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Spatial patterns and determinants of common root-associated fungi in a subtropical forest of China

Journal of Plant Ecology 2019年第2期12卷 255-263页

作者： Abdul Shakoor Shan Li Fang Wang Tian Tian yu Liang keping Ma State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences20 NanxincunXiangshanBeijing 100093China University of Chinese Academy of Sciences Beijing 100049China Department of Evolutionary Biology and Environmental Studies University of ZurichCH-8057 ZurichSwitzerland

Aims Spatial patterns of fungal populations are affected by plant distribu-tion,abiotic factors,fungal dispersal ability and inter-species *** several studies have addressed spatial patterns of some mycorrhizal,saprotrophic and pathogenic fungi,the method based on fruit-body surveys is not efficient and unreliable to study the spa-tial pattern of root-associated fungal species because most fungi in plant roots do not have sporocarps and cannot be identified based only on morphological *** aims are(i)to determine the spa-tial pattern of common root-associated fungi;(ii)to evaluate whether the abundance and spatial pattern of root-associated fungi and cat-egories of fungi,reflect their biotic and abiotic niche *** About 828 soil cores were collected from a 24-ha plot in a sub-tropical forest and Illumina Miseq was carried out to determine fungal composition in root samples and spatial patterns of 1009 common fungal Operational Taxonomic Units(OTUs)were studied using point pattern ***(plant community composition)and abiotic niche constraints on the presence/abundance of a fun-gal OTU was assessed as the n-dimensional niche hypervolumes of biotic and abiotic *** Findings Our results showed that(i)most fungal OTUs were highly spa-tially aggregated at small scales(less than 30 m),but that the aggregated pattern decreased,while regular and random patterns increased,with the increasing distance;(ii)A significant positive correlation was found between fungal abundance and aggrega-tion intensity of fungal OTUs,indicating that the dominant fungi tended to be more aggregated in natural forests;(iii)Mean abun-dance and spatial aggregation intensity of ectomycorrhizal and pathogenic fungi were relatively higher than those of saprotrophic fungi,indicating that host plants may play an important role in determining spatial pattern of root-associated fungi;(iv)Spatial patterns of root-associated fungi depended o

关键词： spatial pattern fungal population subtropical forests high-throughput sequencing dispersal niche hypervolume

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Effects of functional phylogeny of light-response-related orthologous genes on seedling survival in a subtropical forest

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Forest Ecosystems 2023年第1期10卷 31-36页

作者： Hui Shang yunquan Wang Baocai Han Xiangcheng Mi Lei Chen yu Liang keping Ma State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China University of Chinese Academy of Sciences Beijing 100049China Shanghai Chenshan Plant Science Research Center Chinese Academy of SciencesShanghai Chenshan Botanical GardenShanghai 201602China College of Chemistry and Life Sciences Zhejiang Normal UniversityJinhua 321004China State Key Laboratory of Systematic and Evolutionary Botany Institute of BotanyChinese Academy of SciencesBeijing 100093China

Background: Light is an important environmental factor affecting the growth and survival of plants in forest communities. The competition for light resources and divergent responses to light may affect plant species coexistence in natural forests through niche partitioning and environmental filtering, ***: In the present study, sequences of light-response-related functional genes were extracted from transcriptomic data of 99 tree species in a subtropical forest and average and nearest taxon phylogenetic diversity of adult(A_Apd’, A_NTpd’) and seedling neighbors(S_Apd’, S_NTpd’) around each focal seedling were calculated to evaluate effects of differentiation in light-response-related genes on community assembly ***: The results showed that seedling survival was related to S_NTpd’, S_Apd’and A_Apd’of two chlorophyll ab-binding proteins involved in the assembly of photosystem Ⅱ and two genes responsive to light intensity,indicating seedlings surrounded by neighbors with distinct light responses tended to have high survival ***: Our results indicated that niche partitioning due to competition for light resources between plants may act as the key mechanism in determining seedling dynamics in subtropical forests.

