Search Results (10,852)

Phosphorus deficiency in the environment induces phosphate (Pi) starvation responses of plants, in which the phosphate transporter is one of the most critical functional genes in this response mechanism. As a prevalent green manure crop in China, Vicia villosa plays a critical role in sustainable agricultural systems, and the expression of its phosphate transporter gene (VvPHT1) is modulated by soil phosphorus availability, highlighting its key adaptive function in nutrient acquisition and utilization under low-Pi conditions. Functional studies of this gene and its promoter contribute to exploring the molecular mechanisms of the tolerance of green manure crops to low phosphorus stress and to improving phosphorus-efficient V. villosa varieties. In this study, analysis of the VvPHT1 promoter sequence revealed a 1524 bp region containing multiple root-specific cis-regulatory elements, including five NODCON2GM, one NODCON1GM, six OSE2ROOTNODULE, one OSE1ROOTNODULE, and fifteen ROOTMOTIFTAPOX1 motifs. Histochemical GUS staining of transgenic Arabidopsis (Arabidopsis thaliana (L.) Heynh.) showed that the VvPHT1 promoter directed root-specific expression of the GUS reporter gene. A fusion expression vector pCAMBIA1300-VvPHT1--GFP was constructed and transformed into tobacco (Nicotiana tabacum L.) cells for subcellular localization analysis, indicating that the protein encoded by VvPHT1 was localized to the plasma membrane. To quantify its expression, VvPHT1 transcript levels in VvPHT1-overexpressing Arabidopsis (OEPHT1) lines were analyzed by quantitative real-time PCR (qRT-PCR) under different phosphorus supply conditions. The results demonstrated that under low-Pi conditions, the expression of VvPHT1 was significantly upregulated in the OEPHT1 lines compared to those of normal-Pi conditions. Furthermore, under low-Pi treatment, the OEPHT1 lines showed significantly increased fresh weight, primary root length, phosphorus content, and chlorophyll content compared to the wild-type Arabidopsis (WT), while no such differences were observed under normal-Pi conditions. In conclusion, the VvPHT1 promoter exhibits root-specific activity, and the VvPHT1 gene encodes a plasma-membrane-localized phosphate transporter that is strongly induced by phosphorus deficiency. Its overexpression enhances phosphorus uptake and plant growth under low-Pi conditions, suggesting that VvPHT1 likely functions as a high-affinity phosphate transporter involved in the adaptation to phosphorus starvation. Full article

The rapid expansion of seaweed aquaculture has profound impacts on coastal ecosystems, yet the lack of long-term, high-precision spatiotemporal monitoring methods has constrained systematic understanding of aquaculture dynamics and their environmental effects. This study integrated Landsat (1984–2025) and Sentinel-2 (2015–2025) imagery with an attention-enhanced U-Net deep learning model to achieve 41 years of continuous monitoring of seaweed aquaculture in the Dongtou Archipelago, Zhejiang Province, China. The model achieved high extraction accuracy for both Landsat and Sentinel-2 aquaculture areas (F1 scores of 0.972 and 0.979, respectively). On this basis, the cultivation zones were further classified into Porphyra sp. and Sargassum fusiforme cultivation areas by incorporating local aquaculture planning and field survey data. Results showed that the aquaculture area underwent three developmental stages: slow initiation (1984–2000, <3 km²), rapid expansion (2001–2015, 3–8 km²), and high-level fluctuation (post-2015, typically 8–20 km²), reaching a peak of ~30 km² during 2018–2019. Long-term retrieval of water quality parameters revealed that the decline in total suspended matter (from ~80 to 60 mg/L) and chlorophyll (from ~3 to 2 μg/L) within aquaculture zones was significantly greater than that in non-aquaculture areas, providing direct observational evidence for local water quality improvement by appropriately scaled aquaculture. Meanwhile, sea surface temperature showed a sustained increasing trend, with extremely high-temperature days (≥25 °C) exhibiting strong interannual variability, posing potential thermal stress risks to cold-preferring seaweed species. The NDVI (Normalized Difference Vegetation Index) and FAI (Floating Algae Index) indices effectively captured aquaculture phenology (seeding, growth, maturation, harvest), with their interannual peaks exhibiting an inverted U-shaped correlation with corresponding yields (R = 0.82 and 0.79, respectively, based on quadratic regression fitting), preliminarily demonstrating the potential of remote sensing in indicating density-dependent effects. This study systematically demonstrates the comprehensive capability of multi-source satellite remote sensing in long-term dynamic monitoring, environmental effect assessment, and yield relationship analysis of seaweed aquaculture, providing key technical support and scientific basis for aquaculture carrying capacity management and ecological risk prevention in island waters. Full article

