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Sample records for aspen populus tremula

  1. Genetic variation in functional traits influences arthropod community composition in aspen (Populus tremula L.).

    Science.gov (United States)

    Robinson, Kathryn M; Ingvarsson, Pär K; Jansson, Stefan; Albrectsen, Benedicte R

    2012-01-01

    We conducted a study of natural variation in functional leaf traits and herbivory in 116 clones of European aspen, Populus tremula L., the Swedish Aspen (SwAsp) collection, originating from ten degrees of latitude across Sweden and grown in a common garden. In surveys of phytophagous arthropods over two years, we found the aspen canopy supports nearly 100 morphospecies. We identified significant broad-sense heritability of plant functional traits, basic plant defence chemistry, and arthropod community traits. The majority of arthropods were specialists, those coevolved with P. tremula to tolerate and even utilize leaf defence compounds. Arthropod abundance and richness were more closely related to plant growth rates than general chemical defences and relationships were identified between the arthropod community and stem growth, leaf and petiole morphology, anthocyanins, and condensed tannins. Heritable genetic variation in plant traits in young aspen was found to structure arthropod community; however no single trait drives the preferences of arthropod folivores among young aspen genotypes. The influence of natural variation in plant traits on the arthropod community indicates the importance of maintaining genetic variation in wild trees as keystone species for biodiversity. It further suggests that aspen can be a resource for the study of mechanisms of natural resistance to herbivores.

  2. Genetic variation in functional traits influences arthropod community composition in aspen (Populus tremula L..

    Directory of Open Access Journals (Sweden)

    Kathryn M Robinson

    Full Text Available We conducted a study of natural variation in functional leaf traits and herbivory in 116 clones of European aspen, Populus tremula L., the Swedish Aspen (SwAsp collection, originating from ten degrees of latitude across Sweden and grown in a common garden. In surveys of phytophagous arthropods over two years, we found the aspen canopy supports nearly 100 morphospecies. We identified significant broad-sense heritability of plant functional traits, basic plant defence chemistry, and arthropod community traits. The majority of arthropods were specialists, those coevolved with P. tremula to tolerate and even utilize leaf defence compounds. Arthropod abundance and richness were more closely related to plant growth rates than general chemical defences and relationships were identified between the arthropod community and stem growth, leaf and petiole morphology, anthocyanins, and condensed tannins. Heritable genetic variation in plant traits in young aspen was found to structure arthropod community; however no single trait drives the preferences of arthropod folivores among young aspen genotypes. The influence of natural variation in plant traits on the arthropod community indicates the importance of maintaining genetic variation in wild trees as keystone species for biodiversity. It further suggests that aspen can be a resource for the study of mechanisms of natural resistance to herbivores.

  3. Allergic contact dermatitis from salicyl alcohol and salicylaldehyde in aspen bark (Populus tremula).

    Science.gov (United States)

    Aalto-Korte, Kristiina; Välimaa, Jarmo; Henriks-Eckerman, Maj-Len; Jolanki, Riitta

    2005-02-01

    Salicyl alcohol or 2-methylolphenol is a well-known allergen in phenol-formaldehyde resins and a strong sensitizer in guinea pigs. There is 1 previous report of allergic contact dermatitis from salicyl alcohol in aspen bark. We describe a second case with concomitant allergy to salicylaldehyde. An elk researcher who had handled leaves from various trees presented with eczema of the hands, face, flexures, trunk and extremities. Patch testing showed sensitivity to salicyl alcohol, salicylaldehyde, balsam of Peru (Myroxylon pereirae resin), aspen wood dust and an extract prepared from the bark of aspen (Populus tremula). Weaker reactions were observed to bark extracts of rowan (Sorbus aucuparia), tea-leaved willow (Salix phylicifolia) and goat willow (Salix caprea). We analysed salicyl alcohol and salicylaldehyde in the bark extracts and found the 2 chemicals in equal amounts, about 0.9 microg/mg in aspen bark and in lower concentrations in rowan and the willows. We did not find either of the chemicals in the test substance of balsam of Peru (Myroxylon pereirae). Besides salicyl alcohol, salicylaldehyde is also recommended to be used to screen for contact allergy to aspen. Both of these chemicals should be tested in forest workers in areas where aspen is growing.