关键词： Species co-existence Forest communities Neighbor effects Community genomics Negative density dependence Niche partitioning

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Theoretical analysis of PAM-N and M-QAM BER computation with single-sideband signal

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Science China(Information Sciences) 2021年第8期64卷 172-181页

作者： Dongxu LU Xian ZHOU yuqiang YANG Jiahao HUO Jinhui yuAN keping LONG Changyuan yu Alan Pak Tao LAU Chao LU Beijing Engineering and Technology Research Center for Convergence Networks and Ubiquitous Services University of Science and Technology Beijing Department of Electrical Engineering The Hong Kong Polytechnic University Department of Electronic and Information Engineering The Hong Kong Polytechnic University

In this paper, the theoretical bit error rate(BER) of N-level pulse amplitude modulation(PAMN)and M-ary quadrature amplitude modulation(M-QAM) have been studied and compared under different scenarios, including(i) PAM with intensity modulation with direct detection(IM/DD) and field modulation with detection(FMD)(including coherent detection and single-sideband modulation with direct detection(SSB-DD)), and(ii) QAM with coherent detection and SSB-DD. Considering the relationship between the symbol spacing and signal-to-noise ratio(SNR), we provide the mathematical BER equations, including the optical signal-to-noise ratio(OSNR) and carrier-to-signal power ratio(CSPR), especially for PAM *** verify the validity of our theoretical expressions for SSB systems, transmissions with 224-Gb/s SSBPAM4/16 QAM signals using the Kramers-Kronig(KK) receiver were implemented on a unified optical system platform. The simulation results agreed well with theoretical calculations both in back-to-back(BtB) and120-km transmission scenarios, which showed that the BER evaluation methods can serve as a theoretical guidance and system assessment criteria for SSB scenarios.

关键词： N-level pulse amplitude modulation(PAM-N) M-ary quadrature amplitude modulation(MQAM) BER computation single-sideband(SSB) Kramers-Kronig receiver

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Examining residual spatial correlation in variation partitioning of beta diversity in a subtropical forest

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Journal of Plant Ecology 2019年第4期12卷 636-644页

作者： Ke Cao Xiangcheng Mi Liwen Zhang Haibao Ren Mingjian yu Jianhua Chen Jintun Zhang keping Ma Key Laboratory of Biodiversity Sciences and Ecological Engineering Ministry of EducationCollege of Life SciencesBeijing Normal UniversityBeijing 100875China State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of Sciences20 NanxingcunXiangshanBeijing 100093China Key Laboratory of Coastal Zone Environmental Processes Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China College of Life Sciences Zhejiang UniversityHangzhou 310058China College of Chemistry and Life Sciences Zhejiang Normal UniversityJinhua 321004China

Aims The relative roles of ecological processes in structuring beta diver-sity are usually quantified by variation partitioning of beta diversity with respect to environmental and spatial variables or gamma ***,if important environmental or spatial factors are omitted,or a scale mismatch occurs in the analysis,unaccounted spatial correlation will appear in the residual errors and lead to re-sidual spatial correlation and problematic *** Multi-scale ordination(MSO)partitions the canonical ordination results by distance into a set of empirical variograms which charac-terize the spatial structures of explanatory,conditional and residual variance against *** these variance components can be used to diagnose residual spatial correlation by checking assump-tions related to geostatistics or regression *** this paper,we first illustrate the performance of MSO using a simulated data set with known properties,thus making statistical issues *** then test for significant residual spatial correlation in beta diversity analyses of the Gutianshan(GTS)24-ha subtropical forest plot in eastern *** Findings Even though we used up to 24 topographic and edaphic variables mapped at high resolution and spatial variables representing spa-tial structures at all scales,we still found significant residual spatial correlation at the 10 m×10 m quadrat *** invalidated the analysis and inferences at this *** also show that MSO pro-vides a complementary tool to test for significant residual spatial correlation in beta diversity *** results provided a strong argument supporting the need to test for significant residual spatial correlation before interpreting the results of beta diversity analyses.

