Biología Vegetal

Background: Deep learning methods have outperformed previous techniques in most computer vision tasks, including image-based plant phenotyping. However, massive data collection of root traits and the development of associated artificial intelligence approaches have been hampered by the inaccessibility of the rhizosphere. Here we present ChronoRoot, a system that combines 3D-printed open-hardware with deep segmentation networks for high temporal resolution phenotyping of plant roots in agarized medium. Results: We developed a novel deep learning-based root extraction method that leverages the latest advances in convolutional neural networks for image segmentation and incorporates temporal consistency into the root system architecture reconstruction process. Automatic extraction of phenotypic parameters from sequences of images allowed a comprehensive characterization of the root system growth dynamics. Furthermore, novel time-associated parameters emerged from the analysis of spectral features derived from temporal signals. Conclusions: Our work shows that the combination of machine intelligence methods and a 3D-printed device expands the possibilities of root high-throughput phenotyping for genetics and natural variation studies, as well as the screening of clock-related mutants, revealing novel root traits.

Key to the recognition of indigenous tree and shrub species from Sitio Ramsar Jaaukanigás (Province of Santa Fe, Argentina). The recognition of native vegetation is the first step on biological conservation and management planning in protected areas. The ligneous species of Paraná River floodplain are essential to fluvial ecosystem functioning; and, several of them are used by local inhabitants to made foods and medicines, or like primary source of wood, tannin and wild honey productions. Despite the high tree and shrub fluvial ecosystem diversity, to the present there is not any work that involves it and that facilitates its botanical recognition. The goal of this paper was to perform a friendly systematic tool to botanical recognition at field and vegetative stage of indigenous tree and shrub species from Sitio Ramsar Jaaukanigás (Santa Fe, Argentina), an area that encompass a high ligneous floristic diversity. A total of 36 characters relative to the general aspect, trunk, top and leave were observed to each taxon. The botanic key presented here, which include 50 species distributed in 44 genera and 23 families, is based on easily readable botanical characters and try to became in an accessible tool to amateurs and professionals.

With 7 Figures Summary As a contribution to the knowledge of inflorescences within the tribe Paniceae, the inflorescences of American species of Srrariu are analyzed typologically. All the inflorescences in Seturiu are polytelic and truncated. Inflorescence structure is considerably variable among species within this genus, ranging from highly developed to remarkably reduced panicle like inflorescences, both in terms of branching as well as in the relations of internode length, The main axis and the paracladia end in sterile units (setas or bristles). The spikelets are the coflorescences of paracladia lacking a pdrac ladial zone. The pedicels can be interpreted as basal florescence internodes. The setae can be considered as a sterile part of the rachis; the distal part of either the main axis or a paracladium that bears a basal spikelet. This spikelet represents the coflorescence of a paracladium of higher order than the seta.

Desmanthus paspalaceus (Lindm.) Burkart belongs to the D. virgatus complex, subfamily Mimosoidae. The known potential as livestock fodder of several of these legumes prompted us to undertake a phenotypic, molecular, and symbiotic characterization of the D. paspalaceus symbionts in the Santa Fe province, Argentina. The rhizobia collected-containing isolates with different abiotic-stress tolerances-showed a remarkable genetic diversity by PCR fingerprinting, with 11 different amplification profiles present among 20 isolates. In selected isolates 16S-rDNA sequencing detected mesorhizobia (60%) and rhizobia (40%) within the collection, in contrast to the genus of the original inoculant strain CB3126-previously isolated from Leucaena leucocephala-that we typified here through its 16S rDNA as Sinorhizobium terangae. The results revealed the establishment by diverse bacterial genera-rhizobia, sinorhizobia, and mesorhizobia-of full N 2-fixing symbiotic associations with D. paspalaceus. This diversity was paralleled by the presence of at least two different nodC allelic variants. The identical nodC alleles of the Mesorhizobia sp. 10.L.4.2 and 10.L.5.3 notably failed to group within any of the currently described rhizo-/brady-/azorhizobial nodC clades. Interestingly, the nodC from S. terangae CB3126 clustered close to homologs from common bean nodulating rhizobia, but not with the nodC from S. terangae WSM1721 that nodulates Acacia. No previous data were available on nod-gene phylogeny for Desmanthus symbionts. A field assay indicated that inoculation of D. paspalaceus with the local Rhizobium sp. 10L.11.4 produced higher aerial-plant dry weights compared to S. teranga CB3126-inoculated plants. Neither the mesorhizobia 10.L.4.2 or 10.L.5.3 nor the rhizobium 10L.11.4 induced root nodules in L. leucocephala or P. vulgaris. The results show that some of the local isolates have remarkable tolerances to several abiotic stresses including acidity, salt, and temperature; while exhibiting prominent N 2 fixation; thus indicating suitability as candidates for inoculation of D. paspalaceus.

