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16 pages, 1526 KiB  
Article
Effects of Different Phosphorus Addition Levels on Physiological and Growth Traits of Pinus massoniana (Masson Pine) Seedlings
by Zhenya Yang and Hui Wang
Forests 2025, 16(8), 1265; https://doi.org/10.3390/f16081265 (registering DOI) - 2 Aug 2025
Abstract
Soil phosphorus (P) availability is an important determinant of productivity in Pinus massoniana (Masson pine) forests. The mechanistic bases governing the physiological and growth responses of Masson pine to varying soil P conditions remain insufficiently characterized. This study aims to decipher the adaptive [...] Read more.
Soil phosphorus (P) availability is an important determinant of productivity in Pinus massoniana (Masson pine) forests. The mechanistic bases governing the physiological and growth responses of Masson pine to varying soil P conditions remain insufficiently characterized. This study aims to decipher the adaptive strategies of Masson pine to different soil P levels, focusing on root morphological–architectural plasticity and the allocation dynamics of nutrient elements and photosynthetic assimilates. One-year-old potted Masson pine seedlings were exposed to four P addition treatments for one year: P0 (0 mg kg−1), P1 (25 mg kg−1), P2 (50 mg·kg−1), and P3 (100 mg kg−1). In July and December, measurements were conducted on seedling organ biomass, root morphological indices [root length (RL), root surface area (RSA), root diameter (RD), specific root length (SRL), and root length ratio (RLR) for each diameter grade], root architectural indices [number of root tips (RTs), fractal dimension (FD), root branching angle (RBA), and root topological index (TI)], as well as the content of nitrogen (N), phosphorus (P), carbon (C), and non-structural carbohydrates (NSCs) in roots, stems, and leaves. Compared with the P0 treatment, P2 and P3 significantly increased root biomass, root–shoot ratio, RL, RSA, RTs, RLR of finer roots (diameter ≤ 0.4 mm), nutrient accumulation ratio in roots, and starch (ST) content in roots, stems and leaves. Meanwhile, they decreased soluble sugar (SS) content, SS/ST ratio, C and N content, and N/P and C/P ratios in stems and leaves, as well as nutrient accumulation ratio in leaves. The P3 treatment significantly reduced RBA and increased FD and SRL. Our results indicated that Masson pine adapts to low P by developing shallower roots with a reduced branching intensity and promoting the conversion of ST to SS. P’s addition effectively alleviates growth limitations imposed by low P, stimulating root growth, branching, and gravitropism. Although a sole P addition promotes short-term growth and P uptake, it triggers a substantial consumption of N, C, and SS, leading to significant decreases in N/P and C/P ratios and exacerbating N’s limitation, which is detrimental to long-term growth. Under high-P conditions, Masson pine strategically prioritizes allocating limited N and SS to roots, facilitating the formation of thinner roots with low C costs. Full article
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17 pages, 3193 KiB  
Article
Effects of Nitrogen and Phosphorus Additions on the Stability of Soil Carbon Fractions in Subtropical Castanopsis sclerophylla Forests
by Yunze Dai, Xiaoniu Xu and LeVan Cuong
Forests 2025, 16(8), 1264; https://doi.org/10.3390/f16081264 (registering DOI) - 2 Aug 2025
Abstract
Soil organic carbon (SOC) pool plays an extremely important role in regulating the global carbon (C) cycle and climate change. Atmospheric nitrogen (N) and phosphorus (P) deposition caused by human activities has significant impacts on soil C sequestration potential of terrestrial ecosystem. To [...] Read more.