关键词： beta analysis residual spatial correlation spatial scale canonical ordination multi-scale ordination variation partitioning

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Theoretical and numerical analyses for PDM-IM signals using Stokes vector receivers

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Science China(Information Sciences) 2020年第10期63卷 194-202页

作者： Jiahao HUO Xian ZHOU Chao SHANG Wei HUANGFU Jinhui yuAN Huansheng NING keping LONG Changyuan yu Alan Pak Tao LAU Chao LU Beijing Engineering and Technology Research Center for Convergence Networks and Ubiquitous Services University of Science and Technology Beijing Department of Electronic and Information Engineering The Hong Kong Polytechnic University Key Laboratory of Luminescence and Optical Information Ministry of EducationInstitute of Optical InformationSchool of ScienceBeijing Jiaotong University Department of Electrical Engineering The Hong Kong Polytechnic University

Different from current coherent-detection-based long-haul transmission systems, inter-and intradatacenter transmissions require a simpler transmitter and receiver. A promising way to significantly meet the demands of datacenter transmission is polarization division multiplexing intensity modulation with direct detection(PDM-IM-DD) using a Stokes vector receiver(SVR). However, for different SVR architectures,the corresponding demultiplexing matrix is required to recover the Stokes vectors from the detected signals,which are combined with an arbitrary state of polarization(SOP), will change the effect of noise dynamically and significantly influence the system performance. In this study, PDM-IM signals using four SVRs,i.e., a 90? optical hybrid with 2 balanced photodetectors(BPDs) and 2 photodetectors(PDs), a 90? optical hybrid with 4 PDs, a Stokes analyzer and a 3×3 coupler with 4 PDs, are studied theoretically and numerically. Theoretical system models using the four SVRs are developed, and the noise power variations are analyzed quantitatively based on these models. Moreover, the performance of the systems is also investigated for 224 Gbit/s polarization division multiplexing pulse amplitude modulation 4 level with direct detection(PDM-PAM4-DD) transmission in a simulation. The simulation results show that the bit error rate(BER)performance of the systems is consistent with the theoretical noise power variation curves. The theoretical analysis scheme is helpful for the practical design of SVR-based systems.

关键词： short-reach optical communications PAM4 polarization division multiplexing Stokes vector direct detection

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Multi-stemming strategies of Quercus glauca in an evergreen broad-leaved forest: when and where

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Journal of Plant Ecology 2020年第6期13卷 738-743页

作者： Mide Rao Duo Ye Jianhua Chen Jian Ni Xiangcheng Mi Mingjian yu keping Ma Johannes H.C.Cornelissen College of Chemistry and Life Sciences Zhejiang Normal UniversityJinhua 321004China Department of Ecological Science Faculty of ScienceVrije Universiteit AmsterdamDe Boelelaan 10851081 HV AmsterdamThe Netherlands State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China College of Life Sciences Zhejiang UniversityHangzhou 310058China

Aims Multi-stemming supports plants’resilience to disturbances and then contributes to soil stabilization and forest function,especially in mountain *** questions remain about(i)the ontogenetic phase at which multiple stems can occur,(ii)how habitat drivers affect multi-stemming and(iii)whether ontogenetic phase and habitat drivers *** asked these questions for Quercus glauca(ring-cupped oak),the dominant species and sprouter across large warm-temperate areas of Asia;its multi-stemmed trees reflect individual survival,population regeneration and forest ecosystem *** In a 5-ha permanent plot of subtropical evergreen broad-leaved forest in eastern China,we examined the temporal patterns and spatial distribution of multi-stemmed trees of *** within 99 quadrats of 20 m×20 *** Findings There were three temporal modes for multi-stemming among the *** trees and most of them appeared to produce multiple stems from an early *** disturbances related to slope convexity appear to be the main drivers of multi-stemming of ***,the closer to the ridge,the earlier the multi-stemming ***,also for other woody species in other forests and climate zones,ontogeny and environmental drivers promoting disturbance(not only geomorphology,but also extreme weather events,soil drought,fire),as well as soil fertility,need to be considered in combination to better understand multi-stemming and its consequences for community structure.

