monopodial branches, hyaline emanating hyphae, abundant hyphal bundles emerging more or less perpendicularly from a plectenchymatous mantle, and an acute or rounded apex with or without a mantle. N. escharoides fruitbodies have white basal mycelium with emanating hyphae similar to those of andean alder ectomycorrhizae. The RFLP profiles of sporocarps and mycorrhizae were the same. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Daniele, Graciela María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Dominguez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Nouhra, Eduardo Ramon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. State University of Oregon; Estados Unidos Fil: Horton, Tom. University of Oregon; Estados Unidos

Ectomycorrhizal (ECM) fungal associates of Alnus are relatively few in comparison with those associated with other tree hosts. The composition of ECM assemblages associated with Alnus seems to change very little across the Northern Hemisphere. However, Alnus-associated ECM assemblages from the Western United States, Mexico, and Argentina tend to differ from those in eastern North America and Europe, presumably due to their different biogeographic histories. Alnus glutinosa is a northern European species subjected to diverse environmental conditions. To address intrageneric host preference within two distantly related Alnus species (Alnus acuminata and A. glutinosa), we tested the ECM colonization on seedlings of both species inoculated with natural soil from A. acuminata forests. Two tomentelloid ECM fungi from A. acuminata natural soils were determined from the anatomotyping and molecular analysis. Both species colonized A. glutinosa seedlings and presented similar relative abundances. Additional soil sequence data from A. acuminata sites suggest that a variety of tomentelloid taxa occur, including several unidentified Tomentella lineages. Maximum-likelihood and Bayesian inference analyses based on internal transcribed spacer (ITS) sequences from various locations do not reflect associations of taxa based on their biogeographic origin, and clades are in general constituted by sequences from diverse regions, including South America, Mexico, USA, and Europe. Results illustrate the probable role of specific tomentelloid fungi in the early colonization of seedlings in A. acuminata forests as well as their importance in the structure of the ECM propagule community at the sites. Fil: Nouhra, Eduardo Ramon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Pastor, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Sarrionandia Areitio, Estibaliz. Universidad del País Vasco; España Fil: Geml, Jozsef. Leiden University; Países Bajos

The tree species Alnus acuminata and Morella pubescens, native to South America, are candidates for soil quality improvement and afforestation of degraded areas and may serve as nurse trees for later inter-planting of other trees, including native crop trees. Both species not only form symbioses with arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF), but also with N2-fixing actinobacteria. Because tree seedlings inoculated with appropriate mycorrhizal fungi in the nursery resist transplanting stress better than non-mycorrhizal seedlings, we evaluated for A. acuminata and M. pubescens the potential of inoculation with mycorrhizal fungi for obtaining robust tree seedlings. For the first time, a laboratory-produced mixed AMF inoculum was tested in comparison with native soil from stands of both tree species, which contains AMF and EMF. Seedlings of both tree species reacted positively to both types of inocula and showed an increase in height, root collar diameter and above- and belowground biomass production, although mycorrhizal root colonization was rather low in M. pubescens. After 6 months, biomass was significantly higher for all mycorrhizal treatments when compared to control treatments, whereas aboveground biomass was approximately doubled for most treatments. To test whether mycorrhiza formation positively influences plant performance under reduced water supply the experiment was conducted under two irrigation regimes. There was no strong response to different levels of watering. Overall, application of native soil inoculum improved growth most. It contained sufficient AMF propagules but potentially also other soil microorganisms that synergistically enhance plant growth performance. However, the AMF inoculum pot-produced under controlled conditions was an efficient alternative for better management of A. acuminata and M. pubescens in the nursery, which in the future may be combined with defined EMF and Frankia inocula for improved management practices.

