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International Journal of Molecular... Jun 2024Water deficit is the major stress factor magnified by climate change that causes the most reductions in plant productivity. Knowledge of photosystem II (PSII) response...
Water deficit is the major stress factor magnified by climate change that causes the most reductions in plant productivity. Knowledge of photosystem II (PSII) response mechanisms underlying crop vulnerability to drought is critical to better understanding the consequences of climate change on crop plants. Salicylic acid (SA) application under drought stress may stimulate PSII function, although the exact mechanism remains essentially unclear. To reveal the PSII response mechanism of celery plants sprayed with water (WA) or SA, we employed chlorophyll fluorescence imaging analysis at 48 h, 96 h, and 192 h after watering. The results showed that up to 96 h after watering, the stroma lamellae of SA-sprayed leaves appeared dilated, and the efficiency of PSII declined, compared to WA-sprayed plants, which displayed a better PSII function. However, 192 h after watering, the stroma lamellae of SA-sprayed leaves was restored, while SA boosted chlorophyll synthesis, and by ameliorating the osmotic potential of celery plants, it resulted in higher relative leaf water content compared to WA-sprayed plants. SA, by acting as an antioxidant under drought stress, suppressed phototoxicity, thereby offering PSII photoprotection, together with enhanced effective quantum yield of PSII photochemistry (Φ) and decreased quantity of singlet oxygen (O) generation compared to WA-sprayed plants. The PSII photoprotection mechanism induced by SA under drought stress was triggered by non-photochemical quenching (NPQ), which is a strategy to protect the chloroplast from photo-oxidative damage by dissipating the excess light energy as heat. This photoprotective mechanism, triggered by NPQ under drought stress, was adequate in keeping, especially in high-light conditions, an equal fraction of open PSII reaction centers (q) as of non-stress conditions. Thus, under water deficit stress, SA activates a regulatory network of stress and light energy partitioning signaling that can mitigate, to an extent, the water deficit stress on PSII functioning.
Topics: Photosystem II Protein Complex; Salicylic Acid; Plant Leaves; Chlorophyll; Apium; Droughts; Water; Photosynthesis; Dehydration; Stress, Physiological
PubMed: 38928427
DOI: 10.3390/ijms25126721 -
ACS Earth & Space Chemistry Jun 2024Hydrogen cyanide (HCN), a key molecule of significant importance in contemporary perspectives on prebiotic chemistry, originates in planetary atmospheres from various...
Hydrogen cyanide (HCN), a key molecule of significant importance in contemporary perspectives on prebiotic chemistry, originates in planetary atmospheres from various processes, such as photochemistry, thermochemistry, and impact chemistry, as well as from delivery by impacts. The resilience of HCN during periods of heavy bombardment, a phenomenon caused by an influx of material on unstable trajectories after accretion, remains relatively understudied. This study extensively investigates the stability of HCN under impact conditions simulated using a laboratory Nd:YAG laser in the ELISE experimental setup. High-resolution infrared spectroscopy was employed to monitor the gas phase composition during these simulations. Impact chemistry was simulated in bulk nitrogen atmospheres with varying mixing ratios of HCN and water vapor. The probed range of compositions spans from ∼0 to 1.8% of HCN and 0 to 2.7% of HO in a ∼1 bar nitrogen atmosphere. The primary decomposition products of HCN are CO and CO in the presence of water and unidentified solid phase products in dry conditions. Our experiments revealed a range of initial HCN decomposition rates between 2.43 × 10 and 5.17 × 10 molec J of input energy depending on the initial composition. Notably, it is shown that the decomposition process induced by the laser spark simulating the impact plasma is nonlinear, with the duration of the irradiation markedly affecting the decomposition rate. These findings underscore the necessity for careful consideration and allowance for margins when applying these rates to chemical models of molecular synthesis and decomposition in planetary atmospheres.
