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A taxonomic revision of the genus Podagrostis (Griseb.) Scribn. & Merr. is presented, including two new combinations: P. meridensis (Luces) A. M. Molina & Rúgolo and P. novogaliciana (McVaugh) A. M. Molina & Rúgolo. Podagrostis bacillata (Hack.) Sylvester & Soreng constitutes a new report for Colombia. Information regarding synonymy, geographical distribution, habitat, iconography, and vernacular names is provided along with complete illustrations and a list of additional specimens examined. A key for the identification of the species is included as well as a comparative table based on macro- and micromorphological data. The anatomical character of Trichodium net on lemma epidermis, as well as its diagnostic value, is discussed in species of Podagrostis and most related genera (e.g., Agrostis L., Chaetotropis Kunth, and Polypogon Desf., among others).

Rúgolo de Agrasar recognized two varieties of Deyeuxia velutina (D. velutina var. velutina and D. velutina var. nardifolia) based on leaf sheath indumentum, lemma length, and leaf blade direction. However, taxonomic delimitation has been difficult due to occasional overlapping characters. To assess the infraspecific delimitation of D. velutina, we present a comprehensive study combining morphometric analyses and a potential distribution model. To explore morphological variation and select diagnostic characters, we measured 124 morphological characters in 52 specimens of both varieties and performed a principal coordinate analysis and univariate analyses (Analysis of variance and Kruskal-Wallis non-parametric test). Both taxa resolved as separate morphological groups. Additionally, a Discriminant Analysis was performed to classify the individuals in the predetermined morphological groups. For modeling the species distribution, 26 specimens of D. velutina var. nardifolia and 68 of D. velutina var. velutina were georeferenced and 20 environmental variables were analyzed through a Maximum Entropy model. Deyeuxia velutina extends in the high Andean region from Peru to southern Argentina and Chile. Both varieties differed in their geographical limits, a result supported by regression analyses of latitude and longitude on the principal coordinates of the PCoA. Deyeuxia velutina var. nardifolia is restricted to the northern area of distribution while D. velutina var. velutina showed a higher habitat suitability in the southern region. Moreover, D. velutina var. nardifolia is here reported for the first time in San Juan province (Argentina), constituting the austral limit of its geographical distribution. Additional reliable morphological characters were considered in an updated key to the varieties.

Agrostis laegaardii A. M. Molina & Rúgolo (Poaceae), a new species restricted to the high páramos from Colombia and Ecuador, is described and illustrated. It is morphologically most similar to A. breviculmis Hitchc. but differs in spikelet length, pedicel apex, glume texture, relative distance between upper glume and floret, lemma and palea length, and the presence of an awn on the lemma. Micromorphology of the spikelet is discussed, and a Trichodium net is reported on the epidermis of the lemma. A distribution map and a key to the Colombian and Ecuadorean species of Agrostis L. with contracted inflorescences are provided. Fil: Palacio, Patricia Candela. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Molina, Ana M.. Instituto Nacional de Tecnología Agropecuaria; Argentina Fil: Rúgolo, Zulma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Vega, Andrea Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina

A new, narrowly endemic species from the Andean western slopes of central Peru, Chusquea limensis (Poaceae, Bambusoideae, Bambuseae), is described and illustrated. Identification keys and a comparative table based on vegetative and reproductive characters, including morphologically similar species such as C. huantensis, C. inamoena, C. scandens and C. tarmensis, as well as habitat and geographical distribution notes, are included. Additionally, anatomical and micromorphological characters of the culm and foliage leaf blades of the new species are presented, as a valuable tool for the identification of sterile specimens.

