Quercus arkansana(Arkansas oak)is at risk of becoming endangered,as the total known population size is represented by a few isolated populations.The potential impact of climate change on this species in the near futur...Quercus arkansana(Arkansas oak)is at risk of becoming endangered,as the total known population size is represented by a few isolated populations.The potential impact of climate change on this species in the near future is high,yet knowledge of its predicted effects is limited.Our study utilized the biomod2 R package to develop habi-tat suitability ensemble models based on bioclimatic and topographic environmental variables and the known loca-tions of current distribution of Q.arkansana.We predicted suitable habitats across three climate change scenarios(SSP1-2.6,SSP2-4.5,and SSP5-8.5)for 2050,2070,and 2090.Our findings reveal that the current suitable habitat for Q.arkansana is approximately 127,881 km^(2) across seven states(Texas,Arkansas,Alabama,Louisiana,Mississippi,Georgia,and Florida);approximately 9.5%is encompassed within state and federally managed protected areas.Our models predict that all current suitable habitats will disap-pear by 2050 due to climate change,resulting in a northward shift into new regions such as Tennessee and Kentucky.The large extent of suitable habitat outside protected areas sug-gests that a species-specific action plan incorporating pro-tected areas and other areas may be crucial for its conserva-tion.Moreover,protection of Q.arkansana habitat against climate change may require locally and regionally focused conservation policies,adaptive management strategies,and educational outreach among local people.展开更多
Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpou...Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpounded tracts of bottomland hardwood forest flooded throughout the winter months to provide habitat for overwintering waterfowl.Artificial flooding of GTRs alters the forest composition due to flood frequency,depth,and duration in combination with slight changes in topography.To evaluate the effect of elevation gradients,soil properties,and management techniques in the overstory species composition and red oak(Quercus spp.)species abundance,we inventoried 662 plots across 12 independent GTRs in eastern Arkansas.In the lower elevations ranging from 50.98 to 54.99 m above sea level,the importance value index(IVI)was highest for nuttall oak(Quercus texana)and overcup oak(Quercus lyrata),whereas IVI shifted to cherrybark oak(Quercus pagoda)in the higher elevations ranging from 54.99 to 58.00 m.Alpha diversity did not differ by elevation gradient,soil property,or management technique within GTRs.Beta diversity,using non-metric multi-dimensional scaling(NMDS)analysis,indicated site-specific variability significantly correlated with the environmental predictors,including elevation(R^(2)=0.57),easting(R^(2)=0.47),soil texture(R^(2)=0.21),and pH(R^(2)=0.12).Red oak species-specific mixed-effects modeling of abundance response using Poisson distribution suggested an inverse correlation of nuttall oak and a direct correlation of cherrybark oak abundance with elevation.However,willow oak(Quercus phellos)abundance was not significantly affected by elevation but was by silt loam soil texture and restoration management techniques.These findings will aid management efforts to reduce the dominance of less desirable species that are prominent under specific environmental conditions and promote the dominance of more desirable species.Ultimately GTR sustainability is increasingly important amid the unpredictable impacts of climate change on the preferred red oak species that are economically,ecologically,and environmentally valuable to the sustaining economy of the local community and managing habitats for wildlife.展开更多
Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines.In the present study,the aroma compounds were analyzed from the‘Merlot’dry red wines,which were fermen...Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines.In the present study,the aroma compounds were analyzed from the‘Merlot’dry red wines,which were fermented in two types of fermenters(stainless steel tank and rotated oak barrel)and aged in six types of oak barrels(three geographic origins×two toasting degrees)for different time(0,3,6 and 9 months,respectively).Results showed that 30 volatiles were associated with barrels and increased during oak aging.The fermenters could influence the intensities of the toast,leathery,smoky,fruity,floral and caramel aromas.The concentration of whisky lactone,eugenol,cis-isoeugenol,and the intensities of the toast and spicy aromas were highest in the wines aged in American oak and were lowest in the wines aged in French oak barrels.The concentrations of guaiacol,syringol,trans-isoeugenol,furfural alcohol,vanilla,cis-whisky lactone enabled the medium toasting barrels to be distinguished from the light toasting ones.The compounds originating from the barrels could be used to distinguish the types of different barrels,but the other general grape-derived and fermentation-derived volatiles could not.The fermenters,oak species and toasting degrees of the barrels all had significant effects on the aroma profiles of the aged‘Merlot’dry red wines,but the influence of the geographic origin was not obvious.展开更多
Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, ...Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, where we sampled soils in areas that were classified by fire severity: low (LS), high (HS) and medium severity (MS), and unburned (UB), which served as the control. In each severity class, 25 transect points were randomly selected for measurement. Around each transect plot center, 3 soil samples were selected randomly and soils collected from the 0 to 20 cm depth were combined into a composite sample that was used in laboratory analysis to represent conditions at that point. Plots in the UB and LS fire classes had similar soil conditions and had higher values of factors such as saturated moisture, organic carbon, carbon dioxide, and silt and clay content. In contrast, plots in the HS and MS fire severity classes were clustered in the positive direction along the first axis that represented gradients in soil acidity, electrical conductivity, cation exchange capacity, accessible phosphorus, accessible potassium, bulk density, and sand. Soil attributes were similar in areas of HS and MS fire severity classes, whereas soil conditions in the LS class and UB controls were most similar. Fire in the LS areas either did not significantly alter the physicalchemical soil properties and microbial basal respiration, or soils were able to recover quickly after being burned.展开更多
The need for reforestation in cork oak (Quercus suber L.) areas is challenged by difficulties. Principal among these is herbivory of young plants, vegetative competition, and slow growth rates of cork oak seedlings....The need for reforestation in cork oak (Quercus suber L.) areas is challenged by difficulties. Principal among these is herbivory of young plants, vegetative competition, and slow growth rates of cork oak seedlings. We evaluated the early development of cork oak seedlings treated using tree shelters and mulching in northwestern Tunisia. We tested three tree shelter treatments (non-vented, vented, and control) to shield seedlings from animal damage and five mulch types to control competing vegetation (Italian Stone Pine, Lentisk, combination of Italian Stone Pine and Lentisk (organic mulches), gravel (inorganic mulch) and no mulch). At the end of the two-year experiment, sheltered seedlings were 89-99% taller than unshelteredseedlings and had higher numbers and lengths of shoot growth flushes. In contrast, both stem diameter growth and dry weight biomass (from samples extracted after two years) were significantly reduced inside tree shelters. Root-to-shoot ratio was not significantly different in sheltered vs. unsheltered seedlings, suggesting that tree shelters do not adversely affect this parameter. Mulching alone did not favour growth, but could be beneficial when combined with tree shelters. The combination of vented tree shelters and gravel mulch was the most effective treatment for promoting diameter, height and stem volume growth.展开更多
