Search Results (1,150)

Efficient micropropagation systems are essential for the large-scale production of uniform and high-quality plant material in aromatic species. In this study, the effects of gibberellic acid (GA₃; 1.4, 2.8, and 5.6 µM) and methyl jasmonate (MeJA; 2.2, 4.4, and 8.8 µM) were evaluated on the in vitro performance of Artemisia pontica across two successive subcultures. Morphological, physiological, and biochemical parameters were assessed, and the most effective treatment was further investigated through scanning electron microscopy (SEM) to evaluate leaf trichome characteristics. GA₃ treatments significantly enhanced shoot growth, shoot number, and relative growth rate, with the strongest response observed at 2.8 µM. This concentration also promoted higher chlorophyll content and antioxidant activity, indicating improved physiological status and metabolic performance of plantlets. In contrast, MeJA treatments, particularly at 8.8 µM, reduced growth performance and pigment accumulation, suggesting a less favorable physiological status for micropropagation. Multivariate analysis (PCA and hierarchical clustering) revealed a clear separation among treatments, with GA₃ at 2.8 µM associated with a coordinated increase in growth-related and antioxidant traits. SEM analysis showed that GA₃ influenced leaf epidermal structure, increasing the density of T-shaped, non-glandular trichomes and the diameter of glandular secreting trichomes, suggesting structural adjustments linked to metabolic activity. Overall, the results indicate that GA₃ at 2.8 µM represents the most effective supplementation under the tested conditions, promoting a balanced improvement in shoot proliferation, physiological performance, antioxidant activity, and selected structural traits. Full article

Magnesium (Mg) deficiency is common in acidic orchard soils and can limit fruit crop growth and quality. This study evaluated whether foliar-applied magnesium oxide nanoparticles (MgO NPs) could improve Mg nutrition and fruit quality in ‘Ninghaibai’ loquat grown under Mg-deficient acidic soil conditions. Pot and field experiments were conducted using water as the control and MgSO₄-50eq as an equimolar Mg comparator. MgO NPs showed a concentration-dependent effect, and 200 mg/L produced the best overall performance among the tested concentrations. At this concentration, total biomass increased by 47.27%, compared with CK, accompanied by enhanced chlorophyll accumulation, antioxidant enzyme activities, and Mg uptake. In fruit, 200 mg/L MgO NPs increased soluble solids content by 45.67% and reduced titratable acidity by 53.26%, while also improving fruit size and sugar–acid balance. Leaf transcriptome analysis suggested that MgO NPs altered the expression of genes involved in metabolism, stress response, and secondary metabolite biosynthesis. At the 50 mg/L level, MgO NPs produced stronger responses than the equimolar MgSO₄ treatment in Mg uptake, nutrient acquisition, and several fruit-quality traits. However, excessive application at 500 mg/L weakened growth and quality improvement. Overall, foliar application of 200 mg/L MgO NPs may represent a promising strategy for improving loquat growth and fruit quality under the tested Mg-deficient conditions. Full article

Microplastics (MPs) and pesticides increasingly co-occur in agricultural ecosystems, where they may jointly affect plant physiology and plant–microorganism interactions. This study investigated the individual and combined effects of biodegradable poly(butylene adipate-co-terephthalate) (PBAT), the herbicide metolachlor (MET), and the beneficial fungus Trichoderma harzianum KKP 534 on wheat (Triticum aestivum). Plant growth, physiological responses, chlorophyll content, cell membrane damage, antioxidant enzyme activities and selected metabolomic and lipidomic biomarkers were evaluated. High PBAT concentrations negatively affected wheat growth by reducing root and shoot length and increasing oxidative stress, as evidenced by elevated TBARS levels, increased antioxidant enzyme activities (POD, GST, CAT, and SOD), and enhanced membrane damage. Metabolomic and lipidomic analyses further revealed stress-associated changes in amino acid metabolism and membrane lipid remodelling. PBAT also adsorbed MET and 2,4-di-tert-butylphenol (DTBP), potentially altering their bioavailability and environmental behaviour. Although T. harzianum KKP 534 promoted plant growth and enhanced antioxidant responses under control conditions, these beneficial effects were attenuated in the presence of PBAT MP. The results suggest that biodegradable microplastics may influence plant–microbe interactions and modify pesticide dynamics under controlled conditions, highlighting the need for further studies in soil-based systems. Full article

