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陕西红碱淖遗鸥(Larus relictus)繁殖种群动态 被引量:11
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作者 肖红 张治来 +1 位作者 王中强 王艳 《陕西师范大学学报(自然科学版)》 CAS CSCD 北大核心 2006年第B03期83-86,共4页
报道了红碱淖自2000年首次记录遗鸥(Larus relictus)以来随后5年间对其繁殖种群数量变化的监测结果.2005年,红碱淖遗鸥繁殖种群达2460巢,成为继内蒙古桃力庙-阿拉善湾海子和敖拜淖尔之后目前最大遗鸥种群的繁殖地.结合历年来红碱淖由... 报道了红碱淖自2000年首次记录遗鸥(Larus relictus)以来随后5年间对其繁殖种群数量变化的监测结果.2005年,红碱淖遗鸥繁殖种群达2460巢,成为继内蒙古桃力庙-阿拉善湾海子和敖拜淖尔之后目前最大遗鸥种群的繁殖地.结合历年来红碱淖由于气候变化引起的水位及湖心岛变化情况,在未来5-10年间,红碱淖仍将是遗鸥重要繁殖地之一. 展开更多
关键词 遗鸥 繁殖种群 动态 红碱淖
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遗鸥(Larus relictus)繁殖生态研究 被引量:19
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作者 张荫荪 丁文宁 +2 位作者 陈容伯 吴勇 梁拴柱 《动物学报》 SCIE CAS CSCD 1993年第2期154-159,共6页
本文对世界濒危鸟类—遗鸥的繁殖地生境、留居时间和分布、繁殖行为、种群数量、食性及天敌等做了较系统的记述。于繁殖地,所见遗鸥皆参与繁殖,性比1:1;有581巢,分属8个巢群,巢的密度0.121—0.547巢/m^2,每巢含卵1—4枚,种群繁殖期约两... 本文对世界濒危鸟类—遗鸥的繁殖地生境、留居时间和分布、繁殖行为、种群数量、食性及天敌等做了较系统的记述。于繁殖地,所见遗鸥皆参与繁殖,性比1:1;有581巢,分属8个巢群,巢的密度0.121—0.547巢/m^2,每巢含卵1—4枚,种群繁殖期约两个月,孵化期24—26天,孵化率100%。 展开更多
关键词 遗鸥 繁殖 生态
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Forest characteristics and population structure of Glyptostrobus pensilis, a globally endangered relict species of southeastern China 被引量:1
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作者 Cindy Q. Tang Yongchuan Yang +14 位作者 Arata Momohara Huan-Chong Wang Hong Truong Luu Shuaifeng Li Kun Song Shenhua Qian Ben LePage Yi-Fei Dong Peng-Bin Han Masahiko Ohsawa Buu Thach Le Huu Dang Tran Minh Tri Dang Ming-Chun Peng Chong-Yun Wang 《Plant Diversity》 SCIE CAS CSCD 2019年第4期237-249,共13页
The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. F... The Chinese water pine Glyptostrobus pensilis is the sole surviving species of the genus Glyptostrobus. It is endemic to southern China, central Vietnam, and eastern Laos, and today it is nearly extinct in the wild. Forest community characteristics and population structure of G. pensilis in China have remained un-known up to now. We investigated six swamp forest stands and analyzed their forest community characteristics (i.e. vertical stratification, species composition, and diversity) and population structure, including the frequency distribution of DBH (diameter at breast height) and age-classes as found in Fujian Province, southeastern China. The vertical stratifications of all the forest stands were rather simple. The remaining wild specimens ranged from roughly 15 to some 357 years for an average of ca. 85 years, with only a few individuals less than 20 years old. Compared with the stands and populations of G. pensilis in Vietnam, the taxonomic compositions of the stands in the two regions were different, except for the dominant species-G. pensilis. The Shannon-Wiener index showed the overstory of each stand had much lower diversity (0.26 on average) in Fujian Province than that (1.97 on average) in Vietnam, whereas the diversity indices were about the same (around 2.41) for the understories in the two regions. Furthermore, we discovered 18 G. pensilis seedlings at the study sites in Fujian Province. This discovery demonstrates that G. pensilis regeneration is extremely poor and its populations are declining, although these populations are rela-tively healthier than those in Vietnam. 展开更多
关键词 Age-class Fujian Province Glyptostrobus Regeneration relict plant VIETNAM
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Seasonal changes in the number of Relict Gull (Larus relictus) at Ebinur Lake, Western China
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作者 Kedeerhan BAYAHEN 《Journal of Arid Land》 SCIE 2010年第2期151-155,共5页
The Relict Gull(Larus relictus) is recognized as a vulnerable species,with a worldwide population of about 6,000 individuals.Always inhabiting the extreme arid regions of Central Asia,their migratory routes and winter... The Relict Gull(Larus relictus) is recognized as a vulnerable species,with a worldwide population of about 6,000 individuals.Always inhabiting the extreme arid regions of Central Asia,their migratory routes and winter grounds are unclear.This research focused on distribution sites,habitat,behavior,population size and seasonal changes of Relict Gull.Line transects and point counts in every month were used to investigate the gulls around the Ebinur Lake.The result showed Relict Gull was summer visitor to Xinjiang,Western China.Population curve with a single peak was obtained.This gull appeared in early April and was 63 individuals(1% of the global population).The number remained stable from May to July in 2009.The discovery of fledglings indi-cates that Relict Gull may breed here.They left Ebinur Lake in August.Relict Gull in Ebinur Lake should belong to the Central Asian subpopulation,which was the most westerly record in China. 展开更多
