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1.
本文收集了国内曼陀罗属(Datura L.) 11个不同的生态型，在光学显微镜和扫描电镜下，进行了花粉粒形态的比较观察。该属花粉粒均为球形或稍扁，具3孔沟型。花粉粒外壁表面的纹饰可作为分属、分组、分种的依据之一。可分为三个类型，与植物形态分类基本一 致，即：具皱波-细网状纹饰(曼陀罗组); 具网状条纹或条纹，条脊表面有细颗粒或粗糙(洋金花组); 具条纹，条脊表面有蚕体状环纹及细颗粒(木本曼陀罗组)。种以下的变种或栽培变种，花粉粒的形态特征不足以作为分类的依据。 相似文献
2.
全面阐述桦木科 6属 36种植物叶表皮和花粉的形态及系统学价值 ;首次揭示中国特有属———虎榛子属胚胎发育的全过程 ;化石植物有重要发现 ,发现了美国怀俄明古新世一个化石新属———Cranea和Palaeocarpinus属的两个化石新种 ,是迄今为止所发现的桦木科榛亚科最早的化石纪录 ;利用形态学资料、rbcL基因序列、ITS序列分别对桦木科及外类群进行分支分析 ,并根据化石植物提供的证据 ,将三者结合分析 ,重建了桦木科的系统发育 ,建立了桦木科的新分类系统 相似文献
3.
一般来讲,进化学派承认分支学派对系统学的研究作出了有意义的贡献,如应用分支分析方法重建系统发育,应用共有衍征确定分类群之间的分支关系以及应用外类群方法来判断性状的极性等,都对系统学的方法有所改进。但分支学派的致命缺点是拒绝接受并系类群。我们属于进化学派,认为并系类群是可以接受的。例如,根据分子资料分析,Zabelia属可以包括于Abelia属内。Zabelia属不但在花粉上和Abelia属不同,可能由于它占有了新的生态位,获得了新的特征,如叶柄基部膨大两两联合,并宿存以保护腋芽。有理由认为它们应独立成属,并不由于Zabelia属从Abelia属分出而使后者成为一个并系类群而把它们合并。分支学派的一些学者认为生物名称作为交流的工具和生物信息储存系统应有明晰的、唯一的和稳定的特性。但具等级的林奈命名系统并不具有这些特性来命名分支和种。最后,PhyloCode被提出。PhyloCode对分支的命名方法有3种,即分支结点定义、分支基干定义和衍征定义。我们认为林奈命名系统作为传媒系统在生物学界的应用已近250年,若要废弃它而采用PhyloCode,必然会在命名方面引起一片混乱。但我们并不是说PhyloCode的拥护者所提出的建议一无是处,我们建议他们宜继续进行研究。由于应用生物学种概念于植物界产生了许多问题,因此多为植物系统学家所抛弃。分支学派的兴起,推动了系统发育种概念的提出。该概念基于3个特征,即自征、区别特征和基本排它,因此分别命名为自征种概念、特征种概念和谱系种概念。事实上,目前大多数植物系统学家仍然应用着形态–地理学种概念,但我们在划分种时,必须有尽可能多的资料,特别是要将传粉、繁育系统、分子系统学资料和形态学资料结合起来。 相似文献
4.
对被子植物起源研究中的几种观点进行了讨论。(1)由于被子植物存在着一组共同的性状,它们不可能是从不同祖先起源的,而是有着共同的祖先。被子植物是一个单源起源的类群。现存被子植物分类系统是依据包括形态学(广义)、分子系统学、古植物学和植物地理学等的综合性状建立的,只能表示出现存类群的亲缘关系并且追溯到它们最近的祖先。人们现在还不可能建立一个包括全部已绝灭的类群和现代生存类群的谱系发生系统。因此,现存被子植物分类系统只能看作是“亲缘”系统。(2)分析了用于推测被子植物起源时间的分子、化石和地理分布证据。我们认为,要确定被子植物起源时间,植物化石是一类重要证据,但化石只能说是植物本身可保存部分和当时当地所提供的化石条件的综合反映,它们不可能就是植物类群或种的起源时间。人们还必须考虑到化石本身的演化历史。应用分子钟也是一种手段,但误差比较大。如果我们除了利用上述两种资料之外,根据植物类群的现代分布格局及其形成,把植物的演化同地球的历史和板块运动联系起来,以推断它们起源的时间,这无疑会增加其可信度。通过对56个种子植物不同演化水平的重要科属地理分布的研究结果,我们曾提出被子植物的起源时间可能要追溯到早侏罗世,甚至晚三叠世。(3)分析了基于分子证据所提出的被子植物基部类群——ANITA成员(包括无油樟科Amborellaceae、睡莲科Nymphaeaceae、八角目Illiciales、早落瓣科Trimeniaceae、木兰藤科Austrobaileyaceae)的性质,讨论了ANITA成员在现代几个被子植物分类系统中的系统位置的不同观点,评价了它们的形态学(广义)性状。指出ANITA的成员由于包含大量的祖征,是属于原始的类群。但由于它们的共有衍征很少,如花粉球形,说明它们在被子植物演化早期就分道扬镳了,沿着不同的传代线分化。因此ANITA是一个源于不同传代线的复合群。 相似文献
5.
领春木的染色体数目及配子体的发育 总被引：1，自引：0，他引：1
本文报道了领春木属的一个国产种Euptelea pleiospermum Hook.f.et Thoms的染色体数目，n=14，2n=28。描述了它的胚珠结构，大小孢子的发育及胚囊的类型。 相似文献
6.
