Morphology and Anatomy of Leaf, Stem and Petiole of Luvunga crassifolia Tanaka (Rutaceae)

Luvunga crassifolia is an underutilized plant in the Citrus family. Other than brief morphological descriptions, there are no published reports on other identification features of this plant. Thus, the current study was aimed to investigate macroscopic and microscopic diagnostic features of L. crassifolia leaves, stems, and petioles. Macroscopic characterization, optimization of histological procedure, and histochemical analyses of differential stains were carried out on the leaves, stems, and petioles of L. crassifolia. The histological method was optimized by modifying the following parameters: number of fixation days, dehydration duration with degraded series of ethanol or butanol, clearing duration, and infiltration duration. After infiltration, embedding and sectioning of the tissues were performed. Histochemical analyses were carried out using differential stains to identify the cellular components in leaf, stem and, petiole tissue sections. This study showed that L. crassifolia leaves are amphistomatic. Pellucid dots were observed on both adaxial and abaxial leaf surfaces. Secretory cavities, xylem, phloem, and pericyclic fibers were found in the cross-sections of leaf, stem, and petiole. Calcium oxalates were present in the leaf and stem sections, while trichomes were detected in stem and petiole sections. The information obtained from this study will be helpful for the identification and future taxonomic-related studies of this plant species.

Callus of Curculigo latifolia Dryand. ex W.T. Aiton: initiation, regeneration, secretory structure and histochemistry

In Indonesia, Curculigo latifolia, popularly known as lemba, is used as traditional medicine for antihypertension, antidiabetic, and as a food and drink additive. Despite the high benefits, this plant is difficult to propagate due to its low seed viability. Tissue culture offers an alternative for plant propagation, thus providing a continuous source of bioactive substances. The study aimed to establish efficient methods of explant sterilisation, callus induction and its regeneration from leaf tissues for plant multiplication. The study also investigated histochemically secondary metabolites produced by the callus. Our results showed that sterilising agents in the lowest concentrations and the shortest duration was the most suitable for getting aseptic cultures. BAP (3 mg L−1) and IBA (5 mg L−1) were the highest callus initiation, shoots, and roots regeneration. The histological sections of fresh callus showed secretory structure in the form of secretory cavities surrounded by a layer of epithelial cells and idioblasts around the secretory cavities. The histochemical tests identified phenolic compounds and essential oils in organogenic callus. Idioblasts were detected containing essential oils too. The results will contribute to C. latifolia propagation and the development of callus as a producing source of secondary metabolites.

Struktur Sel Sekresi Daun Jeruk Kalamansi (Citrus microcarpa Bunge.) di Pulau Ambon