PubMed: 38919854
DOI: 10.1021/acsearthspacechem.4c00064 -
ACS ES&T Air Jun 2024Nitrous acid (HONO) is a key molecule in the reactive nitrogen cycle. However, sources and sinks for HONO are not fully understood. Particulate nitrate photochemistry...
Enhanced HONO Formation from Aqueous Nitrate Photochemistry in the Presence of Marine Relevant Organics: Impact of Marine-Dissolved Organic Matter (m-DOM) Concentration on HONO Yields and Potential Synergistic Effects of Compounds within m-DOM.
Nitrous acid (HONO) is a key molecule in the reactive nitrogen cycle. However, sources and sinks for HONO are not fully understood. Particulate nitrate photochemistry has been suggested to play a role in the formation of HONO in the marine boundary layer (MBL). Here we investigate the impact of marine relevant organic compounds on HONO formation from aqueous nitrate photochemistry. In particular, steady-state, gas-phase HONO yields were measured from irradiated nitrate solutions at low pH containing marine-dissolved organic matter (m-DOM). m-DOM induces a nonlinear increase in HONO yield across all concentrations compared to that for pure nitrate solutions, with rates of HONO formation increasing by up to 3-fold when m-DOM is present. Furthermore, to understand the potential synergistic effects that may occur within complex samples such as m-DOM, mixtures of chromophoric (light-absorbing) and aliphatic (non-light-absorbing) molecular proxies were utilized. In particular, mixtures of 4-benzoylbenzoic acid (4-BBA) and ethylene glycol (EG) in acidic aqueous solutions containing nitrate showed more HONO upon irradiation compared to solutions containing only one of the molecular proxies. This suggests that synergistic effects in the HONO formation can occur in complex organic samples. Atmospheric implications of the results presented here are discussed.
PubMed: 38898933
DOI: 10.1021/acsestair.4c00006 -
Polymers May 2024Responsive photonic crystal hydrogel sensors are renowned for their colorimetric sensing ability and can be utilized in many fields such as medical diagnosis,...
Responsive photonic crystal hydrogel sensors are renowned for their colorimetric sensing ability and can be utilized in many fields such as medical diagnosis, environmental detection, food safety, and industrial production. Previously, our group invented responsive photonic nanochains (RPNCs), which improve the response speed of photonic crystal hydrogel sensors by at least 2 to 3 orders of magnitude. However, RPNCs are dispersed in a liquid medium, which needs a magnetic field to orient them for the generation of structural colors. In addition, during repeated use, the process of cleaning and redispersing can cause entanglement, breakage, and a loss of RPNCs, resulting in poor stability. Moreover, when mixing with the samples in liquid, the RPNCs may lead to the contamination of the samples being tested. In this paper, we incorporate one-dimensional oriented RPNCs with agarose gel film to prepare heterogeneous hydrogel films. Thanks to the non-responsive and porous nature of the agarose gel, the protons diffuse freely in the gel, which facilitates the fast response of the RPNCs. Furthermore, the "frozen" RPNCs in agarose gel not only enable the display of structural colors without the need for a magnet but also improve the cycling stability and long-term durability of the sensor, and will not contaminate the samples. This work paves the way for the application of photonic crystal sensors.
PubMed: 38891476
DOI: 10.3390/polym16111530 -
Polymers May 2024Additive manufacturing (AM) has revolutionised the manufacturing industry, offering versatile capabilities for creating complex geometries directly from a digital...
Additive manufacturing (AM) has revolutionised the manufacturing industry, offering versatile capabilities for creating complex geometries directly from a digital design. Among the various 3D printing methods for polymers, vat photopolymerisation combines photochemistry and 3D printing. Despite the fact that single-epoxy 3D printing has been explored, the fabrication of multi-material bioderived epoxy thermosets remains unexplored. This study introduces the feasibility and potential of multi-material 3D printing by means of a dual-vat Digital Light Processing (DLP) technology, focusing on bioderived epoxy resins such as ELO (epoxidized linseed oil) and DGEVA (vanillin alcohol diglycidyl ether). By integrating different materials with different mechanical properties into one sample, this approach enhances sustainability and offers versatility for different applications. Through experimental characterisation, including mechanical and thermal analysis, the study demonstrates the ability to produce structures composed of different materials with tailored mechanical properties and shapes that change on demand. The findings underscore the promising technology of dual-vat DLP technology applied to sustainable bioderived epoxy monomers, allowing sustainable material production and complex structure fabrication.
