Search Results (419)

Global atmospheric N₂O concentrations have risen to 335 ppb, with agricultural soils serving as a major emission source and rice paddies accounting for approximately 11% of agricultural N₂O emissions. Rice–crab co-culture has been widely adopted because of its potential to increase and stabilize crop yields; however, the underlying mechanisms of N₂O mitigation and the synergistic effects of crab bioturbation with water and nitrogen management remain unclear. Therefore, in this study, we conducted a two-year field experiment in Zhaodong, Heilongjiang Province, China, to elucidate the N₂O mitigation effects of rice–crab co-culture under water and nitrogen regulation and the associated driving mechanisms. The results showed that rice–crab co-culture significantly reduced N₂O emissions. Specifically, the N₂O flux decreased by 19.9%, while cumulative N₂O emissions decreased by 19.8%. Under the combined regulation of water and nitrogen management, the mitigation effect on N₂O emissions was further enhanced, with a reduction of up to 30.8%. Regarding environmental factors, crab activity combined with shallow wet irrigation reduced soil water content and increased surface temperature. These changes promoted the transformation of nitrogen from inorganic forms to microbially assimilable forms, increasing the microbial nitrogen content by approximately 29.5%. Meanwhile, soil enzyme activities changed significantly: the activities of urease, sucrase, and protease increased, whereas nitrate reductase activity decreased. Structural equation modeling showed that the indirect effect of management practices was much greater than the direct effect, accounting for 63% of the total effect. Nitrogen transformation was the core mitigation pathway, characterized by the conversion of inorganic nitrogen into microbial biomass nitrogen, which reduced substrate availability for nitrification and denitrification. Enzyme activity regulation served as a secondary pathway, mainly through the inhibition of nitrate reductase activity. Overall, the rice–crab system achieved sustained N₂O reduction by improving soil aeration and jointly regulating substrate limitation and weakening nitrogen transformation capacity. Full article

Wind energy resource assessment in complex terrain regions requires high-resolution data and multidimensional risk evaluation beyond conventional wind speed climatology. This study uses a 40-year (1979–2018) WRF dynamical downscaling dataset assimilating over 2400 surface stations to assess wind power potential, long-term trends, diurnal characteristics, and extreme ramp events across nine terrain-defined wind zones in Xinjiang, Northwestern China. The capacity factor, equivalent full-load hours, and wind power density are computed at 100 m hub height and validated against 105 long-term stations. The domain-mean annual capacity factor is 0.08, but resources are concentrated in mountain-pass corridors where core-zone values reach 0.35–0.45. Seasonal asymmetry is pronounced: the windy season (April–August) contributes 57–69% of annual output depending on zone. Long-term trends are spatially differentiated, with a significant decline in southern basin zones and a significant increase in northern zones after 2006. Diurnal capacity factor profiles differ by zone type—nocturnal peaks in basin-margin corridors versus midday peaks in thermally driven passes—and remain phase-stable across four decades. Extreme ramp events concentrate in the windy season and decline in frequency after 2006, and sensitivity tests show that the main spatial pattern remains robust under 5%, 10%, and 15% hourly capacity factor change thresholds. These findings provide a quantitative basis for zone-specific wind power planning, storage sizing, and wind–solar complementarity strategies in arid continental regions with complex topography. Full article