The main objective of this study consisted of evaluating the fodder potential of the foliage of Buddleia cordata, Montanoa leucantha subsp. arborescens, Erythrina chiapasana, Quercus rugosa and Alnus acuminata var. arguta, tree species present in The Highlands of Chiapas, Mexico, in order to select the best fodder and carry out an evaluation of the species with greatest potential in sheep feeding. The chemical composition results on a dry matter basis were as follows: the crude protein (CP) content ranged from 8.4% in Q. rugosa to 27.7% in M. leucantha. Neutral detergent fiber (NDF) ranged from 39.0% in M. leucantha to 58.3% in Q. rugosa and Acid detergent fiber (ADF) varied from 30.8% in M. leucantha to 56.8% in Q. rugosa; Gross energy (GE) contents were 3.0 kcal/g or even greater. Tannic acid was detected from 0.25 g/100 g in E. chiapasana to 1.1 g/100 g in Q. rugosa; there were no cyanogenic glucosides detected in the samples, and no alkaloids were encountered in Q. rugosa and A. acuminata, but E. chiapasana showed higher alkaloid content than the other trees. Q. rugosa had the highest foliage production (6.9 kg DM/plant/cut), while E. chiapasana had the lowest production (1.2 kg DM/plant/cut). In an in vivo intake and digestibility trial, the leaves of M. leucantha fed as a sole diet for sheep had the best composition values, higher (P 0.05) in diets including 0%, 25% and 40% of Montanoa leucantha leaves.

Se presentan los resultados del estudio anatómico de la madera de Alnus acuminata Kunth, Ostrya virginiana Rose, Quercus dysophylla Benth., Quercus glabrescens Benth., Arbutus glandulosa DC., Arbutus tessellata Sorensen, Styrax argenteus Presl. y Buddleia wrightii Robinson, de muestras provenientes de los estados de Jalisco y Puebla. Para cada taxa estudiado, se describe n los caracteres anatómicos de los vasos, parénquima axial , radios y fibras; también se sugieren algunos usos para la madera de estas especies.

The objective of this study was to describe the morphological and anatomical features of five unidentified ectomycorrhizal types of Alnus acuminata and to complement their identification based on ITS-rDNA sequence analysis. The combined approach of morphotyping and sequence analysis based on ITS sequence comparison with sequences contained in GenBank and the UNITE database let us assign three of the five field-collected ectomycorrhiza morphotypes to the tomentella-thelephora lineage that closely matched European and North American species. The sequencing results within Tomentella point toward alder specific clades within T. sublilacina, T. ellisii and T. stuposa sensu lato. The two other EcM morphotypes matched Lactarius omphaliiformis and a Russula sp. Better focused, concomitant fruit body surveys are needed for accurate identification of South American ectomycorrhizal fungi because of the evidence of cryptic speciation in both agaricoid and resupinate mycobionts.

Se estudió el efecto de la adición de B en Andisoles sobre las variables altura, diámetro y volumen de los árboles en 5 plantaciones de Alnus acuminata de edad inicial en años de 0,5 en Hermanas Callejas (HC), 1 en Lechería Experimental (LE), 3 en Rosa Marta Cubero (RMC), 5 en Landelina (L) y 7 en Carter (C); a la última evaluación, las plantaciones tenían 3 años más de edad. El B se suplió como Boronato y se aplicó al voleo en cantidades de 0, 2, 4, 6 y 8 kg.ha-1 para determinar su efecto residual a los 14 meses después de aplicado. El B adicionado incrementó su disponibilidad en el suelo, incremento que puede detectarse mediante extracción con agua caliente presurizada o con Mehlich 3. Los valores de correlación entre el B aplicado y el B extraído por el método de Mehlich 3 son mejores que los obtenidos con el método de agua caliente presurizada. La incorporación de 0 a 8 kg.ha-1 del elemento, no causó ningún incremento en las variables dasométricas del jaúl en los sitios comparados, excepto por un incremento significativo en volumen de madera en la plantación de Landelina (8 años de edad). La poca o ninguna respuesta encontrada, se atribuye a que el contenido inicial de B disponible en el suelo osciló entre 0,19-1,00 mg.kg-1, valores en su mayoría sobre el valor crítico de 0,5 mg.kg-1 mencionado para cultivos en Andisoles y a un bajo requerimiento de B por parte del jaúl. La concentración foliar de B tendió a aumentar ligeramente conforme se elevó la cantidad de B adicionada al suelo, mientras que la concentración de N foliar no mostró ninguna tendencia. Abstract Soil boron extraction methods and alder response to boron additions in Andisols of Costa Rica. The effect of B to Andisols on tree height, diameter and volume of 5 Alnus acuminata plantations was studied. Plantation initial ages in years were: 0.5 at Hermanas Callejas (HC), 1 at Lechería Experimental (LE), 3 at Rosa Marta Cubero (RMC), 5 at Landelina (L) and 7 at Carter (C); at the end of the experiment plantations were 3 years older. B was supplied as Boronate and broadcasted at rates of 0, 2, 4, 6 and 8 kg.ha-1; the residual effect of fertilizer was determined 14 months after its application. The fertilizer added incremented B availability in the soils, as measured with pressurized hot water and Mehlich 3 methods. R² values obtained were higher with correlations obtained by the Mehlich 3 procedure. The B applied did not cause increments of dasometric variables measured, except for a significant increase in volume of wood at Landelina (8 year old plantation). The lack of response in growth variables to B addition are attributed to the initial B availability in the soils (0.19-1.00 mg.kg-1), most values above the critical value of 0.5 mg.kg-1 mentioned for crops in Andisols, and the low requirement of B in alder. Foliar concentration of B showed a slight tendency to increase with growing amounts of B applied to the soil, while N foliar concentration did not show any tendency after B addition to the soil.

