ABSTRACT Although knowledge about halophytic Solanaceae is scarce, it is known that several species within genus Lycium tolerate salinity. Lycium humile grows in highly saline soils in mudflats near saline Andean lakes. This study evaluated the germination responses of L. humile under different scarification methods, photoperiods, temperatures and saline conditions and, simultaneously, tested seedling survival under different iso-osmotic conditions. Dormancy and germination were found to be regulated by interactions with different factors, with the highest germination percentages being obtained by immersion in sulfuric acid, with a temperature of 25 °C and a temperature regime of 5/25 °C, under which seeds were neutrally photoblastic. As osmotic potential of saline solutions decreased, germination also decreased drastically but the seedling survival percentage was higher than 30 % at 600 mM NaCl. No seeds germinated in any of the polyethylene glycol (PEG) solutions and no seedling survival was observed from -1.2 MPa PEG solutions. More than 90 % of seeds incubated in NaCl were able to recover germination after being transferred to distilled water, independently of NaCl treatments. We concluded that the effects of extreme environmental conditions on germination responses and seed tolerance to salinity may determine the occurrence and restricted distribution of L. humile.

Abstract Solanaceae is one of the most diverse families in the Americas, particularly in Argentina where it represents the fourth family in terms of species number. Although checklists for most South American countries have been published, some are outdated and there has been no analysis of Solanaceae diversity at country level. We present an updated summary of Solanaceae diversity in South America, an analysis of its distribution in Argentina, and preliminary conservation assessments for all species endemic to Argentina. Regression analyses were used for evaluating the ratio between taxa/area and endemic/total species, multivariate ordering methods were used to analyze the relationships between Argentine ecoregions, and the IUCN criteria were applied for conservation assessments. Results show that Solanaceae comprises 1611 species in South America. The highest diversity is in Peru, which, together with Ecuador, possesses more diversity than expected for the area; Chile and Brazil have the greatest percentage of endemic species. In Argentina, the Chaco ecoregion hosts the highest number of taxa, but largest number of endemic species is found in the Monte ecoregion. According to the IUCN criteria, 28 endemic species from Argentina are considered threatened. We discuss South American countries and Argentine ecoregions in terms of conservation priorities.

The flora and the vegetation of basaltic outcrops of Los Cóndores Mountains, central Argentina, are described. Plant communities were sampled following the Braun-Blanquet methods. The 98 relevés × 272 species matrix was classified through the ISOPAM method. The classification discriminated three main communities occurring in the three different substrates explored in this landscape: Rocky Islands (inselbergs), a Natural Matrix surrounding the Islands and an Agricultural Matrix, surrounding the whole basaltic area. The three communities differed in composition and physiognomy: the Islands were the less disturbed sites, reporting the highest plant species richness and diversity as well as the higher number of endemics, and the lowest number of exotic species. In the other extreme of the disturbance gradient, the Agricultural Matrix showed the opposite patterns and is dominated by annual and perennial herbs, mainly weeds. While the number of aliens is low in the Islands and in the Natural Matrix, almost 50% of the species are exotic in the Agricultural Matrix. The results of this study reveal that the basaltic inselbergs are relevant sites for the conservation of the natural heritage.

Se decribe la flora y la vegetación de pasiajes basálticos de la Sierra de Los Cóndores, Córdoba, Argentina. La vegetación se estudió según criterios de la escuela de Braun-Blanquet; la matriz de 98 inventarios × 272 spp. fue clasificada a través del método ISOPAM. El análisis discrimina tres comunidades correspondientes respectivamente a las tres geoformas relevadas en estos paisajes: Islas rocosas (inselbergs), la Matriz Natural que rodea a las Islas y la Matriz Agrícola que circunda al complejo de paisajes basálticos. Las tres comunidades difieren en su composición florística: las Islas rocosas son los sitios menos perturbados, más ricos en especies, con mayor diversidad, mayor número de especies endémicas y su fisonomía está dominada por formas arbustivas. En el otro extremo, la Matriz Agrícola es la más pobre en especies, la de menor diversidad y endemicidad, y predominan las hierbas perennes y anuales. Las Islas rocosas y la Matriz Natural registran bajos números de especies exóticas en su composición, mientras cerca del 50% de la flora de la matriz agrícola se compone de especies adventicias. Los resultados de este estudio revelan la importancia de las islas rocosas basálticas para la conservación del patrimonio natural de la provincia de Córdoba.

