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Nonsense-mediated decay (NMD) and autophagy play pivotal roles in restricting virus infection in plants. However, the interconnection between these two pathways in viral infections has not been explored. Here, it is shown that overexpression of NbSMG7 and NbUPF3 attenuates cucumber green mottle mosaic virus (CGMMV) infection by recognizing the viral internal termination codon and vice versa. NbSMG7 is subjected to autophagic degradation, which is executed by its interaction with one of the autophagy-related proteins, NbATG8i. Mutation of the ATG8 interacting motif (AIM) in NbSMG7 (SMG7mAIM1) abolishes the interaction and comprises its autophagic degradation. Silencing of NbSMG7 and NbATG8i, or NbUPF3 and NbATG8i, compared to silencing each gene individually, leads to more virus accumulations, but overexpression of NbSMG7 and NbATG8i fails to achieve more potent virus inhibition. When CGMMV is co-inoculated with NbSMG7mAIM1 or with NbUPF3, compared to co-inoculating with NbSMG7 in NbATG8i transgene plants, the inoculated plants exhibit milder viral phenotypes. These findings reveal that NMD-mediated virus inhibition is impaired by the autophagic degradation of SMG7 in a negative feedback loop, and a novel regulatory interplay between NMD and autophagy is uncovered, providing insights that are valuable in optimizing strategies to harness NMD and autophagy for combating viral infections.
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Autofagia , Enfermedades de las Plantas , Autofagia/genética , Enfermedades de las Plantas/virología , Enfermedades de las Plantas/genética , Degradación de ARNm Mediada por Codón sin Sentido/genética , Retroalimentación Fisiológica , Tobamovirus/genética , Tobamovirus/metabolismo , Nicotiana/virología , Nicotiana/genética , Nicotiana/metabolismoRESUMEN
The estuarine plastisphere, a novel ecological habitat in the Anthropocene, has garnered global concerns. Recent geochemical evidence has pointed out its potential role in influencing nitrogen biogeochemistry. However, the biogeochemical significance of the plastisphere and its mechanisms regulating nitrogen cycling remain elusive. Using 15N- and 13C-labelling coupled with metagenomics and metatranscriptomics, here we unveil that the plastisphere likely acts as an underappreciated nitrifying niche in estuarine ecosystems, exhibiting a 0.9 ~ 12-fold higher activity of bacteria-mediated nitrification compared to surrounding seawater and other biofilms (stone, wood and glass biofilms). The shift of active nitrifiers from O2-sensitive nitrifiers in the seawater to nitrifiers with versatile metabolisms in the plastisphere, combined with the potential interspecific cooperation of nitrifying substrate exchange observed among the plastisphere nitrifiers, collectively results in the unique nitrifying niche. Our findings highlight the plastisphere as an emerging nitrifying niche in estuarine environment, and deepen the mechanistic understanding of its contribution to marine biogeochemistry.
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Bacterias , Biopelículas , Estuarios , Nitrificación , Agua de Mar , Agua de Mar/microbiología , Bacterias/metabolismo , Bacterias/genética , Biopelículas/crecimiento & desarrollo , Ecosistema , Microbiota/fisiología , Metagenómica , Filogenia , Ciclo del Nitrógeno , Nitrógeno/metabolismo , Isótopos de Nitrógeno/metabolismoRESUMEN
Growing evidence indicates that plant community structure and traits have changed under climate warming, especially in cold or high-elevation regions. However, the impact of these warming-induced changes on ecosystem carbon sequestration remains unclear. Using a warming experiment on the high-elevation Qinghai-Tibetan Plateau, we found that warming not only increased plant species height but also altered species composition, collectively resulting in a taller plant community associated with increased net ecosystem productivity (NEP). Along a 1,500 km transect on the Plateau, taller plant community promoted NEP and soil carbon through associated chlorophyll content and other photosynthetic traits at the community level. Overall, plant community height as a dominant trait is associated with species composition and regulates ecosystem C sequestration in the high-elevation biome. This trait-based association provides new insights into predicting the direction, magnitude and sensitivity of ecosystem C fluxes in response to climate warming.