The classical and numerical taxonomy, palynology and the geographical dis-
tribution of the Genus Schizopepon are dealt with in the present paper. Having comme-
nted on various opinions regarding the systematic position of the genus, the present au-
thors consider that C. Jeffrey’s treatment of Schizopepon as a new and monogeneric tri-
be, Schizopeponeae, should be supported.
The gross morphological characters in the genus are assessed from the taxonomic
point of view. Some characters, such as stamens with an elongated connective or not,
different insertions of ovules and various forms of ovaries and fruits, may be used for
distinguishing subgenera.
The pollen grains of all the species were observed under light microscope (LM) and
scanning electron microscope (SEM). The results show that a strong differentiation
has taken place in the pollen of the genus, and in consequence it may be regarded as an
important basis for dividing subgenera and species. Especially it should be pointed out
that degrees of development of colpi and positions of ora are positively correlated with
the external characters used for distinguishing subgenera.
According to the morphological and palynological characters, the genus Schizopepon
may be divided into three subgenera and eight species: 1. Subgenus Schizopepon: 5 spe-
cies, S. bryoniaefolius Maxim., S. monoicus A. M. Lu et Z. Y. Zhang, S. dioicus Cogn.,
S. longipes Gagnep. and S. macranthus Hand.-Mazz.; 2. Subgenus Rhynchocarpos A. M.
Lu et Z. Y. Zhang: 1 species, S. bomiensis A. M. Lu et Z. Y. Zhang; 3. Subgenus Neoschi-
zopepon A. M. Lu et Z. Y. Zhang: 2 species, S. bicirrhosus (C. B. Clarke) C. Jeffrey
and S. xizangensis A. M. Lu et Z. Y. Zhang.
The 8 OTU’s including all the species of this genus and 31 characters, of which 16 are morphological characters and 15 palynological characters, were used in the numerical taxonomic treatment. After standardization of characters, the correlation and distance matrices were computed. The correlation matrices are made to test the various clustering methods. At last, the UPGMA clustering method was selected and its result
is shown in the form of phenogram. The result of numerical analysis is similar to that of the classical classification.
Schizopepon Maxim. is a genus of East Asia-Himalayan distribution. China has all 8 species and 2 varieties, of which 6 species are endemic. Based on the statistics of spedies number, the distribution centre of the genus is considered to be in the Hengduan Mountains (Yangtze-Mekong-Salwin water divides) and the adjacent areas of the southwest China. 相似文献
7.
桦本科植物的起源和早期演化 总被引：2，自引：0，他引：2
根据植物类群演化的时空统一观点，利用古植物学、地理分布和系统发育三个方面的研究结果，讨论了桦木科植物的起源和早期演化，认为：最早的桦木科植物生活在晚白垩纪桑托期，起源于中国中部地区，起源之后，一方面较缓慢地向欧洲散布，并在古新世到达欧洲；另一方面向中国东北地区散布，并迅速扩散到北极地区，通过白令陆桥在白垩纪最晚期到达了北美。 相似文献
8.
The current problems being studied by different authors of the evolution of
angiosperms are reviewed in general. An analysis of the arguments on principles and
methodology of the system of plant classification have been made. We support the
views put forward by the phylogenetic school and hold that phylogeny should be
taken as the guiding principles upon which the classificational system of angiosperms
should be built and as the ultimate aim of taxonomy. We disagree with the views of
the phenetic school. The course of evolution is a unity of the process of the origin
and the development in its history and the process of dispersal of angiopserms on
earth. The contradiction of variability and heredity is the driving force in the evolu-
tion of angiopserms, nay, of all organisms.
In the methodology we suggest that comparative analysis should ge hand in hand
with the experimental synthesis. In essence, the classification based on overall simi-
larities or most numbers of attributes to determine the relationships between various
groups of angi osperms is the deductive inference of formal logic. For the elucidation
of the laws of the origin and development of angiosperms the method of analysis and
synthesis of the dialectical logic should be adopted.
The progress of studies achieved in the origin and angiopserms of particularly
monocotyledons has been summarized, and the common points and discrepancies of the
authors have also been pointed out. The tendency of further development in the stud-
ies of the origin of angiosperms has been estimated. All branches of botany have
acumulated a large amount of data. Since 1960 some significant works have been
done, especially on the origin and early evolution of angiosperms, which has been being
the central problem of more intensive study challenging all botanist of different dis-
ciplines today.
The review is concluded with a proposal that in order to do further research on
the origin and early evolution of angiopserms, all branches of botany must cooperate,
and main attention should be paid to the important groups which may play a key rolein the development of plant life on earth. 相似文献
9.
在吸取各学派对被子植物原始类群界定的基础上，根据八纲系统，提出被子植物原始类群有60科的新见解，并以分子系统学提出的狭义的基部类群32科为对比，进行了植物地理学研究。以科为性状，以Takhtajan 划分的世界植物区系的“区”为OTU，UPGMA分析显示：(1)东亚区确是一个十分特殊的区，它既与北美东、西部(北美大西洋区、马德雷区)有密切关系，但更接近印度支那区；(2)环太平洋的4个地区集中了较多的原始被子植物的科，它们是东亚地区，北美东部和西部地区，部分热带亚洲、澳大利亚东部和西南太平洋岛屿地区，中、南美热带地区。这种分布格局显然和被子植物起源地与扩散以及太平洋的形成历史有关。 相似文献
10.