Micro-dwarf tomato cultivars are increasingly considered for urban and controlled-environment agriculture due to their compact architecture and suitability for high-density planting. In this study, we evaluated the effects of different leaf removal intensities on leaf-level physiological performance, fruit yield, and fruit quality in three micro-dwarf tomato cultivars (Mohamed, Hahms Gelbe Topftomate, and Red Robin) grown under contrasting seasonal light conditions. Plants were subjected to low (15%), moderate (30%), or severe (90%) leaf removal, and leaf-level gas exchange was measured across canopy layers, along with yield and fruit quality assessments. Severe leaf removal (90%) increased carbon assimilation, transpiration, and stomatal conductance in middle and lower canopy leaves by up to approximately twofold compared with control plants, indicating improved light availability at the leaf level. However, these physiological enhancements did not consistently translate into higher yield, reflecting reduced whole-plant source capacity under excessive leaf removal. Low to moderate leaf removal (15–30%) generally increased or maintained yield and fruit number, whereas severe leaf removal reduced yield in Hahms Gelbe and Red Robin, particularly under low seasonal radiation. Fruit quality was largely unaffected by leaf removal, except for total soluble solids, which declined by approximately 12% under severe leaf removal across cultivars, consistent with sugar dilution under source limitation. Overall, these results demonstrate that optimal leaf removal in micro-dwarf tomatoes requires balancing improved canopy light distribution with maintenance of sufficient leaf area for carbon assimilation. For the tested compact canopies, LR15–30% represented a generally safe, practical range, whereas LR90% posed a substantial risk of source limitation, particularly at lower radiation; the exact threshold, however, remained cultivar- and light-dependent. Full article

Extreme flooding has emerged as a major climate risk for low-lying Australian macadamia (Macadamia spp.) orchards, yet the physiological mechanisms underlying tree decline remain poorly understood. We investigated whole-plant responses to complete submergence in young, grafted macadamia trees by subjecting plants to one- and two-week floods, as well as repeated flooding. Following emergence from the flood water, photosynthetic rate (A) and stomatal conductance (g_s) declined progressively with increased flood duration and repeated exposure. Grafted plants of G on H2 maintained a more resilient photosynthetic apparatus post-flood than G grafted on Beaumont, as reflected by a smaller decline in maximum assimilation rates as well as biochemical capacities for ribulose 1,5 bisphosphate (RuBP) carboxylation (V_cmax), and RuBP regeneration (J_max). Despite these differences in leaf-level function, prolonged and repeated flooding triggered a cascade of post-flood stress symptoms in both rootstocks, including progressive canopy dieback, sharp reductions in root biomass, depletion of total non-structural carbohydrates, and ultimately scion mortality. Collectively, these findings indicate that plants only partially tolerated one week of complete submergence, whereas longer or repeated flooding severely compromised carbon balance and plant survival in both rootstocks. Full article

Winter wheat production in the extremely arid oasis region of Xinjiang relies heavily on irrigation and fertilization, but conventional high-input management can induce luxury transpiration and non-productive water consumption, limiting the coordinated improvement of grain yield, water use efficiency (WUE), and economic benefits. To identify the threshold at which water–fertilizer inputs shift from efficient use to inefficient water consumption and to define a robust management range, a two-year field experiment was conducted in southern Xinjiang during the 2022–2023 and 2023–2024 growing seasons. Four irrigation levels, corresponding to 60%, 80%, 100%, and 120% of crop evapotranspiration (ET_c), and four fertilization levels were established to evaluate the effects of water–fertilizer interactions on canopy development, leaf gas exchange, evapotranspiration, yield, WUE, and economic benefits. Appropriate water and nutrient supply promoted canopy establishment and maintained higher photosynthetic capacity, thereby increasing grain yield, WUE, and net return. However, excessive inputs weakened yield gains and failed to synchronously improve WUE and economic benefits. Linear plateau models revealed clear thresholds in both the crop-stand scale evapotranspiration (ET)–dry matter accumulation (DM) relationship and the leaf-scale transpiration rate (Tr)–net photosynthetic rate (Pn) relationship. The seasonal ET thresholds were 504.59 and 553.87 mm in the two growing seasons, respectively, and the Tr threshold was 4.83 mmol m⁻² s⁻¹. Beyond these thresholds, additional water consumption was not effectively converted into photosynthetic assimilation or biomass accumulation, indicating luxury transpiration. Year-specific response surface analysis and TOPSIS evaluation showed that I3F3, namely 100% ET_c combined with 210–195–75 kg ha⁻¹ N–P₂O₅–K₂O, together with its adjacent range, sustained high grain yield, WUE, and economic benefits, with I3F3 achieving the best overall performance in both years. The intersection of the two-year high-performance regions further defined a robust interannual feasible range with an irrigation amount of 506.21–545.09 mm and a total fertilizer input of 369.54–628.33 kg ha⁻¹. Overall, maintaining water and fertilizer inputs within the I3F3-adjacent range can reduce non-productive water consumption and luxury transpiration risk while synergistically improving grain yield, WUE, and economic benefits in winter wheat. Full article