  4. Transcriptome responses to aluminum stress in roots of aspen (Populus tremula

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    Grisel Nadine

    2010-08-01

    Full Text Available Abstract Background Ionic aluminum (mainly Al3+ is rhizotoxic and can be present in acid soils at concentrations high enough to inhibit root growth. Many forest tree species grow naturally in acid soils and often tolerate high concentrations of Al. Previously, we have shown that aspen (Populus tremula releases citrate and oxalate from roots in response to Al exposure. To obtain further insights into the root responses of aspen to Al, we investigated root gene expression at Al conditions that inhibit root growth. Results Treatment of the aspen roots with 500 μM Al induced a strong inhibition of root growth within 6 h of exposure time. The root growth subsequently recovered, reaching growth rates comparable to that of control plants. Changes in gene expression were determined after 6 h, 2 d, and 10 d of Al exposure. Replicated transcriptome analyses using the Affymetrix poplar genome array revealed a total of 175 significantly up-regulated and 69 down-regulated genes, of which 70% could be annotated based on Arabidopsis genome resources. Between 6 h and 2 d, the number of responsive genes strongly decreased from 202 to 26, and then the number of changes remained low. The responses after 6 h were characterized by genes involved in cell wall modification, ion transport, and oxidative stress. Two genes with prolonged induction were closely related to the Arabidopsis Al tolerance genes ALS3 (for Al sensitive 3 and MATE (for multidrug and toxin efflux protein, mediating citrate efflux. Patterns of expression in different plant organs and in response to Al indicated that the two aspen genes are homologs of the Arabidopsis ALS3 and MATE. Conclusion Exposure of aspen roots to Al results in a rapid inhibition of root growth and a large change in root gene expression. The subsequent root growth recovery and the concomitant reduction in the number of responsive genes presumably reflect the success of the roots in activating Al tolerance mechanisms. The

  5. Conservation and yield aspects of old European aspen Populus tremula L. in Swedish forestry

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    Hazell, Per [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Management and Products

    1999-06-01

    Biodiversity issues are becoming integrated parts of Swedish forest management. In this context, the amount and distribution of broadleaved species, including aspen, are important. This thesis summarises results of two studies in which species from the rich epiphytic flora on aspen were used to evaluate important features of aspens, and two studies relating these features to production losses due to retention of aspen. The presence and abundance of four epiphytic, bark-living bryophytes in relation to stand and host-tree characteristics, were investigated in four mixed forest stands in central Sweden. There was no general and consistent relation between aspen density and bryophyte presence. Large diameter and rough bark of the aspen host, together with site factors and stand density around the host, were important. On 35 clearfelled areas, the bryophyte Antitrichia curtipendula (Hedw.) Brid. and the lichen Lobaria pulmonaria (L.) Hoffm., species considered sensitive to clearfelling, were transplanted on retained aspen stems. As a reference, transplants were made on aspens in adjacent old stands. After two years the bryophyte showed its highest vitality in the forest, but was also vigorous on the north side of retained trees. The lichen thrived best on the clearfelled areas, on the north side of trees retained in groups. For conservation purposes, aspen are best retained in groups. Qualitative and quantitative aspects of retained large aspens (diameter 49.6{+-}7.0 cm and height 29.4{+-}1.0 m) were studied in a 110-year-old aspen stand. Twelve trees were destructively analysed to establish allometric equations relating stem, bark and branch biomass and current annual stem increment (CAI{sub s}) to diameter at breast height. Biomass of the mean tree was 1172 kg, of which 80% was stemwood. CAI{sub s} was 1.5% of total stem biomass. Finally, the yield of a 44-year-old Norway spruce stand under an aspen overstorey was compared with that of pure Norway spruce, estimated

  6. Intraspecific variation in root and leaf traits and leaf-root trait linkages in eight aspen demes (Populus tremula and P. tremuloides).

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    Hajek, Peter; Hertel, Dietrich; Leuschner, Christoph

    2013-01-01

    Leaf and fine root morphology and physiology have been found to vary considerably among tree species, but not much is known about intraspecific variation in root traits and their relatedness to leaf traits. Various aspen progenies (Populus tremula and P. tremuloides) with different growth performance are used in short-rotation forestry. Hence, a better understanding of the link between root trait syndromes and the adaptation of a deme to a particular environment is essential in order to improve the match between planted varieties and their growth conditions. We examined the between-deme (genetic) and within-deme (mostly environmental) variation in important fine root traits [mean root diameter, specific root area (SRA) and specific root length (SRL), root tissue density (RTD), root tip abundance, root N concentration] and their co-variation with leaf traits [specific leaf area (SLA), leaf size, leaf N concentration] in eight genetically distinct P. tremula and P. tremuloides demes. Five of the six root traits varied significantly between the demes with largest genotypic variation in root tip abundance and lowest in mean root diameter and RTD (no significant difference). Within-deme variation in root morphology was as large as between-deme variation suggesting a relatively low genetic control. Significant relationships existed neither between SLA and SRA nor between leaf N and root N concentration in a plant. Contrary to expectation, high aboveground relative growth rates (RGR) were associated with large, and not small, fine root diameters with low SRA and SRL. Compared to leaf traits, the influence of root traits on RGR was generally low. We conclude that aspen exhibits large intraspecific variation in leaf and also in root morphological traits which is only partly explained by genetic distances. A root order-related analysis might give deeper insights into intraspecific root trait variation.

