Histochemical Tests Research Articles

Signet Ring Stromal Cell Tumor: A Legitimate (Benign) Mimic of Krukenberg Tumor.

Signet ring stromal cell tumor is a rare, benign ovarian neoplasm thought to arise from ovarian stromal cells. The pathophysiology of these tumors is poorly understood. They present in women in a wide age range, often with nonspecific symptoms including lower abdominal or pelvic pain. Their morphologic appearance raises a critical differential diagnosis of Krukenberg tumor, an aggressive malignancy with significant implications for patient management. For this reason, it is important for the pathologist to be aware of signet ring stromal cell tumor and its differentiating features, including useful histochemical and immunohistochemical ancillary tests. These tumors are curable with surgical excision, and there have been no recurrences or metastases among reported cases.

Effect of Simvastatin on Male Albino Rats, Cytogenetic and Histochemical Studies

Simvastatin belongs to statins drugs that are used globally for lowering blood cholesterol level in cardiovascular patients. Simvastatin can be considered as life threatening agent, since prolonged usage may cause myotoxicity. Materials & methods: The present study was performed on 20 adult male rats which were divided into: Group I which was the control group that did not receive any treatments, and Group II which was the treated group that received 80 mg/kg b.wt/day of simvastatin for 46 days. All rats were submitted to bone marrow collection for the cytogenetics tests and gastrocnemoius muscles’ biopsied were taken for the histochemical tests. Results: statistical analysis showed a non-significant increase in the mean of chromosomal aberrations (CAs) in the treated rats’ cells comparing to the control samples. On the other hand, an observed non-significant decrease in the mean of total proteins (TP) content in rats’ gastrocnemius muscles of Group II when compared to the control group. Whereas, noticed significant reduction in the mean of glycogen (Glyc.) content in rats’ gastrocnemius muscles of the same group when compared to the control group. Conclusion: Simvastatin may lead to an increase in the incidence of (CAs) in bone marrow cells, and determination of TP and Glyc. content in skeletal muscle biopsies can be considered as indicators for muscle necrosis incidence. Recommendations: Simvastatin has to be prescribed carefully in patients suffering from hypercholesterolemia, precautions have to be taken into consideration since it may affect skeletal muscles’ health and lead to muscle toxicity on the short or long run of usage.

In depth investigation of the metabolism of Nectandra megapotamica chemotypes.

Plants produce a wide range of secondary metabolites. Within a single species, chemotypes can be distinguished by the differences in the composition of the secondary metabolites. Herein, we evaluated Nectandra megapotamica (Spreng.) chemotypes and the balance of different classes of metabolites to verify how significant differences in plant metabolism are regarding chemotypes. We collected N. megapotamica leaves from eight adult plants in two Brazilian states. The essential oils and ethanol/water extracts were analyzed by GC-MS and LC-DAD-MS, respectively. Histochemical tests were performed, as well as chemical analyses of leaves from adaxial and abaxial foliar surfaces of N. megapotamica, and the stereochemistry of α-bisabolol was determined. Two different chemotypes, based on volatile compounds, were identified, distinguished by the presence of isospathulenol, α-bisabolol, β-bisabolene, and (E)-nerolidol for chemotype A, and bicyclogermacrene and elemicin for chemotype B. A stereochemical analysis of chemotype A extract revealed (+)-α-bisabolol enantiomer. Histochemical tests of chemotypes showed similar results and suggested the presence of essential oil in idioblasts stained with the dye NADI. The analyses of chemotype A leaves by GC-MS revealed similar compositions for abaxial and adaxial surfaces, such pattern was also observed for chemotype B. Medium and high polarity metabolites showed high chemical similarities between the chemotypes, highlighting the presence of proanthocyanidins and glycosylated flavonoids (O- and C-glycosides). Thus, N. megapotamica produced distinct volatile chemotypes with highly conserved medium to high polarity compounds. Such results suggest that phenolic derivatives have a basal physiological function, while genetic or environmental differences lead to differentiation in volatile profiles of N. megapotamica.

Anatomical, phytochemical and histochemical study of Solidago chilensis Meyen.