Integration of trees on farms may exert complementary or competitive effects on crop yield. This 4 year study examined novel systems in which Alnus acuminata (alnus), Calliandra calothyrsus (calliandra), Sesbania sesban (sesbania) or a mixture of all three were grown on the degraded upper part of bench terraces in Uganda; beans or maize were grown on the more fertile lower terrace during the short and long rains. Three pruning treatments (shoot, root or shoot + root pruning) were applied to the tree rows adjacent to the crops; shoot prunings were applied as green manure to the woodlot from which they came. Pruning increased survival in calliandra and reduced survival in sesbania; alnus was unaffected. Pruning reduced tree height and stem diameter in alnus, but did not affect calliandra or sesbania. Maize yield adjacent to unpruned calliandra, alnus and sesbania or a mixture of all three was reduced by 48, 17, 6 and 24% relative to sole maize. Shoot pruning initially sustained crop performance but shoot + root pruning became necessary when tree age exceeded 2 years; shoot + root pruning increased maize yield by 88, 40, 11 and 31% in the calliandra, alnus, sesbania and tree mixture systems relative to unpruned trees. Bean yield adjacent to unpruned calliandra, alnus, sesbania and the tree mixture was 44, 31, 33 and 22% lower than in sole crops and pruning had no significant effect on crop yield. The results suggest that sesbania fallows may be used on the upper terrace without reducing crop yield on the lower terrace, whereas pruning of alnus is needed to sustain yield. Calliandra woodlots appear to be unsuitable as crop yield was reduced even after pruning.

In Argentina the Yungas forests are among the ecosystems most affected by human activity, with loss of biodiversity. To assess the arbuscular mycorrhizal (AM) colonization and the arbuscular mycorrhizal fungi (AMF) spore numbers in these ecosystems, the roots of the most dominant native plants (one tree, Alnus acuminata; three herbaceous, Duchesnea indica, Oxalis conorrhiza, Trifolium aff. repens; and one shrub, Sambucus peruviana) were studied throughout the year from two sites of Yungas forests. Assessments of mycorrhizal colonization (percent root length, intraradical structures) were made by washing and staining the roots. Soil samples of each plant species were pooled and subsamples were obtained to determine AM spore numbers. The herbaceous species formed both Arum- and Paris-type morphologies, whereas the tree and the shrub species formed respectively single structural types of Arum-and Paris-type. AM colonization, intraradical fungi structures and AMF spore numbers displayed variation in species, seasons and sites. D. indica showed the highest AM colonization, whereas the highest spore numbers was observed in the rhizosphere of A. acuminata. No correlation was observed between spore numbers and root length percentage colonized by AM fungi. Results of this study showed that Alnus acuminata is facultatively AM. The AM colonization, intraradical fungi structures and AMF spore numbers varied in species depending on phenological, climatic and edaphic conditions., Instituto de Botánica "Dr. Carlos Spegazzini"

Trials of a common set of seed lots representing 39 parents and five species of Alnus have been started in four countries: Belgium, Canada, the UK, and the U.S. Initial results indicate that cold hardiness is a problem in using A. acuminata but that sufficiently hardy A. rubra sources are available. A. glutinosa had the best growth in the nursery, and A. cordata had the best survival under severe moisture-stress conditions. A summary also is given of a workshop on alder improvement that further demonstrates the potential for developing the genus for biomass energy production.

