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vegetation     
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  植被
     Research into Several Key Problems Existing in Vegetation Construction in Loess Plateau
     黄土高原植被建设中若干关键问题的研究
短句来源
     Research on the Remote Sensing Means of Monitoring Grassland Vegetation Change
     草地植被变化遥感监测方法研究
短句来源
     Vegetation Background and Succession Rule in Northwest China
     西北地区植被背景值及演替规律研究
短句来源
     Study on Dynamic Change of Vegetation and Desertification in Oasis Based upon RS and GIS Techniques
     基于RS和GIS的绿洲植被与荒漠化动态研究
短句来源
     Based on FVC Data to Analyse the Spatiotemporal Variation of Vegetation Cover in China Western Arid Land 1982~2000
     基于FVC指数对1982~2000年中国西部干旱区植被覆盖时空变化特征分析
短句来源
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  植物
     A Preliminary Study of the Soils and Vegetation of Darjeeling Area,Southeastern Himalaya,India
     印度喜马拉亚山东南麓大吉岭区之土壤与植物
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     The Research into the Law of Change about the Efflux of K~+ of Vegetation under the Influence of SO_2
     SO_2影响下植物钾离子(K~+)渗出量变化规律的研究
短句来源
     Catalytic Potentiometric Determination of Trace Manganese in Vegetation with lonSelective Electrode.
     离子选择性电极催化电位法测定植物中的微量锰
短句来源
     Plant Interspecific Correlation and a Vegetation Numerical Classification of Mount Baihua in Beijing
     北京百花山植物种间相关性和植被数量分类
短句来源
     VEGETATION MONITORING FOR ECOLOGICAL ENVIRONMENT AT SHAWAN DESERT AREAS
     沙湾荒漠区生态环境的植物监测
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  赘生物
     104<4mm(92 86%)closed spontaneously 3 30 months later,8>4mm(7 14%)complicated with infectious endocarditis(vegetation),obliged to restore.
     其中104例(92.86%)RSD<4mm,在3~30个月内RS自然愈合,8例(7.14%)RSD>4mm者因RS太大合并感染性心内膜炎(赘生物)等不能自行愈合,需要再次手术修补。
短句来源
     Morphologic Observation and Detection of Human Papillomavirus Antigen in 43 Cases Perineum Vegetation
     43例会阴部赘生物的形态观察及人乳头状瘤病毒抗原的检测
短句来源
     There were 7 mitral,9 aortic,and 1 tricuspid valve vegetations,mean vegetation size was 0.8cm (extremes: 0.3-1.6cm).
     平均赘生物大小 0 .8cm (范围 0 .3~ 1.6cm)。
短句来源
     Vegetation was found in 13 cases(56.52%) by ultrasound echocardiography.
     超声心动图发现赘生物13例(56.52%)。
短句来源
     Vegetation was found in 29 (64.4%) patients by TTE .
     29例(64.4%)患儿经胸超声心动图检查发现赘生物,平均直径为11.1mm。
短句来源
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  增殖体
     Diagnostic value of direct digital radiography(DDR) with dual energy subtracti on in children′ s snoring disease caused by tonsil and adenoid vegetation
     DDR双能量减影在扁桃体、腺样增殖体所致儿童鼾症诊断中的临床应用
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      vegetation
    Based on the basic principles of the micrometeorology of atmospheric boundary layers and vegetation canopy, a numerical model of the interaction between forest ecosystems and atmospheric boundary layers was developed.
          
    Increased vegetation cover and change in farming techniques were suggested to prevent and control wind erosion of sand and soil.
          
    Under artificial plantations, the vegetation layer (including roots) had a mean carbon density of 111.3 t/hm2, the litter layer a density of 5.1 t/hm2, and the soil layer a density of 64.9 t/hm2.
          
    The ratios of carbon density among vegetation, litter, and soil pools were 39.6:1.8:58.6 for artificial forests and 57.4:2.7:39.9 for natural forests.
          
    The carbon densities of the vegetation and litter layers increased exponentially with forest age.
          
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    A.The Soils Since the goological formation of this mountainous area is quite uniform,a vertical distribution of soils is obviously observed. At the top of the mountain with an elevation of 8,500 feet,the podzolic soil is found. The process of podzolization is clearly shown by the translocation of clays,organic matter, and active aluminum from an upper to lower layer.The gray brown podzolic soil is distributed in areas ranging from 7,000 to 8,500 feet in elevation.It is developed under forest and has a...

