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1.
随着市场日益分化、随着科学技术的迅速发展，传统的广告形式不再像过去那样吸引消费者的眼球。本文对时下广受注目的网络这种品牌宣传形式进行深入的分析，并就如何利用网络成功达到品牌宣传的目的提出了独到的、系统的建议。 相似文献
2.
本文首次记载了对分布于峨眉山的凤仙花属Impatiens 12种植物的种子表面显微结构的观察，
并分析了种子表面形态在该属种水平上的分类价值及可能的系统学意义。种皮表层细胞特化、排列方
式、隆起状态、种脊上近合点端的突起、种子末端附属物的有无及其形态等性状被视为凤仙花属种子表
面的主要特征。依据这些性状12种凤仙花种子形态分为两种类型：1．种子表面光滑，无明显大、小细胞
分化。如白花凤仙I．wilsoni可能具3沟花粉凤仙花的种子形态的特点。2．表面粗糙，有明显大、小细
胞的分化及不同程度的细胞隆起，并呈现出多种特异形态．这代表了以一年生草本，4沟花粉为特点的
凤仙花种子形态特征。种子特征与植物体习性、花形态及花粉形态相关，在一定程度上反映了属内类群的分化，因而在凤仙花科、属的分类和系统研究中是不可忽视的性状。 相似文献
3.
杜宝贵 《科学学与科学技术管理》2001,22(5):17-23
通过对科学发展进程的考察以及对科学分化的种类的描述，归纳出了科学分化基本特点、分化机制以及分化结果，揭示了传统意义上的科学分化涵义的局限性，扩大了科学分化的基本内涵和外延。 相似文献
4.
5.
造血细胞工程的基础研究与临床应用 总被引：1，自引：0，他引：1
造血系统是体内高度活跃和高度新陈代谢的系统,造血干细胞具有自
我更新能力和高度增殖以及多向分化的潜能,利用这些性能可以在体外大量扩增造血细胞,
并可定向诱导其分化成熟,还可以对其功能进行激活或调控,以及靶向性转染目的基因等,
最终满足基础研究和临床应用的需要,本文将简要介绍造血细胞工程的主要研究内容及其相
关的研究进展。 相似文献
6.
7.
马金双 《中国科学院研究生院学报》1989,27(5):321-364
本文通过对东亚和南亚马兜铃属的研究，修改了马兜铃属的分类系统，补充论证了演化趋势；并
在分析该属地理分布的基础上提出马兜铃属分布与分化的第二个中心——中国的横断山区。 本文确
认2亚属、7组、4系、68种和1变种，其中有3新组、2新种及13个新异名。 相似文献
8.
9.
通过对冬、春青稞、冬、青小麦代表品种的分蘖成穗，幼穗分化，籽粒灌浆规律和产量因于构成特点连续四年的系统观察、比较，分析明确了冬青稞的增产机理。证实：（１）苗期持续时间工，生长缓慢极有利于分蘖发生成穗。（２）幼穗分货物别单棱期比春青稞长１４０和６０多天，从而使三联小穗基分化数猛增。典定了粒多大穗的基础，这是冬稞增产的内在原因。 相似文献
10.
11.
马尾树科的形态及分类系统位置的讨论 总被引：1，自引：0，他引：1
张芝玉 《中国科学院研究生院学报》1981,19(2):168-178
The present paper is devoted to a study of the basic morphological and anatomical
characteristics of the endemic family Rhoipteleaceae from China. The fundamental
pattern of the morphological and anatomical characteristics of the Rhoipteleaceae is
similar to those of the Juglandaceae in wood anatomy, resinous peltate scales, apetaly,
bicarpellate pistils, one-seeded fruits and exalbuminous seeds. Whereas Rhoipteleaceae
has stipules; perfect flowers with superior 2-loculed ovaries, anatropous ovules and two
integuments; vessel elements of the secondary xylem with the scalariform perforation,
and 2–8 (18) pores on the oblique plate being observable; vascular rays heterocellular
and tricolporate pollen. The above characteristics–at least most of them, agree
pretty well with those depicted by Manning in his “Pre-Juglandaceae”. It is quite
possible that the Juglandaceae is derived from “Pre-Juglandaceae”by way of the
Rhoipteleaceae, as the morphological and anatomical features as indicated above tend to
show that the Rhoipteleaceae is more primitive than Juglandaceae.
