Search Results (1,101)

Rapid and accurate diagnosis of nitrogen (N) and phosphorus (P) is crucial for Hydrangea macrophylla nursery management. Traditional methods are time-consuming, and existing non-destructive studies rarely target ornamental plants or support joint N-P diagnosis at the early growth stage. A total of 339 RGB images were captured from potted hydrangeas grown under varying N and P levels at the seedling stage, with 65 phenotypic traits (color, texture, and morphology) extracted. Nutritional status (deficient, optimal, and surplus) was categorized with reference to plant nutrition indices. Discriminant models were then developed using four machine learning algorithms: convolutional neural network (CNN), support vector machine (SVM), random forest (RF), and probabilistic neural network (PNN). The model performances were evaluated using overall accuracy, precision, recall, F1-score, and Cohen’s Kappa coefficient (κ). As a result, CNN achieved 82.65% accuracy (κ = 0.7392) for N classification, and SVM reached 83.65% accuracy (κ = 0.7357) for P classification. Color-related traits dominated the top five contributing features, indicating a stronger correlation with N and P status. This work offers a practical solution for real-time, low-cost, and non-destructive nutrient diagnosis, supporting precision fertilization and enhancing environmental sustainability in nursery production. Full article

Water scarcity, intensified by climate change, limits the growth and survival of threatened tree species, such as Paubrasilia echinata (Lam.) Gagnon, H.C.Lima & G.P.Lewis. This study analyzed the effects of water availability in the soil on the morphophysiology and enzymatic activity of P. echinata seedlings under different irrigation intervals. The experiment consisted of five treatments (irrigation intervals: 0, 3, 6, 9, and 12 days) distributed in four randomized blocks, totaling 20 plots of five plants each. Variables analyzed included stem diameter, number of leaves and leaflets, leaf area, shoot and root length, root volume, dry matter mass, Dickson quality index, relative water content, leaf indices of chlorophyll, peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase. Water deficit reduced root dry matter mass by up to 27.78% and chlorophyll b by up to 29.56%, and increased peroxidase by up to 244.44%. Principal component analysis revealed correlated changes among biomass, chlorophyll, and Dickson index, with root volume and enzymatic activities varying oppositely, indicating an integrated regulatory response. P. echinata exhibits phenotypic plasticity under water deficit, reflected in stem diameter, root volume, leaf area, physiological traits, and enzymatic regulation, tolerating an irrigation interval of 12 days. P. echinata has establishment potential in areas subjected to water deficit. Full article

Calcareous soils are typically deficient in essential nutrients such as iron, phosphorus, and potassium, which frequently results in nutrient deficiency in fruit trees. Bacillus licheniformis LCDD6 markedly enhanced Malus hupehensis seedling growth and plant iron nutrition in calcareous soil. This study aimed to elucidate the mechanism underlying these beneficial effects of strain LCDD6 under iron deficiency. Transcriptomic analysis revealed that iron deficiency induced metabolic reprogramming in strain LCDD6, characterized by a significant upregulation of genes involved in the biosynthesis of the siderophore bacillibactin and plant growth hormone indoleacetic acid (IAA). Consistently, metabolomic profiling identified bacillibactin and IAA as the dominant metabolites produced under iron-deficient conditions. A 60-day pot experiment further demonstrated that the cell-free fermentation broth of strain LCDD6 significantly enhanced plant growth and rhizosphere soil enzyme activities. The crude bacillibactin extract derived from the fermentation exerted the strongest effects on plant growth and iron accumulation, whereas IAA preferentially stimulated root development and promoted plant phosphorus accumulation. Additionally, different metabolites exerted distinct and selective effects on the rhizosphere microbial community, with fungi showing stronger and more metabolite-specific responses than bacteria. The crude bacillibactin extract enriched fungal taxa, particularly Coprinellus, which showed strong positive correlations with plant growth traits and iron accumulation, while Stachybotrys, enriched under IAA treatment, was positively correlated with plant phosphorus content. Overall, strain LCDD6 promotes plant growth under iron-deficient conditions through the coordinated action of multiple metabolites, with bacillibactin as the primary contributor and IAA providing complementary effects. These findings offer mechanistic insight and a scientific basis for developing Bacillus-based biofertilizers to improve nutrient acquisition in calcareous soils. Full article