Solidago chilensis Meyen, belonging to the family Asteraceae, is a plant native to South America and the only representative of the genus in Brazil. This species is popularly known as "arnica" and is used to treat bruises, muscle pain and inflammation. The objective of this work was to contribute to the pharmacognostic standardization of S. chilensis. Cross-sections were obtained, by freehand, for microscopic analysis of root, stem and leaf; for these parts of the plant maceration was also performed according to the method of Jeffrey. For the leaf were still made paradermal sections, scanning electron microscopy analysis, phytochemical and histochemical tests. Thus, it was determined anatomical features useful for diagnosis of the species which, together with identification of the chemical compounds and its histolocalization, provides support to their quality control.

Morphology and Histochemistry of the Venom Apparatus in Different Castes of the Ant Ectatomma vizottoi (Formicidae: Ectatomminae)

The elimination of toxins via a venom gland by some ant species is a component of a larger mechanism for capturing prey and defense. The present study describes the morphology and histochemistry of the venom apparatus of different castes of the ant Ectatomma vizottoi Almeida, 1987. Morphologically, the venom apparatus of queens, gynes and workers of E. vizottoi are similar and composed of the sting apparatus and three distinct portions: two secretory portions (convoluted gland and secretory filament), and a storage portion (reservoir) - a hollow sting apparatus covered in the terminal portion of the reservoir by a sclerotized cuticle. The venom gland of E. vizottoi is longer in queens and gynes than in workers. Furthermore, the epithelium of the convoluted gland is taller in the glands of queens and gynes than in workers, which may be indicative of greater toxin synthesis, or may be related to different body sizes of the castes. The morphology and histology of the venom apparatus reflect those of a generalist, while the histochemical tests indicated that this structure has the same chemical content of lipids, proteins and polysaccharides among queens, gynes, and workers. Images obtained by confocal microscopy and scanning electronic microscopy reveal a muscle layer surrounding the reservoir that is interlaced with secretory filaments, which fixes, in a manner, the filaments in place. This musculature serves to eject stored venom, which likely leads to greater success in defense or foraging.

Morpho–anatomical and ultrastructural analysis of extrafloral nectaries in Inga edulis (Vell.) Mart. (Leguminosae)

The presence of extrafloral nectaries (EFNs) between leaflets is an usual feature in Inga edulis (Vell.) Mart. (Leguminosae). Extrafloral nectaries are secretory structures involved in production of nectar and which serve in the protection of plants against herbivores through association with ants. This study aimed to characterize the EFNs of I. edulis at different developmental stages and describe their morphology, histochemistry and ultrastructure. Leaf fragments, containing secretory structures, were processed according to standard methods for light, scanning and transmission electron microscopy. The EFNs were classified into three stages based on morphology: pre‐secretory, secretory and post‐secretory. The pre‐secretory stage occurs in young leaves, whereas secretory and post‐secretory stages occur in developed and senescent leaves, respectively. The EFNs possess a concave surface and a central cleft in which nectar is accumulated and which was not observed in pre‐secretory EFNs. Histochemical tests identified the presence of sugars, proteins, phenolic compounds, mucilage and lipids at all developmental stages of the EFNs. Calcium crystals were identified in all tissues and stages of the EFNs. The secretory cells of the EFNs exhibit a granular cytoplasm, small vacuoles, prominent nuclei, smooth endoplasmic reticulum and mitochondria. Post‐secretory stage EFNs exhibited intense cytoplasmic degradation and the presence of microorganisms. The performance of EFNs of I. edulis appear to follow the leaf development.

AN APPROACH ON ANATOMICAL STRUCTURE OF CHAETOSTOMA GLAZIOVII COGN – MELASTOMATACEAE – AND ITS SUCCESSFUL ESTABLISHMENT AT HIGH-ALTITUDE FIELDS

Chaetostoma glaziovii Cogn. is an endemic species of the Brazilian flora and grows exclusively in fields at elevations above 2000 meters. It belongs to Melastomataceae family, Microlicieae tribe, which presents little variation on vegetative organs, making it difficult to identify sterile individuals. Anatomical studies, using optical and scanning electron microscopes are carried on comparing the data with the anatomical characteristics of xeromorphic plants, cited in the literature, to check its similarities. This study aims, also, highlight data that may contribute to characterization of the species due to the great similarities among sterile individuals within the tribe. Leaf and stem anatomical data of C. glaziovii are interpreted considering climatic factors, aiming to understand the species’ successful establishment in an environment characterized by intense light exposure, strong winds and extreme temperatures. It is noteworthy the great amount of fibers on the abaxial and marginal regions of leaf blade, forming an armor against environmental aggressions. In addition, this characteristic is valued from the taxonomic perspective because no other species of the tribe exhibits such extensive fiber development. The material was collected in the Itatiaia National Park at an altitude of 2350 meters, latitude S 22° 23' 26'' and longitude W 44o 40' 17''. Histochemical tests were performed on unfixed samples to identify starch grains, lipids, phenolic compounds, glycides and crystals. The anatomical data revealed that some characteristics of C. glaziovii are like those found on xeromorphic plants and are important for its identification beyond to contribute for understanding the intricate plant-environment relationships.