In Argentina, the Yungas forests are among the ecosystems most affected by human activity, with loss of biodiversity. To assess the mycorrhizal status in these ecosystems, the roots of 41 native plant species belonging to 25 families were collected throughout the year from two sites of the Yungas forests. Roots were washed and stained to study the presence of arbuscular mycorrhizas (AM). Morphological types of arbuscular mycorrhizas (Arum and Paris-type) and colonization patterns were identified and photographed. All plants presented AM colonization. The AM colonization patterns varied from single intracellular aseptate hyphae, coils, appresoria, to vesicles and/or arbuscules. Among the species studied, the Paris-type colonization showed to be dominant. Results confirmed that AM hosts are predominant in the Yungas of South American forests. © INRA, EDP Sciences, 2007. En Argentine, les Yungas constituent un des écosystèmes les plus atteints par l’activité de l’homme, avec la perte de biodiversité qui en découle. Pour évaluer le statut mycorhizien de ces écosystèmes, les racines de 41 plantes autochtones appartenant à 25 familles ont été collectées au cours de l’année dans deux sites des forêts des Yungas. Les racines ont été lavées et teintes afin de déterminer la présence des mycorhizes arbusculaires (MA). Les types morphologiques de MA (type Arum et Paris) et les patrons de colonisation ont été identifiés et photographiés. Toutes les plantes ont présenté une colonisation MA. Les structures fongiques intraracinaires comprenaient des hyphes intracellulaires sans cloison, des boucles, des appressoria, des vésicules et/ou des arbuscules. Le type de colonisation Paris est apparu comme dominant parmi les espèces étudiées. Les résultats confirment que les hôtes avec MA prédominent dans les forêts sudaméricaines des Yungas. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Cabello, Marta Noemí. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Chiarini, Franco Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina

The objective of this study was to determine patterns of ECM colonization of Andean alder at two natural forests in relation to soil parameters at two different seasons (autumn and spring). The soil parameters studied were field capacity, pH, electrical conductivity, available P, total N and organic matter. Twelve ECM morphotypes were found on A. acuminata roots. The ECM colonization varied among soil types and was affected positively by electrical conductivity. Multiple regression relationships among ECM colonization and edaphic properties variables showed no significant differences at two seasons and among soil types with respect to morphotype diversity values. Positive correlations were found between three morphotypes (Cortinarius tucumanensis, Gyrodon monticola and Russula alnijorrulensis) and soil types and two other morphotypes (Naucoria escharoides and Lactarius sp.) between two seasons. Results of this study provide evidence that ECM colonization of A. acuminata is affected by some chemical edaphic parameters and indicate that some ECM morphotypes are sensitive to changes in seasonality and soil parameters., Colonisation ectomycorrhizienne d'Alnus acuminata Kunth au nord-ouest de l'Argentine en relation avec la saison et quelques paramètres du sol. Le but de cette étude était de déterminer, au cours de deux différentes saisons (août et printemps), les modèles de colonisation de l'aulne andin dans deux forêts naturelles en relation avec quelques paramètres de sol. Les paramètres de sol étudiés étaient la capacité au champ, le pH, la conductivité électrique, le P disponible, le N total et la matière organique. Douze morphotypes de ECM ont été trouvés sur des racines de A. acuminata. La colonisation par les ECM varie en fonction des types de sols et est affectée positivement par la conductivité électrique. Les relations de régression multiple entre la colonisation de ECM et les variables de propriétés du sol n'ont montré aucune différence significative entre les deux saisons et entre les types de sol pour ce qui concerne des valeurs de diversité morphotypique. Des corrélations positives existent entre Cortinarius tucumanensis, Gyrodon monticola et Russula alnijorrulensis et les types de sol, et entre Naucoria escharoides et Lactarius sp. et les deux saisons. Les résultats de cette étude mettent en évidence que la colonisation de ECM de A. acuminata est affectée par quelques paramètres édaphiques chimiques et indiquent que quelques morphotypes de ECM sont sensibles aux changements des paramètres saisonniers et pédologiques.