Perbedaan lokasi tumbuh dapat mengakibatkan perbedaan penampilan fenotipik tanaman yang dapat diamati secara morfologi dan anatomi seperti struktur anatomi sel sekretori. Tujuan penelitian ini adalah untuk mengetahui struktur sel sekretori daun jeruk kalamansi di pulau Ambon. Metode jelajah dilakukan pada 13 lokasi di Pulau Ambon untuk koleksi sampel, dan pada setiap lokasi diambil 3 tanaman sebagai 3 ulangan. Tiap tanaman diambil 5 daun pada setiap sisi pohon tanaman jeruk kalamansi dengan ukuran panjang 5-7 cm dan warna hijau tua. Pembuatan preparat mengikuti metode free hand section. Pengamatan menggunakan kamera Optilab pada mikroskop Olympus dengan perbesaran 400x. Pengukuran diameter sel menggunakan fitur measure pada software Image Ruster. Data kualitatif berupa struktur sel sekresi daun jeruk Kalamansi ditampilkan dalam bentuk gambar dan dideskripsikan sesuai hasil yang terlihat, sedangkan data hasil pengukuran diameter sel sekresi adalah rerata 3 ulangan dan ditampilkan sebagai mean ± standar deviasi (SD). Hasil penelitian menunjukkan adanya sel sekretori yang berjumlah satu sel. Struktur sel sekretori terdiri dari sel epitel, sel selubung, dan rongga sekretori. Bentuk sel sekresi ada yang bulat dan lonjong. Diameter rongga sekretori berkisar antara 106,08-167,60 µm. Berdasarkan hasil penelitian, maka dapat disimpulkan bahwa sel sekresi pada daun jeruk kalamansi pada lokasi-lokasi berbeda di Pulau Ambon bervariasi baik bentuk maupun ukurannya. Differences in habitat can induce differences in the phenotypic appearance of plants that can be observed morphologically and anatomically such as the anatomical structure of secretory cells. The purpose of this study was to determine the structure of the secretory cells in the leaves of Calamansy citrus in Ambon island. Tracking method was done for sample collections, and at each location 3 plants were taken as replicates. Each plant was taken 5 leaves with a length of 5-7 cm and dark green color. Prior to be observed, the fresh sample was done with free-hand section method. Microscopy observations were done by a light microscope at 400x magnification. Measurement of cell diameter was done by the measure feature in Image Ruster software. Qualitative data such as secretory cell structures of Calamansy citrus leaves were shown in form of images and described according to the results, while the data of the measurement of secretory cell diameters is the average of 3 replications and was shown as mean ± standard deviation (SD). The results showed the presence of secretory cells which amounted to one cell. The secretory cell structure is composed of epithelial cells, sheath cells, and secretory cavities. Cell shapes vary, including round and oval. The diameter of the secretory cell cavity ranges from 106.08-167.60 µm.

Anatomical study of the leaves and evaluation of the chemical composition of the volatile oils from Psidium guineense Swartz leaves and fruits

Psidium guineense Swartz is a bush used in urinary tract diseases, diarrhea, and dysentery. The present study aims to perform the anatomical study of the leaves and evaluation of the chemical composition of the volatile oils from Psidium guineense Swartz leaves and fruits. The botanical material was collected in Hidrolândia, Goiás. Anatomical characterization and phytochemical screening of the leaves were performed by conventional methods. Leaf and fruit (green fruits, immature fruits, and ripe fruits) 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 leaf blade is hypoestomatic with paracytic and anisocytic stomata. Secretory cavities are observed in the central vein, mesophyll, petiole, and young stem. The powder moisture content was 7.4%. The total ash content of the leaf powder was 6.3% and the acid-insoluble ash content was 0.8%. The presence of tannins, flavonoids, and saponins in the leaves were identified. Leaves volatile oil’s majority compounds were 2Z,6E-farnesol (23.1-25.4%), α-copaene (17.7-20.3%), muurola-4,10(1.4) dien-1-β-ol (5.8-6.7%), epi-α-cadinol (5.5- 6.3%), and δ-Cadinene (5.0- 5.9%). Fruits volatile oil’s majority compounds were 2Z,6E-farnesol (31.9-41.4%), α-copaene (13.3-26.6%), δ-cadinene (5.4-9.8%), γ-himachalene (3.8-6.1%), and cubenol (2.6-6.1%). This is the first report on anatomical study of the leaves, and chemical composition of volatile oils from leaves and fruits of P. guineense collected in Hidrolândia, Goiás.

Ontogenesis, histochemistry, and seasonal and luminous environmental characterization of secretory cavities in leaves of Myrcia splendens (Myrtaceae)

Secretory cavities produce compounds that protect plants from herbivory and pathogenic microorganisms. These cavities have been reported in many genera. However, there are few studies on secretory cavity ontogeny in the genus Myrcia (Myrtaceae) as well as the effects of luminosity and seasonality on such secretory cavities. Therefore, the objective of this study was to provide new information regarding the ontogenesis, structure, histochemistry, and effects of seasonality in Myrcia splendens (Sw.) DC. We collected and analyzed leaves from 10 specimens of M. splendens exposed to sun and shade during both the wet and dry seasons. The samples were subjected to standard anatomical techniques for light microscopy. Myrcia splendens has schizo-lysigenous ontogenesis with exudates composed of lipids, essential oils, oil-resins, and alkaloids. The largest secretory cavities were found in leaves exposed to sunlight during the dry season. The presence of lipophilic compounds may be an important strategy for protecting the plant from herbivores. The seasonal variations observed in the leaf’s secretory cavities demonstrate the anatomical plasticity of such species to the availability of light and water. As the total area of the leaf cavities in M. splendens reflects the seasonal variation, this should be taken into account when aiming to grow crops for producing essential oils or for alkaloid extractions.

