Search Results (205)

Cowpea (Vigna unguiculata (L.) Walp.) is a vital legume crop recognized for its nutritional value and adaptability to various growing conditions. However, exposure of cowpea to drought stress during the early growth stages can significantly restrict growth and yield potential. Therefore, identifying cowpea genotypes tolerant to drought during early growth and development is essential for maintaining yield potential. This study characterized 15 diverse cowpea genotypes for various physiological, pigment, and morphological traits that may contribute to drought tolerance. At the V2 stage, the cowpea genotypes were subjected to two moisture regimes: control (100% irrigation) and drought (50% irrigation) for 22 days to assess trait responses and their relationship to drought tolerance. Drought-stressed plants decreased stomatal conductance by 79%, negatively correlating with a 2.9 °C increase in canopy temperature. Under drought, the photochemical reflectance index (PRI) was strongly associated with the quantum yield of PSII and electron transport rate. Shoot biomass decreased by 51% and root biomass by 32% under drought. Leaf area and shoot weight were correlated with root traits such as total length, surface area, and weight. Among all genotypes, 280785-11 and UCR 1004 demonstrated superior rooting vigor under drought, emphasizing their efficiency in resource utilization. These findings highlight the relevance of utilizing drought-adaptive traits to improve early-season drought tolerance. Full article

Photolabile protecting groups (PPGs), also known as caging groups, are valuable tools in photopharmacology. They enable precise control over the release of bioactive compounds from the corresponding caged compounds at a precisely controlled time and place using light of specific wavelengths. This study introduces a novel approach to fine-tuning the photophysical and photochemical properties of visible-light-sensitive dicyanocoumarin- and COUPY-based caging groups by incorporating a phenyl group in a position adjacent to the photolabile bond. Our photoactivation studies with visible light demonstrated that this structural modification slightly improved the photolytic efficiency of both dicyanocoumarin- and COUPY-caged model compounds compared to their methyl-substituted or unsubstituted counterparts. Furthermore, COUPY PPGs were efficiently photoactivated with red light (620 nm) and successfully used to cage two antitumor drugs, chlorambucil and 4-phenylbutyric acid. These findings highlight the potential of phenyl-containing caging groups based on dicyanocoumarin and COUPY scaffolds as versatile platforms for developing new light-activated tools for photopharmacology applications. Full article

Recent research on the use of heptazine-based polymeric carbon nitride materials as potential photocatalysts for hydrogen evolution has made significant progress. However, the impact of the water cluster’s size on the time-dependent photochemical mechanisms during the water splitting process of heptazine–water clusters remains largely unexplored. Here, we present a Landau–Zener trajectory surface hopping dynamics calculation for heptazine–(H₂O)₄ clusters at the ADC(2) level. The electron-driven proton transfer (EDPT) mechanism reaction from water to hydrogen-bonded heptazine–water clusters was confirmed using this method, yielding a heptazinyl radical and an OH biradical as products. The calculated quantum yield of the EDPT for the heptazine–(H₂O)₄ complex was 6.5%, which was slightly lower than that of the heptazine–H₂O complex (9%), suggesting that increasing the water cluster size does not significantly enhance the efficiency of hydrogen transfer. Interestingly, our results show that the de-excitation of the heptazine–water complex from the excited state to the ground state via the EDPT process follows both fast and slow decay modes, which govern population relaxation and facilitate the photochemical water splitting reaction. This newly identified differential decay behavior offers valuable insights that could help deepen our understanding of the EDPT process, potentially improving the efficiency of water splitting under sunlight. Full article

