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1.
In the work mitotic chromosomes in root-tips of 7 species native to Sichuan Pro-
vince were examined and their karyotypes were analysed based on 7-8 cells at mitotic meta-
phase, using Levan et al.'s (1964) nomenclature. The list of species and origin of the materials
used in this work are provided in the appendix. The micrographs of mitotic metaphase of all
the materials are shown in Plates 1 and 2; the idiograms in Fig. 1, 1-9, and the parameters
of chromosomes are provided in Tables 1-9. All the chromosome countings and karyotypes in
this paper are reported for the first time.
Characteristics of the karyotypes may be summarized as follows:
1. 2n=38 are found in all the materials except A. sichuanensis, which has 3 cytotypes, i.e,
2n=38+5B, 2n=38+lB and 2n=38+OB (Plate 2, 1-2, Fig. 1, 5-6).
2. The karyotypes are of two major types: the karyotype of A. flaviflora falls into 3C in
Stebbins's (1958, 197l) classification of karyotypes and those of all the other species into 2C.
The two types are also different from each other in the number of large and medium-sized
chromosomes pairs and morphology of the first pair of chromosomes (compare Plate 2, 5, Fig.
1, 9 with the other micrographs and idiograms).A. flaviflora with the karyotype 3C also differs
from the other species in a series of gross morphological characters: the species is of a yellow and
campanulate corolla.
3. The species with caespitose leaves (A. caespitosa and A. omeiensis) have essentially the
same karyotype, which is rather different from those of the species with scattered leaves. There
are two pairs of small sm chromosomes (arm ratio ≥1.90) in the former karyotype (Tables 1
and 3), but all the small chromosomes are m or sm with arm ratio <1.80 in the latter karyotypes. 相似文献
2.
Paeonia suffruticosa Andrews subsp. spontanea (Rehder) S. G. Haw et L. A.
Lauener ( ＝P. spontanea ＝ P. jishanensis) has been considered as the wild form of widely
cultivated P. suffruticosa. However, the subspecies differs from the cultivated one in
shape, division and indumentum of leaves and reproductive biology. As a result of extensive
field work, a form with two individuals in Yinping Shan, Caohu, Anhui, and Songxian,
Henan, are found to be extremely similar to P. suffruticosa, but apparently different from
P. jishanensis. The form is considered to be the wild one of P. suffruticosa and described as new: P. suffruticosa subsp, yinpingmudan Hong, K. Y. Pan et Z. W. Xie. 相似文献
3.
A karyotypical analysis of Anemarrhena asphodeloides Bung. of the monotypic genus
Anemarrhena Bung. (Liliaceae) was carried out for the first time. The number of chromo-
somes in root-tip cell of the species was found to be 22, agreeing with that reported by Sato[12], although inconsistent in some other respects, such as position of centromeres, length of chromosomes, and nucleoli, etc. (Table 1 ). According to the terminology defined by Levan et al.［8］, the karyotype formula is therefore 2n=22=2sm (SAT)+2sm+18m.
Photomicrographs of the chromosome complements and idiogram of the karyotype are given
Fig. 1 and 2).
The karyotype of Anemarrhena asphodeloides shows explicitly to be asymmetrical, with three pairs of long chromosomes and eight pairs of short chromosomes. This specialized feature, when considered together with the rare occurrence of the basic chromosome number of 11 of the genus within the Tribe Asphodeleae of Liliaceae (see Table 1), suggests that the genus Anemarrhena is probably a rather specialized one, which has scarcely any intimate relationship with the other genera of the above tribe. The fact that this specialized karyotype is associated with certain trends of morphological specialization, such as flowers possessing three stamens only, gives support to the above suggestion. But, it is impossible to draw a more precise conclusion without a more thorough and comprehensive investigation of the species in question. 相似文献
4.
