Search Results (351)

Urban expansion alters environmental conditions, influencing tree physiology and performance. Urban trees provide cooling, sequester carbon, support biodiversity, filter contaminants, and enhance human health. This study examines how two common urban trees—Norway Maple (Acer platanoides L.) and Little-leaved Linden (Tilia cordata Mill.)—respond to urban site conditions by assessing leaf morphology, stomatal, and gas exchange traits across street and urban park sites in Chicago, IL. Street trees exhibited structural trait adjustments, including smaller leaf area, reduced specific leaf area, and increased stomatal density, potentially reflecting acclimation to more compact and impervious conditions. Norway Maple showed stable photosynthetic assimilation (A), stomatal conductance (g_s), and transpiration (E) across sites, alongside higher intrinsic water-use efficiency (_iWUE), indicating a conservative water-use strategy. In contrast, Little-leaved Linden maintained A and g_s but showed elevated E and _iWUE at street sites, suggesting adaptive shifts in water-use dynamics under street microenvironments. These findings highlight how species-specific physiological strategies and local site conditions interact to shape tree function in cities and underscore the importance of incorporating functional traits into urban forestry planning to improve ecosystem services and climate resilience. Full article

Stomata on the leaves of wheat serve as important gateways for gas exchange with the external environment. Their morphological characteristics, such as size and density, are closely related to physiological processes like photosynthesis and transpiration. However, due to the limitations of existing analysis methods, the efficiency of analyzing and mining stomatal phenotypes and their associated genes still requires improvement. To enhance the accuracy and efficiency of stomatal phenotype traits analysis and to uncover the related key genes, this study selected 210 wheat varieties. A novel semantic segmentation model based on transformer for wheat stomata, called Wheat Stoma Former (WSF), was proposed. This model enables fully automated and highly efficient stomatal mask extraction and accurately analyzes phenotypic traits such as the length, width, area, and number of stomata on both the adaxial (Ad) and abaxial (Ab) surfaces of wheat leaves based on the mask images. The model evaluation results indicate that coefficients of determination (R²) between the predicted values and the actual measurements for stomatal length, width, area, and number were 0.88, 0.86, 0.81, and 0.93, respectively, demonstrating the model’s high precision and effectiveness in stomatal phenotypic trait analysis. The phenotypic data were combined with sequencing data from the wheat 660 K SNP chip and subjected to a genome-wide association study (GWAS) to analyze the genetic basis of stomatal traits, including length, width, and number, on both adaxial and abaxial surfaces. A total of 36 SNP peak loci significantly associated with stomatal traits were identified. Through candidate gene identification and functional analysis, two genes—TraesCS2B02G178000 (on chromosome 2B, related to stomatal number on the abaxial surface) and TraesCS6A02G290600 (on chromosome 6A, related to stomatal length on the adaxial surface)—were found to be associated with stomatal traits involved in regulating stomatal movement and closure, respectively. In conclusion, our WSF model demonstrates valuable advances in accurate and efficient stomatal phenotyping for locating genes related to stomatal traits in wheat and provides breeders with accurate phenotypic data for the selection and breeding of water-efficient wheat varieties. Full article