关键词 relict Gull(Larus relictus) POPULATION seasonal change Ebinur Lake Central Asia
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遗鸥(Larus relictus)繁殖群在内蒙古东部的新发现 被引量:15
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作者 薛文 马俊 +3 位作者 布和 陈容伯 群力 李瑶 《内蒙古大学学报(自然科学版)》 CAS CSCD 1998年第5期694-696,共3页
在内蒙古东部草原地区新发现遗鸥繁殖群.记述了遗鸥的繁殖地生境,繁殖习性、食性、动物群落结构等内容;讨论了遗鸥对繁殖地选择的必要条件.
关键词 鸥形目 遗鸥 繁殖群 内蒙古
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Sedimentary Characteristics of Relict Deposits on the Western South Yellow Sea
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作者 WEN Chun LIU Jian +3 位作者 WANG Hong XU Gang QIU Jiandong ZHANG Junqiang 《Journal of Ocean University of China》 SCIE CAS 2014年第2期205-214,共10页
Integrated studies of vertical sedimentary sequences, grain sizes, and benthic foraminifera and ostracoda, in combination with AMS 14C dating, and 210Pb and 137Cs analysis were carried out in three vibracores taken fr... Integrated studies of vertical sedimentary sequences, grain sizes, and benthic foraminifera and ostracoda, in combination with AMS 14C dating, and 210Pb and 137Cs analysis were carried out in three vibracores taken from the area of relict deposits on the western South Yellow Sea. The relict sands, which are about 0.4 m thick, overlie on the Early Holocene coastal marsh or tidal flat deposits with an evident erosional interface in between. The middle and upper parts or sometimes the whole of the relict sands have been reworked under the modern dynamic environment. The sedimentation rate varies between 0.20–0.30 cm year-1. The relict sands show a bimodal grain-size distribution pattern in frequency curves, with a sharp peak in the coarse fraction between 3Φ and 4Φ and a secondary peak in the fine fraction of about 7Φ. Of the benthic foraminiferal and ostracod assemblages, the reworked relict sands are characterized by the mixing of the nearshore euryhaline shallow-water species and deeper water species. The erosional interface at the bottom of the relict sands is considered as a regional ravinement surface formed during the transgression in the Early Holocene due to shoreface retreating landwards. The relict sands were accumulated on the ravinement surface during the transgression in the deglaciation period as lag deposits after winnowing and reworking by marine dynamic processes. And the secondary peak of fine fraction in the frequency curve for the relict sands suggests the input of fine-grained sediments during the reworking process. As the conclusion, the relict sands in the study area are interpreted as a type of reworked relict sediments. 展开更多
关键词 南黄海 存款 沉积特征 底栖有孔虫 西方 海洋动力过程 频率曲线 残留砂
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A possible relict mantle wedge: Geochemical evidence from Paleogene volcanics in North China 被引量:3
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作者 Bolin Cong Jinghui Guo Wenjun Liu 《Chinese Science Bulletin》 SCIE EI CAS 2001年第22期1917-1922,共6页
The major and trace element and isotopic composition were analyzed for the Paleogene volcanics in North China dated by the K-Ar method. The geochemical data show that most volcanics are in calc-alkaline series and the... The major and trace element and isotopic composition were analyzed for the Paleogene volcanics in North China dated by the K-Ar method. The geochemical data show that most volcanics are in calc-alkaline series and the minor is in alkaline series. They differ obviously from Neogene and Quaternary volcanics in geochemistry. In particular, the Paleogene volcanics from the southern part of North China were derived from enriched lithospheric mantle (EMU), which were likely to be a relict mantle wedge formed during the subduction of the Yangtze plate into the North China plate in late Triassic (Indo- Sinian). 展开更多
关键词 VOLCANICS relict MANTLE WEDGE geochemistry PALEOGENE North China.