1) The Compositae in Tibet so far known comprise 508 species and 88 genera,
which nearly amounts to one fourth of the total number of genera and one third of the
total number of species of Compositae in all China, if the number of 2290 species and 220
genera have respectively been counted in all China. In Tibet there are all tribes of Com-
positae known in China, and surprisingly, the large tribes in Tibetan Compositae are
also large ones in all China and the small tribes in Tibet are also small ones in all China.
Generally speaking, the large genera in Tibet are also large ones in all China and the
small genera in Tibet are likewise small ones in all China. In this sense it is reasonable to
say that the Compositae flora of Tibet is an epitome of the Compositae flora of all China.
In the Compositae flora of Tibet, there are only 5 large genera each containing 30
species or more. They are Aster, Artemisia, Senecio, Saussurea and Cremanthodium. And
5 genera each containing 10—29 species. They are Erigeron, Anaphalis, Leontopodium,
Ajania, Ligularia and Taraxacum. In addition, there are 77 small genera, namely 87%
of the total of Compositae genera in Tibet, each comprising 1—9 species, such as Aja-niopsis, Cavea and Vernonia, etc.
2) The constituents of Compositae flora in Tibet is very closely related to those of
Sichuan-Yunnan provinces with 59 genera and 250 species in common. Such a situation
is evidently brought about by the geographycal proximity in which the Hengtuang Shan
Range links southeastern and eastern Tibet with northern and northwestern Sichuan-
Ynnnan. With India the Tibetan Compositae have 59 genera and 132 species in common,
also showing close floristic relationships between the two regions. Apparently the floris-
tic exchange of Compositae between Tibet and India is realized by way of the mountain
range of the Himalayas. The mountain range of the Himalayas, including the parallel
ranges, plays a important role as a bridge hereby some members of the Compositae of
western or northern Central Asia and of the northern Africa or of western Asia have
migrated eastwards or southeastwards as far as the southern part of Fibet and northern
part of India, or hereby some Compositae plants of eastern and southeastern Asia or
Asia Media have migrated northwestwards as the northern part of Central Asia.
Some of the species and genera in common to both Tibet and Sinjiang indicate that
this weak floristical relationship between these regions is principally realized through two
migration routes: one migration route is by way of the Himalayas including the parallel
ranges to Pamir Plataeu and Tien Shan, or vice versa. The other migration route is by
way of northern Sinjiang to Mongolia, eastern Inner Mongolia, southwards to Gansu,
Qinghai (or western Sichuan), eastern Tibet up to the Himalayas, or vice versa.
However, Tibet is not entirely situated at a migration crossroad of the floral ele-
ments. An ample amount of the data shows that Compositae flora have a particular
capability of development in Tibet. of the total number of species of Tibetan Com-
positae, 102 species and 1 genus (Ajaniopsis Shih) are endemic. Besides, 8 genera are re-
gional endemics with their range extending to its neighbourhood. The higher percentage
of endemics at specific level than at generic in Tibetan Compositae may be a result of
active speciation in response to the new enviromental conditions created by the uplifting
of the Himalayas. The flora in Tibetan Plateau as a whole appears to be of a younger
age.
3) The uprising of the Himalayas and of the Tibetan Plateau accompanied by the
ultraviolet ray radiation, the microthermal climate and the high wind pressure has, no
doubt, played a profound influence upon the speciation of the native elements of Tibetan
Compositae. The recent speciation is the main trend in the development of the Com-positae flora native in Tibet in the wake of upheaval of the plateau. 相似文献
5.
6.
We have described a new genus Taihangia, collected from, the south part of Taihang
Mountain in northern China. At the same time, comparative studies on Taihangia with its
related genera have been made in various fields including external morphology, anatomy
of carpels, chromosome and pollen morphology by light, scanning and transmission electron microscope. In addition, isoperoxidases of two varietier were analysed by means of polya-crylamide gel slab electrophoresis. The preliminary results are as follows:
Morphology: The genus Taihangia is perennial and has simple leaves, occasionally
with 1—2 very small reduced lobes on the upper part of petiole; flowers white, andromo-
noecious and androdioecious, terminal, single or rarely 2 on a leafless scape; calyx and cpicalyx with 5 segments; petals 5; stamens numerous; pistils numerous, with pubescent styles, spirally inserted on the receptacle in bisexual flowers, but with less number of abortive and glabrous pistils in male flowers.
