Biological nitrogen fixation(BNF)and photosynthetic carbon fixation underpin food production and climate mitigation,yet natural systems are constrained by oxygen sensitivity,high energy demand,and inefficient catalyst...Biological nitrogen fixation(BNF)and photosynthetic carbon fixation underpin food production and climate mitigation,yet natural systems are constrained by oxygen sensitivity,high energy demand,and inefficient catalysts.This review synthesizes advances that recast these processes as engineering targets and proposes a conceptual roadmap that bridges synthetic symbioses with the synthetic biology of enzymes and pathways.For BNF,progress spans cross-kingdom strategies—from refactoring nif gene sets and targeting nitrogenase assembly to eukaryotic organelles,to engineering plant-associated diazotrophs,rhizosphere control circuits,and emerging nodule-like microenvironments.For carbon assimilation,new-to-nature CO_(2)-fixation modules and photorespiratory bypasses illustrate how pathway redesign and alternative carboxylases can circumvent key Calvin–Benson–Bassham limitations,and expanding photosynthetic light capture offers additional leverage.Across these domains,we extract common design principles:(i)nitrogenase output is increasingly governed by carbon/energy supply and electron delivery as much as by oxygen protection;(ii)robust function requires compartment-aware enzyme–chassis coordination,substrate channeling,and dynamic regulation using sensors and control circuits;and(iii)scalable implementation may benefit from distributing metabolic labor across engineered consortia rather than forcing all functions into a single host.We discuss enabling technologies—including AI-guided protein design and directed evolution,cell-free prototyping,chassis toolkits,and materials/bioelectrochemical interfaces—that can accelerate design–build–test–learn cycles and reduce barriers to deployment.Together,these insights define a path toward integrated nitrogen and carbon fixation systems for low-emission agriculture and biomanufacturing.展开更多
Nitrogen is essential for plant growth and development,with the ratio of ammonium(NH_(4)^(+))to nitrate(NO_(3)^(-))critically influencing physiological efficiency.This study investigated the effects of different NH_(4...Nitrogen is essential for plant growth and development,with the ratio of ammonium(NH_(4)^(+))to nitrate(NO_(3)^(-))critically influencing physiological efficiency.This study investigated the effects of different NH_(4)^(+)-N/NO_(3)^(-)-N mass ratios(0︰1,3︰7,1︰1,7︰3,1︰0)and a no-nitrogen control on Zanthoxylum planispinum var.dintanensis seedlings,using NH_(4)Cl and NaNO_(3) as nitrogen sources.Key results revealed that a 3︰7 NH_(4)^(+)︰NO_(3)^(-)ratio(T2)significantly enhanced stomatal conductance(G_(s)),amino acid content,root tip number,and the photochemical quenching parameters q_(P),q_(L),ETR,and F_(v)/F_(m).This treatment also maximized ground diameter increment,chlorophyll content,intercellular CO_(2)concentration(C_(i)),transpiration rate(T_(r)),ribulose-1,5-bisphosphate carboxylase(Rubisco)activity,nitrate reductase(NR)activity,and soluble protein content.Conversely,a 7︰3 ratio(T4)yielded the highest net photosynthetic rate(Pn)and fructose-1,6-bisphosphate aldolase(FBA)activity.Overall,the T4 treatment exhibited the second most effective promotion of Z.planispinum var.dintanensis seedling growth and development,after T2.In summary,mixed NH_(4)^(+)-N/NO_(3)^(-)-N nutrition markedly enhances seedling performance,with the 3︰7 ratio optimal for growth,photosynthesis,and nitrogen assimilation.Sole nitrogen sources,particularly pure NH_(4)^(+)-N,exert inhibitory effects.展开更多
A collection of ordered-disordered Bi_(2)WO_(6)homojunction catalysts was prepared in-situ through a facile one-step hydrothermal process,and their photocatalytic nitrogen fixation to synthesize ammonia performance wa...A collection of ordered-disordered Bi_(2)WO_(6)homojunction catalysts was prepared in-situ through a facile one-step hydrothermal process,and their photocatalytic nitrogen fixation to synthesize ammonia performance was evaluated.Results showed that ordered-disordered Bi_(2)WO_(6)(OD-2)obtained by adding 1.5 mL of ethylene glycol during preparation exhibited the optimal nitrogen fixation performance,with a nitrogen fixation rate of 114.92μmol·g^(-1)·h^(-1).However,its crystal counterpart,Bi_(2)WO_(6)(BWO),lacked nitrogen-fixation activity.In-situ diffuse reflectance-Fourier transform infrared technique(DR-FTIR),electrochemical tests,and energy band structure analysis confirmed that the surface disordered structure in OD-2 not only promoted nitrogen activation but also enabled the effective separation of photogenerated electron-hole pairs at the ordered-disordered interface,facilitating the interface electrons transfer to the surface disordered structure of OD-2 and reacting with N_(2) adsorbed on the disordered structure,thereby promoting the smooth progress of the nitrogen fixation reaction.展开更多
Chlorophyll-a is the most abundant chlorophyll pigment produced by marine phytoplankton,and it bears the isotope signature of the nitrate source assimilated in the N-atoms that are embedded in its porphyrin ring.The c...Chlorophyll-a is the most abundant chlorophyll pigment produced by marine phytoplankton,and it bears the isotope signature of the nitrate source assimilated in the N-atoms that are embedded in its porphyrin ring.The chloropigment and its degradation product,i.e.,pheophytin-a,could be well preserved in marine sediment,usually at nanomolar level.A sensitive and accurate measurement of theδ15N of chloropigment is capable of providing rich information to greatly enhance our understanding of past nitrogen cycling,which therefore is urgently needed.Hereby,we present a successful method based on two-step HPLC separation followed by'denitrifier method'.The N-content in acetone and potassium persulfate(K_(2)S_(2)O_(8))are very critical to the precision and accuracy of the measurements,because they constitute the majority of the N contamination to the Chl-a samples.In this method,the recrystallized K_(2)S_(2)O_(8)that is used as oxidization reagent was discovered to have aδ15N background of-15‰,consolidated by repeated examinations over a period of two months.This 15N background of K_(2)S_(2)O_(8)would cause-1‰–-2‰deviation on theδ^(15)N of sample that contains nanomolar level N,and highlight the need to examine theδ^(15)N of recrystallized K_(2)S_(2)O_(8)when it is used to oxidize samples of organic nitrogen.The overall measurement ofδ^(15)N pigment is reliable and has an average analytical precision better than±0.5‰(1σ).This study establish a sensitive method for accurate measurement of theδ^(15)N of nano-molar level chlorophyll pigment,and with no doubts will advance its wide application in marine nitrogen cycling studying.展开更多
Lodging is a primary factor limiting rice grain yield.Achieving synergistic improvements in grain yield and nitrogen use efficiency(NUE)without increasing lodging risk has been a global research priority.In this study...Lodging is a primary factor limiting rice grain yield.Achieving synergistic improvements in grain yield and nitrogen use efficiency(NUE)without increasing lodging risk has been a global research priority.In this study,two rice cultivars-Yongyou 2640(indica–japonica hybrid rice)and Jinxiangyu 1(inbred japonica rice)-were evaluated in field experiments conducted over two growing seasons.Six nitrogen management strategies were implemented:no nitrogen(T1),conventional urea(T2),controlled-release nitrogen(CRN)(T3),reduction of CRN(T4),CRN combined with single basal application of conventional urea(T5),and CRN combined with split applications of conventional urea(T6).Compared with T2,the integrated nitrogen strategies(T5 and T6)increased NUE by 4.89–5.69%and grain yield by 3.41–4.65%.These treatments also enhanced structural integrity of the second basal internode,evidenced by increased carbohydrate content,internode breaking strength,epidermal silicon layer thickness,number of large and small vascular bundles,and thickness of both parenchymatous and mechanical tissues.Concurrently,internode length,bending moment,and lodging index were reduced.Collectively,these findings indicate that integrating CRN with conventional urea improves morphological,mechanical,physicochemical,and anatomical properties of the second basal internode,thereby enhancing stem strength and enabling high yield and NUE without compromising lodging resistance.展开更多
