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1.
山西五台山蓝花棘豆群落的数量分类和排序   总被引:10,自引:0,他引:10  
应用双向指示种分析法(TWINSPAN)和除趋势对应分析法(DCA)对山西五台山蓝花棘豆群落[Oxytropis coerulea (Pall.) DC.]进行了分类和排序.TWINSPAN分类结果将26个样方划分为8个群丛,即,蓝花棘豆 披针叶苔草 垂穗鹅观草群丛、蓝花棘豆 披针叶苔草群丛、蓝花棘豆 披针叶苔草 地榆群丛、蓝花棘豆群丛、蓝花棘豆 披针叶苔草 莓叶委陵菜群丛、蓝花棘豆 无芒雀麦群丛、蓝花棘豆 地榆群丛、蓝花棘豆 山蒿群丛,并分别对每个群丛生境进行了论述. DCA二维排序图较好地验证了TWINSPAN的分类结果,其纵、横坐标均反映了群丛所在环境的海拔等生态因子的梯度变化.种的DCA排序结果表明,群落中的建群种对海拔等生态因子有明显的指示作用,随海拔升高群落中的建群种由喜温耐旱植物演变为喜湿耐寒植物.  相似文献   

2.
金山  武帅楷 《生态学报》2021,41(10):4182-4193
为研究山西太岳山油松(Pinus tabuliformis)林过火后恢复初期林下草本植物群落结构,以2019年3月太岳山油松林火烧迹地为研究对象,采用群落相似性指数、多样性指数、稳定性系数、TWINSPAN数量分类和DCA排序等方法对群落组成、多样性、类型及稳定性等进行了研究。结果表明:(1)火烧迹地恢复初期以低矮灌木和多年生草本植物为主,其中又以地面芽植物占比最大。优势植物主要为大披针薹草(Carex lanceolata)和多花胡枝子(Lespedeza floribunda);(2)火烧迹地恢复初期各样地植物群落相似性系数和多样性指数相对较小,均匀度指数较大,但各样地恢复效果不尽相同,样地6和样地7的植物群落各项指标相对大于其他样地;(3)TWINSPAN数量分类将火烧迹地植物群落划分成:I.大披针薹草+南牡蒿(Artemisia eriopoda)+地榆(Sanguisorba officinalis)群丛、II.多花胡枝子+大披针薹草+二色棘豆(Oxytropis bicolor)群丛、III.多花胡枝子+大披针薹草+米口袋(Gueldenstaedtia verna)群丛、IV.多花胡枝子+大披针薹草+荠苨(Adenophora trachelioides)群丛、V.大披针薹草+白莲蒿(Artemisia stechmanniana)+狗娃花(Aster hispidus)群丛、VI.白莲蒿群丛、VII.大披针薹草+狗娃花+野艾蒿(Artemisia lavandulifolia)群丛;(4)DCA排序结果表明,火烧迹地恢复初期植物群落结构单一,沿样地和坡位变化较小,仅区分出样地7和其他样地两大类植物群落。(5)火烧迹地恢复初期植物群落处于不稳定的状态,但各样地间群落稳定性存在一定差别,其中样地1最大,样地5最小。总之,研究区植物群落处于演替初期,各样地间植物群落稳定性较差,多样性和整体相似性较小,但优势种群相似性较高,植物群落结构仍处于动态变化之中。研究揭示了太岳山火烧迹地恢复初期植物群落结构特征,积累了该区域火烧迹地植物群落生态学数据,同时可为该区域生态恢复提供科学依据。  相似文献   

3.
庄剑云  魏淑霞 《菌物学报》1995,14(Z1):153-157
本文报告采自四川西部的三种柄锈菌新记录.它们是披针苔草Carex lanceolata Boott上的栗褐苔草柄锈菌Puccinia caricis-brunneae Dietel,苔草Carex sp.上的小堆柄锈菌Pucciniamicrosora Koernicke ex Fuckel以及阳荷Zingiber strialatum Dicls上的姜黄柄锈菌Puccinia curcumae T.S. Ramakrishnan & Sundaram。每个种有简要讨论并附线条图.标本保藏在中国科学院微生物研究所真菌标本室(HMAS)。  相似文献   

