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1.
We report the isolation and characterization of eight microsatellite loci for Hypochaeris salzmanniana, an endangered species endemic to the southwestern coast of Spain and the Atlantic coast of Morocco. A total of 32 alleles were detected across a sample of 45 individuals, with an average number of 4.0 alleles per locus. The average polymorphic information content (PIC) was 0.533 and the observed (H O) and expected (H E) heterozygosity values varied from 0.022 to 0.978 and from 0.434 to 0.759, respectively. Five loci exhibited significant deviation from Hardy–Weinberg equilibrium (≤ 0.001) and three pairs of loci showed significant linkage disequilibrium (≤ 0.01). The eight loci were tested for transferability in three others species (H. arachnoidea, H. glabra, and H. radicata) belonging to the same section of H. salzmanniana. With the exception of locus Hsalz7, all loci successfully amplified in the three species. These preliminary data confirm the usefulness of microsatellite markers for assessing the ecology and genetic structure of H. salzmanniana and to understand the evolution of species within the section Hypochaeris.  相似文献   

2.
Aim  To analyse phylogeographic patterns in the four species of Hypochaeris sect. Hypochaeris , evaluating possible areas of origin and the microevolutionary processes that have shaped their morphology, genetics and distribution.
Location  Western Mediterranean area.
Methods  We applied amplified fragment length polymorphism (AFLP) markers to a total of 494 individuals belonging to 82 populations of Hypochaeris arachnoidea , H. glabra , H. radicata and H. salzmanniana to determine population structure.
Results  Populations with the largest proportion of private and rare AFLP fragments were found in Morocco. This region was consequently inferred to be the ancestral area for H. arachnoidea , H. glabra , H. radicata and H. salzmanniana . The Guadalquivir River (southern Spain) was inferred to be an effective dispersal barrier for H. glabra and H. radicata. The Strait of Gibraltar was inferred to be a somewhat weaker barrier than the Guadalquivir River for H. radicata and a much weaker barrier for H. glabra . The main barrier for H. salzmanniana coincides with the extension of the Rif Mountains to the Atlantic coast in Morocco, and the Strait of Gibraltar is a much weaker barrier for this species. Hypochaeris arachnoidea appears to have originated in the Atlas Mountains.
Main conclusions  The highest levels of genetic variation in La Mamora forest ( H. glabra and H. salzmanniana ) or the adjacent central Middle Atlas ( H. arachnoidea and H. radicata ) in Morocco suggest that these areas were a centre of origin of Hypochaeris sect. Hypochaeris . All three potential barriers – the Guadalquivir River, the Strait of Gibraltar, and the Rif Mountains – have been important in shaping genetic diversity in species of section Hypochaeris .  相似文献   

3.
In an attempt to delineate the area of origin and migratory expansion of the highly successful invasive weedy species Hypochaeris radicata, we analysed amplified fragment length polymorphisms from samples taken from 44 populations. Population sampling focused on the central and western Mediterranean area, but also included sites from Northern Spain, Western and Central Europe, Southeast Asia and South America. The six primer combinations applied to 213 individuals generated a total of 517 fragments of which 513 (99.2%) were polymorphic. The neighbour-joining tree presented five clusters and these divisions were supported by the results of Bayesian analyses: plants in the Moroccan, Betic Sierras (Southern Spain), and central Mediterranean clusters are all heterocarpic. The north and central Spanish, southwestern Sierra Morena, and Central European, Asian and South American cluster contain both heterocarpic (southwestern Sierra Morena) and homocarpic populations (all other populations). The Doñana cluster includes two homocarpic populations. Analyses of fragment parameters indicate that the oldest populations of H. radicata are located in Morocco and that the species expanded from this area in the Late Quaternary via at least three migratory routes, the earliest of which seems to have been to the southwestern Iberian Peninsula, with subsequent colonizations to the central Mediterranean area and the Betic Sierras. Homocarpic populations originated in the southwestern Iberian Peninsula and subsequently spread across north and central Spain, Central Europe and worldwide, where they became a highly successful weed.  相似文献   