Nitrate can act as a potent signal to control growth and development in plants. Here we show nitrate is able to stimulate primary root growth via increased meristem activity and cytokinin signaling. Cytokinin perception and biosynthesis mutants displayed shorter roots as compared to wild type plants when grown with nitrate as the only nitrogen source. Histological analysis of the root tip revealed decreased cell division and elongation in the cytokinin receptor double mutant ahk2/ahk4 as compared to wild-type plants under a sufficient nitrate regime. Interestingly, a nitrate-dependent root growth arrest was observed between days 5 and 6 after sowing. Wild-type plants were able to recover from this growth arrest while cytokinin signaling or biosynthesis mutants were not. Transcriptome analysis revealed significant changes in gene expression after, but not before this transition in contrasting genotypes and nitrate regimes. We identified genes involved in both cell division and elongation as potentially important for primary root growth in response to nitrate. Our results provide evidence linking nitrate and cytokinin signaling for the control of primary root growth in Arabidopsis thaliana. Fil: Naulin, Pamela A. Pontificia Universidad Católica de Chile; Chile Fil: Armijo, Grace. Pontificia Universidad Católica de Chile; Chile Fil: Vega, Andrea. Pontificia Universidad Católica de Chile; Chile Fil: Tamayo, Karem P. Pontificia Universidad Católica de Chile; Chile Fil: Gras, Diana Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Agrobiotecnología del Litoral. Universidad Nacional del Litoral. Instituto de Agrobiotecnología del Litoral; Argentina Fil: de la Cruz, Javiera. Pontificia Universidad Católica de Chile; Chile Fil: Gutiérrez, Rodrigo A. Pontificia Universidad Católica de Chile; Chile

—Subtribe Chusqueinae was previously composed of the genera Neurolepis and Chusquea. Following molecular-based phylogenetic studies, all species of Neurolepis were transferred to Chusquea and placed in two new subgenera: Chusquea subg. Magnifoliae and Chusquea subg. Platonia. Complete keys for the identification of taxa within C. subg. Magnifoliae and C. subg. Platonia are lacking. The present paper provides five new reports and a taxonomic revision of Chusquea subg. Magnifoliae and C. subg. Platonia in Peru involving 13 taxa. Vegetative and reproductive morphological diagnostic characters were analyzed. Complete illustrations of C. aristata, C. fimbriligulata subsp. peruviana, and C. spectabilis are provided. Chusquea elata, C. fimbriligulata subsp. fimbriligulata, C. mollis, C. nana, and C. spectabilis constitute new reports for Peru. Keys for the identification of the species of Chusquea subg. Magnifoliae and C. subg. Platonia occurring in Peru were prepared based on vegetative and reproductive characters and are here presented for the first time.

Chusquea Kunth (Poaceae, Bambusoideae, Bambuseae) es considerado el genero de bambues lenosos mas rico en especies a nivel mundial. En el extremo sur de Sudamerica, se encuentran numerosas especies de Chusquea que constituyen el componente dominante del sotobosque y son endemicas de la region. La posicion taxonomica de algunas de estas especies ha suscitado mucha controversia. En este trabajo, se presenta la revision taxonomica de las especies nativas del genero Chusquea en Chile, que incluye la sinonimia, descripciones, iconografia, distribucion geografica, habitat, fenologia, nombres vulgares y una clave para la identificacion de las 13 entidades reconocidas (12 especies y una forma) sobre la base de caracteres morfologicos vegetativos y reproductivos. Chusquea andina Phil. y C. gigantea Demoly se incluyen por primera vez en un tratamiento taxonomico, estableciendo sus diferencias con entidades afines y, de esta forma, dilucidando el complejo de especies C. culeou E. Desv. Asimismo, C. fernandeziana Phil. se ilustra en forma completa por primera vez.

A key characteristic of most woody bamboos is the process of cyclical flowering after a long vegetative period. These flowering events are generally gregarious, affecting an entire region, and are followed by the death of individuals. The duration of the life cycle has been determined in very few species. After reconstructing the history of massive reproductive episodes of South American woody bamboo species, the life span of many species was estimated. For most of the species considered, mean flowering period multiples of 15–16 years were found, with an ca. 30-year cycle being the most usual. Evidence of a certain level of reproductive synchrony among different species was found in South America. This survey had also led to several predictions about probable dates of future flowering events. The existence of a relationship between a mass flowering event and climate factors is preliminarily assessed, yielding original results. Although historical records and climate data series are fragmentary, there are some hints that point out a trend that should be taken into account in future studies. Proposed environmental and genetic causes of bamboo flowering are discussed. Finally, the environmental and social consequences of bamboo flowering are listed.

