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1.
Understanding the patterns of contemporary, pollen-mediated gene flow is of great importance for designing appropriate conservation
strategies. In this study, ten novel polymorphic microsatellite loci were isolated for the rare dioecious tree, Eurycorymbus cavaleriei, and the patterns of pollen dispersal were investigated in an ex situ conserved population. A combination of microsatellite
markers with high-collective exclusion power (0.932) was used to assign paternity to 240 seeds collected from eight maternal
trees. The average effective pollen dispersal distance (δ) was 292.6 m and the frequency distribution of pollen movement suggested extensive pollen movement in the population. The
effective pollen donors per maternal tree (N
ep) ranged from 5 to 10, and the most isolated maternal trees were observed with the largest number of N
ep = 10. Although a trend of near-neighbor mating was found in seven of eight maternal trees, no significant correlations were
detected between the average effective pollen dispersal distance (δ) and the geographic distances (d1 and d2) between maternal and male trees. The increased average effective distance of pollen
dispersal and number of N
ep for isolated maternal trees might be a compound consequence of low density and long-distance flight of pollinators of this
species. The conservation implications of these results are discussed. 相似文献
2.
Abhishek Tripathi Neeta Sharma Vinay Sharma 《World journal of microbiology & biotechnology》2009,25(3):503-512
Hyptis
suaveolens L. (Poit.) essential oil was tested in vitro on the growth and morphogenesis of Fusarium oxysporum f.sp. gladioli (Massey) Snyder & Hansen, which causes Fusarium corm rot and yellows in various susceptible cultivars of gladiolus. The fungitoxicity of the oil was measured by percentage radial growth inhibition using the poisoned food technique (PF)
and volatile activity assay (VA). The mycelial growth of the test fungus was completely inhibited at 0.998 and 0.748 μg ml−1 concentration of oil in PF and VA, respectively. Essential oil was found to be fungicidal in nature at 1.247 and 0.998 μg ml−1 concentration of oil in PF and VA, respectively. Determination of conidial germination in the presence of oil was also carried
out and it was found that the oil exhibited 100% inhibition of conidial germination at 0.450 μg ml−1 concentration. The effect of essential oil on the yield of mycelial weight was observed and it was found that at 0.873 μg ml−1 concentration no mycelium was recorded and 100% inhibition was observed. The fungitoxicity of oil did not change even on
exposure to 100°C temperature or to autoclaving, and the oil also retained its fungicidal nature even after storage of 24 months.
The main changes observed under light microscopy after oil treatment were a decrease and loss of conidiation and anomalies
in the hyphae such as a decrease in the diameter of hyphae and granulation of cytoplasm. The treatment of the oil also showed
highly reduced cytoplasm in the hyphae, showing clear retraction of the cytoplasm from the hyphae and ultimately in some areas
hyphae without cytoplasm were also found. GC-MS studies of the essential oil revealed that the oil consisted of 24 compounds
with 1,8-cineole as major component accounting for 44.4% of the total constituents. 相似文献
3.
Micropropagation of mature wych elm (<Emphasis Type="Italic">Ulmus glabra</Emphasis> Huds.) 总被引:2,自引:0,他引:2
Explants of mature vigorous donor trees of wych elm (Ulmus glabra Huds.) that had not been previously exposed to Dutch elm disease were investigated for the influence of phytohormones and media on shoot multiplication rates and organogenic capacity. The regenerates were micropropagated from cultures that originated from 15-year-old progeny of plus trees. Two plus trees aged over 70 years showed recalcitrant responses. Thidiazuron in combination with 6-benzylaminopurine (BAP) induced a significantly higher number of shoots per explant than the most optimal BAP treatment (5.88 vs. 3.05 shoots). Woody plant medium and Dubovský minimal medium had no significant effects on shoot formation and multiplication rates. All plantlets raised in vitro were phenotypically normal and successfully hardened to ex vitro conditions. Two experimental field plots with 3-year-old in vitro-propagated trees were established.Abbreviations DED: Dutch elm disease - BAP: 6-Benzylaminopurine - IBA: Indole-3-butyric acid - TDZ: Thidiazuron - WPM: Woody Plant Medium - DM: Dubovský Minimal Medium Communicated by D. Bartels 相似文献
4.
