期刊文献+
共找到282篇文章
< 1 2 15 >
每页显示 20 50 100
Intraspecific floral colour variation in three Pedicularis species
1
作者 Qiu-Yu Zhang Zhe Chen +1 位作者 Hang Sun Yang Niu 《Plant Diversity》 SCIE CAS CSCD 2024年第2期274-279,共6页
Flower constancy describes the phenomenon that pollinators tend to successively visit flowers of a single species during foraging,reducing reproductive interference in natural communities.The extent of flower constanc... Flower constancy describes the phenomenon that pollinators tend to successively visit flowers of a single species during foraging,reducing reproductive interference in natural communities.The extent of flower constancy is largely determined by the floral traits of co-flowering species.Both higher inter-specific and lower intraspecific differences of floral traits should contribute to a higher level of flower constancy.However,previous studies mainly focused on interspecific difference,and the intraspecific variation(consistency)of floral traits received much less attention.We hypothesise that selection may favour lower intraspecific floral trait variation in communities composed of multiple co-flowering congeners.We investigated the floral colour variation of three focal Pedicularis species that share pollinators in 19communities composed of either single or multiple Pedicularis species.Colour was quantified using image-based colour analysis as perceived by pollinators.We found that most of the intrapopulation floral colour variation was below the colour discrimination threshold of bumblebees,implying strongly constrained by the visual selection by pollinators.Contrary to the hypothesis,there is no significant difference in intraspecific floral colour variation between different community contexts.It may be due to the relatively large interspecific floral colour differences of most co-flowering species.The influence of community context on intraspecific variation may be reflected in floral traits other than colours. 展开更多
关键词 Flower constancy Floral colour variation Plantepollinator interactions Pollinator vision
下载PDF
Time dependence of entropy flux and entropy production for a dynamical system driven by noises with coloured cross-correlation 被引量:2
2
作者 谢文贤 徐伟 蔡力 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第1期42-46,共5页
This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the def... This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the definition of Shannon's information entropy, the time dependence of entropy flux and entropy production can be calculated. The present results can be used to explain the extremal behaviour of time dependence of entropy flux and entropy production in view of the dissipative parameter γ of the system, coloured cross-correlation time τ and coloured cross-correlation strength λ. 展开更多
关键词 information entropy entropy flux entropy production coloured cross-correlation Fokker-Planck equation
下载PDF
Upper bound for the time derivative of entropy for a dynamical system driven by coloured cross-correlated white noises 被引量:2
3
作者 谢文贤 徐伟 +1 位作者 蔡力 靳艳飞 《Chinese Physics B》 SCIE EI CAS CSCD 2005年第9期1766-1769,共4页
It is shown how the cross-correlation time and strength of coloured cross-correlated white noises can set an upper bound for the time derivative of entropy in a nonequilibrium system. The value of upper bound can be c... It is shown how the cross-correlation time and strength of coloured cross-correlated white noises can set an upper bound for the time derivative of entropy in a nonequilibrium system. The value of upper bound can be calculated directly based on the Schwartz inequality principle and the Fokker-Planck equation of the dynamical system driven by coloured cross-correlated white noises. The present calculations can be used to interpret the interplay of the dissipative constant and cross-correlation time and strength of coloured cross-correlated white noises on the upper bound. 展开更多
关键词 information entropy coloured cross-correlation Fokker-Planck equation
下载PDF
Thermoluminescence studies on γ-irradiated CaF_2:Dy:Pb:Na single crystals 被引量:2
4
作者 S.Masilla Moses Kennedy 《Journal of Rare Earths》 SCIE EI CAS CSCD 2009年第2期187-191,共5页