In comparison with the related genera such as Dryas, Geum, Coluria and Waldsteinia,
the new genus has unisexual flowers and always herbaceous habit indicating its advanced
feature but the genus has a primitive style with thin and short hairs as compared with the genus Dryas which has long, pinnately haired styles, a character greatly facilitamg anemo-choric dissemination. The styles of Taihangia are slender and differ from those of the ge-nus Geum which are articulate, with a persistent hooked rostrum, thus adapting to epizo-ochoric dissemination to a higher degree.
The anatomy of carpels shows the baral position of ovules in the genus Taihangia like those in other related genera such as Dryas, Geum, Acomastylis, Coluria and Waldsteinia. This suggests that the new genus and its related ones are in a common evolutionary line as compared with the other tribes which have a pendulous ovule and represent a separate evolutionary line in Rosaceae. Dorsal and ventral bundles in carpels through sections are free at the base. Neither fusion, nor reduction of dorsals and vertrals. are observed. This shows that the genus Taihangia is rather primitive.
Somatic chromosome: All the living plants, collected from both Honan and Hopei
Provinces were examined. The results show that in these plants the chromosome number
is 2n= 14, and thus the basic number of chromosome is x=7. Such a diploid genus is first
found in both anemochoric and epizoochoric genera. Therefore, in this respect Taihangia is primitive as compared with herbaceous polyploid genus Geum and related ones.
Pollen: The stereostructure shown by scanning electron microscope reveals that the pollen grains of the genus Taihangia are ellipsoid and 3-colporate. There are two types of exine sculpture. One is rather shortly striate and it seems rugulate over the pollen surface; the other is long-striate. The genus Dryas differs in having only short and thick striae over the surface. The genus is similar to the genera Geum, Coluria and Waldsteinia in colpustype, but differs from them in that they all have long, parallel striae which are distributed along the meridional line.
In addition, under transmission electron microscope, the exine in the Taihangia and related genera Acomastylis, Geum, Coluria, Waldsteinia and Dryas has been shown to be typically differentiated into two distinct layers, nexine and sexine. The nexine, weakly statined, appears to consist of endoxine with no foot-layer, in which the columellae are fused, and which is thicker beneath the apertures. The sexine is 2-layered, consisting of columellae and tectum. Three patterns of tectum can be distinguished in the tribe Dryadeae: the first, in the genera Taihangia, Acomastylis, Geum, Coluria and Waldsteinia, is tectate-imperforate, with the sculpturing elements both acute and obtuse at the top and broad at the base; the second, in the genus Dryas, is semitectate, with the sculpturing elements shown in ultrathin sections rod-like and broader at the top than at the base or as broad at the top as at the base, and the third, tectate-perforate, with the sculpturing elements different in size. From the above results, the herbaceous groups and woody ones have palynologically evolved in two distinct directions, and the genus Taihangia is related to other herbaceous genera such as Acomastylis, Geum, Coluria and Waldsteinia, as shown in the electron microphotographs of ultrathin sections. The genus Taihangia, however, is different from related herbaceous genera in that the pollen of Taihangia is dimorphic, i.e. in addition to the above pattern of pollen another one of the exine in Taihangia is rugulate, with the sculpturing elements shown in the ultrathin sections being obtuse or emarginate and nearly as broad at the top as at the base.