Soil organic carbon (SOC) pool plays an extremely important role in regulating the global carbon (C) cycle and climate change. Atmospheric nitrogen (N) and phosphorus (P) deposition caused by human activities has significant impacts on soil C sequestration potential of terrestrial ecosystem. To investigate the effects of N and P deposition on soil C sequestration and C-N coupling relationship in broad-leaved evergreen forests, a 6-year field nutrient regulation experiment was implemented in subtropical Castanopsis sclerophylla forests with four different N and P additions: N addition (100 kg N·hm−2·year−1), N + P (100 kg N·hm−2·year−1 + 50 kg P·hm−2·year−1), P addition (50 kg P·hm−2·year−1), and CK (0 kg N·hm−2·year−1). The changes in the C and N contents and stable isotope distributions (δ13C and δ15N) of different soil organic fractions were examined. The results showed that the SOC and total nitrogen (STN) (p > 0.05) increased with N addition, while SOC significantly decreased with P addition (p < 0.05), and N + P treatment has low effect on SOC, STN (p > 0.05). By density grouping, it was found that N addition significantly increased light fraction C and N (LFOC, LFN), significantly decreased the light fraction C to N ratio (LFOC/N) (p < 0.05), and increased heavy fraction C and N (HFOC, HFN) accumulation and light fraction to total organic C ratio (LFOC/SOC, p > 0.05). Contrary to N addition, P addition was detrimental to the accumulation of LFOC, LFN and reduced LFOC/SOC. It was found that different reactive oxidized carbon (ROC) increased under N addition but ROC/SOC did not change, while N + P and P treatments increased ROC/SOC, resulting in a decrease in SOC chemical stability. Stable isotope analysis showed that N addition promoted the accumulation of new soil organic matter, whereas P addition enhanced the transformation and utilization of C and N from pre-existing organic matter. Additionally, N addition indirectly increased LFOC by significantly decreasing pH; significantly contributed to LFOC and ROC by increasing STN accumulation promoted by NO3-N and NH4+-N; and decreased light fraction δ13C by significantly increasing dissolved organic C (p < 0.05). P addition had directly significant negative effect on LFOC and SOC (p < 0.05). In conclusion, six-year N deposition enhances soil C and N sequestration while the P enrichment reduces the content of soil C, N fractions and stability in Castanopsis sclerophylla forests. The results provide a scientific basis for predicting the soil C sink function of evergreen broad-leaved forest ecosystem under the background of future climate change. Full article
(This article belongs to the Section Forest Soil)
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20 pages, 3604 KiB  
Article
Analysis of the Differences in Rhizosphere Microbial Communities and Pathogen Adaptability in Chili Root Rot Disease Between Continuous Cropping and Rotation Cropping Systems
by Qiuyue Zhao, Xiaolei Cao, Lu Zhang, Xin Hu, Xiaojian Zeng, Yingming Wei, Dongbin Zhang, Xin Xiao, Hui Xi and Sifeng Zhao
Microorganisms 2025, 13(8), 1806; https://doi.org/10.3390/microorganisms13081806 (registering DOI) - 1 Aug 2025
Abstract
In chili cultivation, obstacles to continuous cropping significantly compromise crop yield and soil health, whereas crop rotation can enhance the microbial environment of the soil and reduce disease incidence. However, its effects on the diversity of rhizosphere soil microbial communities are not clear. [...] Read more.
In chili cultivation, obstacles to continuous cropping significantly compromise crop yield and soil health, whereas crop rotation can enhance the microbial environment of the soil and reduce disease incidence. However, its effects on the diversity of rhizosphere soil microbial communities are not clear. In this study, we analyzed the composition and characteristics of rhizosphere soil microbial communities under chili continuous cropping (CC) and chili–cotton crop rotation (CR) using high-throughput sequencing technology. CR treatment reduced the alpha diversity indices (including Chao1, Observed_species, and Shannon index) of bacterial communities and had less of an effect on fungal community diversity. Principal component analysis (PCA) revealed distinct compositional differences in bacterial and fungal communities between the treatments. Compared with CC, CR treatment has altered the structure of the soil microbial community. In terms of bacterial communities, the relative abundance of Firmicutes increased from 12.89% to 17.97%, while the Proteobacteria increased by 6.8%. At the genus level, CR treatment significantly enriched beneficial genera such as RB41 (8.19%), Lactobacillus (4.56%), and Bacillus (1.50%) (p < 0.05). In contrast, the relative abundances of Alternaria and Fusarium in the fungal community decreased by 6.62% and 5.34%, respectively (p < 0.05). Venn diagrams and linear discriminant effect size analysis (LEfSe) further indicated that CR facilitated the enrichment of beneficial bacteria, such as Bacillus, whereas CC favored enrichment of pathogens, such as Firmicutes. Fusarium solani MG6 and F. oxysporum LG2 are the primary chili root-rot pathogens. Optimal growth occurs at 25 °C, pH 6: after 5 days, MG6 colonies reach 6.42 ± 0.04 cm, and LG2 5.33 ± 0.02 cm, peaking in sporulation (p < 0.05). In addition, there are significant differences in the utilization spectra of carbon and nitrogen sources between the two strains of fungi, suggesting their different ecological adaptability. Integrated analyses revealed that CR enhanced soil health and reduced the root rot incidence by optimizing the structure of soil microbial communities, increasing the proportion of beneficial bacteria, and suppressing pathogens, providing a scientific basis for microbial-based soil management strategies in chili cultivation. Full article
(This article belongs to the Section Microbiomes)
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16 pages, 3753 KiB  
Article
Elevational Patterns and Seasonal Dynamics of Soil Organic Carbon Fractions and Content in Rice Paddies of Yuanyang Terrace, Southwest China
by Haitao Li, Linxi Chang, Yonglin Wu, Yang Li, Xinran Liang, Fangdong Zhan and Yongmei He
Agronomy 2025, 15(8), 1868; https://doi.org/10.3390/agronomy15081868 - 1 Aug 2025
Abstract
Soil organic carbon (SOC) is an important part of the global C pool and is sensitive to climate change. The SOC content and fractions of rice paddies along four elevations (250, 1150, 1600 and 1800 m) on the same slope in four seasons [...] Read more.
