Search Results (28)

Bayberry (Morella rubra Lour.; syn. Myrica rubra (Lour.) Siebold & Zucc.) leaves are rich in bioactive compounds but remain underutilized. This study investigated the optimal harvest stage and processing methods to develop high-quality functional powder. We first compared three growth stages: red buds (RB), new leaves (NL), and old leaves (OL). RB exhibited the highest antioxidant capacity and unique volatile profile; however, NL was selected for processing optimization due to the balance between quality and biomass availability. Subsequently, NL was subjected to freeze-drying (FD), mechanical drying (MD), steaming followed by MD (S-MD), and shade drying (SD). Results showed that FD preserved the vibrant green color, glandular trichome structure, ascorbic acid, and fresh volatiles (monoterpenes). Conversely, thermal drying (MD and S-MD) disrupted cellular barriers, which facilitated the extraction of minerals and robust polyphenols like myricitrin, yielding the highest extraction of flavonoids and corresponding antioxidant activity, measured by hydrophilic oxygen radical absorbance capacity (H-ORAC), in hot water extracts than FD. SD significantly degraded quality due to prolonged enzymatic oxidation. While FD is ideal for preserving aesthetics and heat-sensitive nutrients, low-cost MD and S-MD are recommended for producing antioxidant-rich powders for functional food applications where extraction efficiency is prioritized. Full article

Nepenthes L. species (tropical pitcher plants) are a classic example of carnivorous plants. The Nepenthes traps are highly specialized pitchers with a zoned structure. On the outer surface of the pitcher, there are nectaries and various types of trichomes, including glandular trichomes. The main aim of our study was to examine these glandular trichome structures and check the distribution of the homogalacturonans (HGs) and hemicelluloses in the cell wall of trichome cells. The structure of Nepenthes bicalcarata Hook. f. and Nepenthes albomarginata T.Lobb ex Lindl. trichomes was analyzed using light and electron microscopy. The antibodies were used against the wall components [anti-pectic homogalacturonans (HGs): JIM5 (low methylesterified HGs), LM19 (low methylesterified HGs), CCRC-M38 (a fully de-esterified HGs), JIM7 (highly esterified HGs), LM20 (esterified HGs), LM5 (galactan) and anti-hemicelluloses: LM25 (xyloglucan), LM15 (galactoxyloglucan), CCRC-M138 (xylan), and LM10 antibody (xylan)]. The localization of the examined compounds was determined using immunohistochemistry techniques. The presence of endodermal and transfer cells supports the idea that peltate trichomes actively transport solutes. Also, the presence of pectic homogalacturonans and hydrophilic hemicelluloses indicates that water or aqueous solutions are transported through the trichomes’ cell walls. Our study supports the idea that these trichomes may act as hydathodes or hydropotes. Full article

The parameters and plant habitat characteristics of glandular trichomes could allow for faster and cheaper identification and selection of more essential oil-rich wild aromatic plants for further cultivation. This study aimed to establish relationships between the parameters of peltate glandular trichomes and essential oil content in commercially potential Thymus pulegioides in relation to plant sex, chemotype, and habitat characteristics. In total, 124 T. pulegioides plants belonging to different chemotypes and sexes and collected from 23 natural habitats were analysed. Essential oils were extracted by hydrodistillation, and a light microscope was used to investigate parameters of peltate glandular trichomes in upper and lower leaf epidermises. For investigation of the dynamics of the parameters of peltate glandular trichomes, T. pulegioides were growing in open ground under the same environmental conditions. Results demonstrated that the essential oil percentage in phenolic chemotype plants was higher than in plants of a non-phenolic chemotype. Females and hermaphrodites did not significantly differ according to essential oil percentage. Cover abundance of T. pulegioides negatively affects the density and diameter of peltate glandular trichomes and the essential oil percentage in T. pulegioides. The parameters of peltate trichomes in the upper leaf epidermis could be anatomical markers, helping to select T. pulegioides with higher essential oil contents from natural habitats as promising candidates as new crops. Full article

