Covalent organic frameworks (COFs) are promising photocatalysts for H2O2 production from water via oxygen reduction reactions (ORR). The design of COFs for efficient H2O2 production indubitably hinges on an in-depth understanding of their ORR mechanisms. In this work, taking an imine-linked COF as an example, we demonstrate that protonation of the functional units such as imine, amine, and triazine, is a highly efficient strategy to upgrade the activity levels for H2O2 synthesis. The protonation not only extends the light absorption of the COF but also provides proton sources that directly participate in H2O2 generation. Notably, the protonation simplifies the reaction pathways of ORR to H2O2, i.e. from an indirect superoxide radical ([[EQUATION]]) mediated route to a direct one-step two-electron route. Theoretical calculations confirm that the protonation favors H2O2 synthesis due to easy access of protons near the reaction sites that removes the energy barrier for generating *OOH intermediate. These findings not only extend the mechanistic insight into H2O2 photosynthesis but also provide a rational guideline for the design and upgradation of efficient COFs.
Dispersion of single atoms (SAs) in the host is important for optimizing catalytic activity. Herein, we propose a novel strategy to tune oxygen vacancies in CeO2-X directionally anchoring the single atom platinum (PtSA), which is uniformly dispersed on the rGO. The catalyst's performance for the hydrogen evolution reaction (HER) can be enhanced by controlling different densities of CeO2-X in rGO. The PtSA performs best optimally densified and loaded on homogeneous and moderately densified CeO2-X/rGO (PtSA-M-CeO2-X/rGO). It exhibited high activity in HER with an overpotential of 25 mV at 0.5 M H2SO4 and 33 mV at 1 KOH than that of almost reported electrocatalysts. Furthermore, it exhibited stability for 90 hours at -100 mA cm-2 in 1 KOH and -150 mA cm-2 in 0.5 M H2SO4 conditions, respectively. Through comprehensive experiments and theoretical calculations, the suitable dispersion density of PtSA on the defects of CeO2-X with more active sites gives the potential for practical applications. This research paves the way for developing single-atom catalysts with exceptional catalytic activity and stability, holding promise in advanced green energy conversion through defects engineering.
BACKGROUND: PIN-FORMED genes (PINs) are crucial in plant development as they determine the directionality of auxin flow. They are present in almost all land plants and even in green algae. However, their role in fern development has not yet been determined. This study aims to investigate the function of CrPINMa in the quasi-model water fern Ceratopteris richardii. RESULTS: CrPINMa possessed a long central hydrophilic loop and characteristic motifs within it, which indicated that it belonged to the canonical rather than the non-canonical PINs. CrPINMa was positioned in the lineage leading to Arabidopsis PIN6 but not that to its PIN1, and it had undergone numerous gene duplications. CRISPR/Cas9 genome editing had been performed in ferns for the first time, producing diverse mutations including local frameshifts for CrPINMa. Plants possessing disrupted CrPINMa exhibited retarded leaf emergence and reduced leaf size though they could survive and reproduce at the same time. CrPINMa transcripts were distributed in the shoot apical meristem, leaf primordia and their vasculature. Finally, CrPINMa proteins were localized to the plasma membrane rather than other cell parts. CONCLUSIONS: CRISPR/Cas9 genome editing is feasible in ferns, and that PINs can play a role in fern leaf development.
Membrane Transport Proteins , Plant Leaves , Plant Proteins , Pteridaceae , CRISPR-Cas Systems , Gene Editing , Gene Expression Regulation, Plant , Membrane Transport Proteins/genetics , Membrane Transport Proteins/metabolism , Plant Leaves/genetics , Plant Leaves/growth & development , Plant Leaves/metabolism , Plant Proteins/genetics , Plant Proteins/metabolism , Pteridaceae/genetics , Pteridaceae/metabolism , Pteridaceae/growth & development
Designing and fabricating highly efficient oxygen evolution reaction (OER) electrocatalytic materials for water splitting is a promising and practical approach to green and sustainable low-carbon energy systems. Herein, a facile in situ growth self-template strategy by using ZIF-67 as a consumable layered double hydroxides (LDHs) template and silver nanowires (AgNWs) as 1D conductive cascaded substrate to controllably synthesize the target AgNWs@CoFe-LDH composites with unique hollow shell sugar gourd-like structure and enhanced directional electron transport effect is reported. The AgNWs exhibit the key functions of the close connection of CoFe-LDH nanocages and the support of the directional electron transport effect in the composite catalyst inducing electrons directionally moving from CoFe-LDH to AgNWs. Meanwhile, the CoFe-LDH nanocages with ultrathin nanosheets and hollow structural properties show abundant active sites for electrocatalytic oxygen generation. The versatile AgNWs@CoFe-LDH catalyst with optimized components, enhanced directional electron transport, and synergistic effect achieves high OER performance with the overpotential of 207 mV and long-term 50 h stability at 10 mA cm-2 in an alkaline medium. Moreover, in-depth insights into the microstructure, structure-activity relationships, identification of key intermediate species, and a proton-coupled four-electron OER mechanism based on experimental discovery and theoretical calculation are also demonstrated.
