Search Results (19)

Cymbidium are endangered and ornamental orchids, and the taxonomy and species identification of this genus have been debated due to some overlapping morphological features between taxa and limited data being available. The leaf morpho-anatomy of 12 Cymbidium species from China was investigated using light microscopy and paraffin sectioning. Based on a comparative analysis, some leaf morphological features that varied between species were selected and used for taxonomic differentiation as follows: (1) The shape and structure of leaves were varied and could be used for species delimitation. (2) Microscopic characteristics show that the leaves lacked trichomes and displayed polygonal to rectangular epidermal cells on both surfaces, with larger adaxial cells and more abaxial stigmata. Stomata were mostly distributed only on the abaxial side, but on both sides in Cymbidium mastersii, which exhibited a rare amphistomatic type. The stomatal complex was uniformly tetracytic in 11 species, while it was observed to be anomocytic in C. floribundum. (3) Anatomically, two distinct midrib configurations were identified, a shallow V-shape and V-shape. The mesophyll cells were homogeneous in 10 species, with the exception of a layer of parenchyma cells resembling palisade cells occurring in C. lancifolium and C. qiubeiense. The thickness of the cuticle varied between species, with the adaxial surface covered by a thicker cuticle than the abaxial surface and displaying either a smooth or corrugated surface. A fiber bundle was observed in six species, but absent in the other six. In the former group, the fiber bundle occurred adjacent to both epidermal cells in C. mastersii and C. hookerianum, while it was adjacent to the abaxial epidermis in four other species. The stegmata, with conical, spherical silica bodies, were associated with fiber bundles and mesophyll in seven species, but absent in the other five (C. kanran, C. defoliatum, C. floribundum, C. lancifolium, and C. serratum). Three kinds of crystals were identified, namely the terete bundle, the long tube bundle, and the raphide. (4) It was suggested that some of these variable features could be selected and used for the delimitation of the species and taxonomy of Cymbidium. In addition, a key to the 12 Cymbidium species based on their leaf morpho-anatomic features was proposed, which could lead to a better understanding of the taxonomy and conservation of Orchidaceae. Full article

This study reports two novel species, Gogorevia contracta sp. nov. and G. recticentralis sp. nov., which were isolated from freshwater environments in South Korea. Using an integrative taxonomic approach, we conducted morphological analyses using light microscopy and scanning electron microscopy, along with molecular phylogenetic investigations using SSU rRNA and rbcL gene sequences. Phylogenetic reconstructions highlighted the distinct characteristics of both species, confirming their classification within the genus Gogorevia and elucidating their evolutionary relationships. Morphologically, G. contracta was characterized by a bow-tie-shaped central area and circular depressions in the rapheless valve, whereas G. recticentralis exhibited a rectangular-to-wedge-shaped central area with parallel striae near the center of the raphe valve. Our findings highlighted the ecological significance of Gogorevia species and suggested their potential role as bioindicators of water quality in relatively unpolluted freshwater systems. Over the past decade, our research has focused on the taxonomic and ecological study of diatoms in the Han River system and identified 136 species, including nine newly described taxa. The findings of the present study contribute to a growing understanding of Gogorevia diversity, underscore the importance of region-specific diatom indices, and support the integration of morphological and molecular methods into diatom systematics. Full article

Developmental changes in the anatomy along with the maturation from ovaries to fruits and ovules to seeds were analyzed in two terrestrial species of the related genera Anacamptis and Serapias (Orchideae, Orchidaceae), using light and scanning electron microscopy. Our results show that the proliferation of the placentae and the differentiation of the ovules are well developed at the beginning of the anthesis. After fertilization of the ovules, a cavity of free air space is formed surrounding the embryo, contributing to the later buoyancy of seeds in both genera. At the last days of their development, the seeds showed slanting ridges in the periclinal walls of the testa cells. Raphides were observed in the valves, formed by packed needles composed of calcium oxalate, which contribute to avoiding herbivory. Lignification observed in the endocarp cells of the placenta and in the testa cells can be related to protecting the ovules and embryos. Terrestrial orchids need a faster maturation to ensure the efficacy of fertilization due to seasonal environmental changes in temperate areas, so developmental changes during the maturation of fruits and seeds take place in a shorter time than in epiphytic orchids. Full article