    A.The Soils Since the goological formation of this mountainous area is quite uniform,a vertical distribution of soils is obviously observed. At the top of the mountain with an elevation of 8,500 feet,the podzolic soil is found. The process of podzolization is clearly shown by the translocation of clays,organic matter, and active aluminum from an upper to lower layer.The gray brown podzolic soil is distributed in areas ranging from 7,000 to 8,500 feet in elevation.It is developed under forest and has a surface covering of leaf litter and a surface soil with high content of organic matter.In places at an elevatin from 3,900 to 7,000 feet the yellow podzolic soil is dominant.At an elevation below 3,000 foot the red podzolic soil and the sketetal soil are fonnd. The analytical data of the soils of this area may be summarized as follows: 1.pH values of the soils:In the whole area,since the parent rock (gneiss) is poor in basic constituents,soils are all acid in reaction.The pH of the different horizons of the soils ranges from 4.0 to 5.5.The A_0 and A_1 horizons are usually less acid than B horizon,the A and B horizons are much more acid than the parent rock.This shows the leaching process of the soils under such a humid atmosphere. 2.Organic Matter of the soils:The organic matter content of the soils in this area is greatlg influenced by the kind of the vegetation cover.At an elevation of 8,500 feet, the soil developed under forest has 38.92% of organic matter in the A_1,while that under grass has only 11.08% of organic matter in the corresponding horizon.However as the vegetation cover is constant,the dopth of the A_1 and its organic matter content are evidently affected by the elevation.At an elevation of 3,000 feet,the A_1 horizon of the red podzolic soil is only 1 cm.in depth,and it has 3.37% of organic matter.At an elevation of 8,500 feet,howerver,the A_1 horizon of the podzolic soil is 7 cm.in depth, and it has 11.08% of organic matter.In addition,deposition of organic matter in the B horizon is clearly found in the podzolic soil,but it has not been seen in soils found at lower elevation. 3.Active aluminum of the soils:All the soils in this area are high in active aluminum. They contain from 20 to 16 p.p.m.of active aluminum.The content of active aluminum in the different horizons of the same profile has a very close relationship with the pH values of the corresponding horizon.The less acid the reaction the smaller is the amount of acitve aluminum.The active aluminum of the soil is usually higher in amount than that of the parent rock from which the soil is derived. 4.Available calcium magnesium,and potassium of the soils:All the soils are general- ly low in available calcium,magnesium,and potassium.The comparatively high content of these elements in the A horizon is derived from the leaves of the vegetation which are grown on that soil. 5.Available phosphorus of the soils:All the soils of this area are low in available phosphorus. 6.Available nitrate:All soils in this area are very low in nitrate. B.The Vegetation 1.The plants growing on soils of this area are most calcifuge species which are acid- loving (Vaughan and Wishe,1937).As far as the chemical analysis of the soil is concer- ned,those species may be assumed as not only acid-loving,buy also active aluminum- loving (Hutchinson,1943). 2.The distribution of the calcifuge plants In this area is apparently affected by the local climate in terms of elevation.Some of them (temperate plants) are confined to high elevation,others(tropical plants) being limited to low elevation,Two groups of the plants may be given as follows.Many of them are of the same species as those found in southwestern China (Hou,1944). (a) Plants mainly ocurring in areas at elevations from 7,000 to 8,500 foot (temperate plants): Pteridophyta: Destaedtia Scabra (Wall.) Moore Diranopteris linearis Under. Hicrioptris glauea Under. Hymenophyllum crispatum Wall. Hymenophyllum exsertum Wall. Lidsaya cultrata Sw. Lycopodium clavatum L. Plagiogyria pyphylla (Kunze) Mett. Pteridium aquilinum Wightianum Trym Pteris aspericaulis Wall. Flowering Plants: Castanopsis tribuloides A.DC. Lindera pulcherrima Bth. Osbeckia crinata Bth. Rhododendron arboreum Sm. Rhododendron grande Wight Pieris formosana D.Don Vaccinium refersceda HK. Vaccinium serrasum Wight (b) Plants mainly ocurring in areas at elevation from 1,000 to 3,000 feet (tropical plants): Pteridophyta: Adiantum philippense L. Blechnum orientale L. Aglaoorpha coronaus Copel Lycopodium cernum L. Nephrolepsis cordifolia Presl Tectaria spp. Polypodium ucidum Roxb. Flowering plants: Oxyspora paniculate DC. Themeda arundinacea Ridl.

