Histochemical Tests Research Articles

Structure and histochemistry of medicinal species of Solanum

Studies on native medicinal plants strengthen initiatives to preserve the environments where those species naturally occur, many of them already strongly menaced even before their potential to humankind is known. Root and stem barks, leaves, and pericarps samples of Solanum agrarium Sendtn., S. lycocarpum A. St.-Hil., S. palinacanthum Dunal, S. paniculatum L., and S. stipulaceum Roem. & Schult., species that occur in the Cerrado (Brazililan savanna) were processed according to common light microscopy techniques for structural analysis, and histochemical tests were performed to locate and identify classes of chemical compounds. The distinctive features identified were low concentration of crystal sand in the root and stem, presence of terpene resin in the root, and absence of hypodermis in the leaf, in S. agrarium; bright spots (group of sclereids) in the root, isobilateral mesophyll, thickened cell walls with hemicelluloses and strong aroma in the fruit, in S. lycocarpum; high concentration of crystal sand in the root and stem, oval-shaped limb, presence of isolated crystals in the exocarp, in S. palinacanthum; strong sclerification and rays with great height in the root and stem, in S. paniculatum; and accumulation of soluble protein in the root and stem, presence of conspicuous membranaceous stipules, absence of spiniform trichomes, in S. stipulaceum. This work identifies distinctive structural features, its ecological importance, and determines the distribution of secondary compounds associated with the medicinal properties reported for these species and contributes to the conservation of the natural environments where they occur.

Limoniastrum monopetalum (L.) Boiss, a Candidate plant for use in Urban and suburban Areas with Adverse Conditions. An Anatomical and Histochemical Study.

Limoniastrum monopetalum L. is an interesting small shrub native to Greece and other Mediterranean countries with an attractive foliage, and blooming in the summer with pink flowers. In this work an anatomical and hystochemical study of the species were carried out in order to investigate the suitability of the L. monopetalum for use in urban and suburban areas as ornamental plan and its growth in hostile environments such as archeological sites, roof gardens, landscape restoration (e.g. quarries, roadsides, etc.). The results showed that the leaves of L. monopetalum are amphistomatic bifacial with leaf blade approx. 170 I¼m thick. The epidermal cells is relatively thick approx. 20 I¼m and covered by a 2 I¼m thick cuticle. Furthermore both surfaces of the leaves are entirely covered by salt crystals secreted by the salt glands, as this is revealed from fresh unprocessed specimens observed with the SEM.The histochemical tests showed the presence of terpenoids in the cell walls of the epidermal cells and in the leaf vascular tissues, phenolics, nitrites and alkaloids, flavonoids in the mesophyll cells, especially in the vacuoles, and lipids only in the cuticle. Both morphological anatomical and histochemical characteristics of the leaves indicate the xeromorphic character of the species which render L. monopetalum a suitable plant for ornamental use in a wide spectrum of areas with adverse conditions.

Leaf structure and histochemistry of Ficus carica (Moraceae), the fig tree

Heavily “armed” with trichomes, the hypostomatic leaf of Ficus carica L. is investigated with light and scanning electron microscopy. Histochemical tests were also applied to trace the secondary matabolites produced in the leaf of this well known, Mediterranean tree with the delicious fruits. Numerous idioblasts with crystals, laticifers and sized lythocysts appear within the compact mesophyll. Protective trichomes are located on both surfaces while capitate secretive hairs and stomata appear only abaxially. Stomata, concerning their magnitude, can be assembled in three size-groups in which the arrangement of their parastomatal cells differs as well. Histochemical reactions proved positive only for alkaloids within the laticifers and phenolic compounds, especially for the condensed tannins accumulated within the vacuole of the epidermal cells of this simply constructed leaf with unique features among the Mediterranean herbs. Comparison of GC–MS and LC–HRMS spectra of different extracts of the nerves and, separately, the rest of the leaf, revealed that coumarines such as umbeliferone, psoralen, bergapten and xanthotoxol are probably biosynthetically produced within the nerve area where the highly differentiated, main secretive apparatus of the leaf (laticifers) resides. That is why, these metabolites, are absent from the extracts of the undifferentiated cells derived from in vitro cultures.