Numerous organisms, including animals, plants, fungi, protists, and bacteria, rely on toxins to meet their needs. Biological toxins have been classified into three groups: poisons transferred passively without a delivery mechanism; toxungens delivered to the body surface without an accompanying wound; and venoms conveyed to internal tissues via the creation of a wound. The distinctions highlight the evolutionary pathways by which toxins acquire specialized functions. Heretofore, the term venom has been largely restricted to animals. However, careful consideration reveals a surprising diversity of organisms that deploy toxic secretions via strategies remarkably analogous to those of venomous animals. Numerous plants inject toxins and pathogenic microorganisms into animals through stinging trichomes, thorns, spines, prickles, raphides, and silica needles. Some plants protect themselves via ants as venomous symbionts. Certain fungi deliver toxins via hyphae into infected hosts for nutritional and/or defensive purposes. Fungi can possess penetration structures, sometimes independent of the hyphae, that create a wound to facilitate toxin delivery. Some protists discharge harpoon-like extrusomes (toxicysts and nematocysts) that penetrate their prey and deliver toxins. Many bacteria possess secretion systems or contractile injection systems that can introduce toxins into targets via wounds. Viruses, though not “true” organisms according to many, include a group (the bacteriophages) which can inject nucleic acids and virion proteins into host cells that inflict damage rivaling that of conventional venoms. Collectively, these examples suggest that venom delivery systems—and even toxungen delivery systems, which we briefly address—are much more widespread than previously recognized. Thus, our understanding of venom as an evolutionary novelty has focused on only a small proportion of venomous organisms. With regard to this widespread form of toxin deployment, the words of the Sherman Brothers in Disney’s iconic tune, It’s a Small World, could hardly be more apt: “There’s so much that we share, that it’s time we’re aware, it’s a small world after all”. Full article

As a popular vegetable in Yunnan Province, China, taro flowers are delicious but contain substances that can cause numbing and mucous membrane damage. Prolonged high-temperature cooking is used by locals to mitigate these effects, though its mechanisms were previously unexplored. This study confirms the presence of needle-like calcium oxalate crystals in taro flowers and shows that prolonged steaming reduces their quantity, size, and sharpness, making them safer to eat. Microscopic observations revealed numerous sharp-tipped (~50 μm) calcium oxalate crystals in fresh taro flowers. After 2 h of steam heating, there were significantly fewer (~80% reduction) and smaller crystals (~70% reduction). Ion chromatography showed no significant change (p > 0.05) in calcium oxalate content (remaining ~2.5% of dry weight) after heating. Higher temperatures increase calcium oxalate solubility, causing gradual dissolution and the likely formation of small irregular structures, thus reducing the numbing effect. Prolonged cooking could be applied to other plant-based foods and medicines rich in these crystals. By analyzing statistics related to taro and taro flowers, the estimated potential economic benefits of commercializing taro flowers were USD 2.58–12.92 billion annually, potentially improving food security, creating jobs, and promoting development across regions where taro is largely cultivated in the Global South. Full article

The spotted alfalfa aphid (Therioaphis trifolii) is a kind of destructive pest of cultivated alfalfa (Medicago sativa) that results in significant financial losses for the livestock sector. To understand how T. trifolii navigates the biochemical defenses of its host, we investigated the effects of susceptible and resistant aphid strains on two alfalfa cultivars. T. trifolii was reared for over 50 generations on two cultivars—WL343, which is susceptible to T. trifolii, and Zhongmu No. 1, which is resistant—resulting in the development of a resistant aphid strain (R-aphid) and a susceptible aphid strain (S-aphid). The results showed that the survival rate of R-aphids was significantly higher than that of S-aphids (p = 0.039) on the resistant cultivar Zhongmu No. 1, while there was no significant difference in survival rates between the two aphid strains on WL343 (p = 0.139). This suggests that S- and R-aphids differ in their ability to modulate plant defense mechanisms, influencing their survival rates. The application of saliva from R-aphids reared on Zhongmu No. 1 (R-saliva) reduced the repellency and toxicity of treated plants, improving aphid survival. Furthermore, R-aphid infestation and R-saliva application activated the salicylic acid (SA) signaling pathway while suppressing the jasmonic acid (JA) pathway, enhancing the host plant’s suitability for aphid colonization. We propose that R-aphids may use their saliva to activate the SA pathway, which in turn inhibits JA synthesis, weakening the plant’s defenses. These findings provide valuable insights into how T. trifolii interacts with host plant defense systems. Full article