Field studies in Argentina’s Yunga District revealed Alpova austroalnicola sp. nov., a hypogeous fungus associated with Alnus acuminata ssp. acuminata. Morphological and molecular studies based on amplification and sequencing of the nuclear LSU rDNA gene showed its unique identity within Alpova. Related genera included in the analyses were Boletus edulis, Rhizopogon spp., Suillus luteus and Truncocolumella citrina. Additional observations of animal diggings around the sites and microscopic examination of fecal pellets of the nine-banded armadillo (Dasypus novemcinctus novemcinctus) indicate A. austroalnicola is consumed and its spores dispersed by animals. Key words: Alnus acuminata, Boletales, Dasypus, molecular systematics, mycophagy, phylogeny Fil: Nouhra, Eduardo Ramon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Dominguez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Trappe, James M.. State University of Oregon; Estados Unidos

The objective of this study was to determine patterns of ectomycorrhizas (ECM) and arbuscular mycorrhizas (AM) colonization associated with Alnus acuminata (Andean alder), in relation to soil parameters (electrical conductivity, field H2O holding capacity, pH, available P, organic matter, and total N) at two different seasons (autumn and spring). The study was conducted in natural forests of A. acuminata situated in Calilegua National Park (Jujuy, Argentina). Nine ECM morphotypes were found on A. acuminata roots. The ECM colonization was affected by seasonality and associated positively with field H2O holding capacity, pH, and total N and negatively associated with organic matter. Two morphotypes (Russula alnijorullensis and Tomentella sp. 3) showed significant differences between seasons. Positive and negative correlations were found between five morphotypes (Alnirhiza silkacea, Lactarius omphaliformis, Tomentella sp. 1, Tomentella sp. 3, and Lactarius sp.) and soil parameters (total N, pH, and P). A significant negative correlation was found between field H2O holding capacity and organic matter with AM colonization. Results of this study provide evidence that ECM and AM colonization of A. acuminata can be affected by some soil chemical edaphic parameters and indicate that some ECM morphotypes are sensitive to changes in seasonality and soil parameters. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Zak, Marcelo Román. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. Universidad Empresarial Siglo XXI; Argentina Fil: Horton, Thomas R.. College of Environmental Science and Forestry; Estados Unidos Fil: Micolini, Jorge. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina

Field ectomycorrhizas of Cortinarius helodes Moser, Matheny & Daniele (sp. nov) and Gyrodon monticola Sing. on Alnus acuminata Kunth (Andean alder, aliso del cerro) are described based on morphological and anatomical features. Ectomycorrhizal roots were sampled beneath fruitbodies of C. helodes and G. monticola from two homogeneous A. acuminata forest sites located in Tucumán and Catamarca Provinces in Argentina. C. helodes ectomycorrhizas showed a thick white to beige mantle exuding a milky juice when injured, were bluish toward the apex, and had hyphal strands in the mantle. G. monticola ectomycorrhizas showed some conspicuous features like highly differentiated rhizomorphs, inflated brown cells on the mantle surface, and hyaline and brown emanating hyphae with dolipores. Restriction fragment length polymorphism analysis of the nuclear rDNA internal transcribed spacer provided a distinctive profile for each of the collections of fruitbodies and the mycorrhizal morphotypes. Fil: Becerra, Alejandra Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Nouhra, Eduardo Ramon. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina. State University of Oregon; Estados Unidos Fil: Daniele, Graciela María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: Dominguez, Laura Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentina Fil: McKay, Donaraye. USDA Forest Service; Estados Unidos

It is a dictum that Apis mellifera Linnaeus is innocuous in agricultural ecosystems. This study provides the first record of A. mellifera as a significant defoliator of Alnus species. Careful field observations coupled with microscopic examination provided convincing evidence implicating A. mellifera as the cause of leaf perforation on Alnus species in Uganda. Apis mellifera was observed foraging selectively on young Alnus leaves and buds in search of a sticky substance, apparently propolis. In so doing, the bee created wounds that enlarged and caused tattering of Alnus leaves as they matured. Biological surveys indicated that the damage was prevalent and occurred widely, particularly on Alnus acuminata Kunth in Uganda. Incidence of the Apis mellifera damage on Alnus acuminata peaked in the dry season, with up to 90% of leaves emerging per shoot per month damaged, and was lowest in the wet months during peak leaf emergence. Apis mellifera leaf damage was consistently higher on Alnus acuminata than A. nepalensis D. Don., on saplings than mature trees, and on sun exposed than shaded leaves. The activity of honeybees may be detrimental to the productivity of Alnus, yet the substance for which the insect forages on Alnus is a resource with potential economic importance.