Therrnoluminescence (TL) glow, thermoluminescence emission (TLE) and thermal decay (TD) of optical absorption (OA) bands were studied on γ-irradiated CaF2:Dy (0.010at.%):Pb (0.188at.%):Na (0.026at.%)... Therrnoluminescence (TL) glow, thermoluminescence emission (TLE) and thermal decay (TD) of optical absorption (OA) bands were studied on γ-irradiated CaF2:Dy (0.010at.%):Pb (0.188at.%):Na (0.026at.%) single crystals (hereafter called crystal-I). The TL glow exhibited four glow peaks in the temperature region 300-500 K. The TL response with dose was studied up to -7.5 kGy. The total glow showed linear, supra linear and exponential growth with dose. The TLE showed bands characteristic of Dy^3+ ions (around 1.65, 1.87, 2.18 and 2.63 eV) and sodium associated (SA) colour centres (CCs) such as MNa (around 1.67 eV) and XNa (a new SA CC, with an emission band around 2.63 eV). The OA bands of MNa CC around 3.23 and 2.07 eV were found to decrease with temperature almost in accordance with the TL glow. The R+A centre absorption around 2.48 eV was found to grow with temperature initially and then decayed. The formation/growth of the CCs R+A and XNa might be from the conversion of the irradiation produced CC MNa. An attempt was made to explain the TL mechanism in the present system. 展开更多
关键词 CaF2:Dy:Pb:Na THERMOLUmineSCENCE thermoluminescence emission colour centres rare earths
下载PDF
Stochastic resonance driven by time-modulated correlated coloured noise sources in a single-mode laser 被引量:1
5
作者 陈德彝 张莉 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第5期1755-1760,共6页
This paper investigates the phenomenon of stochastic resonance in a single-mode laser driven by time-modulated correlated coloured noise sources. The power spectrum and signal-to-noise ratio R of the laser intensity a... This paper investigates the phenomenon of stochastic resonance in a single-mode laser driven by time-modulated correlated coloured noise sources. The power spectrum and signal-to-noise ratio R of the laser intensity are calculated by the linear approximation. The effects caused by noise self-correlation time τ1, τ2 and cross-correlated time τ3 for stochastic resonance are analysed in two ways: τ1, τ2 and τ3 are taken to be the independent variables and the parameters respectively. The effects of the gain coefficient F and loss coefficient K on the stochastic resonance are also discussed. It is found that besides the presence of the standard form and the broad sense of stochastic resonance, the number of extrema in the curve of R versus K is reduced with the increase of the gain coefficient Г. 展开更多
关键词 coloured noise coloured correlation time-periodic modulation signal-to-noise ratio
下载PDF
Stochastic resonance in a single-mode laser driven by frequency modulated signal and coloured noises 被引量:1
6
作者 金国祥 张良英 曹力 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第3期952-957,共6页
By adding frequency modulated signals to the intensity equation of gain noise model of the single-mode laser driven by two coloured noises which are correlated, this paper uses the linear approximation method to calcu... By adding frequency modulated signals to the intensity equation of gain noise model of the single-mode laser driven by two coloured noises which are correlated, this paper uses the linear approximation method to calculate the power spectrum and signal-to-noise ratio (SNR) of the laser intensity. The results show that the SNR appears typical stochastic resonance with the variation of intensity of the pump noise and quantum noise. As the amplitude of a modulated signal has effects on the SNR, it shows suppression, monotone increasing, stochastic resonance, and multiple stochastic resonance with the variation of the frequency of a carrier signal and modulated signal. 展开更多
关键词 Gaussian coloured noise single-mode laser stochastic resonance frequency modulated signal
下载PDF
Stochastic resonance in an asymmetric bistable system driven by coloured noises 被引量:1
7
作者 杨建华 刘先斌 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第5期92-97,共6页
The phenomenon of stochastic resonance is investigated in an asymmetric bistable system with coloured noises. The approximate Fokker Planck equation is derived based on the Novikov theorem and the Fox approach. By app... The phenomenon of stochastic resonance is investigated in an asymmetric bistable system with coloured noises. The approximate Fokker Planck equation is derived based on the Novikov theorem and the Fox approach. By applying the two-state theory, the expression of the signal-to-noise ratio is obtained in the adiabatic limit. The effects of the noise parameters on signal-to-ratio are discussed. It is found that the stochastic resonance phenomena appear in most cases and disappear in some special cases. 展开更多
关键词 stochastic resonance asymmetric bistable system coloured noises
下载PDF
Formation and instability of spiral wave induced by Gaussian coloured noise 被引量:1
8
作者 甘正宁 马军 +1 位作者 张国勇 陈勇 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第11期4047-4055,共9页