Among the options to improve the establishment of jalapeno pepper (Capsicum annuum L.), physical biostimulants such as far-infrared bioceramics (FIR) and static magnetic fields (MF) have emerged as non-chemical alternatives. This study evaluated, under in vitro conditions, the individual and combined effects of FIR and positive or negative MF on seed germination dynamics, early seedling morphology, water status, and photosynthetic pigments. A completely randomized design with eight treatments was implemented, including FIR applied continuously throughout the entire experimental period, positive or negative MF applied for 24 h (MF⁺₂₄, MF⁻₂₄), and FIR + MF combinations under continuous or 24 h exposure regimes (n = 7). Germination percentage, mean germination time (MGT), mean germination rate (MGR), germination index (GI), morphological variables, water content (WC), and photosynthetic pigments were measured; ANOVA/alternative tests (a = 0.05), Principal Components Analysis (PCA) and exploratory Spearman’s correlations were used to assess relationships among the evaluated variables. Germination percentage did not change (97.64%), but kinetics did: FIR + MF⁻₂₄ reduced MGT to 4.32 d, FIR increased MGR to 5.83 seeds day⁻¹ (+11.69%), and FIR₂₄ + MF⁺₂₄ showed the highest GI (4.57). For morphological, MF⁺₂₄ increased hypocotyl length (+16.29%), FIR increased collar diameter (+27.27%), and FIR + MF⁻₂₄ increased cotyledon area (25%), and FIR increased chlorophyll a (+139%), chlorophyll b (+141%), and carotenoids (+114%). PCA explained 66.9% of the variance, grouping FIR with growth variables and FIR + MF combinations with WC and pigments. Inferences are limited to one cultivar and controlled in vitro conditions. This study provides novel quantitative evidence that continuous and short-term applications of FIR and MF modulate germination dynamics and early physiological traits without altering final germination, related to structure and pigments, without changing final germination percentage. Full article

This study investigated the effects of environmentally friendly soil amendments—processed red clay (PRC) and rice husk (RH)—on early establishment, growth characteristics, phytochemical accumulation, and soil chemical properties in wild-simulated ginseng (WSG; Panax ginseng C.A. Meyer) cultivated under forest conditions. PRC was produced through alkali-assisted thermal processing to improve material homogeneity and enhance plant-available mineral components, particularly silicon. We hypothesized that the combined application of PRC and RH would improve soil chemical conditions and thereby support WSG growth and phytochemical accumulation under low-input cultivation systems. Four treatments were evaluated in a randomized complete block design with four replicates: non-treated control (NMNF), PRC alone (NMPRC), RH alone (RHNF), and combined PRC and RH (RHPRC). Growth responses were assessed in one-year-old and seven-year-old WSG, including germination rate, seedling vigor index, growth traits, photosynthetic pigment composition, total polyphenol content, ginsenoside profiles, and soil chemical properties. The RHPRC treatment significantly increased germination rate and seedling vigor compared to the non-treated control and showed consistently greater biomass accumulation across cultivation stages. RH application was primarily associated with improved early establishment and increased total polyphenol content, particularly during the early growth stage, whereas PRC application was associated with enhanced root development and age-dependent increases in selected ginsenosides. Soil analyses indicated that PRC application increased available phosphorus and exchangeable cation contents, with the most stable improvements observed under combined PRC and RH treatment. Overall, the results indicate that integrated mineral–organic soil management using PRC and RH can improve soil chemical propertise and support long-term growth and phytochemical accumulation in WSG cultivated under forest conditions. This approach offers a practical, low-input strategy for enhancing the sustainability of WSG cultivation while reducing reliance on synthetic fertilizers. Full article

