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1.
Mar Pollut Bull ; 203: 116382, 2024 Apr 27.
Article En | MEDLINE | ID: mdl-38678739

This study comprehensively assesses spatial distribution, pollution levels, and potential sources of heavy metal(loid)s in surface sediments across multiple river systems along the coastal area of the East China Sea. Copper in Qiantang River and Xiangshan Bay showed higher concentations and exceeded the threshold effect value, while the higher content of Lead was mainly found in the Saijiang River, Oujiang River, and Minjiang River. Heavy metal(loid)s in the alluvium of Qiantang River, Jiaojiang River, and Yangtze River showed low to moderate pollution levels, with Cd posing the highest ecological risk, followed by Hg. Meanwhile, Qiantang River, Jiaojiang River, Yangtze River, and Oujiang River exhibited considerable to moderate ecological risks and low toxic risk. PMF model analysis results reveal that concentrations of Cr, Ni, and As were closely related with natural geogenic input (36.56 %), while industrial and traffic activities (48.77 %) were primary source of Cu, Pb, Zn, and Hg, and main source of Cd was agricultural emissions (14.67 %).

2.
J Colloid Interface Sci ; 668: 68-76, 2024 Aug 15.
Article En | MEDLINE | ID: mdl-38669997

Two-dimensional (2D) CsPbBr3 nanoplatelets (NPLs) have attracted great attention as one of promising semiconductor nanomaterials due to their large exciton binding energy and narrow emission spectra. However, the labile ionic and weakly bound surfaces of deep-blue emitting CsPbBr3 NPLs with wide bandgap result in their colloidal instability, thus degrading their optical properties. It is challenging to obtain deep-blue emitting CsPbBr3 NPLs with excellent optical properties. In this study, high-quality blue-emitting CsPbBr3 NPLs with tunable thickness were prepared adopting the DBSA-mediated confinement effect based on the hot-injection method. Thanks to the coordination interaction of - SO3- of DBSA ligand and the Pb2+ on the surface of the CsPbBr3 NPLs, as well as the effective passivation of Br vacancy defects on the surface of NPLs by OAm-Br, the obtained pure-blue CsPbBr3 NPLs and deep-blue CsPbBr3 NPLs show high photoluminescence quantum yield (PLQY) of 92 % and 81.2 %, respectively. To the best of our knowledge, this is the highest PLQY recorded for deep-blue emitting CsPbBr3 NPLs with two monolayers [PbBr6]4- octahedra. Furthermore, the agglomeration of CsPbBr3 NPLs due to ligand loss induced by moisture, oxygen, and irradiation was also suppressed by the dual passivation effect of DBSA and OAm-Br. Our work provided a new approach to developing high-performance and stable deep-blue emitting CsPbBr3 perovskite nanoplatelets.

3.
Front Microbiol ; 15: 1347821, 2024.
Article En | MEDLINE | ID: mdl-38601935

The impact of climate warming on soil microbial communities can significantly influence the global carbon cycle. Coastal wetlands, in particular, are susceptible to changes in soil microbial community structure due to climate warming and the presence of invasive plant species. However, there is limited knowledge about how native and invasive plant wetland soil microbes differ in their response to warming. In this study, we investigated the temporal dynamics of soil microbes (prokaryotes and fungi) under experimental warming in two coastal wetlands dominated by native Phragmites australis (P. australis) and invasive Spartina alterniflora (S. alterniflora). Our research indicated that short-term warming had minimal effects on microbial abundance, diversity, and composition. However, it did accelerate the succession of soil microbial communities, with potentially greater impacts on fungi than prokaryotes. Furthermore, in the S. alterniflora wetland, experimental warming notably increased the complexity and connectivity of the microbial networks. While in the P. australis wetland, it decreased these factors. Analysis of robustness showed that experimental warming stabilized the co-occurrence network of the microbial community in the P. australis wetland, but destabilized it in the S. alterniflora wetland. Additionally, the functional prediction analysis using the Faprotax and FunGuild databases revealed that the S. alterniflora wetland had a higher proportion of saprotrophic fungi and prokaryotic OTUs involved in carbon degradation (p < 0.05). With warming treatments, there was an increasing trend in the proportion of prokaryotic OTUs involved in carbon degradation, particularly in the S. alterniflora wetland. Therefore, it is crucial to protect native P. australis wetlands from S. alterniflora invasion to mitigate carbon emissions and preserve the health of coastal wetland ecosystems under future climate warming in China.