A novel salt-tolerant aerobic denitrifying bacterium,Marinobacter sp.strain B108,was isolated from a marine recirculating aquaculture system(MRAS).The optimal aerobic denitrification parameters were CH_(3)COONa as car...A novel salt-tolerant aerobic denitrifying bacterium,Marinobacter sp.strain B108,was isolated from a marine recirculating aquaculture system(MRAS).The optimal aerobic denitrification parameters were CH_(3)COONa as carbon source,pH of 8,C/N of16,temperature of 35°C,dissolved oxygen(DO)of 6 mg/L and salinity of 30.Under these optimal conditions,Marinobacter sp.strain B108 had a removal efficiency of 100%for N O_(3)^(-)-N and 98.89%for total nitrogen(TN)within 24 h.The nitrate removal pathways of Marinobacter sp.strain B108 were included by the assimilative reduction pathway(N O_(3)^(-)-N→biomass N)and the dissimilatory reduction pathway(N O_(3)^(-)-N→N_(2))of aerobic denitrification,and lack of dissimilatory reduction to ammonium pathway(N O_(3)^(-)-N→N H_(4)^(+)-N).The nitrogen removal process of Marinobacter sp.strain B108 was mainly contributed by the dissimilatory reduction pathway.The kinetic parameters for N O_(3)^(-)-N and N O_(2)^(-)-N removal were determined as V_(m)of 971.566 and 165.336 mg/(gDCW·L·h),and K_(m)of 22.74 and 31.68 mg/L,respectively.This work reflects the practical application potential of Marinobacter sp.strain B108for nitrogen removal in MRAS.展开更多
Amid accelerating global land degradation,establishing high-efficiency ecological restoration principles and frameworks is crucial.Here,we explore the application of threshold effects in the ecological restoration pro...Amid accelerating global land degradation,establishing high-efficiency ecological restoration principles and frameworks is crucial.Here,we explore the application of threshold effects in the ecological restoration process based on field experiments and globally available experimental data from 173 sites.Combining data integration analysis and meta-analysis,we collectively verified the universality of threshold effects in grasslands.The global grasslands’average nitrogen application threshold is 3.78 g·m^(-2)·yr^(−1),while the threshold value of degraded grassland(3.65 g·m^(-2)·yr^(−1))is lower than that of nondegraded grassland(5.90 g·m^(-2)·yr^(−1)).The low nitrogen-driven thresholds are affected by degradation status,climate(precipitation and temperature),and other site conditions,but not fertilization forms.Independent experiments further demonstrated that an increase in soil moisture content can lead to the disappearance of nitrogen threshold effects,revealing that ecological threshold effects are influenced by ecosystem stress factors.Following the significant increase in plant biomass triggered by the nitrogen threshold,the ecosystem undergoes systemic improvement.Soil organic carbon,urease activity,soil microbial diversity,and other soil properties are significantly enhanced.Soil nitrogen cycle-related microbial communities and soil physicochemical attributes are significantly activated.The results indicate that a threshold response pattern may develop before nitrogen saturation is reached,and low nitrogen input can boost productivity and improve the plant-soil-microbe system.Our findings reveal a nonprogressive path of restoration in degraded ecosystems,and thus,restoration based on threshold effects can offer an efficient and safe solution to combat ecological degradation.展开更多
The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited im...The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited imaginary frequencies in their phonon spectra at 0 GPa.Here,we conducted a systematic investigation of P-N compounds using first-principles calculations,uncovering a series of structurally similar stable phases,C2/m-PN_(x)(x=6,8,10,12,and 14),in which N forms zigzag N chains similar to those in Ch-N.In P-N compounds,the longest zigzag N-chain,which can theoretically remain stable under ambient pressure,is the N-chain composed of 14 N atoms in C2/m-PN14.If the N-chain continues to grow,imaginary interchain vibrational frequencies arise in the system.Notably,N chains with an even number of atoms were more likely to be energetically favorable.The five C2/m-PN_(x) phases and one metastable phase(R-PN_(6))exhibited remarkable stability and excellent detonability at ambient pressure,indicating that they are promising candidates for high-energy-density materials.In addition,R-PN_(6) was the first structure to stabilize the N_(6) ring through covalent bonding,with the covalent network contributing to its high hardness(47.59 GPa).展开更多
Photocatalytic nitrogen fixation (PNF) is a promising alternative to the Haber-Bosch process.It achieves green ammonia production by utilizing solar energy for nitrogen fixation under mild conditions.While nanoscale p...Photocatalytic nitrogen fixation (PNF) is a promising alternative to the Haber-Bosch process.It achieves green ammonia production by utilizing solar energy for nitrogen fixation under mild conditions.While nanoscale photocatalysts offer enhanced performance due to their high surface area and abundant active sites,their small size makes them difficult to recover and prone to agglomeration.These bottlenecks severely limit industrial application.A promising solution is to immobilize the catalysts onto support surfaces.This paper provides a systematic review of recent advances in the design of immobilized photocatalysts for ammonia synthesis.It begins by outlining the key benefits of immobilization strategies,particularly in improving catalyst stability,recyclability,and overall photocatalytic performance.The working mechanisms and features of various immobilization techniques are then categorized and explained,covering physical adsorption/deposition,chemical bonding,in situ growth,and hybrid physico-chemical methods.Supported materials and common substrate types are also summarized.Furthermore,the widely used configurations of photoreactors suitable for immobilized systems are introduced.Finally,the review identifies current research limitations and challenges,and offers perspectives on future developments in the field of immobilized photocatalysis.展开更多
Using unscientific agricultural methods can harm human health by increasing harmful nitrate(NO_(3)−)levels in groundwater,as observed in the Yinchuan Plain.This research utilized hydrochemical data,dual isotopic data,...Using unscientific agricultural methods can harm human health by increasing harmful nitrate(NO_(3)−)levels in groundwater,as observed in the Yinchuan Plain.This research utilized hydrochemical data,dual isotopic data,the MixSIAR model,and the uncertainty index(UI90)to detect the potential sources of groundwater NO_(3)−,track NO_(3)−conversion processes,and calculate the apportionment of each groundwater NO_(3)−source in the agricultural lands of the Yinchuan Plain.The results show that soil organic nitrogen accounted for 49.4%,and N-fertilizers contributed 30.4%,making them the two main contributors to NO_(3)-contamination in groundwater.Long-term N-fertilization enhances soil organic nitrogen accumulation,resulting in NO_(3)−leaching into groundwater during irrigation.The highest uncertainty regarding soil organic nitrogen and N-fertilizers may stem from changes in groundwater flow patterns,unbalanced N-fertilization,irrigation,and precipitation.Denitrification is the dominant process,resulting in lower NO_(3)−concentrations in groundwater in most areas.As a result,most groundwater in the Yinchuan Plain is generally safe for human consumption,except the specific areas in Qingtongxia City and Wuzhong City.Flood irrigation can increase the leaching of NO_(3)−into groundwater,and the repeated recharge of groundwater contaminated with high NO_(3)−levels could also be a potential source of NO_(3)−contamination in agricultural areas.This research provides scientific guidance for sustainable groundwater management in the Yinchuan Plain,mitigating the risk of groundwater NO_(3)−pollution.展开更多