Brown spot, caused by the seedborne fungus Bipolaris oryzae, remains a major constraint in rice production. Here, we used in vitro and in vivo assays to evaluate the biocontrol potential of three Bacillus strains (Ba. cereus OQ725688.1, Ba. velezensis OP938696.1, and Ba. subtilis OP937353.1) against Bi. oryzae in two rice cultivars (“Rubelita” and “Predileta”). Ba. cereus showed the highest in vitro mycelial inhibition (≈95%), whereas Ba. velezensis was the most effective under greenhouse conditions, reducing disease severity by up to 60% and increasing seedling vigor by 51% compared with infected controls. “Predileta” showed the strongest response to bacterial treatment, maintaining severity scores below 2 even under high inoculum pressure. Functional assays confirmed that all strains displayed amylolytic, catalase, and phosphate-solubilizing activities, with Ba. velezensis uniquely expressing strong cellulase and protease activities. Genome analysis of Ba. velezensis OP938696.1 revealed multiple biosynthetic gene clusters for antifungal polyketides and lipopeptides. These integrated biochemical and genomic traits demonstrate the novelty and potential of this Neotropical strain as a multifunctional agent capable of suppressing Bi. oryzae while enhancing rice seedling performance. Incorporating such a native strain into seed and soil management offers a sustainable strategy for rice protection in Neotropical systems. Full article

Drought severely limits plant productivity, and understanding its regulatory mechanisms remains essential. Here, we characterize Lipid Transport Superfamily-Polyketide cyclase/dehydrase (LTS-PYL), a PYR/PYL/RCAR-domain gene, using Arabidopsis overexpression and CRISPR-Cas9 genome-edited lines to elucidate its role in drought adaptation. LTS-PYL overexpression enhanced early seedling growth, increasing root length (RL) by 40% and 31%, whereas genome-edited lines exhibited severe defects, including 42%, 28% reductions in fresh weight and 63%, 50% decreases in root length relative to WT-T. Under drought stress, overexpression lines displayed strong growth and reproductive resilience, with shoot length (SL) increased by up to 80%, silique length (Sil L) by 61%, and seed number doubled compared with WT-T. In contrast, genome-edited lines showed marked reductions in these traits, confirming their drought sensitivity. LTS-PYL overexpression strongly suppressed oxidative stress, reducing H₂O₂ by 74% and 68% and O₂⁻· by 39% and 38%, while increasing relative water content (RWC) by 42% and 39%. Genome-edited lines exhibited elevated (H₂O₂, O₂⁻·) and up to 33% lower RWC. Antioxidant capacity was also strengthened in overexpression plants, with catalase (CAT) and peroxidase (POD) activities increasing by 138%, 168% and 62%, 148%, and malondialdehyde (MDA) and electrolyte leakage (EL) reduced by 23%, 37%, relative to WT-T. Conversely, genome-edited lines showed weakened antioxidant defenses and higher membrane damage. Transcriptionally, overexpression activated drought-responsive genes, elevating LTS-PYL (604%, 472%), DREB2A (227%, 200%), and ABA levels (48%, 34%), whereas genome-edited lines showed strongly reduced expression and ABA decreases of 66%, 62%. Additionally, LTS-PYL enhanced osmotic adjustment, increasing proline (58%, 53%), sugars (37%, 46%), and sucrose (111%, 100%), while limiting chlorophyll (Chl) loss to 9%, 20%. Genome-edited lines exhibited reduced osmolytes and severe chlorophyll decline. Overall, LTS-PYL acts as a strong positive regulator of drought tolerance, integrating ABA signaling, osmotic adjustment, ROS detoxification, and transcriptional activation. Full article