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comIntraspecific variation in heritable secondary metabolites and defensive strategies in a relict tree
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作者 Adara Pardo Yonatan Cáceres Fernando Pulido 《Journal of Plant Ecology》 SCIE CSCD 2018年第2期256-265,共10页
Aims Key herbivory interaction traits such as plant defensive compounds may differ among populations of a single species due to the spatial variation in herbivore feeding guilds and the strength of the interac-tion.Mo... Aims Key herbivory interaction traits such as plant defensive compounds may differ among populations of a single species due to the spatial variation in herbivore feeding guilds and the strength of the interac-tion.Moreover,the genealogy of population lineages could represent an additional source of variation interacting with the predominant eco-clinal trends.We tested for the existence of genetically based intraspecific variation in chemical defence profiles across the range of the relict tree Prunus lusitanica L.Additionally,we investigated geographical variation in defence inducibility and tested for the exist-ence of a trade-off between qualitative and quantitative defences.Methods We conducted a greenhouse experiment where 210 plants were grown under a common environment,comprising 10 different pop-ulations throughout the distribution range of the species and span-ning three separate regions:iberia,Morocco and Macaronesia.To test for the inducibility of defences,we artificially defoliated plants.Three treatments were established within each population:undam-aged,defoliated and sampled after 2 h,and defoliated and sampled after 72 h.The concentration of cyanogenic glycosides(prunasin)and phenolics was determined in leaf samples for all treatments.Important findings Basal levels of cyanogenics and phenolics significantly differed among populations and regions across the range of P.lusitanica,with this variation having a heritable basis.Cyanogenics(pruna-sin)were significantly higher in ancient Macaronesian populations,while phenolic concentrations were larger in iberia.The higher cyanogenic levels found in Macaronesia could be a consequence of the known stronger herbivory pressure in the islands than in iberia or the likely longer coevolutionary history with herbivores in this region.These findings indicate that the geographical variation of key ecological traits such plant chemical defences can be imprinted by phylogeographical signals,particularly in relict species.Regarding defence inducibility,prunasin