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1.
A karyotypic analysis of Lycoris longituba Y. Hsu et Fan was carried
out. The voucher specimen, Z. G. Mao 10501, is preserved in the Herbarium of Hangchow
Botanical Garden. The chromosome number in root tip cells of the species is found for the
first time to be 16, among which 6 are large, V-shaped with submedian primary constrictions, and the other 10 are short, rod-shaped with terminal primary constrictions. Photomicrograph of the chromosome complement and idiogram are given in Fig. 1-3 respectively.
The karyotype formula of the species is therefore 2n=16=6m+6t+4t (SAT) in the light
of the chromosomal terminology defined by Levan and al.[5]
Based on the view stressed by Jones[3] and Brandham[4], successive fusion of the chromosomes should be taken as the essential mechanism for karyotype evolution and speciation in Lycoris. Reciprocal translocation, with the loss of one of the centromeres, might be
the mechanism of origin for a V chromosome. It is, then, suggested that the decrease in chromosome number as a result of fusion of the rods with terminal or subterminal primaryconstrictions has taken place in the speciation of L. longituba. 相似文献
2.
Li Lin-Chu 《植物分类学报:英文版》1988,26(5):371-377
The present paper deals with the karyotypic analysis of Taxodium ascendens Brongn.
The somatic chromosomes in root-tip cells of the plant are found to be 2n =22, all with median
and submedian constrictions. A character of the karyotype is that the chromosome 10 has
a long kinetochore region (Plate 1:1). According to the terminology defined by Levan et al.[18],
the karyotype formula is k(2n)=22=20m+2sm, which is different to Huang et Hsu’s[8]
K(2n)=24=22m+2B(m). The karyotype belongs to “lA” of Stebbins’[24] karyotypic symmetry
and is generally regarded as a relatively primitive one. The species’ chromosome complement
is 2n=22=2L+8M2+12M1 according to I.R.L.difined by Kuo et al.[15] based on relative length.
The lengths, arm ratios and types of chromosomes of the species are given in Table 1-I. The
morphology of the chromosomes and the karyotype, are given in Plate 1:1.
In the light of the works of Schlarbaum et al.[21] and Mehra et al.[17], K(2n)=22=20m
(2SAT)+2sm and 2n=22=2L+6M2+14M1 are for T. distichum (L.) Rich. (see Table 1-II),
K(2n)=20m+2sm and 2n=22=4L+4M2+12M1+2S for T. mucronatum Tenore (see Table
1-III, Plate 1:2), which belong to “lA” and “2A” respectively.
The differences between three species in the ratio of the longest to the shortest chromosome,
I.R.L. and the proportion of chromosomes with arm ratio >2 show that the karyotype of T.
mucronatum is the most advanced and that of T. distichum the most primitive. The present
author suggests that the sequence of evolutionary advance be T. distichum, T. ascendens, T. mucronatum.
Based on the evidence from the karyotype analyses, ecology and geographical distribution
(including fossil), the secondary center of genetic diversity (Fig. 1) and the probable evolu-tionary pattern (Fig. 2) of Taxodium are discussed. 相似文献
3.
Li Lin-Chu 《植物分类学报:英文版》1986,24(5):376-381
The present paper deals with the cytological investigation of Taiwania flousiana
Gaussen. The somatic chromosomes in root-tip cells of the plant are found to be 2n=22 for
the first time, all with median and submedian constrictions. According to the terminology defined by Levan et al.[11], the karyotype formula is K(2n)=16m+6sm, which belongs to “2B”
of Stebbins'[16,17] karyotypic symmetry and is generally regarded as a relatively primitive one.
The species' chromosome complement is 2n=22=4L+6M2+8M1+4s according to the standard
defined by Kuo et al.[10] based on relative length.
The nucleolus number in resting root-tip cells of T. flousiana is found to be 1-5 (Table
3). The percentage of cells with two nucleoli is 77.6%, and those with five nucleoli, the highest
number ever found by me, is only 1.6%. A few cells with many micronuclei are found in this
species for the first time (Plate 1, 1).
Although T. flousiana and T. cryptomerioider have the same “2B” type of karyotypic
symmetry, the differences in the arm ratio and the index of the karyotypic asymmetry (Table
2) show that the karyotype of the former is less symmetrical than that of the latter, so the
former may be a little more advanced than the latter.
