Secretory Idioblasts Research Articles

Oil and mucilage idioblasts co-occur in the vegetative organs of Ocotea pulchella (Lauraceae): comparative development, ultrastructure and secretions.

This study compares oil and mucilage idioblasts occurring together in the vegetative organs of Ocotea pulchella, a Lauraceae species. Our focus is specifically on the ontogeny and developmental cytology of these secretory cells. Both types of idioblasts originate from solitary cells located in the fundamental meristem, underlying the protodermis. The growth of both types of idioblasts is asynchronous, with the oil idioblasts developing first, but their initiation is restricted to the early stages of organ development. Mucilaginous idioblasts occur exclusively in the palisade parenchyma, while oil idioblasts are scattered throughout the mesophyll, midrib, and petiole of the leaves. The lamellar secretion of mucilage idioblasts is mostly made up of polysaccharides, while the secretion of oil idioblasts is made up of terpenes and lipids. Cupule occurred only in the oil idioblasts, while suberized layers occurred in both types of cells. We found that immature oil idioblasts that are close to each other fuse; mature mucilage idioblasts have labyrinthine walls arranged in a reticulate pattern; the cells close to the oil idioblasts have a pectin protective layer; and the oil idioblasts have a sheath of phenolic cells. In contrast to previous reports, the two types of secretory idioblasts were recognized during the early stages of their development. The results emphasize the importance of combining optical and electron microscopy methods to observe the ontogenetic, histochemical and ultrastructural changes that occur during the development of the secretory idioblasts. This can help us understand how secreting cells store their secretions and how their walls become specialized.

New Information of the Anatomy and Phytochemical Screening of Pentaclethra macroloba (Willd.) Kuntze (Caesalpinioideae-Leguminosae) Seeds

Pentaclethra macroloba (Willd.), whose common name is “pracaxi,” is naturally found in the Amazon region. The present study is aimed at analyzing the anatomy, seed histochemistry, and chemical composition in fatty acid profile of P. macroloba seed oils. Seeds were collected in the cities of Belém, Marituba, and São Domingos do Capim-PA. For the study in light microscopy, scanning electron microscopy, and histochemistry, seeds were sectioned in cross and longitudinal sections of the embryonic axis and fixed in formaldehyde, acetic acid, and 50% ethyl alcohol; neutral-buffered formalin; and formaldehyde and ferrous sulfate and stored in 70% ethyl alcohol. For the anatomical study, the seeds were subjected to the usual techniques of plant anatomy. Histochemical tests were performed on plant material, freehand sectioned, and embedded in histological paraffin with DMSO. The fatty acid profile was determined for gas chromatography (GC-FID). Integument is divided into three strata, monoseriate exotesta, mesotesta formed by several layers of parenchyma cells, and monoseriate endotesta, formed by compressed cells. Cotyledons are composed of thin-walled parenchyma cells with several secretory cavities and secretory idioblasts. The main metabolic classes are lipids, phenolic compounds, carbohydrates, proteins, and alkaloids. The main fatty acids found in P. macroloba oil are oleic, behenic, lignoceric, and linoleic. P. macroloba seeds have important anatomical characteristics for their circumscription in Leguminosae and also in Caesalpinioideae, and their oil is rich in fatty acids essential to the human diet, providing many benefits to the human health, such as fatty acids belonging to the omega family (linoleic, oleic).

Risk of Poisoning from Garden Plants: Misidentification between Laurel and Cherry Laurel.

The misidentification between edible and poisonous plants is an increasing problem because of the new trend to collect wild plants, especially by amateur collectors who do not have the botanical skills to distinguish between edible and toxic species. Moreover, morphologically similar species are sometimes responsible for accidental contamination or used in the intentional adulteration of products for human and animal consumption. Laurus nobilis L. (laurel) and Prunus laurocerasus L. (cherry laurel) are typical ornamental shrubs of the Mediterranean region. Laurel is considered a non-toxic plant, widely used as flavorings. Conversely, cherry laurel leaves, morphologically similar to those of laurel, contain toxic cyanogenic glycosides. Considering this, the aim of this study was to carry out an in-depth evaluation of laurel and cherry laurel leaves by using light and scanning electron microscopy coupled with three step phytochemical analyses (qualitative and quantitative colorimetric assays and liquid chromatography). This allowed to highlight the distinguishing features of plant species investigated features such as the venation pattern, presence/absence of nectaries, calcium oxalate crystals, secretory idioblasts, and cyanogenic glycosides. Concluding, this multidisciplinary approach can be useful for the identification of plants but also fragments or pruning residues containing cyanogenic glycosides, in quality control tests, intoxications, and criminal cases.

