首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 485 毫秒
1.
The present paper reconstructs the biogeographic diversification for Nolana L.f. (Solanaceae), a genus of 89 endemic species largely restricted to fog-dependent desert lomas formations of coastal Peru and Chile. Previous efforts have reconstructed a phylogenetic estimate for Nolana using a combination of molecular markers. Herein, we expand on those results to examine hypotheses of biogeographic origins and diversification patterns. Nolana occupies habitats within a continuous coastal desert and forms a terrestrial archipelago of discrete "islands" unique in size, topography, and species composition. Each locality contains at least one Nolana species and many contain multiple species in sympatry. The genus has a Chilean origin, with the basal clades confined to Chile with wide geographic and ecological distributions. Peru contains two strongly supported clades, suggesting two introductions with subsequent radiation. A Chilean clade of shrubby, small-flowered species appears to have had its origins from the same ancestors of the second line that radiated in Peru and northern Chile. Nolana galapagensis is endemic to the Islas Galapagos, with origins traced to Peruvian taxa with a divergence time of 0.35 mya. Rates of diversification over the past 4.02 mya in Nolana, in one of the driest habitats on Earth, suggest rapid adaptive radiation in several clades. Success in Nolana may be attributed to characters that confer a competitive advantage in unpredictable and water-dependent environments, such as succulent leaf anatomy and ecophysiology, and the reproductive mericarp unique to Nolana. The processes affecting or shaping the biota of western South America are discussed.  相似文献   

2.
The phylogeny of Nolana (Solanaceae), a genus primarily distributed in the coastal Atacama and Peruvian deserts with a few species in the Andes and one species endemic to the Galápagos Islands, was reconstructed using sequences of four plastid regions (ndhF, psbA-trnH, rps16-trnK and trnC-psbM) and the nuclear LEAFY second intron. The monophyly of Nolana was strongly supported by all molecular data. The LEAFY data suggested that the Chilean species, including Nolana sessiliflora, the N. acuminata group and at least some members of the Alona group, are basally diverged, supporting the Chilean origin of the genus. Three well-supported clades in the LEAFY tree were corroborated by the SINE (short interspersed elements) or SINE-like insertions. Taxa from Peru are grouped roughly into two clades. Nolana galapagensis from the Galápagos Island is most likely to have derived from a Peruvian ancestor. The monophyly of the morphologically well-diagnosed Nolana acuminata group (N. acuminata, N. baccata, N. paradoxa, N. parviflora, N. pterocarpa, N. rupicola and N. elegans) was supported by both plastid and LEAFY data. Incongruence between the plastid and the LEAFY data was detected concerning primarily the positions of N. sessiliflora, N. galapagensis, taxa of the Alona group and the two Peruvian clades. Such incongruence may be due to reticulate evolution or in some cases lineage sorting of plastid DNA. Incongruence between our previous GBSSI trees and the plastid-LEAFY trees was also detected concerning two well-supported major clades in the GBSSI tree. Duplication of the GBSSI gene may have contributed to this incongruence.  相似文献   

3.
Fog oases in western South America (locally named lomas) are distributed in a kind of fragmented or patchy way into the coastal desert. Their origin, as well as their current ecological connections in terms of species' dispersal capability, remains an open question. We analyzed the latitudinal pattern in plant species and phylogenetic similarities of 13 lomas, which cover the latitudinal extent of these habitats, from 7°58′ to 26°15′ S. A data-set of 1004 species from available checklists was considered. Plant species composition and phylogenetic relationships among lomas were analyzed by non-metric multidimensional scaling. Our results show three main groups of lomas (northern Peruvian, southern Peruvian, and North-Central Chilean lomas) that are aligned along a complex, nonlinear north–south gradient in ordination space. The weak species overlap between Peruvian and Chilean lomas, together with the higher content in endemic species of the Chilean communities, supports the hypothesis that, at least recently, species composition of the three main groups of lomas has been shaped by desert barriers limiting plant dispersal.  相似文献   