Ecological floating bed is an important biological remediation method for water pollution control.During the removal of excess nutrients and pollutants,changes in environmental factors affect the characteristics of mi...Ecological floating bed is an important biological remediation method for water pollution control.During the removal of excess nutrients and pollutants,changes in environmental factors affect the characteristics of microorganisms in aquatic ecosystems.To understand the influences of ecological floating beds on size-fractionated microorganisms,we investigated the community assembly and nitrogen metabolic characteristics of three size-fractionated microorganism groups in the ecological floating bed area,using 18S rDNA,16S rDNA metabarcoding,and metagenomic sequencing techniques.Firstly,we discovered substantial differences between size-fractionated groups in the diversity and compositions of both microeukaryotic and bacterial communities,as well as the influences of floating beds on specific groups.The floating beds appeared to provide more habitats for heterotrophs and symbiotes while potentially inhibiting the growth of certain phytoplankton(cyanobacteria).Secondly,we observed that microeukaryotic and bacterial communities were predominantly influenced by stochastic and deterministic processes,respectively,and they both exhibited distinct patterns across different size-fractionated groups.Notably,microeukaryotic community assembly demonstrated a greater sensitivity to ecological floating beds,as indicated by an increase in dispersal limitation processes.Finally,the nitrogen metabolism functional genes revealed that microbes associated with large-sized particles played a crucial role in dissimilatory nitrate reduction to ammonium(DNRA)and denitrification processes within the floating bed area,thereby facilitating the removal of excess nitrogen nutrients from the water.In contrast,freeliving microorganisms from small-sized groups were linked mainly to the genes involved in nitrogen assimilation and assimilatory nitrate reduction to ammonium(ANRA)processes.These findings help understand the impact of ecological floating beds on the diversity and functional characteristics of microorganism communities in different size-fractionated groups.展开更多
To explore the adaptive mechanisms of the partial nitritation-anammox(PNA)process under high salinity stress during kitchen wastewater treatment,focusing on their physiological and molecular responses through metageno...To explore the adaptive mechanisms of the partial nitritation-anammox(PNA)process under high salinity stress during kitchen wastewater treatment,focusing on their physiological and molecular responses through metagenomic analysis.An airlift inner-circulation partition bioreactor(AIPBR)was developed,featuring an inner cylinder and a flow guide tube to create distinct oxygen gradients,facilitating the study of microbial adaptation under varying salt conditions.The AIPBR was operated with synthetic wastewater containing ammonium concentrations of 1800±100 mg/L and salinity gradients ranging from 1 to 10 g/L,followed by a fixed salinity period at 6 g/L,with ammonium concentrations approximately 850 mg/L.High-throughput metagenomic analysis revealed shifts in functional genes and metabolic pathways in response to salinity stress.Anammox bacteria adapted by enriching genes involved in the synthesis of osmoprotective compounds and activating energy-producing pathways like the tricarboxylic acid cycle(TCA).These adaptations,along with modifications in membrane composition,were essential for sustaining system stability under elevated salinity.Under prolonged high salinity stress,anaerobic ammonium oxidizing(AnAOB)exhibited improved salt tolerance,maintaining a total nitrogen removal efficiency above 85%and stabilizing after an adaptation phase.The metagenomic data revealed a marked enrichment of genes associated with ion transport,stress response mechanisms,and DNA repair pathways.Changes in microbial community composition favored salt-tolerant species,supporting system stability.These findings highlight the applicability of the developed bioreactor for scaling up the PNA process to handle high-salinity wastewater,providing a promising avenue for sustainable nitrogen removal in challenging environments.展开更多
In order to address the evolving emission characteristics of oxygenated volatile organic compounds(OVOCs),it is essential to develop adsorbent materials specifically designed for the efficient adsorption of OVOCs with...In order to address the evolving emission characteristics of oxygenated volatile organic compounds(OVOCs),it is essential to develop adsorbent materials specifically designed for the efficient adsorption of OVOCs with large kinetic diameters.In this study,we used co-pyrolysis to prepare a series of graded porous carbon materials with well-developed micropores by adjusting the doping ratios of root nodules and pretreated cellulose.The material with root nodule to cellulose mass ratio of 1:1(TCC-RN-1)exhibited the highest saturated adsorption capacity for butyl acetate(834 mg/g).This can be attributed to enhanced pore size distribution from nodule doping,which facilitates the development of a micropore-graded structure.Additionally,the nodules acted as auxiliary activating agents that enhanced the KOH micropore regulation effect during the activation stage,resulting in the highest micropore volume(0.863 cm^(3)/g).The doping of root nodules facilitated the formation of additional defects on the surface of the porous carbon material,leading to a more disordered arrangement that improved pollutant adsorption.Furthermore,TCC-RN-1 demonstrated good thermal stability in an air atmosphere,main-taining a butyl acetate adsorption capacity exceeding 95%after five adsorption-desorption cycles.This indicates its favorable potential for industrial applications.展开更多
[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Provi...[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Province,evaluating various combinations of planting density and nitrogen rate for Chuxue 80.[Results]At the maturity stage,the TN1 treatment(5 kg N per 667 m^(2) with a density of 1900 plants per 667 m^(2))demonstrated the most favorable agronomic performance.The TN9 treatment(11 kg N per 667 m^(2) with a density of 1110 plants per 667 m^(2))achieved the highest wrapper tobacco yield and output value.Meanwhile,the TN5 treatment(8 kg N per 667 m^(2) with a density of 1515 plants per 667 m^(2))resulted in the best smoking quality.[Conclusions]The TN9 treatment,with a planting density of 1110 plants per 667 m^(2) and a nitrogen application rate of 11 kg per 667 m^(2),is recommended as the optimal cultivation practice for Chuxue 80 in Hubei Province.展开更多
Along with decrease of fine particulate matter(PM_(2.5))concentration in recent years in China,secondary species become increasingly important.This work focuses on characterizing secondary components,and a few importa...Along with decrease of fine particulate matter(PM_(2.5))concentration in recent years in China,secondary species become increasingly important.This work focuses on characterizing secondary components,and a few important groups of organics including organic nitrogen(ON),organonitrates(OrgN),organosulfates(OS)and polycyclic aromatic hydrocarbons(PAHs),via online measurement of submicron aerosols(PM_(1))in Nanjing,China,during 2022 summer.The average PM_(1) concentration was 15.39μg/m^(3),dominated by secondary components(69.1%),which were even more important at higher PM_(1) levels.The primary organic aerosols(POA)were from traffic,industry and cooking;the two secondary OA factors were both closely linked with photochemistry,with one(OOA1)being relatively fresh and important in early afternoon and another(OOA2)being aged and important in late afternoon.Sulfate formation was also governed by photochemistry but resembled that of OOA2 not OOA1;nitrate formation was associated strongly with heterogeneous hydrolysis and thermodynamic equilibrium.Results also reveal a possible photochemical reaction channel from POA to OOA1,then to OOA2.Case studies show that formations of secondary components responded differently to different weather conditions and governed summer PM_(1) pollution.The average ON,OrgN,OS and PAHs concentrations were determined to be 122.8,84.4,45.6 and 3.3 ng/m^(3),respectively.ON was dominated by primary sources(53.8%).OrgN varied similarly to nitrate.OS formation was linked with aqueous-phase reactions,which were insignificant therefore its level was low.PAHs was mainly from traffic,and photochemical oxidation might be its important sink during afternoon.展开更多
Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassi...Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassium fertilization interactively influence lignin biosynthesis in oil flax stems require further investigation.Therefore,this study aimed to enhance lodging resistance and increase grain yield in oil flax.We examined the interactive effects of different nitrogen (75,150,and 225 kg N ha^(–1)) and potassium (60 and 90 kg K_(2)O ha^(–1)) fertilizer rates on lignin metabolism,lodging resistance,and grain yield during the 2022 and 2023 growing seasons.Results indicated that nitrogen and potassium fertilizer levels and their interactions promoted lignin accumulation,improved lodging resistance,and increased grain yield.Compared to the control (CK),the75–150 kg N ha^(–1) combined with 60 kg K_(2)O ha^(–1) treatments significantly enhanced the activities of key lignin-synthesizing enzymes (tyrosine ammonia-lyase (TAL),phenylalanine ammonia-lyase (PAL),cinnamyl alcohol dehydrogenase (CAD),and peroxidase (POD)) and upregulated the expression of 4CL1 and F5H3 genes,leading to a 29.63–43.30%increase in lignin content,improved stem bending strength and lodging resistance index,and a 23.27–32.34%increase in grain yield.Correlation analysis revealed that nitrogen and potassium fertilizers positively regulated enzyme activities and gene expression related to lignin biosynthesis,thereby facilitating lignin accumulation and enhancing stem mechanical strength and lodging resistance.Positive correlations were observed among lignin-related enzyme activities,gene expression,lodging resistance traits,and grain yield.In summary,the application of 75–150 kg N ha^(–1) in conjunction with 60 kg K_(2)O ha^(–1)promoted lignin biosynthesis and accumulation,enhanced lodging resistance,and increased grain yield in oil flax grown in the dryland farming region of central Gansu,China.Furthermore,this treatment provides a technical basis for cultivating stress-tolerant and high-yield oil flax in arid regions.展开更多
Nutrients play a crucial role in sustaining marine ecosystems and supporting mariculture,especially in seaweed aquaculture.Currently,seaweed farming,such as kelp cultivation,is entirely dependent on the natural supply...Nutrients play a crucial role in sustaining marine ecosystems and supporting mariculture,especially in seaweed aquaculture.Currently,seaweed farming,such as kelp cultivation,is entirely dependent on the natural supply of nutrients.Sanggou Bay in Shandong Peninsula,Yellow Sea,is renowned for its 60-year history of kelp cultivation;however,it is recently facing an increasing demand for nitrogen and phosphorus due to the expansion in aquaculture scale and production.There is no doubt that nutrient addition can enhance and sustain the production,but it is crucial to understand its effect on kelp growth under current nutrients condition and the potential ecological risks.Our in-field nutrient enrichment experiments show that nitrogen and phosphorus additions promoted the kelp biomass during the early growth stages,and have no adverse effects on phytoplankton or seawater nutrient levels throughout the experiment.From a long-term perspective,increasing nutrient supply appears to be an essential strategy for sustaining the aquaculture of kelp.展开更多
Climate warming and atmospheric nitrogen(N)deposition have profound influences on the terrestrial biosphere.However,how these two global change drivers affect phytoplankton which are important primary producers in wet...Climate warming and atmospheric nitrogen(N)deposition have profound influences on the terrestrial biosphere.However,how these two global change drivers affect phytoplankton which are important primary producers in wetlands with large carbon stocks and complex hydrological fluctuations remain largely unclear.As part of a two-year field experiment in a freshwater wetland,this study was conducted to investigate the effects of nighttime warming and N addition on phytoplankton biomass in the North China Plain.The results showed that neither nighttime warming nor N addition influenced the Shannon-Wiener index of phytoplankton community.Nighttime warming did not change phytoplankton biomass,likely due to the different warming impacts on dominant phyla and in different seasons.Decreased phytoplankton biomass in spring because of the increased water pH and submerged plant coverage was compensated by the enhanced biomass in autumn due to the reduced dissolved oxygen and submerged plant coverage,leading to the neutral change of phytoplankton biomass under warming.Nitrogen addition elevated phytoplankton biomass by 11.6%,which could be attributed to the enhanced nutrient availability and reduced submerged plant coverage.Positive relationships of methane(CH4)emission rates at the water-air interface with phytoplankton biomass indicated the potentially crucial role of phytoplankton in mediating wetland CH4 cycling through photosynthesis-driven metabolisms.The findings suggested the seasonal variation of phytoplankton and their potential responses to nighttime warming and N deposition,which may provide a more accurate basis for assessing the global change-carbon feedback in wetland ecosystems.展开更多
Nitrogen-containing structures represent a significant branch exhibiting remarkable biological activity,surpassing non-nitrogen architectures.Given the vast array of nitrogen-containing compounds and their crucial rol...Nitrogen-containing structures represent a significant branch exhibiting remarkable biological activity,surpassing non-nitrogen architectures.Given the vast array of nitrogen-containing compounds and their crucial role in the pharmaceutical industry,chemists have been motivated to devise efficient,cost-effective,and practical methods for C-N bond formation.Significant advancements have been achieved in this cutting-edge field over the past few decades.This review aims to encapsulate the latest progress in C-N bond formation via the photocatalytic C-H amination process.Initially,we provide a comprehensive introduction to C-H amination transformations.Subsequently,we categorize these photochemical conversions into two parts:intramolecular and intermolecular C-H amination.To elucidate the underlying principles of specific illustrative examples,we have carefully chosen and elaborated on the reaction mechanisms,representative experimental outcomes,and applications.展开更多
Cellulose,the most abundant and renewable biopolymer,offers a sustainable and cost-effective solution for regulating lithium electrodeposition toward safer lithium metal batteries,thanks to its high nanofibrous struct...Cellulose,the most abundant and renewable biopolymer,offers a sustainable and cost-effective solution for regulating lithium electrodeposition toward safer lithium metal batteries,thanks to its high nanofibrous structure and intrinsic lithiophilic property.In this work,we introduce interface-engineered cellulose-based separators by converting intrinsic hydroxyl groups on cellulose nanofibers(CNFs)to nitrogen functionalities through a trace conducting polymer coating.Both experimental and theoretical results reveal that the nitrogen moieties disrupt the compact hydrogen bond network within hydroxyl cellulose,enabling multiple nitrogen-lithium interactions that enhance lithium ion transport.In addition to an extraordinary Li^(+)transference number of 0.86 and a high ionic conductivity of 1.1 mS cm^(-1),the nitrogen-functionalized CNF contributes to a uniform electric field and Li^(+)concentration distribution across the lithium metal surface.This facilitates the formation of a LiF-rich solid electrolyte interface and suppresses Li dendrite growth.Consequently,Li‖Li cells demonstrate stable plating/stripping cycles for approximately 3000 h at a current density of 1 mA cm^(-2) with a fixed capacity of 1 mAh cm^(-2),while maintaining a low overpotential of 15 mV.Our work provides valuable insights into the surface functionalization of natural biomass for advancing sustainable energy storage technologies.展开更多
基金supported by the funds of the Ministry of Science and Technology of China(2019YFA0904700)the National Natural Science Foundation of China(32471477)to Cheng Qi.