In this paper, we studied the effect of Gaussian coloured noise on the formation and instability of spiral waves described by one class of modified FitzHugh Nagumo equation. It was found that Gaussian coloured noise p... In this paper, we studied the effect of Gaussian coloured noise on the formation and instability of spiral waves described by one class of modified FitzHugh Nagumo equation. It was found that Gaussian coloured noise plays a constructive role in the formation, transition and instability of spiral wave. Too weak or too strong noise may act against the formation of spiral waves. At a certain noise level, spiral wave is maintained in a medium, in which spiral wave cannot be observed in the absence of the noise. It is difficult to make a stable spiral wave into unstable state by Gaussian coloured noise, unless the noise level is very high. The parameter regions of Gaussian coloured noise for spiral forming and spiral instability were given and discussed with numerical simulations. 展开更多
关键词 spiral wave FitzHugh-Nagumo model Gaussian coloured noise
下载PDF
Modeling and Analyzing Web Application with Aspect-Oriented Hierarchical Coloured Petri Nets 被引量:1
9
作者 Xiaoxing Sun Huiqun Yu +1 位作者 Honghao Liang Nianhua Yang 《China Communications》 SCIE CSCD 2016年第5期89-102,共14页
Aspect-oriented modeling can uncover potential design faults, yet most existing work fails to achieve both separation and composition in a natural and succinct way. This study presents an aspect-oriented modeling and ... Aspect-oriented modeling can uncover potential design faults, yet most existing work fails to achieve both separation and composition in a natural and succinct way. This study presents an aspect-oriented modeling and analysis approach with hierarchical Coloured Petri Nets(HCPN). HCPN has sub-models and well-defined semantics combining a set of submodels. These two characteristics of HCPN are nicely integrated into aspect oriented modeling. Submodels are used to model aspects while the combination mechanism contributes to aspects weaving. Furthermore, the woven aspect oriented HCPN model can be simulated and analyzed by the CPN Tools. A systematic web application case study is conducted. The results show the system original properties are satisfied after weaving aspects and all design flaws are revealed. As such, the approach can support web application design and analysis in an aspect-oriented fashion concisely and effectively. 展开更多
关键词 aspect-oriented modeling hierarchical coloured Petri net CPN Tools ASKCTL
下载PDF
Provenance of Coloured Gemstones-Availability,Testing Methods,Future Trends 被引量:1
10
作者 Lore Kiefert Klemens Link 《宝石和宝石学杂志》 CAS 2018年第S1期145-146,共2页
Gemstones have fascinated mankind forever,and people traveled far to find them.The Silk Road is one of the most traditional trade routes in the middle ages that was used to bring the precious stones to the European ma... Gemstones have fascinated mankind forever,and people traveled far to find them.The Silk Road is one of the most traditional trade routes in the middle ages that was used to bring the precious stones to the European market.Later,emeralds from Colombia were shipped via the ocean to the Old World. 展开更多
关键词 Provenance of coloured Gemstones-Availability Testing Methods Future Trends
下载PDF
Effects of signal modulation and coloured cross-correlation of coloured noises on the diffusion of a harmonic oscillator
11
作者 刘立 张良英 曹力 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第10期4182-4186,共5页
The diffusion in a harmonic oscillator driven by coloured noises ξ(t) and η(t) with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expre... The diffusion in a harmonic oscillator driven by coloured noises ξ(t) and η(t) with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expression of diffusion coefficient d as a function of noise parameter, signal parameter, and oscillator frequency is derived. The findings in this paper are as follows. 1) The curves of d versus noise intensity D and d versus noises cross-correlation time z3 exist as two different phases. The transition between the two phases arises from the change of the cross-correlation coefficient A of the two Ornstein-Uhlenbeck (O-U) noises. 2) Changing the value of T3, the curves of d versus Q, the intensity of colored noise that is modulated by the signal, can transform from a phase having a minimum to a monotonic phase. 3) Changing the value of signal amplitude A, d versus Q curves can transform from a phase having a minimum to a monotonic phase. The above-mentioned results demonstrate that a like noise-induced transition appears in the model. 展开更多
关键词 coloured cross-correlation cross-correlation coefficient diffusion coefficient signal modulated noise noise-induced transition
下载PDF
Research on the Properties of the Naturally Coloured Cottons
12
作者 黄故 《Journal of Donghua University(English Edition)》 EI CAS 2004年第6期63-65,共3页