Solanum lycopersicum is highly sensitive to water deficits, which negatively affect photosynthesis and increase oxidative stress. Although chitosan nanoparticles (ChNPs) offer a sustainable solution, research on their effects on this species is scarce. This study evaluated whether ChNPs mitigate the physiological and biochemical effects of water deficit on S. lycopersicum seedlings. Thirty-day-old seedlings were grown under greenhouse conditions, and two irrigation levels were established: 80% of substrate water-holding capacity (well-watered, WW), and 50% of water-holding capacity (mild-to-moderate water deficit, WD). Spherical ChNPs with a size of 39.52 ± 10.9 nm were suspended in 1% acetic acid and foliar-applied at 0, 60, or 120 mg L⁻¹. After 10 days, biomass accumulation, chlorophyll fluorescence parameters (F_v′/F_m′, ΦPSII, and ETR), gas exchange, and non-enzymatic antioxidant traits were determined. Even under this early-stage stress regime, water deficit significantly reduced shoot and root biomass, net photosynthesis, and stomatal conductance, while increasing lipid peroxidation. Foliar application of ChNPs, particularly at 60 mg L⁻¹, restored dry matter production and improved photochemical efficiency and electron transport rate by 14%; likewise, net CO₂ assimilation increased by 11.7%. In addition, this dose enhanced antioxidant activity and total phenols by 66% and 1.6-fold, respectively. ChNPs at 60 mg L⁻¹ mitigated the effects of WD in S. lycopersicum by increasing antioxidant and photosynthetic performances. Nevertheless, additional molecular studies, including enzymatic antioxidant characterization and compatible solute profiling, are required to elucidate the mechanisms involved. Full article

Tomato yellow leaf curl virus (TYLCV) is one of the most destructive viral diseases causing severe yield losses in tomato production worldwide. This study investigated the effects of TYLCV infection on plant growth, photosynthetic physiological responses, and yield formation in greenhouse-grown tomatoes and evaluated the applicability of physiological trait-based yield prediction models. Two large-fruited tomato cultivars widely cultivated in Korean protected horticulture systems, ‘Daphnis’ and ‘Pink Star’, were inoculated with TYLCV under greenhouse conditions, and their growth, physiological responses, and yield characteristics were compared under high- and low-temperature growing seasons. TYLCV infection significantly reduced leaf length, leaf width, and leaf area index (LAI), and decreased both flowering truss number and fruit-setting truss number, resulting in reduced total yield. Physiological analyses showed that infected plants exhibited decreases in the OJIP fluorescence rise curve and Fv/Fm values, indicating a reduced photochemical efficiency in photosystem II. In addition, A–Ci response curve analysis revealed a reduction in net photosynthetic rate, suggesting limited carbon assimilation capacity. Total yield showed significant positive correlations with maximum net photosynthetic rate (Amax), Fv/Fm, and Ci300. GGE and GT biplot analyses further indicated that yield was closely associated with photosynthetic performance and canopy development traits. A multiple regression model based on physiological traits and virus infection status explained a significant proportion of the variation in tomato yield (R² = 0.367), indicating that TYLCV infection acts as a key limiting factor for yield reduction. These findings demonstrate that TYLCV infection restricts tomato productivity through reduced photosynthetic efficiency and altered canopy structure. Moreover, physiological trait-based yield prediction approaches may provide a useful framework for evaluating productivity under viral infection conditions and for developing data-driven crop management strategies in greenhouse tomato production systems. Full article