PubMed: 38891457
DOI: 10.3390/polym16111510 -
Beilstein Journal of Nanotechnology 2024Laser synthesis and processing of colloids (LSPC) is an established method for producing functional and durable nanomaterials and catalysts in virtually any liquid of... (Review)
Review
Laser synthesis and processing of colloids (LSPC) is an established method for producing functional and durable nanomaterials and catalysts in virtually any liquid of choice. While the redox reactions during laser synthesis in water are fairly well understood, the corresponding reactions in organic liquids remain elusive, particularly because of the much greater complexity of carbon chemistry. To this end, this article first reviews the knowledge base of chemical reactions during LSPC and then deduces identifiable reaction pathways and mechanisms. This review also includes findings that are specific to the LSPC method variants laser ablation (LAL), fragmentation (LFL), melting (LML), and reduction (LRL) in organic liquids. A particular focus will be set on permanent gases, liquid hydrocarbons, and solid, carbonaceous species generated, including the formation of doped, compounded, and encapsulated nanoparticles. It will be shown how the choice of solvent, synthesis method, and laser parameters influence the nanostructure formation as well as the amount and chain length of the generated polyyne by-products. Finally, theoretical approaches to address the mechanisms of organic liquid decomposition and carbon shell formation are highlighted and discussed regarding current challenges and future perspectives of LSPC using organic liquids instead of water.
PubMed: 38887526
DOI: 10.3762/bjnano.15.54 -
Frontiers in Plant Science 2024Energy efficient lighting strategies have received increased interest from controlled environment producers. Long photoperiods (up to 24 h - continuous lighting (CL)) of...
Energy efficient lighting strategies have received increased interest from controlled environment producers. Long photoperiods (up to 24 h - continuous lighting (CL)) of lower light intensities could be used to achieve the desired daily light integral (DLI) with lower installed light capacity/capital costs and low electricity costs in regions with low night electricity prices. However, plants grown under CL tend to have higher carbohydrate and reactive oxygen species (ROS) levels which may lead to leaf chlorosis and down-regulation of photosynthesis. We hypothesize that the use of dynamic CL using a spectral change and/or light intensity change between day and night can negate CL-injury. In this experiment we set out to assess the impact of CL on pepper plants by subjecting them to white light during the day and up to 150 µmol m s of monochromatic blue light at night while controlling the DLI at the same level. Plants grown under all CL treatments had similar cumulative fruit number and weight compared to the 16h control indicating no reduction in production. Plants grown under CL had higher carbohydrate levels and ROS-scavenging capacity than plants grown under the 16h control. Conversely, the amount of photosynthetic pigment decreased with increasing nighttime blue light intensity. The maximum quantum yield of photosystem II (F/F), a metric often used to measure stress, was unaffected by light treatments. However, when light-adapted, the operating efficiency of photosystem II (ΦPSII) decreased and non-photochemical quenching (NPQ) increased with increasing nighttime blue light intensity. This suggests that both acclimated and instantaneous photochemistry during CL can be altered and is dependent on the nighttime light intensity. Furthermore, light-adapted chlorophyll fluorescence measurements may be more adept at detecting altered photochemical states than the conventional stress metric using dark-adapted measurements.
PubMed: 38882573
DOI: 10.3389/fpls.2024.1372886 -
Scientific Reports Jun 2024This study presents a thorough spectroscopic analysis of TiO-Pt systems under LED irradiation, with a focus on elucidating the photodeposition process of Pt...