Structures and characteristics of naturally coloured cottons grown in China were analyzed. Breaking strength of yarns made of pure coloured cotton and coloured cotton fibres blended with other fibres were investigated... Structures and characteristics of naturally coloured cottons grown in China were analyzed. Breaking strength of yarns made of pure coloured cotton and coloured cotton fibres blended with other fibres were investigated. Colour fastness of the coloured cotton goods was tested. Suggestions for using the coloured cotton practically and effectively were also included. 展开更多
关键词 naturally coloured cotton ENVIRONMENTAL protection COTTON properties FIBRE structure
下载PDF
Transitions in a genotype selection model driven by coloured noises
13
作者 王参军 梅冬成 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第2期479-485,共7页
This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By d... This paper investigates a genotype selection model subjected to both a multiplicative coloured noise and an additive coloured noise with different correlation time τ1 and τ2 by means of the numerical technique. By directly simulating the Langevin Equation, the following results are obtained. (1) The multiplicative coloured noise dominates, however, the effect of the additive coloured noise is not neglected in the practical gene selection process. The selection rate μ decides that the selection is propitious to gene A haploid or gene B haploid. (2) The additive coloured noise intensity and the correlation time τ2 play opposite roles. It is noted that α and τ2 can not separate the single peak, while can make the peak disappear and ^-2 can make the peak be sharp. (3) The multiplicative coloured noise intensity D and the correlation time τ1 can induce phase transition, at the same time they play opposite roles and the reentrance phenomenon appears. In this case, it is easy to select one type haploid from the group with increasing D and decreasing τ1. 展开更多
关键词 genotype selection model coloured noise stationary probability distribution
下载PDF
AN EQUIVALENCE METHOD FOR COLOURED PETRI NETS AND PLACE/TRANSITION NETS
14
作者 罗军舟 《Journal of Southeast University(English Edition)》 EI CAS 1994年第2期98-104,共7页
Coloured Petri net(CPN)is a high-level net while place/transition net(PTN)is a low-level net.It is very important to establish the relationship betweenthe two nets both in theoretical analysis and practical applicatio... Coloured Petri net(CPN)is a high-level net while place/transition net(PTN)is a low-level net.It is very important to establish the relationship betweenthe two nets both in theoretical analysis and practical application.In this paper,wegive a formal method of translating a CPN into a behaviourally equivalent PTN.APTN and its behaviour are formally constructed,a PTN equivalence definition is giv-en,and the same properties of the two nets are proved. 展开更多
关键词 PETRI NETS coloured PETRI NETS place/transition NETS
下载PDF
ECOLOGICAL OBSERVATIONS ON COLOURED LAYER OF COASTAL FAST ICE IN GREAT WALL BAY, KING GEORGE ISLAND, ANTARCTICA
15
作者 Lu Peiding, Zhang Kuncheng, Huang Fengpeng and Kentaro WatanabeFirst Institute of Oceanography, S.O. A., Qingdao 266003 National Institute of Polar Research, Japan 《Chinese Journal of Polar Science》 1991年第1期39-45,共7页
Marine biological and environmental investigations were carried out on the coastatl waters off Great Wall Station (62°13's, 58°58'W) on King George Island, Antarctica, from November 17, 1988, to Marc... Marine biological and environmental investigations were carried out on the coastatl waters off Great Wall Station (62°13's, 58°58'W) on King George Island, Antarctica, from November 17, 1988, to March 3,1989. Coastal fast ice covered inner part of Great Wall Bay until mid-December 1988, which allowed us to take ice core sampling and observations from mid-November to early December 1988. During this period, ice thickness ranged from 90 to 70cm with baout 20cm of snow cover. About 5cm brown layer occured in the middle part of fast ice core collected on November 20, 1988 at site 2, and two brown layers occured in the interior of ice core collected on November 17,20 and 26, 1988 at site 5.In comparison to the water column, chlorophyll-a concentration in fast ice was higher, which ranged from 2.55 to 56.84mg/m8, and most of them were concentracted in the interior layers of sea ice rather than in the bottom layer often observed in other sea ice areas, such as in Syowa, Davis, Casey Station and McMurdo Sound areas, etc. This might be a result of the difference in structure and formation procese of sea ice.Meanwhile, temperature, transparency, nutrients and chlorophyll-a in water column were measured. Microalgal assemblages both in fast ice and water column of Great Wall Bay were reported. 展开更多
关键词 fast ice coloured layer ice algae.