4.
J. S. Parker 《Chromosoma》1975,52(1):89-101
The annual species Hypochoeris glabra (2n = 10) and the perennial H. radicata (2n = 8) hybridise readily in nature and in experiment. During meiosis in F1 hybrids the maximum association is a chain of seven and a bivalent indicating that at least three interchanges differentiate the two genomes. The nucleolar chromosomes in the two species are homologous and form a ring bivalent. They are, however, differentiated since in the F1 hybrid only one nucleolar-organiser region is expressed. Although chromosomal differentiation reduces the egg fertility of F1 hybrids to about 1%, viable backcross hybrids to H. radicata as pollen parent have been experimentally produced and occur in natural populations. Backcrosses with 8, 9 and rarely 13 chromosomes are found and those with 2n = 8 are fully interfertile with H. radicata. Gene flow may therefore take place in natural populations across an aneuploid barrier. The direction of gene flow in Hypochoeris is probably unidirectional from the annual to the perennial.  相似文献   

5.
The species Urtica dioica L., Plantago major ssp. major L., Plantago lanceolata L., Hypochaeris radicata L. ssp. radicata and Hypochaeris radicata ssp. ericetorum Van Soest were grown under high and low nutrient conditions (1/4 Hoagland and 2% of 1/4 Hoagland further called the 100% and 2% treatment, containing 3.75 mM NO-3 and 0.075 mM NO-3, respectively). After a certain period half of the plants were transferred from low to high or high to low nutrients, yielding the 100%/2% and the 2%/100% treatments. The kinetics of nitrate uptake in the range of system I of the five species grown under the different nutrient conditions were measured during a three week experimental period. The nitrate uptake of all the species showed the characteristic features of Michaelis-Menten kinetics. Under low nutrient conditions the apparent Vmax of U. dioica expressed per g dry root was lower than under high nutrient conditions. For H. radicata ssp. radicata and for H. radicata ssp. ericetorum the reverse was found. The Vmax values of P. major ssp. major were almost the same for the two treatments. The apparent Vmax in young plants of P. lanceolata was higher in the 100% treatment than in 2%; whereas the reverse was found in mature plants. The results are explained in relation to the relative growth rate, the shoot to root ratio and the natural environment of the species. The apparent Km values were not influenced by the different treatments. Differences in Km between the species, if any, were very small. It is suggested that the Vmax is a more important parameter for the distribution of plant species in the field than the Km. The rate of nitrogen accumulation was calculated from growth data and the contents of nitrate and reduced nitrogen. It is concluded that the Vmax of system I for nitrate uptake in most cases was sufficient to explain the observed growth rates.  相似文献   

6.
Summary Uptake and assimilation of nitrate by two subspecies ofHypochaeris radicata L. were investigated under laboratory conditions as well as in the field.H. radicata ssp.radicata grows on relatively nitrogen-richer soils thanH. radicata ssp.ericetorum. Attempts were made to relate nitrate uptake and nitrate assimilation in the two subspecies to their different distribution in the field.No differences between the two subspecies with respect to nitrate uptake and nitrate assimilation were observed under laboratory conditions. In plants from the field intact tissue nitrate reductase was higher in ssp.radicata than in ssp.ericetorum. The nitrate reductase activity of both subspecies responded positively to nitrate addition.The significance of nitrate uptake capacity and the level of nitrate reductase for the distribution of plants in the field is here discussed.Grassland species research group, publ. no.15.  相似文献   

7.
During habitat fragmentation, plant populations become smaller and more isolated from each other, resulting in increasing inbreeding rates within populations. Furthermore, fragmentation is often accompanied by a progressive deterioration of soil conditions. Overall, high inbreeding rates and poor soil conditions decrease plant performance and so increase the probability of extinction of fragmented plant populations. The goal of this study was to investigate the effects of inbreeding and soil acidification on seed and offspring traits of Succisa pratensis and Hypochaeris radicata, two plant species differing in mating system, lifespan and dispersal ability. For each species, plants from four populations of different sizes were hand-pollinated. The selfed and outcrossed progeny were grown at two soil pH levels. Overall, results showed that the dispersal potential of H. radicata was reduced by selfing, indicating that dispersal capacity is not independent from the genetic erosion process. Variation among seed families and its interactions with pollination treatments indicate that dispersal capacity may have a genetic basis. The performance of both species decreased sharply as soil conditions became more acidic, but inbreeding did not aggravate the process. These results suggest that S. pratensis and H. radicata populations may decline in the long term; however, family level variation suggests a potential for adaptation to new conditions.  相似文献   