Wheat productivity and grain quality are strongly influenced by nutrient management and soil moisture availability. Nitrogen (N) and potassium (K) regulate biomass production, physiological stability and grain protein development. However, their efficiency varies under water-limited conditions. This study aimed to evaluate how soil moisture modulates nitrogen–potassium efficiency, nutrient partitioning, physiological responses and grain quality development in wheat. The current experiment was planned to assess the impact of varying but combined levels of N and K fertilizers on wheat crop growth and yield components as well as nutrient uptake and grain quality under different irrigation levels (i.e., normal irrigation Field Capacity (FC) 100%, partial water deficit FC75%, moderate water deficit FC50%, severe water deficit FC25%). The results of the study showed that increasing N-K supply enhanced biomass, chlorophyll contents, nutrient accumulation and grain quality under full irrigation, with N2K2 showing the highest growth, yield and quality traits. Under moderate deficit, N2K1 maintained a relatively stable yield and physiological performance, whereas severe moisture limitation markedly reduced nutrient uptake, grain development and fertilizer efficiency despite a higher NK application. Progressive reductions in irrigation also altered nutrient distribution among leaves, straw and grain, indicating moisture-regulated remobilization during grain filling. Maximum increments in values for plant height (27%), total biomass (108%), grain yield (183%), grain NPK content (38%, 6.3%, 26%), grain protein (38%) and wet gluten (38%) were noted in the N2K2 treatment at FC100%, but these parameters showed up to 80% reduction under the same treatment of N-K at FC25%. It is concluded that wheat response to N–K fertilization was moisture dependent and fertilizer rate alone did not ensure productivity under severe water deficit. Therefore, integrating nutrient supply with irrigation management is essential to sustain productivity and grain quality. Full article

This study evaluates the impact of recirculating aquaponic cultivation on the biochemical, mineral, and antioxidant profiles of Swiss chard (Beta vulgaris var. cicla) integrated with Nile tilapia (Oreochromis niloticus), which serves as a source of nutrients through metabolic waste transformation within the system. Water quality parameters and microbiological testing confirmed efficient nitrification and system safety, with no Escherichia coli detected. Results showed that aquaponic cultivation yields a high nutritional value of Swiss chard, yielding high crude protein (31.4% DW) and mineral-rich biomass (ash 22.8% DW). Substantial concentrations of essential elements were recorded, including Ca, Mg, Fe (253.7 mg/kg DW), Zn, and Cu, suggesting high ionic bioavailability in the recirculating system. Physiological stability was reflected by a chlorophyll a content of 4.74 mg/g DW. Furthermore, the plants exhibited a robust phytochemical profile, with total phenolics (4.13 mg GAE/g DW) and flavonoids (5.18 mg QE/g DW) driving strong antioxidant activity (93.1% ABTS inhibition). These findings demonstrate that integrated aquaponic systems function as effective nutrient bioreactors, supporting high plant functional quality while supporting sustainable food production. The results validate aquaponics as a viable, climate-smart strategy for high-quality leafy vegetable cultivation within a circular bioeconomy framework. Full article

