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 Although checklists for most South American countries have been published, some are outdated and there has been no analysis of Solanaceae diversity at country level.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.

In this work, the leaf anatomy of 13 Capsicum species growing in different Biogeographic Provinces was studied. A comparative analysis of theleaf epidermis andits internal structurewas carried outin order to find differences and/or similaritiesamong the species and the presence/absence of mesophytic and/or xerophytic characters according to their environmentconditions.The density of epidermal cells, stomata, trichomes and stomatal index were statistically analyzed. The results showed that all the species have similarcharacters; however, there are some unique features that characterize the species as hypostomatic leaves,presence and types of trichomes, presence or absence of crystalsand its variable disposition, fibers in main vein, and probable presence of tannins.Regarding the presence ofxeromorphic or mesomorphic characters, the differences were not significant among the species from different environments except for the amphistomatic leaves and the abundance of crystals,andtrichomesin speciesfrom dry environments. We conclude that the similarity of the leaf epidermal variables and the internal structure observed in the Capsicum species areresponding more to a grouping according to their phylogenetic relationships than to the environmental conditions where they live.

Se estudió la anatomía foliaren 13 especies de Capsicum L. que crecen en diferentes Provincias Biogeográficas. Se realizó un análisis comparativo de la epidermis foliar y de la estructura interna de lámina y pecíolo para hallar diferencias y/o similitudes entre las especies y la presencia/ausencia de caracteres mesomórficos/xeromórficos según el ambiente que habiten. La densidad de las células epidérmicas propiamente dichas, de los estomas, de los diferentes tipos de tricomas y el índice estomático fueron estadísticamente analizados. Los resultados indican quetodas las especies presentan características similares en sus hojas. Sin embargo, en determinadas especies se observaron algunas particularidades, tales como hojas hipostomáticas, presencia y tipos de tricomas, presencia, disposición y tipo de cristales,fibras rodeando la vena media y probable presencia de taninos. No se encontraron diferenciassignificativasentre especies que habitan distintos ambientes, excepto aquellas especies procedentes de ambientes secos conhojas anfistomáticas y abundancia de cristales y tricomas.Se concluye que las similitudes de las variables epidérmicas y de la estructura interna de la hoja,observadas en las especies de Capsicum, estarían respondiendo a unagrupamiento según sus relaciones filogenéticas más que a las condiciones ambientales donde habitan.