The aim of this research was to quantify the capacity of different shrub species to remove atmospheric CO₂, to adsorb particulate matter and to dissipate latent heat through transpiration. A total of 308 established plants comprising Deutzia scabra, Elaeagnus × ebbingei, Euonymus japonicus, Forsythia × intermedia, Laurus nobilis, Ligustrum vulgare, Pittosporum tobira, Prunus laurocerasus and Viburnum tinus were selected in Lugano (Switzerland) and Bolzano (Italy). Stem diameter, crown radius, Leaf Area Index, net CO₂ assimilation per unit leaf area (A_leaf), transpiration, and stomatal conductance (g_s) were measured during spring, summer, and fall. The net CO₂ assimilation per unit of crown projection area and per plant were calculated by upscaling A_leaf using a multilayer model. Latent heat dissipation was calculated using the Penman–Monteith equation. The amount of PM trapped on leaves was measured using a gravimetric method. Differences in leaf area and leaf gas exchange among species affected their capacity to deliver specific ecosystem services. Forsythia, Pittosporum, Elaeagnus and Deutzia removed about 40% more CO₂ per unit crown projection area than Laurus, Ligustrum, and Euonymus. Latent heat dissipation by shrubs was, on average, 130 W m⁻², which is comparable to that of tree species. PM removal per unit leaf area was higher in species with sparse canopies and rough leaf surfaces. Full article

Black locust (Robinia pseudoacacia L.) has exceptional growth capacity in nutrient-poor environments and is therefore widely used for afforestation and land reclamation on degraded soils. However, drought stress can restrict sapling growth, which undermines the success of their establishment. The effect of a product containing two endophytic strains (Trichoderma afroharzianum P. Chaverri, F.B. Rocha, Degenkolb & Druzhinina TR04 and Trichoderma simmonsii P. Chaverri, F.B. Rocha, Degenkolb & Druzhinina TR05) was studied on a black locust sapling stand under severe drought in eastern Hungary. The two-year-old saplings were root-soaked before planting in sandy soil. The growth of Trichoderma-treated plants improved by late spring. Compared to the control trees, average height increased by 25.75%, and root collar diameter was 21.96% larger. Treated plants also showed 9.1% higher chlorophyll content and 11.1% Normalized Difference Vegetation Index (NDVI). The reduced intercellular CO₂ concentration, together with slightly lower stomatal conductance and increased transpiration rate, suggests tighter stomatal regulation and altered water-use dynamics under drought conditions. These responses indicate improved short-term drought acclimation rather than enhanced carbon assimilation capacity. Pre-planting inoculation with endophytic Trichoderma strains provides a sustainable method to enhance the early establishment and drought resilience of black locust, thereby increasing the efficacy of forest restoration by improving the survival of black locust on challenging degraded sites. Full article

Motor imagery (MI)-based brain–computer interfaces (BCIs) provide an intuitive pathway for neural interaction and rehabilitation, yet their practical deployment remains constrained by long calibration requirements, substantial inter-subject variability, and the non-stationary nature of EEG signals. These challenges are amplified when using dry-electrode EEG, which offers superior convenience for real-world systems but produces noisier and less stable recordings than traditional wet electrodes. As a result, online or real-time four-class MI detection—especially with dry electrodes—has been explored only in a limited number of studies, underscoring an important gap in the field and the need for adaptive, intelligent models capable of coping with continuous signal drift. In this study, we propose a real-time MI-BCI framework that integrates immersive action observation (AO) in virtual reality with a continual learning strategy to manage the evolving nature of dry-EEG features. A CNN–Transformer hybrid model is first initialized through AO-enhanced pre-training and subsequently refined via online continual adaptation during user interaction. This continual learning mechanism enables the classifier to incrementally assimilate new MI patterns while preserving previously acquired knowledge, thereby mitigating the performance degradation that typically arises in extended MI-BCI sessions. Experimental results across four motor classes demonstrate improved decoding accuracy and strengthened sensorimotor activation over time, confirming the system’s capacity for user-specific and session-to-session adaptation. By addressing the rarely studied combination of dry electrodes, online four-class MI decoding, and continual learning, the proposed approach enhances MI-BCI robustness, reduces calibration burden, and supports sustainable long-term deployment in intelligent neurotechnology applications. Full article