A correlation analysis of Light Microscopy and X-ray MicroCT imaging methods applied to archaeological plant remains’ morphological attributes visualization

In this work, several attributes of the internal morphology of drupaceous fruits found in the archaeological site Monte Castelo (Rondonia, Brazil) are analyzed by means of two different imaging methods. The aim is to explore similarities and differences in the visualization and analytical properties of the images obtained via High Resolution Light Microscopy and X-ray micro-computed tomography (X-ray MicroCT) methods. Both provide data about the three-layered pericarp (exo-, meso- and endocarp) of the studied exemplars, defined by cell differentiation, vascularisation, cellular contents, presence of sclerenchyma cells and secretory cavities. However, it is possible to identify a series of differences between the information that can be obtained through each of the methods. These variations are related to the definition of contours and fine details of some characteristics, their spatial distribution, size attributes, optical properties and material preservation. The results obtained from both imaging methods are complementary, contributing to a more exhaustive morphological study of the plant remains. X-ray MicroCT in phase-contrast mode represents a suitable non-destructive analytic technique when sample preservation is required.

Phylogenetic implications of the anatomical study of the Amburaneae clade (Fabaceae: Faboideae)

Phylogenetic analyses of early-diverging Faboideae have indicated that genera previously positioned in distinct tribes are instead closely related, e.g. in the Amburaneae clade, and the relatively recent rearrangements of many genera into clades has hampered the identification of morphological synapomorphies for previously unrecognized clades. Our aims are to evaluate anatomical vegetative characters of leaflets attached to reproductive features in the Amburaneae clade, to identify new synapomorphies for the clade and subclades, to identify characters supporting intergeneric relationships and diagnostic characters for the genus and species and to provide information about the morphology and histochemistry of secretory structures. The study was based on the anatomy of the leaflet of 19 species of the Amburaneae clade. Papillae cells, the presence of vascular system units and hypodermis are shared features of Amburaneae. Anatomical characters of the leaflet can be diagnostic at the generic and specific levels in Amburaneae. Secretory structures found in the clade are secretory cavities, secretory channels, idioblasts, mucilaginous epidermal cells and glandular trichomes. The broader concept of Amburaneae is reinforced here by morphological and molecular data, with the identification of new synapomorphies. Our dataset supports the intergeneric relationships resolved by molecular data.

Anopheles Salivary Gland Architecture Shapes Plasmodium Sporozoite Availability for Transmission

ABSTRACT Plasmodium sporozoites (SPZs) must traverse the mosquito salivary glands (SGs) to reach a new vertebrate host and continue the malaria disease cycle. Although SGs can harbor thousands of sporozoites, only 10 to 100 are deposited into a host during probing. To determine how the SGs might function as a bottleneck in SPZ transmission, we have characterized Anopheles stephensi SGs infected with the rodent malaria parasite Plasmodium berghei using immunofluorescence confocal microscopy. Our analyses corroborate findings from previous electron microscopy studies and provide new insights into the invasion process. We identified sites of SPZ accumulation within SGs across a range of infection intensities. Although SPZs were most often seen in the distal lateral SG lobes, they were also observed in the medial and proximal lateral lobes. Most parasites were associated with either the basement membrane or secretory cavities. SPZs accumulated at physical barriers, including fused salivary ducts and extensions of the chitinous salivary duct wall into the distal lumen. SPZs were observed only rarely within salivary ducts. SPZs appeared to contact each other in many different quantities, not just in the previously described large bundles. Within parasite bundles, all of the SPZs were oriented in the same direction. We found that moderate levels of infection did not necessarily correlate with major SG disruptions or abundant SG cell death. Altogether, our findings suggest that SG architecture largely acts as a barrier to SPZ transmission. IMPORTANCE Malaria continues to have a devastating impact on human health. With growing resistance to insecticides and antimalarial drugs, as well as climate change predictions indicating expansion of vector territories, the impact of malaria is likely to increase. Additional insights regarding pathogen migration through vector mosquitoes are needed to develop novel methods to prevent transmission to new hosts. Pathogens, including the microbes that cause malaria, must invade the salivary glands (SGs) for transmission. Since SG traversal is required for parasite transmission, SGs are ideal targets for transmission-blocking strategies. The work presented here highlights the role that mosquito SG architecture plays in limiting parasite traversal, revealing how the SG transmission bottleneck is imposed. Further, our data provide unprecedented detail about SG-sporozoite interactions and gland-to-gland variation not provided in previous studies.