BACKGROUND AND AIMS: In flowering plants, regeneration can be achieved by a variety of approaches, and different sets of transcriptional factors are involved in these processes. However, regeneration in taxa other than flowering plants remains a mystery. Ceratopteris richardii is a representative fern capable of both direct and indirect organogenesis, and we aimed to investigate the genetics underlying the transition from callus proliferation to differentiation. METHODS: Morphological and histological analyses were used to determine the type of regeneration involved. RNA sequencing and differential gene expression were used to investigate how the callus switches from proliferation to differentiation. Phylogenetic analysis and RNA in situ hybridization were used to understand whether transcriptional factors are involved in this transition. KEY RESULTS: The callus formed on nascent leaves and subsequently developed the shoot pro-meristem and shoot meristem, thus completing indirect de novo shoot organogenesis in C. richardii. Genes were differentially expressed during the callus transition from proliferation to differentiation, indicating a role for photosynthesis, stimulus response and transmembrane signalling in this transition and the involvement of almost all cell layers that make up the callus. Transcriptional factors were either downregulated or upregulated, which were generally in many-to-many orthology with genes known to be involved in callus development in flowering plants, suggesting that the genetics of fern callus development are both conserved and divergent. Among them, an STM-like, a PLT-like and an ethylene- and salt-inducible ERF gene3-like gene were expressed simultaneously in the vasculature but not in the other parts of the callus, indicating that the vasculature played a role in the callus transition from proliferation to differentiation. CONCLUSIONS: Indirect de novo shoot organogenesis could occur in ferns, and the callus transition from proliferation to differentiation required physiological changes, differential expression of transcriptional factors and involvement of the vasculature.
Ferns , Ferns/genetics , Transcription Factors/genetics , Phylogeny , Meristem , RNA
As a typical spinel oxide, nickel cobaltite (NiCo2O4) is considered to be a promising and reliable oxygen evolution reaction (OER) catalyst due to its abundant oxidation states and the synergistic effect of multiple metal species. However, the electrocatalytic OER performance of NiCo2O4 has always been limited by the low specific surface area and poor intrinsic conductivity of spinels. Herein, the hedgehog-like molybdenum-doped NiCo2O4 (Mo-NiCo2O4) catalyst was prepared as an efficient OER electrocatalyst via a facile hydrothermal method followed with high-temperature annealing. The Mo-NiCo2O4-0.075 with Mo doping concentration of â¼ 1.95 wt% exhibits excellent OER performance with a low overpotential of 265 mV at a current density of 10 mA·cm-2and a Tafel slope of 126.63 mV·dec-1, as well as excellent cyclingstability.The results demonstrated that the hedgehog-like structure provides Mo-NiCo2O4 with the high surface area and mesopores that enhance electrolyte diffusion and optimal active site exposure. The in-situ Raman spectra and density functional theory calculations show that the Mo cations doping improve the intrinsic conductivity of the NiCo2O4 while modulating the chemisorption of intermediates. Meanwhile, the energy barriers of *OH and O* formation decrease significantly after Mo doping, effectively facilitating water dissociation and optimizing the reaction kinetics.
Pyrazinoquinoxaline-based graphdiyne (PQ-GDY) contains a fixed number of sp-sp2 hybridized carbon atoms and pyrazine-like sp2 hybridized N atoms. In this paper, NH2-UIO-66(Zr) on PQ-GDY substrate was successfully constructed with the help of microwave-assisted heating. PQ-GDY surface acts as a microwave antenna under microwave irradiation to rapidly absorb microwave energy and form hot spots (hot spot effect), which facilitates the formation of well-dispersed NH2-UIO-66(Zr) with good crystallinity. Transient absorption spectra show that high hole transport property of PQ-GDY can accelerate the migration of photogenerated holes from NH2-UIO-66(Zr) to PQ-GDY and greatly reduce the recombination rate of photogenerated electrons and holes due to the strong interaction between PQ-GDY and NH2-UIO-66(Zr). Under visible light (λ ≥ 420 nm), PQ-GDY@NH2-UIO-66(Zr) shows high photocatalytic stability and high NOx removal rate up to 74%, which is 44% higher than that of primitive NH2-UIO-66(Zr). At the same time, it inhibits the formation of toxic by-products (NO2) and limits its concentration to a low level.
