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1.
大连市5个海岛野生维管束植物多样性研究   总被引:3,自引:0,他引:3  
大连地处辽东半岛南端,三面环海,岛礁众多.通过对大连5个具有典型代表意义的海岛实地调查,查明了5个岛屿的野生维管束植物的种类,并分析了其物种多样性特点.结果表明,5个海岛共有野生维管束植物81科260属439种,其中蕨类9科9属16种,裸子植物2科2属3种,被子植物70科249属420种;5个海岛的野生维管束植物组成复杂,植物成分以温带性质为主,有一定的热带亲缘;经计算比较,5个海岛间野生维管束植物相似程度较低,推测小尺度下植物相似性程度与岛屿面积、离岸距离和人为干扰程度有一定联系.另外,5个海岛的物种数量与岛屿面积符合Mac Athur RH等提出的岛屿生物地理学理论,物种数量随着岛屿面积的增加而增加.  相似文献   

2.
为进一步掌握四川百里峡省级自然保护区维管束植物区系分布和特征,文中主要采用野外实地调查结合查阅文献资料的方法,系统整理出保护区维管束植物名录并进行分析.结果表明,区系中有维管束植物156科685属1 447种,其种数占全国、全省的比例分别为4.98%和15.64%,说明物种多样性较为丰富.蕨类植物的组成以少种科为主,占比为39.47%;种子植物在科的组成上,寡种科占比40.60%,是该保护区的优势科.植物区系地理成分复杂,其中温带分布有明显优势,共有342属775种,其次为泛热带分布,体现了该区域内植被的地带性.  相似文献   

3.
本文从药用植物的种类、科属构成和生活型等方面对仙人洞国家级自然保护区药用维管束植物多样性进行研究.结果表明:保护区内共有药用维管束植物97科260属407种,分别占仙人洞自然保护区保护区维管束植物资源总科、属、种的89.81%、65.16%、48.98%.本文分析了仙人洞自然保护区药用植物资源多样性形成的原因,并对药用维管束植物的保护开发提出了具体意见.  相似文献   

4.
四川百里峡省级自然保护区植物资源调查研究   总被引:1,自引:0,他引:1  
为进一步掌握四川百里峡省级自然保护区植物资源的现状,对保护区植物资源进行调查,结果表明:自然保护区共有野生维管植物150科,682属,1 429种.其中蕨类植物22科,44属,74种;裸子植物8科,17属,24种;被子植物120科,625属,1 319种.维管植物科数占四川省的64.66%,全国的41.21%;属数占四川省的42.32%,全国的20.20%;种数占四川省的15.32%,全国的4.88%.保护区有国家Ⅰ级保护植物7种,国家Ⅱ级保护植物13种,此外还有现被列为世界级极危植物—崖柏.种子植物区系共有15个类型和18个变型.植物区系温带性质明显,热带成分也占一定的比例,具有温带向热带过渡的特征.植物区系具有一定的古老性.保护区植被划分为3个植被型组,8个植被型,24个群系.  相似文献   

5.
缙云山自然保护区种子植物区系研究   总被引:6,自引:0,他引:6  
缙云山自然保护区拥有长江中上游保存较为完好的亚热带常绿阔叶林,其种子植物区系具有以下特征:区内有种子植物166科803属1 565种,其中野生种子植物达139科550属1 023种;科、属组成的优势现象明显,含10种以上的优势科有23科,所含属、种数分别占总属数和总种数的56.36%和62.85%,含5种以上的19个优势属所含的种数占总种数的15.74%,这些科、属在该区系组成中占明显的主导地位;区系地理成分复杂,热带成分优势明显,体现了由热带性质向温带性质的过渡性特征.缙云山在种子植物物种数量及分布区类型上都较为丰富,植物区系起源古老,并就该保护区植物资源的保护提出了建议.  相似文献   

6.
通过野外调查、采集标本并结合文献资料,完成闽浙交界交溪流域规划区植物名录,并对该地区维管束植物区系成分进行分析.结果表明:交溪流域规划区共有维管束植物218科,818属,1 887种;在科级水平上泛热带分布类型最多,有93科,占总科数的42.66%;属级水平上也是泛热带分布类型最多,有191属,占总属数的23.35%;中国特有分布科2科,特有分布属18属.说明该地区植物物种丰富,植物区系以泛热带特征为主.  相似文献   

7.
通过野外样地调查,结合文献资料和标本鉴定,对戴云山自然保护区植物区系特征进行了分析。结果表明,保护区内植物多样性丰富,共有野生种子植物1 753种,隶属于181科741属;种子植物科的组成以中科、小科为主,种数集中在中等科,优势科不是很明显;种子植物属的组成以极小属为主,种数集中在小属;种子植物科、属的地理区系成分复杂,以热带、亚热带成分占优势,兼具部分温带性质;属于中国特有种有18属20种。  相似文献   

8.
江西铜钹山自然保护区药用植物资源研究   总被引:1,自引:0,他引:1  
通过野外线路考察、标本采集、实物拍摄、物种鉴定及民间访问调查,结果显示铜钹山自然保护区药用植物资源丰富,共计有药用维管植物183科618属1 284种。其中蕨类植物27科51属87种;裸子植物8科13属13种;被子植物148科554属1 184种;珍稀濒危保护植物14科27属30种。对保护区药用植物资源现状进行了分析研究,提出了药用植物资源保护建议,为药用植物资源保护与合理开发利用提供科学依据。  相似文献   

9.
随着北京地区人口的增多,人类活动范围越来越大,野生维管束植物的分布也逐渐发生了变化.依据北京地区实地野外调查数据及相关文献,对15个调查单元的野生维管束植物进行统计分析.结果表明:北京地区野生维管植物共计1505种,国家重点保护野生维管束植物3种,北京市保护野生维管束植物98种,受危胁野生维管束植物36种,中国特有野生维管束植物199种,且主要分布于门头沟区、密云县、延庆县、怀柔区、海淀区、房山区、昌平区.本文的研究对北京市各县(区)进行生物多样性评价及生物多样性保护等提供了最新最基础的数据.  相似文献   

10.
濒危植物狭果秤锤树所在群落的区系特征   总被引:2,自引:0,他引:2  
调查重新发现了濒危植物狭果秤锤树(Sinojackia rehderiana)在赣北的分布,采用植被调查样方法研究了狭果秤锤树所在群落维管植物的区系特征.结果表明,该区系组成复杂,物种密度相对较高.在1 600 m2样方中,有维管束植物57科74属79种,其中蕨类植物6科10属10种,双子叶植物43科53属58种,单子叶植物8科11属11种.物种密度约达5种.(100 m2)-1.分布区类型多样,热带区系成分占优势.科、属、种地理成分以热带分布成分为主,温带成分占有一定比例;反映了该群落的热带-亚热带区系性质.热带成分与温带成分在本区交汇,体现出中亚热带向北亚热带植物区系过渡的特征.该群落分布面积小且邻近村落,具有明显的生态脆弱性,禁伐是维持该森林群落稳定性的关键措施.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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