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1.
Tomosaburo Yabuno 《Genetica》1970,41(1):311-315
The wildEchinochloa species,E. stagnina, is known to be extremely variable. Strains differing in chromosome number and in some characteristics including growth-form have been recognized in this species.The artificial hybrid between the annual 12-ploid (2n=108;x=9) and the perennial 14-ploid (2n=126;x=9) strains (W662 and 60–10 respectively) by systematists considered to be bothE. stagnina, was examined cytologically. From the cytological evidence, it was pointed out that these two strains are distantly related and that each of them should be treated as a distinct species.  相似文献   

2.
The haploid chromosome number of the South American butterfly Philaethria dido varies from 12 to 88. Eight different numbers have been found in this species complex. The related Ph. pygmalion and Ph. wernickei usually show only n=29, a very frequent number in the Lepidoptera; numbers of n=15 and n=21 for these species need confirmation. The most common chromosome number for Ph. dido is also the highest, n=88, and is found in many parts of northern and central Brazil on the Amazon river and its tributaries, as well as adjacent parts of other countries. The other numbers were observed mainly in northern South America and along the east coast. Two very different numbers were found together in four localities. We did not find specimens with meiotic features suggesting hybridization between individuals with different chromosome numbers. The diverse numbers in Ph. dido may belong to good sibling species, distinguishable externally by very minor characters. Since Ph. dido is a very primitive species in the tribe Heliconiini, dating probably from the early Tertiary, it probably has had many opportunities to undergo divergent chromosome evolution in isolation. Its strong, high flight and broad ecological valence would then permit rapid spreading out and coexistence of different chromosome forms, which in some cases have been noted to show diverse behaviour in the field.Dedicated to Professor Hans Bauer on the occasion of his eightieth birthday  相似文献   

3.
The present communication deals with the observations made on the morphology, reproduction and cytology ofUlothrix zonata (Weber & Mohr)Kütz. in culture. The alga displays a remarkable phenotypic plasticity in nature as well as in culture. The present study provides additional evidence of karyology in support ofLokhorst andVroman's treatment ofU. zonata which merges a number of earlier described species in it. The cytological details and chromosome number (n = 10) determined for the Indian isolates ofU. zonata agree with those ofSarma for the British material.NBRI Research Publication No. 63 (N.S.)  相似文献   

4.
New chromosome numbers for two species from the Senecio nemorensis group: S. dacicus (2n = 40) and S. ucranicus (2n = 40) have been ascertained. The counts for S. germanicus Wallr. subsp. germanicus (2n = 40), S. hercynicus Herborg subsp. hercynicus (2n = 40), S. ovatus (P. Gaertn. et al.) Willd. subsp. ovatus (2n = 40) occurring in the Carpathians are also reported. The study confirmed only the known tetraploid chromosome number for the taxa of this group. The pollen fertility ranged from 82.09 to 92.99% in all examined species and subspecies, including their hybrids.  相似文献   

5.
A cytological analysis of 22 experimental interspecific hybrids withinEpilobium sect.Epilobium, involving 15 taxa, has indicated that the generalized western North AmericaE. obcordatum has the BB chromosome arrangement. This strengthens greatly our earlier contention that BB is the original chromosome arrangement in the section. The very distinctive northwestern North AmericanE. luteum, only species in the section with cream-colored petals, has the CC arrangement, like the members ofHaussknecht'sAlpinae. This chromosome arrangement apparently originated in the North Pacific region in plants that were of normal stature. The North AmericanE. leptocarpum, which closely resembles the Japanese endemicE. fauriei and, like it, forms gemmae in the axils of the upper leaves, also resembles it in having the CC chromosome arrangement. The AsianE. platystigmatosum has a novel chromosome arrangement derived from BB, which we here designate the EE arrangement.  相似文献   