8.
Linaria incarnata has been treated as a widely distributed Ibero‐North African species in the latest taxonomic reviews. Morphological and phylogenetic disparity between populations of this species has been previously reported. Here we present new morphological and phylogenetic evidence for the disintegration of L. incarnata into three distinct species: L. incarnata from the western Iberian Peninsula; L . mamorensis sp. nov. from north‐western Morocco; and L. onubensis from south‐western Spain. The relatively poor morphological differentiation between these taxa (which can be regarded as cryptic species) and their distinct phylogenetic positions indicate that characters of the L. incarnata morphotype have been acquired multiple times in the evolution of Linaria section Versicolores. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 00, 000–000.  相似文献   

9.
We investigated the range dynamics of Artemisia eriantha, a widespread, but rare, mountain plant with a highly disjunct distribution in the European Alpine System. We focused on testing the roles of vicariance and long‐distance dispersal in shaping the current distribution of the species. To this end, we collected AFLP and plastid DNA sequence data for 17 populations covering the entire distributional range of the species. Strong phylogeographical structure was found in both datasets. AFLP data suggested that almost all populations were genetically strongly differentiated, with 58% of the overall genetic variation partitioned among populations. Bayesian clustering identified five groups of populations: Balkans, Pyrenees, Central Apennines, one southwestern Alpine population and a Widespread cluster (eastern Pyrenees, Alps, Carpathians). Major groups were supported by neighbor‐joining and NeighbourNet analyses. Fourteen plastid haplotypes were found constituting five strongly distinct lineages: Alps plus Pyrenees, Apennines, Balkans, southern Carpathians, and a Widespread group (eastern Pyrenees, northern Carpathians, Mt. Olympus). Plastid DNA data suggested that A. eriantha colonized the European Alpine System in a westward direction. Although, in southern Europe, vicariant differentiation among the Iberian, Italian and Balkan Peninsulas predominated, thus highlighting their importance as glacial refugia for alpine species, in temperate mountain ranges, long‐distance dispersal prevailed. This study emphasizes that currently highly disjunct distributions can be shaped by both vicariance and long‐distance dispersal, although their relative importance may be geographically structured along, for instance, latitude, as in A. eriantha. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 214–226.  相似文献   

10.
Summary A method is described for culturing plants at extremely low nutrient concentrations. Using a Braun infusion pump, a fixed amount of nitrate or ammonium was supplied continuously to plants growing in a culture vessel at a rate limiting the uptake of the plants. At a very low nitrogen concentration an equilibrium was established where uptake rate of the plants is equal to the rate of supply by the infusion pump. The nitrogen concentrations reached appeared to be in the order of 1 μM. The method compared the nitrate uptake byHypochaeris radicata L.ssp.radicata, H. radicata ssp.ericetorum Van Soest andUrtica dioica L. and ammonium uptake byH. radicata ssp.radicata andH. radicata ssp.ericetorum. Plants were cultivated in monocultures or in mixed cultures (two species per culture vessel). For the mixed cultures competition for nitrate (or ammonium) between the species was maintained for long periods. The capacities of the uptake systems of two subspecies ofH. radicata from places different in nitrogen supply and pH were adapted equally well to both low nitrate and low ammonium concentrations. Apparently factors other than nitrogen uptake play a part in the distribution of the subspecies. The capacity of the uptake system ofU. dioica, a nitrophilous species, was lower than that ofH. radicata ssp.radicata, a species from places poorer in nitrogen. This difference is related to the different distribution of the two species in the field. The present results are compared with those of previous experiments where Km and Vmax were measured and the significance of both parameters is discussed.  相似文献   