The Amazonian Croton mollis (Euphorbiaceae): morphology and leaf anatomy help to understand its preference for the extreme igapó habitat

Identifying traits contributing to the success of organisms living in harsh environments has always been of great interest in evolutionary ecology. Here we focused on morphological features that could be advantageous for the survival of Croton mollis, a slender shrub occurring in the extreme white-sand habitats of the Amazonian igapos (black/clear-water rivers). We examined macro-morphological characters, as well as leaf micro-morphology using light microscopy and scanning electron microscopy. We also estimated areas of habitat suitability for C. mollis based on climatic, soil, and elevation variables using species distribution modelling (SDM) and available herbarium collections. Our results show that C. mollis presents morphological attributes similar to those of rheophytes, which may allow the species to overcome drastic seasonal changes in water level. We report the presence of five secretory structures (extrafloral nectaries, colleters, idioblasts, glandular trichomes, and laticifers) in the leaves. The size and position of the secretory idioblasts support the hypothesis of the existence of a transitional storage for secondary metabolites from idioblasts to secretory trichomes. Besides glandular trichomes, we also found stellate trichomes and trichome-like emergences in leaves. We hypothesize that these emergences could have an important role in the species’ survival due to their capacity of absorbing atmospheric moisture. Finally, the SDM supported the known habitat preferences of C. mollis and estimated a relatively wider geographic range than the currently known distribution based on herbarium records, suggesting that collecting efforts in the Amazonian region need to be increased in the future.

Morphoanatomical study, seasonal variation, and larvicidal activity of volatile oils from the leaves of Campomanesia pubescens (DC.) O. Berg (Myrtaceae)

The aim of this study was to perform from the morpho-anatomical study, physicochemical characterization, chemical composition, seasonal variability and larvicidal activity of the volatile oils of Campomanesia pubescens (DC.) O. Berg leaves. The botanical material was collected in Hidrolândia, Goiás. Morpho-anatomical characterization and phytochemical screening were performed by conventional methods. Leaf powders were submitted to hydrodistillation in the Clevenger apparatus and the identification of the chemical components of the volatile oils obtained was done by GC-MS. The larvicidal activity was carried out with third-stage larvae of the Aedes aegypti. The leaf blade, the main vein, and the young stem have a uni-stratified epidermis covered by a cuticle. The mesophyll and cortical parenchyma of the main vein and young stem have secretory cavities and idioblasts with crystals. The main rib contains a bicolateral bundle in an open arch. The young stem has a discontinuous band of sclerenchyma external to the phloem cells. Most volatile oil compounds are spathulenol, caryophyllene oxide, α-macrocarpene, and z-caryophylleneIn phytochemical analysis, tannins, digitalis, flavonoids, and total phenols were detected. The content of volatile compounds was 7.36%, that of total ash was 1.77%, and that of mucilage was 3.52 ml. The volatile oil at the concentration used was inactive against Ae aegypti larvae. The present study contributes to the taxonomic knowledge of the species and provides parameters for quality control of the plant raw material. This work represents the first description of the chemical compounds and seasonal variability of volatile oils from C. pubescens leaves collected in Goiás state.

Secretory structures of the Adesmia clade (Leguminosae): Implications for evolutionary adaptation in dry environments

The Dalbergioid Adesmia clade comprises Adesmia DC., Amicia Kunth, Nissolia Jacq., Poiretia Vent., and Zornia J.F. Gmel., all predominantly South American genera except for Zornia which has a pantropical distribution. These taxa share a shrubby or herbaceous habit with glands present on some part of the plant (e.g., stems, leaflets). However, the evolutionary relationships of the full range of secretory structures observed in previous studies are not fully understood. Thus, the goal of this study is to characterize and compare the occurrence and morphology of these glands in leaflets of species of the Adesmia clade. In addition, secretory structures were showed in a phylogenetic context in members of the Adesmia clade. The mature subterminal leaflets of 81 taxa, 79 from the Adesmia clade and two species of the Pterocarpus clade, were sampled from herbaria and living specimens. All genera of the Adesmia clade shared the presence of secretory, mucilaginous idioblasts in the epidermis of their leaflets. Genera of the clade inhabit dry environments, including open areas and highland grasslands (e.g., Savanna, Patagonian steppe, and the Andes). The presence of mucilage in the epidermis of these genera might be an adaptation to reduce water loss through transpiration, providing a hydrophilic interface between the leaflet surface and the environment, protecting plants from intensive radiation. Phenolic idioblasts were found in the mesophyll of Amicia and Zornia. Secretory cavities were observed in Amicia, Poiretia and Zornia. The occurrence of secretory cavities only in these three phylogenetically closely related genera is considered a synapomorphic character as shown by our character reconstruction analysis. The presence of secretory idioblasts is a unifying characteristic of all genera of the Adesmia clade.