4.
Herbaceous lomas in the Peruvian coastal desert, of South America establish in spring, and its habitat is limited to the southern or southwestern slopes along the coast that are affected by thick fog. The time of appearance, the duration and the thickness of the fog vary greatly from year to year, so the lomas can grow only in habitats with enough water to, sustain seed germination and plant growth. This paper studies the species composition and density of the buried seed population, of the herbaceous lomas of Loma Ancon in order to clarify the mechanisms of the lomas' establishment. The mean number of species with viable seeds was about, 12 spp. m−2 and that of dead seeds was about 22 spp. m−2. The dominant species wereSolanum tuberiferum, S. pinnatifidum andNolana humifusa, both in viable and dead seeds. Viable seed density was about 5000–8000 seeds m−2, which is comparable with the seed densities of other herbaceous communities. Dead seed density was about 15000–27000 seeds m−2, or nearly three times the viable seed density, because the rate of decomposition was slow in the extremely dry conditions. The net increase of viable seeds by seed production was estimated at about 5000 seeds m−2 in 1980, and the increase in the number of dead seeds was 2200 seeds m−2.  相似文献   

5.
Palaua (Malveae, Malvaceae) comprises 15 species endemic to the hyperarid coastal desert of Chile and Peru. So far, chromosome counts have been known for two diploid species (2n = 2x = 10) only. Here we report new chromosome numbers for 12 species of Palaua and four of its sister group Fuertesimalva. Karyotypes including 4',6'-diamidino-2-phenylindole dihydrochloride (DAPI)/chromomycin (CMA3) fluorescent banding are presented for selected species representative of each of the main clades of Palaua. An important finding is the discovery of polyploids in one exclusively tetraploid species (P. Trisepald) and four species with mixed diploid and tetraploid cytorypes (P. Dissecta, P. Mollendoensis, P. Moschata, and P. Tomentosa). The diploid and tetraploid karyotypes are all unimodal, symmetrical and show one or two pairs of satellite chromosomes with their associated CMA+/DAPI-band depending on the cytotype. For some of the tetraploids an autopolyploid origin is suggested.  相似文献   

6.
Palaua(Malveae,Malvaceae)comprises 15 species endemic to the hyperarid coastal desert of Chile and Peru.So far,chromosome counts have been known for two diploid species(2n=2x=10)only.Here we report new chromosome numbers for 12 species of Palaua and four of its sister group Fuertesimalva.Karyotypes including 4,6-diamidino-2-phenylindole dihydrochloride(DAPI)/chromomycin(CMA3)fluorescent banding are presented for selected species representative of each of the main clades of Palaua.An important finding is the discovery of polyploids in one exclusively tetraploid species(P.trisepala)and four species with mixed diploid and tetraploid cytotypes(P.dissecta,P.mollendoensis,P.moschata,and P.tomentosa).The diploid and tetraploid karyotypes are all unimodal,symmetrical and show one or two pairs of satellite chromosomes with their associated CMA+/DAPI- band depending on the cytotype.For some of the tetraploids an autopolyploid origin is suggested.  相似文献   

7.
8.
Chaudhry MS  Batool Z  Khan AG 《Mycorrhiza》2005,15(8):606-611
Plant species dominance and arbuscular mycorrhizas (AMs) were evaluated in four different habitats of Cholistan desert, Pakistan. The sites were selected on the basis of variations in topography, floristic composition and biotic interference. The phytosociological data revealed obvious differences in the floristic composition, plant species diversity, AM colonization and arbuscular mycorrhizal fungi (AMF) spore densities in the rhizospheres. The vegetation pattern and composition was governed by topography and edaphic characteristics of a particular site. Grasses were dominant and main components of vegetation at all the study sites and were invariably mycorrhizal. Some plant species were mycorrhizal at one site but non-mycorrhizal at the other. The AMF survey reported here offers an important starting point from which to analyse AMF community structure in different phytosociological habitats and land uses of Cholistan desert.  相似文献   

9.
The use of natural dyes to color textiles and other objects has a long history in Andean South America, but has for the most part become a lost technology with the introduction of synthetic dyes. A literature and field survey to recover information about the traditional use of dye plants in Peru, from pre-Hispanic to recent times, was accompanied by taxonomic identification of collected dye plant materials. Fiftysix dye plants from Peruvian sources are listed.  相似文献   