Stomata play a crucial role in plant immune responses, with their morphological characteristics closely linked to disease resistance. Accurate detection and analysis of stomatal phenotypic parameters are essential for soybean disease resistance research and variety breeding. However, traditional stoma detection methods are challenged by complex backgrounds and leaf vein structures in soybean images. To address these issues, we proposed a Soybean Stoma-YOLO (You Only Look Once) model (SS-YOLO) by incorporating large separable kernel attention (LSKA) in the Spatial Pyramid Pooling-Fast (SPPF) module of YOLOv8 and Deformable Large Kernel Attention (DLKA) in the Neck part. These architectural modifications enhanced YOLOV8′s ability to extract multi-scale and irregular stomatal features, thus improving detection accuracy. Experimental results showed that SS-YOLO achieved a detection accuracy of 98.7%. SS-YOLO can effectively extract the stomatal features (e.g., length, width, area, and orientation) and calculate related indices (e.g., density, area ratio, variance, and distribution). Across different soybean rust disease stages, the variety Dandou21 (DD21) exhibited less variation in length, width, area, and orientation compared with Fudou9 (FD9) and Huaixian5 (HX5). Furthermore, DD21 demonstrated greater uniformity in stomatal distribution (SEve: 1.02–1.08) and a stable stomatal area ratio (0.06–0.09). The analysis results indicate that DD21 maintained stable stomatal morphology with rust disease resistance. This study demonstrates that SS-YOLO significantly improved stoma detection and provided valuable insights into the relationship between stomatal characteristics and soybean disease resistance, offering a novel approach for breeding and plant disease resistance research. Full article

Ginseng (Panax ginseng) is highly sensitive to heat stress caused by climate change; thus, the introduction of heat-tolerant cultivars is essential. However, the stable dissemination of heat-tolerant cultivars remains limited due to low propagation efficiency. Plant tissue culture has been introduced as an alternative approach, yet in vitro-grown ginseng often exhibit low survival rates during acclimatization, thereby restricting their practical application. This study was conducted as a fundamental investigation to address this limitation by comparing the morphological, histological, physiological, and metabolic differences between ginseng plants grown in vitro and ex vitro. The results demonstrated that in vitro-grown ginseng had stems and roots that were approximately 30% shorter, less prominent taproot development, and more than 30% lower root fresh weight. These plants also contained about 50% lower chlorophyll content and 52% higher stomatal density compared with ex vitro-grown ginseng. Histologically, in vitro plants exhibited narrow intercellular spaces, underdeveloped root cambium, and lignin deposition in cell walls. Metabolically, in vitro-grown ginseng was clearly distinguishable based on ginsenoside content and volatile compound profiles. The comprehensive findings of this study provide baseline information for future research and can be utilized to enhance the practicality of tissue culture-based micropropagation of ginseng. Full article

Spring droughts, increasingly coinciding with canopy shade, interactively stress the growth of urban tree species and are poorly understood in Beijing. Three-year-old saplings of Pinus tabuliformis and Robinia pseudoacacia were subjected to comparative analysis under four drought–shade sequences, with a full-light, well-watered treatment serving as the control. During two periods encompassing the drought to wilting point and subsequent rewatering, we assessed leaf morphology, water status, photosynthetic gas exchange, and chlorophyll fluorescence. Both species exhibited losses in leaf water and carbon assimilation under drought, yet their adaptive strategies substantially differed. P. tabuliformis conserved water through the stable leaf anatomy and conservative stomatal control. In particular, P. tabuliformis under full-light and drought conditions decreased their specific leaf area (SLA) by 23%, as well as showing reductions in stomatal conductance (G_s) and transpiration rate (T_r) along with the drought duration (p < 0.01). As the duration of post-drought rewatering increased, the reductions in the net photosynthetic rates (P_n) of P. tabulaeformis showed that the shade condition intensified its photosynthetic limitation and slowed recovery after drought. Under low-light drought, R. pseudoacacia exhibited a 52% increase in SLA and a 77% decline in G_s; the latter was markedly smaller than the reduction observed under full-light drought. After rewatering, G_s displayed an overcompensation response. The rise in specific leaf area and the greater flexibility of stomatal regulation partly offset the adverse effects of drought. Nevertheless, post-drought P_n recovered to only 40%, significantly lower than the 61% recovery under full-light drought. Moreover, the negative correlation between SLA and P_n became significantly stronger, indicating that the “after-effects” of shade–drought hindered photosynthetic recovery once the stress was relieved. Drought duration eroded the phenotypic performance in both species, while the light environment during drought and subsequent rehydration determined the time trajectory and completeness of recovery. These results validate a trade-off between shade mitigation and drought legacy, and guide species selection: plant shade-tolerant R. pseudoacacia in light-limited urban pockets and reserve sun-dependent P. tabuliformis for open, high-light sites to enhance drought resilience of Beijing’s urban forests. Full article