increased after simulated herbivory whereas phenolics mostly decreased after defoliation.Variation in defence inducibility across populations and regions was evident,although no consistent patterns related to the variation in herbivore feeding guilds were observed,particularly among regions with and without ungulate browsing pressure.Finally,a trade-off among induced levels of qualitative(prunasin)and quantitative(phenolics)defences was detected in one of the defoliated treatments,likely as a result of a stronger resource limitation in damaged plants. 展开更多
关键词 HERBIVORY intraspecific variation PHYLOGEOGRAPHY plant defences relict flora
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Native and exotic seed dispersal by the stone marten(Martes foina):implications for the regeneration of a relict climactic forest in central Portugal
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作者 Lúcia PEREIRA Ana VASQUES +3 位作者 Paula MAIA Maria João RAMOS PEREIRA Carlos FONSECA Milena MATOS 《Integrative Zoology》 SCIE CSCD 2019年第3期280-292,共13页
The stone marten(Martes foina)is a carnivorous mammal that often consumes fleshy fruits,thus potential­ly promoting seed dispersion.The present study was developed in Bussaco National Forest,central Portugal,and ... The stone marten(Martes foina)is a carnivorous mammal that often consumes fleshy fruits,thus potential­ly promoting seed dispersion.The present study was developed in Bussaco National Forest,central Portugal,and aimed to assess the potential role of the stone marten in dispersing native and exotic plants in different for­est landscape types.Seeds from stone marten scats and fleshy fruits were collected monthly and were thereafter identified and sowed in a nursery,following a randomized experimental setup.Plant emergence was monitored fortnightly.Generalized linear models were used to test for differences in time and success of emergence be­tween seeds from scats and fruits of 3 native species(Rubus ulmifolius,Arbutus unedo and Celtis australis)and 1 exotic plant species with invasive behavior(Prunus laurocerasus).Fruit consumption by the stone martens significantly increased and accelerated the germination of the native R.ulmifolius but had no effect on the other 2 native species or on the invasive species.This suggested that stone martens contribute to gene flow and forest regeneration by dispersing native plant seeds.However,although the germination was not enhanced in the in­vasive species,the preference of stone martens for these fruits may potentially contribute to the proliferation of P.laurocerasus.Our study represents a contribution to better understanding the fauna and flora interactions,en­abling for a more conscious and effective decision-making in forest management. 展开更多
