Decrease In Water Content Research Articles

Dynamic reaction of slag-based geopolymer with brick powder: insights from acoustic emission, heat flow, and relaxation characteristics

Fractal dimension, heat, and NMR relaxation characterizations were employed to monitor the dynamic geopolymerization process of slag-based geopolymer (SBG) with brick powder (BP) in this research. Introducing 30% BP to SBG resulted in a delay of 6minutes in the occurrence of polymerization peak, with a 24.12% decrease in heat peak value. Furthermore, during the rapid polymerization phase, the time of the gel formation in SBG containing 30% BP was reduced by 34.18%, accompanied by a 20.91% decrease in gel water content. The sequence of AE parameters associated with early-age geopolymerization reaction has good fractal characteristics, with fitting coefficient greater than 0.95. Importantly, the heat flow curve, water evolution, and corresponding fractal dimension curves have good correspondence at 0-3h. Especially, the dissolution peak and polymerization peak of the heat flow curve basically coincide with the fractal dimension curve. The fractal dimension not only serves as an effective indicator for evaluating the geopolymerization process but also compensates for the limitations of calorimetry in characterizing reaction processes with relatively small particle migration and local heat release.

Warming Mitigates Ozone Damage to Wheat Photosynthesis in a FACE Experiment.

Individual effects of elevated ozone (O3) and warming on wheat (Triticum aestivum L.) are well documented, their combined effects remain poorly understood. In the present study, we investigated the combined impacts of elevated O3 (1.5× ambient O3) and rising canopy temperature (+2°C) on the photosynthesis of wheat leaves in an open-air field experiment. We found that O3-induced oxidative stress reduced the biochemical capacity and inhibited leaf photosynthesis at the end of the grain-filling stage. Night-time warming (NW) increased leaf photosynthesis during the vegetative stage, but whole-day warming (WW) did not. Both WW and NW accelerated wheat development and decreased photosynthesis at the end of the reproductive stage. Neither elevated O3 nor warming stimulated antioxidant enzymes. Significant interaction between O3 and WW indicated that WW mitigated the adverse effect of O3 on leaf photosynthesis. Compared to NW, WW significantly increased daytime canopy temperature and canopy-to-air vapour pressure deficit across O3 treatments. Decreases in leaf water content and increases in grain oxygen isotope discrimination under warming suggested a link of WW-induced protection against O3 stress in photosynthesis with declines in stomatal O3 uptake rather than increases in the antioxidant capacity. Our results indicate the need to consider the warming-induced mitigation of O3 stress on leaf photosynthesis when predicting the effects of elevated O3 on crop growth under warmer climate in the future.

Multifunctional Biocomposite Materials from Chlorella vulgaris Microalgae.

Extrusion 3D-printing of biopolymers and natural fiber-based biocomposites enables the fabrication of complex structures, ranging from implants' scaffolds to eco-friendly structural materials. However, conventional polymer extrusion requires high energy consumption to reduce viscosity, and natural fiber reinforcement often requires harsh chemical treatments to improve adhesion. We address these challenges by introducing a sustainable framework to fabricate natural biocomposites using Chlorella vulgaris microalgae as the matrix. Through bioink optimization and process refinement, we produced lightweight, multifunctional materials with hierarchical architectures. Infrared spectroscopy analysis reveals that hydrogen bonding plays a critical role in the binding and reinforcement of Chlorella cells by hydroxyethyl cellulose (HEC). As water content decreases, the hydrogen bonding network evolves from water-mediated interactions to direct hydrogen bonds between HEC and Chlorella, enhancing the mechanical properties. A controlled dehydration process maintains continuous microalgae morphology, preventing cracking. The resulting biocomposites exhibit a bending stiffness of 1.6 GPa and isotropic heat transfer and thermal conductivity of 0.10 W/mK at room temperature, demonstrating effective thermal insulation. These characteristics make Chlorella biocomposites promising candidates for applications requiring both structural performance and thermal insulation, offering a sustainable alternative to conventional materials in response to growing environmental demands.