The increasing prevalence of antimicrobial resistance, together with recurring infectious disease outbreaks, has intensified the need for alternative strategies to control microbial infections beyond conventional antibiotic therapies. Antimicrobial photodynamic therapy has emerged as a promising non-antibiotic approach in which light-activated photosensitising compounds generate reactive oxygen species that induce oxidative damage to microbial cells. Plant-derived photosensitisers have attracted increasing attention due to their structural diversity, biocompatibility, natural abundance, and potential for sustainability. Natural compounds such as curcumin, hypericin, chlorophyll derivatives, flavonoids, anthraquinones, and riboflavin exhibit favourable photochemical properties that enable efficient production of reactive oxygen species upon irradiation with visible light. Through radical- and singlet-oxygen-mediated photochemical pathways, these molecules exhibit broad-spectrum antimicrobial activity against bacteria, fungi, viruses, and biofilm-associated microorganisms. This review examines the photophysical properties and mechanisms of reactive oxygen species generation associated with plant-derived photosensitisers, together with key factors influencing their antimicrobial performance. Recent advances in nanocarrier-based delivery systems, dual-wavelength activation strategies, and synergistic combination therapies are also discussed for their potential to improve photostability, enhance reactive oxygen species generation, and increase microbial inactivation efficiency. Finally, current progress, challenges, and future research directions for advancing plant-derived photosensitisers in antimicrobial photodynamic therapy are discussed. Full article

Global freshwater resources face severe water quality degradation, with chlorophyll-a (Chl-a) concentration serving as a critical eutrophication indicator. While deep learning methods enable accurate Chl-a retrieval from remote sensing reflectance (Rrs) spectra, the scarcity of paired Rrs-Chl-a samples limits model generalization and causes overfitting, particularly in optically complex inland waters. To address this data bottleneck, we propose a physics-constrained latent diffusion model for synthesizing high-fidelity paired Rrs-Chl-a data to augment limited training sets for deep learning-based water quality retrieval. Our framework integrates three key innovations: (1) a lightweight variational autoencoder achieving 8.6:1 latent space compression, reducing computational overhead while preserving spectral features; (2) band-selective attention mechanisms targeting chlorophyll-sensitive wavelengths (440, 550, 680, and 700–750 nm) based on bio-optical principles; and (3) physics-guided conditional encoding that captures concentration-dependent spectral responses across oligotrophic to eutrophic regimes. Evaluated on the GLORIA dataset, our model demonstrates superior performance in spectral similarity (0.535), sample diversity (0.072), and distribution matching (Fréchet distance 0.0008) compared to conventional generative models. When applied to data augmentation, synthetic spectra improved downstream Chl-a retrieval from R²= 0.75 to 0.91, reducing RMSE by 39%. This physics-informed generative approach addresses data scarcity in aquatic remote sensing research, supporting global needs for enhanced understanding of inland and coastal water quality dynamics in data-limited regions. Full article

Shade management, which is widely adopted in cultivation and understory regeneration, alters plant light environments, thereby degrading the trait inversion performance and posing a key challenge in plant phenotyping. To address this issue, this study reframed chlorophyll retrieval of Hopea hainanensis under shade management as an illumination-regime-dependent conditional domain shift problem, and developed a condition-aware domain adaptation framework (CAI-DAI) tailored to this setting. The results showed that chlorophyll content increased with shading intensity, accompanied by clear differences in canopy spectral distributions among shading levels, supporting the presence of condition-dependent variation under shade management. Model comparisons showed that CA-IE and CAI-DAI, which integrate conditional encoding and conditional alignment, performed better than the comparative models across fine-tuning ratios from 30% to 70%. Among them, CAI-DAI achieved the best and most stable performance, with test MAE ranging from 4.355 to 4.774 μg·cm⁻² and nRMSE ranging from 16.4% to 18.2%, and R² ranging from 0.456 to 0.585. Further evaluation at individual shading levels (S1–S4) showed that CAI-DAI produced narrower error ranges than CA-IE. It also showed smaller error fluctuations under most fine-tuning ratios. These results demonstrate that the proposed framework effectively improves robustness under heterogeneous shading conditions and limited labeled samples, providing methodological support for chlorophyll monitoring and decision-making related to shade management. Full article

Asparagus (Asparagus officinalis L.) represents a high-value horticultural crop in Thailand with significant export potential; however, optimizing productivity in tropical environments requires a precise understanding of how cultivation practices and harvest seasons influence marketability. Here, a split-plot experiment arranged in a completely randomized design with three replications was conducted to examine how different crop methods and harvest seasons affect asparagus yield and quality in Lopburi Province, Thailand. The main plots were categorized by harvest season—summer, rainy, and winter—while the subplots included three crop methods: conventional, GAP, and organic. Summer produced the highest yield and asparagus with the greatest levels of total chlorophyll, phenolics, and DPPH radical scavenging activity compared to other seasons. Although the conventional methods yielded the most spears per plant, these spears contained higher levels of contaminants, including cadmium, lead, and nitrate. In contrast, spears from GAP and organic methods had higher phosphorus levels. However, no pesticide residues were found in any spear samples. Economically, the organic method had the shortest payback period, owing to lower production costs; despite a lower annual yield, stable market prices kept it profitable. In addition, organic soils had the highest levels of organic matter, nitrogen, and phosphorus. Overall, while conventional methods enhance the yield and certain qualities, organic farming, particularly when harvested in summer, yields the highest economic returns and the most sustainable system among those tested. Full article