Commercialization of novel adsorbents technology for providing safe drinking water must consider scale-up methodological approaches to bridge the gap between laboratory and industrial applications. These imply complex matrix analysis and large-scale experiment designs. Arsenic concentrations up to 200-fold higher (2000 µg/L) than the WHO safe drinking limit (10 µg/L) have been reported in Latin American drinking waters. In this work, biochar was developed from a single, readily available, and taxonomically identified woody bamboo species, Guadua chacoensis. Raw biochar (BC) from slow pyrolysis (700 °C for 1 h) and its analog containing chemically precipitated Fe3O4 nanoparticles (BC-Fe) were produced. BC-Fe performed well in fixed-bed column sorption. Predicted model capacities ranged from 8.2 to 7.5 mg/g and were not affected by pH 5–9 shift. The effect of competing matrix chemicals including sulfate, phosphate, nitrate, chloride, acetate, dichromate, carbonate, fluoride, selenate, and molybdate ions (each at 0.01 mM, 0.1 mM and 1 mM) was evaluated. Fe3O4 enhanced the adsorption of arsenate as well as phosphate, molybdate, dichromate and selenate. With the exception of nitrate, individually competing ions at low concentration (0.01 mM) did not significantly inhibit As(V) sorption onto BC-Fe. The presence of ten different ions in low concentrations (0.01 mM) did not exert much influence and BC-Fe’s preference for arsenate, and removal remained above 90%. The batch and column BC and BC-Fe adsorption capacities and their ability to provide safe drinking water were evaluated using a naturally contaminated tap water (165 ± 5 µg/L As). A 960 mL volume (203.8 Bed Volumes) of As-free drinking water was collected from a 1 g BC-Fe fixed bed. Adsorbent regeneration was attempted with (NH4)2SO4, KOH, or K3PO4 (1 M) strippers. Potassium phosphate performed the best for BC-Fe regeneration. Safe disposal options for the exhausted adsorbents are proposed. Adsorbents and their As-laden analogues (from single and multi-component mixtures) were characterized using high resolution XPS and possible competitive interactions and adsorption pathways and attractive interactions were proposed including electrostatic attractions, hydrogen bonding and weak chemisorption to BC phenolics. Stoichiometric precipitation of metal (Mg, Ca and Fe) oxyanion (phosphate, molybdate, selenate and chromate) insoluble compounds is considered. The use of a packed BC-Fe cartridge to provide As-free drinking water is presented for potential commercial use. BC-Fe is an environmentally friendly and potentially cost-effective adsorbent to provide arsenic-free household water.

Flowering in bamboo is an unusual event. Documenting flowering individuals or populations provides valuable information about bamboo life cycles. Guadua trinii is endemic to northeastern Argentina, southern Brazil, Paraguay and Uruguay. We here report theflowering of this species in native and cultivated stands in Argentina and confirm its flowering cycle to be of 30-33 years. Floração em bambu é um evento incomum. A documentação de indivíduos ou populações em florescimento fornece informações importantes sobre os ciclos de vida do bambu. Guadua trinii é endêmica do nordeste da Argentina, sul do Brasil, Paraguai e Uruguai. Aqui relatamos o florescimento dessa espécie em agregados nativos e cultivados na Argentina, além da confirmação de seu ciclo de floração por 30-33 anos. Fil: Guerreiro, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Peichoto, Myriam Carolina. 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: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina

El presente trabajo describe e ilustra dos nuevas especies de Chusquea subg. Magnifoliae en Perú, C. longipedicellata y C. rugoloana. Se incluyen claves para la identificación de las especies, basadas en caracteres vegetativos y reproductivos, y una tabla comparativa con los caracteres morfológicos diagnósticos. Se incluyen caracteres micromorfológicos adicionales de las espiguillas y hojas y se presenta una descripción completa de la anatomía foliar. Se incorporan observaciones acerca de las características de las regiones fitogeográficas y la ecología de las nuevas especies. The present paper describes and illustrates two new species of Chusquea subg. Magnifoliae in Peru, C. longipedicellata and C. rugoloana. Keys for the identification of species, based on vegetative and reproductive characters, as well as a comparative table with morphological diagnostic features are included. Additional micromorphological characters of the spikelets and leaves are considered, and a complete description of foliar anatomy is presented. Also, some remarks about the characteristics of the phytogeographical regions and the ecology of these new species are provided. Fil: Alegría Olivera, J. José. Universidad Nacional Agraria la Molina; Perú Fil: Guerreiro, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The present study provides evidence for taxonomic delimitation of Digitaria sect. Trichachne based on morphological data (micro- and macromorphology) and molecular data. A phylogenetic analysis was performed using 121 morphological characters and ITS sequences of 22 species and one variety of Digitaria plus three outgroups. In all topologies (based on morphological, molecular, and combined data) Digitaria sect. Trichophorae was non-monophyletic and nested within D. sect. Trichachne. Digitaria sect. Trichophorae is thus synonymized under D. sect. Trichachne and the circumscription of D. sect. Trichachne is emended. Diagnostic morphological characters related to spikelet structure are described and documented with SEM. A key to taxa belonging to D. sect. Trichachne is provided, as well as a synopsis including synonymy, iconography, geographical distribution, and ecology. The neotype of Trichachne sacchariflora Nees is herein designated. Complete illustrations of Digitaria eggersii, D. hitchcockii, ...