Kiyomi Tsutsui Atsushi Suwa Kei’ichi Sawada Toshihide Kato Takeshi A. Ohsawa Yasuyuki Watano 《Journal of plant research》2009,122(5):509-521
Introgression has been considered to be one of main factors leading to phylogenetic incongruence among different datasets
at lower taxonomic levels. In the plants of Pinaceae, the mtDNA, cpDNA, and nuclear DNA (nrDNA) may have different evolutionary
histories through introgression because they are inherited maternally, paternally and biparentally, respectively. We compared
mtDNA, cpDNA, and two low-copy nrDNA phylogenetic trees in the genus Pinus subgenus Strobus, in order to detect unknown past introgression events in this group. nrDNA trees were mostly congruent with the cpDNA tree,
and supported the recent sectional and subsectional classification system. In contrast, mtDNA trees split the members of sect.
Quinquefoliae into two groups that were not observed in the other gene trees. The factors constituting incongruence may be divided into
the following two categories: the different splits within subsect. Strobus, and the non-monophyly of subsect. Gerardianae. The former was hypothesized to have been caused by the past introgression of cpDNA, mtDNA or both between Eurasian and North
American species through Beringia. The latter was likely caused by the chimeric structure of the mtDNA sequence of P. bungeana, which might have originated through past hybridization, or through a horizontal transfer event and subsequent recombination.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
5.
The research on incidence of mistletoe (Viscum album ssp. abietis) on silver fir (Abies alba) was carried out in natural fir stands in Croatia. In the area of Gorski Kotar 32.8 % of the examined dominant fir trees
were infected with mistletoe. The mistletoe incidence was presented according to the damage degrees of silver fir from 0 (healthy
trees) to 4 (dead trees), rated by the crown defoliation and needle discoloration. With the increase of incidence, mistletoe
spreads more onto more vital, i.e. less damaged trees. In the Dinaric Alps 28.6% of the examined fir trees were infected,
this percentage amounting to 27.1% for the mountainous regions between the Sava and Drava rivers.
The site and stand parameters (exposure, elevation, site quality, forest community and crown closure) were analysed in order
to establish whether there was a correlation between these parameters and mistletoe incidence. There was a negative correlation
between the elevation and mistletoe incidence. Among the compartments with a closed stands there were considerably less compartments
with higher mistletoe incidence than among compartments with a sparsely closed and understocked stands. The other analysed
site and stand parameters individually had no significant influence on mistletoe incidence.
The correlation of silver fir mortality in 2004 and mistletoe incidence in 2002/03 was analysed, and their strong correlation
was established. Mistletoe could be considered as a bioindicator of silver fir decline, and probably a significant contributor
to that decline. In the areas where mistletoe incidence is great it can be presumed that silver fir is significantly damaged. 相似文献
6.
Xander M. van der Burgt 《Kew Bulletin》2009,64(2):313-317
Summary
Lecomtedoxa plumosa Burgt (Sapotaceae), a new tree species from the southern part of Korup National Park in Cameroon, is described and illustrated.
The flowers show the characteristics of the genus Lecomtedoxa: for example the staminodes are free and placed alternately to the stamens and corolla lobes. The leaves of the new species
are clearly different from other Lecomtedoxa spp., but they look similar to the leaves of Gluema ivorensis, especially to those of the collections from Cameroon. In total 26 trees ≥ 10 cm dbh were found. The largest trees found
were 36 m high and 74 cm dbh. The trees grow in primary rain forest, in clusters of up to 10 trees on 2 ha, mixed with many
other tree species. The seed dispersal is ballistic. The conservation status of the species is assessed as Endangered, EN
D. 相似文献
7.
Many outstanding questions about dinoflagellate evolution can potentially be resolved by establishing a robust phylogeny.
