Search Results (148)

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

The aim of this study was to evaluate whether intraspecific differences in zinc (Zn) tolerance and accumulation in the hyperaccumulator Noccaea caerulescens are linked to Zn-induced changes in transpiration and mineral composition. At 500 µM Zn in the nutrient solution, a decrease in the root and shoot biomass, the water content in roots, and the contents of photosynthetic pigments in shoots was observed only in the non-metallicolous population Wilwerwiltz, whereas in the calamine population Prayon, root growth was stimulated. Zinc-induced impairment of mineral nutrition was greater in Wilwerwiltz than in Prayon, which determined the manifestation of Zn toxicity in Wilwerwiltz. The absence of signs of Zn toxicity and the stimulation of root growth in Prayon may be due to lower Zn accumulation in Prayon than in Wilwerwiltz, as well as more effective mechanisms of Zn detoxification. The higher Zn content in the shoots and, in particular, in the water-storage cells of the leaf epidermis in Wilwerwiltz compared to Prayon may be partly due to the higher transpiration rate in Wilwerwiltz, at least at 500 µM Zn. These findings suggest that the metallicolous population maintains better control over Zn accumulation, which may be a part of the adaptive response to Zn-enriched media. Full article

The growing demand for sustainable phytosanitary products has renewed interest in botanical insecticides as viable pest control tools. Amid rising demand for sustainable crop protection, this study screens Cerrado plants traditionally used in medicine to pinpoint bioactive compounds that could replace synthetic pesticides. These products have complex chemical compositions, with compounds acting synergistically through multiple mechanisms, including oral (ingestion of allelochemicals) and topical (contact of allelochemicals on epidermis) toxicity. This study evaluated the oral and topical toxicity of aqueous leaf extracts from Anemopaegma arvense (AEAa), Coussarea hydrangeifolia (AECh), Tapirira guianensis (AETg), and Duguetia furfuracea (AEDf) on Plutella xylostella. In the oral toxicity test, first-instar larvae were fed treated diets until pupation, with biological parameters monitored until adulthood. The extracts caused an average of 45% larval mortality, reduced pupal duration, and lowered egg production. In the topical toxicity test, only the extract from T. guianensis showed significant effect (p = 0.0171), causing 30% mortality in third-instar larvae. The other extracts showed no significant topical toxicity, and AECh showed no lethal or sublethal effects at all. Phytochemical screening was assessed by quantitative spectrophotometric assays, and semi-quantitative classical colorimetric tests. Major compound classes identified were tannins, flavonoids, triterpenoids, coumarins, and alkaloids. These findings highlight the potential of the evaluated plant extracts for pest control, particularly via ingestion, while also underscoring the need for further studies to better understand their efficacy and mechanisms of action. Full article

Wild soybean (Glycine soja, GS) is a traditional medicine used to treat inflammation. In this study, the anti-atopic properties of GS leaf and stem extract on skin inflammation were evaluated in the Dermatophagoides farinae-extract-induced mouse model and keratinocytes. Oral administration of the GS extract reduced scratching, dermatitis score, transepidermal water loss, thickness of epidermis, inflammatory cell accumulation, and serum concentrations of thymic stromal lymphopoietin and immunoglobulin E. GS downregulated the expression of inflammatory gene markers of atopic dermatitis (AD), including interleukin (IL)-6; regulated on activation, normal T cell expressed and secreted (RANTES); thymus- and activation-regulated chemokine (TARC); and macrophage-derived chemokine (MDC) and upregulated the expression of filaggrin, a keratinocyte differentiation marker, in skin tissue. GS downregulated Janus kinase 1, signal transducer and activation of transcription (STAT) 1, and STAT3 pathways. Using ultra-performance liquid chromatography, we identified seven flavonoids in GS extract, including apigenin, epicatechin, genistein, genistin, daidzin, daidzein, and soyasaponin Bb. GS, apigenin, and genistein reduced the expression of IL-6, MDC, TARC, and RANTES and increased filaggrin via the downregulation of STAT3 phosphorylation in interferon-γ/tumor necrosis factor-α-stimulated keratinocytes. Our results suggest that GS leaf and stem extract ameliorates AD-like skin inflammation by regulating the immune response and restoring skin barrier function. Full article