Discarded bamboo culms of Guadua chacoensis were used for biochar remediation of aqueous As(V). Raw biochar (BC), activated biochar (BCA), raw Fe

Background: The present study combines morphological and anatomical studies, cell wall chemical composition analysis, as well as assessment of the nutritional value of Guadua chacoensis foliage leaves.; Results: Foliage leaves of G. chacoensis are a promising source of forage because: (a) as a native woody bamboo, it is adapted to and helps maintain environmental conditions in America; (b) leaf anatomical studies exhibit discontinuous sclerenchyma, scarcely developed, while pilose indumentum, silica cells, prickles and hooks are also scarce; (c) it has a high protein content, similar to that of Medicago sativa, while other nutritional parameters are similar to those of common forages; and (d) glucuronoarabinoxylan, the major extracted polysaccharide, has one-third of the 4-linked β-d-xylopyranosyl units of the backbone substituted mainly with α-l-arabinofuranose as single stubs or non-reducing end of short chains, but also 5-linked α-l-arabinofuranose units, terminal β-d-xylopyranose and d-galactopyranose units, as well as α-d-glucuronic acid residues and small amounts of its 4-O-methylated derivative.; Conclusion: These results constitute the first report on this species, and as culms are utilized in constructions and crafts, the remaining leaves, when used as forage, constitute a byproduct that allows an additional income opportunity. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

Fusoid cells have been interpreted as cells or intercellular spaces, according to different authors. Here, structural and ultrastructural evidence is provided relative to the origin and changes experimented by chlorenchyma cells (“arm cells”) to differentiate into fusoid cells with large intercellular spaces between them. Performed studies and observations were made using Light and Transmission Electron Microscopy. Fusoid cells in Guadua species die but do not remain intact; instead, they uniformly collapse, delimiting conspicuous intercellular spaces which are bigger and different in shape from these cells. In transverse sections of mature and expanded bamboo leaf blades, usually seen in anatomical descriptions, the socalled “fusoid cells” are actually conspicuous intercellular gas spaces delimited by successive collapsed (and rarely not collapsed) fusoid cells. Also, we hypothesize possible relations or links between fusoid cell shape, structural function and apoplastic transport in bamboo leaves. Fil: Vega, Andrea Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina Fil: Castro, María A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina Fil: Guerreiro, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Fil: Alchouron, Jacinta. Universidad de Buenos Aires. Facultad de Agronomia. Catedra de Botanica General; Argentina

Fil: Braccini, Celina L.. Instituto Nacional de Tecnologia Agropecuaria. Centro Nacional de Investigaciones Agropecuarias. Centro de Investigacion de Recursos Naturales. Instituto de Recursos Biologicos; Argentina

Young shoots of Phyllostachys aurea showed glucuronoarabinoxylans (GAX) as the major hemicellulosic components, being extracted in major amounts with 1 M KOH (ratio Xyl:Ara:GlcA, 100:67:8), but also with water, showing a broad structural variability. Mixed linkage glucans were also present, but in minor amounts, mostly concentrated in the 4 M KOH extracts, while pectin polymers were very scarce. Arabinogalactan proteins were an important part of water extracts, determined by the presence of the typical arabinogalactan structures (3- and 6-linked Gal p; terminal and 5-linked Ara f), in addition to small amounts of hydroxyproline (2–3% of total protein) and positive reaction to Yariv's reagent. Morphological and anatomical characteristics of young shoots are described, as well as localization of some cell wall components, and related with chemical analysis. A method for determination of uronic acids as their N-propylaldonamide acetates and separation and quantification by GC/MS was adapted for its use with grass cell wall fractions. Fil: Zelaya Alvarez, Victor Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Química de Biomoléculas; Argentina Fil: Fernández, Paula Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Química de Biomoléculas; Argentina Fil: Vega, Andrea Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; Argentina Fil: Mantese, Anita Ida. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; Argentina Fil: Federico, Ana Ailén. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; Argentina Fil: Ciancia, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones en Hidratos de Carbono; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Química de Biomoléculas; Argentina