To do this, we generated a data set of mitochondrial cytochrome b (cob) and mitochondrial cytochrome c oxidase 1 (cox1) from a broad range of dinoflagellates. Maximum likelihood, maximum parsimony, and Bayesian methods were used to infer phylogenies
from these genes separately and as a concatenated alignment with and without small subunit (SSU) rDNA sequences. These trees
were largely congruent in topology with previously published phylogenies but revealed several unexpected results. Prorocentrum benthic and planktonic species previously placed in different clusters formed a monophyletic group in all trees, suggesting
that the Prorocentrales is a monophyletic group. More strikingly, our analyses placed Amphidinium and Heterocapsa as early splits among dinoflagellates that diverged after the emergence of O. marina. This affiliation received strong bootstrap support, but these lineages exhibited relatively long branches. The approximately
unbiased (AU-) test was used to assess this result using a three-gene (cob + cox1 + SSU rDNA) DNA data set and the inferred tree. This analysis showed that forcing Amphidinium or Heterocapsa to relatively more derived positions in the phylogeny resulted in significantly lower likelihood scores, consistent with
the phylogenies. The position of these lineages needs to be further verified.
Reviewing
Editor: Dr. Martin Kreitman 相似文献
8.
The species of Ganoderma recorded from India as causing diseases of perennial crops are listed, and their host range and taxonomy discussed. Four new hosts of G. lucidum are also reported. A decline in productivity and the death of trees are the main economic impacts due to Ganoderma diseases, and the fungus is identified as a serious pathogen of cash crops, forest plantations and trees in natural forests in the country. Ganoderma diseases have been recorded on 144 hosts in India, the major pathogens being G. lucidum and G. applanatum. G. lucidum has been recorded on 91 hosts, and appears to cause the most widespread diseases. Identification has largely been made from morphological and cultural characters, and the names currently in use should therefore be treated with caution. Cultural methods of disease control are largely inefficient in minimising inoculum pressure and in reducing the disease incidence. Chemical methods in combination with soil amendments form short-term solutions for managing the disease and improving productivity. The immediate priorities for developing an efficient management system for Ganoderma diseases in India are: (1) a thorough understanding of the etiology and epidemiology of the diseases on different hosts, (2) clarifying current ambiguity in species names, (3) assessing the inter-relationships between populations of Ganoderma on different hosts and (4) developing tools for early detection of diseases in important crops. 相似文献
9.
The inhibition of mycelial growth of Lagenidium giganteum by neem oil was lower than that of Metarhizium anisopliae in PYG and Emerson’s YpSs agar media. However, neem oil did not inhibit the mycelial growth of L. giganteum in sunflower seed extract agar medium, but did it inhibit the mycelial growth of M. anisopliae. The minimum inhibitory concentration of neem oil for L. giganteum was higher than that for M. anisopliae. The minimum fungicidal concentration of neem oil in PYG medium was lower than in YpSs for both fungi. The spores of L. giganteum grown in SFE medium could be used with neem oil for vector control. 相似文献
10.
<i>Aspergillus tubingensis</i> Causes Leaf Spot of Cotton (<i>Gossypium hirsutum</i> L.) in Pakistan
Maria Khizar Urooj Haroon Musrat Ali Samiah Arif Iftikhar Hussain Shah Hassan Javed Chaudhary Muhammad Farooq Hussain Munis 《Phyton》2020,89(1):103-109
Cotton (Gossypium hirsutum L.) is a key fiber crop of great commercial
importance. Numerous phytopathogens decimate crop production by causing
various diseases. During July-August 2018, leaf spot symptoms were recurrently
observed on cotton leaves in Rahim Yar Khan, Pakistan and adjacent areas. Infected
leaf samples were collected and plated on potato dextrose agar (PDA) media.
Causal agent of cotton leaf spot was isolated, characterized and identified as
Aspergillus tubingensis based on morphological and microscopic observations.
Conclusive identification of pathogen was done on the comparative molecular
analysis of CaM and β-tubulin gene sequences. BLAST analysis of both sequenced
genes showed 99% similarity with A. tubingensis. Koch’s postulates were followed
to confirm the pathogenicity of the isolated fungus. Healthy plants were inoculated
with fungus and similar disease symptoms were observed. Fungus was re-isolated
and identified to be identical to the inoculated fungus. To our knowledge, this is the
first report describing the involvement of A. tubingensis in causing leaf spot disease
of cotton in Pakistan and around the world. 相似文献
11.