The super high-density (SHD) production system has recently been introduced to the Chilean European plum (Prunus domestica L.) industry, but the potential of applying regulated deficit irrigation (RDI) in this system remains unexplored. As irrigation water availability in Chile has been strongly jeopardized by climate change, there is an urgent need to validate water-conserving practices in modern production systems. A field study was conducted in a commercial SHD European plum orchard (cv. French grafted on Rootpac-20 rootstock) for two consecutive seasons in Peralillo, O’Higgins Region, Chile. The objective of this study was to assess the impact of a late water deficit (LD) on water productivity, fruit quality, plant water relations, and soil microbiota. The results showed that implementing LD enhanced water productivity by 40% without compromising fresh and dry fruit quality. Moderate to severe water stress induced no changes in physiological parameters such as stomatal conductance and photochemical efficiency. Additionally, the LD treatment significantly reduced soil moisture but increased the abundance of certain groups of beneficial soil microbiota and fine roots. These results highlight the potential of LD as a viable water-conserving practice in modern SHD European plum orchards, particularly in regions facing water scarcity due to climate change. Full article

Mercury (Hg) poses significant risks to human health, the environment, and plant physiology, with its effects influenced by chemical form, concentration, exposure route, and organism vulnerability. This study evaluates the physiological impacts of Hg on Handroanthus impetiginosus (Ipê Roxo) seedlings through SPAD index measurements, chlorophyll fluorescence analysis, and Hg quantification in plant tissues. Four-month-old seedlings were exposed for eight days to distilled water containing Hg at 0, 1, 3, 5, and 7 mg L⁻¹. The SPAD index decreased by 28.17% at 3, 5, and 7 mg L⁻¹, indicating reduced photosynthetic capacity. Chlorophyll a fluorescence analysis revealed a 50.58% decline in maximum efficiency (Fv/Fm) and a 58.33% reduction in quantum yield (ΦPSII) at 7 mg L⁻¹, along with an 83.04% increase in non-photochemical quenching (qn), suggesting oxidative stress and PSII damage. Transpiration decreased by 26.7% at 1 mg L⁻¹ and by 55% at 3, 5, and 7 mg L⁻¹, correlating with Hg levels and leaf senescence. Absorption, translocation, bioconcentration, and bioaccumulation factors varied among treatments. Hg accumulated mainly in stems (40.23 μg g⁻¹), followed by roots (0.77 μg g⁻¹) and leaves (2.69 μg g⁻¹), with limited translocation to leaves. These findings highlight Hg’s harmful effects on H. impetiginosus, an ecologically and commercially valuable species, addressing a gap in research on its Hg tolerance and phytoremediation potential. Full article

The objective of this study was to examine the impact of various foliar fertilization treatments on the growth of new shoots, photosynthetic characteristics of leaves, and mineral nutrient content in the leaves of ‘Marselan’ grapevines. Five distinct combinations of nano zero-valent iron (n ZVI), compound sodium nitrophenolate (CSN), and potassium dihydrogen phosphate (KH₂PO₄) were administered through foliar application to ‘Marselan’ grapevines cultivated in the Wuwei region of the Hexi Corridor, with water spray serving as the control treatment. The results showed that T5 treatment (15 mg·L⁻¹ n ZVI + 0.4 g·L⁻¹ CSN + 2.5 g·L⁻¹ KH₂PO₄) significantly increased the leaf area and SPAD value of ‘Marselan’ grapes; T4 treatment (15 mg·L⁻¹ n ZVI + 0.4 g·L⁻¹ CSN + 1.67 g·L⁻¹ KH₂PO₄) significantly increased the internode length of new grape shoots. T5 treatment was favorable to increase the basic coarseness of new grape shoots, the net photosynthetic rate of the leaves, and stomatal conductance; leaf transpiration rate was the highest under the T4 and T5 treatments; T3 (15 mg·L⁻¹ n ZVI + 0.4 g·L⁻¹ CSN + 1.25 g·L⁻¹ KH₂PO₄), T4, and T5 treatments could improve leaf initial fluorescence at different periods. At 45 days after flowering, the maximum photochemical efficiency under the T3 and T4 treatments reached the highest value throughout the period, and the T3 treatment improved leaf potential maximum quantum yield. Meanwhile, the leaf nitrogen and phosphorus content under the T5 treatment were the highest in the five periods. Additionally, the contents of potassium (K), manganese (Mn), copper (Cu), and zinc (Zn) in the leaves increased significantly under the T4 and T5 treatments. The following conclusions emerged from a comprehensive analysis: the T4 treatment was the best, and the T5 treatment was the second most effective. Full article