Microwaves , Phthalic Acids , Light , Carbon
The electrocatalytic nitrogen reduction reaction (NRR) to ammonia is a promising technology to store renewable energy and mitigate greenhouse gas emissions. However, it usually suffers from low ammonia yield and selectivity because of the lack of efficient electrocatalysts. Herein, we report that the construction of metal phosphide heterojunctions is an efficient strategy for NRR activity enhancement. A CoP-MoP heterojunction electrocatalyst, which is fabricated by a facile NaCl template-assisted strategy, exhibits a favorable ammonia yield rate of 77.8 µg h-1 mgcat-1 (38.9 µg h-1 cm-2) and a high faradaic efficiency of 11.16% at -0.50 V versus the reversible hydrogen electrode. The high NRR electrocatalytic activity can be attributed to the electronic coupling effects and interfacial synergistic effects of CoP and MoP at the heterojunction interface, which accelerates the electron transfer rate. Moreover, Mo doping changes the d-band centers of metal sites on the CoP surface, which is conducive to N2 adsorption and promotes N2* adsorption in the competition of occupying active sites, thus inhibiting the HER. This work manifests the high potential of phosphide electrocatalysts and opens an alternative route toward NRR electrocatalysis.
How to mildly structure a high intrinsic activity and stable catalytic electrode to realize long-term catalytic water splitting to produce hydrogen at a wide range of pH values at industrial high current is a challenge. Herein, this work creatively proposes to prepare industrial-grade catalytic electrodes with high efficiency and stability at high current density through carbon quantum dots (CDs) modification nickel sulfide on hydrophilic flexible filter paper via one-step mild chemical plating (denoted as CDs-Ni3 S2 @HFP). The intrinsic activity and surface area, electron transfer ability, and corrosion resistance of Ni3 S2 material are increased due to the regulation, homogenous, and high concentration doping of CDs. The overpotential of the flexible catalytic electrode is only 30, 35, and 87 mV in 1 m KOH, simulated seawater (1 m KOH + 0.5 m NaCl), and neutral electrolyte (0.5 m PBS) at a current density of 10 mA cm-2 . More attractively, the CDs-Ni3 S2 @HFP electrode achieves over 500 h of efficient and stable catalysis at industrial high current density (500 mA cm-2 ). Due to the advantages of mild, universal, and large-area preparation of catalytic materials, this work provides technical support for flexible catalytic electrodes in efficient catalysis toward water splitting, energy storage, and device preparation.
Efficient utilization of infrared (IR) light, which occupies almost half of the solar energy, is an important but challenging task in solar-to-fuel transformation. Herein, we report the discovery of CuS@ZnS core@shell nanocrystals (CSNCs) with strong localized surface plasmon resonance (LSPR) characteristics in the IR light region showing enhanced photocatalytic activity in hydrogen evolution reaction (HER). A unique "plasmon-induced defect-mediated carrier transfer" (PIDCT) at the heterointerfaces of the CSNCs divulged by time-resolved transient spectroscopy enables producing a high quantum yield of 29.2%. The CuS@ZnS CSNCs exhibit high activity and stability in H2 evolution under near-IR light irradiation. The HER rate of CuS@ZnS CSNCs at 26.9 µmol h-1 g-1 is significantly higher than those of CuS NCs (0.4 µmol h-1 g-1) and CuS/ZnS core/satellite heterostructured NCs (15.6 µmol h-1 g-1). The PIDCT may provide a viable strategy for the tuning of LSPR-generated carrier kinetics through controlling the defect engineering to improve photocatalytic performance.