The increasing amount of plastic debris in water ecosystems provides a new substrate (epiplastic microhabitats) for aquatic organisms. The majority of research about epiplastic communities has focused on seawater environments, while research is still quite limited and scattered concerning freshwater systems. In this study, we analyze the first stages of colonization on different types of plastic by a periphytic algae community (its composition and dominant species complex) in freshwater bodies located in a nature reserve (within the Middle Volga Basin). A four-week-long incubation experiment on common plastic polymers (PET, LDPE, PP, and PS), both floating and dipped (~1 m), was conducted in two hydrologically connected karst water bodies in July 2023. The composition of periphytic algae was more diverse (due to the presence of planktonic, benthic, and periphytic species) than the phytoplankton composition found in the water column, being weakly similar to it (less than 30%). Significant taxonomic diversity and the dominant role of periphytic algae were noted for diatoms (up to 60% of the total composition), cyanobacteria (up to 35%), and green (including Charophyta) algae (up to 25%). The composition and structure of periphytic algae communities were distinct between habitats (biotope specificity) but not between the types of plastic, determined primarily by a local combination of factors. Statistically significant higher values of abundance and biomass were demonstrated for some species, particularly for Oedogonium on PP and Nitzschia on LDPE (p-value ≤ 0.05). As colonization progressed, the number of species, abundance, and dominance of individual taxa increased. In hydrologically connected habitats, different starts of colonization are possible, as well as different types of primary succession (initiated by potentially toxic planktonic cyanobacteria or benthic cyanobacteria and mobile raphid diatoms). Within the transparency zone, colonization was more active on the surface (for example, in relation to green algae on PP (p-value ≤ 0.05)). These results indicate a tendency for microalgae communities to colonize actively submerged plastic materials in freshwater, and they may be useful in assessing the ecological status of these aquatic ecosystems. Full article

Grapevine leaves contain abundant CaO_x crystals located either within the mesophyll in the form of raphides, or in the bundle sheaths as druses. CaO_x crystals function as internal carbon pools providing CO₂ for a baseline level of photosynthesis, named “alarm photosynthesis”, despite closed stomata; thus, preventing the photoinhibition and the oxidative risk due to carbon starvation under adverse conditions. Structural and functional leaf traits of acclimated grapevine plants (Vitis vinifera L. cv. Assyrtiko) were investigated in response to water availability, in order to evaluate the dynamic functionality of CaO_x. Leaf water potential, leaf area, leaf mass per area, stomatal properties, gas exchange parameters and performance index (PI) were decreased in leaves of vines acclimated to water deficit in comparison to the leaves of well-irrigated vines, although the chlorophyll fluorescence parameters showed that the operational efficiency of the photosystem II (PSII) photochemistry (F_v/F_m) did not change, indicating that the photosynthetic apparatus was not subjected to water stress. During the afternoon, more than half of the morning’s existing druses disappeared in the drought-acclimated leaves. Also, the raphides’ area of the drought-acclimated leaves was reduced more than that of the well-watered leaves. The substantial decomposition of druses under water deficit conditions compared to that of the raphides may have important implications for the maintenance of their different though overlapping roles. According to the results, it seems likely that, under water deficit conditions, a mechanism of “alarm photosynthesis” provides an additional tolerance trait in the leaves of Vitis vinifera cv. Assyrtiko; hence, leaf structure relates to function. Full article

The orchid genus Brachystele Schltr. (Orchidoideae, Cranichideae, Spiranthinae) comprises 20 species distributed from Mexico to Argentina, with 10 species found in Brazil. Anatomical studies of Orchidoideae Lindl. have been scarce, and the anatomy and histochemistry of Brachystele are still largely unknown. In this study, we conducted a characterization of the vegetative organs of B. guayanensis (Lindl.) Schltr. using standard anatomical and histochemical microtechniques. In this study, we provide the first information about the anatomy and histochemistry of Brachystele. The studied species was observed to display anatomical characters commonly found in the vegetative organs of representatives of the Cranichideae tribe (e.g., uniseriate epidermis; homogeneous mesophyll with 6–11 layers; rhizomes with rings of fibers; vascular bundles in the form of “^” or “v”; fleshy roots with uniseriate velamen, simple trichomes, and spiranthosomes). Others can be interpreted as adaptive strategies conditioned by the environment and their terrestrial life form (e.g., cuticle thickness; amphistomatic leaves; roots with reduced velamen compared to the cortex (18–20 layers); and raphides). In this study, cataphylls, and the presence of spiranthosomes in leaves, including stomatal guard cells, as well as alkaloids in these structures, are anatomically described for the first time in Orchidaceae. The presence of hyphae and pelotons in the stem of B. guayanensis is described for the first time in Cranichideae. Histochemical tests confirmed the presence of lignin, proteins, and alkaloids, the lipidic nature of the cuticle, starch grains stored in spiranthosomes, and the composition of the raphides. Alkaloids were observed in abundance, particularly in the roots, suggesting a potential role in defense against pathogens and herbivores, as well as potential medicinal activities, as seen in phylogenetically related groups to Brachystele. Full article