We assessed the effect of mulching and tree shelters on the establishment and early growth of zeen oak(Quercus canariensis Willd.) during the first 4 years after planting in Northwestern Tunisia. Five mulch types(Ital...We assessed the effect of mulching and tree shelters on the establishment and early growth of zeen oak(Quercus canariensis Willd.) during the first 4 years after planting in Northwestern Tunisia. Five mulch types(Italian Stone Pine(Pinus pinea L.), Lentisk(Pistacia lentiscus L.),and a combination of Italian Stone Pine and Lentisk(organic mulches), gravel(inorganic mulch) and control), and three tree shelter types(non-vented and vented tree shelters, and control) were tested. An increase in the number of internodes occurred under the gravel mulch, while a reduction in survival was found for the lentisk mulch. Tree shelters had no effect on survival, but increased mean height growth and reduced mean diameter growth during the 4 years(excepting a non-significant effect for vented tree shelter at year four). Comparison of the annual shoots and growth units(GU) between sheltered and unsheltered plants according to year of formation revealed two growth phases. In first phase, shoots were totally or partially inside the shelters; mean length of annual shoots and GU were greater for sheltered plants. The second phase was characterized by shoots emerging from shelters; mean length of annual shoots and GU were similar for all plants, with or without tree shelters. Results suggest that the use of tree shelters, particularly vented shelters, could contribute to the improvement of the artificial regeneration of zeen oak.The use of mulching alone or in combination with tree shelters did not improve zeen oak performance in the field.展开更多
Background:Mature oak(Quercus spp.)and hickory(Carya spp.)trees are gradually being replaced by more shadetolerant tree species across the eastern U.S.,likely due to fire suppression and increased precipitation.Oaks a...Background:Mature oak(Quercus spp.)and hickory(Carya spp.)trees are gradually being replaced by more shadetolerant tree species across the eastern U.S.,likely due to fire suppression and increased precipitation.Oaks and hickories are highly valuable to wildlife;therefore,studying their mortality patterns can provide information on the longevity of habitat quality for many animal species.Oak mortality has most often been studied following large oak decline events,but background mortality rates in forests with aging oak and hickory canopies warrant equal attention,especially in the context of widespread oak and hickory regeneration failure.Methods:We studied background mortality rates of five oak and one hickory species over a 23–25 year time period(1993–1995 to 2018),using 821/20th hectare permanent plots on the Marietta Unit of the Wayne National Forest in southeastern Ohio.We calculated mortality rates based on remeasurement of individual trees for white oak(Quercus alba),chestnut oak(Quercus montana),northern red oak(Quercus rubra),black oak(Quercus velutina),scarlet oak(Quercus coccinea),and pignut hickory(Carya glabra).For each of these species other than scarlet oak,we also modeled the relationships of mortality probability with a priori topographic,soil,stand structural,and individual tree covariates,using a mixed-effects logistic regression framework.Results:The species with the highest mortality rate was scarlet oak(61.3%),followed by northern red oak(41.4%),black oak(26.7%),pignut hickory(23.9%),white oak(23.4%),and chestnut oak(19.1%).In our models,northern red oak mortality was associated with more mesic slope positions,shallower solums,more acidic soils,and older stand ages.Pignut hickory and chestnut oak mortality rates were associated with higher basal areas on the plot,while white oak mortality showed the opposite pattern.Conclusions:Our data suggest that red oak subgenus trees in mature forests of our area will become increasingly uncommon relative to white oak subgenus trees,as the result of higher mortality rates likely related to the shorter lifespans of these species.Particularly vulnerable areas may include more mesic topographic positions,shallower or more acidic soil,and older stands.Since maintaining oak subgenus diversity is beneficial to wildlife diversity in the eastern U.S.,managers in areas with extensive mature mixed-oak forests could choose to favor the red oak subgenus when conducting silvicultural treatments.展开更多
The relationships between plant organs and root hydrological traits are not well known and the question arises whether elevated CO2 changes these relationships. This study attempted to answer this question. A pseudo-r...The relationships between plant organs and root hydrological traits are not well known and the question arises whether elevated CO2 changes these relationships. This study attempted to answer this question. A pseudo-replicated experiment was conducted with two times 24 American elm (Ulmus americana L.) and 23 and 24 red oak (Quercus rubra L.) seedlings growing in ambient CO2 (around 360 μmol.L^-1) and 540 ± 7.95 μmol.L^-1 CO2 in a greenhouse. After 71 days of treatment for American elm and 77 days for red oak, 14 American elm and 12 red oak seedlings from each of the two CO2 levels were randomly selected in order to examine the flow rate of root xylem sap, root hydraulic conductance, total root hydraulic conductivity, fine root and coarse root hydraulic conductivity. All seedlings were harvested to investigate total plant biomass, stem biomass and leaf biomass, leaf area, height, basal diameter, total root biomass, coarse root biomass and fine root biomass. The following conclusions are reached: 1) plant organs respond to the elevated CO2 level earlier than hydraulic traits of roots and may gradually lead to changes in hydraulic traits; 2) plant organs have different relationships with hydraulic traits of roots and elevated CO2 changes these relationships; the changes may be of importance for plants as means to acclimatize to changing environments; 3) biomass of coarse roots increased rather more than that of fine roots; 4) Lorentzian and Caussian models are better in estimating the biomass of seedlings than single-variable models. Key words American elm, biomass, elevated CO2, modeling, red oak, root hydraulic traits展开更多