The selective conversion of dilute NO pollutant into low-toxic product and simultaneous storage of metabolic nitrogen for crop plants remains a great challenge from the perspective of waste management and sustainable chemistry. This study demonstrates that this bottleneck can be well tackled by refining the reactive oxygen species (ROS) on Ni-modified NH2 -UiO-66(Zr) (Ni@NU) using nickel foam (NF) as a three-dimensional (3D) substrate through a flow photoanode reactor via the gas-phase photoelectrocatalysis. By rationally refining the ROS to â OH, Ni@NU/NF can rapidly eliminate 82 % of NO without releasing remarkable NO2 under a low bias voltage (0.3â V) and visible light irradiation. The abundant mesoporous pores on Ni@NU/NF are conducive to the diffusion and storage of the formed nitrate, which enables the progressive conversion NO into nitrate with selectivity over 99 % for long-term use. Through calculation, 90 % of NO could be recovered as the nitrate species, indicating that this state-of-the-art strategy can capture, enrich and recycle the pollutant N source from the atmosphere. This study offers a new perspective of NO pollutant treatment and sustainable nitrogen exploitation, which may possess great potential to the development of highly efficient air purification systems for industrial and indoor NOx control.
Aflatoxin B1 (AFB1) is a highly toxic mycotoxin produced by aspergillus species under specific conditions as secondary metabolites. In this study, types of PCL (Polycaprolactone) membranes anchored (or not) to g-C3N4/CQDs composites were prepared using electrospinning technology with (or without) the following surface modification treatment to remove AFB1. These membranes and g-C3N4/CQDs composites were characterized by SEM, TEM, UV-vis, XRD, XPS and FTIR to analyze their physical and chemical properties. Among them, the modified PCL-g-C3N4/CQDs electrospun membranes exhibited an excellent ability to degrade AFB1 via synergistic effects of adsorption and photocatalysis, and the degradation rate of 0.5 µg/mL AFB1 solution was observed to be up to 96.88% in 30 min under visible light irradiation. Moreover, the modified PCL-g-C3N4/CQDs electrospun membranes could be removed directly after the reaction process without centrifugal or magnetic separation, and the regeneration was a green approach synchronized with the reaction under visible light avoiding physical or chemical treatment. The mechanism of adsorption by electrostatic attraction and hydrogen bonding interaction was revealed and the mechanism of photodegradation of AFB1 was also proposed based on active species trapping experiments. This study illuminated the highly synergic adsorption and photocatalytic AFB1 removal efficiency without side effects from the modified PCL-g-C3N4/CQDs electrospun membranes, thereby offering a continual and green solution to AFB1 removal in practical application.
Light , Adsorption , Catalysis , Photolysis
The molecular imprinting technique has aroused great interest in preparing novel stationary phases, and the resulting materials named molecularly imprinted polymers coated silica packing materials exhibit good performance in separating diverse analytes based on their good characteristics (including high selectivity, simple synthesis, and good chemical stability). To date, mono-template is commonly used in synthesizing molecularly imprinted polymers-based stationary phases. The resulting materials always own the disadvantages of low column efficiency and restricted analytes, and the price of ginsenosides with high purity was very high. In this study, to overcome the weaknesses of molecularly imprinted polymers-based stationary phases mentioned above, the multi-templates (total saponins of folium ginseng) strategy was used to prepare ginsenosides imprinted polymer-based stationary phase. The resulting ginsenosides imprinted polymer-coated silica stationary phase has a good spherical shape and suitable pore structures. Additionally, the total saponins of folium ginseng were cheaper than other kinds of ginsenosides. Moreover, the ginsenosides imprinted polymer-coated silica stationary phase-packed column performed well in the separation of ginsenosides, nucleosides, and sulfonamides. The ginsenosides imprinted polymer-coated silica stationary phase possesses good reproducibility, repeatability, and stability for seven days. Therefore, a multi-templates strategy for synthesizing the ginsenosides imprinted polymer-coated silica stationary phase is considered in the future.
Ginsenosides , Saponins , Ginsenosides/chemistry , Polymers/chemistry , Molecularly Imprinted Polymers , Reproducibility of Results , Chromatography, High Pressure Liquid/methods , Silicon Dioxide/chemistry
The degradation of aflatoxin (AF) is a topic that always exists along with the food and feed industry. Photocatalytic degradation as an advanced oxidation technology has many benefits, including complete inorganic degradation, no secondary contamination, ease of activity under moderate conditions, and low cost compared with traditional physical, chemical, and biological strategies. However, photocatalysts are usually dispersed during photocatalytic reactions, resulting in energy and time consumption in the separation process. There is even a potential secondary pollution problem from the perspective of food safety. In this regard, three electrospun membranes anchored with g-C3N4/MoS2 composites were prepared for highly efficient photocatalytic degradation of aflatoxin B1 (AFB1) under visible light. These photocatalytic membranes were characterized by XRD, SEM, TEM, FTIR, and XPS. The factors influencing the degradation efficiency of AFB1, including pH values and initial concentrations, were also probed. The three kinds of photocatalytic membranes all exhibited excellent ability to degrade AFB1. Among them, the photocatalytic degradation efficiency of the photocatalytic membranes prepared by the coaxial methods reached 96.8%. The experiment is with an initial concentration of 0.5 µg/mL (500 PPb) after 60 min under visible light irradiation. The mechanism of degradation of AFB1 was also proposed based on active species trapping experiments. Moreover, the prepared photocatalytic membranes exhibited excellent photocatalytic activity even after five-fold use in the degradation of AFB1. These studies showed that electrospun membranes anchored with g-C3N4/MoS2 composites have a high photocatalytic ability which is easily removed from the reacted medium for reuse. Thereby, our study offers a highly effective, economical, and green solution for AFB1 degradation in the foodstuff for practical application.
