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1.
Replicate harvest simulations were conducted in a large natural population of Panax quinquefolius L.␣(Araliaceae) to determine the selective effects of harvest. We investigated how minimum size requirements and the influence
of size on apparency to human harvesters could result in preferential removal of large plants. To determine which plants were
encountered in the large population, harvesters were tracked using GPS as they searched for every legally harvestable, adult
plant they could find. Plants were assigned stage-specific fitness measures based on their contributions to population growth
rate (λ) under three demographically based harvest regimes: no harvest, harvest and harvest removing seeds. Plant size was
codified into a size-index equal to the product of total leaf area and stem height. Heterogeneity of slopes was tested to
determine if the selection gradients (β) describing the relationship between fitness and size varied among the three harvest
regimes. Harvest differentially reduced the fitness of larger plants in one of four individual harvest simulations. The combined
harvest simulation significantly altered the selection regime for size in the population of juvenile and adult (harvestable)
plants. Seed removal by harvesters intensified fitness declines for larger plants. Because larger plants contribute most to
population growth, the selective effects of harvest could result in a shift in the evolutionary dynamics of this species with
significant conservation implications. 相似文献
2.
Cypripedium macranthos var. rebunense is an endangered plant endemic to Rebun Island, Japan. A proper understanding of genetic diversity is needed when conducting
conservation programs for rare and endangered species. We therefore examined the genetic diversity of C. macranthos var. rebunense using allozyme markers with a view to future conservation. Our study revealed that C. macranthos var. rebunense has relatively high genetic diversity (P was 0.62, n
a and n
e were 1.85 and 1.28 respectively, and H
o and H
e were 0.163 and 0.187, respectively) when compared with other plant taxa. The natural habitats of C. macranthos var. rebunense are geographically separated into northern and the southern populations. Disappearance of alleles and increase in homozygosity
expected as a result of the bottleneck effect were observed, particularly in the southern populations composed of a small
number of plants. As additional negative effects (inbreeding depression and further genetic drift) due to fragmentation are
predicted in these populations, the southern populations may show deterioration of genetic diversity in the near future. 相似文献
3.
Vesna Milankov Gunilla Ståhls Jelena Stamenković Ante Vujić 《Conservation Genetics》2008,9(5):1125-1137
The genetic structure of 10 populations of the Merodon aureus group from the Balkan Peninsula was examined through allozyme electrophoresis and mitochondrial DNA sequencing of the cytochrome
c oxidase subunit I (COI). Six diagnosable cryptic taxa were identified within the morphologically defined species M. aureus Fabricius, 1805 and M. cinereus (Fabricius, 1794), with clear separation of the populations (((M. aureus A + M. aureus B) + cinereus complex) + M. aureus C). The parsimony analysis of COI sequence data of the aureus–cinereus complex using Merodon avidus A species as an outgroup resulted in two main clades, (M. aureus A + M. aureus B) and ((M. aureus C + M. cinereus B + M. cinereus C) + M. cinereus A), which differed on average by 5.7%. The observed spatial distribution of the taxonomic diversity of the group suggested
that these taxa originated from a common ancestral population in the Mediterranean. Identification of genetic uniqueness and
genetic endemism emphasizes the importance of molecular markers and estimation of genetic diversity in recognition of conservation
units. The primary goals of the conservation measures that we propose are the protection of phylogenetic lineages within the
highly diverse M. aureus group taxa and conservation of the genetic variation through management of important areas. 相似文献
4.
Genetiana crassicaulis is one of famous Chinese medicinal plant. The over-collection for its root has caused its dramatic reduction. In order to
devise adequate conservation and management strategies for this species, it is important to characterize its genetic diversity
and understand its population structure. Here, 10 polymorphic microsatellite markers have been developed. AC/TG microsatellite
was enriched by combining biotin capture method. Polymorphism of each locus was assessed in 30 individuals from six populations.
The number of alleles ranged from 2 to 9 and the expected heterozygosity ranged from 0.32 to 0.78. 相似文献
5.