Chusquea deficiens Parodi and C. floribunda Guerreiro & Rúgolo, described as endemic to Argentina, are cited for the first time in Bolivia. Morphological diagnostic characters as well as those related to the ecology of C. deficiens and C. floribunda are compared in a table with those of allied and sympatric species. Also, a map showing their updated distribution is included. Fil: Guerreiro, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Peichoto, Myriam Carolina. 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: Vega, Andrea Susana. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

This contribution constitutes the first report of floral reversion and occurrence of pseudovivipary in Paspalum ceresia (Kuntze) Chase, P. stellatum Humb. & Bonpl. ex Flüggé and Thysanolaena latifolia (Roxb. ex Hornem.) Honda. Observations were made in material kept under cultivation in Buenos Aires (Argentina) since March 2001. Proliferating spikelets are described and illustrated, and some implications in the origin of spikelet organs are discussed. An up to date table including the genera of Poaceae where this phenomenon has been documented is also provided. Réversion florale et premier signalement de pseudo-viviparie dans certaines espèces de Poaceae. Cette contribution constitue un premier rapport sur la réversion florale et l’apparition d’épillets pseudo-vivipares dans Paspalum ceresia (Kuntze) Chase, P. stellatum Humb & Bonpl. ex Flüggé et Thysanolaena latifolia (Roxb. ex Hornem.) Honda. Les observations ont été effectuées sur des plantes mises en culture depuis mars 2001 à Buenos Aires (Argentine). Les épillets prolifères sont décrits et illustrés, et quelques conclusions sur l’origine des organes des épillets sont proposées. Nous complétons un tableau mis à jour des genres de Poaceae dans lesquels ce phénomène a été documenté. Fil: Lo Medico, Julia Mariela. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina Fil: Rua, Gabriel Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; Argentina Fil: Bonasora, Marisa Graciela. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Botánica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

A new species of Tarigidia from Puerto Rico is described and illustrated. Additional micromorphological characters of the inflorescence and spikelets are included. This species constitutes the first report of the genus Tarigidia in the New World. Tarigidia axelrodii grows together with Anthephora hermaphrodita and Digitaria bicornis, showing intermediate characters. This species gives additional evidence to support Loxton's hypothesis that Tarigidia is derived from hybridization between Anthephora and Digitaria and also supports the phylogenetic hypothesis showing close relationships between Anthephora and Digitaria.

The grass Paspalum dilatatum Poir. subsp. dilatatum inhabits periodically flooded lowlands as well as non-flooded uplands of the flooding Pampa grasslands (Argentina), while P. dilatatum Poir. subsp. flavescens Roseng., B.R. Arrill. & Izag. inhabits only the upland sites. An experiment was designed to determine if there is local adaptation to flooding in physiological, anatomical and leaf morphological traits. To this end, plants of these populations were subjected to flooding (6 cm water depth) and control conditions (watered daily) for 60 days in an experimental garden. Flooded plants of the subsp. dilatatum from the lowland had 35% higher photosynthesis compared to controls without affecting their stomatal conductance, transpiration rate and leaf water potential. By contrast, both subsp. dilatatum and subsp. flavescens from the upland did not increase their photosynthesis, and had reduced their stomatal conductance and leaf transpiration rate by 35% and 45% when growing in flooded conditions. Upland populations had higher leaf water potential with respect to controls. All populations had high constitutive root aerenchyma (28–42%), and leaf sheath porosity increased by 75% in flooded conditions (from 22–28% to 35–48%). Leaf lengthening differed among populations according to their habitat: subsp. dilatatum from the lowland was the only one that had longer leaf sheaths and blade lengths when flooded. In contrast, flooded plants of subsp. dilatatum from the upland only increased leaf sheath length while subsp. flavescens neither increased leaf blade nor leaf sheath. In conclusion, both the physiological performance and the leaf length plasticity differed among populations. The results agree with those expected based on the species’ habitat, and indicate the better adaptation to the flood-prone habitat of P. dilatatum subsp. dilatatum taken from a lowland area.

