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Fusarium solani exerts detrimental effects on plant growth, which is one of the reasons for the incidence of apple replant disease. Arbuscular mycorrhizal fungi (AMF) enhance plant resistance to Fusarium wilt; however, the mechanism remains poorly understood. Therefore, the present study investigated the symbiosis between apple and AMF and explored the physiology, especially nitrate metabolism, antioxidant defense, and photosynthetic performance, when infected by F. solani. The experiment was carried out with four treatments, namely -AMF - F. solani, -AMF + F. solani, -AMF + F. solani, and + AMF + F. solani. In this study, the -AMF + F. solani treatment increased the activity of enzymes associated with nitrogen metabolism, such as the nitrate and nitrite reductases, in the apple root system. The +AMF + F. solani treatment showed higher antioxidant enzyme activities than the -AMF + F. solani by F. solani infection. The apple seedlings of the +AMF + F. solani treatment decreased reactive oxygen accumulation and reduced the oxidative damages triggered by F. solani infection. The improvement in antioxidant capacity due to the +AMF + F. solani treatment was closely associated with the upregulation of genes related to the antioxidant system. The F. solani infection greatly damaged the photosynthetic process, while the +AMF + F. solani treatment significantly improved it compared to the -AMF + F. solani treatment. In conclusion, the study demonstrated that the apple-AMF symbiosis plays an active role in regulating the resistance against F. solani infection by enhancing defense response and nitrogen metabolism.
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Fusarium , Malus , Micorrizas , Nitrógeno , Enfermedades de las Plantas , Simbiosis , Fusarium/fisiología , Fusarium/patogenicidad , Micorrizas/fisiología , Nitrógeno/metabolismo , Malus/microbiología , Malus/genética , Malus/metabolismo , Malus/fisiología , Malus/inmunología , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/inmunología , Resistencia a la Enfermedad/genética , Antioxidantes/metabolismo , Raíces de Plantas/microbiología , Raíces de Plantas/genética , Raíces de Plantas/fisiología , Raíces de Plantas/metabolismo , Fotosíntesis , Plantones/microbiología , Plantones/fisiología , Plantones/genéticaRESUMEN
Carbon catabolite repression (CCR) is a very important mechanism for efficient use of carbon sources in the environment and is necessary for the regulation of fungal growth, development, and pathogenesis. Although there have been extensive studies conducted regarding this mechanism in fungi, little is yet known about the effects of CreA genes on Valsa mali. However, based on the results obtained in this study for the identification of the VmCreA gene in V. mali, it was determined that the gene was expressed at all stages of fungal growth, with self-repression observed at the transcriptional level. Furthermore, the functional analysis results of the gene deletion mutants (ΔVmCreA) and complements (CTΔVmCreA) showed that the VmCreA gene played an important role in the growth, development, pathogenicity, and carbon source utilization of V. mali.
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Ascomicetos , Proteínas Fúngicas , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Carbono/metabolismo , Virulencia/genéticaRESUMEN
Phytoremediation technology based on living green plants would clean up water pollution. Through hydroponic experiment, the effects of different concentration of 2, 4-dinitrophenol (2, 4-DNP) on the photosynthetic and chlorophyll fluorescence parameters of Salix babylonica, and the absorption and purification effect of S. babylonica on 2, 4-DNP were measured to explore the tolerance of S. babylonica to 2, 4-DNP and the feasibility to purify dinitrophenol waste water by it. The biomass, actual photochemical efficiency (PSII), net photosynthetic rate (Pn), photochemical quenching coefficient (qP), stomatal conductance (Gs), transpiration rate (Tr), maximum photochemical efficiency (Fv/Fm) and chlorophyll content of the S. babylonica showed downward trend with the increasing exposure concentrations of 2,4-DNP, but the intercellular CO2 concentration (Ci) appeared upward trend. Non-photochemical quenching coefficient (NPQ) increased at 5 mg L-1, then declined with the increase concentrations of 2, 4-DNP. In addition, the percent removal of 2, 4-DNP in 20 mg L-1 waste water was 91.4%. In conclusion, 2, 4-DNP significantly inhibits Pn of S. babylonica and the reduction of Pn was caused by decreasing Gs, carboxylation efficiency and chlorophyll content. When the concentration of 2, 4-DNP is not more than 20 mg L-1, S. babylonica can remove 2, 4-DNP efficiently.