In order to explore the effects of different irrigation methods on the physiological characteristics of mulch-free cotton in southern Xinjiang, the following experiments were carried out: (1) Different irrigation amount test: 300, 375, 450, 525, and 600 mm (represented by W1, W2, W3, W4, and W5) and a control (450 mm for film-covered cotton, represented by WCK) were set. (2) Drip irrigation frequency test: drip irrigation 12, 10, 8, and 6 times during the growth period (expressed by P12, P10, P8, and P6). Soil water dynamics, root distribution dynamics, chlorophyll fluorescence, leaf area index (LAI), SPAD (chlorophyll density), stress enzyme activities, and MDA (malondialdehyde) content were observed. The results showed that the average maximum change range of soil water content in the cotton field without film mulching was ±17.7%, which was 1.35 times higher than that in the cotton field with film mulching. Compared with cotton with film mulching, the root distribution characteristics of mulch-free cotton in the surface soil (0–20 cm) and the periphery (30 cm from the main root) decreased by 33.55–74.48% and 14.07–102.18%, respectively, while the root distribution characteristics in the deep layer (40–60 cm) increased by 49.62–242.67%, its average leaf green fluorescence parameters decreased by 9.03–50.44%, the activities of protective enzymes (SOD: superoxide dismutase, POD: peroxidase) decreased by 3.36–3.58%, the SPAD value decreased by 5.55%, and the MDA content increased by 3.17%, indicating that mulch-free cotton reduced the physiological function of cotton leaves, and the yield decreased by 42.07%. In the mulch-free treatments, the average root growth indexes were W2 > W3 > W4 > W5 > W1 and P12 > P10 > P8 > P6, and there was little difference between W2 and W3 and P12 and P10. With the increase in irrigation water and irrigation frequency, the initial fluorescence (F₀) of leaves in each period of mulch-free cotton showed a downward trend, and the maximum fluorescence (F_m), variable fluorescence (F_V), maximum photochemical efficiency (F_V/F_m), potential photochemical activity of PS II (F_V/F₀), electron transfer of PS II (F_m/F₀), and photosynthetic performance index (PIABS) showed an upward trend. In all water treatments, W3 and P12 had the highest SPAD value, protective enzyme activity, and the lowest MDA content, which was significantly different from other treatments except W4 and P10. The yield order of different treatments was W3 > W4 > W5 > W2 > W1, and the difference between W3 and W4 was not significant, but significant with W2 and W1. The irrigation frequency test was P12 > P10 > P8 > P6, and there was no significant difference between P12 and P10. We find that in the mulch-free treatment, all indicators of W3, W2, P12, and P10 were relatively high. It can be concluded that no mulching has a certain impact on cotton root distribution and leaf physiological function. When the irrigation amount is 450–525 mm and irrigation times is 10–12, it is beneficial for promoting root growth and plays a role in leaf physiological function, and the water use efficiency (WUE) is high, which can provide reference for the scientific water management of mulch-free cotton in production practice. Full article