10.
Indigenous palm species of Peru are listed with data on their distribution patterns, ecology, frequency, density in the ecosystems, and conservation status. Peruvian palm flora includes 140 native species in 34 genera with the following distribution patterns: strictly Andean (17), Andean and Subandean (3), strictly Subandean (19), Subandean and Amazonian (20), strictly Amazonian (78), Amazonian and South peripheral (2), South peripheral (1). About 43% of the species occur at very low or low frequency in the country and about 9% are insufficiently known in situ for their conservation status to be defined. There are no Extinct species. Sixteen of the 17 strictly Andean palms are threatened species; 3 of them are Endangered, while only 5 strictly Subandean, 3 Subandean-Amazonian, and 4 strictly Amazonian palms are in these categories.  相似文献   

11.
12.

Background

In the Peruvian Coastal Desert, an archipelago of fog oases, locally called lomas, are centers of biodiversity and of past human activity. Fog interception by a tree canopy, dominated by the legume tree tara (Caesalpinia spinosa), enables the occurrence in the Atiquipa lomas (southern Peru) of an environmental island with a diverse flora and high productivity. Although this forest provides essential services to the local population, it has suffered 90% anthropogenic reduction in area. Restoration efforts are now getting under way, including discussion as to the most appropriate reference ecosystem to use.

Methodology/Principal Findings

Genetic diversity of tara was studied in the Atiquipa population and over a wide geographical and ecological range. Neither exclusive plastid haplotypes to loma formations nor clear geographical structuring of the genetic diversity was found. Photosynthetic performance and growth of seedlings naturally recruited in remnant patches of loma forest were compared with those of seedlings recruited or planted in the adjacent deforested area. Despite the greater water and nitrogen availability under tree canopy, growth of forest seedlings did not differ from that of those recruited into the deforested area, and was lower than that of planted seedlings. Tara seedlings exhibited tight stomatal control of photosynthesis, and a structural photoprotection by leaflet closure. These drought-avoiding mechanisms did not optimize seedling performance under the conditions produced by forest interception of fog moisture.

Conclusions/Significance

Both weak geographic partitioning of genetic variation and lack of physiological specialization of seedlings to the forest water regime strongly suggest that tara was introduced to lomas by humans. Therefore, the most diverse fragment of lomas is the result of landscape management and resource use by pre-Columbian cultures. We argue that an appropriate reference ecosystem for ecological restoration of lomas should include sustainable agroforestry practices that emulate the outcomes of ancient uses.  相似文献   

13.
Indigenous Peruvians have used totora (Schoenoplectus californicus: Cyperaceae) vessels or caballitos for fishing along the coast of Peru since pre-Inca times. Presently, caballito use and construction are declining in numerous fishing towns. Participant observation techniques were employed to investigate aspects of caballito construction. S. californicus stems were used to make four bundles to serve as the caballito body. The bundles were lashed together with single and double twist rope made from Furcraea andina (Agavaceae) leaves. The stem of Guadua angustifolia (Poaceae) was used as a paddle for the vessel. Caballito construction has varied little through time. We documented a decline in the use of traditional plant materials due to their scarcity. Huanchaco fishermen have played an important role in maintaining the tradition of building caballitos.  相似文献   

14.
Our goal was to investigate in more detail wild and cultivated common bean (Phaseolus vulgaris) accessions from northwestern South America (Colombia, Ecuador, and northern Peru) because prior research had shown this region to be the meeting place of the two major gene pools (Middle American and Andean) of common bean. Explorations were conducted in these countries to collect additional materials not represented in germplasm collections. It was possible to identify wild common bean populations in Ecuador and northern Peru, where they had never been described before. In addition, we were able to extend the distribution of wild common bean in Colombia beyond what was known prior to this study. In all areas, the wild common bean habitat had suffered severely from destruction of natural vegetation. In Colombia, wild common beans were found on the Eastern slope of the Andes (in continuation of its distribution in Venezuela), whereas in Ecuador and northern Peru they were found on the western slope of this mountain range. This geographic distribution was correlated with an ecological distribution in relatively dry environments with intermediate temperatures (known as “dry mountain forest”). Isozyme andphaseolin seed protein analyses of the northern Peruvian and Ecuadoran wild populations showed that they were intermediate between the Middle American and Andean gene pools of the species. Phaseolin analyses conducted on landraces of the Upper Magdalena Valley in Colombia showed that Andean domesticates were grown at a higher altitude than Middle American domesticates suggesting that the former are adapted to cooler temperatures. Our observations and results have the following consequences for the understanding and conservation of genetic diversity in common bean and other crops: 1) Our understanding of the distribution of the wild relative of common bean (and other crops) is imperfect and further explorations are needed to more precisely identify and rescue wild ancestral populations; 2) For crops for which the wild ancestor has not yet been identified, it may be worthwhile to conduct additional explorations in conjunction with genetic diversity studies at the molecular level to guide the explorations; 3) Our study shows the benefit for more efficient germplasm conservation which can be derived from the dynamic interplay between field explorations (and other conservation operations) and molecular analyses to determine genetic distances and diversities; 4) The intermediate materials identified in northern Peru and Ecuador may have basic importance to understand the origin of the common bean and an applied role as a bridge between the Middle American and Andean gene pools; and 5) The differential adaptation to temperature of the two major cultivated gene pools may help breeders select genotypes based at least partially on their evolutionary origin.  相似文献   