Quercuschenii Nakai is an ecologically and economically valuable tree species in China, but systematic research on container seedling cultivation is lacking. An optimal substrate mixture is critical for producing high-quality seedlings. A {4,3} simplex centroid mixture design was used to prepare 15 substrate mixtures combining peat, yellow subsoil, sawdust, and rice husk. Growth parameters, root morphology, biomass accumulation, and physiological indices of container seedlings were measured. Principal component analysis (PCA) and membership function method were applied for comprehensive evaluation, while substrate costs were also considered. Treatment T3 (20% peat + 80% yellow subsoil) produced the highest seedling height (59.3 cm), ground diameter (4.13 mm), total fresh weight (8.83 g), total dry weight (4.04 g), chlorophyll content (48.18 SPAD), soluble sugar (4.29 mg·g⁻¹), and soluble protein (23.62 mg·g⁻¹). PCA and membership function ranking showed T3 (0.88), T1 (100% yellow subsoil, 0.71), and T6 (60% peat + 40% yellow subsoil, 0.70) as the top three treatments. Bulk density of substrates ranged from 0.17 to 1.14 g·cm⁻³, and costs from 72.6 to 383.2 CNY·m⁻³. T3 had a bulk density of 0.89 g·cm⁻³ and cost 246.7 CNY·m⁻³, representing the best overall performance. The T3 mixture (20% peat + 80% yellow subsoil) provides moderate bulk density and cost, significantly promotes growth and physiological metabolism of Q. chenii seedlings, and is recommended as the optimal substrate for production. Full article

Reliance on mineral fertilization in papaya cultivation raises sustainability concerns and drives demand for validated organic alternatives. This study tested whether integrating humic substances (HS) and sugarcane filter cake (FC) would stimulate photosynthetic physiology, upregulate carbon metabolism gene expression, and increase fruit yield in ‘Golden’ papaya while outperforming conventional NPK fertilization. A 12-month field experiment was conducted in a randomized complete block design with a factorial arrangement of four HS doses (0, 90, 180, and 270 mL plant⁻¹) combined with two FC doses (0 and 60 kg plant⁻¹) plus an NPK control, measuring photosynthetic pigments, gas exchange, relative expression of rbcL, ACC oxidase, invertase, relative growth rate, and fruit yield. Combined HS and FC increased chlorophyll a by up to 205%, chlorophyll b by 277%, and carotenoids by 208% relative to unamended controls. Gene expression was strongly induced: rbcL reached 202-fold, invertase 156-fold, and ACC oxidase 84.8-fold above control values. Photosynthetic rate followed a quadratic dose-response peaking near 90 mL plant⁻¹ HS. Fruit yield nearly doubled under the optimal combined treatment (115 t ha⁻¹) compared with unamended controls (62 t ha⁻¹) and NPK fertilization (66 t ha⁻¹). These results confirm that HS and FC act synergistically as dual-purpose amendments, improving soil fertility while biostimulating papaya physiology through coordinated upregulation of photosynthetic capacity and carbon partitioning toward reproductive sinks. Full article

Despite the economic and medicinal value of the tree species Litsea mollis in southern China’s mountain forests, its wild populations remain understudied in terms of their adaptation to altitudinal gradients. This study examined L. mollis populations spanning altitudes of 760–1550 m in Nanshan Park, Hunan Province, to evaluate variation in leaf traits and fruit quality with elevation changes as well as associations with soil chemical properties. Results revealed that increasing altitude corresponded with higher leaf mass, chlorophyll content, soluble compound levels, enzyme activity, and various fruit quality traits (e.g., longitudinal and transverse diameters, weight, and fat, protein, carbohydrate, vitamin A, essential oil, and citral levels). Conversely, leaf area, specific leaf area, petiole length, fruit shape index, fruit stalk length, and ash content declined as altitude rose. Redundancy analysis indicated that specific leaf area, peroxidase activity, and Malondialdehyde content are the primary leaf characteristics influencing fruit quality, and soil pH and total nitrogen, alkaline nitrogen, and available potassium levels were key chemical factors shaping ecological adaptation and fruit quality of L. mollis along the altitudinal gradient. Overall, L. mollis augments light capture and nutrient acquisition by modifying morphological traits, such as leaf area (26.17%) and specific leaf area (44.32%), facilitating adaptation to low-light and nutrient-poor conditions at lower elevations. At higher elevations, plants preferentially allocate resources to increase leaf mass (33.33%) and chlorophyll content (19.02%), improving photosynthetic efficiency, osmotic regulation, and metabolic enzyme activity. This resource allocation promotes nutrient and secondary metabolite accumulation in fruit, enhancing plant stress resistance and fruit quality. This synergistic relationship represents an adaptive adjustment by L. mollis in allocating growth and reproductive resources across different altitude environments. These findings provide a theoretical framework for understanding altitudinal adaptation in L. mollis and offer practical guidance for its introduction, cultivation, and fruit quality improvement in high-elevation regions. Full article