The Rhoipteleaceae was previously considered as related to the Betulaceae or
Ulmaceae, a view, which the present study does not prove to be acceptable. Both Takh-
tajan (1969) and Cronquist (1968) pointed out that the Juglandales, Urticales, Myrica-
les, Fagales are all direct derivatives from the Hamamelidales. However, since the
Rhoipteleaceae is simillar to the Betulaceae in wood anatomy and pollen, it seems that
there too could have certain relationships between the Rhoipteleaceae and the Betula-ceae in the course of evolution. 相似文献
12.
论胡桃科植物的地理分布 总被引：1，自引：0，他引：1
路安民 《中国科学院研究生院学报》1982,20(3):257-274
The present paper aims to discuss the geog raphical distribution of the Juglandaceae
on the basis of unity of the phylogeny and the process of dispersal in the plants.
The paper is divided into the following three parts:
1. The systematic positions and the distribution patterns of nine living genera in
the family Juglandaceae (namely, Engelhardia, Oreomunnea, Alfaroa, Pterocarya, Cyclo-
carya, Juglans, Carya, Annamocarya and Platycarya) are briefly discussed. The evolu-
tional relationships between the different genera of the Juglandaceae are elucidated. The
fossil distribution and the geological date of the plant groups are reviewed. Through
the analysis for the geographical distribution of the Juglandaceous genera, the distribu-
tion patterns may be divided as follows:
A. The tropical distribution pattern
a. The genera of tropical Asia distribution: Engelhardia, Annamocarya.
b. The genera of tropical Central America distribution: Oreomunnea, Alfaroa.
B. The temperate distribution pattern
c. The genus of disjunct distribution between Western Asia and Eastern Asia:
Pterocarya.
d. The genus of disjunct distribution between Eurasia and America: Juglans.
e. The genus of disjunct distribution between Eastern Asia and North America:
Carya.
f. The genera whose distribution is confined to Eastern Asia: Cyclocarya, Platy-
carya.
2. The distribution of species
According to Takhtajan’s view point of phytochoria, the number of species in every
region are counted. It has shown clearily that the Eastern Asian Region and the Coti-
nental South-east Asian Region are most abundant in number of genera and species. Of
the 71 living species, 53 are regional endemic elements, namely 74.6% of the total species.
The author is of the opinion that most endemic species in Eurasia are of old endemic
nature and in America of new endimic nature. There are now 7 genera and 28 species
in China, whose south-western and central parts are most abundant in species, with Pro-
vince Yunnan being richest in genera and species.
3. Discussions of the distribution patterns of the Juglandaceae
A. The centre of floristic region
B. The centre of floristic regions is determined by the following two principles: a.
A large number of species concentrate in a district, namely the centre of the majority;
b. Species of a district can reflect the main stages of the systematic evolution of the
Juglandaceae, namely the centre of diversity. It has shown clearly that the southern
part of Eastern Asian region and the northern part of Continental South-east Asian
Region (i.c. Southern China and Northern Indo-China) are the main distribution centre
of the Juglandaceae, while the southern part of Sonora Region and Caribbean Region
(i.c. South-western U.S.A., Mexico and Central America) are the secondary distribution
centre.
As far as fossil records goes, it has shown that in Tertiary period the Juglanda-
ceae were widely distributed in northern Eurasia and North America, growing not only
in Europe and the Caucasus but also as far as in Greenland and Alaska. It may be
considered that the Juglandaceae might be originated from Laurasia. According to
the analysis of distribution pattern for living primitive genus, for example, Engelhar-
dia, South-western China and Northern Indo-China may be the birthplace of the most
primitive Juglandaceous plants. It also can be seen that the primitive genera and the
primitive sections of every genus in the Juglandaceae have mostly distributed in the
tropics or subtropics. At the same time, according to the analysis of morphological cha-
racters, such as naked buds in the primitive taxa of this family, it is considered that
this character has relationship with the living conditions of their ancestors. All the
evidence seems to show that the Juglandaceae are of forest origin in the tropical moun-
tains having seasonal drying period.
B. The time of the origin
The geological times of fossil records are analyzed. It is concluded that the origin
of the Juglandaceae dates back at least as early as the Cretaceous period.
C. The routes of despersal
After the emergence of the Juglandaceous plant on earth, it had first developed and
dispersed in Southern China and Indo-China. Under conditions of the stable tempera-
ture and humidity in North Hemisphere during the period of its origin and development,
the Juglandaceous plants had rapidly developed and distributed in Eurasia and dis-
persed to North America by two routes: Europe-Greenland-North America route and
Asia-Bering Land-bridge-North America route. From Central America it later reached
South America.
D. The formaation of the modern distribution pattern and reasons for this forma-
tion.