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Salix , Aguas Residuales , Biodegradación Ambiental , Clorofila/análisis , Clorofila/farmacología , Dinitrofenoles/farmacología , Fotosíntesis , Hojas de la Planta/químicaRESUMEN
Aniline, a synthetic compound widely used in industrial and pesticide production, is a potential environmental pollutant. The removal of aniline is extremely important to minimize threats to human health and the surrounding environment. The objectives of this study were to investigate the removal efficiency and physiological response of Salix. babylonica cuttings to aniline pollution. Photosynthesis, chlorophyll fluorescence, spectral reflectance and the concentration of aniline in leaves, stems and roots were analysed. The experiment showed that S. babylonica has a strong removal effect on aniline wastewater. Cuttings from S. babylonica stems and roots played an important role in accumulating aniline. However, this increase in aniline concentration was dose dependent and was not always linear. With increasing aniline concentration in S. babylonica was increasingly stressed, with negative impacts on photosynthesis, chlorophyll fluorescence and spectral reflectance index in S. babylonica leaves. These results indicate that non-stomatal limitations are the main reason for the reduction in Pn in S. babylonica leaves due to chlorophyll structure destruction under aniline stress. In addition, aniline concentrations result in an unbalanced distribution of excitation energy between the two light systems, thereby hindering photosynthetic electron transfer and restricting the efficient operation of photosynthesis. Salix babylonica can endure moderate concentrations of aniline and has potential for the phyto-management of aniline-polluted wastewater, although further studies are needed using polluted wastewater.
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Compuestos de Anilina/metabolismo , Salix/metabolismo , Contaminantes Químicos del Agua/metabolismo , Biodegradación Ambiental , Clorofila/metabolismo , Fotosíntesis , Hojas de la Planta/metabolismo , Raíces de Plantas/metabolismo , Tallos de la Planta/metabolismo , Aguas Residuales/análisisRESUMEN
On-orbit radiometric calibration of the optical sensors on-board SuperView-1 satellites is the foundation for further quantitative applications. A field calibration campaign was orchestrated to radiometrically calibrate the SuperView-1 optical sensors at the Baotou calibration site in China during September 2018. Based on the collected datasets, three independent methods (reflectance-based, radiance-based, and cross-calibration) were used to determine the radiometric calibration coefficients of the SuperView-1 optical sensors with multiple permanent artificial calibration targets. Comparisons of the desert top-of-atmosphere radiance calculated based on the coefficients determined with independent methods were analyzed. Comparison results show that the minimum and maximum relative differences of the radiometrically-calibrated desert TOA radiance between the reflectance-based and radiance-based methods are 1.26% and 4.23% for SV0102 and SV0104, respectively. While, the minimum and maximum relative differences of the radiometrically-calibrated desert TOA radiance between the reflectance-based and radiance-based methods are 0.82% and 6.83% for SV0101 and SV0103, respectively. The reasonably good agreement of the radiometrically calibrated coefficients of the SuperView-1 on-board sensors between these independent methods is encouraging. An uncertainty analysis was also discussed, and the results suggest that the overall uncertainties of the predicted TOA radiance are less than 4.5%, 4.0%, and 5.15% for the reflectance-based, radiance-based, and cross-calibration methods, respectively.