4.
Ying Yong Sheng Tai Xue Bao ; 34(7): 1825-1833, 2023 Jul.
Article En | MEDLINE | ID: mdl-37694466

Coastal wetlands are highly efficient in blue carbon sequestration. The impacts of climate warming on photosynthetic rates and light response characteristics of wetland plants would change the magnitude of carbon sequestration in coastal wetlands. We constructed warming observation stations in Phragmites australis (Phragmites) wetlands located in the Yellow River Delta in Dongying with dry climate, and in Yancheng by the Yellow Sea with wet climate. By using a Li-6800 photosynthesis system, we investigated the responses of simulated warming on photosynthetic characteristics of Phragmites in both wetlands, and compared the difference between months (June and August) in Dongying wetland. The results showed the photosynthetic rates of Phragmites were higher in June than in August. Warming increased net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (gs) and intercellular carbon dioxide concentration (Ci) in the two months, but the variability of Pn to warming was lower in August. The Pn and water use efficiency (WUE) of Phragmites in the Yancheng wetland were higher than Dongying wetland, and the maximum net photosynthetic rate (Pn max), light saturation point (LSP), apparent quantum efficiency (AQY), and dark respiration rate (Rd) of the former responded more positively to warming. The values of AQY, LSP and Pn max of Phragmites in the Yancheng wetlands were increased by 16.7%, 53.6% and 30.3%, respectively, in the warming plots. Our results suggested that warming could improve the utilization efficiency of weak light, the adaptability to strong light and photosynthetic potential of Phragmites under rainy and humid conditions. This study is of importance for accurately quantifying carbon sequestration of coastal wetlands at the regional and seasonal scales in the context of climate warming.


Poaceae , Wetlands , China , Biological Transport , Photosynthesis
5.
Inorg Chem ; 62(38): 15641-15650, 2023 Sep 25.
Article En | MEDLINE | ID: mdl-37690055

When it comes to an efficient catalytic oxygen evolution reaction (OER) in the production of renewable energy and chemicals, the construction of heterogeneous structures is crucial to break the linear scalar relationship of a single catalyst. This heterogeneous structure construction helps creatively achieve high activity and stability. However, the synthesis process of heterogeneous crystalline materials is often complex and challenging to capture and reproduce, which limits their application. Here, the dynamic process of structural changes in Co-MOFs in alkali was captured by in situ powder X-ray diffraction, FT-IR spectroscopy, and Raman spectroscopy, and several self-reconfigured MOF heterogeneous materials with different structures were stably isolated. The created ß-Co(OH)2/Co-MOF heterojunction structure facilitates rapid mass-charge transfer and exposure of active sites, which significantly enhanced OER activity. Experimental results show that this heterogeneous structure achieves a low overpotential of 333 mV at 10 mA cm-2. The findings provide new insights and directions for the search for highly reactive cobalt-based MOFs for sustainable energy technologies.