The basic karyotype (2B) of Taiwania is more related to that of Cunninghamia (1B)[3]
than to that (1A) of Metasequoia[5], Glyptostrobus[4] and Cryptomeria[3]. Wang et al.[1], have
reached the similar conclusion from the embryological study. 相似文献
4.
Karyotype analysis for the species Reineckia carnea (Andr.) Kunth of the monotypic genus Reineckia Kunth is given for the first time. The number of chromosomes in
root-tip cell was found to be 38, which is in accord with those reported by most of the previous authors[5,7,8,9,11,12,]. The somatic complement shows a slight variation in size, i.e., the 2,
3, 5, 6, 7th pairs of the chromosomes have submedian constrictions, while the other pairs
have median centromeres. The karyotype is therefore a rather symmetrical one, and according to the chromosomal terminology defined by Levan et al[4], the karyotype formula of
the species is 2n=38=28 m+10 sm. In spite of the presence of two nucleoli in the telophase as observed by the authors and Noguchi[8] as well, the two corresponding Sat-chromosomes have not been found. Photomicrograph of the chromosome complement and idiogram are given in Fig. 1 and 2 respectively. 相似文献
5.
A karyotypical analysis of Anemarrhena asphodeloides Bung. of the monotypic genus
Anemarrhena Bung. (Liliaceae) was carried out for the first time. The number of chromosomes 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
6.
The genus Lycoris (Amaryllidaceae) consists of about 20 species, all of which are
confined to temperate China, Japan and Korea.
Cytological investigations, including a reexamination of the karyotypes of 14 taxa, measurements of relative nuclear DNA content, and meiotic configuration observations on some specific
forms and interspecific hybrids, have been carried out by the present authors in order to re-evaluate the mode of karyotype evolution and the role of hybridization in the speciation of Lycoris.
These have resulted in a new theory for explaining the karyotype evolution in the genus, which
will be considered elsewhere. The present paper deals with observations on karyotypes of 11
species, 1 variety and 2 artificial hybrids.
Results obtained through karyotype analysis, as shown by the data in Table 1, Plates I-VI
and Figs. 1-2, reveal that: (1) the karyotypes of Lycoris rosea, L. radiata var. pumila, L. sprengeri, L. haywardii, L. caldwellii, L. squamigera and L. radiata are, on the whole, consistent with
those reported by the previous authors[1,2,3,4,5,8,10,12];(2) the I (rodshaped) chromosomes of L.
chinensis and L. longituba are all T’s (telocentric) instead of t’s (acrocentric) or t(Sat)’s;
(3) the three materials of L. aurea of different sources have shown a karyotypic differentiation:
one with 2n=14=8m+6T, and the others with 2n=16=6m+10T: (4) both of the karyotypes
of L. straminea and L. albiflora are 2n=19=3V+6I, inconsistent with 2n=16=6V+10I for the
former and with 2n=17=5V+12I for the latter as reported by Inariyama (1953), Bose and
Flory (1963) and Kurita (1987).
The following aspects are worthwhile discussing:
1. The types of chromosomes.
Karyotype analyses reveal the existence of three major chromosome types in Lycoris: (1)
m (metacentric) chromosomes: (2) t (acrocentric) chromosomes, with short arms, (3) T (telocentric) chromosomes, sometimes with dot-like terminal centromeres. To distinghish t’s from
T’s is of paramount importance for solving the problem of karyotype evolution in Lycoris.
Bose (1963) pointed out that in the species with 2n=22, all I chromosomes were t’s, while in
species with 2n=12-16, all I chromosomes were T’s. Our results of chromosome observations
are consistent with Bose’s remarks. Some authorst[3,6] have probably mistaken the dot-like terminal centromeres of T’s of L. longituba and L. chinensis as the short arms of t’s.
2. The significance of Robertsonian change in karyotype evolution.
Although chromosome numbers and karyotypes are very variable in Lycoris, as shown in
Table 1, the total number of arms of a chromosome complement of any species is always multiples of 11. Hence, it seems likely that Robertsonian changes have taken part in karyotype
alteration, The genus has a series of basic chromosome numbers: 6, 7, 8 and 11. But which is
the most primitive one? It is uncertain whether a successive decrease in chromosome numbers
as a result of Robertsonian fusion or a gradual increase in chromosome numbers brought about
by fission (fragmentation) has been the essential mechanism for karyotype evolution and speciation in Lycoris. These problems are of crucial importance and will be discussed in our
subsequent papers.