Esther E. Uchendu Gopinadhan Paliyath Dan C. W. Brown Praveen K. Saxena 《In vitro cellular & developmental biology. Plant》2011,47(6):710-718
North American ginseng (NAG) (Panax quinquefolius L.) is a medicinally important plant with multiple uses in the natural health product industry. As seed propagation is time-consuming
because of the slow growth cycle of the plant, in vitro propagation using a bioreactor system was evaluated as an effective approach to accelerate plant production. An efficient
method was developed to multiply nodal explants of NAG using liquid-culture medium and a simple temporary immersion culture
vessel. The effects of plant growth regulators, phenolics, and chemical additives (activated charcoal, melatonin, polyvinylpolypyrrolidone,
and ascorbic acid) were evaluated on in vitro-grown NAG plants. The highest number (12) of shoots per single node was induced in half-strength Schenk and Hildebrandt basal
medium containing 2.5 mg/l kinetin, in which 81% of the cultured nodes responded. In a culture medium with 0.5 mg/l α-naphthalene
acetic acid (NAA), roots were induced in 78% of the explants compared to 50% with a medium containing indole-3-acetic acid.
All of the resulting plants appeared phenotypically normal, and 93% of the rooted plants were established in the greenhouse.
Phenolic production increased significantly (P < 0.05) over a 4-wk culture period with a negative impact on growth and proliferation. Activated charcoal (AC; 50 mg/l) significantly
reduced total phenolic content and was the most effective treatment for increasing shoot proliferation. Shoot production increased
as the phenolic content of the cultures decreased. The most effective treatment for NAG development from cultured nodal explants
in the bioreactor was 2.5 mg/l kinetin, 0.5 mg/l NAA, and 50 mg/l AC in liquid culture medium. This protocol may be useful
in providing NAG tissues or plants for a range of ginseng-based natural health products. 相似文献
6.
Biological invasions offer excellent systems to study the evolutionary processes involved in introductions of species to new
ranges. Molecular markers can reveal invasion histories and the effects of introductions on amounts and structuring of genetic
variation. We used five polymorphic microsatellite loci to elucidate genetic diversity and population structure between native
range and introduced range populations of a prominent North American rangeland weed, Centaurea diffusa (Asteraceae). We found that the total number of alleles and the number of private alleles was slightly higher in the native
Eurasian range, and that allelic richness did not differ between the ranges, indicating overall levels of diversity were similar
in Eurasia and North America. It therefore seems unlikely that this invasion has been affected by genetic bottlenecks or founder
effects. Indeed, results of assignment tests suggest that multiple introductions have contributed to North America’s C. diffusa invasion. Additionally, assignment tests show that both Eurasian and North American sites had a strong pattern of mixed genetic
ancestry. This mixed assignment corresponded to a lack of geographic population structure among Eurasian samples. The lack
of population structure in the native range conflicts with general expectations and findings to date for invasion genetics,
and cautions that even species’ native ranges may show signs of recent ecological upheaval. Despite the mixed assignments,
North American samples showed strong population structure, suggesting that the invasion has been characterized by long-range
dispersal of genetically distinct propagules across the introduced range. 相似文献
7.
Kyung-Ho Ma Anupam Dixit Young-Chang Kim Dong-Yun Lee Tae-San Kim Eun-Gi Cho Yong-Jin Park 《Conservation Genetics》2007,8(6):1507-1509
Panax ginseng C.A. Meyer, commonly known as Korean or Asian ginseng, is a perennial herb native to Korea and China. Its roots are highly
prized for several medicinal properties. The present study describes development and characterization of twenty-two polymorphic
microsatellite markers for this species. A total of 99 alleles were detected with an average of 4.5 alleles per locus across
20 accessions. Values for observed (H
O
) and expected (H
E
) heterozygosities ranged from 0.05 to 1.00 and from 0.18 to 0.73, respectively. Eleven loci deviated from Hardy–Weinberg
equilibrium (P < 0.001). Significant (P < 0.05) heterozygote deficiency was observed at 13 loci. Exact test for linkage disequilibrium showed significant values
(P < 0.05) between 12 pairs of loci. These microsatellite markers provide powerful tools for understanding population and conservation
genetics of this species and also for genetic differentiation and authentication of different Panax species being used in commercial ginseng products. 相似文献
8.
Michal Moyal Ben Zvi Amir Zuker Marianna Ovadis Elena Shklarman Hagit Ben-Meir Shamir Zenvirt Alexander Vainstein 《Molecular breeding : new strategies in plant improvement》2008,22(4):543-553
As a major contributor to the flower market, Gypsophila paniculata is an important target for the breeding of new varieties. However, gypsophila breeding is strongly hampered by the sterility
of this species’ genotypes and the lack of a genetic-transformation procedure for this genus. Here we describe the establishment
of a transformation procedure for gypsophila (Gypsophila paniculata L.) based on Agrobacterium inoculation of highly regenerative stem segments. The transformation procedure employs stem explants derived from GA3-pretreated mother plants and a two-step selection scheme. The GA3 treatment was crucial for obtaining high gene-transfer frequencies (75–90% GUS-expressing explants out of total inoculated
explants), as shown using three different gypsophila varieties. An overall transformation efficiency of five GUS-expressing
shoots per 100 stem explants was demonstrated for cv. Arbel. The applicability of the transformation system to gypsophila
was further reinforced by the generation of transgenic plants expressing Agrobacterium rhizogenes
rolC driven by a CaMV 35S promoter. Transgenic gypsophila plantlets exhibited extensive rooting and branching, traits that could
be beneficial to the ornamental industry. 相似文献
9.