This study investigated the effects of the foliar application of sodium silicate (SS) on phytolith formations in Dendrocalamus brandisii (Munro) Kurz. leaves by analyzing the phytolith concentration, morphological parameters, and assemblage compositions across leaves of varying ages and different phenological stages. The results showed that SS significantly increased the phytolith concentration in D. brandisii leaves, showing a trend of old leaves > mature leaves > young leaves. The concentration of phytoliths was the highest at the late shooting stage (November) and the lowest at the dormancy stage (January). August (shooting stage) and May (branching and leafing stage) were the critical periods for phytolith formation and the size and morphological variation. Sodium silicate significantly increased the proportion of saddle, bilobate, and stomatal phytoliths, which might help optimize the silicified structure of leaf epidermal cells and enhance the leaf resistance and light energy utilization efficiency. The results help clarify the mechanism of phytolith formation in different phenological periods of D. brandisii and provide a theoretical basis for the efficient use of silicon fertilizers in bamboo cultivation. Full article

The aim of this study was to determine the possibilities of using cold-plasma technology in counteracting the development of denture stomatitis (DS) in patients using different kinds of prosthetic restorations. The study focused mainly on the effect of cold atmospheric plasma on prosthetic materials, such as acryl (AR), acetal (AT), and a prosthetic metal alloy (MA). The materials were tested in terms of the effect of the plasma exposure time (5, 10, and 20 min) on changes in the chemical composition, morphology, and surface topography (FT-IR, SEM-EDS, optical profilometer) as well as changes in the color and contact angle (spectrophotometer, goniometer) after the plasma process. Furthermore, the ability of reference fungi (C. albicans and C. glabrata) to adhere to non-modified and cold atmospheric plasma (CAP)-modified dental materials was examined to evaluate the susceptibility of dental material surfaces to 12 h fungal contamination. The obtained results demonstrate that CAP appears viable for the surface modification of the acetal resin and the metal alloy, not compromising their structural integrity while variably limiting fungal overgrowth involved in the development of DS, whereas its application to the acrylic resin may be inadvisable due to morphological and optical alterations. Full article

As low temperature is a key factor affecting the growth and development of plants and the utilization of agricultural waste has significant research value, this study explores the effects of 16 agricultural wastes on the growth of P. fraseri under natural low-temperature conditions and evaluates its cold resistance capacity. Soil chemical properties were analyzed and all the wastes were found to exhibit alkalinity. The highest total nitrogen content was found in group A (garden soil/coir/municipal sludge = 7:1:2). In this group, the branch number, branch length, and branch diameter were the largest. Interestingly, the plants in group E (garden soil/coir/pig manure = 7:1:2) had the highest average number of new shoots, with 5.72. Analysis of the physiological indexes of leaves revealed that the proline content, superoxide dismutase activity, fresh weight, and dry weight of plants in group L (garden soil/coir/pear residue = 7:1:2) were the highest. The stomatal conductance and transpiration rate of the leaves of plants in group L were the largest, at 86.23 mmol∙m⁻²∙s⁻¹ and 1.67 mmol∙m⁻²∙s⁻¹, respectively. Furthermore, combined with morphological and physiological indicators for membership function analysis, the results show that plants in group A exhibited optimal growth under natural low temperature. Correlation analysis indicated varying degrees of correlation between 38 pairs of indicators, including branch number and branch length, intercellular CO₂ concentration and stomatal conductance, and leaf fresh weight and dry weight. Heatmap analysis showed that branch number, branch length, and branch diameter were highest in group A plants, while the highest levels of proline occurred in group L plants. In this study, groups A and L are recommended for growth under naturally low-temperature conditions. Full article