文摘Biological nitrogen fixation(BNF)and photosynthetic carbon fixation underpin food production and climate mitigation,yet natural systems are constrained by oxygen sensitivity,high energy demand,and inefficient catalysts.This review synthesizes advances that recast these processes as engineering targets and proposes a conceptual roadmap that bridges synthetic symbioses with the synthetic biology of enzymes and pathways.For BNF,progress spans cross-kingdom strategies—from refactoring nif gene sets and targeting nitrogenase assembly to eukaryotic organelles,to engineering plant-associated diazotrophs,rhizosphere control circuits,and emerging nodule-like microenvironments.For carbon assimilation,new-to-nature CO_(2)-fixation modules and photorespiratory bypasses illustrate how pathway redesign and alternative carboxylases can circumvent key Calvin–Benson–Bassham limitations,and expanding photosynthetic light capture offers additional leverage.Across these domains,we extract common design principles:(i)nitrogenase output is increasingly governed by carbon/energy supply and electron delivery as much as by oxygen protection;(ii)robust function requires compartment-aware enzyme–chassis coordination,substrate channeling,and dynamic regulation using sensors and control circuits;and(iii)scalable implementation may benefit from distributing metabolic labor across engineered consortia rather than forcing all functions into a single host.We discuss enabling technologies—including AI-guided protein design and directed evolution,cell-free prototyping,chassis toolkits,and materials/bioelectrochemical interfaces—that can accelerate design–build–test–learn cycles and reduce barriers to deployment.Together,these insights define a path toward integrated nitrogen and carbon fixation systems for low-emission agriculture and biomanufacturing.
文摘Nitrogen is essential for plant growth and development,with the ratio of ammonium(NH_(4)^(+))to nitrate(NO_(3)^(-))critically influencing physiological efficiency.This study investigated the effects of different NH_(4)^(+)-N/NO_(3)^(-)-N mass ratios(0︰1,3︰7,1︰1,7︰3,1︰0)and a no-nitrogen control on Zanthoxylum planispinum var.dintanensis seedlings,using NH_(4)Cl and NaNO_(3) as nitrogen sources.Key results revealed that a 3︰7 NH_(4)^(+)︰NO_(3)^(-)ratio(T2)significantly enhanced stomatal conductance(G_(s)),amino acid content,root tip number,and the photochemical quenching parameters q_(P),q_(L),ETR,and F_(v)/F_(m).This treatment also maximized ground diameter increment,chlorophyll content,intercellular CO_(2)concentration(C_(i)),transpiration rate(T_(r)),ribulose-1,5-bisphosphate carboxylase(Rubisco)activity,nitrate reductase(NR)activity,and soluble protein content.Conversely,a 7︰3 ratio(T4)yielded the highest net photosynthetic rate(Pn)and fructose-1,6-bisphosphate aldolase(FBA)activity.Overall,the T4 treatment exhibited the second most effective promotion of Z.planispinum var.dintanensis seedling growth and development,after T2.In summary,mixed NH_(4)^(+)-N/NO_(3)^(-)-N nutrition markedly enhances seedling performance,with the 3︰7 ratio optimal for growth,photosynthesis,and nitrogen assimilation.Sole nitrogen sources,particularly pure NH_(4)^(+)-N,exert inhibitory effects.
文摘A collection of ordered-disordered Bi_(2)WO_(6)homojunction catalysts was prepared in-situ through a facile one-step hydrothermal process,and their photocatalytic nitrogen fixation to synthesize ammonia performance was evaluated.Results showed that ordered-disordered Bi_(2)WO_(6)(OD-2)obtained by adding 1.5 mL of ethylene glycol during preparation exhibited the optimal nitrogen fixation performance,with a nitrogen fixation rate of 114.92μmol·g^(-1)·h^(-1).However,its crystal counterpart,Bi_(2)WO_(6)(BWO),lacked nitrogen-fixation activity.In-situ diffuse reflectance-Fourier transform infrared technique(DR-FTIR),electrochemical tests,and energy band structure analysis confirmed that the surface disordered structure in OD-2 not only promoted nitrogen activation but also enabled the effective separation of photogenerated electron-hole pairs at the ordered-disordered interface,facilitating the interface electrons transfer to the surface disordered structure of OD-2 and reacting with N_(2) adsorbed on the disordered structure,thereby promoting the smooth progress of the nitrogen fixation reaction.
基金National Science Foundation of China(No.41576082)。
文摘Chlorophyll-a is the most abundant chlorophyll pigment produced by marine phytoplankton,and it bears the isotope signature of the nitrate source assimilated in the N-atoms that are embedded in its porphyrin ring.The chloropigment and its degradation product,i.e.,pheophytin-a,could be well preserved in marine sediment,usually at nanomolar level.A sensitive and accurate measurement of theδ15N of chloropigment is capable of providing rich information to greatly enhance our understanding of past nitrogen cycling,which therefore is urgently needed.Hereby,we present a successful method based on two-step HPLC separation followed by'denitrifier method'.The N-content in acetone and potassium persulfate(K_(2)S_(2)O_(8))are very critical to the precision and accuracy of the measurements,because they constitute the majority of the N contamination to the Chl-a samples.In this method,the recrystallized K_(2)S_(2)O_(8)that is used as oxidization reagent was discovered to have aδ15N background of-15‰,consolidated by repeated examinations over a period of two months.This 15N background of K_(2)S_(2)O_(8)would cause-1‰–-2‰deviation on theδ^(15)N of sample that contains nanomolar level N,and highlight the need to examine theδ^(15)N of recrystallized K_(2)S_(2)O_(8)when it is used to oxidize samples of organic nitrogen.The overall measurement ofδ^(15)N pigment is reliable and has an average analytical precision better than±0.5‰(1σ).This study establish a sensitive method for accurate measurement of theδ^(15)N of nano-molar level chlorophyll pigment,and with no doubts will advance its wide application in marine nitrogen cycling studying.
基金supported by the National Key Research and Development Program of China(2022YFD2300304)the National Natural Science Foundation of China(32272197 and 32071944)+2 种基金the Hong Kong Research Grants Council,China(GRF 14177617,12103219,12103220,and AoE/M-403/16)the State Key Laboratory of Agrobiotechnology(Strategic Collaborative Projects)at the Chinese University of Hong Kong,Chinathe Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)。
文摘Lodging is a primary factor limiting rice grain yield.Achieving synergistic improvements in grain yield and nitrogen use efficiency(NUE)without increasing lodging risk has been a global research priority.In this study,two rice cultivars-Yongyou 2640(indica–japonica hybrid rice)and Jinxiangyu 1(inbred japonica rice)-were evaluated in field experiments conducted over two growing seasons.Six nitrogen management strategies were implemented:no nitrogen(T1),conventional urea(T2),controlled-release nitrogen(CRN)(T3),reduction of CRN(T4),CRN combined with single basal application of conventional urea(T5),and CRN combined with split applications of conventional urea(T6).Compared with T2,the integrated nitrogen strategies(T5 and T6)increased NUE by 4.89–5.69%and grain yield by 3.41–4.65%.These treatments also enhanced structural integrity of the second basal internode,evidenced by increased carbohydrate content,internode breaking strength,epidermal silicon layer thickness,number of large and small vascular bundles,and thickness of both parenchymatous and mechanical tissues.Concurrently,internode length,bending moment,and lodging index were reduced.Collectively,these findings indicate that integrating CRN with conventional urea improves morphological,mechanical,physicochemical,and anatomical properties of the second basal internode,thereby enhancing stem strength and enabling high yield and NUE without compromising lodging resistance.