Role of synthesis temperature in the formation of ZnO nanoparticles via the Sol-Gel process

This study examines the synthesis of ZnO powder via the sol–gel method at temperatures of 25 °C and 60 °C. Characterization was conducted using standard techniques to investigate how these temperature conditions influence the physicochemical properties of the resulting material. XRD analysis confirmed high crystallinity with a pure hexagonal wurtzite structure, with average crystallite sizes of approximately 20 nm at 25 °C and 38 nm at 60 °C. Both SEM and TEM techniques established needle-like nanorods at 25 °C and nanoflower-like structures at 60 °C. Analyzing the high-resolution XPS spectra of the Zn2p and O1s photoelectron lines revealed a predominant Zn(II) state, with the contribution of ZnO increasing from 14.6 at.% to 41.6 at.% at higher temperatures. This change was accompanied by a decrease in defective oxygen and water content. Furthermore, DSC analysis revealed significant differences in thermal properties of ZnO powders synthesized at 25 °C and 60 °C, with distinct endothermic peaks around 120 °C corresponding to the evaporation of the solvent used in the synthesis process. The energy required for phase transitions was notably higher for the 25 °C synthesis, indicating greater thermal stability and energy demands compared to the 60 °C synthesis.

Effect of tea polyphenols on the quality of frozen cooked noodles

AbstractBackground and ObjectivesThe growing consumer demand for natural, healthy, and convenient food options has led to the rising popularity of frozen cooked noodles (FCN). Tea polyphenols (TPs), known for their diverse biological activities, are increasingly being utilized as a natural food additive in research and development. Therefore, this study aims to investigate the effects of TPs on the thermal and pasting properties of wheat flour as well as their influence on the quality of FCN.FindingsThe results from differential scanning calorimeter and RVA analyses showed that TPs did not significantly affect the thermal and pasting properties of wheat flour. However, the addition of low‐dose TPs (<1.5%) improved the quality of FCN during storage. Texture and tensile analyses demonstrated an enhancement in hardness, chewiness, resistance, and an increase in resistant starch content in the noodles. Low‐field nuclear magnetic resonance findings revealed an increase in the proportion of strongly bound water, accompanied by a decrease in free water content. Scanning electron microscopy observations illustrated a well‐developed gluten network structure. In contrast, the incorporation of 1.5% TPs adversely affected the quality of FCN.ConclusionsThe appropriate integration of TPs plays a significant role in alleviating the quality degradation of FCN during storage.Significance and NoveltyThis study provides a theoretical basis for the development of polyphenol‐enriched flour products and functional foods.

Characterization and prediction of hydraulic properties of traffic-compacted forest soils based on soil information and traffic treatments

Key messageThe hydraulic properties of compacted and rutted soils were evaluated through in-situ infiltration experiments and predicted based on soil texture class and traffic treatments. A significant decrease in saturated soil water content and soil hydraulic conductivity at saturation was observed. The resulting soil hydraulic parameters, when integrated into a soil water transfer model, effectively simulated water dynamics in these impacted forest soils, providing a crucial first step toward developing decision support tools for real-time trafficability. This approach can assist forest managers in minimizing the extent of soil compaction.ContextTo overcome trafficability issues of forest soils induced by heavy logging machinery, planning support tools are needed to determine suitable soil moisture conditions for traffic.AimsThis study aimed to identify the soil properties that differ significantly between undisturbed and compacted soils and to provide several estimation tools to predict the hydraulic properties of compacted soils beneath the skid trails.MethodsFour hundred seventeen water infiltration tests were conducted on 19 forest sites, mostly in North-eastern France, and analysed with the BEST method to estimate the hydraulic properties of the skid trails and undisturbed soils. The hydraulic properties of the skid trails were predicted thanks to linear mixed effect models using a bulk treatment effect, a site effect, or a skid trail degradation score. The predicted hydraulic properties were tested using a water flow model to assess their relevance regarding the prediction of water dynamics in skid trails.ResultsThe compaction effect was only significant for the logarithm of the hydraulic conductivity at saturation (log10(Ksat)) and the soil water content at saturation (θsat). For the skid trails, θsat was reduced by - 0.02 and − 0.11 m3m−3 in the 0 − 10 cm and 15 − 25 cm layers respectively, compared to undisturbed topsoil (0 − 10 cm). log10(Ksat) was reduced by − 0.38 and − 0.85 for skid trails in the 0 − 10 and 15 − 25 cm soil layers respectively, compared to undisturbed topsoil. The use of a pedotransfer function, in replacement of water infiltration tests, and their combination with the same correction coefficients proved to efficiently simulate the difference in water dynamics between skid trails and undisturbed forest soils.ConclusionEstimation of soil hydraulic properties based on in situ water infiltration experiments proved efficient to simulate water dynamics in compacted and rutted forest soils. Yet, further studies are needed to identify the most adapted pedotransfer function to forest soils and to test the generalisation of our findings in different conditions, especially deeply rutted soils (rut depths > 12 cm).