  7. Above-ground biomass characteristics of young hybrid aspen (Populus tremula L. x P. tremuloides Michx.) plantations on former agricultural land in Estonia

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    Tullus, Arvo; Tullus, Hardi; Soo, Tea; Paern, Linnar [Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, 51014 Tartu (Estonia)

    2009-11-15

    Fifty biomass production model trees were analysed in 7-yr-old commercial hybrid aspen plantations established on abandoned agricultural land in Estonia. Above-ground leafless biomass (ALB) of the model trees varied from 0.1 to 9.8 kg DM. The ALB of plantations with a density of 880-1340 trees ha{sup -1} growing on former field soils was between 2.18 and 8.54 t DM ha{sup -1}. The amount of nitrogen accumulated in the ALB varied between 14.4 and 48.5 kg ha{sup -1}, the amount of phosphorus, between 1.7 and 5.9 kg ha{sup -1}, and the amount of potassium, between 6.5 and 21.9 kg ha{sup -1}. The removal of major mineral nutrients from the site with the removal of woody biomass in 7-yr-old plantations would be relatively small, constituting 0.5-3.4% of the nutrient pool in the humus layer of the previously fertilized field soils. The stembark content decreases rapidly until the DBH reaches 4 cm, which can be considered a target diameter for the hybrid aspen coppicing system. (author)

  8. Comparison of VOC emissions between air-dried and heat-treated Norway spruce ( Picea abies), Scots pine ( Pinus sylvesteris) and European aspen ( Populus tremula) wood

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    Hyttinen, Marko; Masalin-Weijo, Marika; Kalliokoski, Pentti; Pasanen, Pertti

    2010-12-01

    Heat-treated wood is an increasingly popular decoration material. Heat-treatment improves dimensional stability of the wood and also prevents rot fungus growth. Although production of heat-treated wood has been rapidly increasing, there is only little information about the VOC emissions of heat-treated wood and its possible influences on indoor air quality. In the present study, VOC emissions from three untreated (air-dried) and heat-treated wood species were compared during a four weeks test period. It appeared that different wood species had clearly different VOC emission profiles. Heat-treatment was found to decrease VOC emissions significantly and change their composition. Especially, emissions of terpenes decreased from softwood samples and aldehydes from European aspen samples. Emissions of total aldehydes and organic acids were at the same level or slightly higher from heat treated than air-dried softwood samples. In agreement with another recent study, the emissions of furfural were found to increase and those of hexanal to decrease from all the wood species investigated. In contrast to air-dried wood samples, emissions of VOCs were almost in steady state from heat treated wood samples even in the beginning of the test.

  9. Genotypic variation in a foundation tree (Populus tremula L.) explains community structure of associated epiphytes.

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    Davies, Chantel; Ellis, Christopher J; Iason, Glenn R; Ennos, Richard A

    2014-01-01

    Community genetics hypothesizes that within a foundation species, the genotype of an individual significantly influences the assemblage of dependent organisms. To assess whether these intra-specific genetic effects are ecologically important, it is required to compare their impact on dependent organisms with that attributable to environmental variation experienced over relevant spatial scales. We assessed bark epiphytes on 27 aspen (Populus tremula L.) genotypes grown in a randomized experimental array at two contrasting sites spanning the environmental conditions from which the aspen genotypes were collected. We found that variation in aspen genotype significantly influenced bark epiphyte community composition, and to the same degree as environmental variation between the test sites. We conclude that maintaining genotypic diversity of foundation species may be crucial for conservation of associated biodiversity.

  10. Genome Sequences of Populus tremula Chloroplast and Mitochondrion: Implications for Holistic Poplar Breeding.

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    Birgit Kersten

    Full Text Available Complete Populus genome sequences are available for the nucleus (P. trichocarpa; section Tacamahaca and for chloroplasts (seven species, but not for mitochondria. Here, we provide the complete genome sequences of the chloroplast and the mitochondrion for the clones P. tremula W52 and P. tremula x P. alba 717-1B4 (section Populus. The organization of the chloroplast genomes of both Populus clones is described. A phylogenetic tree constructed from all available complete chloroplast DNA sequences of Populus was not congruent with the assignment of the related species to different Populus sections. In total, 3,024 variable nucleotide positions were identified among all compared Populus chloroplast DNA sequences. The 5-prime part of the LSC from trnH to atpA showed the highest frequency of variations. The variable positions included 163 positions with SNPs allowing for differentiating the two clones with P. tremula chloroplast genomes (W52, 717-1B4 from the other seven Populus individuals. These potential P. tremula-specific SNPs were displayed as a whole-plastome barcode on the P. tremula W52 chloroplast DNA sequence. Three of these SNPs and one InDel in the trnH-psbA linker were successfully validated by Sanger sequencing in an extended set of Populus individuals. The complete mitochondrial genome sequence of P. tremula is the first in the family of Salicaceae. The mitochondrial genomes of the two clones are 783,442 bp (W52 and 783,513 bp (717-1B4 in size, structurally very similar and organized as single circles. DNA sequence regions with high similarity to the W52 chloroplast sequence account for about 2% of the W52 mitochondrial genome. The mean SNP frequency was found to be nearly six fold higher in the chloroplast than in the mitochondrial genome when comparing 717-1B4 with W52. The availability of the genomic information of all three DNA-containing cell organelles will allow a holistic approach in poplar molecular breeding in the future.