Yang J Nie H Chen L Zhang X Yang F Xu X Zhu Y Yu J Jin Q 《Journal of molecular evolution》2007,64(1):71-79
The theory that Shigella is derived from multiple independent origins of Escherichia coli (Pupo et al. 2000) has been challenged by recent findings that the virulence plasmids (VPs) and the chromosomes share a similar evolutionary
history (Escobar-Paramo et al. 2003), which suggests that an ancestral VP entered an E. coli strain only once, which gave rise to Shigella spp. In an attempt to resolve these conflicting theories, we constructed three phylogenetic trees in this study: a robust
chromosomal tree using 23 housekeeping genes from 46 strains of Shigella and enteroinvasive E. coli (EIEC), a chromosomal tree using 4 housekeeping genes from 19 EcoR strains and 46 Shigella/EIEC strains, and a VP tree using 5 genes outside of the VP cell-entry region from 38 Shigella/EIEC strains. Both chromosomal trees group Shigella into three main clusters and five outliers, and strongly suggest that Shigella has multiple origins within E. coli. Most strikingly, the VP tree shows that the VPs from two main Shigella clusters, C1 and C2, are more closely related, which contradicts the chromosomal trees that place C2 and C3 next to each
other but C1 at a distance. Additionally, we have identified a complete tra operon of the F-plasmid in the genome sequence of an EIEC strain and found that two other EIEC strains are also likely to
possess a complete tra operon. All lines of evidence support an alternative multiorigin theory that transferable diverse ancestral VPs entered diverse
origins of E. coli multiple times during a prolonged period of time, resulting in Shigella species with diverse genomes but similar pathogenic properties.
Electronic Supplementary Material Electronic Supplementary material is available for this article at
and accessible for authorised users.
[Reviewing Editor: Dr. Martin Kreitman]
Jian Yang and Huan Nie contributed equally to this work. 相似文献
12.
The effects of understory dwarf bamboo (Sasa kurilensis) on soil water and the growth of overstory trees were studied in a dense secondary forest of Betula ermanii in northern Japan. Four plots were established in a Betula ermanii forest with Sasa kurilensis in the understory. The Sasa was removed in two of the plots. The annual increment of the trunk diameter for each tree was measured in the first two years from the commencement of the experiment. Soil water potential was similar in the plots following significant rainfall, but was found to be greater in the plot without Sasa between rainfall events. This suggests that the removal of Sasa slows the reduction of soil water after rainfall. The relative growth rate of the trunk diameter of Betula ermanii increased with tree size in all of the plots because taller trees strongly suppressed smaller ones in the dense forest. The growth rates of Betula ermanii were higher in the plots without Sasa. However, the difference in growth rates between all of the plots tended to be smaller in smaller size classes, possibly because smaller trees were strongly suppressed by larger ones, irrespective of the presence/absence of Sasa. Therefore, the removal of Sasa increased soil water and encouraged the growth of larger Betula ermanii in dense forest during the first two years after the Sasa was removed. The present study suggests that Sasa can reduce the growth of larger Betula ermanii in dense forest by limiting available soil water to these trees. 相似文献
13.
Emmanuel Ngulube Chidumayo 《Trees - Structure and Function》2007,21(2):231-238
This study investigated the growth responses to defoliation, fire-exposure and climate factors of a widespread Africana savanna
tree, Bauhinia thonningii Schumacher, at a site in central Zambia. Experimental trees (n = 47) were either exposed to fire (n = 12) in the first half of the dry season or protected from fire (n = 35). Some of the fire-protected trees (n = 12) were subjected to artificial defoliation in two consecutive years. Phenological responses (bud break, leaf flush and
leaf production) to fire-exposure and defoliation were monitored on permanently marked sample shoots over a 2-year period.
Radial tree growth (diameter at 1.3 m above ground) was measured annually over a 7-year period from 1998 to 2005. During the
first two years, defoliation and fire-exposure advanced the onset of bud break and leaf flush but fire-exposed trees produced
significantly less leaves than did trees protected from fire, probably because scorching caused more severe shoot die-back
than is normal. Leaf production was also significantly affected by experimental treatments and their interaction with year.