In this study, we aimed to isolate indigenous plant-growth-promoting rhizobacteria (PGPR) with high indole-3-acetic acid (IAA)-producing capacity from alfalfa rhizospheres in arid regions of Northwest China and systematically evaluate their bioacceleration effects on alfalfa growth. Fifteen bacterial strains were isolated from rhizosphere soils collected in Ningxia and Inner Mongolia. Among them, four high-IAA-producing strains were selected and identified as Brevundimonas sp. B3, Pantoea sp. P10, and Microbacterium sp. M1 and M7 based on 16S rDNA sequencing. Pot experiments showed strain-specific growth-promoting effects: P10 significantly increased plant biomass (increasing fresh weight by 10.04% and dry weight by 11.76%, with p < 0.05), while M7 notably enhanced plant height (by 16.48%, with p < 0.05) and branching. Physiological and cytological analyses revealed that the tested strains improved chlorophyll content (30–45% above the control), reduced malondialdehyde (MDA) levels (20–40% below the control), and differentially regulated root-tip cell elongation. Principal component analysis further supported the comprehensive promotive effects of these strains, with P10 exhibiting the highest overall performance (PC1–PC4 cumulative variance: 83.1%). Within the limitations of controlled pot experiments, these findings highlight the potential of native PGPR strains, particularly P10 and M7, as promising candidates for developing region-specific microbial inoculants with which to enhance alfalfa productivity in arid and semi-arid environments. Full article

The effects of environmental factors on zooplankton within the marginal ice zone (MIZ) of the Barents Sea remain poorly understood. To address this knowledge gap, we investigated mesozooplankton communities across the central, northern, and northeastern regions in April 2016. Abundance and biomass ranged from 90 to 997 individuals m⁻³ and from 1.1 to 48.6 mg dry mass m⁻³ (0.3 to 13.6 g dry mass m⁻²), respectively. Oithona similis was the most abundant taxon, while calanoid copepods, including Calanus spp., Metridia longa, and Pseudocalanus spp., dominated total biomass. The spatial distribution of mesozooplankton communities was closely linked to the physical properties of water masses. Cluster analysis identified two distinct assemblages associated with Polar Front Water and Arctic Water. Redundancy analysis and generalized linear models identified temperature, mean salinity, mean chlorophyll a concentration, and sea ice concentration as significant predictors of abundance and biomass. The dominance of older life stages within major copepod taxa indicated a winter status for the mesozooplankton community. Regional and temporal comparisons of mesozooplankton biomass with prior May–June data from central and northwestern areas highlighted higher productivity in the northern and northeastern MIZ. This increase is potentially related to the warming trends observed in the Arctic since the 2000s. Our research provides novel insights into Arctic marine zooplankton assemblages and serves as a valuable baseline for future ecological monitoring and modeling of the Barents Sea ecosystem in the context of global climate change. Full article