Water and nitrogen supply are key factors limiting the establishment of alpine plant seedlings and the efficiency of ecological restoration on the Tibetan Plateau. As an endemic shrub to Tibet, the morphological and physiological response mechanisms of Piptanthus nepalensis (Hook.) D. Don to coupled water and nitrogen stress remain poorly understood. This study employed a pot experiment with a completely randomized two-factor design, incorporating five water gradients (0–100% field capacity, FC) and five nitrogen levels (0–4 g·plant⁻¹ urea). The aim was to elucidate the regulatory mechanisms of water/nitrogen coupling on Piptanthus nepalensis growth, physiology, and morphogenesis. The results indicated the following: (1) A significant water/nitrogen coupling effect was observed, with optimal water/nitrogen combinations producing pronounced synergistic effects. Principal component analysis (PCA) revealed that the first two axes cumulatively explained 99.32% of the morphological variation. The W3N3 treatment (40–60% FC water + 2 g·plant⁻¹ nitrogen) exhibited optimal growth traits and maximum leaf elongation, establishing the optimal water and fertilizer management threshold for this species. (2) Confronted with two starkly contrasting stresses—drought (W4, W5) and waterlogging (W1)—plants adopted convergent “conservative” morphological adaptation strategies (significantly reduced leaf length and width) to lower metabolic expenditure. (3) Photosynthetic physiological analysis revealed that under extreme water deficiency (W5) or waterlogging (W1) stress, intercellular CO₂ concentration (Ci) paradoxically increased, indicating a shift in photosynthetic suppression mechanisms from stomatal limitation to non-stomatal limitation (metabolic injury). (4) The Mantel Test confirmed that photosynthetic physiological traits significantly drove morphological trait variation (p < 0.001), establishing a close feedback loop between “physiological function and morphological structure”. Conclusions: Moderate water deficit (40–60% FC) combined with moderate nitrogen fertilization (2 g·plant⁻¹) effectively alleviates non-stomatal limitation and releases morphological constraints, thereby promoting rapid growth in Piptanthus nepalensis. This study reveals the phenotypic plasticity and convergent adaptation mechanisms of Piptanthus nepalensis under water/nitrogen co-stress, providing precise water and fertilizer management guidelines for vegetation restoration in degraded ecosystems of Tibet. Full article

Increasingly frequent extreme droughts threaten forest vegetation and highlight the need to identify drought-tolerant germplasm. To support conservation and cultivation of Illicium lanceolatum, we investigated ecotypic differences in photosynthetic responses to short-term drought and rewatering under varying light intensity. One-year-old seedlings from four I. lanceolatum ecotypes originating from the Zhejiang (Lin’an, LA; Kaihua, KH), Jiangxi (Wu’ning, WN), and Fujian (Nan’ping, NP) provinces in China were subjected to drought stress by withholding irrigation and subsequent rewatering. Photosynthesis–light response curves were measured before drought; 2, 4, and 7 days after the last watering; and following rewatering. Short-term drought significantly affected photosynthetic traits in an ecotype-dependent manner. Maximum net photosynthetic rate, light saturation point, light compensation point, and apparent quantum yield increased during drought, indicating enhanced utilization of both high and low light. After rewatering, stomatal conductance increased significantly in the WN and KH ecotypes but declined in the NP ecotype when compared with those under the initial water supply. Instantaneous water use efficiency (A/E) recovered rapidly in all ecotypes and exceeded pre-drought levels. Under light intensity above 1500 µmol·m⁻²·s⁻¹, stomatal conductance exhibited a significant nonlinear relationship with water use efficiency. Overall, these physiological responses indicate that I. lanceolatum is moderately drought-tolerant and exhibits mild sensitivity to soil water variation. The WN and KH ecotypes showed superior improvement in water use efficiency under drought and high light, suggesting their potential for breeding drought-resistant cultivars and for afforestation in drought-prone environments. Full article