According to the fossil records, the formation of two disjunct areas was not due to
the origin of synchronous development, nor to the parallel evolution in the two con-
tinents of Eurasia and America, nor can it be interpreted as due to result of transmis-
sive function. The modern distribution pattern has developed as a result of the tectonic
movement and of the climatic change after the Tertiary period. Because of the con-
tinental drift, the Eurasian Continent was separated from the North American Conti-
nent, it had formed a disjunction between Eurasia and North America. Especially, under
the glaciation during the Late Tertiary and Quaternary Periods, the continents in Eu-
rasia and North America were covered by ice sheet with the exception of “plant refuges”, most plants in the area were destroyed, but the southern part of Eastern Asia
remained practically intact and most of the plants including the Juglandaceae were
preserved from destruction by ice and thence became a main centre of survival in the
North Hemisphere, likewise, there is another centre of survival in the same latitude in
North America and Central America.
E. Finally, the probable evolutionary relationships of the genera of the Juglanda-ceae is presented by the dendrogram in the text. 相似文献
13.
金缕梅类科的系统发育分析 总被引：1，自引：0，他引：1
本文运用分支分类的方法对金缕梅类进行了系统发育的分析。金缕梅类作为单元发生群包括下
列19科：昆栏树科、水青树科、连香树科、领春木科、杜仲科、金缕梅科、悬铃木科、交让木科、假槲树科、双颊果科、折扇叶科、黄杨科、西蒙得木科、木麻黄科、山毛榉科、桦木科、杨梅科、马尾树科和胡桃科。木兰科在分析中被选择作为外群类。在对大量性状进行评估之后，选择了32对性状作为建立数据矩阵的基本资料。性状极化主要以外类群比较、化石证据和通行的形态演化规律为依据。首次引入了不合谐数的概念来检测性状极化结果的正确程度，并对少数不合谐数较大的性状的极性进行了调整。采用最大同步法、最小平行进化法和综合分析法进行运算，按照最简约的原则，选出演化长度最短的谱系分支图，作为本文讨论的基础，并在此基础上，探讨了金缕梅类科的系统关系。 相似文献
14.
本文根据植物类群的系统发育和地理分布相统一的原理,讨论了“低等”金缕梅类植物的起
源和散布。 “低等”金缕梅类植物(Endress1989a的概念)包括下列7科：昆栏树科、水青树科、连香
树科、折扇叶科、领春木科、悬铃木科和金缕梅科。 该类群共有13种分布区类型,东亚区的南部和
印度支那区的北部是它的现代分布中心;根据化石证据及原始类群和外类群的分布分析,以上地区最
有可能是这类植物的起源地。 “低等”金缕梅类植物起源的时间至少可追溯到早白垩纪巴列姆期,较可
靠的化石证据说明悬铃木类植物在早白垩纪阿尔必晚期出现,而昆栏树科、水青树科、连香树科和金
缕梅科植物的出现均不晚于晚白垩纪。 最后,从环境变迁和生物演化两个方面探讨了“低等”金缕梅类植物现代分布格局的形成原因。 相似文献
15.
方振富 《中国科学院研究生院学报》1987,25(4):307-313
1. The distribution of Salix species among the continents. There are about
526 species of Salix in the world, most of which are distributed in the Northern Hemisphere
with only a few species in the Southern Hemisphere. In Asia, there are about 375 species, mak-
ing up 71.29 percent of the total in the world, including 328 endemics; in Europe, about 114
species, 21.67 percent with 73 endemics; in North America, about 91 species, 17.3 percent with
71 endemics; in Africa, about 8 species, 1.5 percent, with 6 endemics. Only one species occurs
in South America. Asia, Europe and North America have 8 species in common (excluding 4
cultivated species). There are 34 common species between Asia and Europe, 14 both between
Europe and North America and between Asia and North America, 2 between Asia and Africa.
Acording to the Continental Drift Theory, the natural circumstances which promoted speciation
and protected newly originated and old species were created by the orogenic movement of the
Himalayas in the middle and late Tertiary. Besides, the air temperature was a little higher in
Asia than in Europe and North America (except its west part) and the dominant glaciers were
mountainous in Asia during the glacial epoch in the Quaternary Period. Then willows of Eu-
rope moved southwards to Asia. During the interglacial period they moved in opposite direc-
tion. Such a to-and-fro willow migration between Asia and Europe and between and North
America occurred so often that it resulted in the diversity of willow species in Asia. Those
species of willows common among the continents belong to the Arctic flora.