    1945年10月中旬,作者留印三月另一周,曾作三次野外调查,计包括印缅边区、恒河平原及喜马拉雅山东南麓等三区,茲先将大吉岭区调查结果,草成此文。调查区域大吉岭位于喜马拉雅山东南麓,在我国西藏边境,全区是山地,海拔自1000到9000尺不等,主为酸性的片麻岩地层,在拔海6500尺地点,年平均气温为56.3℉.,年雨量为122寸。土壤灰壤——灰棕壤组合:在拔海8500尺左右的山顶,灰壤见于草地上,而灰棕壤则发育在森林之下。灰棕壤——灰化黄壤组合:在拔海7000—8000尺地带,森林下仍是灰棕壤,而草地上则为灰化黄壤。灰化黄壤——粗骨土组合:在拔海1000—3000尺地带,片麻岩生成灰化红壤,酸性砂岩生成砾质土。全区土壤特征可归纳如下: (1)土壤 pH 值:全区因土壤母质为酸性片麻岩,各类土壤剖面亦为酸性反应;pH 值约自4.0至5.5。A_1层之 pH 值恒较 B 层为大,而土壤剖面内之 A 层及 B 层均较母岩之酸度为高。 (2)土壤有机质:从土壤有机质分析结果观之,显示植物种类对于土壤有机质之含量高低,有密切的关系,在拔海8500尺之地带,发育于森林下的灰棕壤,表土含有机质38.92%,而同处草类和蕨类植物...

    1945年10月中旬,作者留印三月另一周,曾作三次野外调查,计包括印缅边区、恒河平原及喜马拉雅山东南麓等三区,茲先将大吉岭区调查结果,草成此文。调查区域大吉岭位于喜马拉雅山东南麓,在我国西藏边境,全区是山地,海拔自1000到9000尺不等,主为酸性的片麻岩地层,在拔海6500尺地点,年平均气温为56.3℉.,年雨量为122寸。土壤灰壤——灰棕壤组合:在拔海8500尺左右的山顶,灰壤见于草地上,而灰棕壤则发育在森林之下。灰棕壤——灰化黄壤组合:在拔海7000—8000尺地带,森林下仍是灰棕壤,而草地上则为灰化黄壤。灰化黄壤——粗骨土组合:在拔海1000—3000尺地带,片麻岩生成灰化红壤,酸性砂岩生成砾质土。全区土壤特征可归纳如下: (1)土壤 pH 值:全区因土壤母质为酸性片麻岩,各类土壤剖面亦为酸性反应;pH 值约自4.0至5.5。A_1层之 pH 值恒较 B 层为大,而土壤剖面内之 A 层及 B 层均较母岩之酸度为高。 (2)土壤有机质:从土壤有机质分析结果观之,显示植物种类对于土壤有机质之含量高低,有密切的关系,在拔海8500尺之地带,发育于森林下的灰棕壤,表土含有机质38.92%,而同处草类和蕨类植物发育下的灰壤的表土,仅含有机质11.08%,但在相同的植物环境下,拔海高度或局部气候,也是支配土壤有机质含量的重要因素,例如在拔海3000尺地带,长有草类的灰化红壤,仅有极薄之有机质层,该层有机质含量为3.37%,而在拔海8500尺地带,长有草类的灰壤,则有较厚层有机质,其含量为11.08%。 (3)可溶性铝质:全区土壤含有高量可溶性铝,大约自20至160 p.p.m.,其含量与 pH 值高低相关,土壤 pH 值愈酸,可溶性铝含量就愈高。 (4)可溶性钙镁及钾质:全区土壤之可溶性钙,镁及钾等之含量均较低,但就同一土壤剖面而言,富于有机质的 A。或 A_1层的钙镁和钾质,常较 B 层为高,此点显示此等成份是来自植物遗体,亦即指示土壤中有机质与肥力之关系。 (5)全区土壤有效磷含量均甚低。 (6)全区土壤硝酸态氮之含量均极低,并有下淋现象。植物本文所论植物,仅以作者所采集而经各专家鉴定为限,其中以蕨类植物为主。本区的土壤都是酸性反应,所见的植物是以嫌钙性者为主,这些嫌钙性植物与拔海高度的关系很显著,兹将常见的植物种类,叙述如下: (一)主分布于拔海7000—8500尺地带的植物: 蕨类植物 Dennstaedtia scabra(Wall.)Moore Dicranopteris linearis Under. Hicriopteris glauca Under. Hymenophyllum crispatum Wall. Hymenophyllum exsertum Wall. Lindsaya cultrata Sw. Lycopodium clavatum L. Plagiogyria pycniphylla(Kunze)Mett. Pteridium aquilinum Wightianum Trym. Pteris aspericaulis Wall.种子植物 Castanopsis tribuloides A.DC. Lindera pulcherrima Bth. Osbeckia crinata Bth. Rhododendron arboreum Sm. Rhododendron grande Wight Pieris formosana D.Don Vaccinium referesceda HK. Vaccinium Serrasm Wight(二)主分布于1000—3000尺地带的植物: 蕨类植物Adiantum philippense L.Blechnum orientale L.Aglaomorpha coron(?)us copelLycopodium cernuum L.Nephrolepsis cordifolia PresslTectaria spp.Polypodium lucidum Roxb.种子植物Oxysoira paniculata DC.Themedra arundinacea Ridl.

