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1.
The karyological survey of the Spanish taxa of Lithospermeae is completed with studies of OnosmaL., Cerinthe L. And Alkanna Tausch. The chromosome number of O. Tricerosperma Lag.subsp. tricerosperma is reported for the first time and those of C.gymnandra Gasparr. And A. Tinctoria (L.) Tausch have been counted for the first time in Spanish material.
Con este trabajo se completa el estudio cariologico de los taxones espanoles de Lithospermeae. Se estudian los correspondientes a OnosmaL., CerintheL. y Alkanna Tausch, de ellos, el niimero cromosomico de 0. Tricerosperma Lag.subsp. tricerosperma se indica por primera vez y los de C.gymnandra Gasparr.y A. Tinctoria (L.) Tausch corresponden al primer recuento con material espanol.  相似文献   

2.
LUQUE, T., 1992. Karyological studies on Spanish Boraginaceae. VI. Contribution to the tribe Eritrichieae. Karyological information is presented for c. 15 taxa of the genera Asperugo L., Rochelia Reichenb., Myosotis L. and Lappula Gilib. This paper is the first in this series of karyological studies of Spanish Boraginaceae to deal with Eritrichieae.  相似文献   

3.
Fourteen species ofAsarum s. str.,Asiasarum andHeterotropa were studied cytotaxonomically. Their karyotypes and C-banding patterns were examined in detail. The results obtained were different in some important respects from previous reports related to the chromosomes of these plants, and were partially disharmonious with the assumptions presented for the relationships among these genera by some previous workers. Furthermore, it was confirmed thatAsarum s. str. (2n=26) (excludingAsarum leptophyllum),Asiasarum (2n=26),Heterotropa (2n=24) andAsarum leptophyllum (2n=24) are distinct from one another in the karyotype and the C-banding pattern of a few pairs of the small chromosomes in each set. The significance of these small chromosomes in considering the relationships among the plants concerned is discussed.  相似文献   

4.
Twenty-two populations of seven species of Cremanthodium from high altitude regions of western China were observed karyologically. C. ellisii, C. microglossum, C. brunneo-pilosum, C. stenoglossum, C. discoideum and C. lineare all had the same chromosome number of 2 n = 58 whereas C. humile had 2 n = 60. All chromosome numbers of these species are documented here for the first time. The basic number of x = 30 is new for this genus. The karyotypes of all species belong to 2A type according to Stebbins' asymmetry classification of karyotypes. Two basic chromosome numbers, x = 30 and x = 29 in Cremanthodium , correspond exactly to two branching patterns in this genus, sympodial versus monopodial. The systematic and taxonomic statuses of the sympodial species need further study. The karyomorphological data provide no support to the sectional subdivision in Cremanthodium .  相似文献   

5.
The somatic chromosome number and detailed chromosome morphology have been studied in populations of seven species of Ranunculus, namely Ranunculus alpestris L., R.glacialis L., R. Thora L., R.seguieri Vill., R. Aconitifolius L., R.platanifolius L. And R. Acetosellifolius Boiss., from the Iberian Peninsula. Diploid levels have been found for these species in the samples studied. From the karyological data (karyograms, idiograms and asymmetry) relationships between these taxa are discussed.  相似文献   

6.
DIOSDADO. J. C, PASTOR, J. E. & VALDÉS, B. 1993. Contributions to the karyological study of the genus Ranunculus L. subgenus Batrachium (DC.) A. Gray from the Iberian Peninsula. The somatic and gametic chromosome numbers and detailed chromosome morphology are presented for eight taxa of aquatic ranunculi from the Iberian Peninsula. Within the subgenus Batrachium diploid and tetraploid levels have been observed (2 n = 16, 32) the commoner of which is the diploid. From the karyological data relationships have been established between the subgenus Batrachium and subgenus Ranunculus.  相似文献   

