RESUMOPiper L. (Piperaceae) é monofilético, com espécies de difícil distinção taxonômica, sendo necessários ferramentas que auxiliem a identificação interespecífica. Os objetivos do trabalho foram descrever os macropadrões e caracterizar in situ a composição química dos cristais caulinares e foliares de Piper arboreum Aubl. var. arboreum, P. callosum Ruiz & Pav. e P. tuberculatum Jacq., visando avaliar o uso dos cristais para a separação interespecífica. Para tanto, amostras foram submetidas à análise em microscopias de luz e eletrônica de varredura, microanálises espectroscópicas de raios-X por dispersão de energia e testes histoquímicos. Foram observados cristais prismáticos cuneiformes, tabulares, cúbicos e bipiramidais; ráfides; estiloides; drusas de cristais em bloco; rosetas cristalinas de estiloides e concrescências cristalinas. Foram descritos 15 macropadrões cristalinos reunidos em três categorias. Os cristais foram classificados quimicamente como: puros de oxalato de cálcio e misturas entre oxalatos e sulfatos e entre oxalatos, sulfatos e sílica. Rosetas cristalinas, concrescências cristalinas silicificadas e 14 dos 15 macropadrões cristalinos descritos são registros inéditos para inclusões biominerais de Piper e Piperaceae. Os macropadrões cristalinos caulinares e foliares observados são constitutivos e úteis à separação interespecífica das espécies estudadas. Ademais, os cristais desempenham funções relevantes para a autoecologia dos taxa de Piper analisados. PALAVRAS-CHAVE: Cristais, MEV-EDS, Histoquímica, Quimiometria. Silicified crystal concretions and rosettes in Piper (Piperaceae): unpublished reports on their macropatternsABSTRACT Piper L. (Piperaceae) is monophyletic, with species of difficult taxonomic distinction, and thus tools that facilitate interspecific identification are needed. The aims of this study were to describe the macropatterns and characterize in situ the chemical composition of leaf and stem crystals of Piper arboreum Aubl. var. arboreum, P. callosum Ruiz & Pav. and P. tuberculatum Jacq., in order to evaluate the use of the crystals on interspecific distinction. Samples were submitted to analyses under light and scanning electron microscopies, energy-dispersive x-ray spectroscopic microanalyses, and histochemical tests. We observed cuneiform, tabular, cubic, and bipiramidal prismatic crystals; raphides; styloids; blocky crystal druses; styloid crystal rosettes; and crystal concretions. We described 15 crystal macropatterns, which were distributed along three categories. The crystals were chemically classified as: pure calcium oxalate; and mixtures of oxalates and sulfates, and of oxalates, sulfates and silica. Crystal rosettes, silicified crystal concretions, and 14 out of the 15 macropatterns described are unpublished reports on biomineral inclusions in Piper and Piperaceae. The stem and leaf crystal macropatterns observed are constitutive and useful for interspecific separation of the studied species. Moreover, the crystals present relevant functions for the autecology of t...

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Although taxonomic studies indicate that approximately one-third of the genera of Polygalaceae have nodal glands, few anatomical data are available on the structure and ontogeny of these secretory organs. We studied the as yet unknown origin, structure and function of such glands in Polygala laureola. During field observations, we detected glucose in the secretion using Glicofita Plus® and visitors were recorded. Vegetative shoot apices and nodal glands were examined using light microscopy and scanning electron microscopy. The presence of glucose in the secretion allowed us to identify these nodal glands as extranuptial nectaries. Secretory cells occupy a medullary position and are surrounded by phloem. Vascular bundles are concentric, and xylem is only observed at the basal region of the nectary. Nectar is released during the daytime through a pore at the top of the nectary. A stipular origin was confirmed by the fact that the procambial strand is connected to the leaf trace, opposite the leaf gap. The occurrence of stipular extranuptial nectaries in a nodal position is new to Polygala.