6.
ACS Appl Mater Interfaces ; 15(22): 26910-26917, 2023 Jun 07.
Article En | MEDLINE | ID: mdl-37246367

Graphdiyne (GDY) has realized significant achievements in lithium-ion batteries (LIBs) because of its unique π-conjugated skeleton with sp- and sp2-hybridized carbon atoms. Enriching the accessible surface areas and diffusion pathways of Li ions can realize more storage sites and rapid transport dynamics. Herein, three-dimensional porous hydrogen-substituted GDY (HsGDY) is developed for high-performance Li-ion storage. HsGDY, fabricated via a versatile interface-assisted synthesis strategy, exhibits a large specific surface area (667.9 m2 g-1), a hierarchical porous structure, and an expanded interlayer space, which accelerate Li-ion accessibility and lithiation/delithiation. Owing to this high π-conjugated, conductive, and porous framework, HsGDY exhibits a large reversible capacity (930 mA h g-1 after 100 cycles at 1 A g-1), superior cycle (720 mA h g-1 after 300 cycles at 1 A g-1), and rate (490 mA h g-1 at 5 A g-1) performances. Density functional theory calculations of the low diffusion barrier in the lamination and vertical directions further reveal the fast Li-ion transport kinetics of HsGDY. Additionally, a LiCoO2-HsGDY full cell is constructed, which exhibits a good practical charge/discharge capacity of 128 mA h g-1 and stable cycling behavior. This study highlights the advanced design of next-generation LIBs to sustainably develop the new energy industry.

7.
ACS Biomater Sci Eng ; 9(6): 3402-3413, 2023 06 12.
Article En | MEDLINE | ID: mdl-37140447

Current anticancer research shows that a combination of multiple treatment methods can greatly improve the killing of tumor cells. Using the latest microfluidic swirl mixer technology, combined with chemotherapy and photothermal-ablation therapy, we developed multiresponsive targeted antitumor nanoparticles (NPs) made of folate-functionalized gelatin NPs under 200 nm in size and with encapsulated CuS NPs, Fe3O4 NPs, and curcumin (Cur). By exploring gelatin's structure, adjusting its concentration and pH, and fine-tuning the fluid dynamics in the microfluidic device, the best preparation conditions were obtained for gelatin NPs with an average particle size of 90 ± 7 nm. The comparative targeting of the drug delivery system (DDS) was demonstrated on lung adenocarcinoma A549 cells (low level of folate receptors) and breast adenocarcinoma MCF-7 cells (high level of folate receptors). Folic acid helps achieve targeting and accurate delivery of NPs to the MCF-7 tumor cells. The synergistic photothermal ablation and curcumin's anticancer activity are achieved through infrared light irradiation (980 nm), while Fe3O4 is guided with an external magnetic field to target gelatin NPs and accelerate the uptake of drugs, thus efficiently killing tumor cells. The method described in this work is simple, easy to repeat, and has great potential to be scaled up for industrial production and subsequent clinical use.


Antineoplastic Agents , Curcumin , Nanoparticles , Humans , Curcumin/pharmacology , Curcumin/chemistry , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Gelatin , Microfluidics , Nanoparticles/chemistry , Folic Acid
8.
Angew Chem Int Ed Engl ; 62(20): e202301618, 2023 May 08.
Article En | MEDLINE | ID: mdl-36916126

Fiber-shaped supercapacitors (FSCs) have become one of the significantly strategical flexible energy-storage materials towards future wearable textile electronics and metaverse technologies. Here, we develop the high-performance FSCs based on multiscale dot-wire-sheet heterostructure microfiber of nitrogen-doped carbon dots-Ti3 C2 Tx /silk nanofibers (NCDs-Ti3 C2 Tx /SNFs) hybrids via microfluidic fabrication. Due to the enlarged interlayer spacing, plentiful porous channels, accelerated H+ ion transport dynamics, large electrical conductivity and excellent mechanical strength/flexibility, the NCDs-Ti3 C2 Tx /SNFs possesses high volumetric capacitance (2218.7 F cm-3 ) and reversible charge-discharge stability in 1 M H2 SO4 electrolyte. Furthermore, the solid-state FSCs present high energy density (57.9 mWh cm-3 ), good capacitance (1157 F cm-3 ), long-life cycles (82.3 % capacitance retention after 40000 cycles), which realize the actual energy-supply applications (powering lamp, watch and toy car).