Calcium oxalate phytoliths are one of the most prominent types of Ca speciation in the plant kingdom, and they store extensive amounts of carbon in crystalline form. Ca phytoliths were investigated in the root, trunk, and bark of Vitis vinifera Chasselas from a vineyard in Alsace, France. A multi-analytical approach was used, which included SEM coupled with EDX spectroscopy, XRD, XRF, TGA, and ¹³C-NMR spectroscopy. These techniques revealed that phytoliths are composed of crystalline calcium oxalate monohydrate (whewellite). The whewellite crystals exhibited mostly equant or short-prismatic habits in all of the three studied grapevine parts, but bipyramidal crystals also occurred. Raphide crystals were only observed in the root, where they were abundant. Instead of using wet chemical procedures to extract the mineral components from the organic parts of the biomass, a thermal treatment via calcination was chosen. The suitable temperature of calcination was determined through TGA experiments. The calcination of the biomass samples at 250 °C enhanced the amounts of Ca phytoliths in the residual chars. The thermal treatment, however, affected the appearance of the Ca oxalate crystals by producing surfaces that displayed macroporosity and by creating fractures. For calcination at both 300 °C and 350 °C, Ca oxalate lost a molecule of carbon monoxide to form Ca carbonate, and the modifications of the original crystal surfaces were more pronounced than those observed after thermal treatment at 250 °C. Full article

Cyphostemma hypoleucum (Harv.) Desc. ex Wild & R.B. Drumm is a perennial climber, indigenous to Southern Africa, and belongs to the Vitaceae. Although there have been many studies of Vitaceae micromorphology, only a few taxa have been described in detail. This study aimed to characterize the micro-morphology of the leaf indumentum and determining its possible functions. Stereo microscope, scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to produce images. Micrographs of stereomicroscopy and SEM showed the presence of non-glandular trichomes. In addition, pearl glands were observed on the abaxial surface using a stereo microscope and SEM. These were characterized by a short stalk and a spherical- shaped head. The density of trichomes decreased on both surfaces of leaves as the leaf expanded. Idioblasts that contained raphide crystals were also detected in tissues. The results obtained from various microscopy techniques confirmed that non-glandular trichomes serve as the main external appendages of the leaves. Additionally, their functions may include serving as a mechanical barrier against environmental factors such as low humidity, intense light, elevated temperatures, as well as herbivory and insect oviposition. Our results may also be added to the existing body of knowledge with regard to microscopic research and taxonomic applications. Full article

This study investigated the anatomical and non-anatomical characteristics of six wood species, Acacia mangium, Acacia hybrid, Dillenia pentagyna, Anacardium occidentale, Hevea brasiliensis, and Melaleuca cajuputi, from a plantation in Vietnam. The anatomical characteristics and non-anatomical characteristics were observed following the International Association of Wood Anatomists (IAWA) list. All species showed diffuse porosity and non-septate fibers. Exclusively solitary vessels were only observed in M. cajuputi. Vestured pits were observed in A. mangium, A. hybrid, and M. cajuputi, and tyloses were found in A. occidentale and H. brasiliensis. We observed vasicentric axial parenchyma in A. mangium, A. hybrid, A. occidentale, and H. brasiliensis, whereas diffuse axial parenchyma was observed in D. pentagyna and M. cajuputi. Further, prismatic crystals in the axial parenchyma cells existed in A. mangium, A. hybrid, and H. brasiliensis, and raphides in ray cells were observed in D. pentagyna. Silica bodies in ray cells were found in A. occidentale and M. cajuputi. H. brasiliensis exhibited the greatest vessel diameter and ray height, with D. pentagyna exhibiting the greatest fiber length and wall thickness. All the species showed considerable differences in heartwood fluorescence, water and ethanol extract colors, and froth test reactions. Full article