Micromorphological and histochemical attributes of flowers and floral reward in Linaria vulgaris (Plantaginaceae)

The self-incompatible flowers of Linaria vulgaris have developed a range of mechanisms for attraction of insect visitors/pollinators and deterrence of ineffective pollinators and herbivores. These adaptive traits include the flower size and symmetry, the presence of a spur as a “secondary nectar presenter,” olfactory (secondary metabolites) and sensual (scent, flower color, nectar guide—contrasting palate) signals, and floral rewards, i.e. pollen and nectar. Histochemical tests revealed that the floral glandular trichomes produced essential oils and flavonoids, and pollen grains contained flavonoids, terpenoids, and steroids, which play a role of olfactory attractants/repellents. The nectary gland is disc-shaped and located at the base of the ovary. Nectar is secreted through numerous modified stomata. Nectar secretion began in the bud stage and lasted to the end of anthesis. The amount of produced nectar depended on the flower age and ranged from 0.21 to 3.95 mg/flower (mean = 1.51 mg). The concentration of sugars in the nectar reached up to 57.0%. Both the nectar amount and sugar concentration demonstrated a significant year and population effect. Pollen production was variable between the years of the study. On average, a single flower of L. vulgaris produced 0.31 mg of pollen. The spectrum of insect visitors in the flowers of L. vulgaris differed significantly between populations. In the urban site, Bombus terrestris and Apis mellifera were the most common visitors, while a considerable number of visits of wasps and syrphid flies were noted in the rural site.

Structural and histochemical profile of Lopesia sp. Rübsaamen 1908 pinnula galls on Mimosa tenuiflora (Willd.) Poir. in a Caatinga environment

ABSTRACT Gall-inducing insects can change the anatomical pattern of host plant tissues by inducing peculiar gall morphotypes. In this study, the structural changes observed in Lopesia galls on Mimosa tenuiflora resemble those found in other Cecidomyiidae, with two tissue compartments. Nevertheless, the parenchyma layers of the inner compartment, between the mechanical zone and the nutritive tissue, are peculiar. Gall development does not impair the synthesis of any compounds detected by histochemical tests on non-galled tissues of M. tenuiflora. Lignin, polyphenols, alkaloids and terpenoids were detected in the outer compartment, suggesting their involvement in chemical defence of galls. Proteins, reducing sugars and lipids were detected both in outer and inner compartments, whereas nutritive tissue is rich in reducing sugar. This profile is linked with the nutrition of the gall-inducing insect. The Caatinga environment does not seem to constrain the development of galls, but the thick periclinal cell wall and homogeneous parenchyma may contribute to the control of humidity and light radiation, thus favouring the survival of the gall-inducing insect.

Diversity of floral nectary secretions and structure, and implications for their evolution in Anacardiaceae

The flowers of most Anacardiaceae have a floral nectary disk producing nectar rich in sugars. However, a recent study demonstrated that their nectaries might also produce other substances, including lipids and phenolic compounds. To explore the diversity of floral nectary production and (ultra)structure, and their potential for the systematics of Anacardiaceae, we studied seven genera and 13 species from the two subfamilies. We used spectrophotometry to identify sugars and histochemical tests for other substances, and electron and brightfield microscopy to study nectary (ultra)structure and secretory pathways. The composition of sugars and other substances can vary between closely related species and be more similar in species from different subfamilies, being of limited value for the systematics of the family. The general morphology and structure of the floral nectary and their secretory pathways appear to be conservative in the family, and, like the production of mixed secretions, they might be plesiomorphic. Three morphological types of floral nectaries are defined for the family: nectariferous disk with papillose (1) or smooth epidermis-type (2) and trichomatous-type (3). The secretions may be released both by granulocrine and eccrine mechanisms and exuded through nectarostomata or the cuticle. Further studies are needed to better understand their evolutionary and ecological implications in Anacardiaceae and other sapindalean lineages.