ABSTRACT Achyrocline satureioides (Lam.) DC. Asteraceae, ‘marcela del campo', possess several pharmacological properties. Previously we reported antiviral activity of an aqueous extract of A. satureioides against an alphavirus, Western Equine Encephalitis virus. Alphaviruses are highly virulent pathogens which cause encephalitis in humans and equines. There are no effective antiviral to treat its infections. The aim of this study was to evaluate in vitro cytotoxic and antiviral activities against Western Equine Encephalitis virus of five water extract chromatographic fractions from A. satureioides and identify the main compounds of the bioactive fraction. Also, it was to assess in vivo cytogenotoxic ability of the active fraction. Cytotoxicity studies revealed low toxicity of the most of fractions in Vero and in equine peripheral blood mononuclear cells. Antiviral studies showed that the water crude extract – Sephadex LH 20 – fraction 3 MeOH–H2O (Fraction 3) was active against Western Equine Encephalitis virus with Effective Concentration 50% = 5 µg/ml. Selectivity Indices were 126.0 on Vero and 133.6 on peripheral blood mononuclear cells, four times higher than aqueous extract selectivity index. Regarding the mechanism of action we demonstrated that F3 exerted its action in intracellular replication stages. Further, fraction 3 showed important virucidal action. Fraction 3 contains, in order of highest to lowest: chlorogenic acid, luteolin, 5,7,8-trimethoxyflavone, 3-O-methylquercetin and caffeic acid. Fraction 3 did not induce in vivo toxic nor mutagenic effect. Therefore, it is safe its application as antiviral potential. Further studies of antiviral activity in vivo will be developed using a murine model.

Vegetation of carbonate outcrops in mountains of central Argentina. In mountains of Central Argentina, which have severe fragmentation and replacement of natural vegetation, rocky outcrops are important habitats for biodiversity conservation, as refuges for endemic and rare species. In this paper, we explore the local compositional variation of vegetation in calcium and dolomitic outcrops of Sierras de Córdoba and compare associations between different geochemical types and floristic composition along a local altitudinal gradient. Four adjacent outcrops of different geochemical types located in different positions in a local elevation gradient from 1000 to 1800 m.a.s.l. were selected and cover-abundance of all vascular plants at 216 rélevés, was estimated. Significative differences of compositional vegetation attributes occurred between the different lithologies and altitudinal strata. At the local scale, the floristic composition appeared related to the geochemical typology of outcrops and this pattern is overlapped with altitude. It was possible to establish relationships between the presence of different vascular plants and different types of calcitic and dolomitic rocks, independently of their position in the altitudinal gradient. The importance of these variables in structuring the habitat and filtering of species is confirmed, and its importance in looking for priorities in conservation of these singular habitats.

En las montañas del centro de Argentina, con una intensa fragmentación y reemplazos de la vegetación natural, los afloramientos rocosos constituyen hábitats importantes para la conservación de la biodiversidad, como refugios de especies endémicas y raras. En este trabajo se exploró la variación composicional local de la vegetación en afloramientos de mármoles cálcicos y dolomíticos de las sierras de Córdoba y se compararon las asociaciones entre diferentes tipologías geoquímicas y la composición florística en un gradiente altitudinal. Se relevaron cuatro afloramientos adyacentes de tipologías geoquímicas diferentes localizados en diferentes posiciones en un gradiente de altitud desde 1000 hasta 1800 msm, estimándose abundancia-cobertura de todas las plantas vasculares en 216 censos. Los atributos composicionales estructurales de la vegetación revelaron diferencias significativas entre litologías similares en diferentes estratos altitudinales y entre diferentes litologías para un mismo estrato altitudinal. La composición florística local está relacionada con la tipología geoquímica de los afloramientos y la altitud se sobrepone a ese patrón. Se establecieron relaciones entre la presencia de diferentes especies vegetales y tipologías de rocas calcíticas y dolomíticas de manera independiente a su posición en el gradiente de altitud. Se confirma la importancia de estas variables en la estructuración del hábitat y filtrado abiótico de especies y la importancia de su conocimiento para establecer prioridades en su conservación.

