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1.
The broadleaved evergreen forests of the East Asian warm temperate zone are characterised by their high biodiversity and endemism, and there is therefore a need to extend our understanding of its genetic diversity and phylogeographic patterns. Castanopsis (Fagaceae) is one of the dominant tree species in the broadleaved evergreen forests of Japan. In this study we investigate the genetic diversity, genetic structure and leaf epidermal morphology of 63 natural populations of C. sieboldii and C. cuspidata, using 32 Expressed Sequence Tag associated microsatellites. The overall genetic differentiation between populations was low (G ST = 0.069 in C. sieboldii and G ST = 0.057 in C. cuspidata). Neighbor-joining tree and Bayesian clustering analyses revealed that the populations of C. sieboldii and C. cuspidata were genetically clearly differentiated, a result which is consistent with the morphology of their epidermal cell layers. This suggests that C. sieboldii and C. cuspidata should be treated as independent species, although intermediate morphologies are often observed, especially at sites where the two species coexist. The higher level of genetic diversity observed in the Kyushu region (for both species) and the Ryukyu Islands (for C. sieboldii) is consistent with the available fossil pollen data for Castanopsis-type broadleaved evergreen trees during the Last Glacial Maximum and suggests the existence of refugia for Castanopsis forests in southern Japan. Within the C. sieboldii populations, Bayesian clustering analyses detected three clusters, in the western and eastern parts of the main islands and in the Ryukyu Islands. The west-east genetic differentiation observed for this species in the main islands, a pattern which is also found in several plant and animal species inhabiting Castanopsis forests in Japan, suggests that they have been isolated from each other in the western and eastern populations for an extended period of time, and may imply the existence of eastern refugia.  相似文献   

2.
To promote programs for the conservation and restoration of the endangered species Primula sieboldii, we examined genetic variation at eight microsatellite loci among and within 32 remnant wild populations throughout Japan. Total allelic diversity within a population was higher in larger populations, but not so after rarefaction adjustment. The positive relationship between population size and the inbreeding coefficient may suggest that more heterozygous genets tend to survive the habitat contraction possibly because of the higher fitness associated with heterozygosity. By principal coordinate analysis and Bayesian analysis, we detected four genetic groups (Hokkaido, northern Honshu, central Honshu, and western Japan), which could be recognized as management units of P. sieboldii. If supplementation with plants from other populations were planned, it should be conducted among populations which belong to the same management unit and which are likely to represent the same adaptive variation.  相似文献   

3.
Viola grayi, a coastal violet, is found on sandy seashores in limited regions in Japan, but not on rocky sea cliffs or in inland areas. This stemmed violet is classified in the subsection Rostratae. Because of recent human activity on sandy seashores, this species is now recorded as endangered. The present status of this species was surveyed and its genetic diversity was analyzed using 17 newly developed simple sequence repeat markers. The results are compared with those for two commonly found inland violet species in the same subsection, V. grypoceras and V. kusanoana. The coastal violet populations showed markedly lower genetic diversity than those of the common species, V. grypoceras, whereas V. kusanoana showed intermediate genetic diversity. About a half of the total genetic variation of V. grayi is found among populations in analysis of molecular variance. In contrast, only less than 25% of the total variation is found among populations for the two common violets. These three species showed a remarkably high inbreeding coefficient, which indicates high inbreeding under natural mating conditions, although these species have both chasmogamous and cleistogamous flowers. In a population-based dendrogram, V. grayi was clustered in a single and concise group, whereas V. grypoceras and V. kusanoana were found in somewhat discrete positions. In the Bayesian analysis of genetic structure of the coastal violet, delta K was the highest at K = 7, and the seven clusters almost correspond to seven populations studied here. Implications of the conservation of this endangered coastal violet are presented.  相似文献   