6.
Material of 85 species of Brassica and genera closely related to it was examined cytologically, and the chroiftosome counts are reported. These confirm records published by other workers for 42 species, two contradict earlier records, and 41 counts are believed to be new. Different species with the same chromosome number have been cross-pollinated, and those found to be interfertile have been grouped into cytodemes. For the most part species found to be interfertile have long been regarded as closely akin, but three cases of interfertile intergeneric hybrids are reported. Altogether the material has been classified into 45 cytodemes: 35 diploids with chromosome numbers ranging from n= 7 to n= 13, and 10 derived tetraploids. This enumeration is possibly not exhaustive of the world's genomes closely related to the crop Brassicas and a list is appended of the wild species which need examination before the enumeration might be considered to be complete.  相似文献   

7.
Chromosome numbers are determined from 37 populations attributed to 22 taxa of JapaneseArisaema. Of them, chromosome numbers ofA. limbatum var.conspicuum (2n=26),A. minus (2n=26),A. nambae (2n=28) andA. seppikoense (2n=26) are determined for the first time. New chromosome numbers, 2n=26, are reported forA. aequinoctiale, A. limbatum, A. stenophyllum, A. undulatifolium andA. yoshinagae. Three modes of basic chromosome numbers,x=14,x=13 andx=12, occur in JapaneseArisaema. Precise karyotypic comparisons of 20 taxa reveal that taxa withx=14 andx=13 share 26 major chromosome arms and have an obvious chromosomal relationship. One of two submeta-centric chromosomes inx=13 corresponds to two telo-centric chromosomes inx=14. InA. ternatipartitum with 2n=6x=72, ten out of 12 basic chromosomes are the most similar in size and arm ratio with larger ten chromosomes ofA. ringens among JapaneseArisaema examined. A basic chromosome number ofx=14 is the commonest in the genusArisaema and the remaining basic chromosome numbers,x=13 andx=12, seem to be derived through dysploidal reduction by translocating large segments of major arm of telo-centric chromosome onto other minor arm of telo-centric followed by loss of the remainings including a centromere, and by loss of two telo-centrics fromx=14, respectively. Some systematic problems of JapaneseArisaema are discussed based on new cytological data.Arisaema hatizyoense, A. minus andA. nambae are accepted as independent species.  相似文献   

8.
《Journal of bryology》2013,35(2):343-349
Abstract

The chromosome numbers in the genus Gymnostomiella, G. vernicosa n=13, and in the three members of Bartramiaceae, Anacolia sinensis n=6, Philonotis angustata n=12 and P. revoluta n=6 are reported for the first time. The counts for Physcomitrium cyathicarpum n=52, P. repandum n=52, Bartramia hallerana n=9, B. subpellucida n=6 and Philonotis falcata n=12 are at variance with earlier reports. Intraspecific polyploidy is recorded in Philonotis turnerana with n=6 12. Quadrivalents are observed in Philonotis angustata. A dimorphic bivalent, rare in monoecious bryophytes, is observed in Bartramia hallerana. Unlike that of many moss species, the smallest member of the set is heteromorphic in Bartramidula bartramioides, Philonotis calcarea, P. revoluta and P. turnerana.  相似文献   

9.
Thomas F. Daniel 《Brittonia》2006,58(4):291-300
Meiotic chromosome numbers are reported for 12 species in eight genera of Acanthaceae from Madagascar. Chromosome numbers of 11 species are reported for the first time. Counts inMendoncia (n=19) andNeuracanthus (n=20) are the first for these genera. A new chromosome number (n=30) is reported inJusticia. Systematic implications of the chromosome counts are addressed and basic chromosome numbers for these eight genera of Malagasy Acanthaceae are discussed.  相似文献   