The tomato is among the crops with the most extensive cultivated area and greatest consumption in our nation; nonetheless, secondary salinization of facility soil significantly hinders the sustainable growth of facility agriculture. Melatonin (MT), as an innovative plant growth regulator, is essential in stress responses. This research used a hydroponic setup to replicate saline stress conditions. Different endogenous levels of melatonin (MT) were established by foliar spraying of 100 μmol·L⁻¹ MT, the MT synthesis inhibitor p-CPA (100 μmol·L⁻¹), and a combination of p-CPA and MT, to investigate the mechanism by which MT mitigates the effects of salt stress on the photosynthetic efficiency of tomato seedlings. Results indicated that after six days of salt stress, the endogenous MT content in tomato seedlings drastically decreased, with declines in the net photosynthetic rate and photosystem performance indices (PI_total and PI_abs). The OJIP fluorescence curve exhibited distortion, characterized by anomalous K-band and L-band manifestations. Exogenous MT dramatically enhanced the gene (TrpDC, T5H, SNAcT, and AcSNMT) expression of critical enzymes in MT synthesis, therefore boosting the level of endogenous MT. The application of MT enhanced the photosynthetic parameters. MT treatment decreased the fluorescence intensities of the J-phase and I-phase in the OJIP curve under salt stress, attenuated the irregularities in the K-band and L-band performance, and concurrently enhanced quantum yield and energy partitioning ratios. It specifically elevated φP_o, φE_o, and ψ_o, while decreasing φD_o. The therapy enhanced parameters of both the membrane model (ABS/RC, DI_o/RC, ET_o/RC, and TR_o/RC) and leaf model (ABS/CS_m, TR_o/CS_m, ET_o/CS_m, and DI_o/CS_m). Conversely, the injection of exogenous p-CPA exacerbated salt stress-related damage to the photosystem of tomato seedlings and diminished the beneficial effects of MT. The findings suggest that exogenous MT mitigates salt stress-induced photoinhibition by (1) modulating endogenous MT concentrations, (2) augmenting PSII reaction center functionality, (3) safeguarding the oxygen-evolving complex (OEC), (4) reinstating PSI redox potential, (5) facilitating photosynthetic electron transport, and (6) optimizing energy absorption and dissipation. As a result, MT markedly enhanced photochemical performance and facilitated development and salt stress resilience in tomato seedlings. Full article

Carbon dioxide (CO₂) can be electrochemically, thermally, and photochemically reduced into valuable products such as carbon monoxide (CO), formic acid (HCOOH), methane (CH₄), and methanol (CH₃OH), contributing to carbon footprint mitigation. Extensive research has focused on catalysts, combining experimental approaches with computational quantum mechanics to elucidate reaction mechanisms. Although computational studies face challenges due to a lack of accurate approximations, they offer valuable insights and assist in selecting suitable catalysts for specific applications. This study investigates the electrocatalytic pathways of CO₂ reduction on cuprous oxide (Cu₂O) catalysts, utilizing the computational hydrogen electrode (CHE) model based on density functional theory (DFT). The electrocatalytic performance of flat Cu₂O (100) and hexagonal Cu₂O (111) surfaces was systematically analysed, using the standard hydrogen electrode (SHE) as a reference. Key parameters, including free energy changes (ΔG), adsorption energies (E_ads), reaction mechanisms, and pathways for various intermediates were estimated. The results showed that CO₂ was reduced to CO_(g) on both Cu₂O surfaces at low energies. However, methanol (CH₃OH) production was observed preferentially on Cu₂O (111) at ΔG = −1.61 eV, whereas formic acid (HCOOH) and formaldehyde (HCOH) formation were thermodynamically unfavourable at interfacial sites. The CO₂-to-methanol conversion on Cu₂O (100) exhibited a total ΔG of −3.38 eV, indicating lower feasibility compared to Cu₂O (111) with ΔG = −5.51 eV. These findings, which are entirely based on a computational approach, highlight the superior catalytic efficiency of Cu₂O (111) for methanol synthesis. This approach also holds the potential for assessing the catalytic performance of other transition metal oxides (e.g., nickel oxide, cobalt oxide, zinc oxide, and molybdenum oxide) and their modified forms through doping or alloying with various elements. Full article