关键词： life history strategy multi-stemmed trees ontogenetic phase persistence Quercus glauca topography

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Down-regulation of microRNA-23a promotes pancreatic ductal adenocarcinoma initiation and progression by up-regulation of FOXM1 expression

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Genes & Diseases 2024年第5期11卷 456-469页

作者： Lixin Liang Tian Cai Xiaojia Li Jianhong An Sen yu Yang Zhang Fengjie Guo Fang Wei Jie He keping Xie Tingting Jiang Center for Pancreatic Cancer Research South China University of Technology School of MedicineGuangzhouGuangdong 510006China Department of Laboratory Medicine The Sixth Affiliated Hospital and Nanhai People’s HospitalSouth China University of Technology School of MedicineFoshanGuangdong 528200China The Second Affiliated Hospital and Guangzhou First People’s Hospital South China University of Technology School of MedicineGuangzhouGuangdong 510006China

Transcriptional factor Forkhead box M1(FOXM1)plays an important role in pancreatic ductal adenocarcinoma(PDAC)development and *** molecular mechanisms underlying its dysregulation remain *** identified and functionally validated the microRNAs(miRNAs)that critically regulate FOXM1 expression in *** expression levels of miRNA-23a(miR-23a-3p and-5p)were altered in PDAC cell lines and their effects on FOXM1 signaling and cell proliferation and migration and tumorigenesis were examined in vitro and in vivo using mouse PDAC *** with non-tumor pancreatic tissues,PDAC tissues and cell lines exhibited significantly reduced levels of miR-23a *** miR-23a expression and concomitant increase in FOXM1 expression were also observed in acinar-toductal metaplasia and pancreatic intraepithelial neoplasia,the major premalignant lesions of *** expression of miR-23a reduced the expression of FOXM1 and suppressed cell proliferation and migration in PDAC cells,whereas the inhibitors of miR-23a did the *** or reduced levels of miR-23a increased the levels of FOXM1 expression,while increased expression of FOXM1 down-regulated miR-23a expression,suggesting that miR-23a and FOXM1 were mutual negative regulators of their expression in PDAC ***,the miR-23a/FOXM1 signaling axis is important in PDAC initiation and progression and could serve as an interventional or therapeutic target for patients with early or late stages of PDAC.

关键词： FOXM1 Gene expression Gene regulation MicroRNA Pancreatic cancer Targeted therapy

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Design of diamond-shape photonic crystal fiber polarization filter based on surface plasma resonance effect

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Chinese Physics B 2020年第3期29卷 232-237页

作者： Yongxia Zhang Jinhui yuan yuwei Qu Xian Zhou Binbin Yan Qiang Wu Kuiru Wang Xinzhu Sang keping Long Chongxiu yu Research Center for Convergence Networks and Ubiquitous Services University of Science and Technology Beijing(USTB)Beijing 100083China State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China Department of Physics and Electrical Engineering Northumbria UniversityNewcastle upon TyneNE18STUnited Kingdom

A novel plasmonic polarization filter based on the diamond-shape photonic crystal fiber(PCF) is proposed. The resonant coupling characteristics of the PCF polarization filter are investigated by the full-vector finite-element method. By optimizing the geometric parameters of the PCF, when the fiber length is 5 mm, the polarization filter has a bandwidth of 990 nm and an extinction ratio(ER) of lower than -20 dB. Moreover, a single wavelength polarization filter can also be achieved, along with an ER of -279.78 dB at wavelength 1.55 μm. It is believed that the proposed PCF polarization filter will be very useful in laser and optical communication systems.

关键词： photonic crystal fiber polarization filter extinction ratio

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Differential impacts of adult trees on offspring and non-offspring recruits in a subtropical forest

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Science China(Life Sciences) 2022年第10期65卷 1905-1913页

作者： Fang Wang Xiangcheng Mi Lei Chen Wubing Xu Walter Durka Nathan GSwenson Daniel JJohnson Samantha JWorthy Jianhua Xue Yan Zhu Bernhard Schmid yu Liang keping Ma State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China University of Chinese Academy of Sciences Beijing 100049China German Centre for Integrative Biodiversity Research(iDiv)Halle-Jena-Leipzig Puschstrasse 404103 LeipzigGermany Department Community Ecology Centre for Environmental Research–UFZTheodor-Lieser-Str.4Halle 06120Germany Department of Biological Sciences University of Notre DameNotre DameIndiana 46556USA University of Notre Dame Environmental Research Center Land O’LakesWisconsin 54540USA School of Forest Fisheriesand Geomatics SciencesUniversity of FloridaGainesvilleFlorida32611USA Department of Biology University of MarylandCollege ParkMaryland 20742USA Department of Geography Remote Sensing LaboratoriesUniversity of ZürichZürich CH-8006Switzerland Institute of Ecology College of Urban and Environmental SciencesPeking UniversityBeijing 100085China