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We present a physical-based atmospheric correction algorithm for land surface reflectance retrieval based on radiative transfer model MODTRAN 5, with which the aerosol optical thickness @550 nm (AOT@550nm), columnar water vapor (CWV) could also be estimated from the hyperspectral data collected over UAV platform. Then, the method was tested on both the synthetic and field campaign-collected hyperspectral data by an UAV-VNIRIS (UAV visible/near-infrared imaging hyperspectrometer) with the spectral range covering from 400 to 1000 nm. The retrieval results were validated with theoretical values from synthetic data and truth values from field campaign measurements. The results show that the averaged MAE (mean absolute error) and RMSE (root mean squared error) of measured and retrieved surface reflectance based on estimated AOT@550nm and CWV is 0.0134 and 0.0130. Meanwhile, the averaged MAE and RMSE of measured and retrieved surface reflectance based on ground measured AOT@550nm and CWV is 0.0101 and 0.0112. The results show that our introduced method has good agreement with the method based on ground-measured AOT@550nm and CWV. These encouraging results also indicate that the introduced physical-based atmospheric approach provides a quick and reliable way to acquire the land surface reflectance from UAV platform-observed hyperspectral data for further quantitative remote sensing applications.
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Hyperspectral LiDAR (HSL) technology can obtain spectral and ranging information from targets by processing the recorded waveforms and measuring the time of flight (ToF). With the development of the supercontinuum laser (SCL), it is technically easier to develop an active hyperspectral LiDAR system that can simultaneously collect both spatial information and extensive spectral information from targets. Compared with traditional LiDAR technology, which can only obtain range and intensity information at the selected spectral wavelengths, HSL detection technology has demonstrated its potential and adaptability for various quantitative applications from its spectrally resolved waveforms. However, with most previous HSLs, the collected spectral information is discrete, and such information might be insufficient and restrict the further applicability of the HSLs. In this paper, a tunable HSL technology using an acousto-optic tunable filter (AOTF) as a spectroscopic device was proposed, designed, and tested to address this issue. Both the general range precision and the accuracy of the spectral measurement were evaluated. By tuning the spectroscopic device in the time dimension, the proposed AOTF-HSL could achieve backscattered echo with continuous coverage of the full spectrum of 500-1000 nm, which had the unique characteristics of a continuous spectrum in the visible and near infrared (VNIR) regions with 10 nm spectral resolution. Yellow and green leaves from four plants (aloe, dracaena, balata, and radermachera) were measured using the AOTF-HSL to assess its feasibility in agriculture application. The spectral profiles measured by a standard spectrometer (SVC© HR-1024) were used as a reference for evaluating the measurements of the AOTF-HSL. The difference between the spectral measurements collected from active and passive instruments was minor. The comparison results show that the AOTF-based consecutive and high spectral resolution HSL was effective for this application.
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Land surface temperature (LST) is one of the key parameters in the physics of land surface processes at local/global scales. In this paper, a LST retrieval method was proposed from airborne multispectral scanner data comparing one mid-infrared (MIR) channel and one thermal infrared (TIR) channel with the land surface emissivity given as a priori knowledge. To remove the influence of the direct solar radiance efficiently, a relationship between the direct solar radiance and water vapor content and the view zenith angle and solar zenith angle was established. Then, LST could be retrieved with a split-window algorithm from MIR/TIR data. Finally, the proposed algorithm was applied to the actual airborne flight data and validated with in situ measurements of land surface types in the Baotou site in China on 17 October 2014. The results demonstrate that the difference between the retrieved and in situ LST was less than 1.5 K. The bais, RMSE, and standard deviation of the retrieved LST were 0.156 K, 0.883 K, and 0.869 K, respectively, for samples.
