ABSTRACT
Abstract Limonium brasiliense (Boiss.) Kuntze, Plumbaginaceae, is a coastal herb of the Southern Brazilian states and Rio de Janeiro State. In folk medicine, it is used in the treatment of female genitourinary tract infections and menstrual cycle irregularities. The aim of this study was to describe morpho-anatomical characters with details on venation pattern of L. brasiliense leaves, collected on the coast of Rio Grande do Sul State, in Southern Brazil. Leaf samples fixed in FAA50 (5% formaldehyde, 5% acetic acid and 90% ethanol: water mixture 50:50 v/v) and 1% glutaraldehyde and preserved in 70% ethanol, were histologically sectioned and analyzed by light and scanning electron microscopy. The L. brasiliense leaves were simple, entire, incomplete, oboval-lanceolate, venation penninervous and showed rosulated phyllotaxy, entire and revolute margin, with apex rounded to slightly retuse, base attenuate and venation pattern brochidodromous. On microscopic analysis, these leaves showed a thick and striated cuticle, salt glands, isobilateral mesophyll thicker in the apical region of the leaf blade, abundant aerenchyma in the petiole and main vein, collateral vascular bundles surrounded by fiber-sclereids, lipid substances in the cuticle and polyphenols in phloem cells.
ABSTRACT
Mapania belongs to Mapanioideae, a quite controversial subfamily in Cyperaceae due to the existence of unusual characters in both reproductive and vegetative organs. The genus is represented by seven species in Northern Brazil but taxonomic valuable information related to the leaf organs is still unknown. The present study aimed the anatomical description of the leaf organs (either basal leaves or cataphylls and involucral bracts) of three representative Brazilian species of Mapania. Samples of cataphylls, basal leaves and involucral bracts were sectioned and stained for observations under light microscopy. The involucral bracts provide the most elucidative characters (ten) to distinguish the three species The basal leaves provides six distinguishing characters and are useful to M. macrophylla and M. pycnostachya, as they are absent in M. sylvatica. Mesophyll arrangement in the involucral bracts supports the circumscription of M. macrophylla and M. pycnostachya in M. sect. Pycnocephala and of M. sylvatica in M. sect. Mapania. Some features as thin-walled epidermal cells, stomata level and aerenchyma were considered to be adaptive to the humid environment in which the species occur. The translucent cells are here considered as aerenchyma precursors and a supportive function is assumed for the bulliform cells on the basal leaves and involucral bracts. No silica bodies were found which confirm it as a diagnostic character of Mapania among Hypolytreae genera.
Mapania pertence à subfamília Mapanioideae que apresenta caracteres incomuns às demais Cyperaceae, tanto vegetativos como reprodutivos. O gênero é representado por sete espécies no norte do Brasil e apresenta ainda lacunas de informações especialmente relacionadas aos órgãos foliares. O presente estudo objetivou a descrição anatômica dos órgãos foliares (folhas basais, ou catafilos, e brácteas involucrais) de três espécies representativas de Mapania no território brasileiro. Amostras de catafilos, folhas basais e brácteas involucrais foram seccionadas e coradas para observações em microscopia de luz. As brácteas involucrais foram as mais elucidativas na separação das espécies, com dez caracteres variáveis, uma vez que ocorrem em todas as espécies durante o estágio reprodutivo. As folhas basais forneceram seis caracteres úteis na distinção de M. macrophylla e M. pycnostachya, já que não ocorrem em M. sylvatica. seguidas das folhas basais. O arranjo do mesofilo das brácteas involucrais suporta a circunscrição de M. macrophylla e M. pycnostachya em M. sect. Pycnocephala e de M. sylvatica em M. sect. Mapania. Características adaptativas ao ambiente úmido também foram encontradas, como epiderme com paredes delgadas, níveis dos estômatos e presença de aerênquima. As células translúcidas do mesofilo foram descritas como precursoras de aerênquima e considerou-se que as células buliformes presentes nas folhas e brácteas involucrais apresentam função de suporte desses órgãos. Corpos silicosos não foram encontrados sustentando o seu uso na delimitação de Mapania e dos demais gêneros de Hypolytreae.
ABSTRACT
Aerenchyrna formation has been described in depth in a number of species at a histological level. But large gaps remain in our understanding of its regulation as a developmental process. It is attempted to analyse essential mineral elements like K, Mg, Cu, Zn, Ca and P in the cell wall of aerenchyma cells in petioles ofS. trifolia at five different developmental stages by CSEM-EDX technique. At early stage, K and Cl concentrations in cell wall were high up to 36% and 4.3% of dry weight, respectively. It supported the hypotheses that aerenchyma spaces are filled with liquid at early developmental stages of aerenchyma in S. trifolia petiole. Mg concentration was high at stage 2, up to 0.86% of dry weight. Zinc and Cu were detected only at rapid expansion stages, during which the concentrations were up to 1.5% and 2.5%, respectively. Calcium was detected in the cell wall only at mature stages, the concentration was high up to 1.3% of dry weight at stages 4 and 5. These results confirmed that the element concentration of aerenehyma cell wall undergoes dynamic changes during different developmental stages, and a low Ca with high Zn and Cu concentration are needed for cell expansion. Copper and Zn deposition in the cell wall showed a significant positive linear correlation, suggesting that these two elements share same or similar uptake and transport mechanism in plants.