基金National Natural Science Foundation of China(No.51978636)。
文摘A novel salt-tolerant aerobic denitrifying bacterium,Marinobacter sp.strain B108,was isolated from a marine recirculating aquaculture system(MRAS).The optimal aerobic denitrification parameters were CH_(3)COONa as carbon source,pH of 8,C/N of16,temperature of 35°C,dissolved oxygen(DO)of 6 mg/L and salinity of 30.Under these optimal conditions,Marinobacter sp.strain B108 had a removal efficiency of 100%for N O_(3)^(-)-N and 98.89%for total nitrogen(TN)within 24 h.The nitrate removal pathways of Marinobacter sp.strain B108 were included by the assimilative reduction pathway(N O_(3)^(-)-N→biomass N)and the dissimilatory reduction pathway(N O_(3)^(-)-N→N_(2))of aerobic denitrification,and lack of dissimilatory reduction to ammonium pathway(N O_(3)^(-)-N→N H_(4)^(+)-N).The nitrogen removal process of Marinobacter sp.strain B108 was mainly contributed by the dissimilatory reduction pathway.The kinetic parameters for N O_(3)^(-)-N and N O_(2)^(-)-N removal were determined as V_(m)of 971.566 and 165.336 mg/(gDCW·L·h),and K_(m)of 22.74 and 31.68 mg/L,respectively.This work reflects the practical application potential of Marinobacter sp.strain B108for nitrogen removal in MRAS.
基金supported by the Major Special Projects of the National Natural Science Foundation of China(Grants No.52374170 and 42377465)the Third Comprehensive Scientific Exploration in Xinjiang(Grant No.2022xjkk1005)+1 种基金the Special Technology Innovation Fund of Carbon Peak and Carbon Neutrality in Jiangsu Province(Grant No.BK20231515)the Shaanxi Shenmu Natural Field Observation and Research Station of Erosion and Environment,which provided the site and data on experimental conditions for field trials.
文摘Amid accelerating global land degradation,establishing high-efficiency ecological restoration principles and frameworks is crucial.Here,we explore the application of threshold effects in the ecological restoration process based on field experiments and globally available experimental data from 173 sites.Combining data integration analysis and meta-analysis,we collectively verified the universality of threshold effects in grasslands.The global grasslands’average nitrogen application threshold is 3.78 g·m^(-2)·yr^(−1),while the threshold value of degraded grassland(3.65 g·m^(-2)·yr^(−1))is lower than that of nondegraded grassland(5.90 g·m^(-2)·yr^(−1)).The low nitrogen-driven thresholds are affected by degradation status,climate(precipitation and temperature),and other site conditions,but not fertilization forms.Independent experiments further demonstrated that an increase in soil moisture content can lead to the disappearance of nitrogen threshold effects,revealing that ecological threshold effects are influenced by ecosystem stress factors.Following the significant increase in plant biomass triggered by the nitrogen threshold,the ecosystem undergoes systemic improvement.Soil organic carbon,urease activity,soil microbial diversity,and other soil properties are significantly enhanced.Soil nitrogen cycle-related microbial communities and soil physicochemical attributes are significantly activated.The results indicate that a threshold response pattern may develop before nitrogen saturation is reached,and low nitrogen input can boost productivity and improve the plant-soil-microbe system.Our findings reveal a nonprogressive path of restoration in degraded ecosystems,and thus,restoration based on threshold effects can offer an efficient and safe solution to combat ecological degradation.
基金supported by the Anhui Provincial Natural Science Foundation (Grant No.2508085J006)CASHIPS Director's Fund (Grant No.YZJJ202207-CX)。
文摘The zigzag nitrogen chain,similar to the Ch-N structure,has long been considered as a potential high-energy-density structure.However,all the previously predicted zigzag N-chain structures,similar to Ch-N,exhibited imaginary frequencies in their phonon spectra at 0 GPa.Here,we conducted a systematic investigation of P-N compounds using first-principles calculations,uncovering a series of structurally similar stable phases,C2/m-PN_(x)(x=6,8,10,12,and 14),in which N forms zigzag N chains similar to those in Ch-N.In P-N compounds,the longest zigzag N-chain,which can theoretically remain stable under ambient pressure,is the N-chain composed of 14 N atoms in C2/m-PN14.If the N-chain continues to grow,imaginary interchain vibrational frequencies arise in the system.Notably,N chains with an even number of atoms were more likely to be energetically favorable.The five C2/m-PN_(x) phases and one metastable phase(R-PN_(6))exhibited remarkable stability and excellent detonability at ambient pressure,indicating that they are promising candidates for high-energy-density materials.In addition,R-PN_(6) was the first structure to stabilize the N_(6) ring through covalent bonding,with the covalent network contributing to its high hardness(47.59 GPa).
基金support for carrying out this work was provided by the Doctoral Research Foundation of Weifang University(2024BS20)Science and Technology Development Plan Foundation of Weifang(2024GX017).
文摘Photocatalytic nitrogen fixation (PNF) is a promising alternative to the Haber-Bosch process.It achieves green ammonia production by utilizing solar energy for nitrogen fixation under mild conditions.While nanoscale photocatalysts offer enhanced performance due to their high surface area and abundant active sites,their small size makes them difficult to recover and prone to agglomeration.These bottlenecks severely limit industrial application.A promising solution is to immobilize the catalysts onto support surfaces.This paper provides a systematic review of recent advances in the design of immobilized photocatalysts for ammonia synthesis.It begins by outlining the key benefits of immobilization strategies,particularly in improving catalyst stability,recyclability,and overall photocatalytic performance.The working mechanisms and features of various immobilization techniques are then categorized and explained,covering physical adsorption/deposition,chemical bonding,in situ growth,and hybrid physico-chemical methods.Supported materials and common substrate types are also summarized.Furthermore,the widely used configurations of photoreactors suitable for immobilized systems are introduced.Finally,the review identifies current research limitations and challenges,and offers perspectives on future developments in the field of immobilized photocatalysis.
基金supported by the National Natural Science Foundation of China(Nos.42472316,42072286 and 41761144059)the National Key Research and Development Program of China(No.2023YFC3706901)Qinchuangyuan"Scientist+Engineer"Team Development Program of the Shaanxi Provincial Department of Science and Technology(No.2022KXJ-005).
文摘Using unscientific agricultural methods can harm human health by increasing harmful nitrate(NO_(3)−)levels in groundwater,as observed in the Yinchuan Plain.This research utilized hydrochemical data,dual isotopic data,the MixSIAR model,and the uncertainty index(UI90)to detect the potential sources of groundwater NO_(3)−,track NO_(3)−conversion processes,and calculate the apportionment of each groundwater NO_(3)−source in the agricultural lands of the Yinchuan Plain.The results show that soil organic nitrogen accounted for 49.4%,and N-fertilizers contributed 30.4%,making them the two main contributors to NO_(3)-contamination in groundwater.Long-term N-fertilization enhances soil organic nitrogen accumulation,resulting in NO_(3)−leaching into groundwater during irrigation.The highest uncertainty regarding soil organic nitrogen and N-fertilizers may stem from changes in groundwater flow patterns,unbalanced N-fertilization,irrigation,and precipitation.Denitrification is the dominant process,resulting in lower NO_(3)−concentrations in groundwater in most areas.As a result,most groundwater in the Yinchuan Plain is generally safe for human consumption,except the specific areas in Qingtongxia City and Wuzhong City.Flood irrigation can increase the leaching of NO_(3)−into groundwater,and the repeated recharge of groundwater contaminated with high NO_(3)−levels could also be a potential source of NO_(3)−contamination in agricultural areas.This research provides scientific guidance for sustainable groundwater management in the Yinchuan Plain,mitigating the risk of groundwater NO_(3)−pollution.