  11. Rooting of hybrid clones of Populus tremula L. x P. tremuloides Michx. by stem cuttings derived from micropropagated plants

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    Qibin Yu [Univ. of Helsinki (Finland). Dept. of Plant Biology; Maentylae, N. [Univ. of Turku (Finland). Dept. of Biology, Plant Physiology and Molecular Biology; Salonen, M. [Finnish Forest Research Inst., Laeyliaeinen (Finland). Haapastensyrjae Breeding Station

    2001-07-01

    Propagation costs could be cut by replacing part of the micropropagation process with steps involving more traditional techniques. This study explored possibilities for improving existing vegetative propagation techniques for aspen using stem cuttings obtained from micropropagated plants. Vegetative propagation through stem cuttings was studied in 10 micropropagated hybrid aspen clones (Populus tremula L. x P. tremuloides Michx). Cuttings containing one axillary bud were harvested from the same donor plants twice during the growing season: the first harvest in May and the second harvest in July. Rooting percentage was correlated positively with root length, number of roots and height of cutting plant but negatively with length of rooting. The average rooting percentage was 53% in the first harvest and 27% in second harvest. Indole-3-butyric acid treatments (1.2 mM) significantly improved rooting in the second harvest, but not in the first harvest, suggesting different endogenous auxin levels in the cuttings. A significant variation for most traits related to rooting ability was found among the clones, indicating that clonal effects play an important role in the propagation of aspen. Thus, clones with a good response in shoot growth and rooting could be exploited in large-scale propagation using stem cuttings.

  12. Seasonal dynamics of the photosynthetic pigments content in Populus tremula L. leaves at the adaptation on an open-pit coal mine revegetating dump

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    Yu. V. Zagurskaya

    2017-02-01

    Full Text Available Seasonal dynamics of the basic photosynthetic pigments (a and b chlorophylls, carotenoids content in the samples of aspen Populus tremula during natural regeneration on a revegetating pit dump of a worked-out coal pit has been studied. The studies were conducted every ten days during the vegetation period in 2015 (June–September on the territory of «Yuzhniy» dump of «Kedrovskiy» open-pit coal mine (Kemerovo region. The pigment content was identified by the means of spectrophotometric detection. The content of photosynthetic pigments in aspen leaves was calculated on oven-dry weight of the leaves, as moisture aspen leaves can greatly vary, and the determination of accuracy of dry matter content higher than the for specific gravity of the sheet. No changes in visible absorption spectrum of acetone extracts indicating pheophytin formation in chlorophylls have been identified. For all variants the larger amount of b chlorophyll was contained in control samples. The largest differences in a/b chlorophylls and chlorophylls/carotenoids ratio were observed in the end of vegetation period. The ratio between a and b chlorophylls of aspen leaves in both cases by the end of the season was considerably lower. The adaptation of aspen photosynthetic system to the revegetating dump conditions was performed due to decrease in the total pigment content and the percent of b chlorophyll in their composition.

  13. Impact du stress hydrique sur le fonctionnement hydraulique foliaire du peuplier Populus tremula x alba

    OpenAIRE

    Daaboul, Philippe

    2015-01-01

    Afin d’aborder l’impact du stress hydrique sur le fonctionnement hydraulique foliaire, des plants de Populus tremula x alba ont été soumis à un stress hydrique modéré ou sévère pendant une semaine par ajout de PEG dans la solution nutritive. La mesure de paramètres écophysiologiques et moléculaires tissus spécifiques a permis de dégager plusieurs tendances sur la caractérisation de l’influence du stress. Les deux types de stress n’ont que peu d’impact sur la croissance et la capacité de synth...

  14. Widespread triploidy in Western North American aspen (Populus tremuloides).

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    Mock, Karen E; Callahan, Colin M; Islam-Faridi, M Nurul; Shaw, John D; Rai, Hardeep S; Sanderson, Stewart C; Rowe, Carol A; Ryel, Ronald J; Madritch, Michael D; Gardner, Richard S; Wolf, Paul G

    2012-01-01

    We document high rates of triploidy in aspen (Populus tremuloides) across the western USA (up to 69% of genets), and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species), climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes.