Soil organic carbon (SOC) is an important part of the global C pool and is sensitive to climate change. The SOC content and fractions of rice paddies along four elevations (250, 1150, 1600 and 1800 m) on the same slope in four seasons (spring, summer, autumn and winter) at Yuanyang Terrace in southwest China were investigated, and their relationship with environmental factors was analyzed. The contents of SOC, unprotected SOC (uPOM), physically protected SOC (pPOM) and biochemically protected SOC (bcPOM) in rice paddies at a low elevation (250 m), were significantly lower by 49–51% than those at relatively high elevations (1600 m and 1800 m). Among the SOC fractions, the highest proportion (33–50%) was uPOM, followed by pPOM and bcPOM (accounting for 17–40%), and the lowest proportion was chemically protected SOC (cPOM). In addition, there were interseasonal differences among the contents of SOC fractions, with a significantly higher content of SOC, uPOM and pPOM at an elevation of 1600 m in summer than in the other three seasons, whereas the cPOM content at an elevation of 250 m in spring was significantly higher than in the other three higher elevations. According to the redundancy analysis (RDA), total nitrogen was the key environmental factor, with an explanatory degree of 56% affecting the contents of SOC and its fractions. Thus, the SOC content increased with increasing elevation, and physical and biochemical protection were potential stabilization mechanisms responsible for their stability in the rice paddy of Yuanyang Terrace. These results provides empirical evidence for the elevational distribution patterns and seasonal dynamics of SOC fractions in rice paddies across Yuanyang Terrace. These findings highlight the importance of physical and biochemical protection mechanisms in stabilizing SOC in rice paddies, which could enhance long-term C sequestration and contribute to climate change mitigation in terraced agroecosystems. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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21 pages, 4076 KiB  
Article
Tissue Paper-Based Hydrogels for Soil Water Maintenance and Nitrogen Release
by Ana Carla Kuneski, Hima Haridevan, Elena Ninkovic, Ena McLeary, Darren Martin and Gunnar Kirchhof
Gels 2025, 11(8), 599; https://doi.org/10.3390/gels11080599 (registering DOI) - 1 Aug 2025
Abstract
Hydrogels are widely known for their ability to increase soil water retention and for their potential slow nutrient release mechanism. They have been constantly improved to meet the growing demand for sustainability in agriculture. Research focused on the development of biodegradable hydrogels, produced [...] Read more.
Hydrogels are widely known for their ability to increase soil water retention and for their potential slow nutrient release mechanism. They have been constantly improved to meet the growing demand for sustainability in agriculture. Research focused on the development of biodegradable hydrogels, produced from industrial cellulose waste, are an ecological and efficient alternative soil ameliorant for the improvement of agricultural land. The objective of this study was to evaluate the impacts of two types of hydrogel (processed in a glass reactor versus a twin-screw extruder) on soils with different textures (clay and sandy loam), testing their water retention capacity, nitrogen leaching, and effects on seed germination. The methodology included the evaluation of water retention capacity at different pressures with different hydrogel addition rates in the soil, leaching tests in columns filled with soil and hydrogel layers, and germination tests of sorghum and corn. The results indicated that the addition of hydrogel significantly improved water retention, especially in sandy loam soils. The hydrogels also reduced nitrogen leaching, acting as nitrification inhibitors and limiting the conversion of ammonium to nitrate, with greater effectiveness in clayey soils. In the tested formulations, it was observed that the hydrogel doses applied to the columns favored nitrogen retention in the region close to the roots, directly influencing the initial stages of germination. This behavior highlights the potential of hydrogels as tools for directing nutrients in the soil profile, indicating that adjustments to the C:N ratio, nutrient release rate, and applied doses can optimize their application for different crops. Full article
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21 pages, 1603 KiB  
Article
Reactivity of Ammonia in 1,2-Addition to Group 13 Imine Analogues with G13–P–Ga Linkages: The Electronic Role of Group 13 Elements
by Zheng-Feng Zhang and Ming-Der Su
Molecules 2025, 30(15), 3222; https://doi.org/10.3390/molecules30153222 (registering DOI) - 31 Jul 2025
Abstract
Using density functional theory (M06-2X-D3/def2-TZVP), we investigated the 1,2-addition reactions of NH3 with a series of heavy imine analogues, G13=P-Rea (where G13 denotes a Group 13 element; Rea = reactant), featuring a mixed G13–P–Ga backbone. Theoretical analyses revealed that the bonding nature [...] Read more.