基金Supported by the National Natural Science Foundation of China(Nos.42141003,42176147)the National Key Research and Development Program of China(No.2022YFF0802204)the Xiamen Key Laboratory of Urban Sea Ecological Conservation and Restoration(USER)(Nos.USER2021-1,USER2021-5)。
文摘Ecological floating bed is an important biological remediation method for water pollution control.During the removal of excess nutrients and pollutants,changes in environmental factors affect the characteristics of microorganisms in aquatic ecosystems.To understand the influences of ecological floating beds on size-fractionated microorganisms,we investigated the community assembly and nitrogen metabolic characteristics of three size-fractionated microorganism groups in the ecological floating bed area,using 18S rDNA,16S rDNA metabarcoding,and metagenomic sequencing techniques.Firstly,we discovered substantial differences between size-fractionated groups in the diversity and compositions of both microeukaryotic and bacterial communities,as well as the influences of floating beds on specific groups.The floating beds appeared to provide more habitats for heterotrophs and symbiotes while potentially inhibiting the growth of certain phytoplankton(cyanobacteria).Secondly,we observed that microeukaryotic and bacterial communities were predominantly influenced by stochastic and deterministic processes,respectively,and they both exhibited distinct patterns across different size-fractionated groups.Notably,microeukaryotic community assembly demonstrated a greater sensitivity to ecological floating beds,as indicated by an increase in dispersal limitation processes.Finally,the nitrogen metabolism functional genes revealed that microbes associated with large-sized particles played a crucial role in dissimilatory nitrate reduction to ammonium(DNRA)and denitrification processes within the floating bed area,thereby facilitating the removal of excess nitrogen nutrients from the water.In contrast,freeliving microorganisms from small-sized groups were linked mainly to the genes involved in nitrogen assimilation and assimilatory nitrate reduction to ammonium(ANRA)processes.These findings help understand the impact of ecological floating beds on the diversity and functional characteristics of microorganism communities in different size-fractionated groups.
基金supported by China Hunan Provincial Science&Technology Department(No.2023NK2031)the Natural Science Foundation of Hunan Province(No.2023JJ40031)the Ministry of Human Resources and Social Security(No.H20240365).
文摘To explore the adaptive mechanisms of the partial nitritation-anammox(PNA)process under high salinity stress during kitchen wastewater treatment,focusing on their physiological and molecular responses through metagenomic analysis.An airlift inner-circulation partition bioreactor(AIPBR)was developed,featuring an inner cylinder and a flow guide tube to create distinct oxygen gradients,facilitating the study of microbial adaptation under varying salt conditions.The AIPBR was operated with synthetic wastewater containing ammonium concentrations of 1800±100 mg/L and salinity gradients ranging from 1 to 10 g/L,followed by a fixed salinity period at 6 g/L,with ammonium concentrations approximately 850 mg/L.High-throughput metagenomic analysis revealed shifts in functional genes and metabolic pathways in response to salinity stress.Anammox bacteria adapted by enriching genes involved in the synthesis of osmoprotective compounds and activating energy-producing pathways like the tricarboxylic acid cycle(TCA).These adaptations,along with modifications in membrane composition,were essential for sustaining system stability under elevated salinity.Under prolonged high salinity stress,anaerobic ammonium oxidizing(AnAOB)exhibited improved salt tolerance,maintaining a total nitrogen removal efficiency above 85%and stabilizing after an adaptation phase.The metagenomic data revealed a marked enrichment of genes associated with ion transport,stress response mechanisms,and DNA repair pathways.Changes in microbial community composition favored salt-tolerant species,supporting system stability.These findings highlight the applicability of the developed bioreactor for scaling up the PNA process to handle high-salinity wastewater,providing a promising avenue for sustainable nitrogen removal in challenging environments.
基金supported by the National Natural Science Foundation of China(No.52370112).
文摘In order to address the evolving emission characteristics of oxygenated volatile organic compounds(OVOCs),it is essential to develop adsorbent materials specifically designed for the efficient adsorption of OVOCs with large kinetic diameters.In this study,we used co-pyrolysis to prepare a series of graded porous carbon materials with well-developed micropores by adjusting the doping ratios of root nodules and pretreated cellulose.The material with root nodule to cellulose mass ratio of 1:1(TCC-RN-1)exhibited the highest saturated adsorption capacity for butyl acetate(834 mg/g).This can be attributed to enhanced pore size distribution from nodule doping,which facilitates the development of a micropore-graded structure.Additionally,the nodules acted as auxiliary activating agents that enhanced the KOH micropore regulation effect during the activation stage,resulting in the highest micropore volume(0.863 cm^(3)/g).The doping of root nodules facilitated the formation of additional defects on the surface of the porous carbon material,leading to a more disordered arrangement that improved pollutant adsorption.Furthermore,TCC-RN-1 demonstrated good thermal stability in an air atmosphere,main-taining a butyl acetate adsorption capacity exceeding 95%after five adsorption-desorption cycles.This indicates its favorable potential for industrial applications.
基金Supported by Science and Technology Project of China Tobacco Zhejiang Industrial Co.,Ltd.(2023330000340093).
文摘[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Province,evaluating various combinations of planting density and nitrogen rate for Chuxue 80.[Results]At the maturity stage,the TN1 treatment(5 kg N per 667 m^(2) with a density of 1900 plants per 667 m^(2))demonstrated the most favorable agronomic performance.The TN9 treatment(11 kg N per 667 m^(2) with a density of 1110 plants per 667 m^(2))achieved the highest wrapper tobacco yield and output value.Meanwhile,the TN5 treatment(8 kg N per 667 m^(2) with a density of 1515 plants per 667 m^(2))resulted in the best smoking quality.[Conclusions]The TN9 treatment,with a planting density of 1110 plants per 667 m^(2) and a nitrogen application rate of 11 kg per 667 m^(2),is recommended as the optimal cultivation practice for Chuxue 80 in Hubei Province.
基金supported by the National Natural Science Foundation of China(Nos.22361162668 and 42021004)the National Key Research and Development Program of China(No.2023YFC3706203).
文摘Along with decrease of fine particulate matter(PM_(2.5))concentration in recent years in China,secondary species become increasingly important.This work focuses on characterizing secondary components,and a few important groups of organics including organic nitrogen(ON),organonitrates(OrgN),organosulfates(OS)and polycyclic aromatic hydrocarbons(PAHs),via online measurement of submicron aerosols(PM_(1))in Nanjing,China,during 2022 summer.The average PM_(1) concentration was 15.39μg/m^(3),dominated by secondary components(69.1%),which were even more important at higher PM_(1) levels.The primary organic aerosols(POA)were from traffic,industry and cooking;the two secondary OA factors were both closely linked with photochemistry,with one(OOA1)being relatively fresh and important in early afternoon and another(OOA2)being aged and important in late afternoon.Sulfate formation was also governed by photochemistry but resembled that of OOA2 not OOA1;nitrate formation was associated strongly with heterogeneous hydrolysis and thermodynamic equilibrium.Results also reveal a possible photochemical reaction channel from POA to OOA1,then to OOA2.Case studies show that formations of secondary components responded differently to different weather conditions and governed summer PM_(1) pollution.The average ON,OrgN,OS and PAHs concentrations were determined to be 122.8,84.4,45.6 and 3.3 ng/m^(3),respectively.ON was dominated by primary sources(53.8%).OrgN varied similarly to nitrate.OS formation was linked with aqueous-phase reactions,which were insignificant therefore its level was low.PAHs was mainly from traffic,and photochemical oxidation might be its important sink during afternoon.
