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1.
An herbivorous insect, the green oak leaf roller (Tortrix viridana) and one of its host species, pedunculate oak (Quercus robur), were investigated for their genetic variation within and among populations on the basis of mitochondrial, chloroplast, and anonymous markers. Oaks and green oak leaf rollers from 10 oak stands in North Rhine-Westphalia (North-Western Germany) were examined. The genetic variation of pedunculate oaks is much lower within than among populations when assessed using chloroplast gene markers and higher among populations when assessed using anonymous markers. When using mitochondrial and AFLP markers, the genetic variation of the green oak leaf roller populations was higher within than among the populations, which suggests a high gene flow between the populations. Mantel tests on the gene diversities of oaks and the green oak leaf roller yielded a significant negative correlation for both marker types. To sum up, the reasons for the differences in the spatial patterns of the genetic variation of the host and herbivorous insect may be found in their different generation times, mechanisms and capacities for dispersal.The results for the green oak leaf roller revealed a higher migration rate than assumed before which has consequences for the prediction of the dynamics of future outbreak events. 相似文献
2.
Petermann Sarah Otto Sabine Eichner Gerrit Schetelig Marc F. 《Journal of pest science》2021,94(4):1291-1305
Native to Southeast Asia, the spotted wing drosophila (SWD), Drosophila suzukii Matsumura, rapidly invaded America and Europe in the past 20 years. As a crop pest of soft-skinned fruits with a wide range of host plants, it threatens the fruit industry worldwide, causing enormous economic losses. To control this invasive pest species, an understanding of its population dynamics and structure is necessary. Here, we report the population genetics and development of SWD in Germany from 2017–19 using microsatellite markers over 11 different sample sites. It is the first study that examines SWD’s genetic changes over 3 years compared to multiple international SWD laboratory strains. Results show that SWD populations in Germany are highly homogenous without differences between populations or years, which indicates that populations are well adapted, migrate freely, and multiple invasions from outside Germany either did not take place or are negligible. Such high genetic variability and migration between populations could allow for a fast establishment of the pest species. This is especially problematic with regard to the ongoing spread of this invasive species and could bear a potential for developing pesticide resistance, which could increase the impact of the SWD further in the future.
相似文献3.
D. E. L. Cooke T. Jung N. A. Williams R. Schubert W. Oßwald J. M. Duncan 《Forest Pathology》2005,35(1):57-70
The recently discovered oak‐specific fine root plant pathogen Phytophthora quercina is a significant factor in the current phase of European oak decline but its origins and ecology are poorly understood. A genome‐wide analysis of 260 amplified fragment length polymorphism (AFLP) markers was used to examine the genetic diversity of 72 isolates from five oak species at 28 sites in Germany (particularly Bavaria), Italy, France, Hungary and the UK. Within‐site diversity was examined at 16 sites. The limited genetic diversity (within and between sites) and lack of genetic substructuring according to geographic origin or host species suggest the rapid spread of a relatively recently introduced species. Two subgroups were distinguished and these may reflect an initial introduction of isolates of two different genetic backgrounds. The relatively low genetic diversity is probably because of the predominantly inbreeding (homothallic) nature of P. quercina. However, evidence of limited intra‐site diversity, temporal variation and the lack of clonality within the European population suggest that some diversity is being maintained by occasional outcrossing and turnover of a reservoir of long‐lived soil‐borne oospore (sexually derived) inoculum. 相似文献
4.