Organic agriculture has few tools against pests and diseases and is constantly looking for effective and sustainable products such as geomaterials, i.e., zeolite. This study evaluates the physiological and morphological responses of olive plants (Olea europaea) to foliar applications of different geo-materials, specifically kaolin, natural zeolite, and ammonium-enriched zeolite. The research examines leaf anatomical modifications, including internal tissue structures, trichome and stomatal density, chlorophyll content, and gas exchange parameters, alongside the impact on fruit development and extra virgin olive oil (EVOO) quality. Results indicate that kaolin application negatively influenced transpiration and stomatal conductance, an effect corroborated by increased xylem vessel wall thickness. However, the reduction in stomatal conductance was attributed to a functional rather than morphological adaptation, as no significant changes in stomatal density or size were observed. Both geo-material treatments altered leaf surface properties, particularly peltate trichome characteristics. Notably, ammonium-enriched zeolite application enhanced photosynthetic rate during early olive development, likely due to its nutritional role, and contributed to increased fruit size and oil yield. These findings highlight the potential of geo-material-based foliar treatments as an effective strategy to optimize plant physiological performance and improve olive oil production in sustainable agricultural systems. Full article

Saline environments shape plant metabolism, driving ecological and biochemical adaptations. This study investigated the impact of salinity on Adenosma indiana (Indian scent-wort), a medicinal herb known for its volatile organic compounds (VOCs) and anti-inflammatory and antimicrobial properties, to elucidate its adaptive strategies. During the flowering stage, samples were collected from four saline microhabitats in Kalasin Province, Thailand. We analyzed soil properties, plant growth, photosynthetic pigments, compatible solutes (anthocyanins, proline, total sugars), and elemental concentrations (K, Na, Ca, Mg) across different tissues. Results showed that A. indiana maintained stable growth while enhancing chlorophyll and β-carotene levels under increasing salinity. GC-MS identified 47 VOCs, including 3-cyclopenten-1-one (first reported in this species) and β-bisabolene, both strongly linked to soil salinity. In low-salinity soils, leaves accumulated high sodium, inducing osmoprotectants (proline, total sugars) and VOCs (D-limonene, α-pinene, terpinolene, 1-octen-3-ol) in peltate glandular trichomes. Conversely, in high-salinity soils, lower leaf sodium levels were associated with increased β-bisabolene and β-caryophyllene production, suggesting distinct biochemical pathways. These findings reveal salinity-driven VOC modulation in A. indiana, highlighting its adaptive potential for medicinal applications in saline environments and its role as a source of salt-tolerant bioactive compounds. Full article

Since the 19th century, the cultivation of Ocimum basilicum L. has increasingly been established in Liguria, with the in situ reproduction of seeds. Over the years, Ligurian basil accessions were crossed with allochthonous genomes to obtain disease-resistant plants. To preserve the original genetic resource, nine old Ligurian accessions (CV1–9) were recovered. As part of the PSR 2014–2022 Mis. 10.2 of Liguria Region, this work aimed to characterize these CVs by morphological and phytochemical analyses to safeguard their biodiversity. Commercial O. basilicum Genovese Superbo grown in Liguria (SL) was added for comparison. The micro-morphological investigation showed significantly different trichome densities among the samples. CV4 showed the highest densities of both peltate and capitate trichomes, while CV9 and CV1 had the lowest peltate and capitate densities, respectively. In addition, to perform the germplasm characterization, seed morphometric data and germinability were evaluated. Volatile Organic Compounds (VOCs) analysis was carried out on CV1–9, SL, and Superbo plants grown in Piedmont (SP), to test the influence of territory on basil aromatic profiles. The results showed that the old accessions and SL were rich in linalool, eugenol, and bergamotene. Only CV1 slightly differed, with higher levels of methyl eugenol, eucalyptol, and camphor. On the contrary, SP had very high levels of methyl eugenol and camphor. These data represent valuable insights for preserving Ligurian old basil accessions and maintaining the production of Genovese Basil PDO (Protected Designation of Origin) in the future. Full article

