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Genetically Based Trait Differentiation but Lack of Trade-offs between Stress Tolerance and Performance in Introduced Canada Thistle

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Plant Communications 2020年第6期1卷 112-123页

作者： Kathryn A.Hodgins Alessia Guggisberg Kristin Nurkowski Loren H.Rieseberg School of Biological Sciences Monash UniversityMelbourneVICAustralia Department of Botany and Biodiversity Research Centre University of British ColumbiaVancouverBCCanada Department of Environmental Systems Science ETH ZurichZurichSwitzerland These authors contributed equally to this article

Trade-offs between performance and tolerance of abiotic and biotic stress have been proposed to explain both the success of invasive species and frequently observed size differences between native and introduced *** thistle seeds collected from across the introduced North American and the native European range were grown in benign and stressful conditions(nutrient stress,shading,simulated herbivory,drought,and mowing),to evaluate whether native and introduced individuals differ in performance or stress *** additional experiment assessed the strength of maternal effects by comparing plants derived from field-collected seeds with those derived from clones grown in the *** populations tended to be larger in size,but no trade-off of stress tolerance with performance was detected;introduced populations had either superior performance or equivalent trait values and survivorship in the treatment common *** also detected evidence of parallel latitudinal clines of some traits in both the native and introduced ranges and associations with climate variables in some treatments,consistent with recent climate adaptation within the introduced *** results are consistent with rapid adaptation of introduced populations,but,contrary to predictions,the evolution of invasive traits did not come at the cost of reduced stress tolerance.

关键词： biological invasion eica adaptation trait evolution plasticity Canada thistle

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Does higher ploidy level increase the risk of invasion?A case study with two geo-cytotypes of Solidago gigantea Aiton(Asteraceae)

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Journal of Plant Ecology 2018年第2期11卷 317-327页

作者： David U.Nagy Szilvia Stranczinger Aliz Godi Anett Weisz Christoph Rosche Jan Suda Mark Mariano Robert W.Pal Department of Ecology Institute of BiologyFaculty of SciencesUniversity of PécsH-7624 PécsIfjúság u.6Hungary Department of Botany Institute of BiologyFaculty of SciencesUniversity of PécsH-7624 PécsIfjúság u.6Hungary Working Group:Plant Ecology Institute of Biology/Geobotany and Botanical GardenMartin Luther University Halle-WittenbergAm Kirchtor 1D-06108 HalleGermany Department of Botany Faculty of ScienceCharles University in PragueBenátská2CZ-12801 PragueCzech Republic and Institute of BotanyThe Czech Academy of SciencesZámek 1CZ-25243 PruhoniceCzech Republic Department of Biological Sciences Montana TechMontana Tech of the University of Montana1300 W Park StMT 59701 ButteUSA

Aims Understanding the role of genetics in biological invasions has become an important aspect for modern plant *** studies suggest that increased ploidy level benefits the success of an invasive species,but the basis for this phenomenon is not fully *** its native,North American range,Solidago gigantea has three geo-cytotypes comprising di-,tetra-and hexa-ploid populations,while in Europe,where it is highly invasive,*** stands are composed primarily of tetraploid *** study investigates whether North American hexaploids can induce a greater risk of invasion,due to their higher perfor-mance in a non-native range,as compared to the existing tetra-ploids of that *** We performed greenhouse and common garden experiments along with microsatellite analyses to test whether differences in chromo-some number and origin of the species mean superior fitness in the introduced *** Findings Genetic diversity was significantly higher in the native hexaploid popula-tions(A_(R)=6.04;H_(e)=0.7794),rather than the non-native tetraploid pop-ulations(A_(R)=4.83;H_(e)=0.6869).Furthermore,differentiation between geo-cytotypes was moderate(ρST=0.1838),which was also confirmed by their clear segregation in principal component analysis and structure analyses,proving their different genetic *** contrast to genetic diversity,the non-native tetraploid geo-cytotype performed better in the common garden experiment,implying that higher genetic diversity does not always mean better *** results suggest that native hexa-ploids do not present a greater risk,as assessed by their performance in the introduced range,when compared to the non-native tetraploids,as was suggested by previous ***,their introduction is still undesirable due to their different genetic structure,which,through hybridization,could give a new drive to the invasion of ***.

关键词： eica plant invasion microsatellite ecotype polyploidy

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基于ICA和EMD的睡眠脑电图预处理算法的研究

基于ICA和EMD的睡眠脑电图预处理算法的研究

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作者：彭云重庆大学

学位级别：硕士

利用睡眠脑电图(EEG)可提取大量的生理信息和疾病信息。然而，在头皮采集到的睡眠EEG一般比较微弱，不可避免地会受到各种噪声干扰。尤其是ECG、EOG和EMG等生理伪迹的干扰，由于它们与睡眠EEG的频谱重叠，给睡眠EEG的提取带来了极大的... 详细信息

利用睡眠脑电图(EEG)可提取大量的生理信息和疾病信息。然而，在头皮采集到的睡眠EEG一般比较微弱，不可避免地会受到各种噪声干扰。尤其是ECG、EOG和EMG等生理伪迹的干扰，由于它们与睡眠EEG的频谱重叠，给睡眠EEG的提取带来了极大的困难。所以研究如何消除睡眠EEG的生理伪迹对高精度提取睡眠EEG具有重大意义。独立分量分析(ICA)能分离出多维观测信号中的统计独立非高斯成分，经验模态分解(EMD)是一种自适应局域波信号处理技术，适合提取局部瞬时信息。它们用于EEG信号预处理，都有局限性。本论文针对睡眠EEG的非线性非平稳特性，提出了结合ICA和EMD的新方法来减少睡眠EEG的生理伪迹，试验表明，该新方法发挥了两种方法各自的优点而避免了各自的局限性。本论文首先分析了睡眠EEG生理伪迹的产生原因和主要特征，介绍了各种方法的优缺点及其局限性。然后介绍了ICA和EMD基本原理，分析了基于负熵的FastICA算法和EMD算法性能的有效性。试验表明，针对不同记录的EEG，采用ICA可分离出多导联EEG的生理伪迹，运用EMD滤波可实现单导EEG的伪迹消除。与小波分解去除EEG工频干扰相比，EMD滤波能更好地保留EEG的瞬时特性。而ICA有两个缺陷：会引起部分EEG的缺失，人工判别伪迹成分，耗时而不可靠。因而我们提出了一种将ICA和EMD相结合的新方法，称为eica。与FastICA算法和ICA与小波相结合(WICA)算法相比，eica算法能有效地恢复遗漏在伪迹中的神经信息和伪迹频段外的脑电活动信号。对于真实睡眠EEG，eica算法能有效消除生理伪迹，而且很好地保留了原始睡眠EEG其它成分的局部特性。总之，本论文针对生理伪迹干扰与睡眠EEG的频谱重叠情况，针对睡眠EEG的非线性非平稳特性，分析了传统方法的局限性，充分利用ICA和EMD各种的优点，提出了结合ICA和EMD的新方法来减少睡眠EEG的生理伪迹，研究结果表明，该新方法发挥了两种方法各自的优点而避免了各自的局限性，为提取睡眠EEG提供了有效途径。

关键词：睡眠EEG 生理伪迹消除 eica 独立分量分析经验模态分解

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