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本文报道了东亚植物区系中双子叶植物9个种的体细胞染色体新计数，其中6个是属的新计数，并对这些资料与有关的科或属在系统学和进化上的意义作了讨论。 相似文献
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一、引言 石蒜属Lycoris Herb.全世界约有20多种,其中已做过细胞染色体计数者计有17种。本文继红蓝石蒜Lycoris haywardii Traub和换锦花L.sprengeri Comes exBaker以及长简石蒜L.longituba Y.Hsu et Fan,玫瑰红石蒜L.rosea Traub etMoldenke,石蒜L.radiata(L′Her.)Herb.和矮小石蒜L.radiata var.pumila Grey(以上均待发表)之后,对安徽石蒜L.anhweiensis Y.Hsu et Fan和中国石蒜L.chinensis Traub的染色体进行计数和核型的描述和分析,旨在为今后探讨石蒜属的核型进化和种系发生提供必要的资料。 相似文献
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一、什么是植物区系植物区系,是植物学中一常用的名词,是指居住在一定的地理范围内的植物种的总体。组成一植物区系的各分类学、单位称为区系植物。植物区系和植物群落具有不同的概念。当我们提到象针叶林或禾草草原这样的植物群落的名称时,就会分别获得由松杉目或禾本科植物所构成的景观外貌的概念。但是,如果我们提到浙江植物区系或天目山植物区系时,则得不到任何景观外貌的概念。因为,在一区系内往往含有静多不同科的植物,且在同一科内可能同时具有乔木、灌木和草本。 相似文献
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Leonurus japonicus Houtt. [L. heterophyllus Sweet, L. artemisia (Lour.) S. Y.
Hu] is one of the most important traditional Chinese medicines used as a remedy for gynaeco-
logical disease since ancient times. A cytological investigation on the species was carried out
and the materials for chromosomal examination were collected from 26 localities in 20 provi-
noes and autonomous regions of this country. The number of chromosomes in root tip cell of
the species was found to be 20 on the whole (Tab. 1:1), agreeing with those reported by Ma and
al.[2] and probably by Chuang and al.[3] as well.
The genus Leonurus L. is variable in its chromosomes with an aneuploidy of x=9, 10 and
12. The present authors would propose that the primitive basic number of chromosome in the
genus is 9, and thus both 10 and 12 are derived, for: (1) among the 9 species (including 1 sub-
species) heretofore cytologically examined, x=9 occurring in 66.7%, x=10 occurring in 22.2%,
while x=12 occurring only in 11.1%; (2) in generaclosely related to the genus under considera-
tion, such as Panzeria, Galeobdolon and Lamium x=9 being the sole basic number.
But L. japonicus exhibits a mixoploidy of 2n=20 (occurring at the rate of 53.30% of the
total amount of cells examined), 2n=18 (30.70%), and 2n=16 (15.99%) in our work. (Table
1). Since the original basic number of chromosome of the genus is 9 as proposed above, 2n=
20 would be considered as a derived one and the occurrence of 2n=18 probably suggests an
early evolutionary trend of 2n=18→20 of the pecies in question. 相似文献
6.
本文通过对半夏属Pinellia 5个种10个群体的染色体计数和珠芽数量统计，首次报道了5个染色体数目，同时发现珠芽的发生与染色体基数及多倍化程度有关：x=13的类群无珠芽，而x=9的有珠芽；在有珠芽的半夏P．ternata(Thunb．)Breit．中，平均每叶珠芽数随倍性的提高而增大。半夏是一个多倍体复合种，起源于无珠芽、染色体基数为x=7～9的二倍体祖先，可能是在该属的早期进化中由鹞落坪半夏P.yaoluopingensis X．H．Guo et X．L.Liu的x=13经非整倍性跌落而成，在发生上比鹞落坪半夏进化。 相似文献
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一、分类系统和系统发育 为植物界最大的类群——被子植物建立一个能真正反映植物的进化历史和系统发育(phylogeny)的分类系统一直是许多植物系统学家和进化学家所向往的。到目前为止,已经提出的被子植物分类系统至少有二十多个。问题在于这样的分类系统能否说已符合于系统发育的要求?要回答这个问题,首先必须弄清系统发育的真正含义是什么。 按严格的意义来说,系统发育(或种系发生)这个术语仅仅指以在一段持续的时间 相似文献
8.
According to the information including type material with regard to Raphiolepis
major Card. and R. indica (L.) Lindl., the morphological differences between these two
closely related taxa are largely quantitative, i.e., the former has larger leaves, flowers
and fruits, and longer petioles and pedicels than the latter. But since these characteri-
stics are rather variable, they can hardly be proven to be sound in separating these two
taxa as distinct.
By using methods of quantitative analysis with scatter diagrams on herbarium ma-
terials, we have found that the characteristics used to discriminate the two taxa either
tend to display continuous variational patterns, or vary at random. Both eases suggest
that the morphological variations of individual sample plants are probably due to the dif-
ferent modes of growth or development of plants in response to varied environments.
Since these two taxa are taxonomically inseparable from each other as a whole, it seems
advisable to treat them as one single species. Thus, the lately published R. major Card.should be reduced to a synonym of R. indica (L.) Lindl. 相似文献
9.
This paper, which consists of a part of pertinent data obtained through a cri-
tical revision of the genus Lonicera of China. discusses 28 noteworthy species and infra-
specific taxa. Among them, 3 subspecies and 1 variety are new grades and combinations. Be-sides, 31 species, 11 varieties and 6 forms have been reduced to synonyms. 相似文献
10.
The present paper embodies the results of a karyotypic analysis for the
species Lycoris rosea Traub et Moldenke. The voucher specimen, J. Z. Lin 004 is pre-
served in the Herbarium of Hanchow Botanical Garden. The chromosome number in root
tip cells is found for the first time to be 22, and the karyotype is shown to be an asymme-
trical one with rod-shaped chromosomes. A photomicrograph, the karyotype and the idiog-
ram are shown in Figs. 1-2. According to Levan et aL.[5], the karyotype formula of the
species is 2n=22=22t. But based on the classification presented by Bose and Flory[1], the
karyotype formula should be expressed as 2n=22 =C22, and the chromosomes are all with
subterminal constrictions.
If regarding 11 as the basic number and centric fusion as the major tendency of karyo-
type evolution as proposed by Inariyama[2], Stebbins[6], and Jones[3,4] in particular, L. rosea
would be considered as one of the most primitive species in Lycoris from point of view of
karyotype evolution. Reciprocal translocations and centric fusions would give rise to V-sha-
ped chromosomes. Consequently, the successive decrease in chromosome number may have
taken place in the speciation of the genus under discussion. Yet further evidence seems ne-cessary for the verification of the speculation. 相似文献