Dynamic characteristics of soil pore structure and water-heat variations during freeze-thaw process

Freeze-thaw processes in cold regions alter soil pore structure and properties, leading to engineering geological issues. Soil pores are crucial, but research on their changes and freeze-thaw impacts is limited. This study used MRI-Cryogenic Soil Moisture Analyzer (MRI-CSMA) to explore pore structure, water, and temperature changes in saturated loess during freeze-thaw, and Scanning Electron Microscopy (SEM) to compare changes before and after. The results indicate that during the freezing process, the temperature in the frozen zone of the soil sample exhibited a staged change characterized by rapid cooling, transitional cooling, and stabilization at low temperatures, while the temperature decrease in the unfrozen zone showed no significant stages. Freeze-thaw action significantly affected the macropores and mesopores in the frozen zone, with an average increase of 15 % in macropores, a decrease of 16 % in mesopores, and minimal change in micropores (about a 1 % increase). In the unfrozen zone, there was a slight increase in micropores and mesopores (2 % and 3 %, respectively), and a 4 % decrease in macropores. Furthermore, during the freezing process, macropores in the unfrozen zone gradually decreased, while mesopores and micropores increased, leading to soil structure densification and promoting water migration towards the freezing front. This resulted in an initial increase followed by a decrease in water content near the freezing front during the early stages of freezing, confirming the view that pore structure compression drives water migration in the early stages of soil freezing. This study provides important insights for addressing engineering geological issues in cold regions under freeze-thaw conditions.

The Use of Machine Learning to Assess the Impact of the Ozonation Process on Selected Mechanical Properties of Japanese Quince Fruits

In this study, selected mechanical properties of fruits of six varieties of Japanese quince (Chaenomeles japonica) were investigated. The influence of their storage time and the applied ozone at a concentration of 10 ppm for 15 and 30 min on water content, skin and flesh puncture force, deformation to puncture and puncture energy was determined. After 60 days of storage, the fruits of the tested varieties showed a decrease in the average water content from 97.94% to 94.39%. No influence of the ozonation process on the change in water content in the fruits was noted. The tests showed a significant influence of ozonation and storage time on the increase in the punch puncture force of the skin and flesh, deformation and puncture energy of the fruits. In order to establish the relationship between storage conditions for various varieties and selected mechanical parameters, a novel machine learning method was employed. The best model accuracy was achieved for energy, with a MAPE of 10% and a coefficient of correlation (R) of 0.92 for the test data set. The best metamodels for force and deformation produced slightly higher MAPE (12% and 17%, respectively) and R of 0.72 and 0.88.

Foliar Methyl Jasmonate Application Activates Antioxidant Mechanisms to Counteract Water Deficits and Aluminum Stress in Vaccinium corymbosum L.

Due to climate change, water deficits (WDs) and aluminum (Al) toxicity are increasing, affecting plants, especially crops such as blueberries (Vaccinium corymbosum L.). The application of methyl jasmonate (MeJA) could mitigate these effects. This work aimed to evaluate the effective MeJA dose to overcome oxidative stress provoked by combined WD+Al stress in blueberries. Plants of Al-sensitive (Star) and Al-resistant (Legacy) cultivars were exposed to control (Al at 65 mg/Kg, 80% field capacity), WD+Al (50% field capacity; Al at 1665 mg/Kg), and WD+Al treatment with different foliar MeJA doses (10, 50, and 100 μM) during 7 and 21 days. Data revealed that plants exposed to WD+Al and treated with 50 µM MeJA reduced Al up to 3.2-fold in roots and 2.7-fold in leaves and improved water potential (Ψw) up to 2.5-fold. The sensitive cultivar decreased the relative growth rate under WD+Al, increasing by 1.9-fold with 50 µM MeJA. Under WD+Al stress, all MeJA doses mitigated the decrease in relative water content in Al-resistant cultivars, restoring values like control plants. In the sensitive cultivar, 50 µM MeJA increased photosynthesis (1.5-fold) and stomatal conductance (1.4-fold), without changes in transpiration. Lipid peroxidation decreased (1.2-fold) and increased antioxidant activity (1.8-fold), total phenols (1.6-fold), and superoxide dismutase activity (3.3-fold) under WD+Al and 50 µM-MeJA. It was concluded that the most effective dose to alleviate the WD+Al stress was 50 µM MeJA due to the activation of antioxidants in blueberry plants. Therefore, the MeJA application could be a potential strategy for enhancing the resilience of V. corynbosum exposed to WD+Al stress.