  15. Widespread triploidy in Western North American aspen (Populus tremuloides.

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    Karen E Mock

    Full Text Available We document high rates of triploidy in aspen (Populus tremuloides across the western USA (up to 69% of genets, and ask whether the incidence of triploidy across the species range corresponds with latitude, glacial history (as has been documented in other species, climate, or regional variance in clone size. Using a combination of microsatellite genotyping, flow cytometry, and cytology, we demonstrate that triploidy is highest in unglaciated, drought-prone regions of North America, where the largest clone sizes have been reported for this species. While we cannot completely rule out a low incidence of undetected aneuploidy, tetraploidy or duplicated loci, our evidence suggests that these phenomena are unlikely to be significant contributors to our observed patterns. We suggest that the distribution of triploid aspen is due to a positive synergy between triploidy and ecological factors driving clonality. Although triploids are expected to have low fertility, they are hypothesized to be an evolutionary link to sexual tetraploidy. Thus, interactions between clonality and polyploidy may be a broadly important component of geographic speciation patterns in perennial plants. Further, cytotypes are expected to show physiological and structural differences which may influence susceptibility to ecological factors such as drought, and we suggest that cytotype may be a significant and previously overlooked factor in recent patterns of high aspen mortality in the southwestern portion of the species range. Finally, triploidy should be carefully considered as a source of variance in genomic and ecological studies of aspen, particularly in western U.S. landscapes.

  16. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others

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    Bandau, Franziska; Decker, Vicki Huizu Guo; Gundale, Michael J.; Albrectsen, Benedicte Riber

    2015-01-01

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype’s baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a

  17. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others.

    Directory of Open Access Journals (Sweden)

    Franziska Bandau

    Full Text Available Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses

  18. Genotypic Tannin Levels in Populus tremula Impact the Way Nitrogen Enrichment Affects Growth and Allocation Responses for Some Traits and Not for Others.

    Science.gov (United States)

    Bandau, Franziska; Decker, Vicki Huizu Guo; Gundale, Michael J; Albrectsen, Benedicte Riber

    2015-01-01

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root:shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a

  19. Populations of aspen (Populus tremuloides Michx.) with different evolutionary histories differ in their climate occupancy.

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    Greer, Burke T; Still, Christopher; Howe, Glenn T; Tague, Christina; Roberts, Dar A

    2016-05-01

    Quaking aspens (Populus tremuloides Michx.) are found in diverse habitats throughout North America. While the biogeography of aspens' distribution has been documented, the drivers of the phenotypic diversity of aspen are still being explored. In our study, we examined differences in climate between northern and southwestern populations of aspen, finding large-scale differences between the populations. Our results suggest that northern and southwestern populations live in distinct climates and support the inclusion of genetic and phenotypic data with species distribution modeling for predicting aspens' distribution.

  20. Elevated Rocky Mountain elk numbers prevent positive effects of fire on quaking aspen (Populus tremuloides) recruitment

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    Smith, David Solance; Fettig, Stephen M.; Bowker, Matthew A.

    2016-01-01

    Quaking aspen (Populus tremuloides) is the most widespread tree species in North America and has supported a unique ecosystem for tens of thousands of years, yet is currently threatened by dramatic loss and possible local extinctions. While multiple factors such as climate change and fire suppression are thought to contribute to aspen’s decline, increased browsing by elk (Cervus elaphus), which have experienced dramatic population increases in the last ∼80 years, may severely inhibit aspen growth and regeneration. Fires are known to favor aspen recovery, but in the last several decades the spatial scale and intensity of wildfires has greatly increased, with poorly understood ramifications for aspen growth. Here, focusing on the 2000 Cerro Grande fire in central New Mexico – one of the earliest fires described as a “mega-fire” - we use three methods to examine the impact of elk browsing on aspen regeneration after a mega-fire. First, we use an exclosure experiment to show that aspen growing in the absence of elk were 3× taller than trees growing in the presence of elk. Further, aspen that were both protected from elk and experienced burning were 8.5× taller than unburned trees growing in the presence of elk, suggesting that the combination of release from herbivores and stimulation from fire creates the largest aspen growth rates. Second, using surveys at the landscape level, we found a correlation between elk browsing intensity and aspen height, such that where elk browsing was highest, aspen were shortest. This relationship between elk browsing intensity and aspen height was stronger in burned (r = −0.53) compared to unburned (r = −0.24) areas. Third, in conjunction with the landscape-level surveys, we identified possible natural refugia, microsites containing downed logs, shrubs etc. that may inhibit elk browsing by physically blocking aspen from elk or by impeding elk’s ability to move through the forest patch. We did not find any

  1. Cellulose and lignin biosynthesis is altered by ozone in wood of hybrid poplar (Populus tremula × alba).

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    Richet, Nicolas; Afif, Dany; Huber, Françoise; Pollet, Brigitte; Banvoy, Jacques; El Zein, Rana; Lapierre, Catherine; Dizengremel, Pierre; Perré, Patrick; Cabané, Mireille