Background:The relationship between physiological age of parental trees and lifespan of clonal offspring is unclear.White oak(Quercus fabri Hance)has a high sprouting capability after harvest,with the regenerated spro...Background:The relationship between physiological age of parental trees and lifespan of clonal offspring is unclear.White oak(Quercus fabri Hance)has a high sprouting capability after harvest,with the regenerated sprouts being typical clonal individuals.To determine whether regenerated sprouts undergo rapid senescence compared with the parent,the senescence levels of 5-,10-,20-and 40-year-old regenerated stump sprouts in a natural forest were evaluated.The antioxidative abilities and transcriptomes in these leaves and shoots were compared.Results:Older regenerated sprouts still had robust antioxidative systems,with 40-year-old sprouts having lower peroxidation product levels but similar antioxidative enzyme activity levels compared with 5-year-old sprouts.Older leaves had greater transcriptional activities in pathways related to cell growth and division than younger leaves.However,older sprouts had some unhealthy characteristics,such as increased base excision repair levels and upregulated phagosome,proteasome and glycerophospholipid metabolism pathways in 40-year-old leaves,which indicates that DNA damage and tissue remodeling occurred more frequently than in younger leaves.Additionally,plant-pathogen interactions and MAPK signals pathways were upregulated in older shoots,which indicates that older shoots suffered from more pathogen-related biotic stress.Conclusions:The 40-year-old sprouts still had the same vitality level as the 5-year-old sprouts,although the former had some unhealthy characteristics.We conclude that during their first 40 years of growth,regenerated stump sprouts do not begin to senesce,and that physiological age of parental trees does not significantly affect the lifespan of its clonal offspring.展开更多
This study was conducted to determine the parent-off spring genetic structure of the pedunculate oak(Quercus robur L.),sessile oak(Q.petraea[Matt.]Liebl.)and their hybrids.Forty half-sib Quercus families and their mat...This study was conducted to determine the parent-off spring genetic structure of the pedunculate oak(Quercus robur L.),sessile oak(Q.petraea[Matt.]Liebl.)and their hybrids.Forty half-sib Quercus families and their maternal trees originating from one tree stand in southern Lithuania were analyzed using SSR and RAPD markers.Based on a preliminary study of leaf morphological traits,the individuals separated into six groups.The studied halfsib oak families were also compared for allelic diversity,including group variations;genotypic structure;genetic diversity;and the degree of genetic subdivision and diff erentiation.The level of genetic variation and subdivision was lower in the hybrid families than in the families of the parental species.Genotypic analysis of the half-sibling off spring showed the asymmetric nature of interspecifi c hybridization processes of pedunculate and sessile oaks in mixed stands.展开更多
In the present study, we tested the effect of amino acids on secondary somatic embryogenesis of Moroccan cork oak (Quercus suber L.). Secondary mature and immature somatic embryos were obtained from primary somatic em...In the present study, we tested the effect of amino acids on secondary somatic embryogenesis of Moroccan cork oak (Quercus suber L.). Secondary mature and immature somatic embryos were obtained from primary somatic embryos cultured in N30K medium supplemented with nineteen amino acids. Stimulation of embryogenesis was dependent on the type and concentration of amino acid in the medium. Thus, L-glutamine and L-asparagine at 3.42 mM have been proved to be the most favorable for the formation of functional somatic embryos and the induction of secondary somatic embryos.展开更多
The canopy net photosynthesis rate of Mongolian oak (Quercus mongolica) tree species that are dominant in East Asia and Korea is estimated with empirical models derived from field experimental data obtained from the N...The canopy net photosynthesis rate of Mongolian oak (Quercus mongolica) tree species that are dominant in East Asia and Korea is estimated with empirical models derived from field experimental data obtained from the Nam-San site in Seoul, Korea for the growing period from early May to late October in 2010. The empirical models include the attenuation function of photosynthetic photon flux density (PPFD) (r2 = 0.98-0.99, p r2 = 0.99, p < 0.001) derived from the measured data at several levels within the canopy. The incident PPFD at each level within canopy significantly varies diurnally and seasonally due to the seasonal variation of the total plant area index (TPAI = leaf area index + wood silhouette area index) and the light shielding effect of light path-length through the canopy in association with the variation of solar elevation angle. Consequently, a remarkable seasonal variation of the total canopy net photosynthesis rate of Q. mongolica forest stand is found for its growing period. The PPFD exceeding 1000 μmol m-2·s-1 is found to cause the decrease of net photosynthesis rate due to the thermal stress in the early (May) and late (September) growing period. During the whole growing season, the estimated total canopy net photosynthesis rate is found to be about 3.3 kg CO2 m-2.展开更多
Background: Within the framework of close-to-nature forestry, oak forest(Quercus robur, Q. petraea) regeneration techniques that consider both silvicultural and nature conservation demands have become a very important...Background: Within the framework of close-to-nature forestry, oak forest(Quercus robur, Q. petraea) regeneration techniques that consider both silvicultural and nature conservation demands have become a very important issue.While there are many experimental and local studies that aim at disentangling the relationships between different environmental and silvicultural factors and the success of oak regeneration, systematic supra-regional studies at the greater landscape level are missing so far.Against this background, the first objective(a) of this study was to present an efficient and sufficiently accurate sampling scheme for supra-regional forest regrowth inventories, which we applied to young oaks stands. The second, and major, objective(b) was to identify the crucial success factors for high-quality oak forest regeneration in northwest Germany.Results: Objective(a): Factors that have been identified as potentially crucial for the success or failure of oak regeneration were either included in a field inventory procedure or extracted from forest inventory databases. We found that the collected data were suitable to be analyzed in a three-step success model, which was aimed at identifying the crucial success factors for high-quality oak forest regeneration.Objective(b): Our modeling procedure, which included a Bayesian estimation approach with spike-and-slab priors,revealed that competitive pressure from the secondary tree species was the most decisive success factor;no competition, or low competition by secondary tree species appeared to be particularly beneficial for the success of high-quality oak regeneration. Also fencing and the absence of competitive vegetation(weeds, grass, bracken)seemed to be beneficial factors for the success of oak regeneration.Conclusions: Trusting in biological automation was found to be mostly useless regarding economically viable oak forest regeneration. To efficiently organize oak regeneration planning and silvicultural decision-making within a forest enterprise, it is strongly recommended to initially evaluate the annual financial and personnel capacities for carrying out young growth tending or pre-commercial thinning and only then to decide on the extent of regenerated oak stands. Careful and adaptive regeneration planning is also indispensable to secure the long-term ecological continuity in oak forests. Oak regeneration should therefore preferably take place within the close vicinity of old oak stands or directly in them. The retention of habitat trees is urgently advised.展开更多
There arc eight species and four varieties of oak in northeast China. This paper reports and describes the distribution and phylocoenogenesis of the Korean pine-broadleaved mixed forest and the mongolian oak formation...There arc eight species and four varieties of oak in northeast China. This paper reports and describes the distribution and phylocoenogenesis of the Korean pine-broadleaved mixed forest and the mongolian oak formation. The close relationship between the flora of Ussuli—Amur region and Japan is discussed. Analyses of heat and energy balance, and biomass of mongolian oak forests arc provided. Many measurements indicate that, in a nonclosed stand, the wood production of a stand is positively correlated with leaf area index (LAI).展开更多