Coordination, hydration, and diffusion of vanadyl cations in negatively charged polymer membranes

Charged polymer membranes that selectively transport ions are crucial for advancing electrochemical technologies for water purification, resource recovery, and energy generation/storage. Recent studies suggest that the ion selectivity trends of such membranes are due to ion dehydration at the membrane/solution interface, where ions that require less energy to shed their hydration can partition more favorably into the membrane. However, direct evidence of ion dehydration in polymer membranes at relevant conditions is scarce, with claims based primarily on correlations between ion hydration energies and membrane transport properties. The objective of this study was to investigate the electronic environment, local coordination, and hydration of vanadyl counter-ion in negatively charged membranes with broadly varying water content via x-ray absorption spectroscopy. The results highlight that vanadyl counter-ions maintain similar oxidation state, electronic state, and coordination number in the membranes as in aqueous solutions of vanadyl sulfate and that vanadyl dehydration is unlikely in these membranes. However, as the membrane water content decreases, the vanadyl diffusion coefficient decreases and the activation energy of diffusion increases. We attribute these significant changes in membrane transport properties to increased Coulombic interactions between vanadyl and the fixed charge groups, resulting from a decreased dielectric constant of the membrane, rather than to ion dehydration at the membrane/solution interface. This study represents significant progress in understanding the mechanisms that govern ion transport in charged polymer membranes over a broad range of water content, highlighting the critical role of Coulombic interactions between the fixed charges and mobile ions.

Transport behavior of Polymeric Methyl Methacrylate nanoplastics in saturated and unsaturated porous media: Combined influence of electrolyte and organic acids

The migration behavior of Polymeric Methyl Methacrylate (PMMA) nanoplastics in saturated porous media and unsaturated porous media is investigated under conditions of electrolytes in combination with organic acids. In the saturated porous media, the mass recovery rate of PMMA decreases with ionic strength. The inhibition effect of Ca2+ on PMMA transport is stronger than that of Na+. Under the conditions of the coexistence of electrolytes with humic acid (HA), increasing the concentration of HA does not consistently enhance PMMA migration in porous media. However, citric acid (CA) exerts solely an inhibitory effect on PMMA transport. The orthogonal analysis suggests that Ca2+ concentration is the major factor affecting PMMA transport. Extended Darjaguin-Landau-Verwe-Overbeek (XDLVO) interaction energy considering the heterogeneity of HA adsorption on PMMA is calculated to quantify the interactions of PMMA-PMMA and PMMA-quartz sand under different physiochemical conditions. In unsaturated porous media, gravity leads to the creation of dominant channels, and the shear force of water flow in porous media leads to the rapid passage of PMMA through the dominant channels. However, as the water content decreases, the recovery rate of PMMA decreases from 0.99 to 0.71. Significantly, the capillary energy of a colloid retained in a thin film or at the air-water-solid (AWS) interface is several orders of magnitude larger than the XDLVO interaction energy. Findings obtained by this study may improve the current understanding of the environmental fate of nanoplastics in subsurface environments and can provide scientific methods to assess the associated risk of nanoplastics.