The interesting results obtained from the comparative analysis of morphology, ana-
tomy of carpels, chromosome countings, microscopic and submicrosocopic structures of pollen may enable us to evaluate the systematic position of Taihangia and to throw a new light on evolution of the tribe Dryadeae. It is well known that the modes of dissemination of rosaceous fruits play an important role in the expansion and evolution of the family. The follicle is the most primitive and the plants with follicles, like the Spiraeoideae, are mostly woody and mesic, while the achene, drupe and pyrenarium are derived. In Rosoideae having a achene is a common feature. Particularly in the tribe Dryadeae, which is distinguished from the other related tribes by having orthotropous ovules, the methods of dissemination of fruits have developed in three distinct specialized directions: anemochory with long, plumose styles (e.g. Dryas), formicochory or dispersed by ants or other insects, with the deciduous styles (e.g. Waldsteinia and Collria),and epizoochory with the upper deciduous stigmatic part and the lower persistent hooked rostrum, an adhesive organ favouring epizoochory dissemination (e. g. Geum and related taxa). Taihangia is a genus endemic to mesophytic
forest area of northern China. Due to its narrow range and specific habit as well as pubescent styles, neither perfectly adapted to anemochory nor to epizoochory, the genus Taihangia might be a direct progeny of the ancestry of anemochory. Maintaining the diploidy and having an ntermediate sculptural type of pollen, the new genus might probably represent a linkage between anemochory and zoochory (including epizoochory and dispersed by ants).
Experimental evidence from isoperoxidases shows the stable zymograms of root and
roostoks. The anodal isozyme of T. rupestris var. rupestris may be divided into 6 bands:
A, B, C, D, E, F, and T. rupestris var. ciliata into 4 bands: A, B, C, G. The two varietiesof the species share 3 bands: A, B, C. However, D, E and F bands are characteristic of var. rupestris and G band is limited to var. ciliata. As far as the available materials are concerned, the analysis of isoperoxidases supports the subdivision of the species into two varieties. 相似文献
7.
张志耘 《中国科学院研究生院学报》1988,26(5):394-403
The morphological characters in the genus Orobanche were evaluated from the
taxonomic point of view. The author finds that the plants of this genus are relatively similar
to each other in respect to characters of vegetative organs, fruits and seeds. But the differences
in the floral structures can be served as a basis for delimitating infrageneric taxa. The seed
coat of 18 species and pollen grains of 6 species were also examined under scanning electron
microscope (SEM). They seem to have little significance for distinguishing species.
The result supports G. Beck’s (1930) division of the genus Orobanche into 4 sections, of
which 2 occur in China, based on the characters of the inflorescence, bracteoles and calyx.
The author considers that some characters, such as anther hairy or not, upper lip of corolla
entire or not, lower lip longer or shorter than the upper one, the state of corolla-tube inflec-
tion and the hair type of filaments and plants, are important in distinguishing Chinese species.
A key to the species of Orobanche in China is given.
This genus consists of about 100 species, and is mostly confined to Eurasia, with over 60
species found in Caucasus and Middle Asia of USSR, where may be the mordern distribu-
tional centre.
Orobanche L. in China is represented by 23 species, 3 varieties and l forma. As shown in
Table 1, most species (12 species) are found in Xinjiang, which clearly shows a close floristic
relationship between this region and Middle Asia of USSR. 6 species are endemic to China,
of which 4 are confined to the Hengduan Mountains (Yangtze-Mekong-Salwin divide).
The relationships between this genus and related ones of Orobanchaceae are also discussed.
The author holds the following opinions: the genus Phelypaea Desf. should be considered as a
member of Orobanche L. Sect. Gymnocaulis G. Beck, the monotypic genus, Necranthus A.
Gilli endemic to Turkey, is allied with Orobanche L. Sect. Orobanche, the monotypic genus,
Platypholis Maxim, endemic to Bonin Is. of Japan, is far from Orobanche L. in relation and
should be regarded as a separate genus.
The 11 OTU’s, including all the sections of Orobanche L. and 7 genera of Orobanchaceae,
and 15 morphological characters were used in the numerical taxonomic treatment to test the
above-mentioned suggestions. After standardization of characters, the correlation matrices were
computerized. The correlation matrices were made to test the various clustering methods. At
last the UPGMA clustering method was chosen and its result is shown in a phenogram. The
result of numerical analysis is basically in accordance with the suggestions. 相似文献
8.