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

‘Green island’ symptoms in the form of vivid green, round spots visible on the senescent leaves of many plants and trees are mostly the results of pathogenic colonization by fungi, and the greenish tissue is often dead. Therefore, this study investigates whether green spots observed on senescent Norway maple (Acer platanoides L.) leaves were still alive and photosynthetically active. The appearance of ‘green islands’ on the leaves of young Norway maple trees was observed from the autumn of 2019 to 2022 in an urban forest (Bialystok, eastern Poland). However, in the late summer (September) of 2023 and 2024, mostly tar spots caused by the fungus Rhytisma spp. on maple leaves could be observed, with only a few leaves having ‘green island’ symptoms. The percentage of ‘green island’ areas on senescent leaves observed during the 4 years (2019–2022) was influenced by a year of sampling (p < 0.001). A non-destructive physiological analysis of chlorophyll, flavonoids, and nitrogen balance index (NBI) in leaves revealed that these parameters were significantly lower in ‘green islands’ than in the summer leaves, but higher than in the senescent yellow area of the autumn leaves. In the case of anthocyanins, their level was significantly higher in ‘green islands’ than in yellow areas, although, in the summer leaves, anthocyanins were undetectable. The amount of chlorophyll and most photosynthetic parameters were significantly (p < 0.05) reduced in the ‘green islands’ of the senescent leaves compared to the mature green leaves. However, these parameters were significantly higher in the ‘green islands’ than in senescent yellow leaves. Carotenoid content in the ‘green island’ and yellow areas of senescent leaves were at the same level, twice as higher than in summer leaves. Green mature leaves and the ‘green islands’ on senescent leaves had the same structure and anatomy. The main differences concerned the chloroplasts, which were smaller and had less grana and starch grains, but had more plastoglobuli in ‘green island’ cells. The cells building the mesophyll in the yellow area of the leaf deteriorated and their chloroplasts collapsed. Epiphytes were present on the adaxial epidermis surface in all types of samples. Full article

Leaf anatomical traits are influenced by environmental and genetic factors; however, studies that investigate the genotype × environment interaction on these traits are scarce. This study hypothesized that (1) the leaf anatomy of Coffea spp. genotypes is varied, and (2) interactions between managements and seasons significantly influence leaf anatomical traits, inducing a clear adaptation to specific environments. Possible modifications of leaf anatomy in Coffea spp. genotypes were investigated under different managements: full-sun monoculture at low-altitude (MLA), full-sun monoculture at high altitude (MHA), and low-altitude agroforestry (AFS), in winter and summer. The genotype influenced all leaf anatomical traits investigated, contributing to 2.3–20.6% of variance. Genotype × environment interactions contributed to 2.3–95.8% of variance to key traits. The effects of genotype × management interactions were more intense than those of genotype × season interactions on traits such as leaf thickness, palisade parenchyma thickness, abaxial epidermis, and polar and equatorial diameter of the stomata. The management AFS was more effective in altering leaf anatomical traits than the altitude differences between MLA and MHA, regardless of the season. These findings provide valuable insights for future research and for the development of strategies to improve the adaptation of coffee plants to changing environmental conditions. Full article

Based on several sources of evidence from morphology, the micromorphology of the abaxial leaf epidermis, and a phylogenetic analysis using complete chloroplast genome data, a new combination and two new synonyms are reported in the genus Indocalamus Nakai. Indocalamus cordatus T. H. Wen et Y. Zou is synonymized with I. tessellatus (Munro) P. C. Keng, and I. chebalingensis W. T. Lin is synonymized with I. multinerus (W. T. Lin et Z. M. Wu) W. T. Lin. As a new combination, I. mollis (H. R. Zhao et Y. L. Yang) L. Q. Gao, W. G. Zhang et G. Y. Yang was created and is supplementally described. In addition, the lectotype of I. multinerus is designated herein. Full article