9.
Environ Sci Pollut Res Int ; 30(7): 18843-18860, 2023 Feb.
Article En | MEDLINE | ID: mdl-36219297

Studies of heavy metal pollution are essential for the protection of coastal environments. In this study, positive matrix factorization (PMF) and a GeoDetector model were used to evaluate the sources of heavy metal contamination and associated ecological risks along the Yancheng Coastal Wetland. The distribution of heavy metals was shown to be greatly affected by clay content, except for Cr in shoal. Components from 6.5 to 9φ have the strongest ability to absorb heavy metals, where the effects of Cd and Zn sequestration in the wetlands were most apparent. The abilities of various wetland environments to sequester heavy metals were shown to be Spartina alterniflora wetland > woodland > Phragmites australis wetland > aquaculture pond > shoal > paddy > meadow > dry land. The sources of the heavy metals included parent soil material (59%), agriculture (15%), and industrial pollutants (26%). According to the single-factor pollution index, there was no evidence of pollution except Cr and Pb. In general, the heavy metal pollution was insignificant. The order of pollution loading index was shoal > paddy field > dry land > Spartina Alterniflora wetland > aquaculture ponds > woodland > meadow > Phragmites australis wetland. The ecological harm of heavy metal exposure was slight except for Cd and Hg, where vehicle emissions appeared to be the main cause of heavy metal pollution.


Metals, Heavy , Soil Pollutants , Ecosystem , Soil , Cadmium , Soil Pollutants/analysis , Environmental Monitoring , Risk Assessment , Metals, Heavy/analysis , Poaceae , China
10.
Adv Biol (Weinh) ; 7(2): e2200201, 2023 02.
Article En | MEDLINE | ID: mdl-36394211

Liquid biopsy has been taken as a minimally invasive examination and a promising surrogate to the clinically applied tissue-based test for the diagnosis and molecular analysis of cancer. Extracellular vesicles (EVs) carry complex molecular information from the tumor, allowing for the multicomponent analysis of cancer and would be beneficial to personalized medicine. In this review, the advanced nanomaterials and nanotechniques for the detection and molecular profiling of EVs, highlight the advantages of nanotechnology in the high-purity isolation and the high-sensitive and high-specific identification of EVs, are summarized. An outlook on the clinical application of nanotechnology-based liquid biopsy in the diagnosis, prognostication, and surveillance of cancer is also provided. It provides information for developing liquid biopsy based on EVs by discussing the advantages and challenges of functionalized nanomaterials and various nanotechnologies.


Extracellular Vesicles , Nanostructures , Neoplasms , Humans , Biomarkers, Tumor , Extracellular Vesicles/pathology , Nanotechnology , Neoplasms/diagnosis
11.
Inorg Chem ; 61(46): 18743-18751, 2022 Nov 21.
Article En | MEDLINE | ID: mdl-36356227

Basic requirements for advanced and practical supercapacitors need electrode materials with strong stability, high surface area, well-defined porosity, and enhanced capability of ion insertion and electron transfer. It is worth mentioning that the two-dimensional cluster-based Ni/Co-organic layer (Ni0.7Co0.3-CMOL) inherits high stability from the Kagóme lattice and shows excellent pseudocapacitance behavior. As an optimized atomic composition, this crystalline CMOL exhibits excellent performance and stability both in 1.0 M KOH and All-Solid-State Flexible Asymmetric Supercapacitor (ASCs). The specific capacitance values are 1211 and 394 F g-1 and the energy density is 54.67 Wh kg-1 at 1 A g-1. Good cycling stability is characterized by its capacitance retention, maintained at 92.4% after 5000 cycles in a three-electrode system and 90% after 2000 cycles at 20 A g-1 for assembled All-Solid-State Flexible ASCs. An in situ XRD technique was used in the three-electrode system, which showed that there was no signal of crystalline substance that affected the cyclic stability of the material while charging and discharging. These superior results prove that Ni0.7Co0.3-CMOL is a promising candidate for supercapacitor applications.