This study presents a thorough spectroscopic analysis of TiO-Pt systems under LED irradiation, with a focus on elucidating the photodeposition process of Pt nanoparticles onto TiO surfaces. The methodology leverages an innovative LED photoreactor tailored to a specific spectral range, enabling precise characterization of the excitation spectrum of TiO-Pt composites. Through the identification of Pt precursor species and their excitation under LED-UV light, a photodeposition mechanism is proposed involving concurrent excitation of both the TiO semiconductor and the HPtCl precursor. The LED photoreactors are employed to scrutinize the excitation profile of TiO-Pt materials, revealing that the incorporation of Pt nanoparticles does not expand TiO's absorption spectrum. Furthermore, UV-A exposure in the absence of Pt did not induce the formation of surface defects, underscoring the lack of visible light activity in TiO-Pt systems. Spectroscopic analyses, complemented by naproxen photooxidation experiments, indicate the absence of a significant plasmonic effect in Pt nanoparticles within the experimental framework. Mass spectroscopy results corroborate the presence of distinct naproxen degradation pathways, suggesting minimal influence from photocatalyst properties. This research provides a detailed spectroscopic insight into TiO-Pt photocatalysis, enriching the knowledge of photocatalytic materials in LED lighting.
PubMed: 38879712
DOI: 10.1038/s41598-024-64748-4 -
Ultrasonics Sonochemistry Jun 20241,3,5-triazine derivatives are useful compounds with potential applications in various branches of chemical industry, including pharmaceutical chemistry, cosmetic...
1,3,5-triazine derivatives are useful compounds with potential applications in various branches of chemical industry, including pharmaceutical chemistry, cosmetic chemistry, photochemistry, and organic chemistry. Due to the growing environmental requirements on conducting efficient, economical, and safe syntheses, development of new methods for synthesizing organic compounds is highly desirable. In this publication, we present a protocol for the synthesis of 1,3,5-triazine derivatives using a sonochemical approach. In as little as 5 min, it is possible to obtain most of the investigated compounds with a yield of over 75%. An undeniable advantage of this method, besides its short time, is the use of water as the solvent. Furthermore, we provide examples that the sonochemical method may be more versatile than the competing microwave method. Analysis conducted using the DOZN 2.0 tool revealed that in terms of the 12 principles of green chemistry, the developed sonochemical method is 13 times "greener" than the classical one. Additionally, it has been demonstrated that the investigated molecules are attractive for their application as drug-like compounds.
PubMed: 38878716
DOI: 10.1016/j.ultsonch.2024.106951 -
Nature Communications Jun 2024Direct solar-to-hydrogen conversion from pure water using all-organic heterogeneous catalysts remains elusive. The challenges are twofold: (i) full-band low-frequent...
Direct solar-to-hydrogen conversion from pure water using all-organic heterogeneous catalysts remains elusive. The challenges are twofold: (i) full-band low-frequent photons in the solar spectrum cannot be harnessed into a unified S excited state for water-splitting based on the common Kasha-allowed S → S excitation; (ii) the H → H evolution suffers the high overpotential on pristine organic surfaces. Here, we report an organic molecular crystal nanobelt through the self-assembly of spin-one open-shell perylene diimide diradical anions (:PDI) and their tautomeric spin-zero closed-shell quinoid isomers (PDI). The self-assembled :PDI/PDI crystal nanobelt alters the spin-dependent excitation evolution, leading to spin-allowed SS → (TT) → T + T singlet fission under visible-light (420 nm~700 nm) and a spin-forbidden S → T transition under near-infrared (700 nm~1100 nm) within spin-hybrid chromophores. With a triplet-triplet annihilation upconversion, a newly formed S excited state on the diradical-quinoid hybrid induces the H reduction through a favorable hydrophilic diradical-mediated electron transfer, which enables simultaneous H and O production from pure water with an average apparent quantum yield over 1.5% under the visible to near-infrared solar spectrum.
PubMed: 38871750
DOI: 10.1038/s41467-024-49511-7