Histochemical characterization of secretory ducts and essential oil analysis of Protium species (Burseraceae)

One feature of the Protium genus is the presence of secretory ducts associated with the phloem. These ducts are characterized by the production of essential oils with different classes of secondary metabolites. In light of this observation, the purpose of this study was to determine which secondary metabolites are present in the secretory ducts of P. aracouchini, P. heptaphyllum, P. icicariba and P. warmingianum using histochemical tests and essential oil chemical analysis. The essential oils are present at different levels and compositions in the four studied species; other metabolites also varied from species to species. Variation was observed among the essential oil classes with oxygenated sesquiterpenes being the most representative class found in the species studied. The major component of all species was caryophyllene oxide; thus, it may be regarded as a genus characteristic. Through the results obtained, characteristics common to all species were defined, enabling the segregation of the species and the use of these commonalities in taxonomic studies of the genus.

Sperm storage and morphofunctional bases of the female reproductive tract of the snake Philodryas patagoniensis from southeastern Brazil

Macroscopic and microscopic examination of the female reproductive tract of Philodryas patagoniensis was conducted in order to observe sperm storage structures and determine morphological changes throughout the reproductive cycle. The oviduct of P. patagoniensis is composed of the infundibulum (anterior and posterior), uterus, utero-vaginal junction, and vagina. The uterine epithelium showed constant secretory activity throughout the reproductive cycle, although increased production of secretory granules was observed in secondary vitellogenic females. Sperm storage occurs in the posterior infundibulum and utero-vaginal junction in pregnant, primary (postpartum), and secondary vitellogenic females. These data suggest that P. patagoniensis may be able to produce several clutches from a single mating. Sperm storage in the posterior infundibulum occurs in sperm receptacles, while in the utero-vaginal junction sperm is stored in crypts. Histochemical tests by periodic acid–Schiff revealed that both sperm storage sites increase the production of neutral carbohydrate-rich granules in the presence of sperm, similar to snakes from temperate regions. This is the first report of sperm storage in the posterior infundibulum of a neotropical snake.

Ovary and fruit morphology and anatomy of Amphilophium crucigerum

Amphilophium crucigerum (L.) L.G. Lohmann, known as “pente-de-macaco” is a species of Bignoniaceae native to Brazil, and whose seeds are used in folk medicine. This study aimed to describe morphoanatomical features of this species of fruit to aid in its correct identification and pharmacognostic analysis. Samples of ovary, pericarp and seed were fixed with 3% glutaraldehyde, sectioned on a rotary microtome and analyzed by stereomicroscope. The results are shown in three parts: (1) The ovary presents peltate trichomes, long non-glandular trichomes and emergences in the epidermis; it is 2-carpellate and unilocular with two intruding parietal placenta; ovules are numerous on the placenta; it presents a large quantity of crystals. (2) The pericarp is woody, densely echinate and elliptic shape; it presents a 2-valved capsule and is septicidal; it presents emergences, stomata, lenticels, crystals and a large quantity of clustered stones cells. (3) Seeds are alate, exalbuminate and exotestal; there is a large amount of crystals in the exotestal region; it presents an endothelium and remnant endosperm. Histochemical tests showed the presence of lipophilic substances, polysaccharides, phenolic substances, alkaloids and a small quantity of starch. These pharmacobotanical features described for A. crucigerum are essential for the pharmacognostic analysis of the drug plant.

Roles of mucilage in Emilia fosbergii, a myxocarpic Asteraceae: Efficient seed imbibition and diaspore adhesion.

Several angiosperm families have myxodiaspory, such as the Asteraceae in which cypselae are frequently wind-dispersed. The roles of mucilage in cypselae remain misunderstood, and the route of water uptake from substrate to embryo remains unknown. In this work, we analyze the fruits of Emilia fosbergii aiming to clarify how the water is absorbed and how the structure of the pericarp can be related to the processes of diaspore adhesion and seed imbibition. The anatomy and ultrastructure of the cypselae of Emilia fosbergii were analyzed with histochemical tests and light, scanning and transmission electron microscopy. We assessed the roles of mucilage in seed imbibition using apoplasmic tracing with Lucifer yellow and epifluorescence microscopy and in adhesion with a sand assay. We describe structural and ultrastructural aspects of the exocarpic cells, especially the mucilaginous twin hairs. Lucifer yellow was absorbed only by the twin hairs, the cells where water primarily enters the seed during seed imbibition. In the sand assay, the mucilage was adhesive. The twin hairs on the surface of the cypselae can play a dual role in the establishment of new plants of this species. First, these trichomes constitute the main passage for water intake, which is essential for seed imbibition and germination, and after imbibition, they release mucilage that can adhere the diaspore. Therefore, the presence of myxocarpy in Asteraceae could be important in anemochoric species to avoid secondary dispersal.