Impact of cocoa variety on merchant quality and physicochemical characteristics of raw cocoa beans and roasted cocoa mass

Cocoa, a widely cultivated crop in tropical countries, is a crucial raw material in the food industry, particularly in chocolate production. Its quality is influenced by various factors, including variety, cultivation practices, fermentation, and drying. The aim of this work was to investigate the impact of the cocoa variety on the merchant quality and the physicochemical properties of raw cocoa beans and roasted cocoa mass produced in the urban commune of Pokola (Republic of the Congo) . Cocoa pods were sorted into three varieties (Criollo, Forastero, and Trinitario) according to the physical identification criteria given in the literature. Cocoa samples were prepared according to the same process: each variety was separated into three 50-kg samples placed in cubic crates with 40 cm edges covered with banana leaves for 6 days of fermentation, then sun-dried at 28–32 °C for 7 days, leading to dried cocoa beans. Roasted cocoa masses were obtained by roasting at 140 °C followed by grinding. Merchant quality analyses were carried out on raw cocoa beans and physicochemical analyses were performed on raw cocoa beans and roasted cocoa masses. Cocoa variety had the greatest impact on graining, Villtrop swelling index, proportion of brown beans, pH, total acidity, and protein content. The beans of all cocoa varieties were of intermediate merchant quality (grade II). Roasting resulted in an increase in pH and total carbohydrate content, and a decrease in water content, total acidity, protein content, and colorimetric parameters. Overall, the cocoa variety had a weaker influence on the quality and physicochemical properties of raw and roasted cocoa than roasting.

Soil behavior near the PVD filter and interpretation of clogging during vacuum preloading

Clogging near the prefabricated vertical drain filter during vacuum preloading reduces the efficiency of ground treatment, and existing research has yet to agree on the cause. This study conducted a small model test to comprehensively examine the soil's water content and particle size distribution at different distances from the filter and tailwater for different preloading durations. The results showed that the particle size distribution of the soil at different selected points exhibited a slightly irregular difference. This indicates that no measurable migration of particles occurs, which was further confirmed by the particle size distribution of the soil after the one-dimensional consolidation test. The application of vacuum pressure did not significantly change the soil particle composition and, thus, its compressibility and permeability properties. The particle size distribution of tailwater revealed that a small number of fine particles with a mean size of 3–4 μm rapidly discharged with tailwater during the initial stage of vacuum preloading, which was much less than the mean size of the slurry and pore size of the filter. The decrease in water content and permeability indicates non-uniform consolidation, and the increase in the permeability coefficient ratio suggests the formation and development of the clogging zone.

Analysis of Corn Drying Rack Position on Tray Type Dryer on Drying Rate

This research aims to determine the drying characteristics of corn kernels using a tray-type dryer, including the moisture content of the corn kernels over time, the mass of the tested corn kernels over time and the drying rate over time. This research uses the experimental method. The drying process uses an incoming drying hot air temperature of 65ºC with an incoming hot drying air speed of 2 m/s, repeated three times until a water content of 14 ± 0.5% is reached. The dryer in this study used four stacking shelves counting from the bottom, which were filled with 500 grams per shelf. This research shows that the further the shelf is positioned from the incoming hot drying air, the lower the drying rate. Vice versa, the closer the drying Shelf is to the incoming hot air, the greater the drying rate. The average decrease in corn kernel mass was 0.95% for shelf 1, 0.93% for shelf 2, 0.90% for shelf 3 and 0.88% for shelf 4 during a drying period of 3.5 hours. The average decrease in water content was 4.4% for shelf 1, 4.29% for shelf 2, 4.15% for shelf 3 and 4% for shelf 4 during a drying period of 3.5 hours. The further the position of the shelf from the hot air dryer, the less air content contained in the material on the shelf can be absorbed by the hot air dryer and vice versa. The average drying rate was 16.8% for shelf 1, 15% for shelf 2, 13.6% for shelf 3 and 12.8% for shelf 4 during a drying period of 3.5 hours at a drying hot air temperature of 65oC with a drying air speed of 2 m/s. The research data analysis results showed that the hot air dryer should not be passed from below but rather from the side. This affects the drying process in the dryer and makes it evener.