11.
Root respiration of the tap root forming species Hypochaeris radicata L. was measured during tap root formation. A comparison was made of two subspecies: H. radicata L. ssp. radicata L., a subspecies from relatively rich soils, and H. radicata L. ssp. ericetorum Van Soest, a subspecies from poor acidic soils. Root respiration was high and to a large extent inhibited by hydroxamic acid (SHAM) before the start of the tap root formation, indicating a high activity of an alternative non-phosphorylative electron transport chain. The rate of root respiration was much lower and less sensitive to SHAM when a considerable tap root was present. However, root respiration was also cyanide-resistant when a tap root was present, indicating that the alternative pathway was still present. A decreased rate of root respiration coincided with an increase of the content of storage carbohydrates, mainly in the tap root. The level of reducing sugars was constant throughout the experimental period, and it was concluded that the activity of the alternative oxidative pathway was significant in oxidation of sugars that could not be utilized for purposes like energy production, the formation of intermediates for growth or for storage. Root respiration decreased after the formation of a tap root. This decrease could neither be attributed to a gradual disappearance of the alternative chain, nor to a decreased level of reducing sugars. No differences in respiratory metabolism between the two subspecies have been observed, suggesting that a high activity of the alternative oxidative pathway is not significant in adaptation of the present two subspecies to relatively nutrient-rich or poor soils.  相似文献   

12.
Summary The present paper is part of a series of papers comparing two ecologically distinct subspecies ofHypochaeris radicata L.Hypochaeris radicata ssp.radicata grows in more fertile soils thanH. radicata ssp.ericetorum.The dry-weight yield of plants grown from seeds was measured after a 25 days culture period on varying levels of nitrate. Roots and shoots were analyzed for total organic nitrogen and free nitrate. Dry-weight yield showed an almost identical response over the whole range of nitrate concentrations used. The chemical analysis did not reveal differences between the subspecies that could explain the distribution in the field. In a second experiment the growth rate of the two subspecies was measured under optimal nitrate supply during a two month period. Both subspecies exhibited initially the same relative growth rate but one month after sowing the growth rate of both subspecies declined, with a sharper decline in ssp.ericetorum resulting in an 82 per cent difference in dry-weight between both subspecies two months after sowing. Some pronounced formative differences became evident. Shoot to root ratio of ssp.ericetorum showed little response to increasing nitrate concentrations whereas ssp.radicata was clearly responsive in this respect.The contribution of the tap root in total plant dry-weight was relatively higher in ssp.Ericetorum. The decline in growth rate and the formative differences can explain the absence of ssp.ericetorum from nutrient rich soils. when grown on ammonium ssp.radicata had a slightly but not significantly higher yield than ssp.ericetorum. The difference was even greater at low pH. It is concluded that both subspecies are adapted to ammonium nutrition at pH 4.5 as well as at pH 6 and that the absence of ssp.radicata from acidic soils cannot be explained by the low pH. The possibility that both subspecies have different abilities to reduce their growth when nitrate resources become limiting, and yet remain capable for further growth and reproduction is discussed.Grassland species research group, publ. no.16.  相似文献   

13.
In this study, three multiplex PCR panels involving twelve microsatellite loci were developed for cross-species amplification in bighead carp (Hypophthalmichthys nobilis) and silver carp (H. molitrix). The panels were verified using population genetic analyses, and species and simulated hybrid discriminations based on the genotype data of all individuals from two populations for each species. The number of alleles (Na), the observed and expected heterozygosity (Ho and He), and the polymorphic information content (PIC) of twelve loci were ranged from 5 to 20, 0.189 to 0.956, 0.177 to 901, and 0.169 to 0.887, respectively. Overall, almost all the microsatellite loci were detected as highly polymorphic across the two species. The populations of same species showed close genetic distances and similar genetic structures. Significant genetic differentiations were only detected between populations from different species, with a higher variation between species (21.17%) compared with that between populations within species (0.18%). In the species and simulated hybrid discrimination analyses, the individuals from different species were separated distinctly, and the simulated hybrids could almost be separated with the true individuals. In brief, the results indicated the high efficiency of the microsatellite multiplex panels developed in this study, which provide a practicable tool for further genetic analyses of H. nobilis and H. molitrix.  相似文献   