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Due to the lack of enough spectral bands for multi-spectral sensor, it is difficult to reconstruct surface retlectance spectrum from finite spectral information acquired by multi-spectral instrument. Here, taking into full account of the heterogeneity of pixel from remote sensing image, a method is proposed to simulate hyperspectral data from multispectral data based on canopy radiation transfer model. This method first assumes the mixed pixels contain two types of land cover, i.e., vegetation and soil. The sensitive parameters of Soil-Leaf-Canopy (SLC) model and a soil ratio factor were retrieved from multi-spectral data based on Look-Up Table (LUT) technology. Then, by combined with a soil ratio factor, all the parameters were input into the SLC model to simulate the surface reflectance spectrum from 400 to 2 400 nm. Taking Landsat Enhanced Thematic Mapper Plus (ETM+) image as reference image, the surface reflectance spectrum was simulated. The simulated reflectance spectrum revealed different feature information of different surface types. To test the performance of this method, the simulated reflectance spectrum was convolved with the Landsat ETM + spectral response curves and Moderate Resolution Imaging Spectrometer (MODIS) spectral response curves to obtain the simulated Landsat ETM+ and MODIS image. Finally, the simulated Landsat ETM+ and MODIS images were compared with the observed Landsat ETM+ and MODIS images. The results generally showed high correction coefficients (Landsat: 0.90-0.99, MODIS: 0.74-0.85) between most simulated bands and observed bands and indicated that the simulated reflectance spectrum was well simulated and reliable.
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Monitoreo del Ambiente/métodos , Hojas de la Planta , Imágenes Satelitales , Análisis Espectral/métodosRESUMEN
While the forests on Mount Taishan are predominantly man-made, there is a notable vertical variation in vegetation. This study employs the method of cloud model, quantifying uncertainty (fuzziness and randomness) of things. Utilizing digital elevation model (DEM) and vegetation distribution data, we constructed elevation cloud models for Mount Taishan's deciduous broad-leaved, temperate coniferous, and mixed coniferous-broadleaved forests. Using three numerical features of the cloud model-Expectation (EX), Entropy (EN), and Hyper-entropy (HE)-we quantitatively analyzed the macro regularity and local heterogeneity of Mount Taishan's forests vertical distribution from the perspective of uncertainty theory. The results indicate: (1) The EX of the core zone elevation of deciduous broad-leaved forest is 716.65 m, temperate coniferous forest is 1053.51 m, and mixed coniferous-broadleaved forest is 1384.09 m. The variation range of the core zone distribution height is smaller in the mixed coniferous-broadleaved forest (EN: 53.74 m) compared to deciduous broad-leaved forest (EN: 99.63 m) and temperate coniferous forest (EN: 121.70 m). (2) The fuzziness and randomness of the distribution height of the lower extension zones of deciduous broad-leaved forest and temperate coniferous forest (EN: 75.15 m, 184.56 m; HE: 24.09 m, 63.54 m) are greater than those of the upper extension zones (EN: 44.75 m, 42.49 m; HE: 14.48 m, 13.23 m). (3) The distribution fuzziness and randomness within temperate coniferous forests exceed those of deciduous broad-leaved forests. Within the core zones, the uncertainty regarding the vertical distribution of vegetation across different aspects remains consistent, which retains the characteristic of man-made forests. However, in transition areas, there is significant disparity, reflecting the adaptive relationship between vegetation and its environment to some extent. In the upper and lower extension zones of deciduous broad-leaved forests, the EX values for the vertical distribution height of mixed coniferous and broad-leaved forests differ significantly from those of deciduous broad-leaved forests (the difference is 22.82-39.15 m), yet closely resemble those of temperate coniferous forests (the difference is 4.79-7.94 m). This suggests a trend wherein deciduous broad-leaved tree species exhibit a proclivity to encroach upon coniferous forest habitats. The elevation cloud model of vertical vegetation zones provides a novel perspective and method for the detailed analysis of Mount Taishan's vegetation vertical differentiation.