The Influence of Water Deficit on Dehydrin Content in Callus Culture Cells of Scots Pine

Under a water deficit, the protective proteins known as dehydrins (DHNs) prevent nonspecific interactions in protein and membrane structures and their damage, in addition to playing an antioxidant role. The DHNs of a widespread xerophytic species Scots pine (Pinus sylvestris L.) have been poorly studied, and their role in resistance to water deficits has not been revealed. In this paper, we have expanded the list of DHNs that accumulate in the cells of Scots pine under the conditions of water deficits and revealed their relationship with the effects of water deficits. In this investigation, callus cultures of branches and buds of Scots pine were used. A weak water deficit was created by adding polyethylene glycol to the culture medium. Under the conditions of a water deficit, the activity of catalase and peroxidase enzymes increased in the callus cultures. A moderate decrease in the total water content was correlated with a decrease in the growth rate of the callus cultures, as well as with an increase in the activity of lipid peroxidation. The accumulation of Mr 72, 38, and 27 kDa DHNs occurred in the callus cultures of buds, and the accumulation of Mr 72 and 27 kDa DHNs positively correlated with the lipid peroxidation activity. An increase in the content of DHNs was observed in cultures that differed in origin, growth indicators, and biochemical parameters, indicating the universality of this reaction. Thus, previously undescribed DHNs were identified, the accumulation of which is caused by water deficiency and is associated with manifestations of oxidative stress in the kidney cells of Scots pine.

Vegetation Restoration Increases the Drought Risk on the Loess Plateau.

The extensive implementation of the 'Grain for Green' project over the Loess Plateau has improved environmental quality. However, it has resulted in a greater consumption of soil water, and its overall hydrological effects remain highly controversial. Our study utilized a coupled land-atmosphere model to evaluate the effects of vegetation changes resulting from revegetation or reclamation on the hydrology of the Loess Plateau. Revegetation was found to stimulate an increase in precipitation, evapotranspiration, and atmospheric water content. However, the increase in precipitation was insufficient to compensate for soil water loss driven by intensified evapotranspiration, resulting in a decrease in both runoff and soil water content. In contrast to revegetation, reclamation would reduce precipitation, although the reduction was less than the decrease in evapotranspiration. This could lead to an increase in both runoff and soil water content. The results provide an important scientific basis for the hydrological effects of vegetation changes on the Loess Plateau, which is particularly important for guiding current and future revegetation activities toward sustainable ecosystem development and water resources management.

Total Polyphenol Content and Antioxidant Activity of Leaves and Fine Roots as Indicators of Drought Resistance in the Native Quercus robur and Alien Quercus rubra

Research Highlights: Environmental abiotic stressors generate secondary stresses in plants, such as osmotic and oxidative stresses, which negatively influence their normal growth, development, and metabolism. Research about other non-enzymatic components with antioxidant capacity has recently focused on polyphenols. However, their role as indicators of drought and shade tolerance in woody species leaves and roots has been poorly explored or was limited to leaves only. Background and Objectives: Under a scenario of increasing drought, understanding the seedling responses in terms of total polyphenols and their antioxidant activity, in particular at the fine root system level, may help to elucidate the native–alien species interaction. Materials and Methods: At the beginning of July, 5-month-old native Quercus robur and alien Quercus rubra seedlings were transferred indoors to the growth chamber and subjected to progressive soil drying for 21 days. Results: The decrease in soil water content was more pronounced for Q. robur (9%) than for Q. rubra (34% of field capacity). Leaf water potential significantly decreased over time in Q. robur but did not differ from the control in Q. rubra. The total polyphenol concentration in Q. robur was markedly lower in the leaves and significantly higher in the fine roots than in Q. rubra. For the leaves, both species showed markedly higher values if well-watered, and the values significantly decreased in response to drought only in Q. rubra. In contrast, the fine root values for both species were markedly higher if droughted and decreased significantly in time only in Q. robur. Differently from the polyphenol concentration, the antioxidant capacity of Q. rubra was always higher in both the leaves and fine roots. Conclusions: The higher antioxidant activity of the alien species Q. rubra revealed by this work, combined with its isohydric behaviour, could further shed some light on our understanding of its competitive performance at the seedling stage against the native Q. robur.