9.
Xizang (Tibet) is rich in Leguminosae flora, comprising 41 genera and 254 species
so far known, exclusive of the commonly cultivated taxa (including 11 genera and 16
species). There are 4 endemic genera (with 8 species), 10 temperate genera (with 175
species) and 19 tropical genera (with 46 species) as well as the representatives of those
genera whose distribution centers are in East Asia-North America, Mediterranean
and Central Asia.
1. There are altogether 4 endemic genera of Leguminosae in this region. Accord-
ing to their morphological characters, systematic position and geographical distribution,
it would appear that Salweenia and Piptanthus are Tertiary paleo-endemics, while
Straceya and Cochlianths are neo-endemics. Salweenia and Piptanthus may be some
of more primitive members in the subfamily Papilionasae and their allies are largely
distributed in the southern Hemisphere. The other two genera might have been derived
from the northern temperate genus Hedysarum and the East Asian-North American
genus Apios respectively, because of their morphological resemblance. They probably
came into existanc during the uplifting of the Himalayas.
2. An analysis of temperate genera
There are twelve temperate genera of Leguminosae in the region, of which the
more important elements in composition of flora, is Astragalus, Oxytropis and Cara-
gana.
Astragalus is a cosmopolitan genus comprising 2000 species, with its center
distribution in Central Asia. 250 species, are from China so far known, in alpine zone of
Southwest and Northwest, with 70 species extending farther to the Himalayas and
Xizang Plateau.
Among them, there are 7 species (10%) common to Central Asia, 12 species (15.7%)
to Southwest China and 40 species (60%) are endemic, it indicates that the differentia-
tion of the species of the genus in the region is very active, especially in the subgenus
Pogonophace with beards in stigma. 27 species amounting to 78.5% of the total species of
the subgenus, are distributed in this region. The species in the region mainly occur in
alpine zone between altitude of 3500—300 m. above sea-level. They have developed into
a member of representative of arid and cold alpine regions.
The endemic species of Astragalus in Xizang might be formed by specialization of
the alien and native elements. It will be proved by a series of horizontal and vertical vicarism of endemic species. For example, Astragalus bomiensis and A. englerianus are
horizontal and vertical vicarism species, the former being distributed in southeast part
of Xizang and the latter in Yunnan; also A. arnoldii and A. chomutovii, the former
being an endemic on Xizang Plateau and latter in Central Asia.
The genus Oxytropis comprises 300 species which are mainly distributed in the
north temperate zone. About 100 species are from China so far known, with 40 species
extending to Himalayas and Xizang Plateau. The distribution, formation and differ-
entiation of the genus in this region are resembled to Astragalus. These two genera are
usually growing together, composing the main accompanying elements of alpine mea-
dow and steppe.
Caragana is an endemic genus in Eurasian temperate zone and one of constructive
elements of alpine bush-wood. About 100 species are from China, with 16 species in Xi-
zang. According to the elements of composition, 4 species are common to Inner Mon-
golia and Kausu, 4 species to Southwest of China, the others are endemic. This not only
indicates that the species of Caragana in Xizang is closely related to those species of
above mentioned regions, but the differentiation of the genus in the region is obviously
effected by the uplifting of Himalayas, thus leading to the formations of endemic species
reaching up to 50%.
3. An Analysis of Tropical Genera
There are 19 tropical genera in the region. They concentrate in southeast of Xizang
and southern flank of the Himalayas. All of them but Indigofera and Desmodium are
represented by a few species, especially the endemic species. Thus, it can be seen that
they are less differentiated than the temperate genera.