Although treatments had significant short-term effects on radial growth, previous-year growth significantly influenced current-year
growth, thereby confirming the existence of autocorrelation in the time-series growth data of B. thonningii. The interaction between previous-year growth and climate factors explained a significant proportion (25–40%, P < 0.001) of the variance in annual tree growth. Variogram models predicted that a 2-year manual defoliation treatment would
shorten the longer-term growth cycle while continuous fire-exposure extended the cycle by one year. The results are useful
for the management of savanna trees. 相似文献
14.
Eva Janova Jan Matiasovic Jiri Vahala Roman Vodicka Enette Van Dyk Petr Horin 《Immunogenetics》2009,61(7):513-527
The major histocompatibility complex genes coding for antigen binding and presenting molecules are the most polymorphic genes
in the vertebrate genome. We studied the DRA and DQA gene polymorphism of the family Equidae. In addition to 11 previously reported DRA and 24 DQA alleles, six new DRA sequences and 13 new DQA alleles were identified in the genus Equus. Phylogenetic analysis of both DRA and DQA sequences provided evidence for trans-species polymorphism in the family Equidae. The phylogenetic trees differed from species
relationships defined by standard taxonomy of Equidae and from trees based on mitochondrial or neutral gene sequence data.
Analysis of selection showed differences between the less variable DRA and more variable DQA genes. DRA alleles were more often shared by more species. The DQA sequences analysed showed strong amongst-species positive selection; the selected amino acid positions mostly corresponded
to selected positions in rodent and human DQA genes. 相似文献
15.
The relationship between Litsea and related genera is currently unclear. Previous molecular studies on these taxa using cpDNA and nrITS were unable to produce
well-resolved phylogenetic trees. In this study, we explored the potential of the rpb2 gene as a source of molecular information to better resolve the phylogenetic analysis. Although rpb2 was believed to be a single-copy gene, our cloning results showed that most species examined possessed several copies of these sequences. However, the genetic distance
among copies from any one species was low, and these copies always formed monophyletic groups in our molecular trees. Our
phylogenetic analyses of rpb2 data resulted in better resolved tree topologies compared to those based on cpDNA or nrITS data. Our results show that monophyly
of the genus Litsea is supported only for section Litsea. As a genus, Litsea was shown to be polyphyletic. The genera Actinodaphne and Neolitsea were resolved as monophyletic groups in all analyses. They were also shown to be sisters and closer to the genus Lindera than to the genus Litsea. Our results also revealed that the genus Lindera is not a monophyletic group. 相似文献
16.
Komulainen P Brown GR Mikkonen M Karhu A García-Gil MR O'Malley D Lee B Neale DB Savolainen O 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(4):667-678
A genetic map of Pinus sylvestris was constructed using ESTP (expressed sequence tag polymorphism) markers and other gene-based markers, AFLP markers and microsatellites. Part of the ESTP markers (40) were developed and mapped earlier in Pinus taeda, and additional markers were generated based on P. sylvestris sequences or sequences from other pine species. The mapping in P. sylvestris was based on 94 F1 progeny from a cross between plus-tree parents E635C and E1101. AFLP framework maps for the parent trees were first constructed. The ESTP and other gene sequence-based markers were added to the framework maps, as well as five published microsatellite loci. The separate maps were then integrated with the aid of AFLPs segregating in both trees (dominant segregation ratios 3:1) as well as gene markers and microsatellites segregating in both parent trees (segregation ratios 1:1:1:1 or 1:2:1). The integrated map consisted of 12 groups corresponding to the P. taeda linkage groups, and additionally three and six smaller groups for E1101 and E635C, respectively. The number of framework AFLP markers in the integrated map is altogether 194 and the number of gene markers 61. The total length of the integrated map was 1,314 cM. The set of markers developed for P. sylvestris was also added to existing maps of two P. taeda pedigrees. Starting with a mapped marker from one pedigree in the source species resulted in a mapped marker in a pedigree of the other species in more than 40% of the cases, with about equal success in both directions. The maps of the two species are largely colinear, even if the species have diverged more than 70 MYA. Most cases of different locations were probably due to problems in identifying the orthologous members of gene families. These data provide a first ESTP-containing map of P. sylvestris, which can also be used for comparing this species to additional species mapped with the same markers.Communicated by C. Möllers 相似文献
17.