12.
J Am Chem Soc ; 144(44): 20278-20287, 2022 11 09.
Article En | MEDLINE | ID: mdl-36288475

Protein heterogeneity in molecular expression and structures determines tumorigenesis and is the diagnostic and therapeutic cancer biomarker. Small extracellular vesicles (sEVs) are cell-released nanoscaled membrane-bound vesicles transferring bioactive molecules for intercellular communication and playing essential roles in tumor progression and metastasis. Therefore, protein heterogeneity in tumor-derived sEVs indicates the degree of malignant transformation, providing a noninvasive biomarker for cancer diagnosis and malignancy evaluation. We employ near-field infrared (nano-FTIR) spectroscopy to investigate malignancy-related protein heterogeneity in a single sEV and demonstrate the discriminability of sEV protein heterogeneity to evaluate tumor malignancy and metastasis. We found that the amide I/II adsorption ratio of the sEVs increases with tumor malignancy, the proportion of α-helix + random coil (α-helix and random coil) in sEV proteins decreases with tumor malignancy, and the proportion of ß-sheet + ß-turn (ß-sheet and ß-turn) increases with tumor malignancy. These nano-FTIR spectral signatures of the sEVs from the primary tumor tissue of breast cancer patients show high sensitivity and specificity in evaluating tumor metastasis. This study shows the advantages of nano-FTIR in single sEV characterization and demonstrates the significance of sEV protein heterogeneity in cancer diagnosis. It provides a noninvasive solution to elucidate cancer development and facilitates the exploitation of potential cancer biomarkers.


Extracellular Vesicles , Neoplasms , Humans , Extracellular Vesicles/metabolism , Neoplasms/diagnosis , Neoplasms/metabolism , Biomarkers, Tumor/metabolism
13.
Int J Pharm ; 622: 121857, 2022 Jun 25.
Article En | MEDLINE | ID: mdl-35623489

Liposomes have been widely used in nanomedicine for the delivery of hydrophobic and hydrophilic anticancer agents. The most common applications of these formulations are vaccines and anticancer formulations (e.g., mRNA, small molecule drugs). However, large-scale production with precise control of size and size distribution of the lipid-based drug delivery systems (DDSs) is one of the major challenges in the pharmaceutical industry. In this study, we used newly designed microfluidic swirl mixers with simple 3D mixing chamber structures to prepare liposomes at a larger scale (up to 320 mL/min or 20 L/h) than the commercially available devices. This design demonstrated high productivity and better control of liposome size and polydispersity index (PDI) than conventional liposome preparation methods. The microfluidic swirl mixer devices were used to produce curcumin-loaded liposomes under different processing conditions which were later characterized and studied in vitro to evaluate their efficiency as DDSs. The obtained results demonstrated that the liposomes can effectively deliver curcumin into cancer cells. Therefore, the microfluidic swirl mixers are promising devices for reproducible and scalable manufacturing of DDSs.


Curcumin , Neoplasms , Drug Delivery Systems , Liposomes/chemistry , Microfluidics/methods , Nanomedicine , Particle Size
14.
Nanomaterials (Basel) ; 12(5)2022 Feb 28.
Article En | MEDLINE | ID: mdl-35269297

Small extracellular vesicles (sEVs) carry molecular information from their source cells and are desired biomarkers for cancer diagnosis. We establish a machine learning-assisted dual-marker detection method to analyze the expression of epidermal growth factor receptor (EGFR) and C-X-C chemokine receptor 4 (CXCR4) in serum sEVs for the diagnosis and prognosis prediction of non-small cell lung cancer (NSCLC). We find that the serum sEV EGFR and CXCR4 are significantly higher in advanced stage NSCLC (A/NSCLC) patients compared to early stage NSCLC (E/NSCLC) patients and the healthy donors (HDs). A receiver operating characteristic curve (ROC) analysis demonstrates that the combination of EGFR and CXCR4 in serum sEVs as an efficient diagnostic index and malignant degree indicator for NSCLC. Machine learning further shows a diagnostic accuracy of 97.4% for the training cohort and 91.7% for the validation cohort based on the combinational marker. Moreover, this machine leaning-assisted serum sEV analysis successfully predicts the possibility of tumor relapse in three NSCLC patients by comparing their serum sEVs before and three days after surgery. This study provides an intelligent serum sEV-based assay for the diagnosis and prognosis prediction of NSCLC, and will benefit the precision management of NSCLC.