The present study is about in vitro culture of cork oak, through callogenesis from nodes and internodes, withdrawn from seedlings of three months. These latter were obtained after acorns germination on peat. Nodes sho...The present study is about in vitro culture of cork oak, through callogenesis from nodes and internodes, withdrawn from seedlings of three months. These latter were obtained after acorns germination on peat. Nodes showed a high capacity for callogenesis and the best rate was obtained on a medium containing Woody Plant Medium (WPM) macronutrients, Murashige and Skoog (MS) micronutrients and vitamins, 4.5 μM of 6-Benzylaminopurine (BAP), 7 μM of 2-naphthalineacetic acid (NAA) and 30 g/L of Sucrose. Calluses are transplanted onto the same mineral solution, with or without growth regulators, and in the 3rd transplanting;small white embryos appear on the surface of calluses.展开更多
This study aims to investigate wood density at different levels of moisture, basic density and shrinkage of timber from Turkey oak (Quercus cerris L.) coppice forests growing in Central Italy. We also studied the va...This study aims to investigate wood density at different levels of moisture, basic density and shrinkage of timber from Turkey oak (Quercus cerris L.) coppice forests growing in Central Italy. We also studied the variability in density in the trees within and among sites. Density shows no significant statistical differences in the tested population. A higher variability in the shrinkage than in the density was found. Wood moisture is referred to as dry mass and fresh mass, which is related to many performance characteristics of wood, i.e., energy production. Trends in moisture and water content were studied because these physical parameters play an important role in the specific area of firewood which requires an accurate estimation of mass, volume and energy content. This work is a contribution to improve xylo-energy estimates of small and medium forestry issues.展开更多
To define the preliminary embryogenesis culture conditions of Moroccan Cork Oak (Quercus suber L.) in secondary propagation systems, secondary embryos formation from primary embryos were analyzed using seven macronutr...To define the preliminary embryogenesis culture conditions of Moroccan Cork Oak (Quercus suber L.) in secondary propagation systems, secondary embryos formation from primary embryos were analyzed using seven macronutrient medias: (Chalupa) (BTM), Murashige and Skoog (MS), Schenk and Hildebrant (SH), Schenk and Hildebrant with half content macronutrients (SH ?), full Gamborg (G), Margara (N30K) and Woody Plant Media(WPM). Mature primary embryos at cotyledonal stage of 8 - 10 mm, were placed in each culture medium, and supplemented with 30 g/l of glucose and 7 g/l of agar without PGR. The experimental design consisted of a Petri dish containing three embryos explants. Each one of the seven treatments was composed of ten Petri dishes. Mean number of secondary somatic embryos, clusters and new embryogenic formation on clusters were recorded after 8 weeks, and evaluated by statistical analysis. There were no significant differences (p ≤ 0.05) in clusters and new embryos on clusters formation among evaluated media;but mean number of secondary embryos was significantly higher in N30K (4.37 ± 0.48) compared with control media (1.37 ± 0.15). The morphology of secondary embryos grown in the N30K medium exclusively showed the presence of three embryogenic stages: early cotyledonal with translucide aspect, white opaque, or green, and mature embryos. These results indicate that the medium do influence the morphogenic characteristics of produced embryos. Our finding revealed that secondary somatic embryos produced in N30K medium presented better morphogenic potential, with different stages of embryogenic formation.展开更多
Populations of oak cork (Quercus suber L.) originated from different areas in Tunisia were analysed based on morphological characters to assess the overall degree of phenotypic variability, to detect similarities betw...Populations of oak cork (Quercus suber L.) originated from different areas in Tunisia were analysed based on morphological characters to assess the overall degree of phenotypic variability, to detect similarities between the genotypes and to evaluate significant forest features. One-way ANOVA analysis shows a significant difference between oak cork populations and demonstrates that parameters measured on leaves show an important degree of variability and permit to discriminate oak cork individuals. Vegetative variables are leaf length, leaf width, petioles length, number of leaf veins, petioles width, spines number, leaf area, length nipples, diameter nipples, weight nipples, and height trees. Diameter trees were scored and subjected to multivariate analysis. Results showed a considerable diversity among local germoplasme of oak cork. Principal component analysis (PCA) revealed that the characters related to the length and width of the sheets and the nipples accounted for a large proportion of the observed variability. Cluster analysis showed a typically continuous phenotypic diversity among oak cork accessions, and little asso-ciations between accessions from same geographic origin. Also, some heterogeneity within accessions that received the same denomination was evidenced. The variability observed between different populations is attached to phenotypic characters which depend primarily on two factors, gene and environment.展开更多
Lectins are carbohydrate-binding proteins with agglutination properties. There is a continuous interest in lectins due to their biological properties that can be exploited for medicinal and therapeutic purposes. The o...Lectins are carbohydrate-binding proteins with agglutination properties. There is a continuous interest in lectins due to their biological properties that can be exploited for medicinal and therapeutic purposes. The objective of this study was to isolate and characterize lectin activity in Texas Live Oak (Quercus fusiformis). More specifically, the study aimed to determine the lectin’s blood group specificity and pH stability, determine effects of seasonal variation, soil moisture and soil pH on lectin activity. The study also aimed to determine the presence of antifungal activity in Q. fusiformis extracts. Lectin activity was detected and compared via agglutination and protein assays. Protein partial purification was accomplished using diethylaminoethyl ion-exchange chromatography matrix. High Performance Liquid Chromatography (HPLC) was used to assess purity of the lectin. Results showed that Q. fusiformis extracts’ lectin activities are stable at a pH range of 5.2 - 9.2 but with a significant decrease in activity above pH 9.2. The lectin activity was significantly higher when assayed against sheep red blood cells as compared to other blood groups tested. Quercus fusiformis extract is devoid of antifungal activity against Aspergillus niger and Rhizopus stolonifer. The effects of seasonal variation, soil moisture and soil pH do not significantly correlate with lectin activity. Results from HPLC showed presence of three peaks indicating a partial purification of the Q. fusiformis lectin.展开更多
基金The work was partially supported by research project funding from the Undergraduate Research Grant,Arkansas Tech University.