    2011-06-01

    Wood formation in trees is a dynamic process that is strongly affected by environmental factors. However, the impact of ozone on wood is poorly documented. The objective of this study was to assess the effects of ozone on wood formation by focusing on the two major wood components, cellulose and lignin, and analysing any anatomical modifications. Young hybrid poplars (Populus tremula × alba) were cultivated under different ozone concentrations (50, 100, 200, and 300 l l(-1)). As upright poplars usually develop tension wood in a non-set pattern, the trees were bent in order to induce tension wood formation on the upper side of the stem and normal or opposite wood on the lower side. Biosynthesis of cellulose and lignin (enzymes and RNA levels), together with cambial growth, decreased in response to ozone exposure. The cellulose to lignin ratio was reduced, suggesting that cellulose biosynthesis was more affected than that of lignin. Tension wood was generally more altered than opposite wood, especially at the anatomical level. Tension wood may be more susceptible to reduced carbon allocation to the stems under ozone exposure. These results suggested a coordinated regulation of cellulose and lignin deposition to sustain mechanical strength under ozone. The modifications of the cellulose to lignin ratio and wood anatomy could allow the tree to maintain radial growth while minimizing carbon cost.

  2. Response of Populus x canescens (Populus tremula x alba) to high concentration of NaCl stress

    Institute of Scientific and Technical Information of China (English)

    GAO Jian; PENG Zhen-hua

    2006-01-01

    Populus x canescens was cultivated on solid substrate and treated by salt (150 mM NaCl). The growth parametersincluding new leaf formation, height increment, diameter at the base increment, fresh and dry mass of leaf, stem, coarse root, and fine root were determined. The nutrient elements in leaves of samples under salt stress and the control, and the chlorophyll fluorescence of plants separated dark and light, initial fluorescence (Fo), and maximum fluorescence (Fm) were measured. Results showed that 150 mM NaCl treatment resulted in growth reduction of Populus x canescens. Nutrient element contents in the foliage of plants under salt stress were different from that of control. The foliar N-concentrations of plants under salt stress were not affected. Contents of Na under salt stress were 120 times as much as that under control. However, contents of S, K, P, Ca, Mg, Fe, Mn under salt stress were less than that under control. Salt stress caused damage in the PSII reaction centers, i.e. photo-inhibition couldn't be repaired under dark situation. The yield of chlorophyll fluorescence showed that several parameters associated with PSII functions, e.g. Fv/Fo, Fv/Fm were not influenced at the first stage of salt stress treatment. However, after a period of time, PSII functions were significantly inhibited, which led to the decrease of carbon assimilation. These results suggest that salt stress (150 mM NaCl) did not affect photosynthetic chlorophyll fluorescence of Populus x canescens immediately. After four day of salt stress, PSII reaction centres were seriously damaged during photo-inhibition.

  3. Scale dependence of disease impacts on quaking aspen (Populus tremuloides) mortality in the southwestern United States

    Science.gov (United States)

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2015-01-01

    Depending on how disease impacts tree exposure to risk, both the prevalence of disease and disease effects on survival may contribute to patterns of mortality risk across a species' range. Disease may accelerate tree species' declines in response to global change factors, such as drought, biotic interactions, such as competition, or functional traits, such as allometry. To assess the role of disease in mediating mortality risk in quaking aspen (Populus tremuloides), we developed hierarchical Bayesian models for both disease prevalence in live aspen stems and the resulting survival rates of healthy and diseased aspen near the species' southern range limit using 5088 individual trees on 281 United States Forest Service Forest Inventory and Analysis plots in the southwestern United States.

  4. Chemical responses to modified lignin composition in tension wood of hybrid poplar (Populus tremula x Populus alba).

    Science.gov (United States)

    Al-Haddad, Jameel M; Kang, Kyu-Young; Mansfield, Shawn D; Telewski, Frank W

    2013-04-01

    The effect of altering the expression level of the F5H gene was investigated in three wood tissues (normal, opposite and tension wood) in 1-year-old hybrid poplar clone 717 (Populus tremula × Populus alba L.), containing the F5H gene under the control of the C4H promoter. Elevated expression of the F5H gene in poplar has been previously reported to increase the percent syringyl content of lignin. The wild-type and three transgenic lines were inclined 45° for 3 months to induce tension wood formation. Tension and opposite wood from inclined trees, along with normal wood from control trees, were analyzed separately for carbohydrates, lignin, cellulose crystallinity and microfibril angle (MFA). In the wild-type poplar, the lignin in tension wood contained a significantly higher percentage of syringyl than normal wood or opposite wood. However, there was no significant difference in the percent syringyl content of the three wood types within each of the transgenic lines. Increasing the F5H gene expression caused an increase in the percent syringyl content and a slight decrease in the total lignin in normal wood. In tension wood, the addition of a gelatinous layer in the fiber walls resulted in a consistently lower percentage of total lignin in the tissue. Acid-soluble lignin was observed to increase by up to 2.3-fold in the transgenic lines. Compared with normal wood and opposite wood, cell wall crystallinity in tension wood was higher and the MFA was smaller, as expected, with no evidence of an effect from modifying the syringyl monomer ratio. Tension wood in all the lines contained consistently higher total sugar and glucose percentages when compared with normal wood within the respective lines. However, both sugar and glucose percentages were lower in the tension wood of transgenic lines when compared with the tension wood of wild-type trees. Evaluating the response of trees with altered syringyl content to gravity will improve our understanding of the changes

  5. Phenology and climate relationships in aspen (Populus tremuloides Michx.) forest and woodland communities of southwestern Colorado

    Science.gov (United States)

    Meier, Gretchen A.; Brown, Jesslyn F.; Evelsizer, Ross J.; Vogelmann, James E.