Using density functional theory (M06-2X-D3/def2-TZVP), we investigated the 1,2-addition reactions of NH3 with a series of heavy imine analogues, G13=P-Rea (where G13 denotes a Group 13 element; Rea = reactant), featuring a mixed G13–P–Ga backbone. Theoretical analyses revealed that the bonding nature of the G13=P moiety in G13=P-Rea molecules varies with the identity of the Group 13 center. For G13=B, Al, Ga, and In, the bonding is best described as a donor–acceptor (singlet–singlet) interaction, whereas for G13 = Tl, it is characterized by an electron-sharing (triplet–triplet) interaction. According to our theoretical studies, all G13=P-Rea species—except the Tl=P analogue—undergo 1,2-addition with NH3 under favorable energetic conditions. Energy decomposition analysis combined with natural orbitals for chemical valence (EDA–NOCV), along with frontier molecular orbital (FMO) theory, reveals that the primary bonding interaction in these reactions originates from electron donation by the lone pair on the nitrogen atom of NH3 into the vacant p-π* orbital on the G13 center. In contrast, a secondary, weaker interaction involves electron donation from the phosphorus lone pair of the G13=P-Rea species into the empty σ* orbital of the N–H bond in NH3. The calculated activation barriers are primarily governed by the deformation energy of ammonia. Specifically, as the atomic weight of the G13 element increases, the atomic radius and G13–P bond length also increase, requiring a greater distortion of the H2N–H bond to reach the transition state. This leads to a higher geometrical deformation energy of NH3, thereby increasing the activation barrier for the 1,2-addition reaction involving these Lewis base-stabilized, heavy imine-like G13=P-Rea molecules and ammonia. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 3rd Edition)
17 pages, 458 KiB  
Article
Effects of Chestnut Tannin Extract on Enteric Methane Emissions, Blood Metabolites and Lactation Performance in Mid-Lactation Cows
by Radiša Prodanović, Dušan Bošnjaković, Ana Djordjevic, Predrag Simeunović, Sveta Arsić, Aleksandra Mitrović, Ljubomir Jovanović, Ivan Vujanac, Danijela Kirovski and Sreten Nedić
Animals 2025, 15(15), 2238; https://doi.org/10.3390/ani15152238 - 30 Jul 2025
Viewed by 74
Abstract
Dietary tannin supplementation represents a potential strategy to modulate rumen fermentation and enhance lactation performance in dairy cows, though responses remain inconsistent. A 21-day feeding trial was conducted to evaluate the effect of chestnut tannin (CNT) extract on the enteric methane emissions (EME), [...] Read more.
Dietary tannin supplementation represents a potential strategy to modulate rumen fermentation and enhance lactation performance in dairy cows, though responses remain inconsistent. A 21-day feeding trial was conducted to evaluate the effect of chestnut tannin (CNT) extract on the enteric methane emissions (EME), blood metabolites, and milk production traits in mid-lactation dairy cows. Thirty-six Holstein cows were allocated to three homogeneous treatment groups: control (CNT0, 0 g/d CNT), CNT40 (40 g/d CNT), and CNT80 (80 g/d CNT). Measurements of EME, dry matter intake (DMI), milk yield (MY), and blood and milk parameters were carried out pre- and post-21-day supplementation period. Compared with the no-additive group, the CNT extract reduced methane production, methane yield, and methane intensity in CNT40 and CNT80 (p < 0.001). CNT40 and CNT80 cows exhibited lower blood urea nitrogen (p = 0.019 and p = 0.002) and elevated serum insulin (p = 0.003 and p < 0.001) and growth hormone concentrations (p = 0.046 and p = 0.034), coinciding with reduced aspartate aminotransferase (p = 0.016 and p = 0.045), and lactate dehydrogenase (p = 0.011 and p = 0.008) activities compared to control. However, CNT80 had higher circulating NEFA and BHBA than CNT0 (p = 0.003 and p = 0.004) and CNT40 (p = 0.035 and p = 0.019). The blood glucose, albumin, and total bilirubin concentrations were not affected. MY and fat- and protein-corrected milk (FPCM), MY/DMI, and FPCM/DMI were higher in both CNT40 (p = 0.004, p = 0.003, p = 0.014, p = 0.010) and CNT80 (p = 0.002, p = 0.003, p = 0.008, p = 0.013) cows compared with controls. Feeding CNT80 resulted in higher protein content (p = 0.015) but lower fat percentage in milk (p = 0.004) compared to CNT0. Milk urea nitrogen and somatic cell counts were significantly lower in both CNT40 (p < 0.001, p = 0.009) and CNT80 (p < 0.001 for both) compared to CNT0, while milk lactose did not differ between treatments. These findings demonstrate that chestnut tannin extract effectively mitigates EME while enhancing lactation performance in mid-lactation dairy cows. Full article
(This article belongs to the Special Issue Advances in Nutrition and Feeding Strategies for Dairy Cows)
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17 pages, 4077 KiB  
Article
The Impact of Sm Promoter on the Catalytic Performance of Ni/Al2O3-SiO2 in Methane Partial Oxidation for Enhanced H2 Production
by Salwa B. Alreshaidan, Rasha S. A. Alanazi, Omalsad H. Odhah, Ahmed A. Ibrahim, Fekri Abdulraqeb Ahmed Ali, Naif Alarifi, Khaled M. Banabdwin, Sivalingam Ramesh and Ahmed S. Al-Fatesh
Catalysts 2025, 15(8), 721; https://doi.org/10.3390/catal15080721 (registering DOI) - 29 Jul 2025
Viewed by 241
Abstract
This study investigates the effects of samarium (Sm) promotion on the catalytic activity of 5 weight percent Ni catalysts for partial oxidation of methane (POM)-based hydrogen production supported on a Si-Al mixed oxide (10SiO2+90Al2O3) system. Several 5% [...] Read more.