关键词 GERMINATION invasive species Martes foina Prunus laurocerasus relict climactic forest
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西鄂尔多斯4种孑遗植物叶片解剖结构及适应性分析
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作者 曹恭祥 邢钰坤 +4 位作者 邢钟毓 李银祥 杨跃文 闫峰 曹建军 《内蒙古林业科技》 2023年第4期41-45,共5页
为了解西鄂尔多斯地区濒危孑遗植物对干旱环境的适应性,本研究采用石蜡切片法,观察研究4种孑遗植物叶片解剖结构。结果显示:相同生境下4种植物叶片结构存在较大差异。四合木(Tetraena mongolica)叶片解剖呈半月形,沙冬青(Ammopiptanthus... 为了解西鄂尔多斯地区濒危孑遗植物对干旱环境的适应性,本研究采用石蜡切片法,观察研究4种孑遗植物叶片解剖结构。结果显示:相同生境下4种植物叶片结构存在较大差异。四合木(Tetraena mongolica)叶片解剖呈半月形,沙冬青(Ammopiptanthus mongolicus)叶片解剖呈扁平状,鄂尔多斯半日花(Helianthemum ordosicum)叶片正常状态下卷曲,霸王(Sarcozygium xanthoxylon)叶片解剖呈椭圆状条形。4种植物都具有典型的等面叶,上下表皮均有栅栏组织和气孔,叶片厚度大,角质层增厚,植株储水保水能力强,可通过改变叶表面积、调节气体交换、减少蒸腾作用,实现对干旱环境的适应,4种植物对干旱生境有很强的适应性。本研究可为揭示孑遗植物的抗旱机理以及濒危植物保护提供理论支撑。 展开更多
关键词 西鄂尔多斯 孑遗植物 叶片解剖结构
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Ether as the Fundamental Substance of the Creation of the Universe
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作者 Avas Khugaev Eugeniya Bibaeva 《Journal of Applied Mathematics and Physics》 2023年第12期3800-3825,共26页
The paper analyzes the concept of Ether and substantiates the necessity of its existence as a physical reality, which arises within the framework of the concept developed by the authors of the work. The authors come t... The paper analyzes the concept of Ether and substantiates the necessity of its existence as a physical reality, which arises within the framework of the concept developed by the authors of the work. The authors come to the conclusion that the existence of Ether in two different forms, plays an exceptional role in the formation of Dark Matter and Dark Energy and leads to the emergence of exotic cosmological structures and their hierarchy in energy, temporal, and spatial scale. The mechanism of the formation of physical structures before the Big Bang and their further evolution, up to the formation of worlds of galaxies and stars, is considered. The necessity of the emergence of exotic structures, such as 3 spheres of the Primary Relict, is shown, its structure and dynamic properties leading to the formation of Order from Chaos are considered. The role of the 1st and 2nd type Ether in the formation of the mechanism of transformation of cosmic energies and quantum phase transitions, in the process of the birth and evolution of the Universe is discussed. The