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Bosques , China , Modelos Teóricos , Árboles/crecimiento & desarrollo , Tracheophyta/crecimiento & desarrollo , EcosistemaRESUMEN
2,4-Dinitrophenol (2,4-DNP) is recognized as an emerging contaminant due to its high toxicity and poor biodegradability, posing a threat to animals, plants, and human health. The efficient removal of 2,4-DNP remains a challenging issue in phytoremediation research, particularly because of its toxic effects on plants. To address this, a hydroponic simulation experiment was conducted to investigate the impact of adding exogenous methyl jasmonate (MeJA) on the tolerance and purification capabilities of Salix matsudana Koidz (S. matsudana) seedlings exposed to 2,4-DNP. The results indicated that the addition of exogenous MeJA mitigated the damage caused by 2,4-DNP to S. matsudana seedlings by enhancing the activity of antioxidant enzymes, reducing excess reactive oxygen species (ROS), lowering membrane lipid peroxidation, and minimizing membrane damage. Notably, the most effective alleviation was observed with the addition of 50 mg·L-1 MeJA. Furthermore, exogenous MeJA helped maintain the biomass indices of S. matsudana seedlings under 2,4-DNP stress and increased the removal efficiency of 2,4-DNP by these seedlings. Specifically, the addition of 50 mg·L-1 MeJA resulted in a removal percentage of 79.57%, which was 11.88% higher than that achieved with 2,4-DNP treatment. In conclusion, exogenous MeJA can improve the plant resistance and enhance 2,4-DNP phytoremediation.
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Biodegradación Ambiental , Ciclopentanos , Oxilipinas , Salix , Aguas Residuales , Salix/efectos de los fármacos , Aguas Residuales/química , 2,4-Dinitrofenol , Acetatos , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Peanut root rot, commonly referred to as rat tail or root rot, is caused by a range of Fusarium species. A strain of bacteria (named TG5) was isolated from crop rhizosphere soil in Mount Taishan, Shandong Province, China, through whole genome sequencing that TG5 was identified as Bacillus thuringiensis, which can specifically produce chloramphenicol, bacitracin, clarithromycin, lichen VK21A1 and bacitracin, with good biological control potential. Based on liquid chromatography tandem mass spectrometry metabonomics analysis and transcriptome conjoint analysis, the mechanism of TG5 and carbendazim inducing peanut plants to resist F. oxysporum stress was studied. In general, for peanut root rot caused by F. oxysporum, B. thuringiensis TG5 has greater advantages than carbendazim and is environmentally friendly. These findings provide new insights for peanut crop genetics and breeding, and for microbial pesticides to replace traditional highly toxic and highly polluting chemical pesticides. Based on the current background of agricultural green cycle and sustainable development, it has significant practical significance and broad application prospects.
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Introduction: To clarify the effects of microtopography on plant growth and soil water, salt and nutrient characteristics of saline soils in mudflats within muddy coastal zones and explore suitable microtopographic modifications. Methods: Six microtopographic modification patterns, namely, S-shaped, stripe-shaped, pin-shaped, stepshaped, dense stripe-shaped and crescent-shaped patterns, were established in the coastal mudflats of the Yellow River Delta. The soil water, salt, ion, total carbon, total nitrogen, and total phosphorus contents and their ecological stoichiometric characteristics were measured and analyzed after theimplementation of different microtopographic modification patterns, with bare mudflats as the control. Results: The results showed that microtopographic modification significantly changed the soil water and salt contents and the soil total carbon, total nitrogen and total phosphorus contents. Compared with the bare ground, microtopographic transformation significantly promoted the growth of the pioneer plant Suaeda salsa, significantly increased the soil water and nutrient contents, and significantly decreased the soil salinity. The soil salinity was mainly reduced by Na+ and Cl- ions. The soil salinity and nutrient contents gradually decreased with increasing soil depth, indicating the occurrence of surface aggregation. Compared to that of the bare ground, the soil C/N was significantly lower and the N/P was significantly higher in the microtopographic treatments, and the overall performance suggested soil N limitation. The ions contained in the saline soil were dominated by Na+ and Cl-, followed by Mg2+ and SO4 2-, with lower contents of K+, Ca2+ and HCO3 -. Among the six microtopography modification patterns, the crescent-shaped pattern best promoted vegetation restoration. This pattern was the most effective in reducing soil salinity, with a 98.53% reduction in soil salinity compared with that of bare ground, followed by the pin-shaped pattern. Compared with that in the bare ground samples, the nutrient content in the samples from the step-shaped modification increased by 23.27%; finally, the S-shaped, step-shaped and dense stripe-shaped patterns performed poorly in terms of plant restoration and soil improvement. Discussion: It is suggested that a crescent-shaped pattern should be considered first when carrying out microtopographic transformation on the beaches of the Yellow River Delta, followed by stripe-shaped and pin-shaped patterns. The dense strip-shaped should not be adopted.