This study investigates the effects of samarium (Sm) promotion on the catalytic activity of 5 weight percent Ni catalysts for partial oxidation of methane (POM)-based hydrogen production supported on a Si-Al mixed oxide (10SiO2+90Al2O3) system. Several 5% Ni-based catalysts supported on silica–alumina was used to test the POM at 600 °C. Sm additions ranged from 0 to 2 wt.%. Impregnation was used to create these catalysts, which were then calcined at 500 °C and examined using BET, H2-TPR, XRD, FTIR, TEM, Raman spectroscopy, and TGA methods. Methane conversion (57.85%) and hydrogen yield (56.89%) were greatly increased with an ideal Sm loading of 1 wt.%, indicating increased catalytic activity and stability. According to catalytic tests, 1 wt.% Sm produced high CH4 conversion and H2 production, as well as enhanced stability and resistance to carbon deposition. Nitrogen physisorption demonstrated a progressive decrease in pore volume and surface area with the addition of Sm, while maintaining mesoporosity. At moderate Sm loadings, H2-TPR and XRD analyses showed changes in crystallinity and increased NiO reducibility. Sm incorporation into the support and its impact on the ordering of carbon species were indicated by FTIR and Raman spectra. The optimal conditions to maximize H2 yield were successfully identified through optimization of the best catalyst, and there was good agreement between the theoretical predictions (87.563%) and actual results (88.39%). This displays how successfully the optimization approach achieves the intended outcome. Overall, this study demonstrates that the performance and durability of Ni-based catalysts for generating syngas through POM are greatly enhanced by the addition of a moderate amount of Sm, particularly 1 wt.%. Full article
(This article belongs to the Section Industrial Catalysis)
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32 pages, 3694 KiB  
Article
Decoding Urban Traffic Pollution: Insights on Trends, Patterns, and Meteorological Influences for Policy Action in Bucharest, Romania
by Cristiana Tudor, Alexandra Horobet, Robert Sova, Lucian Belascu and Alma Pentescu
Atmosphere 2025, 16(8), 916; https://doi.org/10.3390/atmos16080916 - 29 Jul 2025
Viewed by 258
Abstract
Traffic-related pollutants remain a challenging global issue, with significant policy implications. Within the European Union, Romania has the highest yearly societal cost per capita due to air pollution, which kills 29,000 Romanians every year, whereas the health and economic costs are also significant. [...] Read more.
Traffic-related pollutants remain a challenging global issue, with significant policy implications. Within the European Union, Romania has the highest yearly societal cost per capita due to air pollution, which kills 29,000 Romanians every year, whereas the health and economic costs are also significant. In this context, municipal authorities in the country, particularly in high-density areas, should place a strong focus on mitigating air pollution. In particular, the capital city, Bucharest, ranks among the most congested cities in the world while registering the highest pollution index in Romania, with traffic pollution responsible for two-thirds of its air pollution. Consequently, studies that assess and model pollution trends are paramount to inform local policy-making processes and assist pollution-mitigation efforts. In this paper, a generalized additive modeling (GAM) framework is employed to model hourly concentrations of nitrogen dioxide (NO2), i.e., a relevant traffic-pollution proxy, at a busy urban traffic location in central Bucharest, Romania. All models are developed on a wide, fine-granularity dataset spanning January 2017–December 2022 and include extensive meteorological covariates. Model robustness is assured by switching between the generalized additive model (GAM) framework and the generalized additive mixed model (GAMM) framework when the residual autoregressive process needs to be specifically acknowledged. Results indicate that trend GAMs explain a large amount of the hourly variation in traffic pollution. Furthermore, meteorological factors contribute to increasing the models’ explanation power, with wind direction, relative humidity, and the interaction between wind speed and the atmospheric pressure emerging as important mitigators for NO2 concentrations in Bucharest. The results of this study can be valuable in assisting local authorities to take proactive measures for traffic pollution control in the capital city of Romania. Full article
(This article belongs to the Special Issue Sources Influencing Air Pollution and Their Control)
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16 pages, 4154 KiB  
Article
Comparative Proteomics Identified Proteins in Mung Bean Sprouts Under Different Concentrations of Urea
by Lifeng Wu, Chunquan Chen, Xiaoyu Zhou, Kailun Zheng, Xiaohan Liang and Jing Wei
Molecules 2025, 30(15), 3176; https://doi.org/10.3390/molecules30153176 - 29 Jul 2025
Viewed by 186
Abstract
Mung bean (Vigna radiate) sprouts are a popular choice among sprouted vegetables in Asia. Currently, the impact of nitrogen sources on the growth of mung bean sprouts remains poorly understood, and the underlying biological mechanisms responsible for the observed nonlinear growth [...] Read more.