Vegetation and flora or the Universitary farm school reserve of Esperranza (Santa Fe, Argentina). The Esperanza's School Farm Reserve (UNL) is an algarrobo and quebracho blanco xerofitc forest relict of 64,7 hectares, located in the Espinillares and Algarrobales Pampean region. In this work, the flora of the reserve is described and the vegetation units are identified and characterized, E. Exner et al. 54 | Revista FAVE-Ciencias Agrarias 3 (1-2) 2004 in its topological, structural, botanical and fenological aspects, as a part of the reserve evaluation for its later design. Six vegetation units were distinguished: successional forest; savanna of Prosopis sp. and Geoffroea sp. with halophilous grasses; Prosopis sp. and Geoffroea sp. forests; Gleditsia triacanthos forest; Aspidosperma quebracho-blanco forest and chilcal shrubland. 330 botanical taxa were identified corresponding to 70 families, 226 genus, 263 species and 67 subspecific taxa. Of this total, 0.3% corresponded to Gimnosperms and 99.7% to Angiosperms. 75.4% of the Angiosperms were Dicotyledons (60 families, 173 genus) and 24,6 % Monocotyledons (9 families, 52 genus). The families better represented were: Asteraceae (39 genus, 67 taxa) and Poaceae (38 genus, 59 taxa). Of the 330 taxa registered, 87.6% were native ones, 10.3 % naturalized, 1.2% were endemic from Argentina and 0.9 % were adventitious. According to their form of life, 80.3 % of the plants were herbaceous, 8.5 % bushes, 4.8 % voluble plants, 3.9 % trees, 0.9 % succulent%, 0.9 % epifitic and 0.6 % hemiparasitic.

Sporobolus phleoides is an endemic grass of Argentina considered an important genetic resource for saline environments due to its salinity tolerance. Basic information about its reproductive biology is needed to adequately preserve its genetic variability. Hence, we studied its breeding system through phenology, embryological analysis, and self-pollination versus open-pollination treatments in six populations collected from four provinces of Argentina. The results indicated that S. phleoides is mainly autogamous with a high fertility rate. Cleistogamous and chasmogamous spikelets are isomorphic and occur simultaneously on the inflorescence, with higher percentages of cleistogamy found in the basal region of the panicle. The average percentage of cleistogamy during the study period was 23 % for all populations evaluated. The development of the embryo sac follows the typical pattern of grasses and indicates normal sexual reproduction. This study provides the basis for programming genotype collections for gene banks and future plans of domestication.

The Argentine germplasm of the Desmanthus virgatus complex is a valuable group of legume species for animal production. However, little is known about the extent and nature of the variability of these species. This study, which is an introduc-tion to further ones about the variability of these species, aims at: a) collecting representative germ-plasm; b) analysing the morphological diversity; and c) determining patterns in Argentine popula-tions of potential forage species of the D. virgatus complex using PCA and cluster methods. Twenty-six populations of D. virgatus, D. acuminatus and D. paspalaceus collected in Argentina plus cv. Marc were used to evaluate 14 quantitative mor-phological characters. Collecting expeditions, examination of material collected and analyses of measurements permitted the first characterisation of the morphological diversity and determination of the patterns of variation of species with forage value within the Argentinian D. virgatus complex. Identifying ...

Setaria lachnea, moha perenne, is a native grass with excellent forage quality; thus, its introduction to cultivation has been recommended. Therefore, in the present study, the variability in flowering phenology and reproductive success of three Argentine populations from different places by altitudinal gradient have been analyzed, with respect to points of interest for selecting materials. A completely randomized experimental design was used, with 10 genotypes per population and 3 replications per genotype. Flowering phenology was analyzed through variables of flowering start and mid-flowering; the number of panicles was quantified by observation, the number of the total of panicles and reproductive success by fruiting percentage. For flowering start only significant (p£0.05) intrapopulation variations were found. Seventy-five percent of the genotypes started flowering in November 2005. For mid-flowering, there were significant inter-and intra-population differences (p£0.05). The intrapopulation variability observed will allow selecting genotypes with prolonged vegetative period. Reproduction success, measured as mean fruiting percentage, was 41 (high for a nondomesticated species), with variation from 3 % to 80 %. In the two analyzed years (2005-2006), significant inter-and intra-population differences (p£0.05) were found. Genotypes of the population of less height stood out by their high fruiting percentage, always above 40 %; however, there was no variation pattern associated to altitude. Beginning of flowering was not correlated with fruiting percentage; therefore, it will be possible to select late-ripening materials, without altering fruiting percentage.