Aflatoxin B1 , Molybdenum , Catalysis , Light , Oxidation-Reduction
The abuse and residues of antibiotics have a great impact on the environment and organisms, and their determination has become very important. Due to their low contents, varieties and complex matrices, effective recognition, separation and enrichment are usually required prior to determination. Molecularly imprinted polymers (MIPs), a kind of highly selective polymer prepared via molecular imprinting technology (MIT), are used widely in the analytical detection of antibiotics, as adsorbents of solid-phase extraction (SPE) and as recognition elements of sensors. Herein, recent advances in MIPs for antibiotic residue analysis are reviewed. Firstly, several new preparation techniques of MIPs for detecting antibiotics are briefly introduced, including surface imprinting, nanoimprinting, living/controlled radical polymerization, and multi-template imprinting, multi-functional monomer imprinting and dummy template imprinting. Secondly, several SPE modes based on MIPs are summarized, namely packed SPE, magnetic SPE, dispersive SPE, matrix solid-phase dispersive extraction, solid-phase microextraction, stir-bar sorptive extraction and pipette-tip SPE. Thirdly, the basic principles of MIP-based sensors and three sensing modes, including electrochemical sensing, optical sensing and mass sensing, are also outlined. Fourthly, the research progress on molecularly imprinted SPEs (MISPEs) and MIP-based electrochemical/optical/mass sensors for the detection of various antibiotic residues in environmental and food samples since 2018 are comprehensively reviewed, including sulfonamides, quinolones, ß-lactams and so on. Finally, the preparation and application prospects of MIPs for detecting antibiotics are outlined.
Molecular Imprinting , Molecularly Imprinted Polymers , Anti-Bacterial Agents , Solid Phase Extraction/methods , Solid Phase Microextraction/methods , Polymers/chemistry , Molecular Imprinting/methods
Photoelectrochemical (PEC) activation of chloride ions (Cl-) to degrade persistent organic pollutants (POPs) is a promising strategy for the treatment of industrial saline organic wastewater. However, the wide application of this technology is greatly restricted due to the general photoanode activation of Cl- with poor capability, the propensity to produce toxic by-products chlorates, and the narrow pH range. Herein, oxygen vacancies-enriched titanium dioxide (Ov-TiO2) photoanode is explored to strongly activate Cl- to drive the deep mineralization of POPs wastewater in a wide pH range (2-12) with simultaneous production of H2. More importantly, nearly no toxic by-product of chlorates was produced during such PEC-Cl system. The degradation efficiency of 4-CP and H2 generation rate by Ov-TiO2 were 99.9% within 60 min and 198.2 µmol h-1 cm-2, respectively, which are far superior to that on the TiO2 (33.1% within 60 min, 27.5 µmol h-1 cm-2) working electrode. DFT calculation and capture experiments revealed that Ov-TiO2 with abundant oxygen vacancies is conducive to the activation of Cl- to produce more reactive chlorine species, evidenced by its high production of free chlorine (48.7 mg L-1 vs 7.5 mg L-1 of TiO2). The as-designed PEC-Cl system in this work is expected to realize the purification of industrial saline organic wastewater coupling with green energy H2 evolution.