Root tubers of Asphodelus bento-rainhae subsp. bento-rainhae (AbR), an endemic species with relevant interest due to conservation concerns, and Asphodelus macrocarpus subsp. macrocarpus (AmR) have been traditionally used for culinary and medicinal purposes, mainly associated with skin infection and inflammation. The present study aims to establish the quality control criteria for the proper characterization of dried root tubers of both species as herbal substances, together with their preclinical safety assessments. Botanical identification using macroscopic and microscopic techniques and phytochemical evaluation/quantification of the main classes of marker secondary metabolites, including phenolic compounds (flavonoid, anthraquinone, condensed and hydrolysable tannin) and terpenoids were performed. Additionally, in vitro genotoxicity/mutagenicity was evaluated by Ames test. Evident morphological differences in the development of tubercles (3.5 × 1 cm in AbR and 8.7 × 1.4 cm in AmR) and microscopicly in the arrangements and characteristics of the vascular cylinder (metaxylem and protoxylems) were found. Anatomical similarities such as multiple-layered epidermis (velamen) and the cortex area with thin-walled idioblasts (134 ± 2.9 µm and 150 ± 27.6 µm) containing raphide crystals (37.2 ± 14.2 µm and 87.7 ± 15.3 µm) were observed between AbR and AmR, respectively. Terpenoids (173.88 ± 29.82 and 180.55 ± 10.57 mg OAE/g dried weight) and condensed tannins (128.64 ± 14.05 and 108.35 ± 20.37 mg CAE/g dried weight) were found to be the main class of marker secondary metabolites of AbR and AmR extracts, respectively. No genotoxicity (up to 5 mg/plate, without metabolic activation) was detected in these medicinal plants’ tested extracts. The obtained results will contribute to the knowledge of the value of the Portuguese flora and their future commercial cultivation utilization as raw materials for industrial and pharmaceutical use. Full article

Calla lily (Zantedeschia albomaculata (Hook.) Baill.) is an herbaceous or semi-evergreen perennial grown from rhizomes. It is commonly named “Spotted Arum”. Ribosomal RNAs (rRNAs) are found in all known organisms and are known for being functionally equivalent in all of them. A completely new in vitro culture protocol was applied to Z. albomaculata with two hormones, 6-Benzylaminopurine (BAP) and kinetin, to obtain full growth and multiplication. Due to their highly conserved sequences, the analysis of small-subunit rRNAs (16S–18S rRNAs) can provide precise statistical evaluation of a wide variety of phylogenetic connections. As a result, the plant’s 18S rRNA gene allowed for identification and partial sequencing. Also, the traditional floral method and the novel application technique for identification were applied to Z. albomaculata. In this paper we systemically describe the structural strategies of the plant’s adaptation to the surroundings at the morphological, physiological, and anatomical scale. Most the essential oils and fatty acids found in Z. albomaculata are omega fatty acids, octadecenoic acid, linoleic acid, and palmitic acid. All these fatty acids have industrial, medicinal, and pharmaceutical applications. The significant findings are the spadix sheathing leaves, and the precipitation of raphides calcium oxalate. The mitotic index showing the division activity was recorded, and it was 17.4%. The antimicrobial activity of Z. albomaculata ethanol extract was performed via the well diffusion method. This extract has shown high activity against Escherichia coli and Pseudomonas aeruginosa, compared to its lower activity against Bacillus cereus. By defining these characteristics and in vitro culture conditions, we will be able to acclimatize the plant in greenhouses, and then transfer it to the open field. The findings of this work identified the general characteristics of Zantedeschia albomaculata as an ornamental and medicinal plant in order to acclimatize this plant for cultivation in the Mediterranean climate. Full article

Many orchid species have evolved complex floral signals to ensure pollination efficiency. Here, the authors combined analyses of anatomical flower structure with analyses of the volatile composition and flower-visiting insects’ behaviour, as well as characterised features that can attract pollinators of the inconspicuous orchid Malaxis monophyllos. During field observations, the authors found that only small Diptera (e.g., mosquitos, drosophilids, fungus gnats) visit and are interested in the flowers of M. monophyllos, which was reflected in the characterised flower features that combine well with the pollination system, which engages dipterans. Analyses of the M. monophyllos floral scent revealed substantial concentrations of aliphatic compounds, e.g., 1-octen-3-ol and 1-octanol, which condition the mushroom-like scent and a substantial fraction of alkanes, some of which have been previously described as sex mimicry and aggregation pheromones in orchids’ deceptive systems. The labellum anatomical structure exhibits a highly diverse cell cuticle surface and pronounced metabolic and secretory activity of the epidermal and subepidermal cells from all parts of the labellum. Moreover, our study provides evidence for the subsequent decoys of M. monophyllos flowers, including visual signals, such as raphides located on the labellum margin and the rewarding ones connected with lipid secretion limited to the area behind the column. Taking an integrative approach to studying M. monophyllos pollination biology, the authors provide new insight into its previously vague pollination strategies and provide evidence for complex floral signal operation in luring potential pollinators. The synergistic effect of M. monophyllos flowers’ volatile and visual signals, together with additional rewarding for nectar/fungus/microbe-feeding pollinators, requires further detailed investigation that will be invaluable in explaining the evolution of Diptera-specific pollination systems in orchids. Full article