3. The origin of polyploids.
As evident from Table 1, there are two levels of ploidy differentiation in Lycoris: (1) di ploids with 2n=22 or the equivalent of 22, (2) triploids with 2n=33 or the equivalent of 33.
The most common way of origination of triploids in plants is the hybridization of diploids with
Tetraploids. But tetraploids have never been found in Lycoris. Thus, it is suggested that the
triploids have originated from the combination of an unreduced gamete of a diploid with a
normal gamete of another diploid.
4. The role of hybridization in speciation.
Results of karyotype analyses show that hybridization has taken an important part in the
speciation of Lycoris. Two types of hybrids have been found: (1) 2n=19= 3V+ 16I, L. straminea, L. albiflora and the two artificial hybrids L. sprengeri×L. chinensis and L. haywardii×
L. chinensis all possess this karyotype. It could be seen from the above chromosome number and
karyotype that this sort of karyotype is exactly half of the total sum of 2n=22I and 2n=16=
6V+10I. It is, therefore, quite evident that taxa possessing this karyotype are all diploid
hybrids of 2n=22 and 2n=16, (2) 2n=27=6V+21I, L. caldwellii and L. squamigera possess
this karyotype. It is reasonable to assume, too, that they are segmental allotriploids and have
arisen from the combination of an unreduced diploid gamete of 2n=16 and a normal haploid
gamete of 2n=22. The origin of the hybrid karyotype 2n=17=5V+12I reported by Inari-
yama (1953) is similar to that of 2n=19, except that one of the parents possesses 2n=12=
10V+2I instead of 2n=16=6V+10I. The origin of the other hybrid karyotype 2n=30=3V+
27I reported by Bose (1963) is similar to that of 2n=27, but the diploid gamete comes from
taxa possessing 2n=22 instead of 2n=16. 相似文献
7.
8.
Lycoris sprengeri Comes ex Baker is endemic to China. Reported in the present
paper are the chromosomes number and karyotypes for two wild populations of the species
from Anhui. ( 1 )Caishi population has a karyotype 2n=33=9st+21t+3T. The length of
chromosomes ranges from 5.58~9.15μm. The karyotype belongs to Stebbin’s (1971)
“4A”. (2)Longyashan populations have two karyotypes. The karyotype formula of the type
I is 2n=22=8st+14t, with chromosomes ranging from 6.88~9.15μm. The karyotype
belongs to “4A”. The karyotype formula of the type Ⅱ is 2n=22=1m+1sm+14st+6t,
with chromosomes ranging from 7.20~15.80μm. The karyotype belongs to “3B”. The
triploid type of L. sprengeri was discovered in Anhui for the first time. The karyotype 2n=22 =1m+1sm+14st+6t in diploid type of this species is here reported for the first time.The Robertsonian change plays a key role in karyotype evolution of Lycoris. 相似文献
9.
10.
The karyotypes of three of the four extant species of the genus Auliscomys (A. micropus, living in central [2n = 32, NF = 34] and southern [2n = 34, NF = 36, 37] Chile; A. sublimis [2n = 28, NF = 32] and A. boliviensis [2n = 22, NF = 32], which inhabit the Andean Altiplano) were analyzed. Comparisons of G-, C-, and AgNOR-banded karyotypes showed that extensive conservation of entire chromosomes and chromosomal regions had occurred during the evolution of this genus, with centromeretelomere tandem fusions and centric fusions probably being the most frequent chromosome changes. A chromosomal phylogeny, based on the chromosome homoeologies detected and parsimonious analysis of the nature and distribution of the inferred chromosomal changes, is proposed. This hypothetical phylogeny assumes that the ancestral telocentric karyotype would have undergone three consecutive tandem fusions, first originating the 2n = 32 (NF = 34) karyomorph exhibited by present-day specimens of A. micropus captured in central Chile and then the 2n = 28 (NF = 32) karyotype of A. sublimis. Subsequent centric fusions involving the tandem-fusion products would presumably have generated the 2n = 22 (NF = 32) A. boliviensis karyotype. Assuming some conditions related to early geographic distribution, this chromosomal phylogeny is in agreement with a paleogeographic model, which explains the present distribution of living Auliscomys species mainly on the basis of geologic and climatic events.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
11.