10.
Abstract The karyomorphology of three species in Dipentodon (Dipentodontaceae), Perrottetia (Celastraceae), and Tapiscia (Tapisciaceae), namely Dipentodon sinicus, Perrottetia racemosa, and Tapiscia sinensis, was investigated in the present study. Recent molecular research has discovered close relationships among these three genera, which has led to the establishment of the order Huerteales with Perrottetia being placed in Dipentodontaceae. Herein we report the chromosome numbers of D. sinicus and P. racemosa for the first time, and present their karyotype formulas as 2n= 34 = 22 sm + 12 st (D. sinicus), 2n= 20 = 11 m + 9 sm (P. racemosa), and 2n= 30 = 22 m(2SAT) + 8sm (T. sinensis). Asymmetry of their karyotypes is categorized to be Type 3B in D. sinicus, Type 2A in P. racemosa, and Type 2A in T. sinensis. Each of the species shows special cytological features. Compared with Perrottetia, Dipentodon has a different basic chromosome number, a higher karyotype asymmetry, and different karyomorphology of its interphase nuclei, mitotic prophase, and metaphase. Thus, on the basis of these results, we have reservations regarding the suggestion of placing Dipentodon and Perrottetia together in the family Dipentodontaceae.  相似文献   

11.
Gametic and somatic chromosome numbers of eight Asian species belonging to Asplenium sect. Hymenasplenium were determined. Seven species were observed to have chromosome numbers based on x = 39, and one on x = 38. These chromosome numbers are exceptional in Asplenium which is well known to have chromosomes of n = 36 or multiples thereof. Decisions on the taxonomic status of the species of section Hymenasplenium were facilitated by cytological observations. Systematic recognition of this section is also supported by the peculiarity in the chromosome numbers, and evidence for the addition to the section of several other species is presented.  相似文献   

12.
Dioscorea alata is a polyploid species with several ploidy levels and its basic chromosome number has been considered by most authors to be x = 10. Standard chromosome counting and flow cytometry analysis were used to determine the chromosome number of 110 D. alata accessions of the CIRAD germplasm collection. The results revealed that 76% of accessions have 2n = 40 chromosomes, 7% have 2n = 60 chromosomes and 17% have 2n = 80 chromosomes. Progenies were produced from 2n = 40 types of D. alata and the segregation patterns of six microsatellite markers in four different progenies were analysed. The Bayesian method was used to test for diploid versus tetraploid (allo- and autotetraploid) modes of inheritance. The results provided the genetic evidence to establish the diploidy of plants with 2n = 40 chromosomes and to support the hypothesis that plants with 2n = 40, 60 and 80 chromosomes are diploids, triploids and tetraploids, respectively, and that the basic chromosome number of D. alata is x = 20. The findings obtained in the present study are significant for effective breeding programs, genetic diversity analysis and elucidation of the phylogeny and the species origin of D. alata.  相似文献   

13.
The karyotype of individuals of the species Rhinolophus hipposideros from Spain present a chromosome number of 2n = 54 (NFa = 62). The described karyotype for these specimens is very similar to another previously described in individual from Bulgaria. However, the presence of one additional pair of autosomal acrocentric chromosomes in the Bulgarian karyotype and the differences in X chromosome morphology indicated that we have described a new karyotype variant in this species. In addition, we have analyzed several clones of 1.4 and 1 kb of a PstI repeated DNA sequence from the genome of R. hipposideros. The repeated sequence included a region with high identity with the 5S rDNA genes and flanking regions, with no homology with GenBank sequences. Search for polymerase III regulatory elements demonstrated the presence of type I promoter elements (A-box, Intermediate Element and C-box) in the 5S rDNA region. In addition, upstream regulatory elements, as a D-box and Sp1 binding sequences, were present in flanking regions. All data indicated that the cloned repeated sequences are the functional rDNA genes from this species. Finally, FISH demonstrated the presence of rDNA in nine chromosome pairs, which is surprising as most mammals have only one carrier chromosome pair.  相似文献   

14.
Abstract

Embryological researches in the «Thalictrum» genus. II. Embryology and caryology of «Thalictrum lucidum» L. and «Thalictrum minus» L. ssp. «minus». — In their development the female gametophytes of Thalictrum lucidum L. and Thalictrum minus L. ssp. minus follow the Normal type. In the female gametophytes of these species several types of antipodal cells occurs such as: their considerable enlargement, formation of many antipodals polyploid or polinucleated antipodal cells. In these various types, however, a rapid regression of the antipodals occurs. In T. lucidum some tendency to a disposition of the tetrapolarized type has been verified. The chromosome number has been confirmed to ben 2n=28 in besides, in the pollen development, many cases of regression of the microspores has been verified. The chromosome number has been confirmed to ben 2n=28 in Thalictrum lucidum L., and has been found to ben 2n=14 in Thalictrum minus L. ssp. minus, a new number in this species, which was earlier reported to have 2n=42.  相似文献   