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Secuestro de Carbono , Ecosistema , Calentamiento Global , Plantas/metabolismo , Fotosíntesis , Cambio Climático , Altitud , Tibet , Carbono/metabolismo , Suelo/químicaRESUMEN
Symbiotic nitrogen (N) fixation (SNF), replenishing bioavailable N for terrestrial ecosystems, exerts decisive roles in N cycling and gross primary production. Nevertheless, it remains unclear what determines the variability of SNF rate, which retards the accurate prediction for global N fixation in earth system models. This study synthesized 1230 isotopic observations to elucidate the governing factors underlying the variability of SNF rate. The SNF rates varied significantly from 3.69 to 12.54 g N m-2 year-1 across host plant taxa. The traits of host plant (e.g. biomass characteristics and taxa) far outweighed soil properties and climatic factors in explaining the variations of SNF rate, accounting for 79.0% of total relative importance. Furthermore, annual SNF yield contributed to more than half of N uptake for host plants, which was consistent across different ecosystem types. This study highlights that the biotic factors, especially host plant traits (e.g. biomass characteristics and taxa), play overriding roles in determining SNF rate compared with soil properties. The suite of parameters for SNF lends support to improve N fixation module in earth system models that can provide more confidence in predicting bioavailable N changes in terrestrial ecosystems.
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Ecosistema , Fijación del Nitrógeno , Biomasa , Planeta Tierra , SueloRESUMEN
Returning organic nutrient sources (for example, straw and manure) to rice fields is inevitable for coupling crop-livestock production. However, an accurate estimate of net carbon (C) emissions and strategies to mitigate the abundant methane (CH4) emission from rice fields supplied with organic sources remain unclear. Here, using machine learning and a global dataset, we scaled the field findings up to worldwide rice fields to reconcile rice yields and net C emissions. An optimal organic nitrogen (N) management was developed considering total N input, type of organic N source and organic N proportion. A combination of optimal organic N management with intermittent flooding achieved a 21% reduction in net global warming potential and a 9% rise in global rice production compared with the business-as-usual scenario. Our study provides a solution for recycling organic N sources towards a more productive, carbon-neutral and sustainable rice-livestock production system on a global scale.
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Nitrógeno , Oryza , Animales , Nitrógeno/análisis , Agricultura , Suelo , Carbono , Agua , Óxido Nitroso/análisis , Fertilizantes/análisis , GanadoRESUMEN
Nitrous oxide (N2 O) is a potent greenhouse gas, and its mitigation is a pressing task in the coming decade. However, it remains unclear which specific process between concurrent nitrification and denitrification dominates worldwide N2 O emission. We snagged an opportunity to ascertain whence the N2 O came and which were the controlling factors on the basis of 1315 soil N2 O observations from 74 peer-reviewed articles. The average N2 O emission derived from nitrification (N2 On ) was higher than that from denitrification (N2 Od ) worldwide. The ratios of nitrification-derived N2 O to denitrification-derived N2 O, hereof N2 On :N2 Od , exhibited large variations across terrestrial ecosystems. Although soil carbon and nitrogen content, pH, moisture, and clay content accounted for a part of the geographical variations in the N2 On :N2 Od ratio, ammonia-oxidizing microorganisms (AOM):denitrifier ratio was the pivotal driver for the N2 On :N2 Od ratios, since the AOM:denitrfier ratio accounted for 53.7% of geographical variations in N2 On :N2 Od ratios. Compared with natural ecosystems, soil pH exerted a more remarkable role to dictate the N2 On :N2 Od ratio in croplands. This study emphasizes the vital role of functional soil microorganisms in geographical variations of N2 On :N2 Od ratio and lays the foundation for the incorporation of soil AOM:denitrfier ratio into models to better predict N2 On :N2 Od ratio. Identifying soil N2 O derivation will provide a global potential benchmark for N2 O mitigation by manipulating the nitrification or denitrification.