This paper constitutes the first report of the chemical nature, and histochemical localization of secretions in Brazilian species of Panicum L. sect. Lorea Zuloaga (Poaceae, Panicoideae, Paniceae); the study also includes an anatomical analysis. Lipid secretions were found in leaf sheaths and ligular regions. Lipids accumulate in specialized epidermal cells, at times surrounding the bases of the macrohairs, and in the mesophyll. Viscous secretions have been previously reported for P. vaginiviscosum Renvoize & Zuloaga and P. acicularifolium Renvoize & Zuloaga, species in section Lorea that are analyzed anatomically here. Lipid secretions are now also reported for the first time in eight other species of section Lorea: P. bahiense Renvoize, P. chnoodes Trin., P. cipoense Renvoize & Send., P. durifolium Renvoize & Zuloaga, P. euprepes Renvoize, P. molinioides Trin., P. poliophyllum Renvoize & Zuloaga, and P. trinii Kunth.

The objective of this work was to study the existence of a trade-off between aerenchyma formation and root mechanical strength. To this end, relationships among root anatomical traits and mechanical properties were analysed in plant species with contrasting root structural types: Paspalidium geminatum (graminaceous type), Cyperus eragrostis (cyperaceous type), Rumex crispus (Rumex type) and Plantago lanceolata (Apium type). Variations in anatomical traits and mechanical strength were assessed as a function of root diameter by exposing plants to 0, 7, 15 and 30 d of control and flooded conditions. For each species, the proportion of root cortex was positively associated with the increment of root diameter, contributing to the increase in root porosity under both control and flooded conditions. Moreover, cell lysis produced an additional increase in root porosity in most species under flooded conditions (except R. crispus). Both structural types that presented a uniseriate layer (epidermis) to cope with compression (Rumex and Apium types) were progressively weakened as root porosity increased. This effect was significant even when the increment of root porosity was solely because of increased root diameter (R. crispus), as when both processes (root diameter and cell lysis) added porosity to the roots (P. lanceolata). Conversely, structural types that presented a multiseriate ring of cells in the outer cortex (graminaceous and cyperaceous types) maintained mechanical strength over the whole range of porosity, in spite of lysogenic processes registered in the inner cortex. In conclusion, our study demonstrates a strong trade-off between aerenchyma formation and mechanical strength in root structural types that lacked a multiseriate ring of tissue for mechanical protection in the outer cortex. The results suggest that this ring of tissue plays a significant role in maintaining the mechanical strength of roots when flooding induces the generation of additional aerenchyma tissue in the root cortex. Fil: Striker, Gustavo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Insausti, Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Grimoldi, Agustin Alberto. Universitat Technical Zu Munich; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentina Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The present study combines morphological and anatomical studies, cell wall chemical composition analysis, as well as assessment of the nutritional value of Guadua chacoensis foliage leaves.Foliage leaves of G. chacoensis are a promising source of forage because: (a) as a native woody bamboo, it is adapted to and helps maintain environmental conditions in America; (b) leaf anatomical studies exhibit discontinuous sclerenchyma, scarcely developed, while pilose indumentum, silica cells, prickles and hooks are also scarce; (c) it has a high protein content, similar to that of Medicago sativa, while other nutritional parameters are similar to those of common forages; and (d) glucuronoarabinoxylan, the major extracted polysaccharide, has one-third of the 4-linked β-d-xylopyranosyl units of the backbone substituted mainly with α-l-arabinofuranose as single stubs or non-reducing end of short chains, but also 5-linked α-l-arabinofuranose units, terminal β-d-xylopyranose and d-galactopyranose units, as well as α-d-glucuronic acid residues and small amounts of its 4-O-methylated derivative.These results constitute the first report on this species, and as culms are utilized in constructions and crafts, the remaining leaves, when used as forage, constitute a byproduct that allows an additional income opportunity. © 2016 Society of Chemical Industry.