However, the genus Desmodium which extends from tropical southeast and northeast
Asia to Mexio is more active in differentiation than the other genera. According to Oha-
Shi,s system about the genus in 1973, the species of Desmodium distributed in Sino-Hima-
laya region mostly belong to the subgenus Dollinera and subgenus Podocarpium. The
subgenus Dollinera concentrates in both Sino-Himalaya region and Indo-China with 14
species, of which 7 species are endemic in Sino-Himalaya. They are closely related to
species of Indo-China, southern Yunnan and Assam and shows tha tthey have close con-
nections in origin and that the former might be derived from the latter.
Another subgenus extending from subtropical to temperate zone is Podocarpium.
Five out of the total eight species belonging to the subgenus are distributed in Sino-
Himalaya and three of them are endemic.
An investigation on interspecific evolutionary relationship and geographic distribu-
tion of the subgenus shows that the primary center of differentiation of Podocarpium
is in the Sino-Himalaya region.
Finally, our survey shows that owing to the uplifting of the Himalayas which has
brought about complicated geographic and climatic situations, the favorable conditions
have been provided not only for the formation of the species but also for the genus in cer-tain degree. 相似文献
10.
11.
本文报道了毛茛(Ranunculus japonicus Thunb．)在江西发现的核型变异。R．japonicus
的基本核型为2n=14=6m+4sm十4st (2SAT)；变异核型为2n=14十1B=6m+4sm+4st
(2SAT)十1B和2n=14=6m+6sm(2SAT)+2st。核型变异表现在增加B染色体或第4对同源染色体异形及第6对随体染色体臂比变化。 相似文献
12.
13.
李林初 《中国科学院研究生院学报》1986,24(5):376-381
本文首次报道秃杉的核型为K(2n)=22=16m+6sm, 3号染色体具“长着丝点区 域”。似具比同属的台湾杉(18m+4sm)进化的趋势。它们均为"2B"。从国产杉科植物的 核型类型看,似见"2B"的台湾杉属与"1B"的杉木属和"1A"的水杉属、水松属、柳杉属的亲缘关系依序由近到远并比它们进化。本作者还观察了秃杉的核仁数目和多微核现象。 相似文献
14.
A comparison of morphology, karyotype and the chemical compounds among
“Jinxiong”, Ligasticum chuanxiong Hort. and L. chuanxiong cv. Fuxiong shows that “Jin-
xiong”, like L. chuanxiong cv. Fuxiong, is a triploid and its karyotype is similar to that of
L. chuanxiong with the formula K(2n)=33=24m+6sm+3st(SAT). Thin-layer chromato-
graphy of essential oils extracted from stem tubers confirms that the three taxa are extremely
alike in chemical compounds. Using the features of leaves and the forms of stem tubers, they
can be easily distinguished. A new triploid cultivar of L. chuanxiong Hort. i.e.L. chuan-xiong cv. Jinxiong is described for “Jinxiong” in the present paper. 相似文献
15.
李林初 《中国科学院研究生院学报》1988,26(5):371-377
本文分析了池杉Taxodium ascendens 的核型，全由中部和近中部着丝点染色体组成，
核型公式为K(2n)=22=20m+2sm，属“1A”类型。它的特点是10号染色体具“长着
丝点区域”结构。池杉染色体的相对长度组成为2n=2L+8M2+12M1。通过与落羽杉
的“1A”和墨西哥落羽杉的“2A”核型进行比较，似见它们的进化水平以落羽杉、池杉，墨西
哥落羽杉之序递增。 落羽杉属植物的核型公式均为K(2n)=22= 20m+2sm。 本文还就
核型、生态环境和地理分布(包括化石)资料讨论了落羽杉属的次生遗传歧异中心和可能的演
化式样。 相似文献
16.