Erratum to: Distribution, morphological and histochemical characteristics of foliar trichomes of Plectranthus zuluensis (Lamiaceae)

There are problems in the delimitation/identification of Plectranthus species and this investigation aims to contribute toward solving such problems through structural and histochemical study of the trichomes. Considering the importance of P. zuluensis as restricted to semi-coastal forests of Natal that possess only two fertile stamens not four as the other species of this genus. The objective of this work was to study in detail the distribution, morphology and histochemistry of the foliar trichomes of this species using light and electron microscopy. Distribution and morphology of two types of non-glandular, capitate and peltate glandular trichomes are described on both leaf sides. This study provides a description of the different secretion modes of glandular trichomes. Results of histochemical tests showed a positive reaction to terpenoids, lipids, polysaccharides and phenolics in the glandular trichomes. We demonstrated that the presence, types and structure of glandular and non-glandular trichomes are important systematic criteria for the species delimitation in the genus.

English

The objective of study was to verify if desiccation and storage of the seeds affect the morphoanatomy and histochemistry of the seedlings of Campomanesia adamantium. The fruits were processed and seeds were subjected to desiccation to 30, 20, 15, 10 and 5% water contents in laboratory conditions and subsequently subjected to the following storage conditions: In the laboratory (LAB) (25 ± 2°C, 35% RH), cold and dry chamber (CC) (16 ± 2°C, 40% RH), refrigerator (REF) (8 ± 2°C, 35% RH), and freezer (FZ) (-18 ± 1°C, 42% RH) for 0 (newly processed), 30, 60, 90, 120, 150, and 180 days. The evaluation of the seedling survival rate was performed for 42 days, calculated as the survival percentages for seedling shoot and primary root. Anatomical observations and histochemical tests were performed using fixed and non-fixed samples of the median region of xylopodium in normal and abnormal seedlings. In the morphoanatomy of normal seedlings, we observed cotyledons, hypocotyl, xylopodium, and well defined primary root and in abnormal seedlings, cotyledons, hypocotyl and xylopodium (with 20 and 15% water content), and hypocotyl and primary root (with 10% water content). The desiccation and storage of seeds affected the formation of seedlings by preventing the normal development of roots and shoots. The xylopodium of normal and abnormal seedlings showed positive reaction to starch and lipophilic substances. The presence of phenolic compounds and fructans were observed in parenchyma cells of the xylopodium in abnormal seedlings and absent in normal ones. The deleterious effects of desiccation in association with storage induce the production of phenolic compounds and fructans in abnormal C. adamantium seedlings. Key words: Brazilian Savanna, xylopodium, water content, morphoanatomy, histochemistry.

Colleters in 10 species belonging to three tribes of Rubiaceae: morphoanatomical diversity and potential as useful characters for taxonomy

Colleters are common secretory structures in Rubiaceae. In this study, we describe colleter morphoanatomy and histochemistry in 10 species belonging to Chiococceae, Coussareae, and Psychotrieae tribes of Rubiaceae. Colleter morphoanatomy was analyzed by light and scanning electron microscopy. Microscopy analysis revealed that colleters were present on the stipule adaxial surface in all species. In the case of Palicourea marcgravii A.St.-Hil. and Chiococca alba Hitchc., colleters were also found on leaf primordia and at the stipule apex, respectively. Colleters were classified into three types: standard, bifurcated standard, and reduced standard. Further analysis showed that colleter epidermal cells are thin-walled and possess a thin cuticle, conspicuous nuclei located at the equatorial or basal region, and abundant cytoplasm. Intercellular spaces were found among epidermal cells in Chiococca alba, Coussarea triflora Müll.Arg., Coussarea verticillata Müll.Arg., Psychotria conjungens Müll.Arg., and Psychotria sessilis Vell. Crystalliferous idioblasts containing raphides were observed in the colleter central parenchymatous axis of all species, while crystal sand was found only in Chiococca alba. Histochemical tests revealed that colleter secretion is composed of a mixture of mucilage and protein. We conclude that colleter position, typological variation, presence of vascularization, and type of calcium oxalate crystals represent promising characters for future taxonomic and phylogenetic studies in Rubiaceae.