Madhav Pandey Oliver Gailing Hans H. Hattemer Reiner Finkeldey 《European Journal of Forest Research》2012,131(3):739-746
Knowledge of SGS in plants is vital to understand the ecological and evolutionary dynamics of populations and to plan conservation
strategies. Some of the major factors that can affect spatial genetic structure (SGS) in plants are the level of gene flow,
spatial arrangement and life stages of individuals within populations. Applying six highly variable microsatellite markers,
we investigated the effect of these factors on spatial genetic structure selecting two natural populations of sycamore maple,
which is an insect-pollinated, autotetraploid and an indigenous hardwood species in Germany and in other central European
countries. The two study populations had different shapes (“compact” and “elongated”) and tree densities. Significant SGS
extended to ~180 m in the elongated population and to ~35 m in the compact population. Juvenile plants of the compact population
showed significant SGS up to 40 m. Estimate of Sp statistic in high-density population was almost double of that in the population
with low density. Gene dispersal distance in the low-density population was about 9 times higher than in the population with
high density. The similar level of significant SGS in both adult and juvenile plants suggested minimal or no effect of life
stages of individuals on SGS in the sycamore maple population. The data presented in this study can provide guidelines for
seed collection and to establish populations for the conservation and management of genetic resources of the species. 相似文献
5.
Romero-Severson Jeanne Aldrich Preston Feng Yi Sun Weilin Michler Charles 《New Forests》2003,26(1):43-49
Chloroplast DNA (cpDNA) variation was examined in 48 northern red oaks at 14 sites representing contrasting glacial histories and age structures within the state of Indiana in the United States. PCR-RFLP of three intergenic regions revealed five haplotypes. Haplotype I was common to seven sites and was the most frequent (17 trees). Haplotype II was common to five sites and was nearly as frequent as haplotype I (16 trees). Haplotypes III, IV and V were equally infrequent and did not occur together. Genetic diversity resided among rather than within populations (GST = 0.73 ± 0.14). This preliminary survey shows that cpDNA diversity will be a useful tool for the investigation of ancient seed dispersal patterns in northern red oak. 相似文献
6.
7.
《Scandinavian Journal of Forest Research》2012,27(3):211-218
Abstract Variations in defensive and some other leaf traits were studied in a population of an oak species, Quercus dentata Thunberg, in northern Japan, with reference to attacks by ectophagous herbivores and leafminers. The oak population showed substantial individual variations in concentrations of total phenolics and condensed tannins, nitrogen content, trichome density, leaf area and budburst timing. With the exception of leaf mass per area, which showed a positive relation with leaf toughness and a negative relation with water content, no significant relation was observed between the plant traits studied, suggesting an absence of trade-off or linkage between them. The oaks also showed substantial individual variations in leaf area loss by ectophagous herbivores, densities of major leafminers (Phyllonorycter and Stigmella species) and survival of Phyllonorycter sap-feeding larvae. The density of trichomes showed a significant, negative relation with leaf area loss by ectophagous herbivores, but significant, positive relations with densities of some leafminers. The other leaf traits seldom showed significant relations with herbivore densities or survival. In this oak population, these traits may not have enough variations to be reflected in the abundance and performance of herbivores. 相似文献
8.
In natural plant populations, leaf polyphenols show high intraspecific variation that occurs both temporally and spatially. Leaf phenolics may be induced by diverse ecological factors such as light, nitrogen availability or herbivory attack. Both light and nitrogen availability can show spatial structure in forested stands, meaning that they each have a high degree of autocorrelation, which can determine the appearance of spatial structure in leaf polyphenols. However, the availability of these resources may be drastically changed by forest disturbance, and little is known about the effect of forest disturbance on the spatial pattern and scale of leaf secondary compounds. We hypothesise that the spatial structure of leaf polyphenols in understory vegetation will disappear due to forest harvesting, because these compounds depend on light availability, yet it will remain unaltered for those compounds that either depend on the availability of other resources or are under major genetic control. The study was performed in young pedunculate oak (Quercus robur) populations growing either under a pine canopy (Pinus pinaster) stand or in a pine harvested stand in NW Spain. The spatial structures of green and senescent leaf polyphenols, tannins, non-tannin polyphenols and nitrogen were analysed in both stands using geostatistical analysis. The spatial structures observed for green and senescent leaf polyphenols and tannins in the forested stand disappeared in the harvested stand. However, non-tannin polyphenols, as well as nitrogen, showed spatial structure in both stands. Understanding these changes may be important for the successful recovery of native oak populations growing under pine forests in NW Spain, one of the priorities of the local government. Our results showed that changes in the concentration of leaf secondary compounds after disturbance may be accompanied by differences in their spatial properties, which may have important consequences for ecosystem function. 相似文献
9.