下载PDF
Characterization and Application of Naturally Occurring Mineral Based Pigment in Surface Coating
16
作者 Shweta Umale Prakash Mahanwar 《Journal of Minerals and Materials Characterization and Engineering》 2012年第11期1101-1107,共7页
New naturally occurring mineral based pigment of general formula Hg2S have been processed and characterized for its application in surface coating. Various analytical protocol like XRD, FT-IR, SEM and CIE 1976 colour ... New naturally occurring mineral based pigment of general formula Hg2S have been processed and characterized for its application in surface coating. Various analytical protocol like XRD, FT-IR, SEM and CIE 1976 colour coordinate system have been performed for complete analysis of pigment. Characterizations using XRD, and CIE 1976 colour coordinate assessment reveal the formation of pigments displaying colours ranging from brick-red to dark-brown. The typical designed pigment samples have been evaluated for their mass tone/hiding power, tinting strength and weather resistance by coating on an MS steel panel. Optical, Chemical, Mechanical and performance properties of coating have been evaluated for its application. The results demonstrated that the dark-brown pigment obtained in the present study was found to be an interesting alternative to the existing classical toxic inorganic red pigments for surface coating applications. 展开更多
关键词 Light FASTNESS COLOUR VALUE Surface COATING Dispersability Refractive Index
下载PDF
Coloured materials in surface water in the sub Arctic Zone: An overview of its formation, properties and environmental changes
17
作者 Egil T. Gjessing 《Natural Science》 2013年第3期400-410,共11页
Natural organic matter (NOM) is present in most all surface water. This material is governing all chemical and all biological processes in the aquatic environment, and play a practical role in the drinking water indus... Natural organic matter (NOM) is present in most all surface water. This material is governing all chemical and all biological processes in the aquatic environment, and play a practical role in the drinking water industry From an increasing number of international reports, it is clear that the amount of this coloured matter is increasing in areas of the northern hemisphere. We is asked why and we suggest a combination of the following four reasons: 1) Climate (temperature, humidity, nature and frequency of precipitation);2) Quality and quantity of precipitation;3) Nature of catchment (topography and geology), and due to changes in local climate and 4) Quality and intensity of global radiation. In the early 1960s, there were reports from Scandinavia about the decline of coloured matter in lakes. The present increase in colour in our lakes and rivers is partly due to the fact that there are less mineral acids in precipitation. However, change in climate, most probably, plays an even more important role in many regions. As a consequence of the temperature increase, there will also be a change in the amount of precipitation and change in its regional and local distribution. As NOM is “produced” in soil and as the development is based on chemical and microbiological decomposition of plant residues, an increased temperature and more rain will extend the “production-area”. The “global dimming will also have a significant impact on an increased colour in surface water, as less photo-degradation and less bio-available organic matter is resulting. The positive correlation between the colour increase in surface water and the amount of precipitation, may indicate, that there might be a limited amount of water-extractable coloured material in the catchment. It is argued that that the “production” of the coloured matter will increase and that natural losses, such as “bleaching” etc. will be reduced down flow. Most probably a number of different environmental “elements” “mechanisms” are acting simultaneously and/or separately and differently. 展开更多
关键词 WATER Colour NOM HUMUS DRINKING WATER
下载PDF
BDS/GPS deformation analysis of a long-span cable-stayed bridge based on colored noise filtering 被引量:1
18
作者 Jun Ma 《Geodesy and Geodynamics》 CSCD 2023年第2期163-171,共9页
Combining GPS and BDS technology to monitor the deformation of long-span railway bridges with stricter deformation control requirements is of significance to the safety and control of the bridge and the safety of rail... Combining GPS and BDS technology to monitor the deformation of long-span railway bridges with stricter deformation control requirements is of significance to the safety and control of the bridge and the safety of railway traffic.Previous studies have ignored the influence of coloured noise in the deformation time series.This is not conducive to accurate deformation analysis of long-span railway bridges.Therefore,GPS,BDS and GPS/BDS monitoring data of Ganjiang Bridge located in Ganzhou city,Jiangxi Province,China are adopted in this paper to filter the coloured noise in the deformation time series by principal component analysis(PCA),and the influence of coloured noise on the deformation analysis results of railway bridge is analysed.The experimental