Silicon (Si) Supplementation Alleviates NaCl Toxicity in Mung Bean [Vigna radiata (L.) Wilczek] Through the Modifications of Physio-biochemical Attributes and Key Antioxidant Enzymes

Mung bean is an important pulse crop. It is highly nutritive but is vulnerable to salinity stress. Therefore, the present study was aimed to investigate the protective effect of silicon (Si) against salt stress-induced damage to mung bean plants. Mung bean plants treated with NaCl (0, 50 and 100 mM) showed considerable declines in length and dry weights of shoots and roots. Chlorophyll-a (chl-a), chl-b, total chl, carotenoids and leaf relative water content (LRWC) decreased under NaCl stress. However, supplementation with Si in the form of sodium silicate (Na2SiO3) to NaCl-stressed plants ameliorated the adverse effects of NaCl on growth, biomass, pigment synthesis and leaf relative water content (LRWC). Silicon (Si)-supplemented plants exhibited enhanced chl-fluorescence and gas exchange parameters under normal (non-stress) as well as NaCl stress conditions. Salt-induced decline in the frequency of stomata and number of leaves per plant under salt stress was significantly recovered with Si supplementation. In addition, application of Si increased the levels of proline and glycine betaine in mung bean plants. Furthermore, histochemical staining tests showed that the levels of superoxide radicals and H2O2 increased with NaCl treatments, which thereby resulted in increased lipid peroxidation (LPO) and electrolyte leakage. Contrarily, decreased levels of H2O2, lipid peroxidation (measured as MDA content), and electrolyte leakage in Si-supplemented plants under NaCl stress indicated the stress mitigating role of Si. The activities of key antioxidant enzymes (SOD, CAT, APX and GR) under NaCl stress showed an increase under the NaCl regime. However, application of Si further boosted the activities of all four antioxidant enzymes in NaCl-stressed plants. The enhanced Na+ uptake and Na+/K+ ratio in mung bean plants accompanied by decreased K+ and Ca2+ uptake under NaCl stress were reversed with Si supplementation thereby resulting in enhanced accumulation of K+ and Ca2+ and decreased Na+. In conclusion, Si supplementation mitigated the negative effects of NaCl on mung bean plants through modifications in uptake of inorganic nutrients, osmolyte production and the antioxidant defence system.

Functional anatomy reveals secretory activity in papillose anthers of a buzz-pollinated Solanum species (Cyphomandra clade - Solanaceae).

Pollination in Solanum (Solanaceae) species is commonly performed by female bees, which vibrate anthers to extract pollen. Another pollen removal type is by male euglossine bees, milking the anthers when searching for floral scents produced by secretory tissues (osmophorous) at the swollen connective of the anthers of species in the Cyphomandra clade. Some species of this clade, however, are buzz-pollinated and present papillate anthers that should also have secretory activity, a hypothesis here tested. The anthers of Solanum luridifuscescens were fixed at different stages of development and analysed under light microscopy, SEM and TEM. Histochemical tests for the detection of starch and lipids were done. Epidermal cells of the abaxial surface of the anthers were visibly papillose, had large nuclei and dense cytoplasm rich in organelles such as mitochondria and plastids, typical features of secretory tissues. In this site, lipid droplets were detected, concomitantly with starch consumption, compatible with the secretory process in osmophores. No exudate or accumulation of substances was seen on the surface; in agreement with a previous pollination study performed in field conditions, where no pollinators were observed collecting floral scents, only pollen. The histochemical and structural analyses have evidenced the lipidic composition of the secretion, strongly pointing to terpenes as the secreted compounds. Ours findings show that papillae of the anthers have secretory activities that produce lipophilic compounds. This does not result in resources for bees, but could be an evolutionary step to the development of more specialised anthers in the Cyphomandra clade.