15.
Observations among former American residents living long-term in Peru suggested that hair health improved while in Peru. To determine if a Peruvian diet correlates with hair composition, dietary intake of nutrients and mineral content of hair were measured among Peruvian and matched US residents. Selected foods from Peru were also analyzed for mineral and antioxidant content and compared with equivalent foods available in the USA. Statistically significant differences between Peruvian and US residents’ hair were found for sodium (decreased in Peru, p?=?0.007) and vanadium (decreased in Peru, p?=?0.03). Differences in hair composition between residencies may be explained by lower dietary sodium and vanadium intake among Peruvian residents or by lower concentrations of these minerals in Peruvian drinking water. Many significant mineral differences were also identified between Peruvian foods and their US equivalents. Although no statistically significant correlations between dietary intake and hair mineral content were found, results indicate that a Peruvian diet contributes differently to hair composition than a US diet. More research is needed to elucidate the link between a Peruvian diet and specific aspects of hair health.  相似文献   

16.
A phytosociological survey of seacliff and headland vegetation on the central and south coast of New South Wales was carried out. Analysis of the quadrat data led to the recognition of 15 communities; the occurrence of a number of other vegetation types is briefly discussed. The vegetation types fall into three major groupings: grasslands, scrub and heathland, although the coincidence between structural and floristic boundaries is poor. Ordination of the communities indicates that the major factors varying between communities are exposure and soil fertility, the grasslands and scrubs occurring on more fertile soils than the heathlands. Amongst the woody communities it is suggested that the two major groups recognized fall into different phytosociological alliances, although lack of studies of Australian vegetation limits the applicability of a conventional hierarchical classification. The true heathlands correspond closely with the alliance Leptospermion, previously recognized in Victoria. The scrub communities are assigned to a new alliance, the Westringio-Banksion integrifoliae.  相似文献   

17.
The dynamics of dissemination of the environmental human pathogen Vibrio parahaemolyticus are uncertain. The O3:K6 clone was restricted to Asia until its detection along the Peruvian coasts and in northern Chile in 1997 in phase with the arrival of El Niño waters. A subsequent emergence of O3:K6 strains was detected in austral Chile in 2004. The origin of these 1997 and 2004 population radiations has not yet been conclusively determined. Multiple loci VNTR analysis using seven polymorphic loci was carried out with a number of representative strains from Asia, Peru and Chile to determine their genetic characteristics and population structure. Asian and Chilean subpopulations were the most genetically distant groups with an intermediate subpopulation in Peru. Population structure inferred from a minimum‐spanning tree and Bayesian analysis divided the populations into two genetically distinct groups, consistent with the epidemic dynamics of the O3:K6 clone in South America. One group comprised strains from the original Asiatic population and strains arriving in Peru and Chile in 1997. The second group included the remaining Peruvian Strains and Chilean strains obtained from Puerto Montt in 2004. The analysis of the arrival of the O3:K6 clone at the Pacific coasts of South America has provided novel insights linking the origin of the invasion in 1997 to Asian populations and describing the successful establishment of the O3:K6 populations, first in Peru and subsequently in the South of Chile owing to a possible radiation of Peruvian populations.  相似文献   