Taxus wallichiana is one of the most important medicinal tree species of the Himalayan region. Leaf and bark of the species yield an important
drug called taxol, which is used for treatment of many types of cancer. There is a serious threat to the existence of the
species due to over exploitation in its native habitat. Adequate information on the nature and the extent of genetic diversity
in this important species is required for developing suitable strategy for its conservation. Random amplified polymorphic
DNA (RAPD) and amplified fragment length polymorphism (AFLP) were used to assess genetic variation in nine natural populations
of T. wallichiana from western part of the Himalayan ranges. Both the markers revealed low genetic diversity in these populations. Average
heterozygosity for AFLP and RAPD were 0.3715 and 0.3072, respectively. ΦST values derived from molecular variance were 0.0855 and 0.1005 for AFLP and RAPD, respectively, whereas the corresponding
GST values were 0.1796 and 0.2140. Most part of the genetic variation was present within the populations. However, between population
variation was low but statistically significant, which suggested that the sampled populations might not constitute a single
panmictic population. Cluster analysis and Mantel’s correlation revealed that genetic differentiation broadly followed geographic
distribution of the populations. T. wallichiana thus urgently needs to be conserved using both in situ and ex situ conservation approaches. 相似文献
10.
In the United States, diseased oaks (Quercus species) exhibit tip blight, branch and stem cankers, and dieback often attributed to Diplodia species or related fungi. Emergence of Diplodia corticola as a pathogen of European oaks, and reports of this fungus in the eastern and western United States, prompted re‐examination of strains from Wisconsin. These had been obtained in the late 1990s and early 2000s and previously identified only as Diplodia species. Nuclear ribosomal ITS sequences were obtained from the Wisconsin strains and analysed with other sequences from GenBank. Wisconsin strains confirmed as D. corticola were from northern red oak (Q. rubra), black oak (Q. velutina), white oak (Q. alba) and bur oak (Q. macrocarpa). Other strains from oaks in Wisconsin were D. mutila and D. seriata. Wound inoculation of northern red, white and bur oak seedlings with D. corticola in a greenhouse resulted in shoot death and stem lesions, from which the pathogen was reisolated. We conclude that D. corticola has been present in the northcentral United States for at least two decades and report two previously unrecognized hosts of this pathogen: white oak and bur oak. The roles of D. corticola, related fungi and influences of other environmental factors in deterioration of oak health in North America merit additional investigation. 相似文献
11.
Nuts are heavy and nutritious seeds that need animals to be successfully dispersed. Most studies address nut removal by a single animal species once seeds fall onto the ground. However, nuts are also accessible before the seed drop and usually to a wide guild of seed foragers. This study examines the factors controlling arboreal seed removal in oak-beech forests within the whole guild of nut foragers. We found that seed-dispersing rodents (Apodemus sylvaticus) were the main acorn removers in the oaks (up to 3.75 m height), with a rapid seed encounter and a high removal rate. However, rodents did not climb the beech trees, probably due to their smoother bark in comparison to oak bark and/or the lower nutritional value of beechnuts with regard to acorns. Jays (Garrulus glandarius) were more abundant in oak stands (both dense and scattered) and clearly preferred acorns to beechnuts whereas nuthatches (Sitta europaea) were more abundant in beech stands and preferred beechnuts to acorns. Non-storing birds such as great tits (Parus major) also removed acorns and beechnuts, especially in the stands where oaks are dominant. Jays and rodents preferred sound seeds over insect-infested seeds but such a preference was not found for nuthatches. This study highlights that pure beech stands showed a reduced guild of arboreal nut foragers in comparison to oak stands. This different guild could probably affect the spatial patterns of seed dispersal, with a proportionally higher number of long dispersal events for acorns (mostly jay-dispersed) than for beechnuts (mostly nuthatch-dispersed). Long-distance dispersal of beechnuts (by jays) is determined by the presence of other preferred species (oaks) and their frequency of non-mast years. Seed location in different habitats strongly determines the contribution of different arboreal removers (including climbing rodents) and their removal speed, leading to a differential seed fate that will eventually affect tree regeneration. As nuthatches are sedentary birds, it is important to maintain old and dead trees where they can breed (crevices), forage (arthropods) and store seeds in order to favor beechnut dispersal and gene flow. By maintaining or favoring oak trees within beech stands we will ensure a wider guild of arboreal nut dispersers. 相似文献
12.