Leaf essential oils and volatiles, histochemistry and micromorphology of Neomitranthes obscura (DC.) N. Silveira (Myrtaceae) growing in sandy coastal plains of Rio de Janeiro

We evaluated the chemical composition of leaf essential oils and volatiles in Neomitranthes obscura from different sandy coastal plains in Rio de Janeiro State. These sites present different environmental conditions. Leaf essential oils and volatiles were characterized by GC/MS after simultaneous distillation-extraction (SDE) and hydrodistillation (HD). All samples were rich in sesquiterpenes, mainly those from cadinene, germacrene and caryophyllene cyclization pathways, including (E)-caryophyllene, α-copaene, β-selinene, α-cadinene, selina-3,7 (11)-diene, germacrene B and caryophyllene oxide. Chemical profiles of N. obscura from different restingas presented high variation in the relative amount of some compounds. Fewer compounds were produced in a semi-arid climate (Massambaba restinga). Comparing samples collected during different seasons in Marambaia restinga, (E)-caryophyllene presented highly variable concentrations. The highest concentration was observed in August, which is the month of least rainfall. In contrast, germacrene B presented the lowest concentration in August. Leaf secretory structures were described using light and scanning microscopy and histochemical tests. The main sites of lipophilic and terpenoid accumulation are located in the secretory cavities of mesophyll. Our data indicate that the production of essential oils and volatiles in N. obscura is influenced by both plant developmental stage and environmental conditions.

Morphological and Physiological Germination Aspects of Anadenanthera colubrina (Vell.) Brenan

Anadenanthera colubrina is a species native to Brazil, from the Fabaceae family and has potential for use in the timber industry, in the reforestation of degraded areas, besides having medicinal properties. Its propagation is mainly by seeds, but basic subsidies regarding the requirements for optimal germination conditions are still lacking. Aiming to contribute to the expansion of its cultivation, rational use and conservation, the objective of this study was to investigate the morphology and anatomy of fruits and seeds, as well as the responses to factors as thermal regimes and substrates in seed germination. The 1000-seed weight and seeds per fruit were determined. To characterize the seed tissues, histochemical test with Sudan III and Lugol was used. The temperatures analyzed in the germination test were 15-25 °C; 25 °C; 20-30 °C and 30 °C. Different substrates for germination (paper rolls, paper sheet such as “germitest”, commercial substrate and sand) were also analyzed in the presence of light at 30 °C. The average number of seeds per fruit is 10 and the 1000-seed weight is 118 g. Germination is fast and high over a wide temperature range; however, the temperature of 25 °C contributes to a substantial increase in the percentage of abnormal seedlings and dead seeds, both in the absence and presence of light. A. colubrina seeds are indifferent to light and the highest vigor was verified at 30 °C. Sand and commercial substrates are efficient in initial seedling development.

Is scleromyxedema a skin problem or systemic pathological process?

Scleromyxedema is regarded as a rare cutaneous mucinosis from a group of lichen myxedematosus characterized by diffuse mucin deposition, sclerosis, and lichenoid eruptions in the absence of thyroid disease. The paper discusses the pathogenesis of the disease and histological changes in tissues. It underlines the need for using histochemical tests to identify acidic and neutral glycosaminoglycans and gives a differential diagnosis of this disease.

MORPHOANATOMY OF Garcinia madruno (KUNTH) HAMMEL (CLUSIACEAE) UNDER WATERLOGGED CONDITIONS

ABSTRACT Garcinia madruno (Kunth) Hammel is a neotropical tree that naturally occurs in terra firme forests and is important as a source of income and medicine for Amazonian populations. This study describes and compares the morphoanatomical responses of plants under conditions of stress and normoxia. Young plants of Garcinia madruno were subjected to two water regimes: daily controlled irrigation and waterlogged for 84 days. Hypertrophic lenticels, adventitious roots and anatomical characteristics of the roots and leaves were evaluated on days 0, 21, 42, 63 and 84. There were no changes in leaf structure, but cracks and hypertrophic lenticels appeared on the stems, there was an increase in blackness of the roots and the plants formed adventitious roots to adapt to the flooded environment. The anatomical changes in the roots of the flooded plants were thickening of the exodermis in the main root and of the pericycle in the lateral roots, and a large increase in the amount of aerenchyma. Histochemical tests detected starch in the midrib, mesophyll, stem and root of flooded plants, and in the petiole of control plants. In the waterlogged plants, phenolic compounds were found in the petiole and alkaloids were found in the midrib, petiole and root.

Pollen morphology and viability in Bromeliaceae.

