RESUMO

Passiflora organensis is a small herbaceous vine with characteristic morphological variations throughout its development. The plant bears button-shaped extrafloral nectaries exclusively in adult leaves. Extrafloral nectaries are structures that secrete nectar and play an important role in plant-animal interactions as a strategy for protecting plants against herbivory. In this work, we performed anatomical and ultrastructural studies to characterize P. organensis extrafloral nectaries during their secretory phase. We showed extrafloral nectaries in Passiflora organensis are composed of three distinct regions: nectary epidermis, nectariferous parenchyma, and subnectariferous parenchyma. Our data suggests that all nectary regions constitute a functional unit involved in nectar production and release. The high metabolic activity in the nectary cells is characterized by the juxtaposition of organelles such as mitochondria and plastids together plasmalemma. In addition, calcium oxalate crystals are frequently associated to the nectaries. An increasing concentration of calcium during leaf development and nectary differentiation was observed, corresponding to the calcium deposition as calcium oxalate crystals. This is the first description of extrafloral nectaries in Passiflora organensis that is a promising tropical model species for several studies. RESEARCH HIGHLIGHTS: The anatomical and ultrastructural characteristics and the presence of calcium oxalate crystals in the nectary tissue suggest novel strategies against herbivory in the genus Passiflora.

Assuntos

RESUMO

We report for the first time the presence of cluster crystals of calcium oxalate within the glandular trichomes and oil bodies in the mesophyll for Baccharis species. Moreover, the comparative leaf anatomy and micro-morphology of six species of Baccharis, namely B. illinita, B. microdonta, B. pauciflosculosa, B. punctulata, B. reticularioides, and B. sphenophylla is investigated by light and scanning electron microscopy. The studied species exhibited differences in their leaf anatomical features such as the morphology of the cuticle, type and occurrence of the stomata, presence or absence of glandular trichomes, shape of the flagelliform trichomes, and the arrangement of the mesophyll tissues. These differences can be helpful in the species identification and classification and could represent informative characters for the reconstruction of the evolution of the genus.

Assuntos

RESUMO

Abstract Sapium belongs to Euphorbiaceae family and comprises 23 species. Sapium glandulosum (L.) Morong is popularly known in Brazil as "pau-leiteiro" and "leitosinha" and it is used in traditional medicine to cicatrisation. Its leaf extracts have shown analgesic, anti-inflammatory and antibacterial activities. The preliminary set of pharmacognostic tools used for quality assessment of medicinal plant parts is macro- and micro-anatomy and S. glandulosum has not anatomical and histochemical description. Thus the aim of this study was to investigate the anatomical and histochemical characteristics of the leaf and stem of S. glandulosum as a means of providing information for quality assessment of herbal industry. The leaves and stems were investigated by employing field emission scanning electron microscopy, light microscopy, and histochemistry techniques. The analysis showed that S. glandulosum had the following anatomical features: dorsiventral and amphistomatic leaves; paracytic stomata; tabular crystal druses; non-articulated and branched laticifers; midrib's biconvex shape with vascular systems in open arc with invaginated ends; petiole with a round shape and slight concavity on the adaxial side; six collateral vascular bundles in U-shaped organisation; a circular stem shape and a sclerenchymatous ring. In the histochemical tests lipophilic components were found in cuticle and in the latex; phenolic compounds were met in the mesophyll and in the latex; starch grains were found in the parenchymatous sheath; lignified elements were met in the sclerenchymatous ring in the cortex and in the perivascular sclerenchymatous caps, beyond in the vessel elements. These features are helpful when conducting a quality control process.

RESUMO

Schinus terebinthifolius Raddi (Anacardiaceae), conhecida como aroeira-vermelha é uma espécie nativa do Brasil, perenifólia e pioneira, sendo muito utilizada para combater diversas doenças, pois apresenta, entre outras, propriedades anti-inflamatórias e cicatrizantes. O objetivo desta pesquisa foi realizar um estudo morfoanatômico do caule e da folha de S. terebinthifolius, descrevendo a organização dos tecidos e suas possíveis variações. As análises macro e microscópicas foram realizadas com material selecionado de partes vegetativas de um espécime localizado na cidade de Campina Grande - PB. A aroeira-vermelha é um vegetal arbóreo e dióico, que apresenta caule cilíndrico e simpodial, com casca rugosa e estriada. A folha é perene, alterna, coriácea e composta. As análises microscópicas evidenciaram epiderme caulinar e foliar uniestratificadas, exceto na face adaxial da folha, que é bisseriada. No caule e no pecíolo são visualizados muitos tricomas tectores unicelulares, curtos, cônicos e agudos no ápice. Encontram-se canais secretores arredondados e bem desenvolvidos na região do floema em todos os órgãos estudados, bem como cutícula revestindo as células epidérmicas e grande quantidade de drusas de oxalato de cálcio. Os feixes vasculares são circundados por células esclerenquimáticas e apresentam o floema seguido por xilema helicoidal bem desenvolvido. No caule, pecíolo e nervura central da folha, o xilema é interno e o floema, externo. A aroeira-vermelha apresenta alguns aspectos estruturais característicos de plantas xerófilas, como camada múltipla da epiderme da face adaxial foliar, que protegem o mesofilo de excessiva dessecação; presença de cutícula espessa e grande quantidade de pêlos e de estômatos; além de sistema vascular bem desenvolvido, com abundância de esclerênquima, dando sustentação ao feixe.

Schinus terebinthifolius Raddi (Anacardiaceae), popularly known as Brazilian pepper, is an evergreen, pioneer and indigenous plant from Brazil, and it is used to combat various diseases, as it presents anti-inflammatory and wound healing properties. The aim of this research was to study the morpho-anatomical features of the stem and leaf of S. terebinthifolius, describing the organization of the tissues and their variations. The macroscopic and microscopic analyses were performed with material selected from vegetative parts of a specimen collected in the city of Campina Grande - state of Paraíba, Brazil. The Brazilian pepper is a dioecious plant with cylindrical and sympodial stem and rough and striated bark. The leaves are evergreen, alternate, leathery and compound. The microscopic analysis showed uniseriate epidermis in the stem and leaf, except in the adaxial leaf, which is biseriate. In the stem and petiole, many unicellular, short, conical tector trichomes with acute apex are observed. In the phloem of all studied organs, we found rounded and well-developed secretory ducts, as well as cuticle covering the epidermal cells and a large amount of calcium oxalate druses. The vascular bundles are surrounded by sclerenchyma cells and present phloem followed by well-developed spiral xylem. In the stem, petiole and leaf's central vein, the xylem is internal and the phloem is external. The Brazilian pepper has some structural features characteristic of xerophilous plants, such as multiple layers of the epidermis in adaxial leaf, which protects the mesophyll from excessive drying, thick cuticle and a large quantity of hairs and stomata, well-developed vascular system with plenty of sclerenchyma, giving support to the bundle.

Assuntos