文摘Quercus arkansana(Arkansas oak)is at risk of becoming endangered,as the total known population size is represented by a few isolated populations.The potential impact of climate change on this species in the near future is high,yet knowledge of its predicted effects is limited.Our study utilized the biomod2 R package to develop habi-tat suitability ensemble models based on bioclimatic and topographic environmental variables and the known loca-tions of current distribution of Q.arkansana.We predicted suitable habitats across three climate change scenarios(SSP1-2.6,SSP2-4.5,and SSP5-8.5)for 2050,2070,and 2090.Our findings reveal that the current suitable habitat for Q.arkansana is approximately 127,881 km^(2) across seven states(Texas,Arkansas,Alabama,Louisiana,Mississippi,Georgia,and Florida);approximately 9.5%is encompassed within state and federally managed protected areas.Our models predict that all current suitable habitats will disap-pear by 2050 due to climate change,resulting in a northward shift into new regions such as Tennessee and Kentucky.The large extent of suitable habitat outside protected areas sug-gests that a species-specific action plan incorporating pro-tected areas and other areas may be crucial for its conserva-tion.Moreover,protection of Q.arkansana habitat against climate change may require locally and regionally focused conservation policies,adaptive management strategies,and educational outreach among local people.
基金Financial and logistic support for this research was provided by Five Oaks Ag Research&Education Center(DS18849)University of Arkansas Division of Agriculture(PR02276)University of Arkansas at Monticello.Funding support was provided by U.S.Department of Agriculture,National Institute of Food and Agriculture,McIntire-Stennis Capacity Grant(2729 YR21-25 and ARK02594).
文摘Elevation gradients within forested wetlands have long been recognized for their role in defining species composition through factors such as hydrology and soil characteristics.Greentree reservoirs(GTRs)are leveeimpounded tracts of bottomland hardwood forest flooded throughout the winter months to provide habitat for overwintering waterfowl.Artificial flooding of GTRs alters the forest composition due to flood frequency,depth,and duration in combination with slight changes in topography.To evaluate the effect of elevation gradients,soil properties,and management techniques in the overstory species composition and red oak(Quercus spp.)species abundance,we inventoried 662 plots across 12 independent GTRs in eastern Arkansas.In the lower elevations ranging from 50.98 to 54.99 m above sea level,the importance value index(IVI)was highest for nuttall oak(Quercus texana)and overcup oak(Quercus lyrata),whereas IVI shifted to cherrybark oak(Quercus pagoda)in the higher elevations ranging from 54.99 to 58.00 m.Alpha diversity did not differ by elevation gradient,soil property,or management technique within GTRs.Beta diversity,using non-metric multi-dimensional scaling(NMDS)analysis,indicated site-specific variability significantly correlated with the environmental predictors,including elevation(R^(2)=0.57),easting(R^(2)=0.47),soil texture(R^(2)=0.21),and pH(R^(2)=0.12).Red oak species-specific mixed-effects modeling of abundance response using Poisson distribution suggested an inverse correlation of nuttall oak and a direct correlation of cherrybark oak abundance with elevation.However,willow oak(Quercus phellos)abundance was not significantly affected by elevation but was by silt loam soil texture and restoration management techniques.These findings will aid management efforts to reduce the dominance of less desirable species that are prominent under specific environmental conditions and promote the dominance of more desirable species.Ultimately GTR sustainability is increasingly important amid the unpredictable impacts of climate change on the preferred red oak species that are economically,ecologically,and environmentally valuable to the sustaining economy of the local community and managing habitats for wildlife.
基金the financial support received from The Key Project of R&D Program of Ningxia Hui Autonomous Region,China(2022BBF01003)China Agriculture Research System of MOF and MARA(CARS-29).
文摘Aging in oak barrels is widely used in enology which could bring flavor changes and aromatic complexity to wines.In the present study,the aroma compounds were analyzed from the‘Merlot’dry red wines,which were fermented in two types of fermenters(stainless steel tank and rotated oak barrel)and aged in six types of oak barrels(three geographic origins×two toasting degrees)for different time(0,3,6 and 9 months,respectively).Results showed that 30 volatiles were associated with barrels and increased during oak aging.The fermenters could influence the intensities of the toast,leathery,smoky,fruity,floral and caramel aromas.The concentration of whisky lactone,eugenol,cis-isoeugenol,and the intensities of the toast and spicy aromas were highest in the wines aged in American oak and were lowest in the wines aged in French oak barrels.The concentrations of guaiacol,syringol,trans-isoeugenol,furfural alcohol,vanilla,cis-whisky lactone enabled the medium toasting barrels to be distinguished from the light toasting ones.The compounds originating from the barrels could be used to distinguish the types of different barrels,but the other general grape-derived and fermentation-derived volatiles could not.The fermenters,oak species and toasting degrees of the barrels all had significant effects on the aroma profiles of the aged‘Merlot’dry red wines,but the influence of the geographic origin was not obvious.
文摘Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, where we sampled soils in areas that were classified by fire severity: low (LS), high (HS) and medium severity (MS), and unburned (UB), which served as the control. In each severity class, 25 transect points were randomly selected for measurement. Around each transect plot center, 3 soil samples were selected randomly and soils collected from the 0 to 20 cm depth were combined into a composite sample that was used in laboratory analysis to represent conditions at that point. Plots in the UB and LS fire classes had similar soil conditions and had higher values of factors such as saturated moisture, organic carbon, carbon dioxide, and silt and clay content. In contrast, plots in the HS and MS fire severity classes were clustered in the positive direction along the first axis that represented gradients in soil acidity, electrical conductivity, cation exchange capacity, accessible phosphorus, accessible potassium, bulk density, and sand. Soil attributes were similar in areas of HS and MS fire severity classes, whereas soil conditions in the LS class and UB controls were most similar. Fire in the LS areas either did not significantly alter the physicalchemical soil properties and microbial basal respiration, or soils were able to recover quickly after being burned.