Environmental stress factors, especially salinity, are among the most important abiotic stresses that negatively affect plant production worldwide. High salt levels in irrigation water are a major abiotic stress factor that significantly reduces spinach physiological functioning and production, particularly in irrigated areas. Improving the salt tolerance of spinach is critical for sustainable production, and in this study, we tested the hypothesis that exogenous proline (5 µM), ascorbic acid (1 mM), and salicylic acid (1 mM) applications, applied separately, would reduce salinity stress. These applications were performed at regular 14-day intervals starting from the third true leaf stage. For this purpose, plants were exposed to irrigation water salinities of 0.38, 2.0, 4.0, 7.0, 10.0, and 15.0 dS m⁻¹, and growth, photosynthetic performance, antioxidant enzyme activities, lipid peroxidation, endogenous proline, and mineral contents were assessed. Increasing salinity to 15 dS m⁻¹ decreased leaf area by 53.23% and stomatal conductance by 83.07%, and all these physiological changes were statistically significant. Under salinity conditions, catalase, guaiacol peroxidase, glutathione reductase, glutathione S-transferase, and superoxide dismutase activities increased by 1.13–2.52-fold, while ascorbate peroxidase activity decreased by 59.69%. Malondialdehyde levels increased 6-fold with salinity, indicating enhanced oxidative damage. Consequently, yield decreased by 31% under 15 dS m⁻¹ salinity. Although all exogenous applications alleviated salinity stress, the most significant improvement was observed in proline application. Proline increased yield and chlorophyll content by 9% and 8.5%, respectively, and also increased antioxidant enzyme activities by 24.4–66.7%. Salicylic acid treatment increased the K⁺/Na⁺ ratio by 26.6%, and ascorbic acid treatment increased the Ca²⁺/Na⁺ ratio by 36.6%. Overall, low-dose proline application was found to improve photosynthetic pigment content and stomatal conductance, antioxidant defenses, and ion homeostasis in spinach against salinity stress, providing a stronger protective effect compared to ascorbic acid and salicylic acid. Furthermore, it can be concluded that proline application could be an effective way to manage salinity-induced limitations to physiological processes and yields, providing practical applications for sustainable production under saline irrigation conditions. Full article

Enhancing nitrogen use efficiency (NUE) in cereal crops is a major challenge for dryland systems that rely heavily on synthetic nitrogen (N) inputs. Microbial biostimulants have recently emerged as promising alternatives for cost-effective N inputs in wheat through foliar colonization and endophytic biological N fixation. Methylobacterium symbioticum strain SB23 (also known as BlueN or Utrisha N) is a pink-pigmented, obligately aerobic, Gram-negative, facultative methylotrophic bacterium demonstrated to potentially reduce N chemical fertilization and improve yields in various crops. A field trial consisting of large replicated 2.3 ha plots of Australian Prime Hard (APH) wheat cv. Rockstar was established in south central New South Wales, Australia, to evaluate the foliar application of M. symbioticum strain SB23 under both standard and reduced N regimes for winter wheat maturing in late spring. Application of the SB23 biostimulant significantly increased wheat leaf chlorophyll concentration at 30 and 60 days after application (DAA) and promoted biomass accumulation at 60, 90 and 120 DAA in contrast to the untreated control, with the strongest positive response under reduced N input. Specifically, the 75% N + biostimulant treatment improved biomass by up to 23% and grain yield by 14% relative to the reduced-N control, demonstrating potential supplemental fertility without yield loss. Correlation analyses revealed that mid-season chlorophyll was strongly associated with biomass and carbon assimilation (r = 0.87 and 0.84, respectively), while biomass at 60 DAA was highly correlated with grain spike weight (r = 0.81), suggesting a strong association of improved crop vigor and yield with inoculation. At harvest, SB23 enhanced biomass nitrogen accumulation and nitrogen use efficiency, with the 75%N + biostimulant treatment achieving the highest plant N uptake (25% above the reduced-N control) and the greatest partial factor productivity of nitrogen (51.8 kg grain kg⁻¹ N applied), while both 100%N treatments showed the lowest efficiency. Collectively, these findings suggest that Methylobacterium symbioticum SB23 improves NUE through enhanced crop performance thereby providing a supplementary N source and delivering a cost–benefit advantage of approximately A$170 ha⁻¹ under reduced N application. Full article