15.
Chembiochem ; 23(8): e202200048, 2022 04 20.
Article En | MEDLINE | ID: mdl-35191574

We have determined the binding strengths between nucleotides of adenine, thymine, guanine and cytosine in homogeneous single stranded DNAs and homo-octapeptides consisting of 20 common amino acids. We use a bead-based fluorescence assay for these measurements in which octapeptides are immobilized on the bead surface and ssDNAs are in solutions. Comparative analyses of the distribution of the binding energies reveal unique binding strength patterns assignable to each DNA nucleotide and amino acid originating from the chemical structures. Pronounced favorable (such as Arg-G, etc.) and unfavorable (such as Ile-T, etc.) binding interactions can be identified in selected groups of amino acid and nucleotide pairs that could provide basis to elucidate energetics of amino-acid-nucleotide interactions. Such interaction selectivity, specificity and polymorphism establish the contributions from DNA backbone, DNA bases, as well as main chain and side chain of the amino acids.


DNA, Single-Stranded , Nucleotides , Amino Acids/chemistry , Cytosine/chemistry , DNA/chemistry , Nucleotides/chemistry , Oligopeptides , Thymine/chemistry
16.
Dalton Trans ; 51(1): 241-249, 2021 Dec 20.
Article En | MEDLINE | ID: mdl-34881763

The facile fabrication of low-cost photocatalysts with enhanced activity and high atomic utilization is becoming increasingly necessary for solar energy usage and/or conversion. In this work, a series of mesoporous carbon nitride nanosheets with an enlarged specific surface area was synthesized via an inorganic acid-assisted exfoliation method without any soft or hard templates. An ultralow loading of downsized noble metal Pt was anchored on these porous nanosheets, exhibiting enhanced photocatalytic activity. The formation of mesoporous nanosheets in carbon nitride was expected to boost the mass transfer and shorten the charge carrier transfer route during the photocatalytic reaction. The characterization of samples revealed that the enhanced conductivity and photocurrent of the carbon nitride nanosheets also contributed to the enhanced H2 evolution activity. The maximum H2 production rates of 172.92 µmol h-1 and 321 µmol h-1 were achieved over the nanosheets derived from melamine and urea under visible light irradiation, which are 10.92- and 2.22-fold that of the corresponding bulk carbon nitride, respectively. This exfoliation method was demonstrated to be an efficient and universal method for the preparation of carbon nitride nanosheets with a mesoporous structure and high atom utilization of the co-catalyst for H2 evolution from water.

17.
ACS Chem Neurosci ; 12(22): 4257-4264, 2021 11 17.
Article En | MEDLINE | ID: mdl-34726371

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases characterized by progressive cognitive decline. Early diagnosis and dynamic monitoring are essential to the treatment and care of AD but challenging. Here we develop a noninvasive, blood-based AD detection method based on surface plasmonic resonance imaging (SPRi) technique. The functionalized sensing SPRi chips were constructed with self-assembled loop-displaying peptoid nanosheets to improve the detection sensitivity of plasma amyloid ß42 (Aß42). We analyze the plasma from 30 clinically diagnosed AD patients, 29 amnestic cognitive impairment (aMCI) patients, and 30 control individuals and demonstrate that this sensing system can significantly distinguish the three groups with high sensitivity and specificity. In the follow-up studies of the aMCI patients, we find that decrease in the binding signals in the patients correlates with the disease progression into AD whereas the almost unchanged signals correlate with stable disease remaining at aMCI status. These results show the capability of the peptoid-nanosheet-based SRPi sensing system for the early diagnosis and dynamic monitoring of AD.


Alzheimer Disease , Cognitive Dysfunction , Peptoids , Alzheimer Disease/diagnosis , Cognitive Dysfunction/diagnosis , Disease Progression , Humans , Neuropsychological Tests
18.
Adv Sci (Weinh) ; 8(18): e2100825, 2021 09.
Article En | MEDLINE | ID: mdl-34338437

The nanomechanical properties of tumor-derived small extracellular vesicles (sEVs) are essential to cancer progression. Here, nanoindentation is utilized on atomic force microscopy (AFM) to quantitatively investigate the nanomechanical properties of human breast cancer cell-derived sEVs at single vesicle level and explore their relationship with tumor malignancy and vesicle size. It is demonstrated that the stiffness of the sEVs results from the combined contribution of the bending modulus and osmotic pressure of the sEVs. The stiffness and osmotic pressure increase with increasing malignancy of the sEVs and decrease with increasing size of the sEVs. The bending modulus decreases with increasing malignancy of the sEVs and is lower in smaller sEVs. This study builds relationship between the nanomechanical signature of the sEV and tumor malignancy, adding information for better understanding cancer mechanobiology.