Drought poses a major challenge for global agriculture, demanding strategies that improve crop resilience while safeguarding water and nutrient resources. Plant growth-promoting rhizobacteria (PGPR)-based biostimulants offer a sustainable approach to enhance resource-use efficiency under water-limited conditions. This study evaluated two commercial PGPR biostimulants applied to maize (Zea mays L.) and tomato (Solanum lycopersicum L.) seedlings grown under well-watered (80% field capacity) and water-stressed (40% field capacity) conditions. Both products improved plant growth and physiological performance, although responses were crop-specific. Inoculated tomato seedlings accumulated up to 35% more shoot biomass under optimal watering (1.6 g in non-inoculated seedlings compared with 2.5 g in inoculated seedlings), whereas maize maintained biomass production under drought, consistent with its higher intrinsic water-use efficiency, showing increases of approximately 50% (well-watered: 0.5 g versus 0.8 g; water-stressed: 0.3 g versus 0.7 g in non-inoculated and inoculated seedlings, respectively). Biostimulant application enhanced the acquisition and internal utilization of essential mineral resources, increasing leaf concentrations of (i) the macronutrients P (up to 300%), K (up to 70%), Mg (up to 220%), and Ca (up to 85%), and (ii) the micronutrients B (up to 400%), Fe (up to 260%), Mn (up to 240%), and Zn (up to 180%). Maximum nutrient increases were consistently observed in water-stressed maize seedlings inoculated with biostimulant 2. Antioxidant activities, particularly ascorbate peroxidase and catalase, increased by 20–40%, indicating more effective mitigation of oxidative stress. Principal component analysis revealed coordinated adjustments among growth, nutrient-use efficiency, and physiological traits in inoculated plants. Overall, PGPR-based biostimulants improved early drought tolerance and resource-use efficiency, supporting their potential as sustainable tools for climate-resilient agriculture. Field-scale studies remain necessary to confirm long-term agronomic benefits. Full article

Climate change is altering temperature and precipitation regimes in Argentina, with potential consequences for regeneration and persistence of forest tree species, emphasizing the importance of ex situ seed conservation. We evaluated interannual variation in seed traits, desiccation tolerance, storage behavior, and longevity of Cedrela balansae C. DC. and C. fissilis Vell. (Meliaceae), two endangered native species of subtropical rainforests in Argentina. Both species produced desiccation-tolerant seeds, independently of collection year, seed traits, or climatic conditions. Depending on the species, seed traits and longevity varied across years and showed strong relationships with temperature and precipitation, particularly during seed development. Cedrela balansae seeds are medium-lived seeds and have high longevity under standard seed banking conditions, suggesting strong potential for long-term ex situ conservation. Cedrela fissilis seeds are short-lived seeds and have high sensitivity to the storage environment. Correlations among climatic variables and seed traits and longevity parameters suggest that future warming and drying environments may shorten the window for germination and seedling establishment, with species-specific responses depending on climatic conditions during seed development. These results highlight the importance of climate effects in determining seed traits and seed longevity and emphasize the role of seed banking as a critical conservation strategy under climate change. Full article

Although cytoplasmic male sterility (CMS) is well established in eggplant, CMS-based interspecific hybrids with allied species have not yet been reported or studied. In this study, five previously developed CMS-based interspecific F₁ hybrids between eggplant and Solanum aethiopicum Group Aculeatum (=S. integrifolium) and Group Gilo (=S. gilo), together with their parental lines, were morphologically evaluated for 67 seedling, vegetative, floral, and fruit traits, and their heterosis for vegetative growth was studied. Male fertility was assessed based on anther morphology and pollen viability, while female fertility was evaluated through backcrosses to both parents. The hybrids exhibited predominantly intermediate phenotypes and clustered distinctly from parental lines as confirmed by principal component analysis. Remarkable heterosis was observed for most growth-related traits, indicating favorable nuclear–cytoplasmic interactions despite the use of CMS eggplant lines as maternal parents. All hybrids showed complete male sterility, characterized by non-viable pollen and pronounced anther homeotic alterations, the latter indicating CMS-related effects on male fertility. Female fertility was severely reduced, likely due to meiotic irregularities, as evidenced by the failure of most attempted backcrosses. However, successful recovery of BC₁ progeny after backcrossing one CMS-based F₁ hybrid to S. gilo demonstrates partial reproductive compatibility and provides a genetic bridge for CMS introgression into S. gilo. These results indicate that CMS systems are suitable for eggplant interspecific crosses aimed at vigorous rootstock production and CMS cytoplasm introgression into allied germplasm. Full article