Mung bean (Vigna radiate) sprouts are a popular choice among sprouted vegetables in Asia. Currently, the impact of nitrogen sources on the growth of mung bean sprouts remains poorly understood, and the underlying biological mechanisms responsible for the observed nonlinear growth patterns at different nitrogen levels have yet to be elucidated. In this research, in addition to conventional growth monitoring and quality evaluation, a comparative proteomics method was applied to investigate the molecular mechanisms of mung bean in response to 0, 0.025, 0.05, 0.075, and 0.1% urea concentrations. Our results indicated that mung bean sprout height and yield increased with rising urea concentrations but were suppressed beyond the L3 level (0.075% urea). Nitrate nitrogen and free amino acid content rose steadily with urea levels, whereas protein content, nitrate reductase activity, and nitrite levels followed a peak-then-decline trend, peaking at intermediate concentrations. Differential expression protein analysis was conducted on mung bean sprouts treated with different concentrations of urea, and more differentially expressed proteins participated in the L3 urea concentration. Analysis of common differential proteins among comparison groups showed that the mung bean sprouts enhanced their adaptability to urea stress environments by upregulating chlorophyll a-b binding protein and cationic amino acid transporter and downregulating the levels of glycosyltransferase, L-ascorbic acid, and cytochrome P450. The proteomic analysis uncovered the regulatory mechanisms governing these metabolic pathways, identifying 47 differentially expressed proteins (DEPs) involved in the biosynthesis of proteins, free amino acids, and nitrogen-related metabolites. Full article
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17 pages, 7508 KiB  
Article
Supramolecular Graphene Quantum Dots/Porphyrin Complex as Fluorescence Probe for Metal Ion Sensing
by Mariachiara Sarà, Andrea Romeo, Gabriele Lando, Maria Angela Castriciano, Roberto Zagami, Giovanni Neri and Luigi Monsù Scolaro
Int. J. Mol. Sci. 2025, 26(15), 7295; https://doi.org/10.3390/ijms26157295 - 28 Jul 2025
Viewed by 201
Abstract
Graphene quantum dots (GQDs) obtained by microwave-induced pyrolysis of glutamic acid and triethylenetetramine (trien) are fairly stable, emissive, water-soluble, and positively charged nano-systems able to interact with negatively charged meso-tetrakis(4-sulfonatophenyl) porphyrin (TPPS4). The stoichiometric control during the preparation affords a [...] Read more.
Graphene quantum dots (GQDs) obtained by microwave-induced pyrolysis of glutamic acid and triethylenetetramine (trien) are fairly stable, emissive, water-soluble, and positively charged nano-systems able to interact with negatively charged meso-tetrakis(4-sulfonatophenyl) porphyrin (TPPS4). The stoichiometric control during the preparation affords a supramolecular adduct, GQDs@TPPS4, that exhibits a double fluorescence emission from both the GQDs and the TPPS4 fluorophores. These supramolecular aggregates have an overall negative charge that is responsible for the condensation of cations in the nearby aqueous layer, and a three-fold acceleration of the metalation rates of Cu2+ ions has been observed with respect to the parent porphyrin. Addition of various metal ions leads to some changes in the UV/Vis spectra and has a different impact on the fluorescence emission of GQDs and TPPS4. The quenching efficiency of the TPPS4 emission follows the order Cu2+ > Hg2+ > Cd2+ > Pb2+ ~ Zn2+ ~ Co2+ ~ Ni2+ > Mn2+ ~ Cr3+ >> Mg2+ ~ Ca2+ ~ Ba2+, and it has been related to literature data and to the sitting-atop mechanism that large transition metal ions (e.g., Hg2+ and Cd2+) exhibit in their interaction with the macrocyclic nitrogen atoms of the porphyrin, inducing distortion and accelerating the insertion of smaller metal ions, such as Zn2+. For the most relevant metal ions, emission quenching of the porphyrin evidences a linear behavior in the micromolar range, with the emission of the GQDs being moderately affected through a filter effect. Deliberate pollution of the samples with Zn2+ reveals the ability of the GQDs@TPPS4 adduct to detect sensitively Cu2+, Hg2+, and Cd2+ ions. Full article
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12 pages, 1421 KiB  
Article
Enzymatic Stoichiometry and Driving Factors Under Different Land-Use Types in the Qinghai–Tibet Plateau Region
by Yonggang Zhu, Feng Xiong, Derong Wu, Baoguo Zhao, Wenwu Wang, Biao Bi, Yihang Liu, Meng Liang and Sha Xue
Land 2025, 14(8), 1550; https://doi.org/10.3390/land14081550 - 28 Jul 2025
Viewed by 109
Abstract
Eco-enzymatic stoichiometry provides a basis for understanding soil ecosystem functions, with implications for land management and ecological protection. Long-term climatic factors and human interferences have caused significant land-use transformations in the Qinghai–Tibet Plateau region, affecting various ecological functions, such as soil nutrient cycling [...] Read more.