2. The multistaminal willows are of the primitive group in Salix. Asia has 28 species of
multistaminal willows, but Europe has only one which is also found in Asia. These 28 species
are divided into two groups, “northern type” and “southern type”, according to morphology of
the ovary. The boundary between the two forms in distribution is at 40°N. The multistami-
nal willows from south Asia, Africa and South America are very similar to each other and
may have mutually communicated between these continents in the Middle or Late Cretaceous
Period. The southern type willows in south Asia are similar to the North American multista-
minal willows but a few species. The Asian southern type willows spreaded all over the conti-
nents of Europe, Asia and North America through the communication between them before the
Quaternany Period. Nevertheless, it is possible that the willows growing in North America
immigranted through the middle America from South America. The Asian northern type mul-
tistaminal willows may have originated during the ice period.
The multistaminal willows are more closed to populars in features of sexual organs. They
are more primitive than the willows with 1-3 stamens and the most primitive ones in the ge-
nus.
3. The center of origin and development of willows Based on the above discussion it is re-
asonable to say that the region between 20°-40°N in East Asia is the center of the origin and
differentiation of multistaminal willows. It covers Southern and Southwestern China and nor-
thern Indo-China Pennisula. 相似文献
16.
本文根据叶绿体基因rbcL的核苷酸序列证据讨论了单型科——马尾树科的系统关系。数据矩
阵中包括了马尾树科及其它“高等”金缕梅类各科,并分别利用Cunoniaceae科的bauera属,“低等”金缕梅类植物连香树属和枫香树属作为外类群进行分支分析。两种分析的结果是一致的。在rbcL基因树上,马尾树属和被用于分析的胡桃科各属紧密地结合在一起,支持马尾树科和胡桃科有非常近的亲缘关系。 相似文献
17.
本文根据植物类群的系统发育和地理分布统一的原理，讨论了獐牙菜属植物的起源、散布和分
布区的形成。獐牙菜属包括11组16系154种，间断分布在亚洲、欧洲、北美洲和非洲。中国西南部-
喜马拉雅地区汇集了大多数种类、不同演化水平的类群以及形形色色的特有类群，成为该属的多样化
中心和多度中心。该属的原始类群和外类群也集中分布在中国西南山地，极有可能是该属的起源地。该
属的分布区类型中出现了各式的间断分布，根据有该属植物分布的大陆间及大陆与岛屿间分离和连接
的时间推测，该属的起源时间至少不会晚于晚白垩纪，也许更早，可追溯到中白垩纪。通过分类群间亲
缘关系和现代分布分析，显示出该属植物从起源地向周围和一定方向散布，形成了三个主要散布途径。在散布过程中植物本身也发生演化和就地特化，形成新的类群。 相似文献
18.
马兜铃科的地理分布及其系统 总被引：1，自引：0，他引：1
马金双 《中国科学院研究生院学报》1990,28(5):345-355
马兜铃科基本是一个热带科。 东亚的横断山至华南一带是其原始分布与分化中心，热带美洲是其次生分布与分化中心。科的形态演化趋势是花被由分化的双被到不分化的单被，由分离到合生，由杯状到管状；雄蕊由多数到少数，由分离到与雌蕊结合成为合蕊柱；于房由半下位到完全下位；果实由蓇葖状蒴果到蒴果。马兜铃科分2亚科4族6属。 相似文献
19.
本文报道浙江产菝葜属smilax 7个种的染色体数目和核型。S．nipponica有两种核型，2n＝
26和2n=32，均为3B型，但后一种细胞型的雄株的第一对染色体大小不等，可能为性染色体；S.
riparia 2n=30，属3B型；S．siebodii n＝16；S. china有两个染色体数目，2n＝96 和n＝15；
S. davidiana 2n=32，属3B型，对减数分裂MI的观察发现n＝16；S．glabra 2n=32，亦属3B
型：S. nervo-marginata var．liukiuensis 2n=32，属3C型。讨论了种间在核型上的差异、属的基数、
核型演化趋势和性染色体等问题。 相似文献
20.
藤山柳属Clematoclethra(猕猴桃科)是中国特有属之一。本文作者研究了该属植物的
外部形态，统计了473张标本，结合地理分布，得出本属是一个单种属，并且是一个多型种的结
论。此种分为4个亚种。这与中国植物志的作者将本属分为20种和4变种不同。 本文作者
虽强调标本室分类是生物系统学研究的基础，是必不可少的一步，但这种分类，其方法上必须
根据大量标本，从研究性状变异开始，然后确定各分类群的划分和等级，最后才根据植物命名
法规的模式方法，给予它们正确名称。作者还根据本属的姊妹群猕猴桃属和它们的外类群水 东哥属的地理分布，推断本属是一个新特有属。 相似文献