二倍体石蒜在安徽发现 总被引:13,自引:2,他引:13
本文以根尖细胞为材料,观察了石蒜Lycoris radiata(L′Her.)Herb.三个不同居群植物的染色体数目和核型,发现石蒜为一复合体,包括两种不同类型:(1)三倍体类型,主要包括一群以鳞茎无性繁殖的园艺栽培植株,其染色体数目和核型为2n=33=33t(st),属“4A”核型,且极其稳定。(2)二倍体类型,主要包括一群野生植株,变异较大,我们发现有下列几种情况:一是芜湖产石蒜(L.radiata)的野生材料,其染色体数目和核型为2n=21+1B=1m+12st+8t+1B,属“3A”核型,在石蒜种内迄今未见有类似报道;另一是黄山产野生材料,观察到两个细胞型,绝大多数细胞为2n=22=12st+1Ot,极个别细胞出现2n=22+1B=6st+14t+2T+1B的情况,均属“4A”核型。芜湖和黄山野生材料的染色体数目和核型均为首次报道。石蒜(L.radiata)的二倍体类群也是首次在安徽发现。 相似文献
12.
七种药用植物的染色体研究 总被引:4,自引:1,他引:4
对山东7种药用植物的染色体进行了研究。结果表明:田旋花(ConvolvulusarvensisL)的染色体数目为2n=78;蜜柑草(PhylanthusmatsumuraeHavata)的染色体数目为n=88;挂红灯(PhysalisalkekengiLvarfrancheti(Mast)Makino)的染色体数目为2n=24,核型公式为K(2n)=24=2m+18sm+2st+2st(sat),核型“2A”型;无剌曼陀罗(DaturastramoniumLvarinermis(Jacq)SchinzetThel)的染色体数目为2n=24,核型公式为K(2n)=24=20m+4sm,核型“1B”型;决明(CasiatoraL)的染色体数目为2n=26,核型公式为K(2n)=26=24m+2sm,核型“1A”型;荔枝草(SalviaplebeiaRBr)的染色体数目为2n=16,核型公式为K(2n)=16=6m+10sm,核型“2A”型;车前(PlantagoasiaticaL)的染色体数目为2n=36,核型公式为K(2n)=36=32m+4sm,核型“1A”型。 相似文献
13.
Lycoris radiata (L′Her. ) Herb. containing wild and cultural types, is distributed
in China and Japan. The karyotype variation in three populations of the species from Anhui
is studied in this paper. (1) Wuhu wild population has a karyotype 2n=21+1B= 1m+12st
+8t+1B. The chromosomes range in length from 7.50 to 14.10 µm with the ratio of the
longest to the shortest 1.88. The karyotype belongs to Stebbins’(1971) 3A. (2) Huangshan wild population has two cytotypes: 2n=22 and 2n=22+1B. Type Ⅰ: The karyotype
formula is 2n=22=12st+10t. The chromosomes range in length from 6.85 to 9.95 µm.
with the ratio of the longest to the shortest 1.45. The karyotype belongs to 4A. Type Ⅱ:
The karyotype formula is 2n=22+1B=6st+14t+2T+1B (plate 1: 7,8). The chromosomes range in length from 6.50 to 11.02 µm. with the ratio of the longest to the shortest
1.70. The karyotype belongs to 4A. (3) Wuhu cultural type has a karyotype 2n=33=30st
+3t. The chromosomes range in length from 7.10 to 9.35 µm with the ratio of the longest
to the shortest 1.32. The karyotype belongs to 4A. This result agrees well with the previous
reports. The diploid types of Lycoris radiata (L´Her.) Herb. are found in Anhui for the firsttime. 相似文献
14.
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 gynaecological 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 provinoes 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 subspecies) 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 consideration, 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
15.