4.
The aim of this paper is to review the experimental studies performed with two important species (i.e. Vaccinium myrtillus and Vaccinium vitis-idaea) of the shrub layer of boreal forests. The focus is on ecophysiology and stress tolerance under conditions of air pollution and global change. Our objective was to make an overview of studies of abiotic stress related to global change on the above species, and discuss the reported effects of these environmental factors. These issues include nitrogen, heavy metals, radionuclides, salt, ozone, carbon dioxide, warming climate, declining snow cover, periodic droughts, fire and elevated UV radiation. The findings suggest that both species are relatively tolerant to many abiotic environmental stresses: increased nitrogen and metal supply have negligible impacts on these species, as the atmospheric gaseous compounds reported. In some cases the effects are even positive, since extra nitrogen may improve the frost hardiness of V. vitis-idaea, and V. myrtillus may even benefit from elevated CO2. Both species also seem to recover well from fires. However, the reports demonstrated that both have species-specific areas of weakness: (1) V. myrtillus is susceptible to stress caused by warming winter, and (2) frost hardiness of V. vitis-idaea may be reduced under enhanced UV radiation.  相似文献   

5.
Random amplified polymorphic DNA (RAPD) fingerprinting was used to study species boundaries in six closely related NE Turkish Lilium (Liliaceae) taxa of the section Liriotypus. The investigated taxa were L. ciliatum, L. akkusianum, L. ponticum, L. kesselringianum, L. armenum, and L. szovitsianum. Of the 108 primers screened, 11 provided polymorphic and reproducible bands. A total of 93 polymorphic bands were scored for 122 individuals from 18 populations of the six Lilium taxa and principle coordinate analysis and neighbour-joining cluster analysis based on these RAPD profiles were performed. The results demonstrate a clear distinction between the two species L. ciliatum and L. akkusianum, and the other four species. While populations of the two species groups are found to be allopatrically distributed, the two species groups overlap in their geographical ranges. Analysis of molecular variance (AMOVA) indicated that nearly half of the total molecular variance is found within the individual populations and that the molecular variance among species is as high as the variance within the individual species, indicating that genetic differentiation of the species is rather weak.  相似文献   

6.
American cranberry (Vaccinium macrocarpon) is a perennial, woody plant species, native to North American bogs and wetlands. Cranberries represent one of the few agriculturally important native plants in which wild gene pools are still readily available within the undeveloped wetlands of the northern US and Canada. Earlier studies have reported low genetic variation in V. macrocarpon at the species and population level. However, in this study, we characterised 229 individuals of wild V. macrocarpon and V. oxycoccos (small cranberry) from Wisconsin and 22 accessions using microsatellite markers and observed substantial genetic variation and differentiation within and among populations and species. While V. macrocarpon was analysed using 108 alleles from 11 microsatellite loci revealing 42 unique genotypes, V. oxycoccos was analysed using 156 alleles from eight loci revealing 28 unique genotypes. There were a total of 182 alleles found in both species combined with 156 of those alleles present in V. oxycoccos and 84 alleles found in V. macrocarpon. All eight loci possessed species‐specific alleles with V. oxycoccos possessing 98 private alleles versus 26 private alleles found V. macrocarpon, and 58 alleles were found in common between both species. Our data will be valuable not only for future wild cranberry diversity and population genetics research, but for other cranberry breeding and genetics studies.  相似文献   

7.
Mortiño (Vaccinium floribundum Kunth) is a deciduous perennial shrub endemic to the high Andes of South America. Despite a rich ethnobotanic history among indigenous communities, mortiño remains a wild species vulnerable to extinction from the ongoing fragmentation of its natural habitat. This study assessed the degree of genetic diversity and population structure of Ecuadorian V. floribundum as a preliminary step towards the establishment of effective conservation and sustainable-agriculture strategies. Mortiño individuals (126 in total) sampled from 3 regions in the northern highlands of Ecuador were characterized using 11 heterologous SSR markers originally developed for Vaccinium corymbosum. Expected heterozygosity (He = 0.49) revealed a moderate degree of genetic diversity for Ecuadorian mortiño, and pairwise F statistics between sampling regions (0.019≤ Fst ≤0.041) demonstrated low-to-moderate population differentiation. Population structure analysis clustered mortiño germplasm into 3 groups, each representing the 3 distinct regions from where samples were collected. The geographic patterning of genetic diversity for V. floribundum could be explained by an isolation-by-distance model, where physical barriers along the Andean highlands reduce genetic exchange between distanced populations. To confirm the latter, this study should extend to a wider sampling range, covering other regions along the Andean alley where the species is found.  相似文献   