Pollen morphology characterization is important in taxonomy, conservation and plant breeding, and pollen viability studies can support breeding programs. This study investigated pollen morphology and male fertility in 18 species of Bromeliaceae with ornamental potential. For morphological characterization, pollen grains were acetolyzed and characterization of exine was done using scanning and transmission electron microscopy. Pollen viability was investigated by in vitro germination and histochemical tests. Species belonging to Aechmea and Ananas genera presented medium size pollen, except for Ae. fasciata, with large pollen. Al. nahoumii, P. sagenarius and the Vriesea species analyzed showed large pollen, except for V. carinata, with very large pollen. Pollen of Aechmea, Ananas and P. sagenarius presented bilateral symmetry, diporate, exine varying from tectate to semitectate. Al. nahoumii and Vriesea species presented pollen with bilateral symmetry, monocolpate; exine was semitectate, reticulate and heterobrochate. Germination percentage and tube growth were greater in SM and BKM media. Histochemical tests showed pollen viability above 70% for all species, except for Ananas sp. (40%). Pollen morphology is important for the identification of species, especially in this family, which contains a large number of species. High rates of viability favor fertilization and seed production, essential for efficient hybrid production and conservation.

Anatomía e histoquímica de los órganos subterráneos de plantas trepadoras medicinales rioplatenses (Argentina)

Fil: Colares, Marta Noemi. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentina. Universidad de Belgrano. Facultad de Ciencias Exactas y Naturales; Argentina

Floral and reproductive biology of Alcantarea nahoumii (Bromeliaceae), a vulnerable endemic species of the Atlantic Forest

Alcantarea nahoumii occurs exclusively in the state of Bahia, Brazil, and is classified as vulnerable due to deforestation and frequent fires in the region. Knowledge of floral and reproductive biology is fundamental to understanding ecological interactions, as well as the reproductive success of plant species. The objective of this study was to evaluate the floral and reproductive biology of A. nahoumii in an Atlantic Forest fragment with regard to phenology, pollen viability, stigma receptivity, pollination ecology and reproductive systems, all of which are important parameters for of the development of conservation strategies for the species. Anthesis is diurnal and heterogeneous, starting at 6:30 a.m. and lasting until 8:00 a.m. Highest germination percentages and greatest pollen tube lengths were obtained in BK culture medium. Histochemical tests revealed high pollen viability (89.71 %). Stigma receptivity occurred during anthesis and lasted for up to 24 hours after floral opening. Alcantarea nahoumii exhibited preferential allogamy and self-compatibility, and required a pollinator to production of viable seeds. Sixteen species of pollinators were observed visiting A. nahoumii, among which were five hummingbird species. Even though its reproductive system is efficient, this bromeliad remains threatened mainly due to habitat fragmentation caused by deforestation, burning and predatory extractivism.

Histological and histochemical characterization of leaves and petals of the endangered native Brazilian species Hesperozygis ringens (Benth.) Epling

Hesperozygis ringens (Benth.) Epling is an endangered Lamiaceae woody herb characterized by the abundance of essential oil (EO) in its leaves. However, no information has been found in literature about the plant tissues where this extractive is biosynthesized, and what other constituents are produced by the organ. In addition, the classes of compounds biosynthesized by its petals and the composition of EO produced by the inflorescences have not been reported either. Because this information may help the H. ringens identification, the aim of this study was to characterize the compound classes in the plant leaf and petal by histochemical tests. The leaves and flowers of this species were collected from a population in Santo Antão, municipality of Santa Maria, Rio Grande do Sul, Brazil. Fresh plant material was analyzed to detect total lipids; acid and neutral lipids; essential oils (EOs), resins and oil-resins; proteins; starch; phenolic compounds; tannins; flavonoids; and alkaloids. The EOs of leaves and inflorescences were extracted by hydrodistillation and their chemical compositions were analyzed by gas chromatography coupled to mass spectrometry (GC–MS) and GC with flame ionization detector.Results obtained in histochemical tests detected total, neutral and acid lipids, EOs, oil-resins, protein, phenolic compounds, flavonoids and alkaloids in the leaves and petals of H. ringens. Total lipids were found mainly in leaf mesophyll and glandular trichomes of both plant organs. Essential oils were marked in leaf vascular bundle, petal surface and glandular trichomes of both fresh organs. Oil-resins were detected mainly in leaf mesophylls and petal glandular trichomes. The chemical characterization of the EOs produced by leaves and inflorescences detected the oxygenated monoterpenoid pulegone as their major compound. The species presented histochemical characteristics which have not been found for other Lamiaceae representatives yet, and may serve to identify H. ringens.