15.
Epidendrum is one of the largest Neotropical genera of Orchidaceae and comprises approximately 1500 species. Only 2.8% of these species have been studied cytologically, demonstrating chromosome numbers ranging from n = 12 in E. fulgens to n = 120 in E. cinnabarinum. The present work evaluated the evolution of the karyotypes of Epidendrum spp. based on data gathered from the literature and from analyses of the karyotypes of 16 Brazilian species (nine previously unpublished). The appearance of one karyotype with n = 12 with one larger chromosome pair in subgenus Amphiglottium appears to have occurred at the beginning of the divergence of this lineage, and x = 12 probably represents the basic number of this subgenus. Epidendrum secundum exhibits wide variation in chromosome numbers, with ten different cytotypes found in 22 Brazilian populations, seven of which were new counts: 2n = 30, 42, 50, 54, 56, 58 and 84. Most lineages of Epidendrum seem to have been secondarily derived from one ancestral stock with x = 20, as is seen in the majority of the present‐day representatives of the genus. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172 , 329–344.  相似文献   

16.
Abstract Cytological characters of four species in Syncalathium (Asteraceae: Lactuceae), a small genus with six identified species endemic to alpine scree of the Sino‐Himalayan region, are surveyed in this report. Three species (Syncalathium pilosum, Syncalathium chrysocephalum, and Syncalathium disciforme) are examined for the first time. Combined with our previous counts, five species have been cytologically investigated from the genus and the results indicated that all species are diploid with the basic somatic chromosome number of x=8. The karyotype asymmetry of Syncalathium souliei is 2A, distinct from the other four species of 1A, and the remaining species are divided into two subgroups with different karyotypes, consistent with their morphological features. The significance of the cytological evolution of Syncalathium is briefly discussed.  相似文献   

17.
Morphological and cytological investigations as well as crossing experiments were carried out withRanunculus seguieri Vill. and 4 species of theRanunculus alpestris L. group (R. alpestris L.,R. traunfellneri Hoppe,R. bilobus Bertol.,R. crenatus Waldst. & Kit.). ForR. seguieri andR. alpestris, localities and distribution are given in addition to extensive diagnoses. A key to the species includes morphological characteristics and distribution data forR. traunfellneri, R. bilobus, andR. crenatus. New diagnostic characters are described. Crossing experiments betweenR. seguieri and the species of theR. alpestris group were unsuccessful. All 5 species have a chromosome number of 2n = 16, the record forR. bilobus is new. There is no statistically significant difference between the karyotypes ofR. seguieri andR. alpestris s. str. Nevertheless, according to morphological evidence and crossing experiments,R. seguieri is not closely related to theR. alpestris group.
  相似文献   