Background/Objectives: Ecballium elaterium is a widely distributed species and is one of the earliest recorded in traditional medicine. With global temperatures rising, this study aimed to investigate the changes in E. elaterium plantlets subjected to thermal stress. The goal was to understand how thermal stress affects morphology, physiology, and bioactive metabolite production, both for ecological adaptation and potential therapeutic applications. Methods: Seedlings were cultivated under controlled conditions and subjected to either the control temperature (22 °C) or the heat stress temperature (35 °C) for one week. Morphological and anatomical traits were assessed, along with physiological parameters such as chlorophyll content, malondialdehyde (MDA), hydrogen peroxide (H₂O₂), L-proline, soluble sugars, and total phenolic content. Methanolic leaf extracts from both groups were analyzed via LC-HRMS/MS and examined in vitro for cytotoxic activity against three human cancer cell lines: MCF-7 (breast), DU-145 (prostate), and SH-SY5Y (neuroblastoma). Results: Heat stress reduced dry mass and stomatal density but increased the diameter of the root transition zone, indicating anatomical adaptation. Leaves exhibited elevated oxidative stress markers and altered metabolite accumulation, while the roots showed a more integrated stress response. LC-HRMS/MS profiling revealed significant shifts in Cucurbitacin composition. Extracts from heat-stressed plants displayed stronger cytotoxicity, particularly toward DU-145 and SH-SY5Y cells, correlating with higher levels of glycosylated Cucurbitacins. Conclusions: E. elaterium demonstrates organ-specific thermotolerance mechanisms, with heat stress enhancing the production of bioactive metabolites. These stress-induced phytochemicals, especially Cucurbitacins, hold promise for future cancer research and therapeutic applications. Full article

Veronica nakaiana Ohwi and Veronica pusanensis Y.N.Lee are rare and endemic plants native to Korea, with increasing interest in their cultivation and breeding for industrial applications. Mutation breeding is important for developing horticultural cultivars. Among mutation breeding techniques, chemical mutagenesis is particularly accessible and effective. Colchicine-induced mutagenesis was performed in vivo at various concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) and treatment durations (1, 2, 3, 4, and 5 h). Both V. nakaiana Ohwi and V. pusanensis Y.N.Lee showed the highest survival (23.4% and 34.8%, respectively) and mutation (1.6% and 0.5%, respectively) rates with 0.2% colchicine. Flow cytometry and chromosome number analyses revealed mutants as tetraploid, with chromosome numbers ranging from 2n = 66 to 2n = 68. Stomatal analysis indicated increased stomatal length and width and decreased stomatal density. Morphological analysis of the mutants revealed that the leaves of V. nakaiana Ohwi and V. pusanensis Y.N.Lee were significantly larger and had different shapes compared to the control. This study successfully generated new mutant plants of two Veronica species using chemical mutagen treatment, which could be utilized as new genetic resources for various Veronica species breeding programs in the future. Full article

In recent years, high temperature and drought have severely impacted the growth and development of loquat [Eriobotrya japonica (Thunb.) Lindl.] plants. Although dopamine can improve the stress resistance of plants, its role in combined stress requires further exploration. This study investigated the alleviative effect and mechanism of exogenous dopamine on loquat seedlings subjected to the combined stress of high temperature and drought. The combined stress significantly reduced root viability, photosynthetic pigment content, and net photosynthetic rate (Pn) while markedly increasing reactive oxygen species (ROS) levels, thiobarbituric acid-reactive substances (TBARS) content, and electrolyte leakage (EL). The seedlings exhibited pronounced wilting symptoms, along with markedly reduced root surface area and volume. Dopamine treatment significantly alleviated combined stress-induced damage. This mitigation was manifested through substantially enhanced root viability, photosynthetic pigment content, Pn, antioxidant enzyme activities, and osmotic adjustment substances concomitantly with marked reductions in ROS, TBARS content, and EL. Dopamine significantly reduced seedling wilting severity and improved root morphological parameters. This study demonstrates that dopamine enhances loquat seedlings’ tolerance to combined stress through coordinated mechanisms: maintaining photosynthetic pigments and improving stomatal conductance to sustain photosynthetic efficiency, enhancing antioxidant enzyme activity and ROS scavenging capacity to mitigate oxidative damage, and promoting osmotic solute accumulation for osmotic potential regulation. Full article