conclusion is made about the existence of universal properties of matter, at the level of Macro and Microcosms, and a multidimensional cosmological model with an isothermal temperature distribution is constructed, leading to a discrete distribution of matter separated by transitions, by analogy with Black-and-White Holes. It is shown that the postulate of the constancy of the speed of light in any inertial system is a consequence of the principle of covariance. 展开更多
关键词 ETHER Speed of Light Black and White Hole Quantum Transitions Primary relict Chaos and Order Primary Atom Big Bang Dark Matter and Energy Borromeo Rings
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西鄂尔多斯珍稀濒危沙冬青及伴生种对土壤特征的影响 被引量:3
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作者 吴惠敏 党晓宏 +2 位作者 翟波 魏亚娟 李小乐 《干旱区研究》 CSCD 北大核心 2023年第5期767-776,共10页
为探究荒漠灌丛及其伴生种对灌丛下土壤粒径、养分空间异质性的影响,以西鄂尔多斯国家级自然保护区内沙冬青(Ammopiptanthus mongolicus)-霸王(Sarcozygium xanthoxylon)混生群落、单株沙冬青为研究对象,以周围无植被覆盖的裸沙地为对照... 为探究荒漠灌丛及其伴生种对灌丛下土壤粒径、养分空间异质性的影响,以西鄂尔多斯国家级自然保护区内沙冬青(Ammopiptanthus mongolicus)-霸王(Sarcozygium xanthoxylon)混生群落、单株沙冬青为研究对象,以周围无植被覆盖的裸沙地为对照(CK),对比分析不同灌丛分布类型下土壤粒度特征、养分积累变化及养分与粒度组成的作用关系。结果表明:(1)单株沙冬青土壤黏粒、粉粒、细砂的体积百分含量较沙冬青-霸王分别增加0.8%、0.8%、0.71%。随灌丛种类减少,土壤粒径依次变细,分选性变差,分形维数变小,土壤颗粒分布逐渐不对称,颗粒组成向细粒物质集中。(2)土壤有机质、碱解氮含量随灌丛种类的增多分别增加了1.85 g·kg^(-1)、8.18 mg·kg^(-1)。单株沙冬青对有机质、速效磷的富集作用较沙冬青-霸王更强,对碱解氮的积累效果较沙冬青-霸王稍差。(3)沙冬青-霸王土壤速效磷含量与细砂含量呈显著正相关(P<0.05),沙冬青土壤碱解氮、速效钾与粗砂呈显著正相关(P<0.05)。沙冬青-霸王、沙冬青可有效促进土壤颗粒细粒化、显著改善土壤养分,但伴生种霸王的存在降低了沙冬青对有机质和速效磷的富集作用。 展开更多
关键词 土壤机械组成 养分富集 孑遗植物 西鄂尔多斯地区
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江西齐云山长苞铁杉种群特征与种间联结研究
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作者 汪志培 黄世贵 +2 位作者 朱祥龙 卢建 吴治明 《生物灾害科学》 2023年第4期500-509,共10页
【目的】探讨江西齐云山国家级自然保护区长苞铁杉(Nothotsuga longibracteata)种群与种间联结特征,为保护区珍稀孑遗植物的监测与保护提供科学依据。【方法】根据前期踏查的结果,在江西齐云山国家级自然保护区内选择长苞铁杉集中分布区... 【目的】探讨江西齐云山国家级自然保护区长苞铁杉(Nothotsuga longibracteata)种群与种间联结特征,为保护区珍稀孑遗植物的监测与保护提供科学依据。【方法】根据前期踏查的结果,在江西齐云山国家级自然保护区内选择长苞铁杉集中分布区域,建立15个40m×40m的长苞铁杉群落固定样地,对长苞铁杉种群和种间联结进行分析。【结果】(1)长苞铁杉个体数量总体随着龄级的增加而减少,年龄结构呈“金字塔”型。(2)长苞铁杉在Ⅱ、Ⅶ和Ⅻ龄级存在3个死亡高峰期。(3)长苞铁杉群落优势树种总体呈显著正联结,其中长苞铁杉与杉木(Cunninghamia lanceolata)呈显著正相关,而与大果马蹄荷(Exbucklandia tonkinensis)、圆萼折柄茶(Stewartia crassifolia)呈显著负相关。【结论】齐云山保护区长苞铁杉种群呈增长趋势,但种群生存压力较大,应提前采取相应的干预措施,以预防未来种群出现衰退。长苞铁杉群落主要物种间总体呈显著正相关,在保护过程中需重点关注与长苞铁杉呈负相关的物种,可适当进行人为干预,以防止这些物种过度增长导致长苞铁杉自然更新出现困难。 展开更多
关键词 齐云山保护区 长苞铁杉 孑遗植物 种群特征 种间联结
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关于基性岩墙群的U-Pb SHRI MP地质年代学的探讨——以鲁西莱芜辉绿岩岩墙为例 被引量:34
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作者 侯贵廷 刘玉琳 +1 位作者 李江海 金爱文 《岩石矿物学杂志》 CAS CSCD 北大核心 2005年第3期179-185,共7页