Lamiaceae is a botanical family rich in aromatic species that are in high demand such as basil, lavender, mint, oregano, sage, and thyme. It has great economical, ecological, ethnobotanical, and floristic importance. The aim of this work is to provide an updated view on the aerobiology of species from the family Lamiaceae, with an emphasis on novelties and emerging applications. From the aerobiology point of view, the greatest interest in this botanical family is related to the volatile organic compounds emitted by the plants and, to a much lesser extent, their pollen. Research has shown that the major volatile organic compounds emitted by the plants from this botanical family are monoterpenes and sesquiterpenes. The most important monoterpenes reported across studies include α-pinene, β-pinene, 1,8-cineole, menthol, limonene, and γ-terpinene. Most reports tend to cover species from the subfamily Nepetoideae. Volatile oils are produced by glandular trichomes found on aerial organs. Based on general morphology, two main types are found in the family Lamiaceae, namely peltate and capitate trichomes. As a result of pollinator-mediated transfer of pollen, Lamiaceae species present a reduced number of stamens and quantity of pollen. This might explain the low probability of pollen presence in the air from these species. A preliminary synopsis of the experimental evidence presented in this work suggests that the interplay of the organic particles and molecules released by these plants and their environment could be leveraged for beneficial outcomes in agriculture and landscaping. Emerging reports propose their use for intercropping to ensure the success of fructification, increased yield of entomophilous crops, as well as in sensory gardens due to the therapeutic effect of volatiles. Full article

The genus Phlomis is one of the largest genera in the Lamiaceae family and includes species used since ancient times in traditional medicine, as flavoring for food and as fragrance in cosmetics. The secretory structures (represented by glandular trichomes) as well as the essential oils produced by them constitute the subject of this review. While representatives of this genus are not typically regarded as large producers of essential oils compared to other species of the Lamiaceae family, the components identified in their essential oils and their biological properties necessitate more investigation of this genus. A comprehensive analysis of the specialized literature was conducted for each of the 93 currently accepted species to identify all the results obtained by researchers regarding the secretory structures and essential oils of this genus up to the present time. Glandular trichomes, still insufficiently studied, present morphological peculiarities that differentiate this genus within the family: they are of two categories: capitate (with a wide distribution in this genus) and dendroid. The peltate trichomes, characteristic of many species of this family, are absent. The essential oils from the species of the genus Phlomis have been much more widely studied than the secretory structures. They show considerable variability depending on the species and the environmental conditions. Full article

Inoculation with rhizobacteria and feeding by herbivores, two types of abiotic stress, have been shown to increase the production of secondary metabolites in plants as part of the defense response. This study explored the simultaneous effects of inoculation with Bacillus amyloliquefaciens GB03 (a PGPR species) and herbivory by third-instar Spodoptera frugiperda larvae on essential oil (EO) yield and volatile organic compound (VOC) emissions in Ocimum basilicum plants. The density of glandular trichomes was also examined, given that they are linked to EO production and VOC emission. Herbivory increased EO content, but inoculation on its own did not. When combined, however, the two treatments led to a 10-fold rise in EO content with respect to non-inoculated plants. VOC emissions did not significantly differ between inoculated and non-inoculated plants, but they doubled in plants chewed by the larvae with respect to their undamaged counterparts. Interestingly, no changes were observed in VOC emissions when the treatments were tested together. In short, the two biotic stressors elicited differing plant defense responses, mainly when EO was concerned. PGPR did not stimulate EO production, while herbivory significantly enhanced it and increased VOC emissions. The combined treatment acted synergistically, and in this case, PGPR inoculation may have had a priming effect that amplified plant response to herbivory. Peltate trichome density was higher in inoculated plants, those damaged by larvae, and those subjected to the combination of both treatments. The findings highlight the intricate nature of plant defense mechanisms against various stressors and hint at a potential strategy to produce essential oil through the combined application of the two stressors tested here. Full article