Taxonomic Implications of Leaf Micromorphology Using Microscopic Analysis: A Tool for Identification and Authentication of Korean Piperales

A comparative study of the leaf micromorphology of Korean Piperales, including medicinal materials, was performed through light microscopy and scanning electron microscopy, to evaluate their taxonomic significance. Piperales possessed both amphistomatic and hypostomatic leaves. The epidermal area ranged from 38 to 5077 μm2, and the stomatal area ranged from 201 to 2129 μm2. The stomatal index on the abaxial surface was higher than that on the abaxial surface. Anomocytic stomata occurred most commonly, but actinocytic, anisocytic, tetracytic, and staurocytic stomata were also found in certain taxa. Secretory idioblasts were found on all taxa studied except Aristolochia. Three main types of trichomes were defined—(1) glandular trichome; (2) simple multicellular trichome; and (3) two-armed multicellular Y-shaped trichome. Although the quantitative data on its own had somewhat limited taxonomic value, the various qualitative characteristics (e.g., epidermal surfaces, stomata types and positions, trichome types and density, and secretory idioblast types) had great taxonomic value. These characteristics might be taxonomically relevant and useful for developing an identification key. Additionally, we evaluated and supported the previous taxonomic system of Korean Asarum, using leaf micromorphological characteristics. Finally, through the application for authentication of herbal medicine, we revealed that leaf micromorphological characteristics can be used for accurate authentication.

Anatomy and histochemistry ofManihot caerulescensPohl (Euphorbiaceae) Leaf anatomy ofManihot caerulescens

This study aimed to analyze the leaf anatomy ofManihot caerulescens, with emphasis on the ontogeny and secretion composition of the laticifers. Leaf samples were submitted the usual techniques in plant anatomy and histochemical tests to identify the main classes of secondary metabolites. The analyzes were performed using light and scanning electron microscopy. The leaves have a single layered epidermis coated by a uniform cuticle. The epidermal cells are elongated and papillose on the leaf abaxial surface of leaves. The mesophyll is isobilateral and the vascular bundle of the midrib is collateral. The laticifers are originated from ground meristem and procambium, and are of articulated anastomosing type. Besides the laticifers, two types of idioblasts were found: the secretory idioblasts, with a dense content, and the calcium oxalate druses idioblasts. Histochemical tests revealed different classes of chemicals for both secretory idioblasts and laticifers. In idioblasts, a positive reaction was detected for the general phenolic compounds, proteins, total polysaccharides and tannins. The laticifers reacted positively to total lipids and acids, essences, total polysaccharides and rubber. The individuals analyzed here are from caatinga and their leaf anatomical structure showed to be different from that described for the same species growing in the cerrado.

Microscopic diagnosis of the leaf and stem of Piper solmsianum C.DC.

Piper solmsianum C.DC., which is popularly known as pariparoba, is a shrub that measures 1-3 m in height and it inhabits areas with wet tropical soils. The objective of this study was to analyze the leaf and stem anatomy using light microscopy, scanning electron micrographs, and energy-dispersive X-ray spectroscopy in order to provide information for species identification. The anatomical profile showed the following main microscopic markers: hypostomatic leaf; hypodermis layer on both sides; pearl glands; biconvex midrib shape; five collateral vascular bundles in open arc with the central bundle larger than the others; circular stem shape; collateral vascular bundles arranged in two rings; sinuous sclerenchymatic sheath in the pith; secretory idioblasts; and starch grains in the mesophyll, in the ground parenchyma of the midrib, petiole, and in the stem; and six morphotypes of calcium oxalate crystals (styloids, cuneiform, tabular crystal rosettes, cuneiform crystal rosettes, elongated square dipyramids, as well as very elongated square dipyramids).