Silicon plays an important role in enhancing plant tolerance to abiotic stress. However, the differential regulatory effects of ionic silicon (Ion-Si) and silicon nanoparticles (SiNPs) on rice seedlings under low temperature (LT) stress have been less studied. This study aimed to investigate the effects of ionic silicon and silicon nanoparticles on rice growth, photosynthetic performance, carbon metabolism, antioxidant defense, and yield formation under low-temperature stress. The results indicated that low-temperature stress significantly inhibited the growth of rice seedlings. Exogenous application of Ion-Si and SiNPs effectively alleviated LT-induced growth inhibition and promoted the recovery of rice. SiNPs demonstrated a stronger effect than Ion-Si in maintaining seedling growth, particularly in enhancing plant height, root length, leaf area, dry weight, and root activity. Low-temperature stress significantly reduced chlorophyll content and photosynthetic capacity, including net photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO₂ concentration, and Rubisco activity. However, under LT stress, both Ion-Si and SiNPs increased chlorophyll content, improved photosynthesis, and enhanced Rubisco activity, with SiNPs showing greater improvement in photosynthetic performance compared to Ion-Si. Additionally, silicon application regulated carbohydrate metabolism by increasing soluble sugar content and enhancing the activities of sucrose phosphate synthase and sucrose synthase, thereby promoting osmotic regulation and energy supply. SiNPs had a stronger effect on carbohydrate metabolism and photosynthate transport than Ion-Si. Furthermore, LT stress increased oxidative damage, manifested as elevated levels of H₂O₂ and malondialdehyde. Exogenous Ion-Si and SiNPs reduced ROS accumulation and lipid peroxidation by increasing the activities of antioxidant enzymes, including superoxide dismutase, peroxidase, and catalase. Compared with Ion-Si, SiNPs showed a stronger ability to enhance antioxidant defense and alleviate oxidative damage. Application of silicon mitigated yield loss under low temperature stress, and SiNPs was more effective than Ion-Si in maintaining rice yield, mainly by increasing the number of effective panicles, grains per panicle, and seed setting rate. This study revealed the distinct physiological roles of Ion-Si and SiNPs in rice cold tolerance and provided a theoretical foundation for the application of silicon-based fertilizers in rice production under low-temperature conditions. Full article

Drought impairs osmotic adjustment and photosynthetic performance in legumes; however, the role of micronutrients in modulating these responses across genotypes remains unclear. This study investigated the effects of selenium on the osmolytes and photosynthetic efficiency in two vegetable-soybean (Glycine max L. Merrill) cultivars differing in drought responses: UVE14 (drought-tolerant) and UVE17 (drought-susceptible). Plants were grown under well-watered (100% soil water-holding capacity, WHC) and water-limited (30% soil WHC) conditions, with or without soil-applied selenium. Free amino acids, soluble sugars, chlorophyll pigments, vegetation indices, and chlorophyll fluorescence parameters were assessed at the flowering and pod-filling stages. Under drought conditions, selenium enhanced tolerance primarily by modulating free amino acid metabolism at flowering, increasing aspartate, asparagine, glutamine, and glutamate levels, alongside improvements in chlorophyll content, canopy greenness, and PSII photochemical efficiency. These responses indicate a coordinated adjustment between nitrogen metabolism and photosynthetic function. Both cultivars benefited from selenium application, although the responses were more pronounced in the susceptible cultivar (UVE17). Selenium-induced changes in soluble sugar content were greater under well-watered conditions in both cultivars. The limited accumulation of stress-associated osmolytes, such as proline, following selenium soil drench suggests reduced cellular disruption and mitigation of drought-induced stress. These findings highlight selenium as a context-dependent modulator of drought resilience and emphasize cultivar- and developmental stage-specific effects. Full article