Cannabaceae species garner attention in plant research due to their diverse secretory structures and pharmacological potential associated with the production of secondary metabolites. This study aims to update our understanding of the secretory system in Hops (Humulus lupulus L.), an economically important species especially known for its usage in beer production. For that, stems, leaves, roots, and inflorescences were collected and processed for external morphology, anatomical, histochemical, ultrastructural and cytochemical analyses of the secretory sites. Our findings reveal three types of secretory structures comprising the secretory machinery of Hops: laticifer, phenolic idioblasts and glandular trichomes. The laticifer system is articulated, anastomosing and unbranched, traversing all plant organs, except the roots. Phenolic idioblasts are widely dispersed throughout the leaves, roots and floral parts of the species. Glandular trichomes appear as two distinct morphological types: capitate (spherical head) and peltate (radial head) and are found mainly in foliar and floral parts. The often-mixed chemical composition in the secretory sites serves to shield the plant from excessive UVB radiation, elevated temperatures, and damage inflicted by herbivorous animals or pathogenic microorganisms. Besides the exudate from peltate glandular trichomes (lupulin glands), latex and idioblast content are also likely contributors to the pharmacological properties of different Hop varieties, given their extensive presence in the plant body. Full article

Origanum vulgare, belonging to the Lamiaceae family, is a principal culinary herb used worldwide which possesses great antioxidant and antibacterial properties corresponding to various volatile organic components (VOCs). However, the metabolite profiles and underlying biosynthesis mechanisms of elaborate tissues (stems, leaves, bracts, sepals, petals) of Origanum vulgare have seldom been reported. Here, solid-phase microextraction–gas chromatography/mass spectrometry results showed that Origanum vulgare ‘Hot and Spicy’ (O. vulgare ‘HS’) was extremely rich in carvacrol and had the tissue dependence characteristic. Moreover, a full-length transcriptome analysis revealed carvacrol biosynthesis and its tissue-specific expression patterns of ‘upstream’ MVA/MEP pathway genes and ‘downstream’ modifier genes of TPSs, CYPs, and SDRs. Furthermore, the systems biology method of modular organization analysis was applied to cluster 16,341 differently expressed genes into nine modules and to identify significant carvacrol- and peltate glandular trichome-correlated modules. In terms of these positive and negative modules, weighted gene co-expression network analysis results showed that carvacrol biosynthetic pathway genes are highly co-expressed with TF genes, such as ZIPs and bHLHs, indicating their involvement in regulating the biosynthesis of carvacrol. Our findings shed light on the tissue specificity of VOC accumulation in O. vulgare ‘HS’ and identified key candidate genes for carvacrol biosynthesis, which would allow metabolic engineering and breeding of Origanum cultivars. Full article

Euphorbiaceae and Phyllantaceae are two of the most taxonomically complex and diverse families among angiosperm. Therefore, this study aims to identify the common, variation, and diagnostic traits of foliar anatomy and micromorphology of selected Euphorbiaceae and Phyllanthaceae taxa collected from Hainan Island. A total of 42 individuals of 38 species belonging to these two families were examined under light microscopy (LM) and scanning electron microscopy (SEM). A multivariate detrended correspondence analysis (DCA), principal component analysis (PCA), and chord diagram analysis were performed to visualize the variations and relationships between the species. The nonglandular trichomes were further classified into long falcate and short conical with papillae on their surface, and stellate and lepidote subentire, while the glandular trichomes were divided into capitate, subsessile capitate, sessile capitates, and peltate. The paracytic-type stomata were found in most of the species. The prominent continuous or discontinuous cuticular striations radiating from the guard cells in parallel, horizontal, or reticulate patterns were analyzed in most of the taxa. Variation was also found in epidermal cells and anticlinal wall patterns. Together, these traits are useful for identification, discrimination, and to define species boundaries at various levels. Our study will provide a basis for future studies to strengthen the systematic of Euphorbiaceae taxa. Full article