La domesticación de especies del género Setaria se inició hace 6000 y 9000 años AC en Eurasia y en América, respectivamente (Callen, 1967; Li & Wu, 1996). Entre las especies forrajeras domesticadas del género se destaca S. italica (L.) P. Beauv. (moha de Hungría), por ser de ciclo anual, de rápido crecimiento y buena producción estival temprana de biomasa de calidad la que puede ser utilizada a través de pastoreos directos o como recurso invernal a través de la confección de heno o silo (Josifovich & Echeverria, 1971). Setaria magna Griseb. (conocida por su nombre vulgar en ingles como "giant bristlegrass") es una especie anual, de metabolismo C4, vigorosa, con

Caponio, I. & Pensiero, J. F. 2002. Cytological and reproductive behaviour of Setaria pflanzii (Poaceae). Darwiniana 40(1-4): 17-23. Setaria pflanzii is a wild species native to northwestern Argentina, SE of Bolivia and NE of Paraguay, with a potential of forage production and good palatability. The objective of this work was to determine its chromosome number, meiotic chromosome behavior and reproductive

At a regional scale, changes in tree and herbaceous cover relative to topographic variation have been observed in the landscape of Chaco region. Nonetheless, structural and floristic variations associated with topography are quite unknown at local scale. This study surveys the forests of Santafesinian Humid Chaco with special concern to the variation of structure and floristic composition along the topographic gradient. Twenty transects of 150 m each were used to determine frequency, density and DBH of tree and bush species. In short, 21 tree, 19 young tree and 16 bush species were registered. The tree species belonged to 18 families and 30 genera, and the richest family was Fabaceae with 11 species. In forest where the low topographic sites were dominant, frequency of young and adult trees were high and low, respectively. In contrast, richness and diversity indexes did not show changes along the same gradient. Results are discused in relation to regional ecological knowledge of S. balansae forests.

Sporobolus phleoides Hack. is an endemic grass of Argentina that is considered an important genetic resource for saline environments. Knowledge of its germination behaviour is an indispensable requirement for the future potential use of this species. Thus, the effects of different factors on germination were evaluated in six representative populations collected from plants cultivated in a uniform environment. In addition, we investigated how the different parts of the seed contributed to dormancy and intraspecific variability. S. phleoides has non-deep physiological dormancy that appeared to be related to its testa. Thereby, dormancy was completely removed with puncturing treatments. High levels of germination were also obtained in seeds stratified at 8°C over 100 days in a solution of nitrates. After-ripening treatment did not have a significant effect in breaking dormancy. Similar germination behaviour and dormancy levels were observed in the different populations, especially when...

Los Bajos Submeridionales constituyen una extensa área del norte de Argentina que abarca cerca de 5 millones de has en las provincias de Santa Fe, Chaco y Santiago del Estero. La principal actividad productiva de los Bajos Submeridionales, y de los ambientes salinos en general,es la ganadería, la que se realiza en forma extensiva basada en el uso de los pastizales. Las limitantes ambientales que condicionan la producción de forraje son la salinidad de sus suelos y los períodos de inundaciones y sequías. La fl ora de los Bajos Submeridionales ofrece un número signifi cativo de especies que deberían ser conservadas, estudiadas e introducidas a cultivo como recursos forrajeros. El trabajo menciona los elementos a considerar para desarrollo de unprograma de introducción a cultivo de RFNyN para incrementar la oferta forrajera de los Bajos Submeridionales. La base del esquema reside en la identifi cación y caracterización de especies promisorias, aspectos en los que existen pocos trabajos...

Summary: Germinative behavior and forage potential of Setaria magna (Poaceae). Setaria magna Griseb. is an American species that grows well in damp, swampy environments either in fresh or salt water. It is an annual, grass with vigorous plants in their natural habitat. In this study the germinative behavior as well as the forage potential of this species were evaluated. Caryopses viability and their germination ability at different temperature regimes were analyzed, by means of different scarification treatments and temperatures from diverse environments and harvest times. Morphological and productive traits in genotypes of a population in vegetative and reproductive states were evaluated in field. Results showed that caryopses viability remained the same during the first year after harvest and then decreased. Covered caryopses did not germinate at any of the temperatures tested, which suggests dormancy, whereas in naked caryopses alternating temperature allowed a greater percentage...

he area of the Saladillos lies at the eastern part of the of Santa Fe province center, comprising the western halves of the Garay and San Javier departments and small parts of other administrative units. At its western limits are the Toba and Saladillo Amargo rivers,