Theobroma species have economic importance due to their use in the cosmetic and food industries, mainly in the production of chocolate. However, the anatomy of their vegetative structures remains poorly studied. The goal of this study was to describe the anatomical features of Theobroma grandiflorum, T. speciosum and T. subincanum to contribute to the biological knowledge of these species, as well as provide support to the biotechnological studies of native fruit plants of the Amazon. Leaves at different developmental stages were collected and analyzed under light microscopy and scanning electron microscopy. Sessile and stalked stellate trichomes and digitiform glandular trichomes were observed in the expanded leaves of T. grandiflorum and T. subincanum. These species were also similar in the morphology of the midrib, the organization of the mesophyll and the presence of starch grains in the midrib pith cells. Claviform glandular trichomes and mucilage cells in the epidermis occurred only in the expanded leaves of T. speciosum. The presence of mucilage secretory trichomes in shoot apices (colleters) of all species is a new finding for the genus Theobroma. KEYWORDS: colleters, cupuassu, glandular trichomes, mucilage, stellate trichomes. Caracteres anatômicos foliares de três espécies de Theobroma (Malvaceae s.l.) nativas da Amazônia Brasileira RESUMOAs espécies de Theobroma têm importância econômica devido a sua utilização nas indústrias cosmética e alimentícia, principalmente na produção de chocolate. Entretanto, a anatomia de suas estruturas vegetativas permanece pouco conhecida. O presente estudo teve por objetivo descrever as características anatômicas de Theobroma grandiflorum, T. speciosum e T. subincanum, como contribuição ao conhecimento biológico dessas espécies, bem como, fornecer subsídios aos estudos biotecnológicos de fruteiras nativas da Amazônia. Folhas em diferentes estágios de desenvolvimento foram coletadas e analisadas sob microscopia de luz e eletrônica de varredura. Nas folhas expandidas de T. grandiflorum e T. subincanum foram observados tricomas dos tipos estrelado séssil, pedunculado e glandular digitiforme. Estas espécies também foram similares quanto à morfologia da nervura central, à organização do mesofilo e à presença de grãos de amido no parênquima medular da nervura central. Tricomas glandulares claviformes e células mucilaginosas na epiderme do limbo foliar ocorreram somente em T. speciosum. A presença de tricomas secretores de mucilagem nos ápices vegetativos (coléteres) de todas as espécies estudadas é um novo registro para o gênero Theobroma.

Transfer cells are specialized cells that play an important role where there are high energy costs due to facilitation of transmembrane flow of solutes. This study aimed to investigate the ontogenesis, histochemistry and ultrastructure of glandular trichomes focusing on stalk cells and their possible transfer function. Samples of prophylls of axillary buds, calyces of flowers in anthesis, and flower buds in different stages of development were collected, fixed and processed according to the common methods of microscopy. The glandular trichomes are composed of a secretory head with its cells in columnar format. The stalk is formed by two layers of cells, with the upper layer composed of cuboidal cells where the wall starts to thicken at the beginning of the pre-secretory phase. The secretion is heterogeneous, releasing glucose, other carbohydrates, lipids and phenolic compounds, with two types of release -eccrine and granulocrine. These trichomes are functionally termed as nectaries. The stalk cells appear as transfer cells since they have a thicker anticlinal wall with irregular ingrowths. The presence of transfer cells in the nectaries suggests a high specialization because it improves transport capacity of nectar and compensation in the high energy expenditure for its production and release.

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Anatomical studies involving secreting structures in Stanhopeinae have described lipid-producing structures, the osmophores, these structures have been linked to pollinator attraction. Stanhopea, which belongs to the subtribe Stanhopeinae, has Neotropical distribution and is exclusively pollinated by male Euglossini bees, which are attracted to the aromatic compounds exuded by osmophores-a secreting structure that produces volatile lipids. However, due to the structural diversity found in this genus and the lack of data on which foragers visit these flowers, our aim is to elucidate floral anatomical aspects of the Stanhopeinae group, focusing on the secreting structures of Stanhopea grandiflora Lindl., an orchid that occurs in the Amazon region. Analyses were performed under bright-field microscopy and scanning electron microscopy. Osmophores, nectaries, idioblasts and glandular trichomes were the secreting structures observed in Stanhopea grandiflora. The osmophores are responsible for attracting and offering rewards the male Euglossini bees, which are their exclusive pollinators, while the nectaries offering nectar to the foragers Dolichoderus and Azteca ants which in turn offer protection against herbivores. Nectariferous stomata and glandular trichomes role similar to those of colleters are described in the first record of the subtribe Stanhopeinae.