锆石成因研究是判断锆石年龄意义的基础。本文以鲁西隆起区莱芜辉绿岩岩墙的锆石U_PbSHRIMP年代学研究为例,从锆石成因入手探讨基性岩墙群的锆石地质年代学分析中出现的一些问题。本区基性岩墙内存在两类锆石,一种是从围岩捕获的残余锆... 锆石成因研究是判断锆石年龄意义的基础。本文以鲁西隆起区莱芜辉绿岩岩墙的锆石U_PbSHRIMP年代学研究为例,从锆石成因入手探讨基性岩墙群的锆石地质年代学分析中出现的一些问题。本区基性岩墙内存在两类锆石,一种是从围岩捕获的残余锆石,其谐和年龄为2 5 37±16Ma ;另一种为岩墙原生的岩浆锆石,谐和年龄为1139±2 5Ma和115 7±18Ma ,说明岩墙侵位时代约为中元古代。基性岩墙内原生岩浆锆石很少,因此,要谨慎分析锆石的成因类型和年龄谱系,不能简单地以大多数数据的平均年龄为准,而应该以地层接触关系和岩浆岩交切关系为基本证据,结合各种同位素绝对年龄的分析来确定基性岩墙的侵位时代。 展开更多
关键词 基性岩墙 残余锆石 岩浆锆石 U—Pb SHRIMP年代学
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孑遗植物杜仲的遗传多样性RAPD分析和保护策略研究 被引量:23
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作者 王瑷琦 黄璐琦 +3 位作者 邵爱娟 崔光红 陈敏 佟长辉 《中国中药杂志》 CAS CSCD 北大核心 2006年第19期1583-1586,共4页
目的:进行杜仲群体遗传多样性的研究。方法:采用随机扩增多态DNA(RAPD)方法对杜仲的16个群体、260个个体进行遗传多样性分析。结果:用10个随机引物共扩出110条清晰条带,其中多态性条带为106条,总的多态位点百分率为96.36,平均多态位点... 目的:进行杜仲群体遗传多样性的研究。方法:采用随机扩增多态DNA(RAPD)方法对杜仲的16个群体、260个个体进行遗传多样性分析。结果:用10个随机引物共扩出110条清晰条带,其中多态性条带为106条,总的多态位点百分率为96.36,平均多态位点百分率为38.92。Ne’is基因多样性指数H=0.246 1,Shannon’s多态性信息指数I=0.386 8。基因分化系数Gst=0.424 4。结论:杜仲种内具有丰富的遗传多样性,而不同群体内部的遗传多样性低。遗传分化分析表明杜仲群体间已发生了高度的遗传分化,因此,生物多样性保护时应尽可能保护更多的种群。 展开更多
关键词 杜仲 RAPD 遗传多样性 保护
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孑遗植物四合木(Tetraena mongolica)的濒危肇因与机制 被引量:26
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作者 智颖飙 杨持 +5 位作者 王中生 安树青 王再岚 李红丽 宿志安 王强 《生态学报》 CAS CSCD 北大核心 2008年第2期767-776,共10页
对我国特有单属种孑遗植物四合木(Tetraena mongolica Maxim)的地理分布、生境条件、种群数量动态、空间分布格局、种间关系、种群的生命表、生殖力表、有性生殖、无性繁殖和遗传变异等种群生态学特征及其濒危肇因进行了系统分析。研究... 对我国特有单属种孑遗植物四合木(Tetraena mongolica Maxim)的地理分布、生境条件、种群数量动态、空间分布格局、种间关系、种群的生命表、生殖力表、有性生殖、无性繁殖和遗传变异等种群生态学特征及其濒危肇因进行了系统分析。研究结果表明:四合木种群为高群集分布,种群曲线属Leak凸型。年龄结构不合理,其存活曲线接近于Deevey毢型,且将演化为小种群,群落内的生境异质性显著,种群处于不稳定阶段。四合木从开花期到结果期,生殖分配(RA)呈下降的趋势,生殖过程中胚胎发生败育、种子向幼苗难以转化使其有性生殖受阻,生活史趋于断裂,是最终导致其濒危的重要内因。分布区城市化、工业化以及过度放牧等原因造成其种群孤立和生境破碎化是物种导致濒危的外因,四合木生态适应性和生境适宜性下降造成遗传多样性逐步丧失。同时提出对我国特有植物四合木进行异地保护的可能性与必然性。 展开更多
关键词 四合木 孑遗植物 濒危机制 胚胎败育 异地保护
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白云岩的残余结构及由此引发的孔隙分类问题 被引量:16
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作者 张学丰 蔡忠贤 +2 位作者 李林 谷晓丹 赵文光 《沉积学报》 CAS CSCD 北大核心 2011年第3期475-485,共11页
对碳酸盐岩的结构分类方法进行了评述,但目前的分类并未对白云岩的残余结构问题进行充分论述。为了能更准确地恢复岩相古地理和进行精细的成岩研究,有必要对残余结构进行细分。白云岩的残余结构是由于原始粒屑结构的灰岩,经白云岩化、... 对碳酸盐岩的结构分类方法进行了评述,但目前的分类并未对白云岩的残余结构问题进行充分论述。为了能更准确地恢复岩相古地理和进行精细的成岩研究,有必要对残余结构进行细分。白云岩的残余结构是由于原始粒屑结构的灰岩,经白云岩化、重结晶、溶蚀、胶结等成岩作用之后,岩石原始结构遭到不同程度的破坏,但仍残留有部分原始结构信息而形成的。根据颗粒与胶结物的可识别性和颗粒内部结构的保存程度,把残余结构划分为残余粒屑结构、残余粒形结构和残余影像结构,并分别给出相应的判别标准、鉴定特征、描述方法和相关实例。残余结构白云岩的孔隙分类也与原始粒屑结构灰岩有所不同。在Choquette和Pray(1970)孔隙分类方法的基础上,把残余结++构白云岩的孔隙分为组构选择性孔隙、部分组构选择性和非组构选择性孔隙三大类。其中,组构选择性孔隙包括粒内孔(含铸模孔)、粒间孔和晶间孔三大类,其中前两者还包括不同形态的亚类;非组构选择性孔隙主要包括溶蚀扩大孔;非组构选择性孔隙按孔隙形态和大小划分为溶孔、溶沟、溶洞、裂缝和角砾孔隙。 展开更多