Protection and attraction: bracts and secretory structures in reduced inflorescences of Malpighiales

Flower protection and attraction of pollinators are mainly associated with the secretory structures. The flower-pollinator relationship corroborates these functions and is an essential link in the interpretation of different floral morphologies, such as the pseudanthia occurring in Euphorbiaceae and Peraceae, two near families in Malpighiales with several bracts and nuptial glands. Therefore, the aim of this study was to analyze the ontogeny and structure of glands and bracts present in unique, reduced inflorescences of Malpighiales, present exclusively in Euphorbiaceae and Peraceae, as well as the relationship of these structures with the floral morphology of the species. Dalechampia (Acalyphoideae), Euphorbia (Euphorbioideae), and Pera (Peraceae) pseudanthia were compared to Joannesia (Crotonoideae) flowers with regards to the strategies related to the presence of whorls and types of glands. Bracts and bracteoles have similar anatomical characteristics and compose the involucre and involucel of the pseudanthia. Some of these structures have a protection function, and others are used to attract pollinators as they are colorful and modified in glands. Colleters are found in early stages of development in Dalechampia and Euphorbia, and secretory idioblasts and laticifers occur in several stages of Pera and Joannesia, secreting exudates composed of mucilage, proteins, fatty acids and phenolic compounds, which act as protection. The resin gland of Dalechampia and nectaries of Euphorbia are derived from the involucral bracts, what is not observed in the nectaries of Joannesia. In this species, osmophores are present in the petals (first described here for the family) and act as nuptial glands. Secretory structures and different levels of bracts are related to morphological variation and the evolutionary history of the group and are important for the protection of fertile organs, pollination and species perpetuation.

Anatomy, Histochemistry, and Antifungal Activity of Anacardium humile (Anacardiaceae) Leaf.

Leaves of Anacardium humile are used in Brazilian traditional medicine for the treatment of intestinal disturbances and skin lesions. This study aimed to define leaf diagnostic structural characters, to propose a new method of phytochemical analysis of secretions, prospect flavonoids and alkaloids, and to evaluate their inhibitory activity on Candida albicans. Common anatomical, phytochemical, and microbiological methods were used. Leaves of Anacardium occidentale were used as a reference for the structural analyses. The main structural characters were closed vascular system, absence of ducts at the medulla, bilateral mesophyll, absence of bundle sheath extension, and secretory idioblasts at the xylem. The ducts present schizogenous origin, and secreting activity is restricted to the initial phases of leaf blade expansion. The proposed new phytochemical method is practical and inexpensive and has potential for wide application. The abundance of tannins and flavonoids is related to medicinal use. A single peak in high-performance liquid chromatography indicated the presence of a pure substance not previously reported. The extract had a strong inhibitory effect on C. albicans. The obtained results confirm the potential of A. humile for the prospection of new bioactive compounds.

Leaf anatomy as subsidy to the taxonomy of wild Manihot species in Quinquelobae section (Euphorbiaceae)

This work aims to characterize the anatomy of leaves of wild Manihot species (Euphorbiaceae) and identify anatomical characteristics of taxonomic importance. Samples of M. violacea var. cecropiaefolia, M. violacea var. divergens, M. violacea ssp. jacobinensis (Lencois) and M. violacea were collected in cerrado (savanna), and samples of M. violacea ssp. jacobinensis and M. violacea ssp. jacobinensis (Mucuge) were collected in campo rupestre (rocky land) areas in northeastern Brazil. The leaf anatomy of these species was analyzed using optical and scanning electron microscopy in order to obtain useful characters for the taxonomy of the genus. Information acquired confirms the records from the literature for the genus. The taxonomic characters that were considered to be the most important are as follows: number of vascular bundles and petiole outline; distribution of secretory idioblasts; and presence of papillae and midrib outline. All of these species have secretory idioblasts, crystals, laticifers and isobilateral mesophyll. Most of the species present a cylindrical petiole outline. The number of vascular bundles on the petiole varies between five and ten. The similarity analysis reinforces M. jacobinensis as a distinct species.

Light microscopy survey of extant gymnosperm root protophloem and comparison with basal angiosperms

Gymnosperm root protophloem is not well understood. There is a question as to whether root protophloem cells mature as phloem parenchyma, or as sieve elements, or if within the protophloem there is an anatomical and evolutionary gradient having characteristics of both cell types. This question is relevant to understanding anatomical and physiological mechanisms that supply nutrients to the root tip. Anatomical data from a broad range of species show that gymnosperms have one to three layers of parenchymatous protophloem cells located at the vascular cylinder periphery between the pericyle and the metaphloem. In some species, these cells are associated with secretory idioblasts. Near the root apex, protophloem cells develop a large central vacuole and, in transverse sections, their radial walls tend to be radially elongated. When mature, these cells are highly longitudinally elongated. Only these cells exhibit surging toward the root apex during chemical fixation. These data indicate that protophloem of gymnosperm roots lacks sieve elements. Because of its distinctive anatomical characteristics and the absence of sieve elements, gymnosperm root protophloem is a vegetative synapomorphy among extant species. The restriction of this tissue type to gymnosperms supports the hypothesis that it originated in a progenitor of that clade.

