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1.
我国东部亚热带可分为过渡性亚热带和典型亚热带两部分.在偏北的过渡性亚热带内自然植被以含有常绿灌木层的落叶阔叶林为主,也有一些落叶阔叶一常绿阔叶混交林;冬麦和夏稻为一年两作制,常见梨、桃果园,而常绿果树如柑桔只见于局部小环境.在南部的典型亚热带内常绿栎林生长在酸性红黄壤上,而石灰岩土上则为落叶阔叶一常绿阔叶混交林.经常有双季稻和柑桔、茶、油茶、油桐的载培.亚热带的最南部主要为由茶科、樟科、金缕梅科、壳斗科等常绿阔叶树种所组成的杂木林,许多优良品质的柑桔类最适宜栽培.此外,要重视亚热带地区内许多湖泊的保护、开发和合理利用.  相似文献   

2.
本文对福建省建瓯万木林自然保护区常绿阔叶林的植物区系成分、群落外貌和结构做了初步分析。 调查植物计58科100属140种。植物种类以樟科、壳斗科、未兰科、山茶科、杜英科和山矾科为主。对种子植物属的地理成分统计表明,热带分布的地理成分占总属数的73%,温带分布的则占24.4%。而种的地理成分则以中国亚热带特有分布为主,占总种数的61.5%。 常绿阔叶林中高位芽植物占86.4%,以常绿成分为主。叶性则以中小型叶、革质、全缘单叶为主。群落结构较完整,可分林木、下木和草层等,藤本植物较发达,一些树木有小型板状根发育,为中亚热带较典型的常绿阔叶林。  相似文献   

3.
浙江省常绿阔叶林的基本特征(一)   总被引:5,自引:0,他引:5       下载免费PDF全文
文章根据对浙江省五个地点的常绿阔叶林的调查,对其种类成份、外貌和结构的特征,作了汇总分析。在本文中,首先讨论了常绿阔叶林所在的环境条件,说明我国常绿阔叶林是在东亚亚热带季风气候条件下孕育的一种特殊的植被类型。根据五个地点21个样地的统计,组成浙江常绿阔叶林的维管束植物共约428种,分属于105科,225属。在双子叶植物中壳斗科、樟科、山茶科的种类最多,它们均是构成林木层的基本成份。群落的优势种集中在少数的属中。如壳斗科的Castanopsis,Lithocarpus,Cyclobalanopsis,Quercus,山茶科的Camellia,Eurya,以及樟科的Machilus,Cinnamomum,Lindera,Litsea和杜鹃花科的Rhododendron以及蔷薇科的Photinia和Prunus等。同时还分析了常绿阔叶林区系的地理成份,分析表明它们与热带区系有着密切联系,尤其是与热带东南亚植物区系存在着较悠久的共同历史。温带、东亚分布类型的属的较高比例是我国东部亚热带常绿阔叶林的特征之一。中国亚热带特有种类的大量存在进一步表明了常绿阔叶林是我国亚热带地区的一种特有类型。  相似文献   

4.
浙江省常绿阔叶林的基本特征(一)   总被引:1,自引:1,他引:0  
文章根据对浙江省五个地点的常绿阔叶林的调查,对其种类成份、外貌和结构的特征,作了汇总分析。在本文中,首先讨论了常绿阔叶林所在的环境条件,说明我国常绿阔叶林是在东亚亚热带季风气候条件下孕育的一种特殊的植被类型。根据五个地点21个样地的统计,组成浙江常绿阔叶林的维管束植物共约428种,分属于105科,225属。在双子叶植物中壳斗科、樟科、山茶科的种类最多,它们均是构成林木层的基本成份。群落的优势种集中在少数的属中。如壳斗科的 Castanopsis,Lithocarpus,Cyclob-alanopsis,Quercus,山茶科的 Camellia,Eurya,以及樟科的 Machilus,Cinnamomum,Lindera,Litsea 和杜鹃花科的 Rhododendron 以及蔷薇科的 Photinia 和 Prunus 等。同时还分析了常绿阔叶林区系的地理成份,分析表明它们与热带区系有着密切联系,尤其是与热带东南亚植物区系存在着较悠久的共同历史。温带、东亚分布类型的属的较高比例是我国东部亚热带常绿阔叶林的特征之一。中国亚热带特有种类的大量存在进一步表明了常绿阔叶林是我国亚热带地区的一种特有类型。  相似文献   