8.
Madagascar has 59 described species of Coffea, of which 42 are listed as critically endangered, endangered, or vulnerable by the criteria of the Red List Category system of the World Conservation Union (IUCN). The littoral forest of Madagascar is a distinctive type of humid evergreen forest restricted to unconsolidated sand located within a few kilometers of the Indian Ocean, now persisting only as small fragments with ca. 10 % of its original range remaining. In an attempt to understand the genetic diversity of Madagascan coffee species, we studied ex situ and in situ populations of Coffea commersoniana, an endemic species of the littoral forests of southeastern Madagascar and soon to be impacted by mining activities in that region. The in situ populations studied showed higher genetic diversity than the ex situ population. The genetic partitioning among the two in situ populations of C. commersoniana was high enough to necessitate keeping the two populations separate for restoration purposes. Based on these findings, recommendations for conservation management (in situ and ex situ) are made.  相似文献   

9.
With increasing temperature and anthropogenic activity, endangered alpine species in the high altitudes of the Qinghai-Tibet Plateau face high risk of extinction; however, they have received little attention in the past. In this study, we used 12 nuclear and nine chloroplast microsatellites (simple sequence repeats, SSR) to assess genetic diversity within and among the only two populations of the highly endangered alpine species Sinadoxa corydalifolia (Adoxaceae). We identified only one individual exhibiting clonal reproduction across all 160 extant plants. The levels of genetic variability were estimated to be very low, with the allele number Na = 3.2 and the expected heterozygosity He = 0.368. The genetic differentiation is extremely high between the two regional populations (FST = 0.214), with a limited rate of gene flow in the recent past. In addition, numerous endemic alleles were found for each subpopulation within each population. Our analyses suggest that it is critical not only to conserve all surviving individuals of the two populations in situ but also to mediate gene flow artificially between subpopulations within each population in this endangered species.  相似文献   

10.
Dense ungulate populations in forest accompanied by high grazing intensities have the potential to affect plant population dynamics, and such herbivory effects on populations are hypothesised to differ along environmental gradients. We investigated red deer grazing and resource interaction effects on the performance and dynamics of the functionally important boreal shrub Vaccinium myrtillus using integral projection models (IPMs). We sampled data from 900 V. myrtillus ramets in 30 plots in two consecutive years across the boreo-nemoral pine forest on the island Svanøy, western Norway. The plots spanned two environmental gradients: a red deer grazing intensity gradient (assessed by Cervus elaphus faecal pellets), and a relative resource gradient (DCA-ordination of species composition). The use of IPMs enabled projections of population growth rate (λ) using continuous plant size instead of forcing stage division upon the demographic data. We used the environmental gradients as continuous variables to explain the dynamics of V. myrtillus populations and found that both increasing grazing intensity and resource levels negatively affected λ of the V. myrtillus populations. Interestingly, these factors interacted: the negative effects of grazing were strongest in the resource-rich vegetation, and higher resource levels reduced λ more strongly than at low resource levels when grazing intensities became higher. Populations with λ > 1 were projected if the grazing intensity was less than or equal to the mean grazing intensity on the island, and indicated that V. myrtillus is relatively tolerant of grazing. Variance decomposing showed that the decrease of λ along the grazing gradient, both at low and high resource levels, was largely caused by reductions in plant growth. The use of IPMs together with important environmental gradients offered novel possibilities to study the synthesised effect of different factors on plant population dynamics. Here, we show that the population response of an abundant boreal shrub to ungulate grazing depends on resource level.  相似文献   