    The natural vegetation of Shantung Province, in the north temperate zone, is of the aestisilvae type. As the natural conditions vary in different parts of this province, the vegetation may be divided into the following four regions: 1. Alluvial plain of the Yellow River: This region is located at the northern part of this province. The saline soil is unfavorable for the growth of most plants. The following plants are characteristic: Tamarax chinensis, Apocynum venetum, Suaeda salsa, S. glauca, Artemisin...

    The natural vegetation of Shantung Province, in the north temperate zone, is of the aestisilvae type. As the natural conditions vary in different parts of this province, the vegetation may be divided into the following four regions: 1. Alluvial plain of the Yellow River: This region is located at the northern part of this province. The saline soil is unfavorable for the growth of most plants. The following plants are characteristic: Tamarax chinensis, Apocynum venetum, Suaeda salsa, S. glauca, Artemisin capillaris, Aeluropus littoralis, Miscanthus sinensis, Phragmites karka, Carex sp. etc.. 2.Western Shantung plain: This region is located at the western part of the province. Most of the land is under cultivation and the soil is rich in calcium. There is no forest. The common trees are Populus tomentosa, P. alba P. davidiana, Ulmus spp. etc., and the herbaceous plants are Cynodon dactilon, Digitaria sanguinalis, Echinochloa colonum, Imperata cylindrica, Chenopodium album, Convolvulus chinensis,Xanthium japonicum, Crypi saculeata, Scirpus maritimus etc.. Plants which grow in the lake district largely belong to Phragmites communis, Scirpus maritimus, Zizania latifolia, Euryale ferox, Trapa bispinosa etc.. 3.Central South hilly region: This region has mostly been transformed into farms for a long time. On the hilly region there are still some remnant forests. The important trees are Pinus tabulaeformis, Biota orientalis. Quercus acutissima, Q. variabilis, Betula chinensis, Tilia mongolica etc.. On account of calcareous soil in this region, Biota orientalis is found most extensively. Gramineae leads all other herbaceous plants in abundance. The following species such as Arundinella amomala, Bothriochloa ischaemum, Setaria viridis, Pennisitum flaccidum etc. have a wide distribution. 4. Shantung Peninsula: The common native plants in this region are Pinus densiflora, Quercus dentata, Q. acutissima, Robinia pseudoacacia, Acer mono etc.. Pious densiflora is a native plant which grows all over the hilly region. Herbaceous plants are mostly Thymus serpyllum, Setaria viridis, S. lutescens etc.. Due to the oceanic climate with higher precipitation and humidity, plants enjoy a more vigorous growth than those in other regions. There develops a richer flora, some even with warm temperate elements.

    山东省之位置属于温带,植物分布为落葉闊葉林區,但在鲁中南及膠東區爲丘陵地带,落葉闊葉樹乃與針葉樹成混交林澑鶕∧谥匀粭l件,可将植物分布情况列為四區: 1.黃河冲積平原區:位於北部,為黄河三角州地帶,土壤含鹽分甚重,不宜於植物之生長。樹木只有檉柳、茶棵子等;草本以黄鬚菜、鹼蓬、茵陳蒿,獐毛、芒、蘆葦、黑三稜草等最為砇姟?2.魯西平原區:為西部之黄河冲積平原,多為農田,土壤含鈣甚多。區內無森林,常見之樹木有毛白楊、白楊、山楊、榆等?荼居泄费栏ⅠR唐、芒稷、白茅、藜、旋花、蒼耳、隱花草、荆三稜等。湖泊區域多蘆葦、荆三稜、蒲姜草、芡、菱等。3.魯中南區:為丘陵地區,平緩部分已闢為農田。山區有殘留森林,主要樹種為油松、侧柏、麻櫟、栓皮櫟、堅樺、椴等;土壤石灰質,側柏之繁盛為共特點。草本以禾本科為最多,常見的如野古草、白羊草、狗尾草、白草等,此外如細葉莎草、雞眼草、蚊子草等亦為砇姟?4.膠東區:在山東半島部份,主要樹種為赤松、洋槐、麻櫟、五角楓等,赤松自山麓至山上均有分佈,且為其鄉土,此乃本區之特徵;草本以蚊子草、狗尾草、金狗尾草為最多。在海灘地上少有高大樹木,常見樹種如洋槐、旱柳等均為栽培者,野生木本植物有酸棗...