Background: Photodynamic therapy (PDT) is a promising minimally invasive approach for melanoma; however, many photosensitizers lose activity in aqueous media due to aggregation-induced quenching effects. Objectives: The aim of this study was to develop and characterize castor oil–based nanoemulsions containing chlorophyll (NFs-Chl) and to evaluate their in vitro photodynamic potential against melanoma cells (B16-F10), as well as their selectivity compared with human keratinocytes (HaCaT). Methods: NFs-Chl were prepared by spontaneous emulsification. Physicochemical characterization was carried out using dynamic light scattering (DLS), UV–Vis spectroscopy, FTIR, and Raman spectroscopy. In vitro assays included MTT for cell viability (IC₅₀ determination), real-time cell proliferation (RealTime-Glo™), and cell migration analysis (scratch assay). All photodynamic treatments were performed under irradiation at 660 nm. Results: NFs-Chl exhibited homogeneous nanometric sizes (≈24–31 nm) and a low polydispersity index (≈0.25–0.40), indicating a narrow size distribution. UV–Vis spectra confirmed the preservation of the characteristic absorption peaks of chlorophyll after encapsulation. In B16-F10 cells, NFs-Chl associated with PDT significantly reduced cell viability and metabolic activity over 48 h. Furthermore, NFs-Chl inhibited the migratory capacity of B16-F10 cancer cells. Cell migration assays revealed a clear inhibition of B16-F10 cell migration following treatment with NFs-Chl + PDT. Conclusions: Encapsulation of chlorophyll into castor oil nanoemulsions protected the photosensitizer, improved its cellular delivery, and enhanced its photodynamic cytotoxic effect against melanoma cells, while relatively preserving normal keratinocytes in vitro. Full article

Young barley, derived from the early vegetative stage of Hordeum vulgare L., constitutes a plant-based functional ingredient whose phytochemical profile differs markedly from that of mature grain. Two principal commercial forms exist—dried grass powder and juice-derived products—differing in matrix composition and bioactive compound concentration. This narrative review critically evaluates the current knowledge on the phytochemical composition, biological activity, and translational relevance of young barley preparations considered as a functional plant food. The phytochemical spectrum is dominated by C-glycosyl flavones, particularly saponarin and lutonarin, alongside phenolic acids, chlorophylls, enzymatic antioxidants, vitamins, and minerals. Experimental evidence implicates the modulation of redox homeostasis, inflammatory signaling, and metabolic regulators as the primary biological mechanisms. In vitro studies additionally demonstrate antiproliferative activity in human cancer cell lines and immunomodulatory properties mediated by polysaccharide-rich fractions, extending the biological profile of young barley beyond classical antioxidant activity. Although preclinical models consistently demonstrate antioxidant and metabolic effects, high experimental doses and limited preparation standardization restrict the direct extrapolation to human supplementation contexts. Available clinical trials suggest modest improvements in selected lipid, glycemic, and oxidative stress markers; yet, most are small in scale and brief in duration. Agronomic variables including fertilization strategy and soil composition represent additional, underappreciated sources of phytochemical variability and safety concern. Overall, the current evidence supports the biological plausibility of young barley as a functional plant food; yet, the clinical data remain preliminary. Future research should prioritize preparation standardization, dose–response characterization, and agronomic transparency to strengthen translational reliability. In conclusion, young barley preparations represent a biologically plausible functional plant food ingredient with preliminary clinical support, pending confirmation from adequately powered, standardised randomised controlled trials. Full article