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Desnitrificación , Nitrificación , Ecosistema , Ciclo del Nitrógeno , Suelo/química , Nitrógeno/análisis , Óxido Nitroso/análisis , AmoníacoRESUMEN
N6-methyladenosine (m6A) is the most abundant eukaryotic mRNA modification and is involved in various biological processes. Increasing evidence has implicated that m6A modification is an important anti-viral defense mechanism in mammals and plants, but it is largely unknown how m6A regulates viral infection in plants. Here we report the dynamic changes and functional anatomy of m6A in Nicotiana benthamiana and Solanum lycopersicum during Pepino mosaic virus (PepMV) infection. m6A modification in the PepMV RNA genome is conserved in these two species. Overexpression of the m6A writers, mRNA adenosine methylase A (MTA), and HAKAI inhibit the PepMV RNA accumulation accompanied by increased viral m6A modifications, whereas deficiency of these writers decreases the viral RNA m6A levels but enhances virus infection. Further study reveals that the cytoplasmic YTH-domain family protein NbECT2A/2B/2C as m6A readers are involved in anti-viral immunity. Protein-protein interactions indicate that NbECT2A/2B/2C interact with nonsense-mediated mRNA decay (NMD)-related proteins, including NbUPF3 and NbSMG7, but not with NbUPF1. m6A modification-mediated restriction to PepMV infection is dependent on NMD-related factors. These findings provide new insights into the functionality of m6A anti-viral activity and reveal a distinct immune response that NMD factors recognize the m6A readers-viral m6A RNA complex for viral RNA degradation to limit virus infection in plants.
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Virus de Plantas , Virosis , Humanos , Degradación de ARNm Mediada por Codón sin Sentido , Virus de Plantas/genética , ARN , ARN Mensajero/genéticaRESUMEN
The current Special Issue, entitled "Friction, Corrosion and Protection of Material Surfaces", aims to discuss the state-of-the-art research progress regarding the friction and corrosion behaviors of new materials and advanced protective materials or technologies, with a special focus on the understanding of underlying friction and corrosion mechanisms and modification approaches of material surfaces against friction and corrosion in order to guide the design and preparation of materials with high performance for practical applications [...].
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Previous assessments generated divergent estimates of global terrestrial soil nitrous oxide (N2O) emission and its spatial distributions, which did not match the observed data well. The objectives of this study were to generate a global map of terrestrial soil N2O emissions based on field observations (n = 5549) and quantify the contribution of different variables for predicting the global variation of N2O emissions. We provided spatially explicit maps of annual soil N2O emission rates across forest, grassland and cropland using the random forest approach. The global mean soil N2O emission rate in our data-driven model was 0.059 ± 0.006 g N m-2 year-1, which was lower than the estimates from previous model ensembles. Soil N2O emissions were higher in the northern than southern hemisphere. The average annual soil N2O emission rate of cropland (0.094 ± 0.009 g N m-2 year-1) was higher than that of forest (0.039 ± 0.004 g N m-2 year-1) and grassland (0.045 ± 0.007 g N m-2 year-1). In addition, we found that soil nitrogen substrates dominated the changes in soil N2O emissions and the relative importance of nitrate, ammonium, and fertilizer in predicting soil N2O emissions was greater than that of mean annual temperature and precipitation. Our data-driven model results implied that previous process-based model may overestimate the global soil N2O emission rates due to limited validation data and incomplete assumptions on related-mechanisms. This study highlights the importance of global field observations in N2O emission estimation, which can provide an independent dataset to constrain previous process-based models for better prediction.