Autotrophic carbon-fixing microbes can assimilate atmospheric carbon dioxide into biomass via the Calvin–Benson–Bassham (CBB) cycle (their primary carbon fixation pathway), thereby reinforcing soil carbon sequestration in the plantation ecosystem; however, the succession of RubisCO-harboring microbial communities across stand ages remains poorly understood. Here, we investigated the community succession of microbes carrying the gene encoding RubisCO, a key enzyme in the CBB cycle, across a stand-age chronosequence in a Picea asperata plantation ecosystem. Our results revealed a progressive decrease in microbial α-diversity and a significant restructuring of community composition with increasing stand age, characterized by an enrichment of Proteobacteria and a concomitant depletion of Actinobacteria. While the Shannon–Wiener index was most strongly correlated with soil total nitrogen content, redundancy analysis identified soil pH as the predominant environmental driver of community turnover, a relationship that was found to be threshold-dependent, with substantial community shifts occurring in response to pH variations of 0.5 to 1.0 units. These findings suggest that sustaining the diversity of RubisCO-harboring microbes in older stands—a process potentially enhanced by soil nitrogen management—provides a viable strategy for augmenting the carbon sequestration capacity of managed forests through targeted microbiome regulation. Full article

This study evaluates nitrogen (N) and phosphorus (P) pollution in the Ankara River Sub-basin, Türkiye, using the grey water footprint (GWF) approach. A Tier-1 GWF approach was applied, complemented by a sensitivity analysis to assess the influence of key parameters, including leaching–runoff fractions and water quality thresholds. The results should be interpreted as indicative rather than absolute values, as they depend on assumptions related to leaching fractions and background concentrations. By integrating data from agricultural diffuse sources and municipal wastewater treatment plants (WWTPs), the research identifies critical pollution hotspots and sectoral pressures on water resources, causing water quality degradation. The results reveal that P is the primary limiting pollutant governing GWF magnitudes across the sub-basin. The total GWF was estimated at 8294 million m³ yr⁻¹ in the sub-basin outlet. Approximately 10% and 31% of the basin-wide GWF were associated with fertilizer-based diffuse sources and WWTP1, respectively. The study demonstrates that regulatory compliance alone does not guarantee the protection of a river’s assimilative capacity. These results provide a basis for policy development, emphasizing the need to move beyond concentration-based regulations toward management frameworks that explicitly consider assimilative capacity and cumulative basin-scale impacts. Full article

Microalgae are among the most efficient photosynthetic organisms on Earth, and their capacity for CO₂ fixation directly links the global carbon cycle with green energy conversion, positioning them as strategic biological platforms for achieving carbon neutrality. This review provides a comprehensive and multiscale synthesis of the engineering and biological mechanisms underlying microalgal CO₂ fixation, integrating perspectives from gas–liquid mass transfer, CO₂ assimilation pathways, key enzymatic systems, metabolic regulation, and environmental control. From an engineering standpoint, we analyze the limitations governing CO₂ transfer from the gas phase to the aqueous phase and critically evaluate intensification strategies aimed at enhancing inorganic carbon availability in cultivation systems. At the biological and biochemical levels, we dissect carbon concentrating mechanisms (CCMs), including C₄-like pathways, and elucidate the structural organization, regulatory properties, and functional coordination of Rubisco and carbonic anhydrase systems. Particular emphasis is placed on the coupling between enzyme-level regulation and metabolic flux redistribution, supported by insights from metabolic flux analysis and systems-level modeling, to establish theoretical and engineering foundations for improving carboxylation efficiency. Finally, we propose an integrated roadmap for the future development of microalgal CO₂ fixation technologies, highlighting the convergence of synthetic biology, artificial intelligence, and systems engineering to achieve end-to-end optimization from molecular mechanisms to reactor-scale performance, while enabling the valorization of waste gas streams and circular carbon utilization. This review aims to provide a coherent theoretical framework and forward looking perspective for the development of efficient, intelligent, and sustainable microalgal CO₂ fixation systems. Full article