    2014-01-01

    Trembling aspen (Populus tremuloides Michx.) occurs over wide geographical, latitudinal, elevational, and environmental gradients, making it a favorable candidate for a study of phenology and climate relationships. Aspen forests and woodlands provide numerous ecosystem services, such as high primary productivity and biodiversity, retention and storage of environmental variables (precipitation, temperature, snow–water equivalent) that affect the spring and fall phenology of the aspen woodland communities of southwestern Colorado. We assessed the land surface phenology of aspen woodlands using two phenology indices, start of season time (SOST) and end of season time (EOST), from the U.S. Geological Survey (USGS) database of conterminous U.S. phenological indicators over an 11-year time period (2001–2011). These indicators were developed with 250 m resolution remotely sensed data from the Moderate Resolution Imaging Spectroradiometer processed to highlight vegetation response. We compiled data on SOST, EOST, elevation, precipitation, air temperature, and snow water equivalent (SWE) for selected sites having more than 80% cover by aspen woodland communities. In the 11-year time frame of our study, EOST had significant positive correlation with minimum fall temperature and significant negative correlation with fall precipitation. SOST had a significant positive correlation with spring SWE and spring maximum temperature.

  6. Lead uptake increases drought tolerance of wild type and transgenic poplar (Populus tremula x P. alba) overexpressing gsh 1.

    Science.gov (United States)

    Samuilov, Sladjana; Lang, Friedericke; Djukic, Matilda; Djunisijevic-Bojovic, Danijela; Rennenberg, Heinz

    2016-09-01

    Growth and development of plants largely depends on their adaptation ability in a changing climate. This is particularly true on heavy metal contaminated soils, but the interaction of heavy metal stress and climate on plant performance has not been intensively investigated. The aim of the present study was to elucidate if transgenic poplars (Populus tremula x P. alba) with enhanced glutathione content possess an enhanced tolerance to drought and lead (Pb) exposure (single and in combination) and if they are good candidates for phytoremediation of Pb contaminated soil. Lead exposure reduced growth and biomass accumulation only in above-ground tissue of wild type poplar, although most of lead accumulated in the roots. Drought caused a decline of the water content rather than reduced biomass production, while Pb counteracted this decline in the combined exposure. Apparently, metals such as Pb possess a protective function against drought, because they interact with abscisic acid dependent stomatal closure. Lead exposure decreased while drought increased glutathione content in leaves of both plant types. Lead accumulation was higher in the roots of transgenic plants, presumably as a result of chelation by glutathione. Water deprivation enhanced Pb accumulation in the roots, but Pb was subject to leakage out of the roots after re-watering. Transgenic plants showed better adaptation under mild drought plus Pb exposure partially due to improved glutathione synthesis. However, the transgenic plants cannot be considered as a good candidate for phytoremediation of Pb, due to its small translocation to the shoots and its leakage out of the roots upon re-watering.

  7. MORPHOLOGICAL AND ANATOMICAL STUDIES OF TRIPLOID FORMS OF ASPEN Морфолого-анатомическое исследование ценных форм триплоидной осины

    Directory of Open Access Journals (Sweden)

    Zontikov D. N.

    2013-06-01

    Full Text Available In this article, we have presented the survey of populations of triploid plant of Populus tremula L. genetic reserve of aspen in the area of Sharinsk in the Kostroma region. We have found the population of P. tremula L. not affected by the Phellinus tremulae Bond. et Boris fungus. The morphological and cytological analysis of plant samples taken from this genetic reserve in 1961 has been made. It has finally confirmed the triploid nature of the samples

  8. Aspen (Populus tremuloides Michx.) intake and preference by mammalian herbivores: the role of plant secondary compounds and nutritional context.