Schmallenberg virus (SBV) is a negative-sense RNA virus transmitted by insect vectors, causing arthrogryposis-hydranencephaly syndrome in newborn ruminants. Since its discovery in Germany and the Netherlands in 2011, SBV has rapidly spread across multiple European countries, resulting in significant economic losses in the livestock industry. With the increasing global animal trade and the expanded range of insect transmission, the risk of SBV introduction into non-endemic regions is also rising. As the gold standard for serological testing, the virus neutralization test (VNT) is crucial for tracking the spread of SBV and evaluating the efficacy of vaccines. However, in non-endemic regions, the lack of local viral strains and the biosafety risks associated with introducing foreign strains pose challenges to the implementation of VNT. In this study, we employed reverse genetics techniques using vesicular stomatitis virus (VSV) to substitute the VSV G protein with the envelope glycoproteins of SBV, thereby successfully generating and rescuing the recombinant virus rVSVΔG-eGFP-SBVGPC. The recombinant virus was then thoroughly characterized in terms of SBV Gc protein expression, viral morphology, and growth kinetics. Importantly, rVSVΔG-eGFP-SBVGPC exhibited SBV-specific cell tropism and was capable of reacting with SBV-positive serum, enabling the measurement of neutralizing antibody titers. The results suggest that this recombinant virus can serve as a feasible alternative for SBV neutralization tests, with promising potential for application in serological screening and vaccine evaluation. Full article

Chlorophyll biosynthesis is essential for photosynthesis and plant development. Disruptions in this pathway often manifest as pigment-deficient phenotypes. This study characterizes the morphological, anatomical, and physiological consequences of a chlorophyll-deficient rice mutant (yellow seedling, YS) caused by a loss-of-function mutation in the OsCHLI gene, which encodes the ATPase subunit of magnesium chelatase. Comparative analyses between YSs and wild-type green seedlings (GSs) revealed that YSs exhibited severe growth retardation, altered mesophyll structure, reduced xylem and bulliform cell areas, and higher stomatal and papillae density. These phenotypes were strongly light-dependent, indicating that OsCHLI plays a crucial role in light-mediated chloroplast development and growth. Transcriptome analysis further revealed global down-regulation of photosynthesis-, TCA cycle-, and cell wall-related genes, alongside selective up-regulation of redox-related pathways. These results suggest that chlorophyll deficiency induces systemic metabolic reprogramming, prioritizing stress responses over growth. This study highlights the multifaceted role of OsCHLI in plastid maturation, retrograde signaling, and developmental regulation, providing new insights for improving photosynthetic efficiency and stress resilience in rice. Full article