TCP transcription factors have long been known to play a crucial role in leaf development, but their significance in reproduction has recently been revealed. TCP5 is a member of class II of the TCP family, which predominantly regulates cell differentiation. This study used overexpression and SRDX fusion to evaluate the role of TCP5 in anther development. TCP5 overexpression resulted in lower fertility, primarily due to anther non-dehiscence. We also observed reduced lignin accumulation in the anther endothecium. In addition, TCP5 overexpression resulted in smaller anthers with fewer pollen sacs and pollen due to early-anther defects before meiosis. TCP5 showed expression in early anthers, including the epidermis, endothecium, middle layer, tapetum, sporogenous cells (pollen mother cells), and vascular bundles. Conversely, during meiosis, the TCP5 signal was only detected in the tapetum, PMCs, and vascular bundles. The TCP5 signal disappeared after meiosis, and no signal was observed in mature anthers. Interestingly, the TCP5-SRDX transgenic plants were also sterile, at least for the early-arising flowers, if not all of them. TCP5-SRDX expression also resulted in undersized anthers with fewer pollen sacs and pollen. However, the lignin accumulation in most of these anthers was comparable to that of the wild type, allowing these anthers to open. The qRT-PCR results revealed that several genes associated with secondary cell wall thickening had altered expression profiles in TCP5 overexpression transgenics, which supported the non-dehiscent anther phenotype. Furthermore, the expression levels of numerous critical anther genes were down-regulated in both TCP5 overexpression and TCP5-SRDX plants, indicating a comparable anther phenotype in these transgenic plants. These findings not only suggest that an appropriate TCP5 expression level is essential for anther development and plant fertility, but also improve our understanding of TCP transcription factor functioning in plant male reproduction and contribute information that may allow us to manipulate fertility and breeding in crops. Full article

Within the Rubiaceae family, the genus Randia comprises approximately 90 species, with significant morphological diversity in growth forms, leaf shapes, and floral sexuality. In particular, Randia aculeata is a taxonomically challenging species distributed from the southern United States to South America and the Antilles that exhibits high morphological variability and ecological adaptability. One of its synonyms is Randia tomatillo, originally described from coastal dunes in Veracruz, Mexico, and it has been inconsistently described in the taxonomic literature either as a distinct species or as a synonym for R. aculeata. This study aimed to resolve the taxonomic identity of R. tomatillo through morphological observations from herbarium specimens, and transverse sections from mature leaves were observed using SEM microscopy to explore crystal types. Morphological traits, such as lifeform, twig pubescence, stipule persistence, fruit size, and pericarp texture, are critical in distinguishing R. tomatillo from morphologically related species, such as R. aculeata and Randia thurberi. Anatomical features, particularly the presence of prisms in the leaf mesophyll and epidermis, are unique to R. tomatillo, suggesting their diagnostic value. Ecological adaptations, such as scandent growth and spongy pericarps for hydrochorous fruit dispersal, further support its distinction as a species adapted to coastal environments. These findings highlight the need for a comprehensive taxonomic reassessment of Randia, integrating morphological, anatomical, and ecological evidence. Full article