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Autophagy plays an active anti-viral role in plants. Increasing evidence suggests that viruses can inhibit or manipulate autophagy, thereby winning the arms race between plants and viruses. Here, we demonstrate that overexpression of an m6A writer from Solanum lycopersicum, SlHAKAI, could negatively regulate pepino mosaic virus (PepMV) infection, inhibit viral RNA and protein accumulations by affecting viral m6A levels in tomato plants and vice versa. The PepMV-encoded RNA-dependent RNA polymerase (RdRP) directly interacts with SlHAKAI and reduces its protein accumulation. The RdRP-mediated decreased protein accumulation of SlHAKAI is sensitive to the autophagy inhibitor 3-methyladenine and is compromised by knocking down a core autophagy gene. Furthermore, PepMV RdRP could interact with an essential autophagy-related protein, SlBeclin1. RdRP, SlHAKAI, and SlBeclin1 interaction complexes form bright granules in the cytoplasm. Silencing of Beclin1 in Nicotiana benthamiana plants abolishes the RdRP-mediated degradation of SlHAKAI, indicating the requirement of Beclin1 in this process. This study uncovers that the PepMV RdRP exploits the autophagy pathway by interacting with SlBeclin1 to promote the autophagic degradation of the SlHAKAI protein, thereby inhibiting the m6A modification-mediated plant defense responses. Supplementary Information: The online version contains supplementary material available at 10.1007/s42994-023-00097-6.
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Climate change leads to increasing temperature and more extreme hot and drought events. Ecosystem capability to cope with climate warming depends on vegetation's adjusting pace with temperature change. How environmental stresses impair such a vegetation pace has not been carefully investigated. Here we show that dryness substantially dampens vegetation pace in warm regions to adjust the optimal temperature of gross primary production (GPP) ( T opt GPP ) in response to change in temperature over space and time. T opt GPP spatially converges to an increase of 1.01°C (95% CI: 0.97, 1.05) per 1°C increase in the yearly maximum temperature (Tmax ) across humid or cold sites worldwide (37o S-79o N) but only 0.59°C (95% CI: 0.46, 0.74) per 1°C increase in Tmax across dry and warm sites. T opt GPP temporally changes by 0.81°C (95% CI: 0.75, 0.87) per 1°C interannual variation in Tmax at humid or cold sites and 0.42°C (95% CI: 0.17, 0.66) at dry and warm sites. Regardless of the water limitation, the maximum GPP (GPPmax ) similarly increases by 0.23 g C m-2 day-1 per 1°C increase in T opt GPP in either humid or dry areas. Our results indicate that the future climate warming likely stimulates vegetation productivity more substantially in humid than water-limited regions.
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Cambio Climático , Plantas , Estrés Fisiológico , Temperatura , Sequías , EcosistemaRESUMEN
Soil anammox is an environmentally friendly way to eliminate reactive nitrogen (N) without generating nitrous oxide. Nevertheless, the current earth system models have not incorporated the anammox due to the lack of parameters in anammox rates on a global scale, limiting the accurate projection for N cycling. A global synthesis with 1212 observations from 89 peer-reviewed papers showed that the average anammox rate was 1.60 ± 0.17 nmol N g-1 h-1 in terrestrial ecosystems, with significant variations across different ecosystems. Wetlands exhibited the highest rate (2.17 ± 0.31 nmol N g-1 h-1 ), followed by croplands at 1.02 ± 0.09 nmol N g-1 h-1 . The lowest anammox rates were observed in forests and grasslands. The anammox rates were positively correlated with the mean annual temperature, mean annual precipitation, soil moisture, organic carbon (C), total N, as well as nitrite and ammonium concentrations, but negatively with the soil C:N ratio. Structural equation models revealed that the geographical variations in anammox rates were primarily influenced by the N contents (such as nitrite and ammonium) and abundance of anammox bacteria, which collectively accounted for 42% of the observed variance. Furthermore, the abundance of anammox bacteria was well simulated by the mean annual precipitation, soil moisture, and ammonium concentrations, and 51% variance of the anammox bacteria was accounted for. The key controlling factors for soil anammox rates differed from ecosystem type, for example, organic C, total N, and ammonium contents in croplands, versus soil C:N ratio and nitrite concentrations in wetlands. The controlling factors in soil anammox rate identified by this study are useful to construct an accurate anammox module for N cycling in earth system models.