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Forest soils are important components of forest ecosystems, and soil quality assessment as a decision-making tool to understand forest soil quality and maintain soil productivity is essential. Various methods of soil quality assessment have been developed, which have occasionally generated inconsistent assessment results between soil types. We assessed the soil quality of five communities (herb, shrub, Quercus acutissima, Pinus thunbergii, and Q. acutissima-P. thunbergii mixed plantation) using two common methods of dry and barren mountains in the Yimeng Mountain area, China. Sixteen soil physical, chemical and biological properties were analysed. The soil quality index was determined using the established minimum data set based on the selection results of principal component analysis and Pearson analysis. Silt, soil total phosphorus (P), soil total nitrogen (N), L-leucine aminopeptidase, acid phosphatase and vector length were identified as the most representative indicators for the minimum data set. Linear regression analysis showed that the minimum data set can adequately represent the total data set to quantify the impact of different communities on soil quality (P < 0.001). The results of linear and non-linear methods of soil quality assessment showed that the higher soil quality index was Pinus forest (0.59 and 0.54), and the soil quality index of mixed plantation (0.41 and 0.45) was lower, which was similar to the herb community (0.37 and 0.44). Soil quality was mostly affected by soil chemical properties and extracellular enzyme activities of different communities, and the different reasons for the low soil quality of mixed plantations were affected by soil organic carbon (C) and total C. Overall, we demonstrate that the soil quality index based on the minimum data set method could be a useful tool to indicate the soil quality of forest systems. Mixed plantations can improve soil quality by increasing soil C, which is crucial in ecosystem balance.
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Ecosistema , Pinus , Suelo/química , Carbono/análisis , Bosques , China , Nitrógeno/análisisRESUMEN
Two new lignans, named zuihonins E (1) and F (2), were isolated from the stems of Schisandra bicolor Cheng var. tuberculata Law. The structures of the new lignans were elucidated on the basis of extensive spectroscopic analysis, including 1D, 2D NMR, and MS experiments, and their absolute stereochemistry was determined by circular dichroism spectrum. Compounds 1 and 2 did not inhibit the growth of hepatoma carcinoma cell (HepG2), lung carcinoma cell (A549), and human breast carcinoma (MCF-7) cell lines.
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Lignanos/aislamiento & purificación , Schisandra/química , Ensayos de Selección de Medicamentos Antitumorales , Femenino , Células Hep G2 , Humanos , Lignanos/química , Lignanos/farmacología , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Tallos de la Planta/químicaRESUMEN
Ulmus parvifolia (U. parvifolia) is a Chinese medicine plant whose bark and leaves are used in the treatment of some diseases such as inflammation, diarrhea and fever. However, metabolic signatures of seeds have not been studied. The seeds and bark of U. parvifolia collected at the seed ripening stage were used for metabolite profiling analysis through the untargeted metabolomics approach. A total of 2,578 and 2,207 metabolites, while 503 and 132 unique metabolites were identified in seeds and bark, respectively. Additionally, 574 differential metabolites (DEMs) were detected in the two different organs of U. parvifolia, which were grouped into 52 classes. Most kinds of metabolites classed into prenol lipids class. The relative content of flavonoids class was the highest. DEMs contained some bioactive compounds (e.g., flavonoids, terpene glycosides, triterpenoids, sesquiterpenoids) with antioxidant, anti-inflammatory, and anti-cancer activities. Most kinds of flavonoids and sesquiterpenes were up-regulated in seeds. There were more varieties of terpene glycosides and triterpenoids showing up-regulated in bark. The pathway enrichment was performed, while flavonoid biosynthesis, flavone and flavonol biosynthesis were worthy of attention. This study identified DEMs with pharmaceutical value between seeds and bark during seed maturation and offered a molecular basis for alternative or complementary use of seeds and bark of U. parvifolia as a Chinese medicinal material.