On the presence of Amaranthus palmeri (Amaranthaceae) in Argentina. Amaranthus palmeri, a species native from USA and Mexico, is cited for the frst time for the Argentinean adventitious fora mainly in the Córdoba province and also in San Luis and La Pampa provinces. The species is described and illustrated and their geographical distribution is mentioned.

Amaranthus palmeri, especie nativa de Estados Unidos de Norte América y México, se cita por primera vez para la fora adventicia argentina sobre la base de ejemplares coleccionados principalmente en la provincia de Córdoba, además de San Luis y La Pampa. Se describe e ilustra la especie y se menciona su distribución geográfca.

Rock outcrops are important habitats for biodiversity conservation. This paper provides a catalog of species of vascular plants that grow on limestone (marble) and serpentinites of the Sierra de Córdoba, describing the compositional variation of its flora and exploring the lithological-geochemical control on the distribution of the floristic groups. Thirty-one (31) outcrops were surveyed in an area that extended about 280 km in latitude and 120 km in length (30 ° 42 &#';33 ° 5' Lat. South 64 ° 20 &#';65 ° 20' Long. West) and from 500 m.s.m. to 2000 m.s.m. The average sampling area in each outcrop was approximately 2725 m² where the inventory of all vascular plant species and the lithological sampling for subsequent evaluation of the rock geochemistry were performed. There were 404 species distributed in 67 families and 255 genera. Six new records for Córdoba province are provided. The endemoflora of all studied outcrops comprises 88 species. The average species richness of the outcrop was 68 and the average diversity H = 4.14. The total of medicinal species in the outcrops was 212. The hemicryptophytes (52%), chamaephytes (17%), phanerophytes (16%) and geophytes (9%) were the dominant life form. The floristic composition at the regional level, variable along the geographic gradient (and climate), overshadows local environmental variation (geochemistry, altitude) between the outcrops. Using available data richness, diversity, number of endemic species and rarity we could identify a minimum set of otcrops that should be included in conservation plans in both the provincial and national level.

Los afloramientos rocosos constituyen hábitats importantes desde el punto de vista de conservación de la biodiversidad. En este trabajo se provee de un catálogo de las especies de plantas vasculares que crecen en los afloramientos cálcicos y dolomíticos (mármoles) y serpentinitas de la Sierra de Córdoba, se describe la variación composicional de su flora y se explora su relación litológico-geoquímica sobre la distribución de los grupos florísticos detectados. Treinta y uno (31) afloramientos fueron relevados en un área que se extendió en unos 280 km de latitud y 120 km de longitud (30° 42&#'; a 33° 5&#'; Lat. Sur y 64° 20&#'; a 65° 20&#'; Long. Oeste) y desde los 500 m.s.m hasta los 2000 m.s.m. El área promedio relevada en cada afloramiento fue de aproximadamente 2725 m2 en donde se realizó el inventario de todas las especies de plantas vasculares presentes, su colección y el muestreo litológico para la evaluación posterior de la geoquímica de las rocas. Se registraron 404 especies distribuidas en 67 familias y 255 géneros. Se mencionan 6 citas nuevas para la provincia. La endemoflora de los 31 afloramientos comprende 88 especies. La riqueza promedio de especies de los afloramientos fue de 68 y la diversidad promedio de H = 4,14. El total de especies medicinales relevadas en los afloramientos fue de 212. Las hemicriptófitas (52%), caméfitas (17 %), fanerófitas (16%) y geófitas (9 %) fueron las formas de vida predominantes. La composición florística a nivel regional, variable a lo largo del gradiente geográfico -y climático-, se sobre impuso a la variación local ambiental (geoquímica, altitud) entre los afloramientos. Se identificó un número mínimo de sitios a conservar que incluyen la máxima biodiversidad a través de los datos disponibles de riqueza, diversidad, número de especies endémicas, y rareza.