Chlorides , Persistent Organic Pollutants , Chlorates , Chlorine , Oxygen , Wastewater , Halogens
Designing nonprecious metal-based electrocatalysts to yield sustainable hydrogen energy by large-scale seawater electrolysis is challenging to global emissions of carbon neutrality and carbon peaking. Herein, a series of highly efficient, economical, and robust Ni-P-based nanoballs grown on the flexible and anti-corrosive hydrophobic asbestos (NiPx @HA) is synthesized by electroless plating at 25 °C toward alkaline simulated seawater splitting. On the basis of the strong chemical attachment between 2D layered substrate and nickel-rich components, robust hexagonal Ni5 P4 crystalline modification, and fast electron transfer capability, the overpotentials during hydrogen/oxygen evolution reaction (HER/OER) are 208 and 392 mV at 200 mA cm-2 , and the chronopotentiometric measurement at 500 mA cm-2 lasts for over 40 days. Additionally, the versatile strategy is broadly profitable for industrial applications and enables multi-elemental doping (iron/cobalt/molybdenum/boron/tungsten), flexible substrate employment (nickel foam/filter paper/hydrophilic cloth), and scalable synthesis (22 cm × 22 cm). Density functional theory (DFT) also reveals that the optimized performance is due to the fundamental effect of incorporating O-source into Ni5 P4 . Therefore, this work exhibits a complementary strategy in the construction of NiPx -based electrodes and offers bright opportunities to produce scalable hydrogen effectively and stably in alkaline corrosive electrolytes.
The development of formaldehyde (HCHO) gas sensors with high sensitivity, good selectivity, and fast response at room temperature is an important research topic. The resonant microcantilever, with high sensitivity, easy batch manufacturing, and integration, generates sensing signals based on the relationship between the frequency and the mass addition of the adsorbed molecules and shows good application potential in HCHO detection. Herein, we report two species of MoS2 nanosheets (NSs) with 1T and 2H phases as sensitive materials to construct high-performance HCHO resonant cantilever sensors. The 2H-MoS2 gas sensors show better sensitivity toward HCHO compared to the 1T-MoS2 gas sensor. Specifically, the 2H-MoS2 sensor displayed a high sensitivity (Hz) of 13.6-1 ppm HCHO at room temperature, with high selectivity, low limit of detection (10 ppb), and good humidity resistance. The effect of phase structures on the sensing performance was studied by in situ characterizations, thermodynamic analysis, and density functional theory calculations. The good sensing ability could be attributed to the abundant active sites induced by the surface defects, suitable adsorption strength, and the outstanding thermodynamic performance of the 2H-MoS2. The combination of two-dimensional (2D) nanosheet and microcantilever sensors provides a new direction for developing a high-performance room-temperature gas sensor in the future.
With the development of internet of things and artificial intelligence electronics, metal oxide semiconductor (MOS)-based sensing materials have attracted increasing attention from both fundamental research and practical applications. MOS materials possess intrinsic physicochemical properties, tunable compositions, and electronic structure, and are particularly suitable for integration and miniaturization in developing chemiresistive gas sensors. During sensing processes, the dynamic gas-solid interface interactions play crucial roles in improving sensors' performance, and most studies emphasize the gas-MOS chemical reactions. Herein, from a new view angle focusing more on physical gas-solid interactions during gas sensing, basic theory overview and latest progress for the dynamic process of gas molecules including adsorption, desorption, and diffusion, are systematically summarized and elucidated. The unique electronic sensing mechanisms are also discussed from various aspects including molecular interaction models, gas diffusion mechanism, and interfacial reaction behaviors, where structure-activity relationship and diffusion behavior are overviewed in detail. Especially, the surface adsorption-desorption dynamics are discussed and evaluated, and their potential effects on sensing performance are elucidated from the gas-solid interfacial regulation perspective. Finally, the prospect for further research directions in improving gas dynamic processes in MOS gas sensors is discussed, aiming to supplement the approaches for the development of high-performance MOS gas sensors.
Lycophytes are the earliest vascular plants and Selaginella is the most studied genus among them. Prostrate shoots are produced during early growth and erect shoots emerge later in S. nipponica, thus providing an opportunity for exploring the evolution of the mechanism underlying the transition between growth phases. Six libraries were sequenced for the prostrate and the erect shoots, and a total of 206 768 genes were identified. Some genes were differentially expressed in prostate and erect shoot, with relatively high expression in the prostate shoots being related to hormone responses and defence reactions, while higher expression in the erect shoots was related to spore formation and shoot development. Some SPL genes possessed a miR156 binding site and were highly expressed in the erect shoots, while AP2-like genes were more highly expressed in the prostrate shoots but simultaneously lacked any miR172 binding site. MiR156 was detected at a higher concentration in the prostrate shoots. Thus, the mechanism for the vegetative to reproductive transition of sporophytes probably originated in the common ancestor of vascular plants and must have experienced stepwise development during evolution.