18.
Natural and semi-natural plant communities of Svjatoj Nos Peninsula on the East coast of Lake Baikal, Eastern Siberia, Russia, are classified and described using the methods of Braun-Blanquet phytosociology. A total of 48 associations and communities were recognized, comprising alpine tundra, subalpine forb vegetation, aquatic macrophyte vegetation, tall-herb and poor fens, mires, bogs, meadows, sand-dune and steppe vegetation. Twenty six syntaxa of ranks ranging from subassociation to class are described or validated for the first time. All communities are documented by phytosociological relevés.  相似文献   

19.
The monophyletic Morpho sulkowskyi butterfly group, endemic of Andean cloud forests, was studied to test the respective contributions of Mio‐Pliocene intense uplift period and Pleistocene glacial cycles on Andean biodiversity. We sampled nine taxa covering the whole geographical range of the group. Two mitochondrial and two nuclear genes were analysed using a Bayesian method. We established a dated phylogeny of the group using a relaxed clock method and a wide‐outgroup approach. To discriminate between two hypotheses, we used a biogeographical probabilistic method. Results suggest that the ancestor of the M. sulkowskyi group originated during the Middle–Late Miocene uplift of the Eastern Cordillera in northern Peru. Biogeographical inference suggests that the Msulkowskyi and Morpho lympharis clades diverged in the northern Peruvian Andes. The subsequent divergences, from the Late Miocene to the Late Pliocene, should have resulted from a dispersal towards the Northern Andes (M. sulkowskyi clade), after the closure of the West Andean Portal separating the Central and Northern Andes, and a southwards dispersal along the Peruvian and Bolivian Eastern Cordilleras (M. lympharis clade). Only a few divergences occurred at the very end of the Pliocene or during the Pleistocene, a period when the more recent uplifts interfered with Pleistocene glacial cycles.  相似文献   

20.
Studies of geographic distribution and physiological adaptations in theBromeliaceae of coastal Chile and Peru provide insights into the ecological patterns of habit selection and speciation. The hyperarid coastal Atacama and Peruvian Deserts along the Pacific coast of South America contain a surprisingly rich flora of bromeliad species. These include representatives of all threeBromeliaceae subfamilies: two terrestrialBromelioideae and two terrestialPitcairnioideae, all with rooted growth morphologies, and 14 species ofTillandsioideae (allTillandsia) with epiphytic and unrooted, terrestraial representatives. TheBromelioideae are represented by two species ofPuya Molina, one each in Peru and Chile. ThePitcairnioideae are represented by two genera,Deuterocohnia andPitcairnia, with one species each. The 14Tillandsia species are distributed in five subgenera which have successfully invaded the coastal deserts, and include both widespread and local endemics with xeromorphic adaptations. All theTillandsia species are epiphytic in the broad sense, but in addition to growing on plants, they are found growing on rocks (i.e. saxicolous or epilithic). Six species (T. purpurea, T. latifolia, T. capillaris, T. marconae, T. werdermanii, andT. landbeckii) have evolved a highly specialized substrate ecology where they grow essentially unrooted on sand (i.e. epiarenic). Nowhere in the world are bromeliads more dominant or have more biomass than in these coastal species growing on sand. Many of these species grow at the absolute limits of vascular plant tolerance, with the entire community consisting of a singleTillandsia species. Rooted, terrestrial bromeliads in the coastal lomas formations (allPitcairnioideae) include CAM, C3, and C3-CAM flexible taxa in their metabolic systems, the CAM species growing in the most arid sites along the coast and C3 species growing in the most mesic habitats within the center of the coastal fog belt where fog moisture input is highest. All of the epiphyticTillandsia species of the coastal desert region utilize CAM metabolism entirely or in part. At least two species,T. latifolia andT. tragophoba, utilize a flexible C3-CAM mode of carbon fixation. Whereas most of the desert-inhabitingTillandsia species have relatively narrow leaves covered by water absorbing trichomes on their surface,T. multiflora in northern Peru andT. tragophoba in northern Chile are tank-forming species where the bases of the leaves form a water-containing reservoir. The occurrence of the latter as a local endemic in hyperarid northern Chile is remarkable since it occurs thousands of kilometers south of its closest potential relatives in the central Andes.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号