Pharmaceuticals are increasingly recognized as emerging contaminants with potential impacts on agroecosystems. Among these, antibiotics such as ciprofloxacin (CPX) persist in wastewater and may enter agricultural soils through irrigation or fertilization practices, yet their effects on crop plants remain poorly understood. This study evaluated the phytotoxic effects of ciprofloxacin on early growth and photosynthetic pigment content in purple maize (Zea mays L.), a variety of nutritional and cultural importance. Seeds were germinated in an agar-based medium (0.5%) and exposed to three concentrations of ciprofloxacin (3, 10, and 30 mg·L⁻¹) for seven days under controlled conditions. Germination percentage, seedling fresh weight, organ length (root, stem, and leaf), and photosynthetic pigment concentrations (chlorophylls a and b, and carotenoids) were determined. Ciprofloxacin exposure resulted in dose-dependent reductions in germination (from 83% at 3 mg·L⁻¹ to 50% at 30 mg·L⁻¹) and root elongation, while stem length remained unaffected. Chlorophyll content decreased with increasing ciprofloxacin concentration, with the lowest values observed at 30 mg·L⁻¹, while carotenoid levels remained stable, with no statistically significant differences observed. Although ciprofloxacin is typically detected in environmental matrices at ng–µg L⁻¹ levels, higher concentrations may occur in localized contamination hotspots; ciprofloxacin affected early developmental and physiological processes in maize under these elevated exposure conditions. These findings highlight the importance of integrating phytotoxicity assessments into agricultural ecopharmacovigilance strategies and contribute to understanding the risks associated with pharmaceutical contamination in crop production systems. Full article

Henan Province, the foremost wheat-producing region in China, frequently experiences drought stress during the wheat seedling stage. Innovating the evaluation methods for drought resistance at this stage and identifying drought-resistant varieties are crucial for the effective utilization of germplasm. This study utilized 55 wheat varieties that have been bred and promoted in Henan Province in recent years as experimental materials. A 15% PEG-6000 solution was employed to simulate drought stress, and the primary morphological indicators of seedlings, relative chlorophyll content (SPAD), and various chlorophyll fluorescence parameters were assessed. The comprehensive drought resistance scores (D values) for each variety were determined by calculating the drought resistance coefficients for each index, employing principal component analysis, and conducting membership function analysis. Based on the cluster analysis of D values, 55 varieties were categorized into four groups: high drought resistance (10), medium drought resistance (28), low drought resistance (16), and drought-sensitive (1). Seven indicators—SPAD, fresh root weight, seedling height, fresh weight of the aboveground part, Fv/Fm, PItotal, and Mo—were selected as evaluation metrics for the drought resistance of wheat through stepwise regression analysis. The comprehensive evaluation system developed in this study, which is based on morphological and photosynthetic fluorescence characteristics, can swiftly and accurately assess the drought resistance of wheat seedlings. The key indicators identified for highly drought-resistant varieties may serve as valuable references for drought-resistant wheat breeding in Henan Province. Full article

Increasing domestic sewage production associated with urban population growth poses environmental challenges. Biosolids from wastewater treatment can recycle nutrients in agriculture, while plant growth-promoting rhizobacteria (PGPR) enhance nutrient availability and plant performance. This study evaluated the effects of the combined application of sewage sludge–derived biosolid and Bacillus aryabhattai on sunflower growth, biomass production, physiological traits, and nutrient status during the early growth stage under greenhouse conditions. We hypothesized that this combined treatment would enhance plant performance compared with biosolid application alone. Four treatments were established: control (T1), 5 g of biosolid alone (T2), 5 g biosolid + 3.2 mL B. aryabhattai (T3), and 5 g biosolid + 6.4 mL B. aryabhattai (T4). The formulation contains B. aryabhattai strain CMAA 1363 (1 × 10${}^8$ CFU mL${}^{-1}$) as the active microbial component, together with humic substances and other formulation agents (thickener, preservative, and water). The Plants were grown for 44 days. The data were analyzed using one-way ANOVA followed by mean comparison among treatments. Shoot dry mass was significantly higher in T4 compared with the T1 and T2 (p < 0.001), while no significant difference was observed between T3 and T4 (p > 0.05). Biosolid application increased the photosynthetic rate, and its combination with B. aryabhattai further enhanced photosynthetic performance, with significant difference detected between bacterial doses only at the end of growth period. Substomatal CO${}_2$ concentration was lower in inoculated treatments, indicating greater CO${}_2$ assimilation efficiency. Total chlorophyll increased with the addition of sludge and further increased by inoculation with 6.4 mL. Leaf N, Mn, and Zn contents were highest in T4. Overall, the combined application of biosolid and B. aryabhattai improved photosynthetic efficiency and biomass accumulation, highlighting the potential of integrating biosolids and beneficial rhizobacteria as a sustainable approach for nutrient recycling and improved crop productivity in agricultural systems. Full article