5.
福建梅花山国家级自然保护区常绿阔叶林的群落学特征   总被引:1,自引:0,他引:1  
福建梅花山国家级自然保护区的常绿阔叶林是典型的中亚热带常绿阔叶林之一.9 600 m2样地的调查与分析表明:群落内共有维管束植物258种,其中种子植物228种,隶属于87科156属,植物的科属组成丰富.群落内区系地理成分复杂,热带与泛热带植物区系成分比例明显大于温带与泛温带区系成分,具热带亚热带性质.群落中,中小型革质、全缘、单叶、常绿、木本、高位芽植物是决定其外貌主要因素.群落成层现象明显,可分为2个乔木亚层、1~2个灌木亚层和草本层,层间植物较为丰富.通过不同区域常绿阔叶林的比较,无论区系组成与成分还是群落外貌和结构均体现了中亚热带南缘常绿阔叶林的特征.  相似文献   

6.
浙江天童及周边地区常绿阔叶林退化群落的植物区系分析   总被引:2,自引:0,他引:2  
浙江天童及周边地区的常绿阔叶林退化群落包括五个类型:常绿阔叶林退化前期群落、落叶阔叶林群落、针阔混交林群落、针叶林群落以及灌丛群落.通过对退化植被各群落类型的区系分析,得出了天童地区常绿阔叶林退化群落的区系组成特征,具体如下:(1)天童及周边地区退化植被的植物区系包括72科138属204种,其物种多样性低于常绿阔叶林的成熟群落;(2)本植物区系地理成分与常绿阔叶林成熟群落一致,表现了明显的亚热带植物区系性质,是热带向温带的过渡;(3)人类的干扰导致了各退化群落中国特有成分的下降;(4)各退化群落类型与常绿阔叶林成熟群落保持了较高水平的科、属和种的相似性.综上所述,天童及周边地区退化植被保持了亚热带常绿阔叶林的植物区系特征,从植物区系学的角度来看,具有恢复为地带性常绿阔叶林成熟群落的潜力.  相似文献   

7.
通过选择代表性地段,设置第三纪孑遗植物缺萼枫香群落样方,开展群落学调查,分析群落的物种组成、外貌及结构特征等.研究结果表明,群落中生长维管束植物177种,分属65科128属,科属组成较为复杂.在该地区,物种的区系地理成分丰富多样,以温带成分占优势,并含有较多古老属种.群落外貌由中、小型草质单叶的高位芽植物占优势,其中落叶成分所占比例相对较高.群落垂直结构分化明显,可以分为乔木层、亚乔木层、灌木层和草本层,树冠分布较为连续.天目山缺萼枫香群落是以落叶成分为主的、由中小型草质单叶的高位芽植物决定的常绿落叶阔叶混交林,具有古老性和残遗性.缺萼枫香林集中分布在中亚热带南部和中亚热带北部,种类组成表现较强的替代规律,随纬度升高落叶成分比例增加,常绿树种由适生冷凉气候的种类替代,常伴生有丰富的第三纪孑遗植物.应进一步研究缺萼枫香林群落的演替规律和演变历史,探讨枫香属植物的起源和进化以及冰期对第三纪森林的影响.  相似文献   

8.
通过对圩墩遗址出土古木15个树种的鉴定,确定五,六千年前圩墩存在过落叶-常绿阔叶混交林带。该林带是温带针,阔叶混交林带与亚热带常绿阔叶林带之间的过渡区,属温暖,湿润的亚热带植被类型。落叶阔叶树有壳斗科的麻栋和槲栎类,金缕梅科的枫香,漆树科的黄连木及豆的黄檀等树种。常绿阔叶树有茶科的荷木,豆科的红豆树及木犀科的蜡树等树种。  相似文献   

9.
浙江省常绿阔叶林的基本特征(二)   总被引:4,自引:0,他引:4       下载免费PDF全文
浙江省常绿阔叶林的基本特征,除在本文(一)中所述外,还包括以下诸方面:三、浙江省常绿阔叶林的外貌特征常绿阔叶林首先就是从其终年常绿和具有浑圆的树冠而区别与其它类型。群落外貌主要是由群落的生活型组成、叶的性质以及周期性所决定的。(一)生活型群落的生活型组成是决定群落外貌的主要因素,它反映了群落的特殊生境以及群落内部可能产生的竞争。对前述五个地区所有样地的全部植物种类,按 Raunkiaer 生活型分类标准进行统计(图1)的结果表明,其中以高位芽植物占明显的优势(64.1%,如加上藤本植物的12.6%,可达76.7%),其次为地  相似文献   

10.
南京地处亚热带向暖温带的过渡区,长期以来,在自然区划和植被区划中都被确认为属于北亚热带常绿阔叶与落叶阔叶混交林地带。这个地带的确定,与秦岭——淮河线被确定为亚热带常绿阔叶林带和暖温带落叶阔叶林带的分界线有密切的关系。在中国植被区划中南京位于常绿阔叶林带的北部边缘,是常绿阔叶林向落叶阔叶林的过渡地区,植被类型属常绿阔叶与落叶阔叶混交林类型。究竟在南京有没有常绿阔叶与落叶阔叶混交林群落存在?南京  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 Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
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   

15.
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   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
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   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
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   

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