    山东省之位置属于温带,植物分布为落葉闊葉林區,但在鲁中南及膠東區爲丘陵地带,落葉闊葉樹乃與針葉樹成混交林澑鶕∧谥匀粭l件,可将植物分布情况列為四區: 1.黃河冲積平原區:位於北部,為黄河三角州地帶,土壤含鹽分甚重,不宜於植物之生長。樹木只有檉柳、茶棵子等;草本以黄鬚菜、鹼蓬、茵陳蒿,獐毛、芒、蘆葦、黑三稜草等最為砇姟?2.魯西平原區:為西部之黄河冲積平原,多為農田,土壤含鈣甚多。區內無森林,常見之樹木有毛白楊、白楊、山楊、榆等?荼居泄费栏ⅠR唐、芒稷、白茅、藜、旋花、蒼耳、隱花草、荆三稜等。湖泊區域多蘆葦、荆三稜、蒲姜草、芡、菱等。3.魯中南區:為丘陵地區,平緩部分已闢為農田。山區有殘留森林,主要樹種為油松、侧柏、麻櫟、栓皮櫟、堅樺、椴等;土壤石灰質,側柏之繁盛為共特點。草本以禾本科為最多,常見的如野古草、白羊草、狗尾草、白草等,此外如細葉莎草、雞眼草、蚊子草等亦為砇姟?4.膠東區:在山東半島部份,主要樹種為赤松、洋槐、麻櫟、五角楓等,赤松自山麓至山上均有分佈,且為其鄉土,此乃本區之特徵;草本以蚊子草、狗尾草、金狗尾草為最多。在海灘地上少有高大樹木,常見樹種如洋槐、旱柳等均為栽培者,野生木本植物有酸棗、舖地胡枝子等;草本植物多蘆葦、狗尾草等。此區氣候由於受篞笳{節,雨量與溼度亦較高,故植物生長較其他三區繁盛,種類亦較多,亞熱带植物之分布亦多於他處,尤以海邊低地為甚。在自然地理上,秦嶺、淮河一線是中國南北氣候和土壤的重要分界線,也是植物的重要分界線。但是從山東的植物分布上,可以知道這條線並不能絕然的将植物分為南北二部分,因為山東仍是一个過渡的地帶,許多南方植物在魯南及膠東沿海都有分佈,如黄檀、山胡椒、烏桖、厚朴、王蘭、木犀、黄楊、谜葉樹等多种。在另一方面,北方植物分佈至山東為其最南界限者如糠椴、遼珍珠梅、遼磯松、榛等;而赤松、蒙古機、蒙椴等則南达苏北之雲台山。由此可加,山東之植物分佈上,仍在秦嶺、淮河一線之範圍内,如以淮河來作為植物之南北分界線,则并不能完全符合實際情况,尤以膠東沿海低地,南方植物種類繁多,可與淮河流域相此。因此,此一分界线之東端似有北移之必要。山東植物之分佈乃由環境条件综合影響之結果,但在不同地区,各種因素之作用並不一致,由於地形、土壤、温度和水分等之区别而使植物分布不同。本文所举植物種类和分布地點都是從各項资料所得到,作者将其分為四區,並初步提出了這種分区的理由和形成不同分布的原因。但限於材料的不够完全和水平的淺薄,因此本文的內容很不充實, 只能作为令後进一步研究山东植物地理的基础,希望大家提出补充和指出不正确的地方,而使这一项工作能够顺利的完成。

    The city of Lanehow lies in the central part of China in latitude approximate 36°03′north, longitude 103°57'east, at elevation 1,508.53 M. Kowlanshan, the area surveyed, being one of the many loess plateau hills surrounding Lanchow, situates on the southeastern suburb of the city. Physiographically, the area is a part of the dissected loess plateau with an altitude of 1,508-2100 M. Owing to the influences of the geographical condition and high elevation, the climate of this area is of continental climatic type....

