RESUMEN
A study on the leaf anatomy of Cordiera sessilis (Rubiaceae), a native medicinal shrub from Brazilian Cerrado was carried out to identify features that may be useful in species recognition. Leaves were collected, fixed and processed by usual techniques, and studied by light and electron microscopy. Quantitative analyzes of stomata and trichomes were performed. In addition to the typical anatomical characteristics of Rubiaceae leaves, two types of vascular patterns were identified in the petiole: in distal part, the vascular system is arranged cylindrically surrounded by sclerenchyma sheath and in proximal part the vascular system is arranged in U-shape coupled to sclerified cells. The micromorphological organization of leaf surface, epicuticular wax types, the petiole pattern and histochemical characteristics as the presence of druses, crystal sand and alkaloids and absence of raphides in the mesophyll, midrib and petiole are considerate representative characteristics of C. sessilis and may be useful in the species recognition.
Um estudo da anatomia foliar de Cordiera sessilis (Rubiaceae), um arbusto medicinal nativo do Cerrado brasileiro foi realizado com o objetivo de identificar características úteis no reconhecimento da espécie. As folhas foram coletadas, fixadas e processadas por meio de técnicas usuais e estudadas em microscopia de luz e eletrônica. As análises quantitativas dos estômatos e tricomas foram realizadas. Além das características anatômicas típicas das folhas de Rubiaceae, dois padrões vasculares foram identificados no pecíolo: na porção distal, o sistema vascular disposto cilindricamente, contornado por uma bainha esclerenquimática e na porção proximal, o sistema vascular organizado em forma de U associado a células esclerenquimáticas. A organização micromorfológica da superfície foliar e da cera epicuticular, o padrão do pecíolo e as características histoquímicas como a presença de drusas, areia cristalina e alcaloides e a ausência de cristais do tipo ráfides no mesofilo, nervura central e pecíolo são consideradas características representativas de C. sessilis e podem ser úteis para o reconhecimento da espécie.
Asunto(s)
Plantas Medicinales , PraderaRESUMEN
Abstract Myrciaria glomerata O. Berg., Myrtaceae, popularly known as "cabeludinha", has high content of ascorbic acid and anti-inflammatory property and is used in folk medicine. The objectives of this study were the morphological, anatomical and histochemical characterization of the leaves. Leaf studies were made with optical, scanning electron and confocal microscopy. The collection of botanical material was held at the Tijuca Forest, Rio de Janeiro, RJ. Histochemical tests aimed the identification of lipids, starch grains, phenolic compounds and crystals. The leaves are simple, opposite, lanceolate, pinnate, hairy, with involute margins, hypostomatic and dorsiventral. The stomata are anomocytic. The epidermis presents simple trichomes. Epidermal cells show uneven thickening of their periclinal outer walls, mainly on the adaxial side of the leaf. Secretory cavities of essential oils are subepidermal and exceed, in height, the palisade parenchyma, formed by one cell layer. Four to five cellular layers, rich in phenolic compounds and lipids form the spongy parenchyma. The bundles are collateral and there are many crystals of calcium oxalate spread throughout the mesophyll. In the midrib and petiole the bundles are bicollateral. Analysis by scanning electron revealed epicuticular wax rod-shaped and as grains. In confocal microscopy, the adaxial epidermis, the fibers and the secretory epithelium of the cavities show autofluorescence. The data obtained are important in quality control exams of samples of this species.