基金supported by the laboratory of silvopastoral resources (Silvopastoral Institute-Tabarka)
文摘The need for reforestation in cork oak (Quercus suber L.) areas is challenged by difficulties. Principal among these is herbivory of young plants, vegetative competition, and slow growth rates of cork oak seedlings. We evaluated the early development of cork oak seedlings treated using tree shelters and mulching in northwestern Tunisia. We tested three tree shelter treatments (non-vented, vented, and control) to shield seedlings from animal damage and five mulch types to control competing vegetation (Italian Stone Pine, Lentisk, combination of Italian Stone Pine and Lentisk (organic mulches), gravel (inorganic mulch) and no mulch). At the end of the two-year experiment, sheltered seedlings were 89-99% taller than unshelteredseedlings and had higher numbers and lengths of shoot growth flushes. In contrast, both stem diameter growth and dry weight biomass (from samples extracted after two years) were significantly reduced inside tree shelters. Root-to-shoot ratio was not significantly different in sheltered vs. unsheltered seedlings, suggesting that tree shelters do not adversely affect this parameter. Mulching alone did not favour growth, but could be beneficial when combined with tree shelters. The combination of vented tree shelters and gravel mulch was the most effective treatment for promoting diameter, height and stem volume growth.
基金supported by the laboratory of silvopastoral resources(Silvopastoral Institute-Tabarka)
文摘We assessed the effect of mulching and tree shelters on the establishment and early growth of zeen oak(Quercus canariensis Willd.) during the first 4 years after planting in Northwestern Tunisia. Five mulch types(Italian Stone Pine(Pinus pinea L.), Lentisk(Pistacia lentiscus L.),and a combination of Italian Stone Pine and Lentisk(organic mulches), gravel(inorganic mulch) and control), and three tree shelter types(non-vented and vented tree shelters, and control) were tested. An increase in the number of internodes occurred under the gravel mulch, while a reduction in survival was found for the lentisk mulch. Tree shelters had no effect on survival, but increased mean height growth and reduced mean diameter growth during the 4 years(excepting a non-significant effect for vented tree shelter at year four). Comparison of the annual shoots and growth units(GU) between sheltered and unsheltered plants according to year of formation revealed two growth phases. In first phase, shoots were totally or partially inside the shelters; mean length of annual shoots and GU were greater for sheltered plants. The second phase was characterized by shoots emerging from shelters; mean length of annual shoots and GU were similar for all plants, with or without tree shelters. Results suggest that the use of tree shelters, particularly vented shelters, could contribute to the improvement of the artificial regeneration of zeen oak.The use of mulching alone or in combination with tree shelters did not improve zeen oak performance in the field.
基金funded by United States Department of Agriculture Forest Service Northern Research Station agreement 15-CS-11242302-122(to S.N.M.)the Ohio Agricultural Research and Development Center SEEDS Project OHOA1572(to D.M.H.)The Ohio Agricultural Research and Development Center and The Ohio State University provided fellowship funding to D.C.R。
文摘Background:Mature oak(Quercus spp.)and hickory(Carya spp.)trees are gradually being replaced by more shadetolerant tree species across the eastern U.S.,likely due to fire suppression and increased precipitation.Oaks and hickories are highly valuable to wildlife;therefore,studying their mortality patterns can provide information on the longevity of habitat quality for many animal species.Oak mortality has most often been studied following large oak decline events,but background mortality rates in forests with aging oak and hickory canopies warrant equal attention,especially in the context of widespread oak and hickory regeneration failure.Methods:We studied background mortality rates of five oak and one hickory species over a 23–25 year time period(1993–1995 to 2018),using 821/20th hectare permanent plots on the Marietta Unit of the Wayne National Forest in southeastern Ohio.We calculated mortality rates based on remeasurement of individual trees for white oak(Quercus alba),chestnut oak(Quercus montana),northern red oak(Quercus rubra),black oak(Quercus velutina),scarlet oak(Quercus coccinea),and pignut hickory(Carya glabra).For each of these species other than scarlet oak,we also modeled the relationships of mortality probability with a priori topographic,soil,stand structural,and individual tree covariates,using a mixed-effects logistic regression framework.Results:The species with the highest mortality rate was scarlet oak(61.3%),followed by northern red oak(41.4%),black oak(26.7%),pignut hickory(23.9%),white oak(23.4%),and chestnut oak(19.1%).In our models,northern red oak mortality was associated with more mesic slope positions,shallower solums,more acidic soils,and older stand ages.Pignut hickory and chestnut oak mortality rates were associated with higher basal areas on the plot,while white oak mortality showed the opposite pattern.Conclusions:Our data suggest that red oak subgenus trees in mature forests of our area will become increasingly uncommon relative to white oak subgenus trees,as the result of higher mortality rates likely related to the shorter lifespans of these species.Particularly vulnerable areas may include more mesic topographic positions,shallower or more acidic soil,and older stands.Since maintaining oak subgenus diversity is beneficial to wildlife diversity in the eastern U.S.,managers in areas with extensive mature mixed-oak forests could choose to favor the red oak subgenus when conducting silvicultural treatments.
基金supported by the National Natural Science Foundation of China (Grant No. 30872000) and the K. C. Wong Education Foundation, Hong Kong.