    The city of Lanehow lies in the central part of China in latitude approximate 36°03′north, longitude 103°57'east, at elevation 1,508.53 M. Kowlanshan, the area surveyed, being one of the many loess plateau hills surrounding Lanchow, situates on the southeastern suburb of the city. Physiographically, the area is a part of the dissected loess plateau with an altitude of 1,508-2100 M. Owing to the influences of the geographical condition and high elevation, the climate of this area is of continental climatic type. The mean annual precipitation is 338.6mm. with 61.1% of it falling in June, July and August, annual mean temperature, 6.9℃., relative humidity, 58%, annual total evaporation, 3,571mm. and annual mean wind velocity 5.8m/sec. The upper portion of the hill is entirely covered with a thick layer of loess and underneath lies the red earth of the tertiary period. As a result of that, soils in the area surveyed, which has been developed from the loess, is high in calcium content. It belongs to the chestnut soil type with a PH value between 7.6 and 8.1. The vegetation of this area shows the following ecological characteristics: 1) The specific composition of the plant is rather scanty with about. 124 speeies belonging to 93 genera and 41 families; 2) The vegetation bears a simple physiognomy. No natural growth arbor been found in the whole area during the period of investigation, though a few species of cultivated trees are found and the vegetation is mainly composed of semi-frutexes and herbages; 3) Most of the essential species distributing here express distinct xeromorphic structures and many of them are typical components of the vegetation of the steppe and semi-dessect, such as Caragana spp., Hololachne soongarica Ehrenb., Artemisia spp., Chrysanthemum neofruticulosum Ledeb., Stipa spp. Achnatherum splendens Ohwi. and so on. Four plant associations are found in this area. Three of them distribute on the Dorthern slope and one on the southern slope of the hill. They are described as follow: Ⅰ. Chenupodium album+Artemisia annua+Elymus dasystachys Association. The distribution of this association is limited to the erosion valleys situating on the piedmont belt of the northern slope at an elevation between 1, 510 and 1, 560 M., where the edaphic condition is marked by high soil moisture content. The climatic features are of low light intencity with short duration of daily sunshine, high relative humidity and low wind velocity. Three hygrophilous and shade-loving species are the main constituents of this association. They are chenopodium album L., Artemisia annua L., and Elymus dasystachys Trin. Other herbaceous plants are Chenopodium glaucum L.. Sonchus aler- aceus L., Xanthium strumarium L., Polygonum amphibium L., P. aviculare L. etc. A few shrubs are present in the association. They are Lycium chinensis Mill., Lonicera heteroloba Batal. and Lonicera ferdinandi Fr. Ⅱ. Artemisia pectinata Association. The Artemisia pectinata Association occurs on the piedmont belt of the northern slope at an elevation varying from 1510 to 1580 M. It occupies the open slope with gradients under 15°. The climatic conditions, in speaking of the northern slope, are rather high in temperature, strong light intencity, low relative humidity and low wind velocity. The projective total cover-degree is about 50% and Artemisia pectinata Pall. appears to be the dominant species in the association. Besides, there are species of thermophilous and heliophilous plants such as Salsola kali L., S. arachnoides‘Moq’. Kung, Cymbaria mongolica Maxim., Artemisia capillaris Thumb., Aster altaicus willd., chrysanthemum neofruticulosum Ledeb., which are frequently scattered among the dominant plants. Plants growing in this association, are all below 10 cm. in height. They give an appearence of open association. Ⅲ. Chrysanthemum neofruticulosum+Artemisia sacrorum var. latiloba—Polytrichum sp. Association. This association, being the largest one in the surveyed area, appears on the northern slope, where it occupies the space ranging from altitude 1,580M. to the top of the hill,2,100M, above the sea level. Soil is of chestnut soil type with a PH value of 8. 0—8. 1.The soil moisture content varies between 6.0 and 7.4%(layer above 60 cm.). In vertical structure, the association consists of two strata. They are described below: Stratum Ⅰ: This stratum includes all shrubs, semi-frutexes and herbages which are taller than 10 cm. in height. Among the plants found in this stratum, chrysanthemum neofruticulosum Ledeb. and Artemisia sacrorum var. latiloba Ledeb. are dominant species and Stipa Bungeana Trin. is the subdominant one. Other species one may frequently meet with are Allium subangulatum Rag., Saussurea nigrescens Maxim., Peganumharmala L., Astragalus dahuricus Dc., Potentilla multifida L., Linum perenne L., Car-agana frutex K. Koch. etc. They spread widely in almost all over the association. Stratum Ⅱ: This stratum is composed of those species less than 10 cm. in height, forming the ground flora of the association. Polytrichum sp. and Lichens are the essential plants in the stratum. One may occasionlly find species of Plantago Lessingii and Gentiana squarrosa Ledeb. growing among those main constituents. The underground stratification of the association has also been studied during the time of surveying. IV. Stipa Bungeana+Aster altaicus+Chrysanthemum neofruticulosum Association. This association distributes on the entire southern slope except the portions tilled for agriculture purposes. The striking local ecological conditions of this association are strong light intensity with long duration of daily sunshine, high temperature, low relative humidity and extremely low in soil moisture content which ranges between 2. 7 and 4. 0% (the layer above 60cm.). On account of the severe destruction of natural vegetation by man and cattle in the past years, the degree of soil erosion is serious throughout the slope where the association locates. The PH value of the soils is 7.4-76. The polydominant plants in this association are Stipa Bungeana Trin., Aster altaicus Willd. and Chrysanthemum neofruticulosum Ledeb. They are quite adaptable to the drought condition of the environment and distribute widely in the association. Besides, other xerophilous or drought resistant plants are frequently met, such as Hololachne soongarica Ehrenb., Linum perenne L., Astranalus dahuricus Dc., Peganum harmala L., Artemisia sacrorum var. latiloba Ledeb., Artemisia capillaris Thumb., Incarvillea Iutea Bur.&Franch., Kochia scoparia Schred. etc. They dispersely grow in the association. In addition to the frequent species mentioned above, Salsola ruthenica Iljin. and S. arachnoides‘Moq’. Kung form seperately micro-associations lying scatterly on the slope. No ground flora stratum may be found and the association shows no above ground stratification. The projective total cover-degree of this association is only about 25-30%. Owing to the difference in the aspects of the northern and sourthern slopes, the climatic and edaphic conditions vary remarkable. Therefore, the vegetation of the surveyed area shows distinctions in distribution, floristic composition, physiognomy, structure, condition in growth and development of plants in the association of different slopes. Taking the floristic composition for example, the following species are entirely absent in the association of the northern slope, yet they are main components on the southern one: Pappophorum brachystachyum Taub. et Spach, Thermopsis lanceolata R. Br., Caragana spinosa Dc., Stellera chamaejasme L., Hololachne soongarica Ehrenb., Nitraria schoberi L., Pennisetum flaccidum Griseb. Differences in elevation also induce striking changes in climatic and edaphic con-ditions especially in aspects of air temperature, relative humidity and soil moisture content. All these gives great influence to the alterations either in quantity or in quality of each species distributing along the northern slope of the area. Following the seasonal change, the physiognomy of the associations expresses sucession of seasonal aspect. Vernal, aestival and autumnal aspects have been observed and recorded.