Construction of a stable YOLOv8 classification model for apple bruising detection based on physicochemical property analysis and structured-illumination reflectance imaging

Effective and accurate detection of bruises at all stages has always been a challenge in non-destructive grading of apples. In this study, the visible structured-illumination reflectance imaging (SIRI) combing with deep learning method was proposed to identify bruised ‘Fuji’ apples at four different time stages (0, 6, 12 and 24 h). The macroscopic/microscopic structures and physicochemical properties of bruised tissue were measured and analyzed to determine the relationship between bruising time and these properties, as well as how they affect the accuracy of bruising detection. Results indicated that classification accuracy increased with the decrease of water and total phenolic content of the bruised tissue, as well as with the increase of color browning and bruised area. The YOLOv8 model achieved the highest detection accuracy (99.5 %) and stability. This research enhances understanding of apple bruise optics and aids in developing advanced nondestructive testing techniques.

Consequences of intense drought on CO2 and CH4 fluxes of the reed ecosystem at Lake Neusiedl

Reed (Phragmites australis) dominated wetlands are commonly known as strong carbon (C) sinks due to the high productivity of the reed plant and C fixation in the wetland soil. However, little is known about the effects of drought on reed-dominated wetlands and the possibility of Pannonian reed ecosystems being a source of greenhouse gases (GHG). The drought at Lake Neusiedl had a particular impact on the water level, but also had consequences for the reed belt. Therefore, we investigated the drought-influenced C fluxes and their drivers in the reed ecosystem of this subsaline lake over a period of 4.5 years (mid-2018 to 2022). We applied eddy covariance technique to continuously quantify the vertical turbulent GHG exchange between reed belt & atmosphere and used vegetation indices to account for reed growth. Methane emissions decreased by 76% from 9.2 g CH4-C m-2a-1 (2019) to 2.2 g CH4-C m-2 a-1 (2022), which can be explained by the falling water level, the associated drying out of the reed belt and its consequences. Carbon dioxide emissions initially decreased by 85% from 181 g CO2-C m-2 a-1 (2019) to 27 g CO2-C m-2 a-1 (2021), but then increased to twice the 2019 level in 2022 (391 g CO2-C m-2 a-1). Due to the drying reed belt, the reed initially grew into formerly water-covered areas within the reed belt, especially in 2021, leading to higher photosynthesis through 2021. This development stopped and even reversed in 2022 as a consequence of the sharp decrease in sediment water content from about 65 to 32 Vol-% in mid-2022. Overall, drought led to a decoupling of the reed ecosystem from the open lake area and developed the wetland into a strong C source.

Exogenous Melatonin Alleviates Osmotic Stress by Enhancing Antioxidant Metabolism, Photosynthetic Maintenance, and Hormone Homeostasis in Forage Oat (Avena sativa) Seedlings

Melatonin (MT) is a multifunctional hormone that enhances crop resilience against various abiotic stresses. However, its regulatory mechanism of osmotic tolerance in forage oats (Avena sativa) plants under water-limited scenarios is still unclear. This study aimed to delineate the impact of MT pretreatment on the morphological, physiological, and biochemical functions of oat seedlings under osmotic stress. Our findings demonstrated that exogenous treatment of MT noticeably elevated leaf area while decreasing the root/shoot ratio of oat seedlings subjected to osmotic stress. Osmotic-induced 38.22% or 48.37% decrease in relative water content could be significantly alleviated by MT pretreatment on day 7 or day 14, respectively. MT treatment also significantly mitigated osmotic-induced decreases in photosynthetic parameters including net photosynthetic rate, stomatic conductance, and intercellular CO2 concentration as well as various chlorophyll fluorescence parameters, which could contribute to enhanced accumulations of free proline and soluble sugars in seedlings after being subjected to a prolonged duration of osmotic stress. Furthermore, MT markedly improved antioxidant enzyme activities including superoxide dismutase, ascorbate peroxidase, catalase, and peroxidase along with the accumulation of ascorbic acid contributing to a significant reduction in reactive oxygen species under osmotic stress. In addition, the MT application induced a 978.12%, 33.54%, or 30.59% increase in endogenous MT, indole acetic acid, or gibberellic acid content under osmotic stress but did not affect the accumulation of abscisic acid. These findings suggest that an optimal concentration of MT (100 μmol·L−1) could relieve osmotic stress via improvement in osmotic adjustment, the enzymatic antioxidant defense system, and endogenous hormonal balance, thereby contributing to enhanced photosynthetic functions and growth of oat seedlings under water-limited conditions.