14.
We developed five microsatellites from Ulmus minor using an AFLP protocol followed by an enrichment step, with biotinylated primers containing tandem repeats. Loci were characterized using a total of 30 elms from six Spanish populations. Three microsatellites were also transferred to U. laevis and U. glabra.  相似文献   

15.
Facilitation (positive inter-specific interaction) plays an important role in promoting succession in harsh environments. To examine whether tussocks facilitate the establishment of other species, after peat mining, investigations were carried out in a formerly Sphagnum-dominated wetland (Sarobetsu mire, northern Japan). Two tussock-forming species, Carex middendorffii and Eriophorum vaginatum, have established in sparsely vegetated areas, with a dry ground surface, since peat extraction ended. The following factors were examined, in three microhabitats created by tussocks (center = raised tussock center, edge = tussock edge covered with litter, and flat = flat areas without tussocks): (1) relationships between tussock microhabitats and plant distributions, and (2) the effects of tussocks on survival, growth, flowering and seed immigration of common species. Two (1 × 10 m) plots were established, in each of three sparsely vegetated sites, in September 2005. Tussocks were mapped in each plot, and species, location, flowering, growth stage (seedling, juvenile and fertile) and size of all plants were recorded, during snow-free periods from September 2005 to September 2006. Seed traps were used to investigate seed dispersal from June to October 2006. Four native species, Drosera rotundifolia, Lobelia sessilifolia, Moliniopsis japonica, Solidago virgaurea, and an exotic species, Hypochaeris radicata, were most common. During seedling and juvenile stages, these species were distributed more densely at the tussock edge than in the flat areas, but were less common at the center. H. radicata had a higher survival rate at the edge than in the flat during the winter. The annual growth of H. radicata, L. sessilifolia and S. virgaurea was higher at the edge. Seed traps detected that D. rotundifolia seeds accumulate more at the edge. In conclusion, tussocks facilitated plant establishment in the edge microhabitat by providing litter cover, enhancing seed accumulation, germination and survival, and thus promoted revegetation. However, Sphagnum mosses have not established in the study sites, and the vegetation differs strongly from the areas where no peat mining had taken place.  相似文献   

16.
Early detection of the spatial expansion pattern of alien plants and the associated environmental factors are essential for their management. In this study, we applied regression kriging and geographically weighted regression, which can incorporate spatial autocorrelation into the model, to estimate the critical environmental factors related to the invasion of Hypochaeris radicata into new habitats. We spatially interpolated the occurrence probabilities of H. radicata based on field survey data from 2000–2001 and 2018–2020 to compare the distribution pattern of this species over 20 years. Further, we evaluated the relative importance of environmental variables for the invasion of H. radicata using geographically weighted regression. Based on the results of our model, the expansion of H. radicata was found to be significantly associated with anthropogenic activities, such as human footprinting (HFP) and residential area, and the transportation system area. These results suggest that the primary dispersal forces of H. radicata are human activities, and that roads may be the main corridor of its expansion. Additionally, H. radicata did not invade the forest area over the 20 years. We can predict that this plant may flourish better around big cities because of human activities. Furthermore, deforestation and sporadic mowing can accelerate the expansion of H. radicata because of its preference for sunny spots.  相似文献   

17.
Two species of palo santo trees are distributed in the Galápagos archipelago, the native Bursera graveolens and the endemic Bursera malacophylla (Burseraceae). However, a zone of individuals morphologically intermediate between the two exists on northern Santa Cruz Island and south‐eastern Santiago Island, suggesting that they may not be reproductively isolated. Here we review the species' distributional and morphological differences and test for evidence of hybridization between the two species using DNA sequence and AFLP data. We find that the species lack distinguishing synapomorphies across the five nuclear and plastid regions examined. Population assignment tests and population genetic analyses of AFLP data indicate that genetically similar palo santo individuals (N = 87), including putative hybrids, partition into two genealogical groups that do not uniformly correspond to island‐ or taxon‐based membership. Furthermore, genotypic admixture levels among morphologically intermediate individuals do not indicate widespread hybridization. Thus, we recommend recognizing the endemic palo santo taxon as B. graveolens subspecies malacophylla (B.L.Rob.) A. Weeks & Tye comb. & stat. nov. in light of its close genetic relationship to B. graveolens subsp. graveolens and its distinctive morphology and distribution. Future research should quantify phenotypic variation in palo santo populations as another means for understanding the basis of morphological differences between the subspecies. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 396–410.  相似文献   