results show that the diurnal temperature difference causes the mid-span and the tower of the railway cable-stayed bridge to deform with a period of about one day in the vertical and longitudinal directions,respectively.Ignoring colored noise will make the uncertainty of the deformation parameter estimation overly optimistic.PCA can significantly reduce the coloured noise,and thus reduce the uncertainty of deformation parameter estimation by about 73%.Moreover,the average difference between the daily periodic motion amplitudes of the monitoring points obtained by using GPS and BDS deformation time series is 1.65 mm.The use of GPS/BDS deformation time series is not only helpful to reduce the influence of coloured noise,but also can reduce the difference between amplitude analysis results obtained from GPS and BDS deformation time series. 展开更多
关键词 Long-span railway bridges GNSS deformation monitoring coloured noise PCA
下载PDF
Multiple chemical warfare agent simulant decontamination by self-driven microplasma 被引量:1
19
作者 陈恕彬 王世宇 +1 位作者 朱安娜 王瑞雪 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第11期12-21,共10页
Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supp... Low-temperature plasma is a green and high-efficiency technology for chemical warfare agent(CWA)decontamination.However,traditional plasma devices suffer from the problems of highpower composition and large power-supply size,which limit their practical applications.In this paper,a self-driven microplasma decontamination system,induced by a dielectric-dielectric rotary triboelectric nanogenerator(dd-r TENG),was innovatively proposed for the decontamination of CWA simulants.The microplasma was characterized via electrical measurements,optical emission spectra and ozone concentration detection.With an output voltage of-3460 V,the dd-r TENG can successfully excite microplasma in air.Reactive species,such as OH,O(1D),Hαand O3were detected.With input average power of 0.116 W,the decontamination rate of 2-chloroethyl ethyl sulfide reached 100%within 3 min of plasma treatment,while the decontamination rates of malathion and dimethyl methylphosphonate reached(65.92±1.65)%and(60.88±1.92)%after 7 min of plasma treatment,respectively.In addition,the decontamination rates gradually decreased with the increase in the simulant concentrations.Typical products were identified and analyzed.This study demonstrates the broad spectrum and feasibility of the dd-r TENG-microplasma for CWA elimination,which provides significant guidance for their practical applications in the future. 展开更多
关键词 triboelectric nanogenerator MICROPLASMA DECONTAMINATION chemical warfare agents simulants(Some figures may appear in colour only in the online journal)
下载PDF
Why is the beautyberry so colourful? Evolution,biogeography,and diversification of fruit colours in Callicarpa(Lamiaceae)
20
作者 Xing Liu Hui-Min Cai +3 位作者 Wen-Qiao Wang Wei Lin Zhi-Wei Su Zhong-Hui Ma 《Plant Diversity》 SCIE CAS CSCD 2023年第1期6-19,共14页
Fruit colour is essential to seed dispersal,speciation,and biological diversity in global ecosystems.The relationship between fruit-colour variation and species diversification has long been of interest in evolutionar... Fruit colour is essential to seed dispersal,speciation,and biological diversity in global ecosystems.The relationship between fruit-colour variation and species diversification has long been of interest in evolutionary biology,but remains poorly understood at the genus level.Here,we used Callicarpa,a typical representative of pantropical angiosperm,to analyse whether fruit colours are correlated with biogeographic distribution,dispersal events,and diversification rate.We estimated a time-calibrated phylogeny for Callicarpa and reconstructed ancestral fruit colour.Utilizing phylogenetic methods,we estimated the major dispersal events across the phylogenetic tree and the most likely fruit colours related to each dispersal event,and tested whether the dispersal frequencies and distances of the four fruit colours between major biogeographical areas were equal.We then tested whether fruit colours are correlated with latitude,elevation,and diversification rate.Biogeographical reconstructions showed that Callicarpa originated in the East Asia and Southeast Asia during the Eocene(-35.53 Ma) and diverse species diverged mainly in the Miocene and lasted into the Pleistocene.Large-scale dispersal events were significantly associated with violet-fruited lineages.Furthermore,different fruit colours were markedly correlated with different latitudes and elevations(e.g.,violet fruits were correlated with higher latitudes and elevations;red fruits and black fruits with lower latitudes;white fruits with higher elevations).Notably,violet fruits were statistically associated with highest diversification rates,driving fruit colour variation among different regions globally.Our results contribute to further understanding why fruit colour is so variable at the genus level of angiosperms in different areas around the world. 展开更多
关键词 CALLICARPA Fruit colour PHYLOGENY BIOGEOGRAPHY Dispersal DIVERSIFICATION
下载PDF
上一页 1 2 15 下一页 到第
使用帮助 返回顶部