Drought stress limits seedling growth, hindering morphological development and population establishment. Artocarpus nanchuanensis, a critically endangered species endemic to the karst regions of southwest China, exhibits poor population structure and limited natural regeneration in the wild, with water deficit during the seedling stage identified as a major factor contributing to its endangered status. Elucidating the physiological and molecular mechanisms underlying drought tolerance in A. nanchuanensis seedlings is essential for improving their drought adaptability and facilitating population recovery. In this study, 72 two-year-old seedlings were divided into two groups: drought (PEG) and ethephon (PEG + Ethephon), and subjected to drought-rehydration experiments. The results showed that exogenous application of 100 mg·L⁻¹ ethephon significantly improved stomatal conductance and photosynthetic pigment content in A. nanchuanensis seedlings. Under drought stress, the PEG + Ethephon group exhibited rapid stomatal closure, maintaining water balance and higher photosynthetic pigment levels. After rehydration, the PEG + Ethephon group significantly outperformed the PEG group in terms of photosynthetic rate. Ethephon treatment reduced H₂O₂ and MDA levels, enhanced antioxidant enzyme activity (SOD, CAT, POD, GR), and increased osmotic regulator activity (soluble sugars, soluble proteins, and proline), improving ROS-scavenging capacity and reducing oxidative damage. Ethephon application significantly enhanced ethylene accumulation in seedlings, while drought stress stimulated the concentrations of key ethylene biosynthetic enzymes (SAMS, ACS, and ACO), thereby further contributing to improved drought resistance. Transcriptomic data revealed that drought stress significantly upregulated key ethylene biosynthesis genes, with expression levels increasing with stress duration and rapidly decreasing after rehydration. WGCNA analysis identified eight key drought-resistance genes, providing valuable targets for future research. This study provides the first mechanistic insight into the physiological and molecular responses of A. nanchuanensis seedlings to drought and rehydration, underscoring the central role of endogenous ethylene in drought tolerance. Ethephon treatment effectively enhanced ethylene accumulation and biosynthetic enzyme activity, thereby improving drought adaptability. These findings lay a theoretical foundation for subsequent molecular functional studies and the conservation biology of this endangered species. Full article

Liriope muscari is a medicinal and ornamental herbaceous plant with significant economic value, as its tuberous roots are used for medicinal purposes. However, the current production of medicinal plants is characterized by wasteful use of resources and ecological risks caused by the unreasonable application of nitrogen fertilizers. In this study, based on uniform application of phosphorus and potassium fertilizers, six nitrogen application levels were set in pot experiments (expressed as N): N0: 0 kg/ha, N1: 208.33 kg/ha, N2: 416.66 kg/ha, N3: 625 kg/ha, N4: 833.33 kg/ha, N5: 1041.66 kg/ha). The morphological characteristics, photosynthetic physiology, tuber yield and quality, and seven nitrogen fertilizer utilization indices of L. muscari were analyzed and measured. Correlation analysis and structural equation modeling (SEM) were employed to investigate the mechanism by which nitrogen influences its growth and development, photosynthetic characteristics, tuber yield and quality, and nitrogen fertilizer utilization efficiency. The results showed that (1) nitrogen significantly promoted plant height, crown width, tiller number, and chlorophyll synthesis, with the N3 treatment (625 kg/ha) reaching the peak value, and the crown width and tiller number increasing by 26.44% and 38.90% compared to N0; the total chlorophyll content and net photosynthetic rate increased by 39.67% and 77.04%, respectively, compared to N0; high nitrogen (N5) inhibited photosynthesis and increased intercellular CO₂ concentration; (2) Fresh weight of tuberous roots, polysaccharide content, and saponin C content peaked at N3 (34.67 g/plant, 39.89%, and 0.21%), respectively, representing increases of 128.69%, 28.37%, and 33.66% compared to N0; (3) Nitrogen uptake, nitrogen fertilizer utilization efficiency, agronomic utilization efficiency, and apparent utilization efficiency were optimal at N3, while high nitrogen (N4–N5) reduced nitrogen fertilizer efficiency by 40–60%; (4) SEM analysis indicated that tiller number and transpiration rate directly drive yield, while stomatal conductance regulates saponin C synthesis. Under the experimental conditions, 625 kg/ha is the optimal nitrogen application rate balancing yield, quality, and nitrogen efficiency. Excessive nitrogen application (>833 kg/ha) induces photosynthetic inhibition and “luxury absorption”, leading to source-sink imbalance and reduced accumulation of secondary metabolites. This study provides a theoretical basis and technical support for the precise management of nitrogen in Liriope-type medicinal plants. It is expected to alleviate the contradictions of “high input, low output, and heavy pollution” in traditional fertilization models. Full article