Frankia BCU110501 induces nitrogen-fixing root nodules in Discaria trinervis (Gillies ex Hook. & Arn.) Reiche (Rhamnaceae) via intercellular colonisation, without root hair deformation. It produces diffusible factors (DFs) that might be involved in early interactions with the D. trinervis roots, playing a role in the nodulation process. The induction of root nodule development in actinorhizal symbiosis would depend on the concentration of factors produced by the bacteria and the plant. A detailed analysis of nodulation kinetics revealed that these DFs produce changes at the level of initial rate of nodulation and also in nodulation profile. Diluted Frankia BCU110501 inoculum could be activated in less than 96 h by DFs produced by Frankia BCU110501 cells that had been previously washed. Biochemical characterisation showed that Frankia BCU110501 DFs have a molecular weight of

Nodulation kinetics were analysed in two nitrogen-fixing actinorhizal symbioses that show different pathways for infection: Alnus acuminata H. B. K., which is infected by Frankia ArI3, and Discaria trinervis (Hooker et Arnot) Reiche, which is infected by Frankia BCU110501. Both pairs are incompatible in cross-inoculation experiments. The dose–response effects in nodulation were studied in A. acuminata seedlings using different concentrations of compatible and incompatible bacteria in co-inoculation experiments. Restriction fragment length polymorphism PCR analysis and plant-trapping analysis showed no co-occupation in A. acuminata nodules when plants were co-inoculated with Frankia BCU110501 and Frankia ArI3. Despite the lack of co-occupation, the noninfective BCU110501 could modify the nodulation parameters of the non-host A. acuminata when infective ArI3 was present in the inoculum. The results suggest that although BCU110501 was not able to induce nodulation in A. acuminata, its interaction with the plant could induce autoregulation as if some level of infection or partial recognition could be achieved. We explored the possibility that physiological complementation of the heterologous Frankia BCU110501 for nodulation of A. acuminata originated in the homologous Frankia ArI3 in the presence of compatible root exudates. Despite the possibility of full activation between bacteria and the host, there was no co-infection of Frankia BCU110501 in Alnus or of Frankia ArI3 in Discaria either. These negative results suggest a physical recognition barrier in actinorhizal symbiosis that operates after early interactions, involving something other than root exudates and diffusible factors of bacterial or plant origin, regardless of the infection pathway.

The objective of this study was to compare the interaction betweenFrankia and vesicular-arbuscular mycorrhizae (VAM) on the growth and N-fixing response ofAlnus acuminata seedlings under three different phosphorus levels.A. acuminata is an actinorhizal tree, commonly associated with pastures on upland areas. Seedlings were grown in sterile vermiculite, and inoculated withFrankia strain ArI3 and/or VAM (asGlomus intra-radices) under three phosphorus levels (10, 50 and 100 ppm). After 120 days differences in growth were observed at the 50 ppm P level between nodulated and non-nodulated plants; either if inoculated withFrankia+VAM or just with VAM. Interaction betweenFrankia and VAM was positive on nodule weight at 50 ppm P level. Differences in acetylene reduction, per gram of fresh nodule, were observed between and within both groups:Frankia inoculated andFrankia+VAM inoculated seedlings. InFrankia inoculated seedlings differences were observed between seedlings receiving 50 ppm P which showed higher nitrogenase activity than seedlings treated with 100 ppm P. Plants inoculated withFrankia andGlomus intra-radices at low P level (10 ppm) showed the highest acetylene reduction. It was 150% higher than the mean of the other treatments within the group, and 87% higher than the general mean of the onlyFrankia inoculated plants.