葱属粗根组5种材料的核型研究 总被引：1，自引：0，他引：1
本文分析了葱属Allium粗根组Sect．Bromatorrhiza Ekberg五群材料的核型。多星韭Allium
wallichii Kunth有两个类型：第一类型是二倍体，染色体组公式为AA，核型公式为K(2n)=2X=
14=2m(SAT)+2m+10sm，属2A型；第二类型是同源四倍体，染色体组公式为AAAA, 核型公
式为K(2n)＝4X＝28＝2m(SAT)+6m十20sm,属2A型。宽叶韭Allium hookeri Thwaites有
三个类型： 第一类型是双基数同源异源三倍体，染色体组公式为AAB1,核型公式为 K(2n)＝2X+
x'＝22＝(12sm+2t)十(1m十45m+1st+2t)， 属3A型； 第二类型也是双基数同源异源三倍
体，能配对的两个染色体组染色体大小和形态与第一类型大体相似，不能配对的一个染色体组染色体
大小和形态与第一类型有明显区别，其中至少有两条染色体发生了罗伯逊易位，出现一条很大的染色体
和一条很小的染色体，染色体组公式为AAB2，核型公式为K(2n)=2x+x'＝22=(12sm+2t)+
(3m+1sm十2st+2t)，属3A型；第三类型相当于第一类型染色体的自然加倍，是双基数同源异源
六倍体，染色体组公式为AAAAB1B1，核型公式为K(2n)=4X十2x'＝44＝(24sm+4t)十(2m+
8sm十2st+4t)，属3A型。 相似文献
17.
本文报道了国产头蕊兰属植物银兰和金兰的核型： (1)银兰为 2n=34=10m十
14sm＋10st。金兰有两种细胞型，A型为2n＝34＝8m+16sm十10st；B型为2n=34=
8m+22sm十4st。 后者为一个由染色体结构变异所产生的易位同型纯合子 (translocation
homozygote)，是由A型通过第1对染色体的短臂与第3对染色体的长臂之间的易位所产生。
在植株外部形态上未见明显差异。 (2)按Stebbins(1971)的标准，三种核型均属不对称的 “3C”型。 相似文献
18.
秦岭地区10种百合科植物核型报道 总被引：1，自引：0，他引：1
本文对秦岭地区的Polygonatum的2种，Hosta的2种和Smilax discotis，Cardiocrinum
giganteum，Asparagus filicintus，Reineckia carnea，Tupistra chinensis，Rohdea japonica做了核型分析。其中有4种的核型为国内首次报道。本义对不同产地的玉竹gonatum odoratum)的核型进行了对比，讨论了其核型进化的可能途径。 相似文献
19.
本文对贵州大树茶7种1变种11类型的核型进行了分析。结果表明，这些种类均为二倍体2n＝30。五室茶Camellia quinquelocularis 2n＝30＝24m+6sm；四球茶C．tetracocca 2n＝30=22m+8sm；大理茶C．taliensis 2n=30＝22m+8sm；秃房茶C．gymnogyna 2n＝30＝22m+6sm+2st与2n=30＝20m+8sm+2st；假秃房茶C. gymnogynoides 2n＝30=22m+6sm+2st与2n＝30=20m+8sm+2st；榕江茶C. jungkiangensis 2n＝30+20m+8sm+2st；茶C．sinensis 2n=30＝20m+8sm+2st以及变种淡红花茶C．sinensis var．ruolla 2n＝30=20m+8sm+2st；均属2A核型。染色体结构变异在茶组植物演化中起了重要作用。所划分的两大类核型，即m和sm类与m，sm，和st类是与其子房室数，即5室和3室相一致的。根据核型的不对称性程度、外部形态及生化分析，探讨了各种类的亲缘关系与系统演化途径，论证了茶组植物的原产地是位于滇、桂、黔毗邻交汇处的云贵高原，探讨了茶组植物的分类学问题。 相似文献
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本文对陕西、四川和河北的Paris 2种，Cardiocrinum giganteum, Smilacina 2种，Allium
2种， Asparagus 2种，以及Convallaria majalis 的核型作了分析，其中Paris polyphylla var.
latifolia， Smilacina henryi 和 Allium ovalifolium 的染色体报道为第一次。 首次发现Perisverticillata 中四倍体细胞宗的存在。本文对Paris的核型、地理分布和分类作了分析讨论。 相似文献