11.
Knowledge of genetic connectivity is useful for understanding of the recovery potential of coral populations after various disturbances, such as coral mass bleaching. Population genetic studies in corals are mostly restricted to Australian and Caribbean species; studies in the northern Pacific are relatively limited. Using microsatellite markers, the population genetics of Acropora sp. 1 was examined between two regions in Japan, the Okinawa-Aka and Bonin Islands, which are separated by approximately 1,500 km of open water in a high-latitude area. Statistically significant but small genetic differentiation in Acropora sp. 1 was detected between and within these regions. Genetic diversity was not obviously reduced in populations of the Bonin Islands, which are relatively isolated. Thus, some level of connectivity appears to be maintained between the two regions, likely because of the high dispersal ability of this broadcast spawner.  相似文献   

12.
For species that are habitat specialists or sedentary, population fragmentation may lead to genetic divergence between populations and reduced genetic diversity within populations, with frequent inbreeding. Hundreds of kilometres separate three geographical regions in which small populations of the endangered Eastern Bristlebird, Dasyornis brachypterus, a small, ground-dwelling passerine that occurs in fire-prone bushland in eastern Australia, are currently found. Here, we use mitochondrial and microsatellite DNA markers to: (i) assess the sub-specific taxonomy designated to northern range-edge, and central and southern range-edge D. brachypterus, respectively, and (ii) assess levels of standing genetic variation and the degree of genetic subdivision of remnant populations. The phylogenetic relationship among mtDNA haplotypes and their spatial distribution did not support the recognised subspecies boundaries. Populations in different regions were highly genetically differentiated, but in addition, the two largest, neighboring populations (located within the central region and separated by ~50 km) were moderately differentiated, and thus are likely closed to migration (microsatellites, F ST = 0.06; mtDNA, F ST = 0.12, ?? ST = 0.08). Birds within these two populations were genotypically diverse and apparently randomly mating. A long-term plan for the conservation of D. brachypterus??s genetic diversity should consider individual populations as separate management units. Moreover, managers should avoid actively mixing birds from different populations or regions, to conserve the genetic integrity of local populations and avoid outbreeding depression, should further translocations be used as a recovery tool for this species.  相似文献   

13.
An understanding of the genetic control of freezing tolerance (FT) in woody perennials is important for the effective selection and development of plants with a broader climatic adaptation. This study was undertaken to examine the inheritance and gene action of FT in segregating populations of a woody perennial blueberry (Vaccinium, section Cyanococcus). Two backcross populations were derived from interspecific hybrids of the diploid species Vaccinium darrowi and Vaccinium caesariense, which are widely divergent in their FT. The bud FTs of uniformly cold acclimated plants of parental, F1, and two backcross populations were evaluated with a laboratory controlled freeze-thaw regime, followed by a visual assessment of injury. FT (LT50) was defined as the temperature causing 50% of the flower buds to be injured. Data indicate that the two parents were homozygous for genes for low or high FT. Freezing-tolerance values of the parental and F1 populations indicate that freeze-sensitivity is a partially dominant trait. Results from reciprocal crosses revealed that there was no significant maternal influence on freezing tolerance. Parental phenotypes were fully recovered in 40–42 plants of each testcross population, suggesting that FT is determined by relatively few genes. The degree of dominance and an analysis of generation means revealed that FT in blueberry is controlled largely by additive gene effects and, to a lesser degree, by dominance gene effects. Testing of various genetic models indicated that FT inheritance can be adequately explained by a simple additive-dominance model; however, two epistatic models involving additive-additive and dominance-dominance interactions also fit the data. Received: 25 May 1999 / Accepted: 16 June 1999  相似文献   