Morphological and micro-morphological traits of characteristics serve as the cornerstone for species identification and taxonomy, and they also ensure the adaptive responses of species to specific environmental conditions. Allium prattii C.H. Wright is mainly distributed in the mountains of southwestern China (MSC) and adjacent regions, and exhibits pronounced variations in leaf morphology and micro-morphology across different growth environments, making it an ideal taxa to study species adaptation to diverse conditions. In this study, we conducted extensive field surveys, sample collections, and morphological experiments, amassing data on leaf morphological and micro-morphological traits from 45 populations of A. prattii. Specifically, we explored the differences in leaf morphology among populations and the patterns of geographical distribution. Consequently, we examined the correlation between seven climatic factors, longitude, latitude, and leaf morphological traits, and simulated the changes in the A. prattii distribution area during different historical periods. Our results indicate that all populations of A. prattii can be categorized into four distinct lineages, characterized by significant leaf morphological divergence and distinct geographical distribution patterns. Populations located in the Hengduan Mountains and neighboring regions demonstrated elevated coefficients of variation (CV) in leaf morphology. The correlation analysis between morphological traits and climatic factors highlighted substantial links between the density of stomata on the upper epidermis and environmental variables, as well as significant correlations between leaf length/width and geographical distribution (latitude and longitude). Simulations of the distribution area revealed that the distribution ranges of A. prattii underwent a significant fluctuation from the Last Interglacial Period (LIG) to the Last Glacial Maximum (LGM), the Mid-Holocene (MH), and the current period, accompanied by expansion of its potential distribution area in the future. These results underscore that the leaf morphology of A. prattii has significantly varied in response to climatic environmental factors across different regions, with a decrease in leaf width and an increase in stomatal density on the upper epidermis. The heterogeneous environment of the southwestern mountain region, characterized by variations in altitude, temperature, and precipitation, is the primary driver of morphological variation and geographical distribution patterns in A. prattii leaves. Our findings hold substantial scientific significance, shedding light on the evolutionary adaptation of species in the MSC and adjacent areas. Full article

Soil contamination linked to anthropogenic activities has become a serious environmental problem on a global scale. It is caused by heavy metals, such as lead (Pb). Dopamine (DOP) is a biogenic amine that acts as a neurotransmitter. It is found in plant organs and induces tolerance against abiotic stresses, including contamination. 24-epibrassinolide (EBR) stimulates metabolism, positively impacting flowering and production. This research aimed to evaluate whether EBR and DOP, applied alone or combined, can mitigate the impacts caused by Pb on roots and leaves by measuring root and leaf structures and stomatal behavior. For roots, both plant growth regulators maximized the epidermis, with increases in treatments Pb²⁺ − DOP + EBR (45%), Pb²⁺ + DOP − EBR (24%), and Pb²⁺ + DOP + EBR (36%), when compared with equal treatment without Pb²⁺. To leaves, the tested molecules improved the leaf structures, significantly increasing palisade parenchyma and spongy parenchyma. Parallelly, stomatal performance was boosted after treatments with EBR and DOP, confirmed by increments in stomatal density. Our study proved that EBR and DOP, alone or combined, mitigated the damages to leaves and roots exposed to Pb stress, but better results were found when EBR was applied alone. Full article

This study investigates the effect of Serendipita indica inoculation on the growth, structural characteristics of leaf epidermis, photosynthetic parameters, and antioxidant and osmoregulation capacities of Agrostis stolonifera L. under different drought stresses (normal moisture management: at 70–75% of the field capacity, low drought: at 55–60% field capacity, moderate drought: at 40–45% of the field capacity, and severe drought: at 25–30% of the field capacity). The results showed that inoculation with S. indica significantly enhanced the growth potential of A. stolonifera compared to uninoculated controls, and then under drought stress conditions, inoculation with S. indica significantly alleviated the inhibition of the growth and development of A. stolonifera, especially under mild and moderate drought stresses. These improvements were evident in both aboveground and underground parts, leaf relative water content, total root length, and root surface area after 25 days of drought treatments. Inoculated plants also exhibited higher levels of photosynthetic pigments, net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) under drought conditions. Additionally, S. indica inoculation significantly increased the activities of catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), as well as the soluble sugar, soluble protein, and proline levels under drought-stressed and non-stressed conditions. In addition, the increases in the malondialdehyde (MDA) content and relative conductivity (RC) of leaves were significantly lower in the inoculated group compared to the control group. In conclusion, the symbiosis with S. indica promotes the growth of A. stolonifera under drought stress, likely by enhancing photosynthesis, osmoregulatory substances, and antioxidant enzyme activities. Full article