7.
Karyological information about Iberian Genista species is limited because of their wide geographical distribution. It is a major factor in the understanding of a genus whose genetic evolution is mostly related to aneuploidy and euploidy. The chromosome numbers of the following taxa have been counted: G. carpetana subsp. carpetana (n = 20), G. cinerascens (n = 12), G. micrantha (n = 18), G. mugronensis subsp. rigidissima (n = 18), G. ramosissima (2n = 48) and G. tinctoria (n = 24). The previously-assumed uniformity of chromosome number (n = 24) for all the subspecies of G. cinerea is supported here by data from subspp. murcica and speciosa. In G. florida, a new chromosome number, n = 23, has been found for both subspecies (florida and polygaliphylla). A discussion of the discrepancies between these data and previous ones is included. A new level of ploidy has been found in G. tuurnefortii subsp. tournefortii (n = 32). The data stress the necessity of obtaining chromosomal information from a number of plants of a taxon before its characteristic number is clear, and indicate that more chromosomal data will help the understanding of the cytological diversity within taxa in Genista.  相似文献   

8.
In ground trees, which are devoid of adventive aerial roots, supplementary conductive elements develop in trunk corrugations, forming distinct units with the large side branches above and their roots below. Unlike most epiphytic jungle figs, which ring the stems of dicotyledonous support trees from the outside, the epiphytic bushes of F. religiosa are not true stranglers. Their roots penetrate inside the stem of the support, eventually splitting it from within. The various factors indispensable for the penetration of the roots are discussed. In Nepal and Thailand, because the survival of F. religiosa trees for hundreds of years, there is an accumulation of very old trees, whose supports have by now disappeared or still persist in the form of broken and dead blocks of wood between the stout fig roots. The characteristics of the tree at the various stages of its development support the hypothesis that F. religiosa must have originated under the specific climatic conditions prevailing in he monsoon tropophilous forests (ix. seasonal forests, hygrophilous in summer and xerophilous in winter) at the foot of the Himalayas.  相似文献   

9.
中国蕨类植物细胞分类学研究概况   总被引:1,自引:0,他引:1  
中国蕨类植物类群十分丰富,由63科230属约2600种组成,其中约有10%的种类为中国特有。迄今为止,中国蕨类植物进行过染色体计数的种类约有395种,仅占中国蕨类植物总数的15%,其中48%为多倍体。本文对中国蕨类植物细胞分类学研究的历史和现状进行了综合评述。文中论述了蕨类植物染色体数目和染色体基数在系统学上的应用以及蕨类植物染色体组型分析、多倍化、无融合生殖、多倍体复合体及网状进化的研究概况。中国20多年的蕨类植物细胞分类学研究表明,蕨类植物的染色体数目、基数、组型分析、多倍化及其繁殖方式对蕨类植物的分类、起源和演化的研究都有重要作用,对种及种复合体的鉴定、科属的划分也有重要的参考价值。并对中国蕨类植物细胞分类学研究提出了一些建议。  相似文献   

10.
The prevalence of Borrelia burgdorferi sensu lato in several tick species was studied over a 2 year period in two ecologically different areas in Spain. One area was an endemic area for Lyme disease, with a number of autochthonous human cases and supported large populations of Ixodes ricinus on cattle and birds; the second area was characterized by the absence of I. ricinus together with the presence of foxes and their associated tick species. While I. ricinus was the main vector of B. burgdoreri in the endemic area (with a mean prevalence of 14% in adults and 51% in nymphs), adults of both Ixodes canisuga and Ixodes hexagonus had high rates of B. burgdorferi prevalence (30 and 28%, respectively) in the zone where I. ricinus was absent. Immatures of Ixodes frontalis were found to be carriers of the spirochete only in those zones where I. ricinus is present, suggesting evidence for reservoir competence in a tick-bird cycle.  相似文献   

11.
KONDO, K. & LAVARACK, P. S., 1984. A cytotaxonomic study of some Australian species of Drosera L. (Droseraceae). Karyomorphological comparisons of 15 species of Australian Drosera are presented along with 11 new chromosome counts. In Australia the genus forms an extensive aneuploid series. The species which have chromosome numbers from n =10 to n = 19 show large chromosomes, while those which have chromosome numbers more than 20 show small chromosomes. Drosera paleacca shows the lowest chromosome number in the genus, 2 n = 10, with 10 large chromosomes, indicating a new basic number, x = 5. The non-staining gap between the chromatids of each chromosome is rather wide and their centromeric region is not seen throughout prophase, prometaphase, and metaphase. The C-banding and silver-staining analyses in Drosera petiolaris chromosomes suggest that Drosera chromosomes could have diffuse centromeres and simplified C-segments. Some taxonomic implications are considered, notably the possible removal of Drosera banksii from Drosera section Ergaleium to Drosera section Lasiocephala and the reduction to synonymy of Drosera section Prolifera .  相似文献   