18.
Summary In West Pakistan 17 species of Gymnosperms are found wild. Out of these 13 species belong to the conifers and 4 species are of Ephedra. In the Plains only Ephedra foliata Borss. is found. In the outer ranges of Kashmir, Murree Hills, Hazara, Swat and Dir which are under the dominant influence of summer monsoon rains only Conifers consisting of Pinus roxburgii Sarg. Pinus wallichiana A.B.Jacks., Picea smithiana Boiss., Taxus baccata L., Abies pindrow Spach., Abies spectabis Royle are found and are indigenous to the Western Himalayas with the exception of Taxus baccata L. These species show relationship with those found in the Mediterranean and temperate Central European regions. There is not much resemblance between these and the Conifers of adjoining Eastern Himalayas. The Conifers and the Ephedra species found in Quetta, Waziristan, Kurram, Chitral, Gilgit, Indus Kohistan and Upper parts of Dir, Swat, Kaghan and Kishan Ganga which are under the dominant influence of winter rains are inhibited by elements of Pak-Turanio floristic region. The species belonging to this category are Cedrus deodara Loud., Pinus gerardiana Wall., Juniperus macropoda Boiss., Juniperus communis L., Ephedra gerardiana Wall. and Ephedra intermedia Sabr. et C.A.May. Plants of this region show clear affinities with the flora of the Mediterranean region. In the northern parts like Chitral and Gilgit central Asian elements are represented by Ephedra przewalskii Stapf and Juniperus turkestanica Kom.
Zusammenfassung In West Pakistan gibt es 17 Arten von Gymnospermen, von denen 13 Coniferen und 4 Ephedra sind. Im Flachland gibt es nur Ephedra foliata Boiss. Am äusseren Rande von Kashmir, Murree Hills, Hazara, Swat und Dir, wo der Einfluss der Sommermonsun Regen gross ist findet man Pinus roxburgii Sarg, Pinus wallichiana A.B.Jacks., Picea smithiana Boiss., Taxus baccata L. Abies pindrow Spach. und Abies spectabis Royle. Dies sind einheimische Arten aus West Himalaya mit Ausnahme von Taxus baccata L. Sie haben Verwandtschaft mit den Arten aus der Mediterran und gemässigten Zone Mitteleuropas, aber überhaupt keine mit dem benachbarten östlichen Himalaya Gebiet. Die Coniferen und Ephedra-Arten aus Quetta, Waziristan, Kurram, Chitral, Gilgit, Indus Kohistan, und dem oberen Teil aus Dir, Swat, Kaghan und Kishan Ganga stehen unter dem Einfluss der Winterregen, und bilden das Pak-Turanio floristische Gebiet. Es sind die Arten Cedrus deodara Loud., Pinus gerardiana Wall., Juniperus macropoda Boiss., Juniperus communis L., Ephedra gerardiana Wall., Ephedra intermedia Sabr. et C.A.May. Die Vegetation dieses Gebietes zeigt eindeutige Verwandtschaft mit der Vegetation des Mediterran-Gebietes. In dem nördlichen Teil, wie Chitral und Gilgit sind Ephedra przewalskii Stapf. und Juniperus turkestanica Kom. zentral-asiatische Elemente.
  相似文献   

19.
Abstract Chromosomes in 25 species of Membracidae are recorded. Numbers, size and behaviors of the chromosomes during meiosis and mitosis are used as specific or generic features for the taxonomy of this group. Chromosome numbers vary from n=5 to 12, and sex mechanism are of XO type except two species with neo-XY system. The histogram indicates that 2n=11 with XO sex mechanism is the modal chromosome number, and another type n=10 is also commonly found in this family.  相似文献   

20.
Karyomorphological comparisons were made of five species of JapaneseWoodwardia. There were no marked differences at interphase and prophase among the five species.Woodwardia japonica, W. prolifera, andW. unigemmata were diploid with 2n=68 and the formulas of their metaphase karyotypes uniformly 4m(median centromeric chromosomes)+12sm(submedian)+52(st+t)(subterminal and terminal).Woodwardia orientalis was tetraploid with 2n=136 and 8m+24sm+104(st+t), and the ratio of each chromosomal type to total complement was identical to that of three diploid species. These four species had several characteristics in common:x=34, the longest chromosome of sm, and a mean chromosome length over 3.0 μm. AlthoughWoodwardia orientalis showed some similarity toW. prolifera, it seems to be an allotetraploid which originated by chromosome doubling of a hybrid ofW. prolifera and a diploid species as yet karyomorphologically unknown.Woodwardia kempii was tetraploid with 2n=124 and 8m+24sm+92(st+t), and differed from the others in havingx=31, the longest chromosomes of t, and a mean chromosome length under 3.0 μm. This species has been classified as an independent genus,Chieniopteris, and our karyomorphological study supports this treatment.  相似文献   

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