长柄山蚂蝗属Podocarpium(Benth.)Yang et Huang属蝶形花科,间断分布于东亚和中北美洲,广布种分布到非洲和大洋洲。北美有4种,亚洲约有14种.我国约有该属植物11种,以西南和长江以南地区分布种类最多。国外已有人做过本属一半以上的种的染色体记数和核型。本文对本属的三个种.长柄山蚂蝗P.podocarpum(DC.)Yang et Huang,大苞长柄山蚂蝗P.williamsii(Pamp.)Yang et Huang和云南长柄山吗蝗P.du-clouxii(Pamp.)Yang et Huang进行了染色体的记数和核型描述,其中后两个种的工作属于首次。此外,本文还首次报道了山蚂蝗属两个种:Des-modium caudatum(Thunb.)DC.和D.yunnanense Franch.的染色体数目。 相似文献
16.
17.
Cytological studies were carried out for 13 taxa in the genus Iris from China, of which three species, namely I. subdichotoma, I. delavayi and I. cuniculiformis were endemic to China. The chromosome numbers in somatic cells for each taxon were as follows: I. subdichotoma, 2n=42; I. japonica, 2n=34; I. wattii, 2n=30; I. laevigata, 2n=32; I. ruthenica var. nana, 2n=42; I. collettii, 2n=28; I. dolichosiphon and I. cuniculiformis, 2n=22; I. bulleyana, I. delavayi, I. chrysographes, I. forrestii, and I. lactea var. chinensis, 2n=40. The chromosome number and karyotype of I. cuniculiformis were reported here for the first time and its karyotype formula was 2n=22=4m+6sm+12st(2SAT). The karyotype of I. dolichosiphon was also firstly reported, whose karyotype formula was 2n=22=4m+12sm+6st. The chromosome number and karyotype of I. subdichotoma was newly observed, whose karyotype formula was 2n=42=20m+22sm. Three populations of I. ruthenica var. nana from different localities were investigated and all the three populations had the same chromosome numbers different than previously reported. The karyotype formulae for I. ruthenica var. nana were shown as follows: Zhongdian population, 2n=42=30m+12sm (2SAT); Lijiang population, 2n=42=28m+14sm(2SAT); Nixi population, 2n=42=36m+6sm (4SAT). In addition, the 2n chromosome numbers of three subgenera Limniris, Iris and Nepalensis in the genus Iris from present results and previous reports were summarized. The results showed that the chromosome number varied considerably in subgen. Nepalensis, in which I. subdichotoma was possibly a key species between the genus Pardanthopsis and subgen. Nepalensis. Chromosome number of I. ruthenica was reported as 2n=84 which was twice as much as its variety I. ruthenica var. nana (2n=42) we observed. By comparing with related groups, I. ruthenica is likely to derive from diploid group. Finally, variation of chromosome number and evolutional tendency of karyotype in the genus Iris were also discussed. 相似文献
18.
山东四种草本植物的核型研究 总被引:5,自引:2,他引:3
本文对山东4种草本植物进行了染色体研究。结果表明:阿尔泰狗哇花(Heteropappusal taicus(Wild)Navopokr)的染色体数目为2n=36,核型公式为K(2n)=36=36m,核型“1A”型;求米草(Oplismenusundulatifolius(Arduino)RoemetSchult)的染色体数目为2n=12,核型公式为K(2n)=12=8m+4sm,核型“2A”型;红秋葵(Hibiscuscocineus(Medic)Walt)的染色体数目为2n=38,核型公式为K(2n)=38=14m+22sm+2st,核型“2B”型;蟋蟀草(Eleusineindica(L)Gaertn)的染色体数目为2n=18,核型公式为k(2n)=18=16m+2sm,核型“2A”型。 相似文献
19.
安徽石蒜属4种植物核型研究 总被引:15,自引:0,他引:15
本文分析了安徽境内石蒜属LycorisHerb.4种植物的核型,并结合有关文献探讨它们的核型变异。结果表明,乳白石蒜L.albifoliaKoidz.的核型为2n=19=3m+7st+4t+5T,属3B型;中国石蒜L.chinensisTraub.为2n=16=6m+10T,属3B型;石蒜L.radiata(L’Her.)Herb.为2n=22=4st+18t,属4A型;换锦花L.sprengeriComes.exBaker.为2n=22=2st+20t,属4A型。以上各种植物均未发现随体和次缢痕,通过核型比较,可见同种不同居群间在染色体数和核型结构上均存在较大的变异。 相似文献