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Compuestos de Amonio , Ecosistema , Oxidación Anaeróbica del Amoníaco , Nitritos , Anaerobiosis , Oxidación-Reducción , Microbiología del Suelo , Bacterias , Suelo/química , NitrógenoRESUMEN
Microbial community and interaction play crucial roles in ecological functions of soil including nutrient cycling carbon storage, and water maintenance etc. Numerous studies have shown that the application of fertilizers alters bacterial diversity; However, it remains unknown whether and how the continuous application of biogas slurry from anaerobic digestion affects the spatiotemporal heterogeneity of soil layers, complexity and stability of microbial networks, and functions related to C and N cycling. Here, we investigated the bacterial taxa of purple soils treated with swine biogas slurry for four different periods (0, 1, 3 and 8 years) and five different soil depths (20, 40, 60, 80 and 100 cm). The results showed that the application period of biogas slurry and soil depth were two powerful drivers of bacterial diversity and communities. Biogas slurry input resulted in marked changes in the bacterial diversity and composition at the soil depths of 0-60 cm. The relative abundances of Acidobacteriota, Myxococcot, and Nitrospirota decreased, while Actinobacteria, Chloroflexi, and Gemmatimonadota increased with repeated biogas slurry input. The decreasing complexity and stability of the bacterial network with decreasing nodes, links, robustness, and cohesions were found with increasing years of biogas slurry application, suggesting that the bacterial network of soils treated by the biogas slurry became more vulnerability compared with the control. Also, the linkages between the keystone taxa and soil properties were weakened after biogas slurry input, leading to the cooccurrence patterns being less affected by the keystones in the high level of nutrients. Metagenomic analysis confirmed that biogas slurry input increased the relative abundance of liable-C degradation and denitrification genes, which could highly impact the network properties. Overall, our study could give comprehensive understandings on the impacts of biogas slurry amendment on soils, which could be useful for maintaining sustainable agriculture and soil health with liquid fertilization.
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Biocombustibles , Suelo , Animales , Porcinos , Metagenómica , Bacterias/genética , Agricultura , Fertilizantes , Microbiología del SueloRESUMEN
The plastisphere is a new ecological niche. Compared to the surrounding water, microbial community composition associated with the plastisphere is known to differ with functional consequences. Here, this study characterized the bacterial and fungal communities associated with four types of plastisphere (polyethylene, polystyrene, polypropylene and polyvinyl chloride) in an estuarine habitat; assessed ecological functions including carbon, nitrogen, phosphorus and sulfur cycling, and determined the presence of antibiotic resistance genes (ARGs) and human pathogens. Stochastic processes dominated the community assembly of microorganisms on the plastisphere. Several functional genera related to nutrient cycling were enriched in the plastisphere. Compared to surrounding water and other plastisphere, the abundances of carbon, nitrogen and phosphorus cycling genes (cdaR, nosZ and chpy etc.) and ARGs (aadA2-1, cfa and catB8 etc.) were significantly increased in polyvinyl chloride plastisphere. In contrast, the polystyrene plastisphere was the preferred substrate for several pathogens being enriched with for example, Giardia lamblia 18S rRNA, Klebsiella pneumoniae phoE and Legionella spp. 23S rRNA. Overall, this study showed that different plastisphere had different effects on ecological functions and health risk in estuaries and emphasizes the importance of controlling plastic pollution in estuaries. Data from this study support global policy drivers that seek to reduce plastic pollution and offer insights into ecological functions in a new ecological niche of the Anthropocene.