12.
J. M. EDMONDS, 1984. Pollen morphology of Solanum L. section Solnnum . The pollen morphology of both dried and fresh, fixed material was examined using SEM. The work confirmed thc spheroidal to sub-prolate shape, the tricolporate nature and the granular surface sculpturing, typical of Solanurn pollen, but failed to demonstrate the occurrence of exine patterns which could bc of practical taxonomic use is differentiating the species belonging to the section Solanurn . Quantification of the exine sculpturing, by means of granule density counts, indicated a possible relationship between this feature and the morpho-genetic diversity of certain species.  相似文献   

13.
The present study comprises an analysis of six different scoring schemes and eight different types of analytic methods aiming to investigate the evolution of a continuous character (i.e. corolla tube length) in Lithospermum L. (Boraginaceae). Corolla tube length in the genus is quite variable, ranging from 1 mm to 75 mm, and the length of the corolla tube has implications for pollination biology, such as longer corolla tubes (> 25 mm in length) being pollinated by hummingbirds or moths. In general, the various methods resolve similar ancestral character states; however, different states are reconstructed at nodes in which the descendants greatly differ in corolla tube length. Additionally, it is suggested that all of the variation of a continuous character should be included in analyses, and this may necessitate multiple analyses with different partitions of the data. The various analyses provide evidence that two maximum parsimony methods, linear parsimony and the TNT method, minimize the number of different rates of evolution. In Lithospermum, six origins of corolla tubes > 20 mm in length are resolved, and these origins occurred at two different times periods: (1) in the shadow of hummingbird diversification in North America (approximately 6–8 Mya) and (2) more recently (approximately 1–1.5 MyA). Four substantial decreases in corolla tube length also are reconstructed, and these may be associated with the origin of self‐pollination. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??.  相似文献   

14.
15.
Morphological and life-history variation within and between 23 European populations of the introduced and widespread perennial Solidago canadensis L. sensu lato (Asteraceae) was investigated. The populations differed significantly in all 19 characters measured. Coefficients of variation and intraclass-correlations were high for characters related to growth. Floral characters (involucral height, number of disk florets, number of ray florets), and pubescence of stems and leaves varied considerably among sampled shoots, but their frequency distributions were unimodal and the coefficients of variation low. The first three principal components explained 48% of the variation and formed no dusters among the shoots. Several character means correlated with latitude, indicating clinal variation among the populations. Comparison of variation in floral and leaf characters with data from the native range suggests that S. canadensis s.l. naturalized in Europe belongs to a taxon that is close to S. canadensis var. scabra (Muhl.) Torr. & Gray ( S. altissima L.), despite the reported diploid chromosome number of this taxon in Europe.  相似文献   

16.
Lithospermum (Boraginaceae) includes ca. 60 species and exhibits a wide range of floral, palynological, and vegetative diversity. Phylogenetic analyses based on 10 chloroplast DNA regions and 22 morphological characters were conducted in order to (i) examine evolutionary relationships within Lithospermum and among related genera of Boraginaceae, and (ii) investigate patterns of morphological evolution. Several morphological features, such as long‐funnelform corollas, faucal appendages, reciprocal herkogamy, and evident secondary leaf venation, have evolved multiple times within the genus. In contrast, other morphological features, including the presence of glands and the position and number of pollen pores, are less plastic and tend to characterize larger clades. Some features, including the presence of glands, are interpreted as symplesiomorphic for Lithospermum, while others, such as evident secondary leaf venation, appear to have originated repeatedly. The range of structural diversity that occurs among the species of Lithospermum suggests the potential utility of this genus as a model for integrative studies of evolution, development, and molecular biology.© The Willi Hennig Society 2011.  相似文献   