The effects of root damage associated with Phytophthora cinnamomi on water relations, biomass accumulation, mineral nutrition and vulnerability to water deficit were investigated in pedunculate oak (Quercus robur), red oak (Quercus rubra) and holm oak (Quercus ilex) saplings over two years. Comparison was made with sweet chestnut (Castanea sativa), a susceptible species to infection by P. cinnamomi, and with a resistant hybrid chestnut (Castanea crenata × C. sativa). Trees were inoculated in 1998 and were subjected to water shortage in 1999. All inoculated sweet chestnuts died before the application of water shortage. Hybrid chestnut, pedunculate oak and red oak displayed low root susceptibility to P. cinnamomi. In these species, water relations, aerial growth and mineral nutrition were slightly affected by inoculation. By contrast, holm oak was the most susceptible oak species to P. cinnamomi as inoculated well‐watered trees displayed the highest root loss (67%) and a 10% mortality. Root loss was associated with a decrease in predawn leaf water potential, a 61% reduction in stomatal conductance, a 55% reduction in aerial biomass, a decrease in leaf carbon isotope discrimination and reduced leaf N and P contents in comparison with controls. In hybrid chestnut and pedunculate oak, water shortage resulted in a similar decrease of predawn leaf water potential, stomatal conductance and aerial biomass in inoculated and non‐inoculated trees. In red and holm oaks, soil volumetric water content of inoculated trees subjected to water shortage remained high. The effects observed in those trees were similar to those of inoculated well‐watered trees and were probably the result of root infection only. 相似文献
13.
Spatial pattern of recruitment is an important factor influencing population dynamics of plant communities. The spatial pattern is determined by seed dispersal and by the spatial variability of germination and initial survival. In the process of forest expansion following farmland abandonment, mid- and late-successional species are often dispersed in pioneer forests by birds. This could result in an aggregated spatial pattern of seeds that could influence the dynamics of these species in mixed pioneer forests. In the sub-Mediterranean area, mid- and late-successional species such as Quercus pubescens (downy oak) and Fagus sylvatica (European beech) are expected to replace pioneer Pinus species. Using a point sampling method we demonstrated that beech and oak seedlings (height <2 m) have a clumped distribution in the understorey of pine. This could result from an aggregated dispersal by jays (dispersal effect) or from preferential recruitment in particular habitats (habitat effect). To test these hypotheses we proposed a statistical analysis of spatial patterns of regeneration of beech and oak. Ground cover variables (i.e. cover by rock outcrops, herbs, box shrubs, mosses or pine) did not differ significantly around seedlings as compared with random sample plots. Likewise, clumped seedlings had growth similar to isolated seedlings, thus refuting the hypothesis of preferential location in the most favourable microsites. Aggregated dispersal seems to be involved in the process of regeneration. Since beech and oak seedlings have contrasting ecological demands, we discuss the implication of this pattern for the replacement dynamics of pine by these species. 相似文献
14.
Akira Ueda 《Journal of Forest Research》2000,5(3):169-174
A comparative study of pre- and post-dispersal damage to the acrons of two oaks,Quercus serrata Thunb. andQ. mongolica Fischer, was done over 3 years in a species-rich deciduous forest in central Japan. The numbers of acorns bored into by moth
larvae and byKobuzo rectirostris (Roelofs) was low and relatively uniform each year for both oak species, but the numbers bored into byCurculio spp. varied from year to year. The proportions of acorns attacked were independent of the density of acorns produced for
both oak species. The proportions of the dispersed acorns of both oak species on the forest floor that disappeared between
autumn and spring were less than 27%, and were lower for species in the stand that belong to family Fagaceae. However, by
the next summer, most dispersed sound acorns had been infested by moths that specialized on post-dispersal acorns. 相似文献
15.