An important mechanism promoting species coexistence is conspecific negative density dependence(CNDD),which inhibits conspecific neighbors by accumulating host-specific enemies near adult *** enemies may be genotype-specific and regulate offspring dynamics more strongly than non-offspring,which is often neglected due to the difficulty in ascertaining genetic ***,we investigated whether offspring and non-offspring of a dominant species,Castanopsis eyrei,suffered from different strength of CNDD based on parentage assignment in a subtropical *** found decreased recruitment efficiency(proxy of survival probability)of offspring compared with non-offspring near adult trees during the seedling-sapling transition,suggesting genotype-dependent interactions drive tree demographic ***,the genetic similarity between individuals of same cohort decreased in late life history stages,indicating genetic-relatedness-dependent tree mortality throughout *** results demonstrate that within-species genetic relatedness significantly affects the strength of CNDD,implying genotype-specific natural enemies may contribute to population dynamics in natural forests.

关键词： genetic relatedness conspecific negative density dependence Janzen-Connell hypothesis species coexistence forest dynamics plot subtropical forest

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Interspecific and intraspecific variation in specific root length drives aboveground biodiversity effects in young experimental forest stands

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Journal of Plant Ecology 2017年第1期10卷 158-169页

作者： Wensheng Bu Bernhard Schmid Xiaojuan Liu Ying Li Werner Härdtle Goddert von Oheimb yu Liang Zhenkai Sun yuanyuan Huang Helge Bruelheide keping Ma State Key Laboratory of Vegetation and Environmental Change Institute of BotanyChinese Academy of SciencesBeijing 100093China College of Forestry Jiangxi Agricultural UniversityNanchang 330045China Department of Evolutionary Biology and Environmental Studies University of ZürichWinterthurerstr.190Zürich 8057Switzerland Institute of Ecology Leuphana University LüneburgScharnhorststr.1Lüneburg 21335Germany Institute of General Ecology and Environmental Protection Technische Universität DresdenPienner Str.7Tharandt 01737Germany Institute of Biology/Geobotany and Botanical Garden Martin Luther University Halle-WittenbergAm Kirchtor 1Halle 06120Germany German Centre for Integrative Biodiversity Research(iDiv)Halle-Jena-Leipzig DeutscherPlatz 5eLeipzig 04103Germany

Aims Although the net biodiversity effect(NE)can be statistically partitioned into complementarity and selection effects(CE and SE),there are different underlying mechanisms that can cause a certain *** objective was to assess the role of resource partitioning and species interactions as two important mechanisms that can bring about CEs by interspecific and intraspecific trait *** We measured tree height of 2493 living individuals in 57 plots and specific root length(SRL)on first-order roots of 368 of these individuals across different species richness levels(1,2,4,8 species)in a large-scale forest biodiversity and ecosystem functioning experiment in subtropical China(BEF-China)established in *** describe the effects of resource partitioning between species by a fixed component of interspecific functional diversity(RaoQ)and further effects of species interactions by variable components of interspecific and intraspecific functional diversity(community weighted trait similarity and trait dissimilarity,CWS and CWD).Finally,we examined the relationships between biodiversity effects on stand-level tree height and functional diversity(RaoQ,CWS and CWD)in SRL using linear regression and assessed the relative importance of these three components of functional diversity in explaining the diversity *** Findings Our results show that species richness significantly affected SRL in five and tree height in ten out of 16 species.A positive NE was generally brought about by a positive CE on stand-level tree height and related to high values of RaoQ and CWS in SRL.A positive CE was related to high values of all three components of root functional diversity(RaoQ,CWS and CWD).Our study suggests that both resource partitioning and species interactions are the underlying mechanisms of biodiversity effects on stand-level tree growth in subtropical forest.

关键词： aboveground complementarity effects belowground resource partitioning biodiversity and ecosystem functioning species interactions tree height

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