Tribulus terrestris is well known for its medicinal importance in curing urino-genital disorders. Amplified fragment length polymorphism (AFLP),
selective amplification of microsatellite polymorphic loci (SAMPL), inter-simple sequence repeat (ISSR) and randomly amplified
polymorphic DNA (RAPD) markers were used for the first time for the detection of genetic polymorphism in this medicinal herb
from samples collected from various geographical regions of India. Six assays each of AFLP and SAMPL markers and 21 each of
ISSR and RAPD markers were utilized. AFLP yielded 500 scorable amplified products, of which 82.9% were polymorphic. SAMPL
primers amplified 488 bands, 462 being polymorphic (94.7%). The range of amplified bands was 66 [(TC)8G + M-CAG] to 98 [(CA)6AG + M-CAC] and the percentage polymorphism, 89.9 [from (CT)4C (AC)4A + M-CTG] to 100 [from (GACA)4 + M-CTA]. The ISSR primers amplified 239 bands of 0.4–2.5 kb, 73.6% showed polymorphism. The amplified products ranged from
5 to 16 and the percentage polymorphism 40–100. RAPD assays produced 276 bands, of which 163 were polymorphic (59%). Mantel
test employed for detection of goodness of fit established cophenetic correlation values above 0.9 for all the four marker
systems. The dendrograms and PCA plots derived from the binary data matrices of the four marker systems are highly concordant.
High bootstrap values were obtained at major nodes of phenograms through WINBOOT software. The relative efficiency of the
four molecular marker systems calculated on the basis of multiplex ratio, marker index and average heterozygosity revealed
SAMPL to be the best. Distinct DNA fingerprinting profile, unique to every geographical region could be obtained with all
the four molecular marker systems. Clustering can be a good indicator for clear separation of genotypes from different regions
in well-defined groups that are supported by high bootstrap values. 相似文献
10.
Ranunculus nipponicus (Makino) Nakai is a vulnerable aquatic macrophyte in the Kinki district, which is the southernmost distribution of this species
in Japan. The genetic diversity and structure within and among eleven extant populations were assessed using the inter-simple
sequence repeats (ISSR) polymerase chain reaction in association with combinations of propagation pattern (clonal and/or seeds)
and genotypic geographical structure. In total, 53 bands were amplified, of which 18 (34%) were polymorphic. Analysis of the
ISSR bands identified 46 genotypes among 81 individuals from one stream population and 72 distinct genotypes among 147 individuals
in the Kinki district. An unweighted pair group method with arithmetic mean (UPGMA) dendrogram showed some unity among upstream
and downstream subpopulations within one stream and eleven populations. The Shannon index of genetic diversity was 0.109 for
one stream population and 0.313 for total genetic diversity, suggesting relatively high genetic diversity. Analysis of molecular
variance (AMOVA) revealed that 84.1% of the total genetic diversity occurred among populations and the remaining diversity
(15.9%) occurred within populations. Significant genetic differentiation occurred among populations in the Kinki district.
These results suggest that conservation of each population is important for maintaining genetic diversity of R. nipponicus in this district.
An erratum to this article can be found at 相似文献
11.
Huang Heping Gao Shanlin Chen Lanlan Jiao Xiaoke 《In vitro cellular & developmental biology. Plant》2008,44(5):448-455
Dioscorea zingiberensis is an important medicinal plant and a source of diosgenin in China. We report research on the induction, characteristics,
and chemical assays of polyploid plants of D. zingiberensis. Immersing calli in 0.3% colchicine solution for 16 h prior to culture induced a high number of autotetraploid plants. The
induction rate reached as high as 36.7% of treated calli. More than 50 lines of autotetraploid plants were obtained. All tetraploid
plants showed typical polyploidy characteristics. Twenty selected tetraploid lines were transferred to the field for determination
of morphological characteristics and for chemical assays. Six elite lines have been selected for further selection and breeding
into new varieties for commercial production. 相似文献
12.