Plant volatile organic compounds play a role in selection of host plants by herbivorous insects. Once the insect reaches the plant, contact cues determine host acceptance. Although the willow sawfly Nematus oligospilus (Hymenoptera: Tenthredinidae) can differentiate among willow genotypes, no knowledge is available on the cues used by this insect to seek and accept the host plant. In this study, we recorded behavioral orientation in a Y-tube olfactometer of willow sawfly females to volatiles of the highly preferred genotype Salix nigra and the non-preferred genotype S. viminalis. The volatiles released by undamaged willows of each genotype were analyzed by coupled gas chromatography-mass spectrometry. Contact cues were evaluated first by oviposition preference bioassays after selective leaf wax removal, and then by studying the micromorphology of abaxial and adaxial leaf surfaces and their chemical composition. Willow sawfly females oriented preferentially to S. nigra volatiles, which contained more than 3 times theamount of volatiles than that collected from S. viminalis. Analysis of volatiles showed significant differences in amounts of (Z) and (E)-β-ocimene, undecane, decanal, and β-caryophyllene. The adaxial leaf surface of S. nigra was less preferred after wax removal, suggesting a role of cuticular waxes for oviposition acceptance. No differences were found among the micromorphology of leaf surfaces between preferred and non-preferred genotypes. The chemical analysis of cuticular waxes showed that the abaxial leaf surface of S. viminalis, which is completely avoided for oviposition, possessed 97 % of alkanes. The accepted leaf surfaces contained a more diverse wax profile including alcohols, acids, and esters. Thus, non-alkane wax compounds might be related to oviposition. In sum, our study suggests that several cues act in concert to provide oviposition cues for the sawfly N. oligospilus: females are attracted to volatiles from a distance, and once alighting on the plant, they seek specific chemical contact cues in order to lay eggs. Fil: Braccini, Celina L.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; Argentina Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Coll Araoz, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Teal, Peter E.. United States Department of Agriculture; Argentina Fil: Cerrillo, Teresa. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Delta del Paraná; Argentina Fil: Zavala, Jorge Alberto. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Fernandez, Patricia Carina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Norte. Estación Experimental Agropecuaria Delta del Paraná; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

This paper reviews and adds information about the phenomena of vivipary and pseudovivipary in the Poaceae, which are reported from 21 genera belonging to subfamilies Pooideae, Panicoideae and Chloridoideae. A previously overlooked description of pseudovivipary in Digitaria angolensis is confirmed and constitutes the first record of pseudovivipary in the genus Digitaria. This species is illustrated for the first time and the proliferation phenomenon in the spikelets is described and documented. Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina Fil: Rúgolo, Zulma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina

Tripogon nicorae Rugolo & A. S. Vega, a new species from South America, is described and illustrated. A key for the identification of Tripogon species in America is included and a comparative table based on morphology, leaf anatomy, micromorphological features of the spikelets, and ecology. The taxonomic synopsis includes synonymy, geographical distribution and ecology, iconography, vernacular names, and a list of representative specimens examined. Tripogon ekmanii Nicora & Rugolo is reported for the first time in Uruguay.

Lectotypes of seven names of Andean Chusquea are herein designated on the basis of specimens deposited at MOL and US. The names newly lectotypified are Chusquea huantensis, C. inamoena, C. picta, C. polyclados, C. serrulata, C. straminea and C. tarmensis. Fil: Guerreiro, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The present study describes and illustrates two new species of Chusquea subg. Platonia, C. parodii and C. paucispiculata. Chusquea laegaardii is cited for the first time in Bolivia and C. asymmetrica for Peru. Two keys for the identification of the species, mainly based on vegetative or reproductive characters, and a comparative table with micromorphological diagnostic features of foliage leaf blades are included. Finally, some remarks about the characteristics of the phytogeographical regions and the ecology of these new species are given. El presente trabajo describe e ilustra dos nuevas especies de Chusquea subgén. Platonia, C. parodii y C. paucispiculata. Chusquea laegaardii se cita por primera vez en Bolivia y C. asymmetrica en Perú. Se incluyen dos claves para la identificación de las especies basadas principalmente en caracteres vegetativos o reproductivos y una tabla comparativa con los caracteres micromorfológicos diagnósticos de las hojas del follaje. Se incorporan observaciones acerca de las características de las regiones fitogeográficas y la ecología de las nuevas especies. Fil: Guerreiro, Carolina Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botanica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botanica Darwinion; Argentina Fil: Alegría Olivera, J. José. Universidad Nacional Agraria La Molina. Facultad de Ciencias. Departamento de Biología; Perú Fil: Rugolo, Zulma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botanica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botanica Darwinion; Argentina Fil: Beck, Stephan G.. Universidad Mayor de San Andres; Bolivia Fil: Vega, Andrea Susana. Universidad de Buenos Aires. Facultad de Agronomia. Cátedra de Botanica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

The present study describes the anatomical structure of calyx and leaf glands in Galphimia brasiliensis and analyzes the mechanism of secretion. The glands are marginal and suprabasal, cup-shaped, sessile, and scarcely visible with the naked eye. Light microscopy reveals the following features: a thin, smooth cuticle; unistratified secretory cells; subglandular parenchyma; and vascular bundle supply composed of phloem and xylem with abundant druses of calcium oxalate. Transmission electron microscopy reveals the presence of secretory cells with conspicuous nuclei, dense cytoplasm, lipid droplets, numerous vesicles, mitochondria, Golgi, rough endoplasmic reticulum (RER), and elongated plastids with osmiophilic contents. The secretion reaches the apoplastic space and accumulates beneath the cuticle. Finally, the viscous, translucent exudate is eliminated by mechanical rupture of the cuticle. Histochemical analysis confirms that lipids are the main constituent. Small amounts of polysaccharides were also identified.