18.
Iberian gypsum outcrops are highly fragmented and ecologically challenging environments for plant colonization. As gypsophytes occur exclusively in such habitats, they are ideal models for the study of both the effects of habitat fragmentation and selection on population genetic diversity and structure. In this study, we used amplified fragment length polymorphism (AFLP) and plastid DNA sequences to investigate the phylogeographical history of the Iberian plant Gypsophila struthium (Caryophyllaceae), a widespread endemic restricted to Iberian gypsum outcrops. Gypsophila struthium consists of two subspecies that differ in the architecture of their inflorescence and have mostly allopatric ranges. Gypsophila struthium subsp. struthium occurs in central, eastern and south‐eastern Iberia, whereas G. struthium subsp. hispanica occurs in northern and eastern areas. AFLPs revealed low but significant genetic differentiation between the subspecies, probably as a result of a recent diversification during the Pliocene–Pleistocene. In the geographical contact zone between the taxa, the Bayesian analyses revealed populations with mixed ancestries and genetic clusters predominantly of one or the other subspecies, indicating incomplete reproductive barriers between them. Plastid DNA haplotypes revealed strong geographical structure and testified to processes of isolation by distance and continuous range expansion for some haplotype clades. The Bayesian analyses of the population structure of AFLP data and nested clade phylogeographical analysis (NCPA) of plastid haplotypes revealed that the putative ancestral range corresponded to central and eastern populations of G. struthium subsp. struthium, with those lineages contributing through more recent expansion to increased genetic diversity and structure of the south‐eastern and eastern ranges of this subspecies and to the diversification of G. struthium subsp. hispanica in northern and eastern gypsum outcrops. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 654–675.  相似文献   

19.
A genetic analysis of freshwater pearl mussel Margaritifera margaritifera populations from NW Spain, a peripheral area of its European distribution, was carried out using microsatellite markers. These populations were formerly reported as genetically differentiated on the basis of growth and longevity studies. Ten loci previously characterized in populations from central Europe were used to comparatively analyze the genetic variability at the southern edge of the species’ range. Iberian pearl mussel populations showed very low genetic variability and significant high genetic differentiation. Half of the total genetic diversity observed appeared to be distributed between populations, which suggested a highly structured adaptive potential in pearl mussel at the southern peripheral distribution of the species. Population distinctiveness was evidenced by assignment tests, which revealed a high accuracy of individual assignments to their population of origin. All data suggested low effective population size and major effects of genetic drift on population genetic structure. In order to avoid further loss of genetic variation in biologically distinctive populations from NW Spain, prioritization of genetic resources of this species is required for conservation and management.  相似文献   

20.
We used Amplified Fragment Length Polymorphism markers (AFLP) and breeding system studies to investigate the population structure and reproductive biology of Hypochaeris angustifolia (Asteraceae: Cichorieae). This species is endemic to altiplanos of the Atlas Mountains (Morocco) where it occurs in scattered populations, and it is the sister species to c. 40 species of this genus in South America. PCoA, NJ, and Bayesian clustering, revealed that the populations are very isolated whilst AFLP parameters show that almost all populations have marked genetic divergence. We contend that these features are more in accord with a vicariance origin for the scattered populations of H. angustifolia, rather than establishment by long-distance dispersal. The breeding system studies revealed that H. angustifolia is a self-incompatible species, with low fecundity in natural and in experimental crosses, probably due to a low frequency of compatible phenotypes within and between the populations.  相似文献   

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