Masaki Okuda Akihiro Sumida Hiroaki Ishii Valentina P. Vetrova Toshihiko Hara 《Ecological Research》2008,23(5):831-840
We investigated the spatial distribution and growth of the Siberian dwarf pine (Pinus pumila) in a valley–foothill larch–birch (Larix cajanderi–Betula platyphylla as canopy trees) mixed forest of fire origin located in central Kamchatka with the aim of elucidating the ecological features
of P. pumila when it is an undergrowth species in a forest. The spatial distribution of all individuals of all tree species was clumped,
and the spatial distribution of the two canopy tree species did not repulsively affect that of P. pumila (i.e., its establishment site). These results suggest that the regeneration of P. pumila does not depend on canopy gaps. However, the analysis using a growth model indicated that the canopy trees negatively affected
the growth of P. pumila and that the negative effect of L. cajanderi on P. pumila growth was stronger than that of B. platyphylla. The direction of the crown extension of P. pumila was weakly related to the open-space direction. Our results suggest that, although the spatial pattern of establishment of
P. pumila is not repulsed by the distribution of canopy trees, the crown can spread horizontally toward the more sparsely populated
areas of the canopy trees where they may have higher growth rates. 相似文献
18.
The populations of the general microflora (bacteria, actinomycetes and fungi) in the rhizosphere and their corresponding non-rhizosphere
soil samples of Ginkgo biloba L. of two age groups (Group A, <25 years-young trees; Group B, >60 years-old trees) growing under a temperate location of
Indian Himalayan Region (IHR) have been determined. Observations were also made for the diversity, distribution and colonization
of arbuscular mycorrhizal (AM) fungi and occurrence of endophytes in roots of G. biloba. The population of general microflora was found to be higher in the rhizosphere of Group B trees, more clearly reflected
in terms of rhizosphere: soil (R:S) ratios. Contrary to this, per cent colonization and spore densities of AM fungi were higher
in the rhizosphere of Group A trees as compared to the rhizosphere of Group B. AM fungal colonization was observed mostly
in form of loose coils. All the spores detected, belonged to the genus Glomus with five different types. Presence of endophytes (both bacteria and fungi) was observed in the cortical cells of G. biloba roots, more profound in case of Group B trees. Data suggest that, while the species of Glomus dominated the rhizosphere of G. biloba, an inverse correlation exist between the colonization of general microflora and the colonization of AM fungi including endophytes. 相似文献
19.
Fujiwara S Yasui K Watanabe K Wakabayashi T Tsuzuki M Iguchi K 《Marine biotechnology (New York, N.Y.)》2003,5(4):401-407
To study phylogenetic relationships among Okinawan soft corals of the genus Clavularia, the ribosomal internal transcribed spacer sequences of host corals and the 18S rDNA sequences of symbiotic algae were analyzed. The molecular phylogenetic trees of hosts showed that a prostanoid-containing species, Clavularia
viridis, is deeply diverged from other species of Clavularia which do not biosynthesize the prostanoids as the main secondary metabolites. Comparison of their trees suggested poor phylogenetic concordance between hosts and symbionts. 相似文献
20.
During tissue culture of black locust (Robinia pseudoacacia L.), serious problems with plant-associated bacteria led to a reduction of propagation potential in several clones. Four
dominant strains of plant-associated bacteria could be isolated and were assigned to the genera Acidovorax, Dyella, Microbacterium and Sphingomonas. Out of five essential oils tested, thyme and lemongrass oil at a concentration of 0.03% each and 0.015% of both oils in
combination clearly inhibited the growth of these bacteria strains on bacteriologic medium. There were no significant differences
in total bacterial population density when penicillin, thyme and lemongrass oil or thyme plus lemongrass oil were added to
the plant propagation media. The use of lemongrass oil changed the proportion of dominant bacterial strains. 相似文献