Digitaria atra is illustrated for the first time and the original description is emended. The diagnosis of the genus Digitaria is completed by introducing modifications related to the spikelet's morphology and the lower lemma's consistency. Some remarks about the lower palea are included. The unusual morphological characteristics of the spikelet of D. atra are compared with the tribe Isachneae and some genera of Paniceae.

Summary The spikelet of Urochloa paucispicata has a typical Paniceae structure and it constitutes the unit of dispersal; the base of its lower glume is united to an elongated internode between the lower and the upper glumes, and at maturity, it becomes soft and turgid, developing the elaiosome. Chemical identification of TLC fractions in the elaiosome of Urochloa paucispicata showed that it contains triglycerides, free fatty acids and diglycerides. Gas chromatography of the fatty acid methyl esters, of each fraction, showed the presence of palmitic, oleic, linoleic and stearic acids. Palmitic, oleic and linoleic acids are significant components of the lipid fractions. By field observations we identified three different species of ants (Hymenoptera: Formicidae) which removed the spikelets of Urochloa paucispicata and carried them to their nests: Acromyrmex landoltifracticomis FOREL, Pheidole spp. and Ectatomma spp.

A new species of Merostachys from the Bolivian Yungas, Merostachys yungasensis, is described and illustrated. Merostachys yungasensis is compared to other taxa distributed in Argentina, Bolivia, Paraguay, and Peru, in a table based on morphological characters. Additional micromorphological characters of foliage leaf blade and cauline epidermis are included. In Argentina two species are confirmed: M. claussenii and M. multiramea; the latter species constitutes a new report for this country and is excluded from Paraguay. The specific epithet of M. claussenii is emended, and a lectotype is here designated. Two new synonyms are recognized for M. claussenii and its presence is confirmed from Paraguay after an analysis of previous reports based on misidentifications. The taxa are illustrated. A key for the identification of the species, based on vegetative and reproductive characters, is also provided. Fil: Lizarazu, Mabel Angela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Rúgolo, Zulma Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina Fil: Vega, Andrea Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina

Latex and laticifers are reported for the first time in the genera Galphimia and Verrucularia (Malpighiaceae), with description and illustration of the leaf and stem anatomy of both genera. Those genera and the other two in which latex is known (Lophanthera and Spachea) constitute a single tribe, Galphimieae, that is at or near the base of the family’s phylogeny, which suggests that latex in the Malpighiaceae may indicate an ancestor shared with the Euphorbiaceae.

A phylogenetic analysis was performed on 67 species of Digitaria belonging to four subgenera and 26 of the 32 sections recognized in Henrard's monograph. The analysis was based on 113 discrete and six continuous morphological characters. In the resulting topologies the genus Digitaria was monophyletic. In spite of the low support for most groupings, several clades were recovered. The subdivision of Digitaria in the four subgenera proposed by Henrard was not supported since the large subgenus Digitaria appears as a paraphyletic assemblage within which the other three subgenera are nested. Nevertheless, the monophyly of some of Henrard's sections was supported. This is the first approach to the phylogeny of Digitaria. Se llevó a cabo un análisis cladístico. Se incluyeron 67 especies de Digitaria pertenecientes a los 4 subgéneros y a 26 de las 32 secciones reconocidas en la monografía de Henrard. El análisis fue basado en 113 caracteres morfológicos discretos y 6 continuos En las topologías resultantes el género Digitaria resultó monofilético. A pesar del bajo soporte de la mayoría de los grupos, fueron recuperados varios clados. Los resultados no fueron consistentes con la subdivisión de Digitaria en 4 subgéneros propuesta por Henrard, ya que el extenso subgénero Digitaria aparece como un agregado parafilético dentro del cual se hallan anidados los otros tres subgéneros. Sin embargo, la monofilia de algunas secciones fue confirmada. El presente estudio constituye el primer análisis filogenético de Digitaria.