文摘The relationships between plant organs and root hydrological traits are not well known and the question arises whether elevated CO2 changes these relationships. This study attempted to answer this question. A pseudo-replicated experiment was conducted with two times 24 American elm (Ulmus americana L.) and 23 and 24 red oak (Quercus rubra L.) seedlings growing in ambient CO2 (around 360 μmol.L^-1) and 540 ± 7.95 μmol.L^-1 CO2 in a greenhouse. After 71 days of treatment for American elm and 77 days for red oak, 14 American elm and 12 red oak seedlings from each of the two CO2 levels were randomly selected in order to examine the flow rate of root xylem sap, root hydraulic conductance, total root hydraulic conductivity, fine root and coarse root hydraulic conductivity. All seedlings were harvested to investigate total plant biomass, stem biomass and leaf biomass, leaf area, height, basal diameter, total root biomass, coarse root biomass and fine root biomass. The following conclusions are reached: 1) plant organs respond to the elevated CO2 level earlier than hydraulic traits of roots and may gradually lead to changes in hydraulic traits; 2) plant organs have different relationships with hydraulic traits of roots and elevated CO2 changes these relationships; the changes may be of importance for plants as means to acclimatize to changing environments; 3) biomass of coarse roots increased rather more than that of fine roots; 4) Lorentzian and Caussian models are better in estimating the biomass of seedlings than single-variable models. Key words American elm, biomass, elevated CO2, modeling, red oak, root hydraulic traits
基金funded by the Fundamental Research Funds for the Central Non-profit Research Institution of CAF(CAFYBB2018ZB001)。
文摘Background:The relationship between physiological age of parental trees and lifespan of clonal offspring is unclear.White oak(Quercus fabri Hance)has a high sprouting capability after harvest,with the regenerated sprouts being typical clonal individuals.To determine whether regenerated sprouts undergo rapid senescence compared with the parent,the senescence levels of 5-,10-,20-and 40-year-old regenerated stump sprouts in a natural forest were evaluated.The antioxidative abilities and transcriptomes in these leaves and shoots were compared.Results:Older regenerated sprouts still had robust antioxidative systems,with 40-year-old sprouts having lower peroxidation product levels but similar antioxidative enzyme activity levels compared with 5-year-old sprouts.Older leaves had greater transcriptional activities in pathways related to cell growth and division than younger leaves.However,older sprouts had some unhealthy characteristics,such as increased base excision repair levels and upregulated phagosome,proteasome and glycerophospholipid metabolism pathways in 40-year-old leaves,which indicates that DNA damage and tissue remodeling occurred more frequently than in younger leaves.Additionally,plant-pathogen interactions and MAPK signals pathways were upregulated in older shoots,which indicates that older shoots suffered from more pathogen-related biotic stress.Conclusions:The 40-year-old sprouts still had the same vitality level as the 5-year-old sprouts,although the former had some unhealthy characteristics.We conclude that during their first 40 years of growth,regenerated stump sprouts do not begin to senesce,and that physiological age of parental trees does not significantly affect the lifespan of its clonal offspring.
基金partly supported by the long-term research programme Sustainable Forestry and Global Changes implemented by the Lithuanian Research Centre for Agriculture and Forestry
文摘This study was conducted to determine the parent-off spring genetic structure of the pedunculate oak(Quercus robur L.),sessile oak(Q.petraea[Matt.]Liebl.)and their hybrids.Forty half-sib Quercus families and their maternal trees originating from one tree stand in southern Lithuania were analyzed using SSR and RAPD markers.Based on a preliminary study of leaf morphological traits,the individuals separated into six groups.The studied halfsib oak families were also compared for allelic diversity,including group variations;genotypic structure;genetic diversity;and the degree of genetic subdivision and diff erentiation.The level of genetic variation and subdivision was lower in the hybrid families than in the families of the parental species.Genotypic analysis of the half-sibling off spring showed the asymmetric nature of interspecifi c hybridization processes of pedunculate and sessile oaks in mixed stands.
文摘In the present study, we tested the effect of amino acids on secondary somatic embryogenesis of Moroccan cork oak (Quercus suber L.). Secondary mature and immature somatic embryos were obtained from primary somatic embryos cultured in N30K medium supplemented with nineteen amino acids. Stimulation of embryogenesis was dependent on the type and concentration of amino acid in the medium. Thus, L-glutamine and L-asparagine at 3.42 mM have been proved to be the most favorable for the formation of functional somatic embryos and the induction of secondary somatic embryos.
文摘The canopy net photosynthesis rate of Mongolian oak (Quercus mongolica) tree species that are dominant in East Asia and Korea is estimated with empirical models derived from field experimental data obtained from the Nam-San site in Seoul, Korea for the growing period from early May to late October in 2010. The empirical models include the attenuation function of photosynthetic photon flux density (PPFD) (r2 = 0.98-0.99, p r2 = 0.99, p < 0.001) derived from the measured data at several levels within the canopy. The incident PPFD at each level within canopy significantly varies diurnally and seasonally due to the seasonal variation of the total plant area index (TPAI = leaf area index + wood silhouette area index) and the light shielding effect of light path-length through the canopy in association with the variation of solar elevation angle. Consequently, a remarkable seasonal variation of the total canopy net photosynthesis rate of Q. mongolica forest stand is found for its growing period. The PPFD exceeding 1000 μmol m-2·s-1 is found to cause the decrease of net photosynthesis rate due to the thermal stress in the early (May) and late (September) growing period. During the whole growing season, the estimated total canopy net photosynthesis rate is found to be about 3.3 kg CO2 m-2.
基金the funding of the project “Quer Con–Longterm conservation of ecological continuity in oak forests”(Grant number32694)by the German Federal Environmental Foundation(DBU)
文摘Background: Within the framework of close-to-nature forestry, oak forest(Quercus robur, Q. petraea) regeneration techniques that consider both silvicultural and nature conservation demands have become a very important issue.While there are many experimental and local studies that aim at disentangling the relationships between different environmental and silvicultural factors and the success of oak regeneration, systematic supra-regional studies at the greater landscape level are missing so far.Against this background, the first objective(a) of this study was to present an efficient and sufficiently accurate sampling scheme for supra-regional forest regrowth inventories, which we applied to young oaks stands. The second, and major, objective(b) was to identify the crucial success factors for high-quality oak forest regeneration in northwest Germany.Results: Objective(a): Factors that have been identified as potentially crucial for the success or failure of oak regeneration were either included in a field inventory procedure or extracted from forest inventory databases. We found that the collected data were suitable to be analyzed in a three-step success model, which was aimed at identifying the crucial success factors for high-quality oak forest regeneration.Objective(b): Our modeling procedure, which included a Bayesian estimation approach with spike-and-slab priors,revealed that competitive pressure from the secondary tree species was the most decisive success factor;no competition, or low competition by secondary tree species appeared to be particularly beneficial for the success of high-quality oak regeneration. Also fencing and the absence of competitive vegetation(weeds, grass, bracken)seemed to be beneficial factors for the success of oak regeneration.Conclusions: Trusting in biological automation was found to be mostly useless regarding economically viable oak forest regeneration. To efficiently organize oak regeneration planning and silvicultural decision-making within a forest enterprise, it is strongly recommended to initially evaluate the annual financial and personnel capacities for carrying out young growth tending or pre-commercial thinning and only then to decide on the extent of regenerated oak stands. Careful and adaptive regeneration planning is also indispensable to secure the long-term ecological continuity in oak forests. Oak regeneration should therefore preferably take place within the close vicinity of old oak stands or directly in them. The retention of habitat trees is urgently advised.