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Microbiota , Poliestirenos , Humanos , Cloruro de Polivinilo , Plásticos , Agua , Farmacorresistencia Microbiana/genética , Antibacterianos , Nitrógeno , FósforoRESUMEN
Eutrophication generally promotes but destabilizes grassland productivity. Under eutrophication, plants tend to decrease biomass allocation to roots but increase aboveground allocation and light limitation, likely affecting community stability. However, it remains unclear to understand how shifting plant biomass allocation and light limitation regulate grassland stability in response to eutrophication. Here, using a 5-yr multiple nutrient addition experiment in an alpine meadow, we explored the role of changes in plant biomass allocation and light limitation on its community stability under eutrophication as well as traditionally established mechanisms (i.e., plant Shannon diversity, species asynchrony and grass subcommunity stability). Our results showed that nitrogen (N) addition, rather than phosphorus (P) or potassium (K) addition, significantly reduced the temporal stability of the alpine meadow. In accordance with previous studies, we found that N addition decreased plant Shannon diversity, species asynchrony and grass subcommunity stability, further destabilizing meadow community productivity. In addition, we also found the decrease in biomass allocation to belowground by N addition, further weakening its community stability. Moreover, this shifts in plant biomass allocation from below- to aboveground, intensifying plant light limitation. Further, the light limitation reduced plant species asynchrony, which finally weakened its community stability. Overall, in addition to traditionally established mechanisms, this study highlights the role of plant biomass allocation shifting from belowground to aboveground in determining grassland community stability. These "unseen" mechanisms might improve our understanding of grassland stability in the context of ongoing eutrophication.
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Pradera , Poaceae , Biomasa , Plantas , Eutrofización , Nitrógeno/análisis , Suelo , EcosistemaRESUMEN
Microplastics can profoundly alter nitrogen cycling. However, it remains poorly understood how microplastics impact soil nitrogen processes and generate N2O. A meta-analysis was conducted for this investigation based on 60 published studies to elucidate the effects of microplastics on soil nitrogen cycling, from genes to processes. Under microplastic exposure, the emissions of soil N2O was significantly increased (140.6%), while the nitrate reductase activities increased by 4.8%. The denitrification rate and number of denitrifier genes were increased by 17.8% and 10.6%, respectively. Meanwhile, the nitrification rate and nitrifier genes were not significantly altered, so did the nitrogen immobilization and mineralization rates. The additional emission of soil N2O might primarily from stimulated denitrification. Soil N2O emission and denitrification genes were always increased, regardless of the concentrations of microplastic or experiment duration. As a result, the nitrite was increased by 38.8% and nitrate was decreased by 22.4%, respectively. Interestingly, the N2O emission increments and copy number of denitrifiers genes diminished over time. This study revealed divergent changes in soil nitrogen processes and highlighted N2O emissions with a greater denitrification rate under microplastic exposure. The negative impacts of microplastics on soil health were revealed from the perspective of soil nitrogen availability and N2O emissions.
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Desnitrificación , Óxido Nitroso , Microplásticos , Plásticos , Nitrificación , Suelo , Nitrógeno/análisis , Microbiología del SueloRESUMEN
Agricultural soils are the hotspots of nitric oxide (NO) emissions, which are related to atmospheric pollution and greenhouse effect. Biochar application has been recommended as an important countermeasure, however, its mitigation efficiency is limited as biochar, under certain conditions, can stimulate soil nitrification. Therefore, biochar co-applied with nitrification inhibitor could optimize the mitigation potential of biochar. Herein, a laboratory-scale experiment was conducted to investigate the effects of co-application of biochar and nitrification inhibitor on NO emission, nitrogen cycling function and bacterial community in a tropical vegetable soil. Results showed that a single application of biochar or nitrification inhibitor significantly decreased NO emissions, and this mitigation effectiveness was amplified by their co-applications. Soil NO2--N intensity, along with abundances of AOB-amoA and nirK were significantly and positively correlated with cumulative NO emissions. The stimulated activity of ammonia monooxygenase and growths of AOB and total comammox Nitrospira by biochar were weakened by nitrification inhibitor, implying decreased nitrification-driven NO production. The nitric oxide reductase activity and related qnorB abundance in nitrification inhibitor-added soils were increased by biochar, indicating promoted NO consumption during denitrification. The nirK abundance and NO2--N intensity were decreased more by co-applications of biochar or nitrification inhibitor. Moreover, both biochar and nitrification inhibitor changed bacterial ß-diversity, and their co-application synergistically enriched Armatimonadetes and Verrucomicrobia abundances and decreased WPS-2 abundance. This study highlights that co-applications of biochar and nitrification inhibitor can make their respective advantages complementary to each other, thereby achieving a larger mitigation of NO emissions from agricultural soils in tropical regions.