Determinación histológica de regenerantes de Euchile mariae (Ames) Withner, (Orchidaceae), obtenidos a partir de protocormos cultivados in vitro

From the germination of seeds of Euchile mariae in modified MS medium, the formation of pro- tocorms was achieved. Once these reached an average size from 2 to 5 mm long and the formation of his first leaf primordium, they were used like explants to induce a morphogenetic response. Through in vitro culture of top and bottom protocorms sections, were obtained differentiated structures from asexual origin. Their morphology was similar to protocorms obtained from the germination of seeds, in this way we call them protocorm like bodies (PLB’s). Through of the histological analysis of these structures it was possible to reveal that these PLB’s turned out to be somatic embryos. The histochemical tests demonstrate the pres- ence of cellular contents like: proteins, lipids and starch; both in the cells of the embryos as well as in the cells of initial tissues.

Calicinal trichomes of Adenocalymma magnificum (Bignoniaceae) producing lipophilic substances: ultrastructural and functional aspects

<p class="Normal1">Plant structures that secrete lipids and phenolic compounds are often associated with the protection and development of organs against desiccation, in addition to the protection they provide against animals, as the capitate trichomes of <em>Adenocalymma magnificum</em>. Understanding the glandular activities that occur in these trichomes has required the study of their ontogeny, structure, ultrastructure and histochemical aspects; the interpretation of their ecological functions or evolutionary history is complicated by the scarcity of reports on calicinal trichomes that are not nectar-secreting. Samples of floral calyx in anthesis and flower buds at different stages of development were fixed and processed according to the methods for light and electron microscopy. The trichomes are randomly distributed throughout the entire inner surface of the calyx and are also visible on the flower buds. These capitate glandular trichomes were composed of a peduncle, having up to nine cells, and a multicellular secretory head with their cells in columnar format and arranged in disc form. The collar cell, which is under the secretory head, divides anticlinally and arranges itself side by side with the mother cell. As they develop, they bend with some of them becoming adpressed to the calyx. Histochemical tests indicate that the secretory head cells produce lipid substances, acidic lipids and phenolic compounds. In the secretory head, the vacuome is dispersed and the cytoplasm possesses a great number of smooth endoplasmic reticulum and leucoplasts, organelles involved in the production of osmiophilic substances. In some regions of the secretory cells, cuticle detachment was observed; however, the accumulation of secretions was not observed. This study describes, for the first time, the origin, development, and secretion process of the calicinal trichomes of <em>Adenocalymma magnificum</em>, showing that production of lipophilic substances is important for this plant, possibly the trichomes may be involved in the plant’s chemical defense against insects, offering protection against herbivores.</p>

Histochemical evaluation of induction of somatic embryogenesis in Passiflora edulis Sims (Passifloraceae)

The aim of this study was to describe the accumulation of reserves during the somatic embryogenesis process in Passiflora edulis Sims FB-300, obtained from mature zygotic embryos, using histochemical methods. Mature zygotic embryos were inoculated in Murashige and Skoog induction media supplemented with 31.06 μM of picloram, 2.22 μM of benzyladenine, and 2.27 μM of thidiazuron. The zygotic embryo explants, at different developmental stages, were collected and fixed in Karnovsky solution and subsequently subjected to dehydration in an ethanol series and embedded in acrylic resin. Transverse and longitudinal sections (5-μm thick) were stained with toluidine blue for anatomical characterization, using Xylidine Ponceau for the detection of total protein, periodic acid-Schiff reagent for neutral polysaccharides, Sudan black B to detect lipids, and Lugol’s reagent for the starch detection. Histological sections revealed the formation of protuberances and globular stage somatic embryos in the cotyledonary region of the zygotic embryo. Histochemical tests revealed the presence of large quantities of protein bodies in zygotic embryos of P. edulis, which were gradually metabolized during somatic embryo development. Lipid bodies and starch grains were identified only after 20 d of culture, suggesting the use of these compounds as energy source for de novo synthesis. The present study describes the anatomical changes and the pattern of reserve accumulation during the somatic embryogenesis process in P. edulis.