基金funded by the National Natural Science Foundation of China (31760363)the Earmarked Fund for CARS (CARS-14-1-16)+1 种基金the Gansu Education Science and Technology Innovation Industry Support Program,China (2021CYZC-38)the Gansu Provincial Key Laboratory of Arid Land Crop Science,Gansu Agricultural University,China (GSCS-2020-Z6)。
文摘Lodging is a major constraint limiting oil flax production efficiency in northern China.Crop lodging susceptibility is closely related to stem lignin content,and the regulatory mechanisms by which nitrogen and potassium fertilization interactively influence lignin biosynthesis in oil flax stems require further investigation.Therefore,this study aimed to enhance lodging resistance and increase grain yield in oil flax.We examined the interactive effects of different nitrogen (75,150,and 225 kg N ha^(–1)) and potassium (60 and 90 kg K_(2)O ha^(–1)) fertilizer rates on lignin metabolism,lodging resistance,and grain yield during the 2022 and 2023 growing seasons.Results indicated that nitrogen and potassium fertilizer levels and their interactions promoted lignin accumulation,improved lodging resistance,and increased grain yield.Compared to the control (CK),the75–150 kg N ha^(–1) combined with 60 kg K_(2)O ha^(–1) treatments significantly enhanced the activities of key lignin-synthesizing enzymes (tyrosine ammonia-lyase (TAL),phenylalanine ammonia-lyase (PAL),cinnamyl alcohol dehydrogenase (CAD),and peroxidase (POD)) and upregulated the expression of 4CL1 and F5H3 genes,leading to a 29.63–43.30%increase in lignin content,improved stem bending strength and lodging resistance index,and a 23.27–32.34%increase in grain yield.Correlation analysis revealed that nitrogen and potassium fertilizers positively regulated enzyme activities and gene expression related to lignin biosynthesis,thereby facilitating lignin accumulation and enhancing stem mechanical strength and lodging resistance.Positive correlations were observed among lignin-related enzyme activities,gene expression,lodging resistance traits,and grain yield.In summary,the application of 75–150 kg N ha^(–1) in conjunction with 60 kg K_(2)O ha^(–1)promoted lignin biosynthesis and accumulation,enhanced lodging resistance,and increased grain yield in oil flax grown in the dryland farming region of central Gansu,China.Furthermore,this treatment provides a technical basis for cultivating stress-tolerant and high-yield oil flax in arid regions.
基金Supported by the Laoshan Laboratory(No.LSKJ202204005)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23050502)+2 种基金the State Key Program of National Natural Science Foundation of China(No.42130411)the International Science Partnership Program of the Chinese Academy of Sciences(Nos.121311KYSB20190029,133137KYSB20200002)the Key Deployment Project of Centre for Ocean Mega-Research of Science,Chinese Academy of Sciences(CAS)(No.COMS2019J03)。
文摘Nutrients play a crucial role in sustaining marine ecosystems and supporting mariculture,especially in seaweed aquaculture.Currently,seaweed farming,such as kelp cultivation,is entirely dependent on the natural supply of nutrients.Sanggou Bay in Shandong Peninsula,Yellow Sea,is renowned for its 60-year history of kelp cultivation;however,it is recently facing an increasing demand for nitrogen and phosphorus due to the expansion in aquaculture scale and production.There is no doubt that nutrient addition can enhance and sustain the production,but it is crucial to understand its effect on kelp growth under current nutrients condition and the potential ecological risks.Our in-field nutrient enrichment experiments show that nitrogen and phosphorus additions promoted the kelp biomass during the early growth stages,and have no adverse effects on phytoplankton or seawater nutrient levels throughout the experiment.From a long-term perspective,increasing nutrient supply appears to be an essential strategy for sustaining the aquaculture of kelp.
基金supported by the Science and Technology Project of Hebei Education Department(No.QN2023028)the Natural Science Foundation of Hebei Province(No.C2022201042)+1 种基金the High-level Talent Research Funding Project of Hebei University(Nos.521000981405 and 521000981186)the Collaborative Innovation Center for Baiyangdian Basin Ecological Protection and Beijing-Tianjin-Hebei Sustainable Development.
文摘Climate warming and atmospheric nitrogen(N)deposition have profound influences on the terrestrial biosphere.However,how these two global change drivers affect phytoplankton which are important primary producers in wetlands with large carbon stocks and complex hydrological fluctuations remain largely unclear.As part of a two-year field experiment in a freshwater wetland,this study was conducted to investigate the effects of nighttime warming and N addition on phytoplankton biomass in the North China Plain.The results showed that neither nighttime warming nor N addition influenced the Shannon-Wiener index of phytoplankton community.Nighttime warming did not change phytoplankton biomass,likely due to the different warming impacts on dominant phyla and in different seasons.Decreased phytoplankton biomass in spring because of the increased water pH and submerged plant coverage was compensated by the enhanced biomass in autumn due to the reduced dissolved oxygen and submerged plant coverage,leading to the neutral change of phytoplankton biomass under warming.Nitrogen addition elevated phytoplankton biomass by 11.6%,which could be attributed to the enhanced nutrient availability and reduced submerged plant coverage.Positive relationships of methane(CH4)emission rates at the water-air interface with phytoplankton biomass indicated the potentially crucial role of phytoplankton in mediating wetland CH4 cycling through photosynthesis-driven metabolisms.The findings suggested the seasonal variation of phytoplankton and their potential responses to nighttime warming and N deposition,which may provide a more accurate basis for assessing the global change-carbon feedback in wetland ecosystems.
基金funded by the National Natural Science Foundation of China(Nos.82103686 and 22101267)the China Postdoctoral Science Foundation(No.2021M692905 and 2024T170832)Natural Science Foundation of Henan Province(242300421123).
文摘Nitrogen-containing structures represent a significant branch exhibiting remarkable biological activity,surpassing non-nitrogen architectures.Given the vast array of nitrogen-containing compounds and their crucial role in the pharmaceutical industry,chemists have been motivated to devise efficient,cost-effective,and practical methods for C-N bond formation.Significant advancements have been achieved in this cutting-edge field over the past few decades.This review aims to encapsulate the latest progress in C-N bond formation via the photocatalytic C-H amination process.Initially,we provide a comprehensive introduction to C-H amination transformations.Subsequently,we categorize these photochemical conversions into two parts:intramolecular and intermolecular C-H amination.To elucidate the underlying principles of specific illustrative examples,we have carefully chosen and elaborated on the reaction mechanisms,representative experimental outcomes,and applications.
基金supported by the National Natural Science Foundation of China(Grant No.22479046,22461142135)。
文摘Cellulose,the most abundant and renewable biopolymer,offers a sustainable and cost-effective solution for regulating lithium electrodeposition toward safer lithium metal batteries,thanks to its high nanofibrous structure and intrinsic lithiophilic property.In this work,we introduce interface-engineered cellulose-based separators by converting intrinsic hydroxyl groups on cellulose nanofibers(CNFs)to nitrogen functionalities through a trace conducting polymer coating.Both experimental and theoretical results reveal that the nitrogen moieties disrupt the compact hydrogen bond network within hydroxyl cellulose,enabling multiple nitrogen-lithium interactions that enhance lithium ion transport.In addition to an extraordinary Li^(+)transference number of 0.86 and a high ionic conductivity of 1.1 mS cm^(-1),the nitrogen-functionalized CNF contributes to a uniform electric field and Li^(+)concentration distribution across the lithium metal surface.This facilitates the formation of a LiF-rich solid electrolyte interface and suppresses Li dendrite growth.Consequently,Li‖Li cells demonstrate stable plating/stripping cycles for approximately 3000 h at a current density of 1 mA cm^(-2) with a fixed capacity of 1 mAh cm^(-2),while maintaining a low overpotential of 15 mV.Our work provides valuable insights into the surface functionalization of natural biomass for advancing sustainable energy storage technologies.