4.
为了解释山西太岳山脱皮榆(Ulmus lamellosa)群落中物种的分布情况与该群落环境因子之间的相互关系,采用TWINSPAN数量分类和典范对应分析(CCA)与环境因子的变量分离进行讨论。结果表明,TWINSPAN将60个调查样方划分为7种群丛类型,体现了该脱皮榆群落主要以乔木脱皮榆和草本披针叶苔草(Carex lanceolata)为优势种。7种群丛类型与CCA排序结果一致,CCA排序第1轴主要体现了坡位和海拔;坡向与第2排序轴存在显著相关性。Monte Carlo检验结果表明,影响脱皮榆群落物种分布最主要的环境因子是海拔。在环境分离变量解释方面,环境因子解释了39.60%,空间因子解释了7.95%,空间因子与环境因子交互作用解释部分占10.89%。而其中不能解释的部分占41.56%。在该研究区,海拔对植物的分布有较好的解释力,其次是坡位和坡向。  相似文献   

5.
干扰对云顶山亚高山草甸群落物种多样性的影响   总被引:6,自引:0,他引:6  
放牧等干扰会对亚高山草甸群落的外貌、结构及功能造成影响。为了揭示在外界干扰下云顶山草甸群落的变化规律,对云顶山草甸进行群落学调查,共取45个样方(1×1 m)。在此基础上,应用TWINSPAN对草甸群落进行数量分类;运用丰富度指数、物种多样性指数和均匀度指数分析了不同程度干扰对草甸植物物种多样性的影响及其变化规律。结果表明:该草甸划分为6个群丛,受干扰程度中等的群丛3的丰富度、多样性以及均匀度都最高,受干扰程度轻的群丛1次之,而受干扰程度较重的群丛6最低。同时干扰对该草甸不同植物功能群及不同物种的影响趋势是不一致的。随着干扰程度加重,灌木和豆科等植物在群落中的优势地位逐渐减弱,甚至消失;禾草中的部分种如披针叶苔草(Carex lanceolata)等对干扰响应不明显;毒草和一些杂草种类在群丛中的优势地位明显上升。  相似文献   

6.
北疆盐碱地植物群落空间分布及物种多样性   总被引:1,自引:0,他引:1  
为探究盐碱地植物群落空间分布特征及群落间物种多样性的关系,根据对北疆盐碱地植物群落84个样点调查的数据,以各物种多度为指标,采用双向指示种分析方法(TWINSPAN)、除趋势对应分析法(DCA)、典范对应分析法(CCA)进行数量分类并分析群落分布与环境因子间关系和群落物种多样性及相似性变化特征。结果表明,TWINSPAN数量等级分类将84个样点的植物划分为11种类型。各群丛类型的物种多样性特征表现为群丛Ⅲ的多样性最大,群丛X多样性最小,且群丛Ⅲ多样性显著高于群丛X (P<0.05),群丛VⅡ均匀度最大,群丛X均匀度最小,且群丛Ⅲ均匀度显著高于群丛X(P<0.05),群丛I的丰富度最大,群丛X丰富度最小,且群丛I丰富度显著高于群丛X(P<0.05),在所有群丛中群丛Ⅲ所含有的植物种类最多,有26种;相似性特征为群丛V和群丛VⅡ的相似性最大,群丛V和群丛VⅡ物种间的竞争较小,群丛稳定性高;CCA排序结果表明,北疆盐碱地植物群落分布与海拔高度、多年平均温度、土壤酸碱度等因素有关,其中影响最大的是海拔高度,其次为多年平均温度、降水量、蒸发量和土壤电导率,地形因子坡度对各群丛分布影响不大;北疆盐碱地植物群落数量分类及物种多样性变化的分析对于揭示北疆盐碱地植物群落空间分布特征和新疆盐碱地植物种质资源调查及其保护具有重要的意义。  相似文献   