    兰州位于我国的中心,约占北纬36度03分,东经103度57分,拔海1508.53米。皋兰山是兰州四周环山中的最高峰,位居兰州市东南郊。在地形上,皋兰山属于分割黄土高原山岭的一部分,拔海高度约为2100米。由于地理位置及海拔的影响,兰州的气候属大陆性气候类型。年平均温度为6.9℃,年平均雨量为338.6毫米,而61.61%集中在6、7、8、三个月,全年各月平均相对湿度为58%,年蒸发量则达3,571毫米,风力为5.8米/秒。皋兰山山岭的顶部均为厚层的黄土所掩盖,其下则为第三纪红土层。因此,调查区的土壤,全由黄土母质发育而来,含多量钙质,属栗钙土类,PH值为7.6—8.1。调查区的植被,有如下的生志特点:(1)植物种属比较贫乏:全区植物只有41科,93属,124种;(2)群落外貌单纯:调查区内缺乏自然生长的乔木,植被主要由半灌木与草本植物所构成,属干燥草原区的灌木草本群落型;(3)植物具明显旱生形态:群落主要成分,很多是干燥草原区的代表种属,如锦鸡儿属、蒿属、菊属的小黄菊(Chrysanthemum neofruticulosum Ledeb.)、羽茅属、芨芨草等。它们都具有各种适应干旱环境的形态特征。调查区植物...