High temperatures have adverse impacts on the photosynthetic efficiency and yield of many crop plants. This study investigated how high temperatures affect the photosynthetic efficiency parameters and chloroplast ultrastructure of three edamame cultivars (AGS354, UVE17, and UVE14) at the reproductive stages (flowering and pod-filling). Heat stress (HS) treatments were performed under controlled conditions in climate chambers set at 25/18 °C (control), 30/23 °C (HS-I), and 35/28 °C (HS-II). The AGS354 cultivar exhibited the greatest susceptibility under HS-II treatment, characterised by a reduction in the photochemical reactions, decreased chlorophyll-a (chl-a) and carotenoid accumulation, the highest increase in the starch grain traits, and reduced plastoglobule and grana area traits. In UVE 14 and UVE17, the HS-II treatment enhanced chl-a and chl-b accumulation. Elevated carotenoid levels in UVE14 and UVE17 likely protected chlorophyll from degradation and mitigated photooxidative damage. The HS-II treatment also enhanced the grana traits, supporting improved light-harvesting capacity during heat stress in UVE14 and 17. However, heat stress disrupted the photochemical reactions (quantum efficiency of photosystem II, performance index absorbance, and performance index), indicating that elevated carotenoids alone do not exhibit complete tolerance to heat stress. Since plastoglobules play an essential in carotenoid biosynthesis, increased or stabilised plastoglobule traits in UVE14 and UVE17 under HS-II treatment strongly indicate improved heat stress tolerance. Overall, UVE14 and UVE17 emerged as the most heat-tolerant cultivars, with AGS354 being the most susceptible. These findings provide valuable insights into heat stress adaptation mechanisms and suggest the UVE14 and UVE17 cultivars as potential candidates for breeding heat-tolerant edamame cultivars. Full article

Wheat (Triticum aestivum L.) is a globally important staple crop; however, its growth and yield are severely limited by drought stress. This study evaluated the effects of a combined microbial inoculant, Streptomyces pactum Act12 and Streptomyces rochei D74, on wheat photosynthesis, physiological traits, and yield under drought conditions. Key physiological and yield parameters were measured during the jointing, heading, and grain-filling stages. Drought stress significantly reduced chlorophyll content, maximum photochemical efficiency of photosystem II (PSII) (Fv/Fm), and antioxidant enzyme activities, while increasing malondialdehyde (MDA) levels, leading to a notable yield decline. In contrast, inoculation with Streptomyces strains alleviated these adverse effects, with the combined inoculant (Act12+D74) group demonstrating the most significant improvement. Chlorophyll content increased by up to 32.60%, Fv/Fm improved by 43.07%, and antioxidant enzyme activities were enhanced, with superoxide dismutase (SOD) activity increasing by 19.32% and peroxidase (POD) activity by 75.44%. Meanwhile, MDA levels were reduced by 61.61%. The proline content in the combined inoculant group increased by 90.44% at the jointing stage and the soluble protein content increased by 60.17% at the heading stage. Furthermore, it improved the yield by 26.19% by increasing both effective spikes and grains per spike. For the first time, this study revealed the synergistic effects of Act12 and D74 in enhancing photosynthesis, strengthening antioxidant defenses, and optimizing osmotic regulation under drought conditions. These findings provide a theoretical basis for developing environmentally friendly drought management strategies and highlight the potential applications of this inoculant in sustainable agriculture. Full article

In this study we report on the efficiency of a furane-indole-chromenone-based organic derivative (FIC) as a photocatalyst in the α-arylation of enol acetate upon LED irradiation at 405 nm, and as a photoinitiator/photocatalyst in the free radical polymerization of an acrylate group in the presence of bis-(4-tert-butylphenyl)iodonium hexafluorophosphate (Iod) as an additive, or in the presence of both Iod and ethyl-4-(dimethyl amino) benzoate (EDB) under LED irradiation at 365 nm. The photochemical properties of this new light-sensitive compound are described, and the wide redox window (3.27 eV) and the high excited-state potentials FIC*/FIC^●− (+2.64 V vs. SCE) and FIC^●+/FIC* (−2.41 V vs. SCE) offered by this photocatalyst are revealed. The chemical mechanisms that govern the radical chemistry are discussed by means of different techniques, including fluorescence-quenching experiments, UV-visible absorption and fluorescence spectroscopy, and cyclic voltammetry analysis. Full article