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Triterpenos , Ulmus , Ulmus/metabolismo , Corteza de la Planta/metabolismo , Medicina Tradicional China , Extractos Vegetales , Semillas/metabolismo , Flavonoides/metabolismo , Glicósidos/metabolismo , Triterpenos/metabolismo , Terpenos/metabolismoRESUMEN
A number of strict lockdown measures were implemented in the areas most affected by COVID-19 in China, including Ji'nan city, from 24 January to 7 February 2020. Due to these forced restrictions, the pollution levels in cities across the country drastically decreased within just a few days. Since traffic pollution and industrial emissions are important factors affecting regional air quality, congestion has a significant impact on the environment. Therefore, using the aid of air quality data for six pollutants (PM10, PM2.5, SO2, NO2, CO and O3) from 11 monitoring stations (located in urban, suburban and urban-industrial regions) across Ji'nan, we employed the air quality index (AQI) to investigate the spatial pattern of air quality in the pre-COVID-19 (pre-COVID) and COVID-19-related lockdown (COVID lockdown) periods. The results showed that air quality significantly improved during the COVID lockdown period. Among the selected pollutants, compared to the corresponding pre-COVID levels, the greatest reduction was observed for the concentration of NO2 (54.02%), while the smallest reduction was observed for the concentration of SO2 (27.92%). The PM2.5 (38.73%), PM10 (44.92%) and CO (30.60%) levels also decreased during the COVID lockdown period; only the O3 concentration increased (37.42%) during this period. Overall, air quality improved by approximate improvements of 37.33% during the COVID lockdown period. Approximately 35.48%, 37.01% and 43.43% in the AQI were observed in urban, suburban and urban-industrial regions, respectively. Therefore, the AQI exhibited remarkable regional differences in Ji'nan. This study demonstrates the contributions of the transportation sector and local emissions to improving air quality in typical urban areas, and these research results can provide guidance for the further monitoring of air pollution in northern Chinese cities.
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Contaminantes Atmosféricos , Contaminación del Aire , COVID-19 , Contaminantes Ambientales , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Animales , COVID-19/epidemiología , COVID-19/prevención & control , China/epidemiología , Ciudades/epidemiología , Control de Enfermedades Transmisibles , Monitoreo del Ambiente , Caballos , Dióxido de Nitrógeno/análisis , Material Particulado/análisis , SARS-CoV-2RESUMEN
Canopy chlorophyll content (CCC) indicates the photosynthetic functioning of a crop, which is essential for the growth and development and yield increasing. Accurate estimation of CCC from remote-sensing data benefits from including information on leaf chlorophyll and canopy structures. However, conventional nadir reflectance is usually subject to the lack of an adequate expression on the geometric structures and shaded parts of vegetation canopy, and the derived vegetation indices (VIs) are prone to be saturated at high CCC level. Using 3-year field experiments with different wheat cultivars, leaf colors, structural types, and growth stages, and integrated with PROSPECT+SAILh model simulation, we studied the potential of multi-angle reflectance data for the improved estimation of CCC. The characteristics of angular anisotropy in spectral reflectance were investigated. Analyses based on both simulated and experimental multi-angle hyperspectral data were carried out to compare performances of 20 existing VIs at different viewing angles, and to propose an algorithm to develop novel biangular-combined vegetation indices (BCVIs) for tracking CCC dynamics in wheat. The results indicated that spectral reflectance values, as well as the coefficient of determination (R 2) between mono-angular VIs and CCC, at back-scattering directions, were mostly higher than those at forward-scattering directions. Mono-angular VIs at +30° angle, were closest to the hot-spot position in our case, achieved the highest R 2 among 13 viewing angles including the nadir observation. The general formulation for the newly developed BCVIs was BCVIVI = f × VI(θ1) - (1 - f) × VI(θ2), in which the VI was used to characterize chlorophyll status, while the subtraction of VI at θ1 and θ2 viewing angles in a proportion was used to highlight the canopy structural information. From our result, the values of the θ1 and θ2 around hot-spot and dark-spot positions, and the f of 0.6 or 0.7 were found as the optimized values. Through comparisons revealed that large improvements on CCC modeling could be obtained by the BCVIs, especially for the experimental data, indicated by the increase in R 2 by 25.1-51.4%, as compared to the corresponding mono-angular VIs at +30° angle. The BCVIMCARI[705,750] was proved to greatly undermine the saturation effect of mono-angular MCARI[705,750], expressing the best linearity and the most sensitive to CCC, with R 2 of 0.98 and 0.72 for simulated and experimental data, respectively. Our study will eventually have extensive prospects in monitoring crop phenotype dynamics in for example large breeding trials.