Location, morphology and function of nephrocytes in termites

Insect nephrocytes are cells bathed in hemolymph and considered to have an excretory function. These cells have ambiguous nomenclature and are understudied in termites. This study is the first report on the occurrence, morphology and function of nephrocytes in different termite castes. Cytological characteristics in specific developmental stages and castes enable physiological functions to be inferred. Perforate diaphragms indicate a role in filtration, while the extensive peripheral invaginations of the cell membrane suggest active endocytosis. A sequence of morphologies in putative digestive vacuoles infers a lysosomal system and the occurrence of phosphatases suggests a function involving detoxification of substances sequestered from hemolymph. Pericardical nephrocytes took up the dye trypan blue injected in live termites, suggesting their activity connected to the filtration of the hemolymph. Additionally, histochemical tests showed the existence of stored proteins in their cytoplasm. These cells present a well-developed Golgi apparatus and abundant rough endoplasmic reticulum, consistent with protein synthesis. This study highlights the importance of nephrocytes in Isoptera and opens perspectives for further research of these cells.

Identification and Screening of Citrus Vein Phloem Degeneration (CVPD) on Brastagi Citrus Variety Brastepu (Citrus nobilis Brastepu) in North Sumatra Indonesia

Identification and screening of Citrus Vein Phloem Degeneration (CVPD) on Brastagi citrus variety Brastepu (Citrus nobilis Brastepu) in North Sumatra Indonesia is explained. The aim of the study is to explore the technique to obtain healthy Brastepu citrus to be used as a source of explants for in vitro propagation as a step in the preservation of threatened local citrus. The studies were conducted through collection of survived Brastepu citrus followed by screening the CVPD in the plants. Various procedures in the field and in the laboratory have been conducted to screen infected CVPD in Brastepu citrus. Visual examination from leaf, fruit, and seed appearance becomes preliminary information for CVPD infection in the citrus plant. Iodine test was used to support results obtained by visual observation. Histochemical test and the PCR analysis have confirmed that 12 samples of Brastepu citrus are free from CVPD and eight citrus are infected by CVPD. Adequate informations have been obtained to confirm healthy citrus tree which are then to be used as sources of explants for in vitro propagation in the preservation of Citrus nobilis Brastepu.

Aspectos biométricos, morfoanatômicos e histoquímicos do pirênio de Bactris maraja (Arecaceae)

Bactris maraja (marajá) é uma palmeira frequente nas margens de lagos e igarapés amazônicos, cujos frutos comestíveis são consumidos pelo homem e pela fauna. Os estudos morfoanatômicos das estruturas reprodutivas podem contribuir com informações que subsidiarão estudos taxonômicos, fisiológicos e ecológicos. O objetivo deste estudo foi determinar características biométricas e morfoanatômicas do pirênio, bem como características histoquímicas da semente. Frutos maduros foram coletados e foram determinadas as dimensões, a massa fresca, e o teor de água, e descritas a forma, coloração e textura. O estudo anatômico foi feito pelo método de inclusão em resina. Foram aplicados testes histoquímicos para detecção dos principais metabólitos. Tanto os pirênios quanto as sementes isoladas apresentaram pequena variação biométrica, exceto para a massa fresca. O pirênio varia de obovado a elíptico, com endocarpo espesso, rígido, formado por células esclerificadas de paredes espessas. A semente é obovada depressa a elíptica, com tegumento fino, cartáceo, marrom-claro, aderido ao endocarpo, constituído de células parenquimáticas espessadas e taníferas; endosperma volumoso, sólido, homogêneo, branco, formado por células oblongas, elípticas e ovais transversalmente, e arredondadas longitudinalmente, com reserva proteica e lipídica; embrião lateral, cônico, pequeno, branco-leitoso, com conteúdo proteico e lipídico, polo radicular indiferenciado e polo caulinar com três primórdios foliares.

A Rapid and Efficient Protocol for Clonal Propagation of Phenolic-Rich Lavandula multifida

Lavandula multifida (fernleaf lavender) grows in confined regions of Portugal. This species is known for its interesting chemical profile, rich in phenolic compounds, and significant antifungal and anti-inflammatory properties, making it an interesting plant for industrial exploitation and justifying alternative propagation methods. Therefore, the present study aims the development of an efficient protocol for large scale propagation of this species, assuring plant uniformity and aiming a sustainable industrial exploitation with preservation of natural resources. In vitro cultures were established on Murashige and Skoog medium (MS) with different concentrations of benzyladenine (BA) and zeatin (ZEA). Best multiplication rates (6.14 shoots per explant) were achieved using MS supplemented with 1.0 mg/L ZEA and rooting occurred spontaneously on the propagation medium avoiding additional rooting steps. Moreover, plants flowered during the acclimatization phase, confirming a more rapid in vitro development and shorter breeding cycle. This is a very interesting aspect for essential oil extraction. Trichome morphology was examined by scanning electron microscopy and the secretion analyzed through histochemical tests. Trichomes of micropropagated plantlets were identical to those of field-growing plants, and essential oil production was observed at early stages of development. The present study confirms that micropropagation under controlled conditions could be an interesting alternative for field production of L. multifida, since higher amounts of plants can be obtained in less time with guarantee of genetic stability and phytossanitary quality, very important features regarding essential oil production and commercialization.