A high-frequency and simple procedure for Agrobacterium tumefaciens-mediated genetic transformation of the medicinal plant Salvia miltiorrhiza was developed. Leaf discs were pre-cultured on MS medium supplemented with 6.6 μmol l−1 BAP and 0.5 μmol l−1 NAA for one day, then co-cultured with A. tumefaciens strain EHA105 harboring the plasmid pCAMBIA 2301 for three days on the same medium. Regenerated buds were obtained on selection
medium (co-culture medium supplemented with 60 mg l−1 kanamycin and 200 mg l−1 cefotaxime) after two cycles’ culture of 10 days each and then transferred to fresh MS medium with 60 mg l−1 kanamycin for rooting. Fifteen days later, the rooted plantlets were obtained and then successfully transplanted to soil.
The transgenic nature of the regenerated plants was confirmed by PCR, Southern hybridization analysis and GUS histochemical
assay. Averagely, 1.1 independent verified transgenics per explant plated were obtained through this protocol. Adopting this
procedure, positive transformed plants could be obtained within 2–3 months from mature seeds germination to transplant to
soil, and more than 1,000 transgenic plants with several engineered constructs encoding different genes of interest were produced
in our lab in the past two years. 相似文献
13.
The microtubule-binding protein tau has been investigated for its contribution to various neurodegenerative disorders. However,
the findings from transgenic studies, using the same tau transgene, vary widely among different laboratories. Here, we have investigated the potential mechanisms underlying tauopathies
by comparing Drosophila (d-tau) and human (h-tau) tau in a Drosophila model. Overexpression of a single copy of either tau isoform in the retina results in a similar rough eye phenotype. However, co-expression of Par-1 with d-tau leads to lethality, whereas co-expression of Par-1 with h-tau has little effect on the rough eye phenotype. We have found analogous results by comparing larval proteomes. Through genetic
screening and proteomic analysis, we have identified some important potential modifiers and tau-associated proteins. These
results suggest that the two tau genes differ significantly. This comparison between species-specific isoforms may help to clarify whether the homologous
tau genes are conserved.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
This study was supported by the National Science Foundation of China (30270341; 30630028), the Multidisciplinary Program (Brain
and Mind) of the Chinese Academy of Sciences, the Major State Basic Research Program (“973 program”; G2000077800; G2006CB806600;
2006CB911003), the Precedent Project of Important Intersectional Disciplines in the Knowledge Innovation Engineering of the
Chinese Academy of Sciences (KJCX1-09-03). 相似文献
14.
Yessica Rico Consuelo Lorenzo Francisco X. González-Cózatl Eduardo Espinoza 《Conservation Genetics》2008,9(6):1467-1477
The Tehuantepec jackrabbit (Lepus flavigularis) is an endangered species restricted to a small area in the Isthmus of Tehuantepec, Oaxaca, Mexico. To evaluate its phylogeographic
structure, population genetics, and demographic history we sequenced the mitochondrial Control Region hypervariable domain
(CR-1) for 42 individuals representing the entire species range. Phylogenetic patterns indicated that this species is subdivided
into two highly divergent clades, with an average nucleotide genetic distance of 3.7% (TrN) between them. Clades A and B are
geographically distributed in non-overlapping areas to the west and to the east of the Isthmus of Tehuantepec, respectively.
Genetic diversity indices showed reduced genetic variability in L. flavigularis when compared to other species of Lepus within main clades and within populations. This low genetic diversity coupled with the restricted distribution to very small
areas of occurrence and limited gene flow suggest that genetic drift has played an important role in the evolution of this
species. Historical demographic analysis also pointed out that these two clades underwent a recent population expansion that
started about 9,000 years ago for clade A and 3,200 years ago for clade B during the Holocene. Consequently, from the conservation
perspective our results suggest that populations included in clades A and B should be regarded as distinct evolutionary lineages. 相似文献
15.
Range wide versus local patterns of genetic diversity in hornbeam (<Emphasis Type="Italic">Carpinus betulus</Emphasis> L.) 总被引:1,自引:0,他引:1
A study based on AFLP markers was conducted to characterise the present population genetic structure of Carpinus betulus in Europe and to formulate guidelines for the use of this species in plantations on a local scale in Flanders. High within-population diversity and little (but significant) genetic differentiation were detected at both Flemish and European scales. However, there was a pattern of isolation by distance only at the European scale. Within-population gene diversity, a new rarefaction-based measure of number of genotypes (band richness) and percentage of polymorphic loci are lower north of major mountain chains, suggesting that the mountain ranges formed a second bottleneck for the hornbeam during postglacial recolonisation. In Flanders, despite lower gene diversity, there were more polymorphic loci than in other European populations, a pattern that might have been caused by the mixing of material through planting, e.g. in hedges. In view of these findings, it is advised to create a single Flemish seed zone and to use preferentially reproductive material from this seed zone for new plantations in Flanders. 相似文献
16.
