Resumo

BELTRAMINI, Verónica  e  ZAPATA, Ricardo. Morphological adaptations of the Ramorinoa girolae (Fabaceae) seedling to arid contidions. Lilloa [online]. 2020, vol.57, n.1, pp.1-12. ISSN 0075-9481.  http://dx.doi.org/doi.org/10.30550/j.lil/2020.57.1/1.

The morphological adaptations to arid environmental conditions of Ramorinoa girolae Speg. (Fabaceae), during the stages of vegetative cotyledonal and expanded second nomophile, were studied. Seeds of a natural population from La Rioja province were germinated at an ambient temperature of ± 20 °C to record and evaluate events during germination and seedling. Freehand cross-sections were made to the vegetative organs and these were dyed in astra blue and safranine, then they were photographed with a binocular microscope and a Nikon digital camera. The seedlings showed a phanerocotylar germination with an extensive main root. From the first and second knot, leaves with alternate arrangement were observed, once they died, the stems fulfilled the function of photosynthesis. In its anatomy, it shows a tetrarch root, unistratified rhizodermis and cortical parenchyma with endodermis at primary stage. The hypocotyl has a circular or subcircular border, a thin cuticle with an unistratified epidermis, open vascular bundles distributed in eustele and parenchymatous medulla with amyloplasts. In the first internode of the epicotyl, a unistratified epidermis with thick cuticle was observed. The bark presents a laminar collenchyma interspersed with a palisade chlorenchyma, a division of the vascular bundles, and a development of the cambium. In the second internode, the epicotyl shows a circular border, a bistratified epidermis with thickened cuticle, unicellular non-glandular trichomes and small ribs due to the presence of sunken stomata. At a subepidermal level, it shows a cholenchymatous hypodermis. The bark is made up of palisade chlorenchyma. The vascular bundles have phloem with a cap of gelatinous fibers. The leaves present a uniestratified epidermis with unicellular non-glandular trichomes on the adaxial side and dorsiventral mesophyll. In conclusion, the morphological characters of the R. girolae seedling described in this study allows us to introduce adaptive characters of the species to arid environmental conditions.

Palavras-chave : Adaptations; anatomy; aridity; legume; xerophytic.