M. Garbelotto 《Forest Pathology》2012,42(1):8-13
Variation in virulence was examined among isolates of Phytophthora ramorum from epidemiologically important or infectious (non‐oak) and transmissive dead‐end (oak) hosts from North America. Twelve isolates representative of the genetic, geographic and host range of P. ramorum in the western United States were inoculated on leaves of Umbellularia californica (bay laurel or bay) and stems of Quercus agrifolia (coast live oak). In spite of extreme genetic similarity among the isolates employed, and even within the same genotype, significant differences in lesion size were measured, suggesting virulence in this pathogen is also controlled by epigenetic factors. A strong positive correlation between lesion size on bay laurel and coast live oak provides experimental evidence P. ramorum is a generalist pathogen that lacks host specificity. Isolates from non‐transmissive oaks were significantly less pathogenic both on oaks and bays than isolates from infectious hosts. These results are essential to further our understanding of the epidemiology and evolutionary potential of this pathogen. A quantitative differential in virulence of isolates from hosts with different epidemiological roles has been described for many animal diseases, but is a novel report for a plant disease. 相似文献
16.
Ana Juan Michael F. Fay Julio Pastor Rocío Juan Inmaculada Fernández Manuel B. Crespo 《European Journal of Forest Research》2012,131(3):845-856
The Spanish populations of Juniperus oxycedrus subsp. macrocarpa are restricted to coastal dune habitats of the Mediterranean and Atlantic coasts. Here, we investigate the genetic structure
in this taxon and the possible existence of detailed phylogeographic structure associated with the Strait of Gibraltar using
data from amplified fragment length polymorphism (AFLP) and plastid markers for 14 populations in three regions: Andalusia,
the Valencian Community and the Balearic Islands. Principal coordinate analysis (PCOA) data revealed a lack of clear genetic
structure in J. oxycedrus subsp. macrocarpa based on AFLP. The highest AFLP genetic diversity was found in Andalusia. Plastid markers revealed 14 haplotypes, only two
of them were shared among the regions. Andalusian populations had the highest number of exclusive haplotypes. Our results
support Andalusia as a reservoir of genetic diversity for J. oxycedrus subsp. macrocarpa, and, as for other gymnosperms, this area could be considered as a genetic refugium. The frequent presence of common and
exclusive haplotypes in Andalusia might indicate the colonisation of the Spanish Mediterranean coast from the Atlantic populations.
Colonisation of these new areas could be promoted by biological factors, such as the existence of long-lived individuals or
potential for seed dispersal. Finally, the Strait of Gibraltar did not constitute a natural barrier to the expansion of this
species along the coast, as identical haplotypes are found on the Atlantic and Mediterranean coasts. 相似文献
17.
Ing. J. Novotný CSc. Doc. Dr. J. Patočka DrSc. Doc. Dr. I. Hrdý DrSc. Dr. J. Vrkoč CSc. 《Journal of pest science》1990,63(7):125-129
In the period from 1986 to 1988 the synthetic sexual pheromone ofTortrix viridana L. and different types of traps were investigated in Slovakian oak forests. The dependence of male numbers per trap on the forest type groups was studied parallely as well as the attraction of pheromones for other moth species was tested, too. The pheromon TV83 (Z11-14: Ac+Z11-14: OH, 9∶1, 50 μg) and unsticky plastic trap with DDVP called “Mushroom” showed the highest effectivity. The pheromon monitoring confirmed the theory that the pest prefers the biotops with dominance ofQuercus pubescens andQ. robur. The optimum of pest was bound to forest type groups Carpineto-Quercetum und Ulmeto-Fraxinetum carpineum. The minimal number of other moth species was observed in traps with pheromons TV83 (?SFR) and Hoechst (FRG). 相似文献
18.