Drought stress is one of the main abiotic stresses that limit plant growth and affect fruit quality and yield. Plants primarily lose water through leaf transpiration, and wax effectively reduces the rate of water loss from the leaves. However, the relationship between water loss and the wax formation mechanism in goji (Lycium barbarum) leaves remains unclear. ‘Ningqi I’ goji and ‘Huangguo’ goji are two common varieties. In this study, ‘Ningqi I’ goji and ‘Huangguo’ goji were used as samples of leaf material to detect the differences in the water loss rate, chlorophyll leaching rate, wax phenotype, wax content, and components of the two materials. The differences in wax-synthesis-related pathways were analyzed using the transcriptome and metabolome methods, and the correlation among the wax components, wax synthesis genes, and transcription factors was analyzed. The results show that the leaf permeability of ‘Ningqi I’ goji was significantly lower than that of ‘Huangguo’ goji. The total wax content of the ‘Ningqi I’ goji leaves was 2.32 times that of the ‘Huangguo’ goji leaves, and the epidermal wax membrane was dense. The main components of the wax of ‘Ningqi I’ goji were alkanes, alcohols, esters, and fatty acids, the amounts of which were 191.65%, 153.01%, 6.09%, and 9.56% higher than those of ‘Huangguo’ goji, respectively. In the transcriptome analysis, twenty-two differentially expressed genes (DEGs) and six transcription factors (TFs) were screened for wax synthesis; during the metabolomics analysis, 11 differential metabolites were screened, which were dominated by lipids, some of which, like D-Glucaro-1, 4-Lactone, phosphatidic acid (PA), and phosphatidylcholine (PE), serve as prerequisites for wax synthesis, and were significantly positively correlated with wax components such as alkanes by the correlation analysis. A combined omics analysis showed that DEGs such as LbaWSD1, LbaKCS1, and LbaFAR2, and transcription factors such as LbaMYB306, LbaMYB60, and LbaMYBS3 were strongly correlated with wax components such as alkanes and alcohols. The high expression of DEGs and transcription factors is an important reason for the high wax content in the leaf epidermis of ‘Ningqi I’ goji plants. Therefore, by regulating the expression of wax-synthesis-related genes, the accumulation of leaf epidermal wax can be promoted, and the epidermal permeability of goji leaves can be weakened, thereby reducing the water loss rate of goji leaves. The research results can lay a foundation for cultivating drought-tolerant goji varieties. Full article

Plant stomata play a crucial role in photosynthesis by regulating transpiration and gas exchange. Meanwhile, environmental cues can also affect the formation of stomata. Stomatal formation, therefore, is optimized for the survival and growth of the plant despite variable environmental conditions. To adapt to environmental conditions, plants open and close stomatal pores and even regulate the number of stomata that develop on the epidermis. There are great differences in the leaf structure and developmental origin of the cell in the leaf between Arabidopsis and grass plants. These differences affect the fine regulation of stomatal formation due to different plant species. In this paper, a comprehensive overview of stomatal formation and the molecular networks and genetic mechanisms regulating the polar division and cell fate of stomatal progenitor cells in dicotyledonous plants such as Arabidopsis and Poaceae plants such as Oryza sativa and Zea mays is provided. The processes of stomatal formation mediated by plant hormones and environmental factors are summarized, and a model of stomatal formation in plants based on the regulation of multiple signaling pathways is outlined. These results contribute to a better understanding of the mechanisms of stomatal formation and epidermal morphogenesis in plants and provide a valuable theoretical basis and gene resources for improving crop resilience and yield traits. Full article