Diversity of leaf secretory structures in five Neotropical genera of Primulaceae: ecological aspects and evolutionary significance

Many species of Primulaceae have chemical or medicinal importance, directly related to the presence of an important set of secretory structures distributed throughout the entire plant. Such structures are not only relevant in a pharmaceutical context, but also for taxonomic, systematic, and evolutionary studies within the family. Despite this, studies of the secretory structures in Primulaceae are still scarce. In this context, we aimed to identify and classify the diversity of secretory structures on the leaves of five Neotropical Primulaceae genera belonging to the Myrsinoideae and Theophrastoideae subfamilies, using light, confocal, and epifluorescence microscopy analysis. The species we studied had a diversity of secretory structures: mucilaginous and phenolic-content idioblasts, glandular trichomes, hydathodes, and secretory cavities/ducts. The development of secretory cavities and trichomes is asynchronous and begins before tissue and leaf maturation. Secretory cavities derive from a ground meristem cell and follow a schizogenous mode of development. The chemical nature of the secretion is diverse and varies according to the type of secretory structure and among species. Here, we hypothesize that both peltate glandular trichomes and secretory cavities may be considered a synapomorphy for Primulaceae. Moreover, we suggest that environmental factors have shaped the diversification of function of the secretory structures found in Primulaceae.

Ecological anatomy of Eugenia luschnathiana (O.Berg) Klotzsch ex B.D.Jacks. (Myrtaceae) leaves in the Restinga region, state of Ceara

Eugenia luschnathiana (O.Berg) Klotzsch ex B.D.Jacks. (Myrtaceae) species, commonly known as pitomba-da-baía, occurs in Restinga region in the state of Ceara and has medicinal potential. The present study aimed to characterize the anatomy of E. luschnathiana leaves in the rainy and dry seasons, as well as in the sun and shade in the Restinga region of Ceara, aiming to generate useful information to understand the adaptive value of morphoanatomic responses to the natural conditions of occurrence of the species. Collections were performed at the State Botanical Park of Ceara, and leaves were completely expanded and fixed in FAA70, being replaced by 70% ethanol after 24 h. Samples were submitted to standard plant anatomy methodologies in order to qualitatively and quantitatively analyze the leaf blade and petiole structures. As a result, there were differences among sun and shade leaves, rain and dry. In relation to luminosity, most determinations were higher in sun leaves: trichome density and frequency; trichome scar frequency; stomatal frequency, stomatal index, length, width and area of stomata; thickness of leaf blade, mesophyll, cuticle, epidermis, palisade and spongy parenchyma; length and width of the central vein, area of the central vein vascular bundle, number of secretory cavities in the central vein; length and width of the petiole, area of the petiole vascular bundle; amount and area of secretory cavities in the petiole. In shade leaves, only the number of druses in the central vein and petiole were larger. Regarding seasonality, all determinations were higher in the rainy season, except for the length and width of the central vein; number of druses in the central vein and petiole; length of the petiole, area of the vascular bundle and secretory cavities of the petiole. Therefore, it could be concluded that E. luschnathiana has great acclimative capacity to conditions of intense luminosity and periods of water deficit.