Chadwick Dearing Oliver E.C. Burkhardt Daniel A. Skojac 《Forest Ecology and Management》2005,210(1-3):393-414
Red oaks – cherrybark oak (Quercus pagoda Raf.), willow oak (Quercus phellos L.), water oak (Quercus nigra L.), and Nuttall oak (Quercus texana Buckley; aka: Quercus nuttallii Palmer) – are not regrowing in Mississippi Delta river floodplain forests in the southeastern United States in sufficient numbers to sustain the former species composition and timber and wildlife values. Even if vigorous red oak reproduction becomes established, partial harvesting that does not remove the taller trees will suppress understory red oak height growth more than it will suppress height growth of such other species as sugarberry (Celtis laevigata Willd.), American elm (Ulmus americana L.), cedar elm (Ulmus crassifolia Nutt.), swamp dogwood (Cornus foemina Mill.), green ash (Fraxinus pennsylvanica Marshall), and sweetgum (Liquidambar styraciflua L.). Consequently, the red oaks in these partially harvested stands become increasingly suppressed and probably die; and there is a shift in species composition to the other species. In addition to ensuring vigorous oak reproduction, silvicultural clearcutting or rapid removal of the residual trees following shelterwood or seed tree harvesting to provide full sunlight is needed to ensure red oaks become a dominant part of these future river floodplain stands. 相似文献
19.
Regeneration by seeds for cork oak (Quercus suber) and companion oaks (holm oak Quercus ilex and downy oak Quercus pubescens) is likely to be poor in the fire-prone Maures massif (southern France) but the causes are poorly known. Our objective was to assess the effective recruitment for these three oak species and their temporal pattern of recruitment, in order to determine the main limitation factors and the regeneration window of each species. We studied oak recruits (height <3 m) in naturally regenerated populations according to a gradient of fire recurrence and in five main vegetation types including shrublands and mixed mature woodlands. Fire recurrence was the main explanatory factor of oak recruitment, either directly or through vegetation type and microsite characteristics. The results indicate nil to low recruitment for holm oak and downy oak in shrublands, especially those recurrently burned and dominated by Cistus species. Cork oak recruited better than the other oaks in medium and high shrublands dominated by Erica arborea. In contrast, recruitment was high for holm and downy oak in mixed oak stands and mixed pine-oak stands that have not burned for decades. Microsite conditions such as coverage by litter and shrubs influenced oak recruitment, whereas landscape configuration and stand basal area had no influence. Our results suggest that strategic shrub-clearing, oak planting and protection of mixed oak woodlands as seed sources would help maintaining oak populations in the woodland–shrubland mosaic. 相似文献
20.
Fine root dynamics of oak saplings in response to Phytophthora cinnamomi infection under different temperatures and durations 
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下载免费PDF全文 The belowground effects of Phytophthora cinnamomi on 1‐year‐old saplings of two common oak species in mid‐Atlantic US forests, white (Quercus alba) and red oak (Q. rubra), were examined after incubation in pathogen‐infested soilless potting mix. Fine root lengths (0–1.5 mm in diameter) of both oak species were quantified after incubation at successive 30‐day intervals up to 300 days, for a total of 10 incubation periods. In addition, colony‐forming units (CFU) of P. cinnamomi were quantified after white oak saplings were incubated in infested soilless potting mix at different temperature/duration combinations that reflect soil conditions present in the mid‐Atlantic United States. Impact of P. cinnamomi on fine root lengths of red and white oak saplings varied considerably over time. Significant periods of fine root loss occurred primarily during spring, when bud break and leaf flush began for both oak species. Red oaks had 17% fine root loss on average, while white oaks appeared more resistant to P. cinnamomi infection with a 2% decrease in fine roots over the course of the experiment. Phytophthora cinnamomi CFU declined significantly with exposure to all incubation temperatures except 8°C. This was in contrast to in vitro experiments, where the optimum temperature for mycelial growth was determined to be 21°C and above. Significant fine root loss caused by P. cinnamomi depended on plant phenology and the oak species tested. Extreme soil temperatures have a significant adverse impact on temporal changes of P. cinnamomi population. 相似文献