关键词 白云岩 残余结构 孔隙分类
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孑遗植物水杉的遗传多样性研究 被引量:54
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作者 李晓东 黄宏文 李建强 《生物多样性》 CAS CSCD 2003年第2期100-108,共9页
采用随机扩增多态DNA(RAPD)方法对孑遗植物水杉 (Metasequoiaglyptostroboides)的 8个居群 (包括 6个孑遗居群和 2个人工栽培居群 )的 48个个体进行了遗传多样性研究。用 16个随机引物共扩增出清晰谱带 5 7条。孑遗居群平均多态位点百... 采用随机扩增多态DNA(RAPD)方法对孑遗植物水杉 (Metasequoiaglyptostroboides)的 8个居群 (包括 6个孑遗居群和 2个人工栽培居群 )的 48个个体进行了遗传多样性研究。用 16个随机引物共扩增出清晰谱带 5 7条。孑遗居群平均多态位点百分率为 38.6 %。各居群多态位点百分率差异显著 ( 10 .5 3%~ 33 .33 % ) :湖北利川的小河和桂花 2个居群较高 ,分别是 33 .33%和 31.5 8% ;湖南龙山洛塔居群较低 ,为 10 .5 3 %。人工栽培居群中 ,美国密西根州和湖北武汉 2个居群的多态位点百分率也较低 ,仅分别为 10 .5 3 %和 8.77%。用POPGENE 1.31版软件进行数据处理后结果如下 :孑遗居群的平均Nei’s基因多样性为 0 .130 5 ,Shannon’s遗传多样性信息指数为 0 .192 1,水杉孑遗居群遗传距离与地理距离的相关系数r =0 .2 346 6 (P =73 .2 7% ) ,基因分化系数Gst=0 .10 82 ,表明居群间有一定分化。用UPGMA方法聚类可知 ,2个人工居群与湖北利川居群优先聚类。鉴于目前水杉孑遗居群生境人为破坏严重、遗传多样性较低和原生母树分布分散 ,建议在湖北利川小河和桂花野生水杉最适生境建立水杉遗传多样性保护点 ,将现有的 2 5 0多株原生母树分别采种育苗定植于保护点 ,以达到最大限度地保存现有水杉遗传多样性的目的。 展开更多
关键词 孑遗植物 水杉 RAPD 遗传多样性 保护
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新疆东准噶尔喀姆斯特晚古生代沉积记录:物源和沉积作用研究 被引量:12
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作者 张晓晖 李铁胜 +2 位作者 胡能高 杨家喜 许安东 《地质科学》 CAS CSCD 北大核心 2002年第1期13-26,共14页
东准噶尔喀姆斯特下泥盆统阿拉比也巴斯他乌组和下石炭统卡姆斯特组代表陆壳增生不同阶段的沉积响应。碎屑岩碎屑组成模式和地球化学分析结果表明阿拉比也巴斯他乌组形成于大洋—活动大陆过渡型构造环境 ,物源区主要为发育在过渡型地壳... 东准噶尔喀姆斯特下泥盆统阿拉比也巴斯他乌组和下石炭统卡姆斯特组代表陆壳增生不同阶段的沉积响应。碎屑岩碎屑组成模式和地球化学分析结果表明阿拉比也巴斯他乌组形成于大洋—活动大陆过渡型构造环境 ,物源区主要为发育在过渡型地壳之上的岩浆岛弧 ;卡姆斯特组形成于活动大陆型构造环境 ,物源区主要为大陆岛弧环境的切割岩浆弧。沉积相、相组合及生物生态等沉积特征显示两组的沉积环境分别为海底斜坡和海底扇中扇—外扇盆地平原。结合区域构造分析和地层对比研究 ,下泥盆统阿拉比也巴斯他乌组海底斜坡沉积是东准噶尔构造带早泥盆世弧后盆地沉积响应的主要记录 ,卡姆斯特组海底扇—海底平原沉积则主要记录了东准噶尔复合地体早石炭世晚期弧间残余海盆的沉积响应。 展开更多
关键词 物源 沉积作用 弧后盆地 残余海盆 晚古生代 东准噶尔 新疆 沉积环境 沉积记录
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黑龙江省东部残留盆地群早白垩世沉积相特征及演化 被引量:22
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作者 和钟铧 刘招君 +2 位作者 陈秀艳 何玉平 陈永成 《古地理学报》 CAS CSCD 2008年第2期151-158,共8页
黑龙江省东部残留盆地群早白垩世主要充填滴道组(裴德组)、城子河组(七虎林组和云山组)、穆棱组(珠山组)和东山组。沉积相以冲积扇相、(扇)三角洲相、湖泊相、海相等为主。沉积相研究结果表明,滴道组以冲积扇及(扇)三角洲粗碎屑沉积为主... 黑龙江省东部残留盆地群早白垩世主要充填滴道组(裴德组)、城子河组(七虎林组和云山组)、穆棱组(珠山组)和东山组。沉积相以冲积扇相、(扇)三角洲相、湖泊相、海相等为主。沉积相研究结果表明,滴道组以冲积扇及(扇)三角洲粗碎屑沉积为主,并伴随有火山岩分布,反映了盆地初始裂陷阶段的沉积环境特点;城子河组和穆棱组沉积时期,三江地区处于整体下沉阶段,现今残留的三江盆地、勃利盆地、鸡西盆地、虎林盆地、宁安盆地、鹤岗盆地和汤原断陷等为统一的近海拗陷盆地,张广才岭—小兴安岭及东三江和完达山地区是盆地主要物源供给区,平面上构成(扇)三角洲—滨浅湖—半深湖—湖底扇的沉积格局,并且伴随有多次海侵事件,海侵方向主要来自虎林盆地东部及绥滨坳陷北部;东山组沉积时期,盆地已明显萎缩,发育局限的(扇)三角洲—滨浅湖相沉积。 展开更多
关键词 黑龙江省东部 残留盆地群 早白垩世 近海拗陷盆地 沉积相
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