This article presents a comprehensive examination of the combined catalytic conversion technology for nitrogen oxides (NOx) and volatile organic compounds (VOCs), which are the primary factors contributing to the formation of photochemical smog, ozone, and PM2.5. These pollutants present a significant threat to air quality and human health. The article examines the reaction mechanism and interaction between photocatalytic technology and NH₃-SCR catalytic oxidation technology, highlighting the limitations of the existing techniques, including catalyst deactivation, selectivity issues, regeneration methods, and the environmental impacts of catalysts. Furthermore, the article anticipates prospective avenues for research, underscoring the necessity for the development of bifunctional catalysts capable of concurrently transforming NOx and VOCs across a broad temperature spectrum. The review encompasses a multitude of integrated catalytic techniques, including selective catalytic reduction (SCR), photocatalytic oxidation, low-temperature plasma catalytic technology, and biological purification technology. The article highlights the necessity for further research into catalyst design principles, structure–activity relationships, and performance evaluations in real industrial environments. This research is required to develop more efficient, economical, and environmentally friendly waste gas treatment technologies. The article concludes by outlining the importance of collaborative management strategies for VOC and NOx emissions and the potential of combined catalytic conversion technology in achieving these goals. Full article

Chemical weed control is a significant agricultural concern, and reliance on a limited range of herbicide action modes has increased resistant weed species, many of which use C4 metabolism. As a result, the identification of novel herbicidal agents with low toxicity targeting C4 plants becomes imperative. An assessment was conducted on the impact of 3-cyanobenzoic acid on the growth and photosynthetic processes of maize (Zea mays), a representative C4 plant, cultivated hydroponically over 14 days. The results showed a significant reduction in plant growth and notable disruptions in gas exchange and chlorophyll a fluorescence due to the application of 3-cyanobenzoic acid, indicating compromised photosynthetic activity. Parameters such as the chlorophyll index, net assimilation (A), stomatal conductance (g_s), intercellular CO₂ concentration (C_i), maximum effective photochemical efficiency (F_v′/F_m′), photochemical quenching coefficient (q_P), quantum yield of photosystem II photochemistry (ϕ_PSII), and electron transport rate through PSII (ETR) all decreased. The A/PAR curve revealed reductions in the maximum net assimilation rate (A_max) and apparent quantum yield (ϕ), alongside an increased light compensation point (LCP). Moreover, 3-cyanobenzoic acid significantly decreased the carboxylation rates of RuBisCo (V_cmax) and PEPCase (V_pmax), electron transport rate (J), and mesophilic conductance (g_m). Overall, 3-cyanobenzoic acid induced substantial changes in plant growth, carboxylative processes, and photochemical activities. The treated plants also exhibited heightened susceptibility to intense light conditions, indicating a significant and potentially adverse impact on their physiological functions. These findings suggest that 3-cyanobenzoic acid or its analogs could be promising for future research targeting photosynthesis. Full article

An advanced photochemical reduction system involving the UV/Fe(III)–oxalate system was developed for the reduction of nitrate (NO₃⁻) to harmless N-gaseous species, primarily nitrogen (N₂), by carbon dioxide radical (·CO₂⁻) generated in the presence of dissolved oxygen (DO). Electron paramagnetic resonance (EPR) analyses confirmed the presence of both ·CO₂⁻ and ·OH radicals. Systematic investigations were conducted on various operational parameters, such as the initial Fe(III) concentration, oxalate concentration, and pH levels, to assess their impacts on the efficiency and products of NO₃⁻ reduction. Notably, solution pH played a significant role in influencing the NO₃⁻ reduction efficiency and the final products. At pH 2, approximately 75% of NO₃⁻ was converted into N₂ with an 80% selectivity. In the pH range of 3 to 5, a remarkable NO₃⁻ removal rate of about 90% was achieved. Furthermore, higher concentrations of Fe(III) (2 mM) and oxalate (10 mM) were found to enhance NO₃⁻ removal to 91.95% and 88.71%, respectively. The presence of DO increased the oxidative potential in the reaction system, subsequently enhancing the selectivity conversion of NO₃⁻ to N₂. In summary, the UV/Fe(III)–oxalate system exhibits significant potential for effective removal of NO₃⁻ while achieving high selectivity for the production of N₂ in water remediation applications. Full article