Purple basil (Ocimum basilicum L.) is a medicinal plant widely recognized for its richness in bioactive compounds; however, its production in semi-arid regions is often constrained by soil and/or irrigation water salinity. Micronutrient fertilization may contribute to plant stress alleviation under salinity, since elements such as Mn, Mo, and Zn are involved in essential processes related to photosynthetic metabolism and physiological adjustment. This study aimed to evaluate the short-term effects of Mn, Mo, Zn, and their combinations on growth, gas exchange, and relative chlorophyll indices of purple basil plants subjected to severe NaCl stress under greenhouse conditions. The experiment was conducted under greenhouse conditions for 30 days in a randomized block design with nine treatments and four replicates: a non-saline control without micronutrients, a saline control without micronutrients, and plants exposed to 100 mM NaCl with substrate application of Mn, Mo, Zn, MoMn, ZnMo, ZnMn, or ZnMoMn. Micronutrient sources were applied to the substrate at 3.5 g kg⁻¹ according to each treatment. Fertilization with Mn, Mo, Zn, and their combinations enhanced plant stress alleviation under salinity compared with the saline control without micronutrients, with positive responses in growth and physiological performance, including increases in chlorophyll indices. The double combinations MoMn, ZnMo, and ZnMn attenuated the effects of NaCl, especially by increasing leaf area. Mn stood out for increasing net photosynthesis and water-use efficiency, whereas Mo and ZnMo were associated with higher relative chlorophyll indices. Although the triple combination ZnMoMn improved some traits compared with the saline control, its lower efficacy relative to selected single or double applications may indicate that the simultaneous supply of the three elements reduced specific synergistic effects, possibly due to nutritional imbalance or antagonistic interactions among micronutrients under severe salinity. Overall, micronutrient fertilization, particularly through specific double combinations, may contribute to short-term mitigation of NaCl-induced stress responses under controlled greenhouse conditions. Full article

Light irradiance and spectral quality are key environmental factors that influence the growth, photosynthetic performance, and metabolic responses of cyanobacteria. In this study, the effects of increasing white and PAR-red light irradiances on Anabaena variabilis were evaluated in repeated-batch cultures, focusing on photosynthetic efficiency, biomass productivity, and the modulation of antioxidant systems, while cultures maintained under constant irradiance were used as control. Results showed that A. variabilis can maintain photosynthetic efficiency, as indicated by F_V/F_M values, within the optimal range for healthy cultures despite variations in light conditions. PAR-red light, in particular, enhanced biomass productivity and induced stronger photoacclimation responses compared to white light. Moreover, analysis of chlorophyll fluorescence (JIP parameters) revealed that photosynthetic machinery adapts to increased irradiance by modulating energy fluxes. Dissipated energy (DI₀/RC) increases by 4.5-fold under increasing PAR-red light with respect to control cultures, which suggests that PAR-red light promotes thermal dissipation of excess absorbed energy at the phycobilisome level, independently of and complementarily to, the increase in light-harvesting antenna pigments (chlorophylls and phycobiliproteins), thereby reducing the net oxidative pressure in the electron transport chain. The increase in photosynthetic pigments reflects an adaptive adjustment to optimize light harvesting under red light, with a phycocyanin content of 123 mg·g⁻¹ biomass, 30% higher than that obtained in control culture. Overall, A. variabilis demonstrated a robust capacity to acclimate increasing light irradiance and varying light quality through coordinated photoacclimation and antioxidant responses, in repeated-batch cultures. These findings highlight its physiological flexibility, which can be properly driven to maximize the production of valuable bioactive compounds, particularly phycobiliproteins such as phycocyanin, with applications in biotechnology. Full article