Estruturas secretoras da lâmina foliar de amapá amargo (Parahancornia fasciculata, Apocynaceae): histoquímica e doseamento de flavonoides

Amapá amargo (Parahancornia fasciculata (Poir.) Benoist) produz um látex, que se presume ter propriedades medicinais, pois é usado no tratamento da malária, problemas pulmonares, gastrite, e como um agente de cura. Este estudo teve como objetivo analisar estrutural e histoquimicamente os locais de produção e/ou acumúlo de compostos biologicamente ativos, bem como realizar o doseamento de flavonóides presentes no limbo do amapá amargo. Para a análise estrutural e histoquímica foram utilizados protocolos padrão em anatomia vegetal. Considerando que, para o doseamento de flavonóides utilizou-se a espectrometria de absorção na região ultravioleta-visível. O sistema secretor das folhas de amapá amargo é constituído de idioblastos secretores e laticíferos ramificados. Os testes histoquímicos revelaram diferentes tipos de substâncias químicas nos protoplastos celulares de idioblastos e laticíferos. Propriedades farmacológicas do látex de amapa amargo podem ser atribuídas à dois compostos químicos (flavonoides e alcaloides) encontrados neste estudo, ambos estão presentes em idioblastos e laticíferos.

Anatomia foliar de espécies de <I>Eugenia</I> L. (Myrtaceae) oriundas da restinga de Algodoal/Maiandeua-Pará

The increase in the number of species of Myrtaceae analyzed anatomically is needed to verify the reliability of higher taxonomic inferences. In order to contribute with structural data to Myrtaceae family and to Eugenia genus, the leaf anatomical structure of E. biflora (L.) DC., E. flavescens DC., E. patrisii Vahl. And E. tapacumensis Berg. arising from the sandy coastal Algodoal/Maiandeua-Pará was described. Some characteristics were irrespective of the four examined species: adaxial surface of epidermal cells with sinuous anticlinal walls; thick leaf cuticle; non-glandular unicellular trichomes; hypostomatic leaves; paracytic and anomocytic stomata; dorsiventral mesophyll; secretory cavities with positive oil content, principally at palisade parenchyma; secretory idioblasts with positive phenol and oil contents; bicollateral bundle on the midrib and petiole. The leaf anatomical structure of four examined species of Eugenia showed universal features to Myrtaceae.

Leaflet secretory structures of five taxa of the genus Zornia J.F. Gmel. (Leguminosae, Papilionoideae, Dalbergieae) and their systematic significance

A survey of the secretory structures of leaflets has been carried out for five taxa of the genus Zornia J.F. Gmel. to assess possible taxonomic value of the glands, taking into account that these taxa, Zornia curvata Mohlenbr., Z. gemella Willd. ex Vogel, Z. glabra Desv., Z. latifolia Sm. and Z. reticulata Sm., have overlapping diagnostic characters. The leaflet secretory structures of the five studied taxa of Zornia were mucilage epidermis, mucilage cavities, and idioblasts secreting phenolic compounds. Mucilage epidermis is found in all five aforementioned taxa. Mucilage cavities are observed on both epidermal surfaces of the leaflets in four taxa, the exception being Z. glabra, whose cavities occur only on the abaxial surface. Idioblasts secreting phenolic compounds were detected only in the mesophyll of Z. latifolia and Z. reticulata. The joint occurrence of mucilage epidermis with mucilage cavities seems to be of unifying value for the five taxa analyzed. The position of mucilage cavities and the occurrence of secretory idioblasts in the mesophyll of the leaflets are of diagnostic value, providing a key to enable identification of the taxa studied. This study reveals that the secretory structures provide important information in support of systematic studies of the Leguminosae. In relation to the five taxa of Zornia studied, current results suggest recognition of four species: Z. curvata, Z. glabra, Z. latifolia, and Z. reticulata.