7.
选择长江源地区典型的紫花针茅草原作为研究对象,以大量的群落学样方调查为基础,采用TWINS-PAN、DCA、物种多样性,相关分析等多元数量分析方法,系统研究了紫花针茅草原的群落特征、物种多样性、群落与环境因子的关系.结果表明:(1)所调查的紫花针茅草原是物种组成相对简单、菊科和禾本科植物最多、北温带分布属为主体的草原群落;(2)长江源区紫花针茅草原群落可划分为四个群丛类型:紫花针茅+密丛棘豆群丛,紫花针茅+梭罗草群丛,紫花针茅+伊凡苔草群丛,紫花针茅+弱小火绒草群丛;(3)影响群丛分布的主要环境因子首先是海拔、经纬度等空间因子,其次是湿润度、降雨量等水分因子的影响;(4)紫花针茅+伊凡苔草群丛的物种多样性是研究区四个群丛中最高的.Simpson指数和均匀度指数受海拔、经纬度、平均降雨量、均湿润度等环境因子影响显著.该研究揭示了紫花针茅草原群落的内在规律.  相似文献   

8.
首次报到中国球兰属(Hoya R. Br.)一新记录种——披针叶球兰 (Hoya lanceolata Wall. ex D. Don), 该种原记载产自尼泊尔、印度、缅甸、泰国和越南。2018年该种在中国云南西部的铜壁关省级自然保护区发现有分布,凭证标本保存在HITBC。  相似文献   

9.
马晓勇  上官铁梁  张峰 《生态学报》2006,26(10):3372-3379
在中国植被分区上,山西恒山是温带草原地带与暖温带落叶阔叶林地带的交错区.采用TWINSPAN分类和DCA排序相结合的方法,对恒山南北坡植被类型进行了比较研究.TWINSPAN分类结果将南北坡的植被分别划分为16个群丛和20个群丛,分别隶属于16个和20个群系.DCA排序较好的印证了其分类结果:DCA排序第一轴反映海拔、温度的变化,南坡植被随海拔的升高,从耐旱的山蒿灌丛向寒温性的针叶林过渡,北坡由旱生的长芒草草原也向寒温性的针叶林过渡; 第二轴反映湿度的变化,排序轴从上到下,南坡由低海拔的山蒿群丛向高海拔的华北落叶松群丛,北坡是由长芒草、碱茅群丛向青杨群丛过渡.DCA排序结果显示,南北坡基带植被的群丛组成迥然不同,南坡基带为山蒿群丛、三裂叶绣线菊-山蒿+赖草群丛、虎榛子-披针叶苔草群丛,是落叶阔叶林破坏后形成的次生植被类型;北坡基带为长芒草群丛、碱茅+千里光群丛、三裂叶绣线菊-硬质早熟禾群丛、山菊+硬质早熟禾群丛,具有典型的草原植被特征,这与它们所处的植被带有较高的吻合度.南北坡随海拔升高,植被类型表现出明显的趋同性.对南北坡群系的比较结果表明:有4个群系为南北坡共有,但群丛数量存在较大的差异,三裂叶绣线菊群系、山蒿群系在南坡的群丛数要比北坡多,披针叶苔草群系在北坡的群丛数要比南坡多,华北落叶松群系分布大致相同.  相似文献   