14.
Historical events such as colonisation, spatial distribution across different habitats, and contemporary processes, such as human-mediated habitat fragmentation can leave lasting imprints on the population genetics of a species. Orchids currently comprise 17% of threatened flora species in Australia (Environment Protection and Biodiversity Conservation Act 1999) due to the combination of fragmentation and illegal harvesting (Benwell in Recovery plan, swamp orchids Phaius australis, Phaius tancarvilliae, NSW National Parks and Wildlife Service, Sydney, 1994; Jones in A complete guide to native orchids of Australia including the island territories, 2nd edn, Reed Natural History, Sydney, 2006; DE in Phaius australis in species profile and threats database, Department of the Environment. http://www.environment.gov.au/sprat, 2015). The federally endangered Swamp Orchid Phaius australis has a disjunct distribution across an almost 2000 km latitudinal range along Australia’s east coast but it was estimated that 95% of the populations have been lost since European settlement (Benwell 1994). Phaius australis is endangered due to illegal collection and habitat loss that has resulted in limited connectivity between populations, in ecosystems that are vulnerable to climate change. Thus the genetic impacts of its history combined with more recent fragmentation may have impacts on its future viability especially in light of changing environmental conditions. Thirty-four populations were sampled from tropical north Queensland to the southern edge of the subtropics in New South Wales. Population genetics analysis was conducted using 13 polymorphic microsatellite markers developed for the species using NextGen sequencing. Spatial genetic patterns indicate post-colonisation divergence from the tropics southwards to its current climate niche limits. Genetic diversity is low across all populations (A?=?1.5, H e  = 0.171), and there is little evidence of genetic differentiation between regions. Consistent with population genetic theory, the historic loss of populations has resulted in significantly lower genetic diversity in small populations compared to large (P, A, He; p?<?0.05). The viability and persistence of P. australis populations now and in a changing climate are discussed in the context of conservation priorities.  相似文献   

15.
Litsea szemaois (Lauraceae) is an endemic and endangered species from the tropical rain forests of Xishuangbanna, southern Yunnan, SW China, but habitat fragmentation, especially exacerbated by rubber planting, has caused a decline in population size of the species. AFLP and ISSR were used to investigate the genetic diversity and population structure of eight populations from across its known distribution. Three AFLP and ten ISSR primer combinations produced a total of 203 and 77 unambiguous and repeatable bands respectively, of which 164 (80.8%) and 67 (87.0%) were polymorphic for the two markers. These two markers showed that Litsea szemaois exhibits comparatively high genetic diversity at species level (heterozygosity (hs) = 0.2109) relative to some other Lauraceae. Most of the genetic variation was partitioned within populations, but genetic differentiation between populations was significant and relatively high (Φ st = 0.2420, θ= 0.1986) compared with other tropical plants. The genetic characteristics of L. szemaois may be related to its outbreeding system, insect pollination and fragmented distribution. Because L. szemaois is dioecious and slow to mature, ex situ conservation across its genetic diversity is unlikely to succeed, although seedlings grow well under cultivation. Thus, in situ conservation is very important for this endangered species, especially as only 133 adult individuals are known in the wild. In particular, the Nabanhe and Mandian populations should be given a high conservation priority due to their higher genetic diversity, larger population size and better field condition, but wider sampling is required across all populations to determine additional areas with significant genetic conservation value.  相似文献   

16.
17.
During recent decades, over 40% of Japanese estuarine tidal flats have been lost due to coastal developments. Local populations of the saltmarsh sesarmid crab Clistocoeloma sinense, designated as an endangered species due to the limited suitable saltmarsh habitat available, have decreased accordingly, being now represented as small remnant populations. Several such populations in Tokyo Bay, have been recognised as representing distributional limits of the species. To clarify the genetic diversity and connectivity among local coastal populations of Japanese Clistocoeloma sinense, including those in Tokyo Bay, mitochondrial DNA analyses were conducted in the hope of providing fundamental information for future conservation studies and an understanding of metapopulation dynamics through larval dispersal among local populations. All of the populations sampled indicated low levels of genetic diversity, which may have resulted from recent population bottlenecks or founder events. However, the results also revealed clear genetic differentiation between two enclosed-water populations in Tokyo Bay and Ise-Mikawa Bay, suggesting the existence of a barrier to larval transport between these two water bodies. Since the maintenance of genetic connectivity is a requirement of local population stability, the preservation of extant habitats and restoration of saltmarshes along the coast of Japan may be the most effective measures for conservation of this endangered species.  相似文献   