Effect of pollution by particulate iron on the morphoanatomy, histochemistry, and bioaccumulation of three mangrove plant species in Brazil

In Brazil, some mangrove areas are subjected to air pollution by particulate iron from mining activities. However, the effect of this pollutant on mangrove plants is not well known. This study aimed to comparatively analyze the morphoanatomy, histochemistry, and iron accumulation in leaves of Avicennia schaueriana, Laguncularia racemosa, and Rhizophora mangle. Samples were collected from five mangrove sites of Espírito Santo state, each of which is exposed to different levels of particulate iron pollution. The amount of particulate material settled on the leaf surface was greater in A. schaueriana and L. racemosa, which contain salt glands. High iron concentrations were found in leaves of this species, collected from mangrove areas with high particulate iron pollution, which suggests the foliar absorption of this element. None of the samples from any of the sites showed morphological or structural damage on the leaves. Scanning electron microscopy (SEM) coupled to X-ray diffraction rendered a good method for evaluating iron on leaves surfaces. A histochemical test using Prussian blue showed to be an appropriate method to detect iron in plant tissue, however, proved to be an unsuitable method for the assessment of the iron bioaccumulation in leaves of A. schaueriana and R. mangle. So far, this study demonstrates the need of evaluating the pathway used by plants exposed to contaminated particulate matter to uptake atmospheric pollutants.

Trichomes related to an unusual method of water retention and protection of the stem apex in an arid zone perennial species.

It is well known that trichomes protect plant organs, and several studies have investigated their role in the adaptation of plants to harsh environments. Recent studies have shown that the production of hydrophilic substances by glandular trichomes and the deposition of this secretion on young organs may facilitate water retention, thus preventing desiccation and favouring organ growth until the plant develops other protective mechanisms. Lychnophora diamantinana is a species endemic to the Brazilian 'campos rupestres' (rocky fields), a region characterized by intense solar radiation and water deficits. This study sought to investigate trichomes and the origin of the substances observed on the stem apices of L. diamantinana. Samples of stem apices, young and expanded leaves were studied using standard techniques, including light microscopy and scanning and transmission electron microscopy. Histochemical tests were used to identify the major groups of metabolites present in the trichomes and the hyaline material deposited on the apices. Non-glandular trichomes and glandular trichomes were observed. The material deposited on the stem apices was hyaline, highly hydrophilic and viscous. This hyaline material primarily consists of carbohydrates that result from the partial degradation of the cell wall of uniseriate trichomes. This degradation occurs at the same time that glandular trichomes secrete terpenoids, phenolic compounds and proteins. These results suggest that the non-glandular trichomes on the leaves of L. diamantinana help protect the young organ, particularly against desiccation, by deposition of highly hydrated substances on the apices. Furthermore, the secretion of glandular trichomes probably repels herbivore and pathogen attacks.

Colleters on the Inflorescence Axis ofCroton glandulosus(Euphorbiaceae): Structural and Functional Characterization

Premise of research. Croton glandulosus L. is a ruderal annual species of Euphorbiaceae native to the American tropics and widespread in urban and rural areas in Brazil. We investigated the structure, histochemistry, and ultrastructure of glands on the inflorescence axis of C. glandulosus to explore the relationship between their structure and function.Methodology. Reproductive apexes were prepared according to standard methods for plant anatomy, SEM, and TEM. Histochemical tests were performed using fresh material.Pivotal results. Mature glands are bowling pin shaped and are differentiated into a single-layered secretory epidermis arranged radially around a parenchymatous central axis supplied with xylem. In the neck region of the glands, the epidermal cells present structural components typical of lipophilic secretion, whereas the parenchyma cells are specialized in the production of hydrophilic compounds. The resinous secretion is released by cuticle pores occurring exclusively on the tip of the gland....