The rhizosphere microbiome and phytohormone signaling are critical determinants of plant growth and stress resilience. This study evaluated the combined effects of Streptomyces sp. HU2014 and coronatine (COR) on maize (Zea mays L.) seedlings. Four treatments were established: control (CK), COR seed soaking (Cor), HU2014 soil inoculation (S), and combined S + Cor (SCor). Growth parameters, chlorophyll content, and antioxidant/oxidative stress markers were measured, and root and leaf transcriptomes, together with root metabolomes, were compared between SCor and CK, followed by qRT-PCR validation. Compared with CK, SCor treatment significantly increased stem diameter (~60%), plant height (~20%), and relative chlorophyll content (SPAD, ~50%). Soluble sugar levels were elevated by over 40% in both leaves and roots, accompanied by tissue-specific modulation of antioxidant enzymes. Transcriptomic analysis of SCor vs. CK revealed 2459 differentially expressed genes (DEGs) in leaves and 3444 DEGs in roots; leaves exhibited upregulation of photosynthetic pigment metabolism (porphyrin and carotenoid pathways) and volatile defense compounds (alkaloids and monoterpenoids), whereas roots showed enrichment in phenylpropanoid/flavonoid biosynthesis, benzoxazinoid synthesis, and starch/sucrose metabolism. Metabolomics of SCor vs. CK identified 526 differentially accumulated metabolites (DAMs) in roots, with significant enrichment in aminoacyl-tRNA biosynthesis, phenylalanine metabolism, and linoleic acid metabolism. Integrative multi-omics analysis further revealed that the JA precursor 13-epi-12-oxo-phytodienoic acid co-clustered with stress-responsive transcription factors (e.g., DREB1C), while tricarboxylic acid (TCA) intermediates and phenylpropanoid metabolites were linked to energy and lignin biosynthesis genes. qRT-PCR confirmed the expression trends of 14 out of 15 tested genes. Collectively, combined HU2014 and COR application triggers tissue-specific transcriptional and metabolic reprogramming in maize, coupling JA-mediated stress signaling with enhanced carbon metabolism and secondary defense compound synthesis to promote rhizosphere adaptation and seedling vigor. Full article

Sweet sorghum, a high-quality forage and energy crop, is significantly affected by drought, the primary abiotic stress impacting its growth. Melatonin (MT) has emerged as a crucial signaling molecule in plant responses to abiotic stress. This study investigates the role of melatonin in enhancing drought tolerance in sweet sorghum, specifically using the ‘Dali Shi’ variety under polyethylene glycol (PEG)-induced drought conditions. Our findings demonstrate that exogenous melatonin application significantly increased proline content (by 27.76% and 5.95% under mild and moderate drought, respectively) while decreasing malondialdehyde (MDA) levels (by 18.33% and 35.18%, respectively). Melatonin also enhanced the accumulation of photosynthetic pigments, including chlorophyll b and total chlorophyll, and improved photosynthetic fluorescence parameters (Fv/Fm and ETR). Additionally, melatonin treatment improved root vitality, stimulated carbon and nitrogen metabolism, and increased antioxidant enzyme activity. Transcriptomic analysis revealed that differentially expressed genes were enriched in pathways related to carbon fixation, glycolysis/gluconeogenesis, nitrogen metabolism, antioxidant defense, and plant hormone signaling. Notably, melatonin upregulated key genes associated with these pathways and activated bHLH and MYB transcription factors. In conclusion, this study elucidates the mechanisms by which melatonin enhances sweet sorghum’s drought tolerance, highlighting its potential as a practical approach for improving drought resistance in this crop. Full article

Target of rapamycin (TOR) is a conserved protein kinase that integrates nutrient and energy signals to control growth and metabolism, yet its proteome-level impact in microalgae remains poorly understood. Here, we conducted quantitative proteomics analysis of the unicellular red alga Cyanidioschyzon merolae under rapamycin-induced TOR inactivation to characterize global changes in protein abundance. TOR inhibition triggered widespread metabolic remodeling, including coordinated shifts in carbon and nitrogen allocation, and pronounced changes in protein synthesis, photosynthesis, and energy metabolism. Specifically, proteins associated with ribosome biogenesis and ribosomal subunits declined broadly, indicating impaired translation, alongside pronounced reductions in photosynthetic components, including PSI/PSII subunits and chlorophyll biosynthesis enzymes. In contrast, triacylglycerol (TAG) biosynthesis and starch metabolism were enhanced, indicating a shift towards carbon storage. Notably, a diacylglycerol acyltransferase (DGAT; CMQ199C) and a UDP-glucose pyrophosphorylase (UGP; CMS159C) were strongly induced (2.02-fold and 3.48-fold, respectively), identifying them as candidate targets for enhancing TAG and starch accumulation. Proteins associated with nitrogen assimilation were also upregulated, supporting TOR-dependent regulation of nitrogen metabolism at the protein level. Together, these results indicate that TOR orchestrates proteome-level reprogramming in C. merolae, coordinating growth, energy production, and carbon storage across interconnected metabolic pathways. Full article