10.
庄剑云 《菌物学报》1988,7(Z1):115-148
本文报告了中国莎草科植物的柄锈菌计33种.其中有2个新种,它们是双孔柄锈Puccinia biporosa sp. nov,和林氏苔草柄锈Puccinia caricis-lingii sp. nov.,均寄生于苔草属Carex.中国新记录种有13个.它们是大披针苔草柄锈Puccinia caricis-lanceolatae Y.Morimoto,云雾苔草柄锈Puccinia caricis-nubigenae Padwick ex AZmatullah Khan,疏毛苔草柄锈Puccinia caricis pilasae Miura ex Ito &Homma,假毒麦苔草柄锈Puccinia caricis-pseudololiaceae Homma,根状柄苔草柄锈Puecinia caricis rhizopodae Miura ex Ito &Homma,桑伯格苔草柄锈Puccinia caricis-thunbergii Homma,矮丛苔草生柄锈Puccinia humilicola Haslar,矮丛苔草柄锈Puccinia humilis Haslar,线形柄锈Puccinia lineariformis Syd,藻岩山柄锈Puccinia moiwensis Miura,奥皮茨柄锈Puccinia opiZii Bubak,林比苔草柄锈Puccinia yaramesuge Homma和珍珠茅生柄锈Puccinia scleriicola Arth..每个种均有形态描述并附图,有些种作了简要讨论,对过去的错误鉴定也作了订正.对苔草上的种还附有检索表.由于缺乏标本未能研究的种仅列出文献,寄主及产地.个别仅知春孢阶段的种作为暂定种列在附录中.本文所引证的标本均保藏在中国科学院微生物研究所真菌标本室.  相似文献   

11.
Systematic significance of mature embryo of bamboos   总被引:1,自引:0,他引:1  
The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.  相似文献   

12.
Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.  相似文献   

13.
The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.  相似文献   

14.
Twenty three species in 11 genera were examined in the field to determine hosts. OnlyStriga asiatica andSeymeria cassioides have a narrow host range being restricted to grasses and pines, respectively. These are the only species which cause pronounced and sometimes serious host damage. The other species attach to a great diversity of hosts.  相似文献   

15.
Intracellular cysteine aspartate-specific proteases (caspases) play both signaling and effector roles in realizing the program of cell death. Caspases function as proteolytic cascades unique for each cell type and signal triggering apoptosis. All parts of the proteolytic cascades are duplicated and controlled by feedback signals. Amplification cycles between pairs of caspases (the third and the sixth, the ninth and the third, the twelfth and the sixth, and others) help multiply the initial apoptotic signal. The presence of physiological inhibitors of apoptosis that directly interact with caspases creates a multilevel regulatory network of apoptosis in cell. The caspase proteolytic cascades are also regulated by sphingolipid secondary messengers, among them ceramide, sphingosine, and their phosphates. Moreover, an association of the caspase signaling with ubiquitin-dependent proteolysis is shown in cells. In particular, the use of extracellular activators and inhibitors of caspases allows irreversible activation of apoptosis in tumor cells or the prevention of apoptosis in cortical neurons under neurodegenerative diseases.  相似文献   

16.
17.
The Drosophila Pax6 homolog twin of eyeless (toy) is so far the first zygotically expressed gene involved in eye morphogenesis in Drosophila. The study of its expression during embryogenesis is therefore informative of the initial events of eye development in Drosophila. We have analyzed how the initial expression domain of toy at cellular blastoderm is regulated. We show that the three maternal patterning systems active in the cephalic region (the anterior, terminal and dorsal-ventral systems) cooperate with zygotically activated gap genes to shape the initial expression domain of toy. Whereas Bicoid, Dorsal and Torso signaling synergistically act as activators, Hunchback, Knirps and Decapentaplegic act as repressors.  相似文献   

18.
A molecular phylogeny of Hebeloma species from Europe   总被引:2,自引:1,他引:1  
In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.  相似文献   

19.
Sixteen new species are proposed in the generaAckermania, Dressleria, Epidendrum, Maxillaria, Oncidium, Rodriguezia, Sigmatostalix, andTrigonidium. All new species are illustrated.Maxillaria vittariifolia L. O. Williams is newly recorded for Peru. A key is provided forTrigonidium of Peru.Trigonidium loretoense Schltr. andT. peruvianum Schltr. are lectotypified.  相似文献   

20.
The reaction of chalcones and flavones with guanidine in ethanol results in 2-(2-aminopyrimidinyl-4)-phenols.  相似文献   

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