Eco-enzymatic stoichiometry provides a basis for understanding soil ecosystem functions, with implications for land management and ecological protection. Long-term climatic factors and human interferences have caused significant land-use transformations in the Qinghai–Tibet Plateau region, affecting various ecological functions, such as soil nutrient cycling and chemical element balance. It is currently unclear how large-scale land-use conversion affects soil ecological stoichiometry. In this study, 763 soil samples were collected across three land-use types: farmland, grassland, and forest land. In addition, changes in soil physicochemical properties and enzyme activity and stoichiometry were determined. The soil available phosphorus (SAP) and total phosphorus (TP) concentrations were the highest in farmland soil. Bulk density, pH, SAP, TP, and NO3-N were lower in forest soil, whereas NH4+-N, available nitrogen, soil organic carbon (SOC), available potassium, and the soil nutrient ratio increased. Land-use conversion promoted soil β-1,4-glucosidase, N-acetyl-β-glucosaminidase, and alkaline phosphatase activities, mostly in forest soil. The eco-enzymatic C:N ratio was higher in farmland soils but grassland soils had a higher enzymatic C:P and N:P. Soil microorganisms were limited by P nutrients in all land-use patterns. C limitation was the highest in farmland soil. The redundancy analysis indicated that the ecological stoichiometry in farmland was influenced by TN, whereas grass and forest soils were influenced by SOC. Overall, the conversion of cropland or grassland to complex land-use types can effectively enhance soil nutrients, enzyme activities, and ecosystem functions, providing valuable insights for ecological restoration and sustainable land management in alpine regions. Full article
(This article belongs to the Section Land Use, Impact Assessment and Sustainability)
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19 pages, 4654 KiB  
Article
Optimizing Nitrogen Fertilizer Rate and Investigating Mechanism Driving Grain Yield Increase for Rice in the Middle Reaches of the Yangtze River
by Tianxiang Xu, Hailin Zhang, Jie Gong, Ling Wang, Yongsheng Wang, Weiwen Qiu, Muxing Liu, Shenglong Li, Yuanhang Fei, Qi Li, Xin Ni, Jun Yi and Chuanqin Huang
Plants 2025, 14(15), 2326; https://doi.org/10.3390/plants14152326 - 27 Jul 2025
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Abstract
Investigating the factors influencing rice grain yield (GY) is critical for optimizing nitrogen (N) management and enhancing resource use efficiency in rice cultivation. However, few studies have comprehensively investigated the factors affecting rice GY, considering an entire influence chain encompassing rice N uptake, [...] Read more.