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Nitrificación , Suelo , Bacterias , Carbón Orgánico , Óxido Nítrico , Dióxido de Nitrógeno , Óxido Nitroso , Microbiología del SueloRESUMEN
The alpine meadow is one of the most important ecosystems on the Qinghai-Tibet Plateau (QTP) due to its huge carbon storage and wide distribution. Evaluating the carbon fluxes in alpine meadow ecosystems is crucial to understand the dynamics of carbon storage in high-altitude areas. Here, we investigated the carbon fluxes at seasonal and inter-annual timescales based on 5 years of observations of eddy covariance fluxes in the Zoige alpine meadow on the eastern Tibetan Plateau. We found that the Zoige alpine meadow acted as a faint carbon source of 94.69 ± 86.44 g C m-2 y-1 during the observation periods with large seasonal and inter-annual variations (IAVs). At the seasonal scale, gross primary productivity (GPP) and ecosystem respiration (Re) were positively correlated with photosynthetic photon flux density (PPFD), average daily temperature (Ta), and vapor pressure (VPD) and had negative relationships with volumetric water content (VWC). Seasonal variations of net ecosystem carbon dioxide (CO2) exchange (NEE) were mostly explained by Ta, followed by PPFD, VPD, and VWC. The IAVs of GPP and Re were mainly attributable to the IAV of the maximum GPP rate (GPPmax) and maximum Re rate (Remax), respectively, both of which increased with the percentage of Cyperaceae and decreased with the percentage of Polygonaceae changes across years. The IAV of NEE was well explained by the anomalies of the maximum CO2 release rate (MCR). These results indicated that the annual net CO2 exchange in the alpine meadow ecosystem was controlled mainly by the maximum C release rates. Therefore, a better understanding of physiological response to various environmental factors at peak C uptake and release seasons will largely improve the predictions of GPP, Re, and NEE in the context of global change.
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In this work, we have successfully prepared core-shell nanoparticles (Fe3O4@PDA) wrapped with Ag using a simple and green synthesis method. Without an external reducing agent, silver nanoparticles (Ag NPs) with good dispersibility were directly reduced and deposited on a polydopamine (PDA) layer. Fe3O4@PDA@Ag showed excellent catalytic activity and recyclability for 4-nitrophenol, and also exhibited good catalytic selectivity for organic dyes (MO and MB). This simple and green synthesis method will provide a platform for other catalytic applications.
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Plant stoichiometry and nutrient allocation can reflect a plant's adaptation to environmental nutrient changes. However, the allocation strategies of carbon (C), nitrogen (N), and phosphorus (P) between leaf and fine root in response to wildfire have been poorly studied. Our primary objective was to elucidate the trade-off of elemental allocation between above- and belowground parts in response to the soil nutrient changes after a wildfire. We explored the allocation sloping exponents of C, N, and P between leaf and fine root at the species and community levels at four recovery periods (year 2, 10, 20, and 30) after moderately severe wildfire and one unburned treatment in boreal forests in Great Xing'an Mountains, northeast China. Compared with the unburned treatment, leaf C concentration decreased and fine root C increased at year 2 after recovery. The leaf N concentration at year 10 after recovery was higher than that of unburned treatment. Plant growth tended to be limited by P concentration at year 10 after recovery. Nutrient allocation between leaf and fine root differed between species and community levels, especially in the early recovery periods (i.e., 2 and 10 years). At the community level, the nutrient concentrations of the leaf changed more as compared to that of the fine root at year 2 after recovery when the fine root nutrients changed more than those of the leaf. The different C, N, and P allocation strategies advanced the understanding of plant adaptation to soil nutrient changes during the postfire ecosystem restoration.