Breast Neoplasms/pathology , Extracellular Vesicles/pathology , Nanomedicine/methods , Cells, Cultured , Evaluation Studies as Topic , Female , Humans
19.
Plants (Basel) ; 10(2)2021 Feb 17.
Article En | MEDLINE | ID: mdl-33671307

There are very few studies about the effects of relatively higher CO2 concentration (e.g., 1000 µmol·mol-1) or plus N fertilization on woody plants. In this study, Schima superba seedings were exposed to ambient or eCO2 (550, 750, and 1000 µmol·mol-1) and N fertilization (0 and 10 g·m-2·yr-1, hereafter: low N, high N, respectively) for one growth season to explore the potential responses in a subtropical site with low soil N availability. N fertilization strongly increased leaf mass-based N by 118.38%, 116.68%, 106.78%, and 138.95%, respectively, in different CO2 treatments and decreased starch, with a half reduction in leaf C:N ratio. Leaf N was significantly decreased by eCO2 in both low N and high N treatments, and N fertilization stimulated the decrease of leaf N and mitigated the increase of leaf C:N by eCO2. In low N treatments, photosynthetic rate (Pn) was maximized at 733 µmol·mol-1 CO2 in August and September, while, in high N treatments, Pn was continuously increased with elevation of CO2. N fertilization significantly increased plant biomass especially at highly elevated CO2, although no response of biomass to eCO2 alone. These findings indicated that N fertilization would modify the response of S. superba to eCO2.

20.
Sci Total Environ ; 771: 144883, 2021 Jun 01.
Article En | MEDLINE | ID: mdl-33736155

Understanding pollen transport pathways and dispersal mechanism from the land to sea is a prerequisite for marine palynological study. Palynological analysis of 164 surface sediment samples in Liaodong Bay, and 39 analogous surface alluvium samples from its five inflowing rivers, identifies the distribution patterns, pathways and possible sources of pollen and spores. The results show that pollen and spore assemblages in surface sediments are well correlated to regional vegetation distribution, and the variations of pollen assemblage in different parts of Liaodong Bay reflected local vegetation changes along the coast. High pollen concentrations are mainly distributed in the estuaries of inflowing rivers, coastal waters and sea muddy areas. The pollen assemblage characteristics of alluvial samples are similar to those from coastal waters with water depths <8.5 m. Samples from the alluvium and surface sediments of coastal waters were dominated by herbaceous pollen taxa including Artemisia, Amaranthaceae, Poaceae, Cyperaceae and Typha. Herbaceous pollen percentages and concentrations decreased as the water depth increased, indicating that pollen and spores in the coastal waters of Liaodong Bay are mainly carried by the inflowing rivers. However, pollen assemblages for samples with water depth >8.5 m are significantly different from those of the alluvium. In samples taken below a depth of 8.5 m, the arboreal pollen is dominated by airborne Pinus, and there is a high number of the waterborne Selaginella fern spores, both of which are sourced from a wider region. In the Liaodong Bay, both wind and ocean current transportation determines the pollen distribution patterns in deeper waters, while fluvial and longshore current transportation determines the pollen assemblages found in shallow waters. The dispersal characteristics of pollen assemblages between the land and the sea in Liaodong Bay provide a theoretical basis for the interpretation of fossil pollen assemblages and past sea level changes.


Bays , Water Pollutants, Chemical , China , Environmental Monitoring , Estuaries , Geologic Sediments , Pollen/chemistry , Rivers , Water Pollutants, Chemical/analysis
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