Investigating the factors influencing rice grain yield (GY) is critical for optimizing nitrogen (N) management and enhancing resource use efficiency in rice cultivation. However, few studies have comprehensively investigated the factors affecting rice GY, considering an entire influence chain encompassing rice N uptake, growth indicators, and GY components. In this study, field experiment with six different N fertilizer rates (0, 60, 120, 180, 225, and 300 kg N ha−1, i.e., N0, N60, N120, N180, N225, and N300) was conducted in the Jianghan Plain in the Middle Reaches of the Yangtze River, China, to comprehensively elucidate the factors influencing rice GY from aspects of rice N uptake, growth indicators, and GY components and determine the optimal N fertilizer rate. The results showed that rice GY and N uptake initially increased and then either stabilized or declined with higher N fertilizer rate, while apparent N loss escalated with increased N fertilizer rate. The application of N fertilizer significantly promoted the increase in straw N uptake, which was significantly positively correlated with growth indicators (p < 0.05). Among all GY components, panicle number per hill was the most significant positive factor influencing rice GY, and it was significantly positively correlated with all rice growth indicators (p < 0.05). In addition, N180 was the optimal N fertilizer rate, ensuring more than 95% of maximum GY and reducing N loss by 74% and 39% compared to N300, respectively. Meanwhile, the average N balance for N180 remained below 60 kg N ha−1. In conclusion, optimizing the N fertilizer application in paddy fields can effectively maintain stable rice GY and minimize environmental pollution. Full article
(This article belongs to the Special Issue Water and Nitrogen Management in the Soil–Crop System (3rd Edition))
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26 pages, 10667 KiB  
Article
Influence of Nitrogen and Hydrogen Addition on Composition, Morphology, Adhesion, and Wear Resistance of Amorphous Carbon Coatings Produced by RFCVD Method on Surface-Hardened Ultra-Fine Grained Bainitic 30HGSNA Steel
by Karol Wunsch, Tomasz Borowski, Emilia Skołek, Agata Roguska, Rafał Chodun, Michał Urbańczyk, Krzysztof Kulikowski, Maciej Spychalski, Andrzej Wieczorek and Jerzy Robert Sobiecki
Coatings 2025, 15(8), 877; https://doi.org/10.3390/coatings15080877 - 26 Jul 2025
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Abstract
Ultra-fine-grained bainitic (UFGB) steels offer excellent mechanical properties, which can be further improved by applying diamond-like carbon (DLC) coatings. However, poor adhesion between the coating and substrate remains a key limitation. Since the steel’s microstructure degrades at high temperatures, enhancing adhesion without heating [...] Read more.
Ultra-fine-grained bainitic (UFGB) steels offer excellent mechanical properties, which can be further improved by applying diamond-like carbon (DLC) coatings. However, poor adhesion between the coating and substrate remains a key limitation. Since the steel’s microstructure degrades at high temperatures, enhancing adhesion without heating the substrate is essential. This study investigates surface hardening combined with simultaneous nitrogen and hydrogen doping during the Radio Frequency Chemical Vapor Deposition (RFCVD) process to improve coating performance. Varying gas compositions were tested to assess their effects on coating properties. Nitrogen incorporation decreased hardness from 12 GPa to 9 GPa but improved adhesion, while hydrogen limited damage after coating failure. Optimizing the gas mixture led to enhanced adhesion and wear resistance. Raman and X-ray photoelectron spectroscopy (XPS) analyses confirmed that the optimized coatings had the highest sp3 bond content and elevated nitrogen levels. While both hardness and adhesion contributed to wear resistance, no direct link to coating thickness was found. Overall, co-doping with nitrogen and hydrogen is an effective approach to improve adhesion and wear resistance without requiring high processing temperatures or complex equipment. Full article
(This article belongs to the Special Issue Recent Advances in Surface Functionalisation, 2nd Edition)
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20 pages, 3076 KiB  
Article
Options and Scenarios for the Prishtina Wastewater Treatment Plant-Design Efficiency
by Sokol Xhafa, Tamás Koncsos and Miklós Patziger
Water 2025, 17(15), 2220; https://doi.org/10.3390/w17152220 - 25 Jul 2025
Viewed by 275
Abstract
This research assesses the design efficiency of the future centralized wastewater treatment plant (WWTP) in Prishtina, which also takes into consideration rapidly expanding suburban areas, such as Fushë Kosova, Obiliq, and Graçanica. Using a combination of both ATV-DVWK-A 131E deterministic calculations and dynamic [...] Read more.
This research assesses the design efficiency of the future centralized wastewater treatment plant (WWTP) in Prishtina, which also takes into consideration rapidly expanding suburban areas, such as Fushë Kosova, Obiliq, and Graçanica. Using a combination of both ATV-DVWK-A 131E deterministic calculations and dynamic simulation with IWASP, this study focuses on the planned configurations for the future Prishtina wastewater treatment plant (WWTP) to evaluate design efficiency alongside operational feasibility. The primary goal was to determine if meeting projected loads for the year 2040 would be possible with compliance requirements for a single-stage CAS system. Simulation data suggest that reliable nitrogen removal would not be possible with a sole CAS stage (aerobic), particularly considering seasonal and peak load dynamics. Alternatively, an optimized three-reactor CAS model, including one anoxic pre-denitrification zone coupled with two alternating aerobic zones, achieved an average total nitrogen (TN) removal efficiency of about 85%, maintaining effluent TN below 10 mg/L. Additional advantages saw COD being removed at rates between 90 and 92%, along with MLSS levels stabilizing around 3500 mg/L. The flexibly scalable design also provides adaptive operation features, including expanded tertiary nutrient removal in phase II. In scenario two’s site comparative analysis, Lismir’s centralized WWTP emerges as the most economically and technically rational option due to the enhanced reactor layout optimization. These findings confirm that enhanced configurations, validated through both static and dynamic analyses, are essential for long-term treatment efficiency and regulatory compliance. Full article
(This article belongs to the Special Issue Urban Sewer Systems: Monitoring, Modeling and Management)
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