Light availability is a key environmental factor regulating nitrogen assimilation, carbon metabolism, and nutritional quality in leafy vegetables grown in controlled environments. However, how practical lighting regimes used in plant factories with artificial lighting (PFALs) influence the coordination between nitrogen assimilation and central carbon metabolism across different lettuce cultivar types remains insufficiently understood. This study investigated how moderate differences in photosynthetic photon flux density (PPFD) influence nitrogen metabolism and metabolic coordination in hydroponically cultivated lettuce. Two cultivars representing contrasting morphological types, iceberg lettuce (‘Celebration’) and leaf lettuce (‘Sunny’), were grown under LED light intensities of 150 and 200 µmol·m⁻²·s⁻¹. Nitrate, nitrite, and ammonium concentrations were measured together with the activities of nitrate reductase (NRA) and nitrite reductase (NiRA), as well as ascorbic acid content. Metabolomic profiling was additionally performed to characterize broader metabolic responses. Higher light intensity enhanced nitrate reduction capacity in both cultivars, but the resulting patterns of nitrogen accumulation were strongly genotype-dependent. The leaf lettuce cultivar ‘Sunny’ exhibited increased NRA and reduced nitrate accumulation under higher light intensity, whereas the iceberg lettuce cultivar ‘Celebration’ accumulated more nitrate under the same conditions. Ammonium responses further suggested differences in downstream nitrogen assimilation processes. Elevated light intensity also increased ascorbic acid levels in both cultivars. Metabolomic analysis revealed contrasting cultivar-specific shifts in central carbon metabolism, particularly involving soluble sugars and tricarboxylic acid cycle intermediates, indicating differential coordination between carbon metabolism and nitrogen utilization. Overall, these findings demonstrate that moderate changes in light intensity within the practical PFAL cultivation range can significantly influence the integration of carbon and nitrogen metabolism in lettuce. Importantly, cultivar-specific physiological traits determine how these metabolic responses translate into nitrate accumulation and nutritional quality in controlled-environment production systems. Full article

Understanding of carrot growth dynamics and ecophysiological functioning in tropical highland environments remains limited, despite the crop’s productive importance in the Colombian Andean region. This study aimed to characterize biomass accumulation and partitioning, as well as the photosynthetic response to radiation, in two carrot (Daucus carota L.) cultivars (Berlicum- and Flakkee-type) grown under high-altitude Andean tropical conditions in Rionegro, Antioquia. To account for field spatial heterogeneity, four beds were used as blocks, and both cultivars were evaluated in parallel under comparable field conditions. Weekly destructive samplings were performed to quantify total dry biomass, shoot biomass, root biomass, leaf number, and leaf area. In addition, the response of net CO₂ assimilation to photosynthetically active radiation was evaluated using a portable gas-exchange system. Total and root biomass were described using logistic models, shoot biomass using a Gaussian model, and the photosynthetic response using an exponential model. Berlicum showed higher biomass accumulation, whereas Flakkee exhibited an earlier response of growth and photosynthetic activity. In both cultivars, the highest functional capacity was concentrated in stage III, coinciding with the strengthening of the storage-root sink. Overall, the results indicate contrasting temporal patterns in biomass partitioning and photosynthetic performance between the two carrot cultivars and provide a useful ecophysiological framework for interpreting crop management and harvest timing under high-altitude Andean tropical conditions. Full article