Conserving endangered wild rice species requires a thorough understanding of their population genetic structure and appropriate approaches. We applied six and seven microsatellite loci to study the genetic structure of six populations throughout the range of Chinese Oryza rufipogon and Oryza officinalis, respectively. The results showed that O. rufipogon possesses higher levels of genetic diversity but lower differentiation (RS = 3.2713, P = 100.0%, HO = 0.1401, HS = 0.5800, FST = 0.271) than O. officinalis (RS = 2.0545, P = 57.14%, HO = 0.0470, HS = 0.2830, FST = 0.554). Mean population FIS was slightly larger for O. officinalis (FIS = 0.844) than that for O. rufipogon (FIS = 0.755), indicating that O. officinalis has slightly higher departures from Hardy–Weinberg expectations and heterozygosity deficits than O. rufipogon. In addition to different origins and evolutionary histories, O. officinalis has restricted gene flow, high inbreeding, isolated small populations and fewer opportunities of hybridization with other taxa, which may determine major differences in population genetic structure from O. rufipogon. Our results suggest the adoption of a plan of involving fewer populations but more individuals within populations for O. rufipogon, while both the number of populations and the individuals for a sampled population should be almost equally considered for O. officinalis. The known high degree of inbreeding in the populations of both species implies that conservation and restoration genetics should particularly focus on the maintenance of historically significant processes such as high levels of outbreeding, gene flow and large effective population sizes. We finally proposed to further estimate the role of rice gene flow in the conservation of O. rufipogon, and to perform detailed analysis of mating systems in both species for better conservation perspectives of their ecological and evolutionary processes. 相似文献
17.
18.
An efficient procedure for direct organogenesis and regeneration of hop (Humulus lupulus L.) was established. For the first time Agrobacterium-mediated genetic transformation of hop (cv. "Tettnanger") was achieved. Shoot internodes from in vitro cultures were identified as the most suitable type of explant for regeneration. Using this type of explant, a shoot-inducing medium was developed that supported direct organogenesis of approximately 50% of the explants. Plantlets were successfully rooted and transferred to the greenhouse. Overall, in less than 6 months hop cultures propagated in vitro were regenerated to plants in the greenhouse. Agrobacterium-mediated genetic transformation was performed with the reporter gene GUS (-glucuronidase). The presence and function of transgenes in plants growing in the greenhouse was verified by PCR (polymerase chain reaction) and enzyme assay for GUS activity, respectively. We have obtained 21 transgenic plants from 1,440 explants initially transformed, yielding an overall transformation efficiency of 1.5%.Abbreviations BAP 6-Benzylaminopurine - GA3 Gibberellic acid - GUS -Glucuronidase - IAA Indole-3-acetic acid - IBA Indole-3-butyric acid - NAA -Naphthaleneacetic acid - nptII Neomycin phosphotransferase II - PCR Polymerase chain reaction - TDZ 1-Phenyl-3-(1,2,3-thiadiazol-5-yl) urea (thidiazuron)Communicated by H. Lörz 相似文献
19.
20.
Na Chen Yan-Zhuo Yang Xiao-li Yang Xing-xu Zhang Chun-jie Li 《Conservation Genetics》2008,9(4):961-963
Microsatellites are often highly variable and abundant in most complex genomes, therefore are widely used in population genetic
studies. In this study, twelve polymorphic microsatellite loci were isolated and characterized for the Achnatherum inebrians, a plant abundant in grasslands of Northwest China. Characterization of 24 A. inebrians individuals form four geographically distant populations (Gansu, Qinghai, Xinjiang and Inner Mongolia provinces) showed moderate
to high allelic diversity ranging from 3 to 13 alleles per locus, and the expected heterozygosity ranging from 0.41 to 0.67.
No evidence of linkage disequilibrium was found for any locus pairwise comparisons. The markers described here will be useful
for investigating the genetic diversity, genetic structure and gene flow of this species.
Na Chen and Yan-Zhuo Yang contributed equally to this work. 相似文献