    兰州位于我国的中心,约占北纬36度03分,东经103度57分,拔海1508.53米。皋兰山是兰州四周环山中的最高峰,位居兰州市东南郊。在地形上,皋兰山属于分割黄土高原山岭的一部分,拔海高度约为2100米。由于地理位置及海拔的影响,兰州的气候属大陆性气候类型。年平均温度为6.9℃,年平均雨量为338.6毫米,而61.61%集中在6、7、8、三个月,全年各月平均相对湿度为58%,年蒸发量则达3,571毫米,风力为5.8米/秒。皋兰山山岭的顶部均为厚层的黄土所掩盖,其下则为第三纪红土层。因此,调查区的土壤,全由黄土母质发育而来,含多量钙质,属栗钙土类,PH值为7.6—8.1。调查区的植被,有如下的生志特点:(1)植物种属比较贫乏:全区植物只有41科,93属,124种;(2)群落外貌单纯:调查区内缺乏自然生长的乔木,植被主要由半灌木与草本植物所构成,属干燥草原区的灌木草本群落型;(3)植物具明显旱生形态:群落主要成分,很多是干燥草原区的代表种属,如锦鸡儿属、蒿属、菊属的小黄菊(Chrysanthemum neofruticulosum Ledeb.)、羽茅属、芨芨草等。它们都具有各种适应干旱环境的形态特征。调查区植物群落,可区分为下列的四个群丛: 1.白药+黄花蒿+厚穗滨草群丛(Chenopodium album+Artemisia annus+Elymus dasystachys Association) 本群丛分布于皋兰山山麓的侵蚀沟谷内,约占海拔1510至1560米的地段。所在地气候与土壤特点是光线弱、日照时间短、风力小、大气相对湿度大与土壤潮湿。群丛优势种有白藜、黄花蒿和厚穂滨草三种喜湿耐阴植物。此外,伴生有灰绿藜、苦苣菜、苍耳、两栖蓼、扁蓄等草本植物。灌木则可见枸杞(Lycuim chinensis Mill)、紫金银花(Lonicera heteroloba Batal.)、裴氏金银花(L.ferdinandi.Fr.)三种。 2.篦叶蒿群丛(Artemisia pectinata Association) 这一群丛占据皋兰山北坡山麓海拔1510—1580米,坡度在15°以下的开旷地段。其环境条件,在北坡来说,主要表现于阳光充沛,温度高,大气相对湿度低与土壤干燥。群丛总夏盖度约为50%,而以篦叶蒿最占优势。常见植物有钾猪毛菜、灰蓬(Salsola arachnoides‘moq’Kung)、蒙古芯芭(Cymbaria mongolica Maxim.)、茵陈蒿、阿尔泰紫菀、小黄菊等喜光喜温种类。 3.小黄菊+供蒿-藓群丛(Chrysanthemum neofruticulosum+Artemisia sacrorum var latiloba-Polytrichum sp. Association) 本群丛包括皋兰山北坡自海拔1580米以上一直至山顶(海拔2100米)的全部地段,为调查区内分布面积最广的群丛。其生态环境是阳光弱、日照时间短、蒸发量小、气温低;土镶为栗钙土,PH值在8.0—8.1左右,土壤风干含水量为5.2—5.6%。群丛在垂直结构上,可分为两层:第一层包括高度在10厘米以上的灌木、半灌木与草本植物,而以小黄菊和供蒿最占优势。本氏羽茅则为本属中的亚优势种。常见植物尚有野葱、青木香(Saussurea nigrescens Maxim.)、骆驼蓬、达乌里紫云英,多裂委陵菜、宿根亚麻、木锦鸡儿(Caragana frutex K. Koch.)等。第二层为地被层,主要由藓类和地衣所组成。此外,偶尔出现细叶车前(Plantago Lessingii)与鳞叶龙胆(Gentiana squarrosa Ledeb.)铺地生长。群丛总复盖度约为67%。 4.本氏羽茅+阿尔泰紫菀+小黄菊群丛(Stipa Bungeana+Aster altaicus+Chrysanthemum neofruticulosum Association) 这一群丛占皋兰山南坡除农田以外的全部地区。其气候与土壤条件,可归纳为下:日晒强烈、日照时间长、气温高;人为对自然植被破坏强烈,表土冲刷现象异常严重。土壤水分含量甚低,仅占风干重的1.88—3.41%,pH值为7.4—7.6。本氏羽茅、阿尔泰紫菀与小黄菊为群丛中的主要种类。它们对于干旱的环境均具有强大的适应力。其他常见植物有红砂、宿根亚麻、达乌里紫云英、骆驼蓬、供蒿、茵陈蒿、黄角蒿(Incarvillea lutea Bur.&Franch.)地肤等抗旱或耐旱种类。苏联猪毛菜(Salsola rutheniea Iljin)和灰蓬,常各成单纯小群丛,出现于山坡间。本群丛中缺地被层,无地上成层现象。群丛总复盖度仅为25—30%。由于南北坡取向不同所引起气候与土壤因子的变化,调查区植物群落,在分布、结构、外貌、种类成分及生长发育状况上,也随着发生很大的差异。海拔高度的改变,对气温、相对湿度,土温及土壤水分状况的影晌,也明显地反映在群落中各个种间的数量比例关系上。随着季节的更换,群落中的种类成分,表现出比较显著的季相演替关系。作者等曾作北坡群丛春、夏和秋三季季相的观察与纪录。

     
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