17.
Vanilla claviculata (W.Wright) Sw. and K barbellata Rchb.f. grow sympatrically in the southwestern part of herto Rico. At three localities in the range of the two species, individuals with flowers that appeared Merent from previously known species were found. To test whether these were hybrids between V. claviculata and V. barbellata , 11 morphological floral characters were recorded at seven populations and allozyme profiles of the three taxa compared. Principal component analysis on the morphological characters gave three distinct groups with minor overlaps. The first component axis reflects variation in overall size of the flowers, while the second component reflects variation in the size of the distal aperture of the labellum. Allozyme data revealed that the putative hybrids have a significant surplus of heterozygotes ( F IS = - 0.65) as expected in a F 1 generation. Both data sets support the hypothesis that the individuals are hybrids, which is further augmented by interspecific pollination experiments between the putative parental species. This is the first case of natural hybridization reported in the genus Vanilla .  相似文献   

18.
Relationships among the morphologically diverse members of Saxifragaceae sensu lato were inferred using 130 18S rDNA sequences. Phylogenetic analyses were conducted using representatives of all 17 subfamilies of Saxifragaceae sensu lato, as well as numerous additional taxa traditionally assigned to subclasses Magnoliidae, Caryophyllidae, Hamamelidae, Dilleniidae, Rosidae, and Asteridae. This analysis indicates that Saxifragaceae should be narrowly defined (Saxifragaceae sensu stricto) to consist of ~30 herbaceous genera. Furthermore, Saxifragaceae s. s. are part of a well-supported clade (referred to herein as Saxifragales) that also comprises lteoideae, Pterostemonoideae, Ribesioideae, Penthoroideae, and Tetracarpaeoideae, all traditional subfamilies of Saxifragaceae sensu lato, as well as Crassulaceae and Haloragaceae (both of subclass Rosidae). Paeoniaceae (Dilleniideae), and Hamamelidaceae, Cercidiphyllaceae, and Daphniphyllaceae (all of Hamamelidae). The remaining subfamilies of Saxifragaceae sensu lato fall outside this clade. Francoa (Francooideae) and Bauera (Baueroideae) are allied, respectively, with the rosid families Greyiaceae and Cunoniaceae. Brexia (Brexioideae), Parnassia (Parnassioideae), and Lepuropetolon (Lepuropetaloideae) appear in a clade with Celastraceae. Representatives of Phyllonomoideae, Eremosynoideae, Hydrangeoideae, Escallonioideae, Montinioideae, and Vahlioideae are related to taxa belonging to an expanded asterid clade (Asteridae sensu lato). The relationships suggested by analysis of 18S rDNA sequences are highly concordant with those suggested by analysis of rbcL sequences. Furthermore, these relationships are also supported in large part by other lines of evidence, including embryology. serology, and iridoid chemistry.  相似文献   

19.
Two new species of Heliotropium L. (Boraginaceae, subfam. Heliotropioideae), growing in sandy loam soils in Jizan, south-west Saudi Arabia, Heliotropium chaudharyanum Al-Turki, Omer & A. Ghafoor and Heliotropium jizanense Al-Turki, Omer & A. Ghafoor, are described and illustrated. The relationships of the new species within the small-flowered Heliotropium europaeum L. species group are discussed. Notes on distribution and habitat are provided, together with a map.  相似文献   

20.
The Bomean species of Lithocarpus B1. section Synaedrys edl.) Barnett (Fagaceae) are discussed in terms of their unifying characteristics, and keys to the species are provided. A novel morphological feature present in the genus, where the seed in the mature fruit is enclosed by a lignified and thickened receptacle, is illustrated. A new species, L palungensis Cannon & Manos, is described. It can be distinguished from L. pulcher (King) Markgr. by its submontane distribution, prominent reflexed cupular spines, present at all stages, and broadly oblong leaves with scattered open fasciculate trichomes on the abaxial surface. Foliar trichome types present within the section are also described. Distinctiveness of fruit wall and receptacle shape, as described by two-dimensional elliptic Fourier transformation, is demonstrated by principal components analysis.  相似文献   

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