Leaf and calycine colleters in Odontadenia lutea (Apocynaceae - Apocynoideae - Odontadenieae): their structure and histochemistry

The structure and histochemistry of colleters found on the vegetative and floral apices of Odontadenia lutea are described. Colleters occur on vegetative apices starting at the fourth node, with 68 to 80 colleters being found at each node. Each leaf primordium has only one colleter of axillary origin, 3-5 intra-petiolar, and 12-16 inter-petiolar (intra-stipular). There are four types of colleters: standard, bipartite standard, sessile, and bipartite sessile. Colleters on the reproductive apices alternate with the sepals and are sessile, reduced sessile, tripartite laminar sessile, or asymmetrical. All of the colleters have a central nucleus of parenchymatous cells covered by a palisade uniseriate secretory epidermis and a thin cuticle. Secretory idioblasts were observed in the parenchymatous axis. Vascularization was observed only in standard axillary and laminar colleters. Crystals were observed in the parenchyma of the axillary colleter. Histochemical tests demonstrated that there was no rupturing or distension of the cuticle during the secretion process. Mucilage was identified using the PAS reaction as well as by Mayer's reagent and Ruthenium red staining. The calycine colleters had two distinct secretory phases, the first synthesizing mucilage and the second producing phenolic compounds.

Leaf and calycine colleters in Odontadenia lutea (Apocynaceae - Apocynoideae - Odontadenieae): their structure and histochemistry

The structure and histochemistry of colleters found on the vegetative and floral apices of Odontadenia lutea are described. Colleters occur on vegetative apices starting at the fourth node, with 68 to 80 colleters being found at each node. Each leaf primordium has only one colleter of axillary origin, 3-5 intra-petiolar, and 12-16 inter-petiolar (intra-stipular). There are four types of colleters: standard, bipartite standard, sessile, and bipartite sessile. Colleters on the reproductive apices alternate with the sepals and are sessile, reduced sessile, tripartite laminar sessile, or asymmetrical. All of the colleters have a central nucleus of parenchymatous cells covered by a palisade uniseriate secretory epidermis and a thin cuticle. Secretory idioblasts were observed in the parenchymatous axis. Vascularization was observed only in standard axillary and laminar colleters. Crystals were observed in the parenchyma of the axillary colleter. Histochemical tests demonstrated that there was no rupturing or distension of the cuticle during the secretion process. Mucilage was identified using the PAS reaction as well as by Mayer's reagent and Ruthenium red staining. The calycine colleters had two distinct secretory phases, the first synthesizing mucilage and the second producing phenolic compounds.

Phenolic Compounds in Leaves of Alchornea Triplinervia: Anatomical Localization, Mutagenicity, and Antibacterial Activity

Phenolic compounds are produced by secretory idioblasts and hypodermis, and by specialized cells of the epidermis and chlorenchyma of leaves of Alchornea triplinervia. Phytochemical investigation of these leaves led to the isolation of the known substances quercetin, quercetin-7-O-beta-D-glucopyranoside, quercetin-3-O-beta-D-glucopyranoside, quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-alpha-L-arabinopyranoside, amentoflavone, brevifolin carboxylic acid, gallic acid, and methyl gallate from the methanolic extract, and stigmasterol, campesterol, sitosterol, lupeol, friedelan-3-ol, and friedelan-3-one from the chloroform extract. In studies of antibacterial activity and mutagenicity, the methanolic extract showed promising activity against Staphylococcus aureus (MIC = 62.5 microg/mL) and was slightly mutagenic in vitro and in vivo at the highest concentrations tested (1335 mg/kg b.w.).

Foliar anatomy of the species Lantana camara and L. radula (Verbenaceae)

The species Lantana camara, commonly used as ornamental, has spread worldwide becoming one of the world's most important weeds. To develop new methods of control of this plant, it is essential to distinguish it from other species of the same genus, and this is usually accomplished through taxonomic studies of fertile samples. Considering the similarity between L. camara and L. radula, and the consequent difficulty in distinguishing one from the other when only sterile samples are available, this work aimed to investigate the use of the anatomical characteristics of the leaves of both species as tools for supporting correct classification. The leaves of L. camara and L. radula were anatomically examined by light microscopy and scanning electron microscopy. The major differences were observed in the petiole, which presented secretory idioblasts in L. camara. Secretory idioblasts were observed in the leaf blades of L. camara and Crystalliferou idioblasts were found in L. radula. Glandular and nonglandular trichomes as well as the abaxial surface are different in each species. Such results can support the strategies aiming at the control of L. camara without interfering with L. radula.