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Arroyo Cabral, Argentina

Scrivanti L.R.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv | Norrmann G.A.,Institute Botanica del Nordeste IBONE | Anton A.M.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv

The Bothriochloa saccharoides complex is one of the most interesting groups within the genus Bothriochloa (Poaceae). The plants inhabit grasslands of tropical and subtropical regions from the Americas. Principal components analysis (PCA) and discriminant analysis (DA) were employed to evaluate the morphological variation among 60 herbarium specimens tentatively identified as B. imperatoides, B. laguroides, B. longipaniculata, B. saccharoides and B. torreyana. Twenty-three morphological characters were included in the analysis in order to clarify problematic species boundaries. Chemical data was incorporated to improve the resolution on delimitation of the species complex. Taxa were delimited according to the observed clustering of specimens in the PCA plots and discriminant analysis, and diagnostic characters were identified. The results showed that five taxa could be distinguished on the basis of morphological characters and chemical data. Two new subspecies are described: B. saccharoides subsp. americana and B. saccharoides subsp. australis. An identification key and a taxonomic synopsis are provided. © 2013 Magnolia Press. Source

Lopez M.G.,Institute Botanica del Nordeste IBONE | Simpson D.A.,Royal Botanic Gardens
Kew Bulletin

Summary: The taxonomic status of the Bulbostylis capillaris complex in southern South America is re-assessed. B. communis and B. contracta are names proposed for taxa previously assigned to B. capillaris. B. capillaris var. elatior and f. fasciculata are reduced to the synonymy of B. communis var. communis. A new variety, B. communis var. scabrida is described. B. capillaris f. stenantha is placed in synonymy under B. contracta. B. capillaris var. pyriformis is reduced to synonymy under B. loefgrenii (Boeckeler) Prata & M. G. López. B. tenuifolia (B. capillaris var. tenuifolia) is excluded from the Argentinean flora. Some consideration is given to B. capillaris var. microstachys (Scirpus microstachys). © 2012 The Board of Trustees of the Royal Botanic Gardens, Kew. Source

Mignolli F.,University of Pisa | Mignolli F.,Institute Botanica del Nordeste IBONE | Mariotti L.,University of Pisa | Lombardi L.,University of Pisa | And 3 more authors.
Journal of Plant Physiology

In tomato (Solanum lycopersicum Mill.), auxin is believed to play a pivotal role in controlling fruit-set and early ovary growth. In this paper we investigated the effect of the reduced auxin sensitivity exhibited by the diageotropica (dgt) tomato mutant on ovary growth during early stage of fruit development. Here we show that in hand-pollinated ovaries fruit-set was not affected by the dgt lesion while fruit growth was reduced. This reduction was associated with a smaller cell size of mesocarp cells, with a lower mean C values and with a lower gene expression of the expansin gene LeExp2. When a synthetic auxin (4-CPA, chlorophenoxyacetic acid) was applied to the flowers of wild type plants, parthenocarpic ovary growth was induced. On the contrary, auxin application to the flowers of dgt plants failed to induce parthenocarpy. Hand-pollinated ovaries of dgt contained higher levels of IAA compared to wild type and this was not associated with high transcript levels of genes encoding a key regulatory enzyme of IAA biosynthesis (ToFZYs) but with lower expression levels of GH3, a gene involved in the conjugation of IAA to amino acids. The expression of diverse Aux/IAA genes and SAUR (small auxin up-regulated RNA) was also altered in the dgt ovaries. The dgt lesion does not seem to affect specific Aux/IAA genes in terms of transcript occurrence but rather in terms of relative levels of expression. Transcript levels of Aux/IAA genes were up regulated in auxin-treated ovaries of wild-type but not in dgt. Together, our results suggest that dgt ovary cells are not able to sense and/or transduce the external auxin signal, whereas pollinated dgt ovary cells are able to detect the IAA present in fertilized ovules promoting fruit development. © 2012 Elsevier GmbH. Source

Scrivanti L.R.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv | Caponio I.,Institute Botanica del Nordeste IBONE | Anton A.M.,Instituto Multidisciplinario Of Biologia Vegetal Imbiv | Norrmann G.A.,Institute Botanica del Nordeste IBONE
Plant Biology

Mitotic chromosome number of 14 taxa of Bothriochloa native to Argentina, Brazil and Uruguay were surveyed. Chromosome numbers of B. eurylemma, B. meridionalis and B. velutina are reported for the first time, with 2n=6x=60, and this ploidy level is the most common among the studied taxa. In addition, new cytotypes were found for B. alta (2n=60), B. barbinodis (2n=60), B. exaristata (2n=80), B. laguroides var. torreyana (2n=80), B. longipaniculata (2n=60 and 80), B. perforata (2n=60) and B. springfieldii (2n=60). These numbers differ from those reported in the literature. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands. Source

Dematteis M.,Institute Botanica del Nordeste IBONE | Keller H.A.,Institute Botanica del Nordeste IBONE | Vega A.J.,Institute Botanica del Nordeste IBONE
Boletin de la Sociedad Argentina de Botanica

The genus Piptocarpha R. Br. contains 46 species widely distributed from southern Mexico to northeastern Argentina and southern Brasil. The species are scandent shrubs or rarely trees, with axilary inflorescences composed of globose clusters. For Argentina has been only reported to P. sellowii (Sch. Bip.) Baker as the single member of the genus. In the present paper is reported for the first time for Argentina to P. angustifolia Dusén ex Malme, which can be distinguished from the remaining species of Piptocarpha by the tree habit and the inflorescence clusters having a lesser number of heads, among other features. Source

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