文摘There arc eight species and four varieties of oak in northeast China. This paper reports and describes the distribution and phylocoenogenesis of the Korean pine-broadleaved mixed forest and the mongolian oak formation. The close relationship between the flora of Ussuli—Amur region and Japan is discussed. Analyses of heat and energy balance, and biomass of mongolian oak forests arc provided. Many measurements indicate that, in a nonclosed stand, the wood production of a stand is positively correlated with leaf area index (LAI).
文摘The present study is about in vitro culture of cork oak, through callogenesis from nodes and internodes, withdrawn from seedlings of three months. These latter were obtained after acorns germination on peat. Nodes showed a high capacity for callogenesis and the best rate was obtained on a medium containing Woody Plant Medium (WPM) macronutrients, Murashige and Skoog (MS) micronutrients and vitamins, 4.5 μM of 6-Benzylaminopurine (BAP), 7 μM of 2-naphthalineacetic acid (NAA) and 30 g/L of Sucrose. Calluses are transplanted onto the same mineral solution, with or without growth regulators, and in the 3rd transplanting;small white embryos appear on the surface of calluses.
文摘This study aims to investigate wood density at different levels of moisture, basic density and shrinkage of timber from Turkey oak (Quercus cerris L.) coppice forests growing in Central Italy. We also studied the variability in density in the trees within and among sites. Density shows no significant statistical differences in the tested population. A higher variability in the shrinkage than in the density was found. Wood moisture is referred to as dry mass and fresh mass, which is related to many performance characteristics of wood, i.e., energy production. Trends in moisture and water content were studied because these physical parameters play an important role in the specific area of firewood which requires an accurate estimation of mass, volume and energy content. This work is a contribution to improve xylo-energy estimates of small and medium forestry issues.
文摘To define the preliminary embryogenesis culture conditions of Moroccan Cork Oak (Quercus suber L.) in secondary propagation systems, secondary embryos formation from primary embryos were analyzed using seven macronutrient medias: (Chalupa) (BTM), Murashige and Skoog (MS), Schenk and Hildebrant (SH), Schenk and Hildebrant with half content macronutrients (SH ?), full Gamborg (G), Margara (N30K) and Woody Plant Media(WPM). Mature primary embryos at cotyledonal stage of 8 - 10 mm, were placed in each culture medium, and supplemented with 30 g/l of glucose and 7 g/l of agar without PGR. The experimental design consisted of a Petri dish containing three embryos explants. Each one of the seven treatments was composed of ten Petri dishes. Mean number of secondary somatic embryos, clusters and new embryogenic formation on clusters were recorded after 8 weeks, and evaluated by statistical analysis. There were no significant differences (p ≤ 0.05) in clusters and new embryos on clusters formation among evaluated media;but mean number of secondary embryos was significantly higher in N30K (4.37 ± 0.48) compared with control media (1.37 ± 0.15). The morphology of secondary embryos grown in the N30K medium exclusively showed the presence of three embryogenic stages: early cotyledonal with translucide aspect, white opaque, or green, and mature embryos. These results indicate that the medium do influence the morphogenic characteristics of produced embryos. Our finding revealed that secondary somatic embryos produced in N30K medium presented better morphogenic potential, with different stages of embryogenic formation.
文摘Populations of oak cork (Quercus suber L.) originated from different areas in Tunisia were analysed based on morphological characters to assess the overall degree of phenotypic variability, to detect similarities between the genotypes and to evaluate significant forest features. One-way ANOVA analysis shows a significant difference between oak cork populations and demonstrates that parameters measured on leaves show an important degree of variability and permit to discriminate oak cork individuals. Vegetative variables are leaf length, leaf width, petioles length, number of leaf veins, petioles width, spines number, leaf area, length nipples, diameter nipples, weight nipples, and height trees. Diameter trees were scored and subjected to multivariate analysis. Results showed a considerable diversity among local germoplasme of oak cork. Principal component analysis (PCA) revealed that the characters related to the length and width of the sheets and the nipples accounted for a large proportion of the observed variability. Cluster analysis showed a typically continuous phenotypic diversity among oak cork accessions, and little asso-ciations between accessions from same geographic origin. Also, some heterogeneity within accessions that received the same denomination was evidenced. The variability observed between different populations is attached to phenotypic characters which depend primarily on two factors, gene and environment.
文摘Lectins are carbohydrate-binding proteins with agglutination properties. There is a continuous interest in lectins due to their biological properties that can be exploited for medicinal and therapeutic purposes. The objective of this study was to isolate and characterize lectin activity in Texas Live Oak (Quercus fusiformis). More specifically, the study aimed to determine the lectin’s blood group specificity and pH stability, determine effects of seasonal variation, soil moisture and soil pH on lectin activity. The study also aimed to determine the presence of antifungal activity in Q. fusiformis extracts. Lectin activity was detected and compared via agglutination and protein assays. Protein partial purification was accomplished using diethylaminoethyl ion-exchange chromatography matrix. High Performance Liquid Chromatography (HPLC) was used to assess purity of the lectin. Results showed that Q. fusiformis extracts’ lectin activities are stable at a pH range of 5.2 - 9.2 but with a significant decrease in activity above pH 9.2. The lectin activity was significantly higher when assayed against sheep red blood cells as compared to other blood groups tested. Quercus fusiformis extract is devoid of antifungal activity against Aspergillus niger and Rhizopus stolonifer. The effects of seasonal variation, soil moisture and soil pH do not significantly correlate with lectin activity. Results from HPLC showed presence of three peaks indicating a partial purification of the Q. fusiformis lectin.