Low salinity tolerance during germination and early seedling establishment limits large-scale cultivation of halophytes for forage, food, restoration, and conservation purposes. This study evaluates the potential of redox priming to enhance salt tolerance in the perennial C₄ halophyte grass Urochondra setulosa, which could be used as a revegetation and phytoremediation crop for coastal saline lands. Fresh seeds were found to be non-dormant with ~90% mean final germination (MFG) in distilled water. Redox priming, including hydrogen peroxide (H₂O₂), melatonin (MT), sodium nitroprusside (SNP; a nitric oxide donor), and ascorbic acid (AsA), significantly accelerated the germination rate index (GRI) and reduced mean germination time (MGT) without altering MFG under non-saline conditions. Salinity severely suppressed germination, as unprimed seeds reached only ~1% MFG with ~99% germination reduction (GR) and near-zero germination stress tolerance index (GSTI) at 200 mM NaCl. All priming treatments significantly improved MFG, GRI, and GSTI and decreased GR, with H₂O₂ priming showing the highest amelioration. Ungerminated seeds from all treatments recovered ~90% germination capacity in water, indicating enforced dormancy owing to osmotic constraints. Salinity did not impair growth in unprimed seedlings. However, MT priming uniquely enhanced total length, leaf area, and seedling vigor index (SVI) at 200 mM NaCl, while MT and SNP priming resulted in the highest chlorophyll and carotenoid contents. Multivariate analyses confirmed MT’s consistent superiority across traits under stress. Thus, H₂O₂ priming optimizes germination, while MT priming improves seedling vigor and offers a practical, targeted strategy to improve early-stage salinity tolerance in U. setulosa for coastal revegetation and sustainable saline agriculture. Full article

Invasive plant species persist under environmental conditions due to phenotypic plasticity, which allows them to cope with conditions such as herbivory, competition, and resource availability. However, plant responses to individual and combined stressors are variable. In addition, fluctuating asymmetry (FA) has been proposed as an indicator of plant stress, although its reliability remains debated, and few studies have evaluated its responses under interacting stressors. We evaluated, in two greenhouse experiments, the isolated and combined effects of herbivory and shading; and belowground intraspecific competition and fertilization on performance, trait plasticity, and leaf FA in seedlings of the invasive plant Tithonia diversifolia. Shading reduced shoot biomass, but promoted plastic adjustments in architectural, photosynthetic, and leaf structural traits that enhance light capture, and also increased FA. Herbivory interaction with shade induced high leaf mass per area of plants. In contrast, high herbivory and intraspecific competition consistently reduced plant performance across multiple traits. Fertilization enhanced overall performance and mitigated the negative effects of herbivory and competition. Overall, our results emphasize the need to consider interacting environmental factors when assessing invasive plant performance and plasticity. Furthermore, FA showed inconsistent responses across treatments, suggesting its limited reliability as a biomarker of isolated and combined environmental stress. Full article

Black point (BP) and Fusarium-damaged kernels are common disorders affecting wheat grains worldwide. While the negative impact of Fusarium head blight (FHB) on yield and grain quality is well established, the biological significance of BP remains debated. This study evaluated the effects of BP on yield-related traits and seedling performance of winter wheat and compared them with the effects of FHB. Four winter wheat cultivars (Mercedes, Adina, Steffi, and LG Mocca) were examined under field and laboratory conditions. Fusarium infection was induced by artificial inoculation with Fusarium culmorum, whereas BP was assessed under natural field conditions using non-inoculated control plants. Fusarium infection significantly reduced thousand-grain weight (up to 46%) and grain number per ear (up to 35%). In contrast, BP was not associated with yield reduction. Grain with BP symptoms showed a 10–30% higher thousand-grain weight compared with BP-free grain. Seedlings originating from BP-affected seeds exhibited equal or improved biometric traits and a higher vigor index. Phytopathological analysis showed that Alternaria spp. dominated the endophytic mycoflora of both BP-affected and BP-free seeds. These results indicate that, under the conditions of this study, BP did not negatively affect wheat yield or seedling vigor and differed fundamentally from the damaging effects of FHB, highlighting the importance of distinguishing BP from Fusarium-related damage in wheat production. Full article