18.
Background and AimsUnderstanding how plant allometry, plant architecture and phenology contribute to fruit production can identify those plant traits that maximize fruit yield. In this study, we compared these variables and fruit yield for two shrub species, Vaccinium angustifolium and Vaccinium myrtilloides, to test the hypothesis that phenology is linked to the plants’ allometric traits, which are predictors of fruit production.MethodsWe measured leaf and flower phenology and the above-ground biomass of both Vaccinium species in a commercial wild lowbush blueberry field (Quebec, Canada) over a 2-year crop cycle; 1 year of pruning followed by 1 year of harvest. Leaf and flower phenology were measured, and the allometric traits of shoots and buds were monitored over the crop cycle. We hand-collected the fruits of each plant to determine fruit attributes and biomass.Key ResultsDuring the harvesting year, the leafing and flowering of V. angustifolium occurred earlier than that of V. myrtilloides. This difference was related to the allometric characteristics of the buds due to differences in carbon partitioning by the plants during the pruning year. Through structural equation modelling, we identified that the earlier leafing in V. angustifolium was related to a lower leaf bud number, while earlier flowering was linked to a lower number of flowers per bud. Despite differences in reproductive allometric traits, vegetative biomass still determined reproductive biomass in a log–log scale model.ConclusionsGrowing buds are competing sinks for non-structural carbohydrates. Their differences in both number and characteristics (e.g. number of flowers per bud) influence levels of fruit production and explain some of the phenological differences observed between the two Vaccinium species. For similar above-ground biomass, both Vaccinium species had similar reproductive outputs in terms of fruit biomass, despite differences in reproductive traits such as fruit size and number.  相似文献   

19.
Vaccinium myrtillus and Vaccinium vitis‐idaea are two dwarf shrubs widespread in the European Alps. We studied the hydraulics of these species hypothesizing that (1) the hydraulic architecture of dwarf shrubs differs from trees, (2) hydraulic properties reflect the species' ecological amplitude and (3) hydraulic properties vary spatially and seasonally. Key hydraulic parameters (osmotic potential, turgor loss point, xylem hydraulic conductivity, vulnerability to drought‐induced embolism, stomata closure, drought‐induced cell damage and embolism repair) and related wood anatomical traits (conduit diameter and conduit wall reinforcement) were analyzed at four sites in Tyrol, Austria. Both species exhibited low hydraulic safety as well as low hydraulic efficiency. Fifty percentage embolism accumulated at ?2.08 (V. myrtillus) and ?1.97 MPa (V. vitis‐idaea), 88% stomata closure was at ?2.19 and ?2.35 MPa, respectively. After drought, both species showed embolism repair on re‐watering. Site‐specific variation within species was low, while seasonal changes in embolism resistance and turgor loss point were observed. Results indicate that studied Vaccinium species have a high risk for embolism formation. This is balanced by refilling capacities, which are probably based on the small growth height of dwarf shrubs. V. vitis‐idaea, which occurs on drier sites, showed more efficient repair and a lower turgor loss point than V. myrtillus.  相似文献   

20.
In this study, we assessed geographic patterns of genetic variations in nuclear and chloroplast genomes of two related native oaks in Japan, Quercus aliena and Q. serrata, in order to facilitate development of genetic guidelines for transfer of planting stocks for each species. A total of 12 populations of Q. aliena and 44 populations of Q. serrata were analyzed in this study. Genotyping of nuclear microsatellites in Q. aliena was done with only nine populations (n = 212) due to limited numbers of individuals in two populations, while all 12 populations (n = 89) were used in sequencing chloroplast DNA (cpDNA). In Q. serrata, 43 populations (n = 1032) were genotyped by nuclear microsatellite markers, while cpDNA of 44 populations (n = 350) was sequenced. As anticipated, geographic patterns detected in the variations of Q. aliena’s nuclear genome and its chloroplast haplotype distribution clearly distinguished northern and southern groups of populations. However, those of Q. serrata were inconsistent. The geographic distribution of its chloroplast haplotypes tends to show the predicted differentiation between northern and southern lineages, but geographic signals in the genetic structure of its nuclear microsatellites are weak. Therefore, treating northern and southern regions of Japan as genetically distinct transferrable zones for planting stocks is highly warranted for Q. aliena. For Q. serrata, the strong NE-SW geographic structure of cpDNA should be considered.  相似文献   

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