Chrysanthemum is a popular ornamental plant with a long history of cultivation. Both the leaf and flowerhead of Chrysanthemum are known to produce diverse secondary metabolites, particularly terpenoids. Here we aimed to determine the relationship between terpene chemistry and the trichome traits in Chrysanthemum. In our examination of three cultivars of C. morifilium and three accessions of C. indicum, all plants contained T-shaped trichomes and biseriate peltate glandular trichomes. The biseriate peltate glandular trichome contained two basal cells, two stalk cells, six secondary cells and a subcuticular space, while the non-glandular T-shaped trichome was only composed of stalk cells and elongated cells. Histochemical staining analysis indicated that the biseriate peltate glandular trichome contained terpenoids and lipid oil droplets but not the T-shaped trichome. Next, experiments were performed to determine the relationship between the accumulation and emission of the volatile terpenoids and the density of trichomes on the leaves and flowerheads in all six Chrysanthemum cultivars\accessions. A significant correlation was identified between the monoterpenoid and sesquiterpenoid content and the density of glandular trichomes on the leaves, with the correlation coefficients being 0.88, 0.86 and 0.90, respectively. In contrast, there was no significant correlation between the volatile terpenoid content and the density of T-shaped trichomes on the leaves. In flowerheads, a significant correlation was identified between the emission rate of terpenoids and the number of glandular trichomes on the disc florets, with a correlation coefficient of 0.95. Interestingly, the correlation between the density of glandular trichomes and concentrations of terpenoids was insignificant. In summary, the relationship between trichomes and terpenoid chemistry in Chrysanthemum is clearly established. Such knowledge may be helpful for breeding aromatic Chrysanthemum cultivars by modulating the trichome trait. Full article

In the extreme north of Chile, the genus Tillandsia L. (Bromeliaceae) is represented by three native species, T. marconae Till & Vitek and T. landbeckii Phil., both of terrestrial atmospheric habit, and T. virescens Ruiz & Pav. of saxicolous habit. There is little information on the foliar structures that allow its establishment in arid environments. Therefore, we studied the leaf anatomy of each of these terrestrial and saxicolous atmospheric species from different altitudinal levels (1000 and 3000 m) in the Arica and Parinacota regions of the Atacama Desert. All populations are monospecific. The study considered scanning electron microscopy, optical microscopy, and the fingernail polish technique. The surface distribution of stomata and trichomes of the species is described. The studied species presented hypostomatic leaves, with anomocytic stomata and peltate trichomes on the abaxial and adaxial sides. Trichomes are formed by a central disc of four equal-sized empty cells, surrounded by a peripheral series of several concentric rings, the innermost of eight, the second of sixteen and the outermost of multiple elongated cells, one cell thick, that form the flexible asymmetric wings. The number of wing cells varies according to the species. Trichomes are evenly arranged in long lanceolate leaf blades with smooth margins. Full article

Several species of fungi from the orders Chaetothyriales and Pleosporales have been reported to produce swainsonine and be associated as symbionts with plants of the Convolvulaceae and Fabaceae, respectively. An endosymbiont belonging to the Chaetothyriales produces swainsonine and grows as an epibiont on the adaxial leaf surfaces of Ipomoea carnea, but how the symbiont passes through plant growth and development is unknown. Herein, different types of microscopy were used to localize the symbiont in seeds and in cross sections of plant parts. The symbiont was found in several tissues including the hilum, the sclereids, and the hypocotyl of seeds. In five-day old seedlings and mature plants, the symbiont was found in the shoot apical meristem (SAM) and the adaxial surface of immature folded leaves. The mycelia generally formed a close association with peltate glandular trichomes. This report provides further data explaining the relationship between the seed transmitted Chaetothyriales symbiont and Ipomoea carnea. These results provide a possible explanation for how this symbiont, and others like Periglandula may persist and are transmitted over time. Full article