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Phyllosphere bacteria are an important component of environmental microbial communities and are closely related to plant health and ecosystem stability. However, the relationships between the inhabitation and assembly of phyllosphere bacteria and leaf microtopography are still obscure. In this study, the phyllosphere bacterial communities and leaf microtopographic features (vein density, stomatal length, and density) of eleven tree species were fully examined. Both the absolute abundance and diversity of phyllosphere bacterial communities were significantly different among the tree species, and leaf vein density dominated the variation. TITAN analysis showed that leaf vein density also played more important roles in regulating the relative abundance of bacteria than stomatal features, and 6 phyla and 62 genera of phyllosphere bacteria showed significant positive responses to leaf vein density. Moreover, LEfSe analysis showed that the leaves with higher vein density had more bacterial biomarkers. Leaf vein density also changed the co-occurrence pattern of phyllosphere bacteria, and the co-occurrence network demonstrated more negative correlations and more nodes on the leaves with larger leaf vein density, indicating that higher densities of leaf veins improved the stability of the phyllosphere bacterial community. Phylogenetic analysis showed that deterministic processes (especially homogeneous selection) dominated the assembly process of phyllosphere bacterial communities. The leaf vein density increased the degree of bacterial clustering at the phylogenetic level. Therefore, the inhabitation and assembly of the phyllosphere bacterial community are related to leaf microtopography, which provides deeper insight into the interaction between plants and bacteria.
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Bacterias , Ecosistema , Microbiota , Hojas de la Planta , Árboles , Bacterias/clasificación , Bacterias/genética , Biodiversidad , Filogenia , Hojas de la Planta/microbiología , Árboles/microbiologíaRESUMEN
To explore the adaptation of the fine root morphology and chemical characteristics of Tamarix chinensis to water-salt heterogeneity in the groundwater-soil system of a coastal wetland zone, T. chinensis forests at different groundwater levels (high: GW1 0.54 m and GW2 0.83 m; medium: GW3 1.18 m; low: GW4 1.62 m and GW5 2.04 m) in the coastal wetland of the Yellow River Delta were researched, and the fine roots of T. chinensis standard trees were excavated. The fine roots were classified by the Pregitzer method, and the morphology, nutrients, and nonstructural carbohydrate characteristics of each order were determined. The results showed that the groundwater level had a significant indigenous effect on the soil water and salt conditions and affected the fine roots of T. chinensis. At high groundwater levels, the specific root length and specific surface area of fine roots were small, the root tissue density was high, the fine root growth rate was slow, the nutrient use efficiency was higher than at low groundwater levels, and the absorption of water increased with increasing specific surface area. With decreasing groundwater level, the N content and C/N ratio of fine roots first decreased and then increased, and the soluble sugar, starch, and nonstructural carbohydrate content of fine roots first increased and then decreased. At high and low groundwater levels, the metabolism of fine roots of T. chinensis was enhanced, and their adaptability to high salt content and low water content soil environments improved. The first- and second-order fine roots of T. chinensis were mainly responsible for water and nutrient absorption, while the higher-order (from the third to fifth orders) fine roots were primarily responsible for the transportation and storage of carbohydrates. The fine root morphology, nutrients, nonstructural carbohydrate characteristics, and other aspects of the water and salt environment heterogeneity cooperated in a synergistic response and trade-off adjustment.