    Science.gov (United States)

    Villalba, Juan J; Burritt, Elizabeth A; St Clair, Samuel B

    2014-10-01

    Aspen (Populus tremuloides Michx.) has evolved a chemical defense system comprised of phenolic glycosides (PG), which effectively deter insect herbivory. However, much less is known about the role of PG and the nutritional quality of the associated plant community on aspen browse susceptibility to mammalian herbivores. In three successive periods during the growing season, we conducted experiments with sheep by offering leaves from two aspen stands with different concentrations of PG (LOW, HIGH) or aspen leaves vs. leaves from a forb (Utah pea, Lathyrus pauciflorus) or a grass (smooth brome, Bromus inermis Leyss.) growing in an aspen understory. Intake of aspen (19 to 35 % PG) was low in all periods (1 to 6 g/Kg(0.75) in 2 hr) supporting the notion that aspen's defense system may contribute to its ecological success. However, lambs ate larger amounts of LOW than of HIGH suggesting that sheep could discriminate between aspen stands with different concentrations of PG, even when both stands were relatively well defended. Concentration of nutrients and chemical defenses in aspen leaves remained fairly stable across the growing season, and preference for aspen increased over the growing season. In contrast, preference for the forb and the grass decreased across the growing season in concert with a decline in the nutritional quality of these plants. The data suggest that nutritional context of aspen and associated forage species drove preference more than contrasts in defense chemistry of aspen. There may be periods of "susceptibility" of aspen use by mammalian herbivores, despite high concentrations of chemical defenses, which can potentially be targeted by management to reduce aspen herbivory.

  9. Disentangling herbivore impacts on Populus tremuloides: a comparison of native ungulates and cattle in Canada's Aspen Parkland.

    Science.gov (United States)

    Bork, Edward W; Carlyle, Cameron N; Cahill, James F; Haddow, Rae E; Hudson, Robert J

    2013-11-01

    Ungulates impact woody species' growth and abundance but little is understood about the comparative impacts of different ungulate species on forest expansion in savanna environments. Replacement of native herbivore guilds with livestock [i.e., beef cattle (Bos taurus)] has been hypothesized as a factor facilitating trembling aspen (Populus tremuloides Michx.) encroachment into grasslands of the Northern Great Plains. We used a controlled herbivory study in the Parklands of western Canada to compare the impact of native ungulates and cattle on aspen saplings. Native ungulate treatments included a mixed species guild and sequences of herbivory by different ungulates [bison (Bison bison subsp. bison), elk (Cervus elaphus) then deer (Odocoileus hemionus); or deer, elk, then bison]. Herbivory treatments were replicated in three pastures, within which sets of 40 marked aspen saplings (aspen stand. Stems were assessed for mortality and incremental damage (herbivory, leader breakage, stem abrasion and trampling). Final mortality was greater with exposure to any type of herbivore, but remained similar between ungulate treatments. However, among all treatments, the growth of aspen was highest with exposure only to cattle. Herbivory of aspen was attributed primarily to elk within the native ungulate treatments, with other forms of physical damage, and ultimately sapling mortality, associated with exposure to bison. Overall, these results indicate that native ungulates, specifically elk and bison, have more negative impacts on aspen saplings and provide evidence that native and domestic ungulates can have different functional effects on woody plant dynamics in savanna ecosystems.

  10. Microarray and suppression subtractive hybridization analyses of gene expression in hybrid poplar (Populus alba × Populus tremula var. glandulosa) cell suspension cultures after exposure to NaCl.

    Science.gov (United States)

    Bae, Eun-Kyung; Lee, Hyoshin; Lee, Jae-Soon; Noh, Eun-Woon; Choi, Young-Im; Lee, Byung-Hyun; Choi, Dong-Woog

    2012-09-01

    The gene expression profiles of hybrid poplar (Populus alba × Populus tremula var. glandulosa) cells in suspension culture after exposure to salinity (NaCl) induced stress were examined by constructing two suppression subtractive hybridization (SSH) libraries. cDNA from non-treated cells was used as a driver and cDNA samples from cell suspension cultures exposed to 150 mM NaCl for 2 or 10 h were used as testers. Randomly selected clones from each SSH library were sequenced and 727 high-quality expressed sequence tags (ESTs) were obtained and analyzed. Four novel ESTs were identified. Between the two libraries, 542 unique SSH clones were selected for placement on a cDNA microarray. In total, 18 differentially expressed genes were identified with 4 and 12 genes being significantly differentially expressed 2 and 10 h after the treatment, respectively. Genes related to metabolism and protein synthesis and several genes whose protein products are implicated in salt or other abiotic stress-related responses were expressed in the salt-stressed cells.

  11. Hydraulic conductivity and aquaporin transcription in roots of trembling aspen (Populus tremuloides) seedlings colonized by Laccaria bicolor.

    Science.gov (United States)

    Xu, Hao; Cooke, Janice E K; Kemppainen, Minna; Pardo, Alejandro G; Zwiazek, Janusz J

    2016-07-01

    Ectomycorrhizal fungi have been reported to increase root hydraulic conductivity (L pr) by altering apoplastic and plasma membrane intrinsic protein (PIP)-mediated cell-to-cell water transport pathways in associated roots, or to have little effect on root water transport, depending on the interacting species and imposed stresses. In this study, we investigated the water transport properties and PIP transcription in roots of aspen (Populus tremuloides) seedlings colonized by the wild-type strain of Laccaria bicolor and by strains overexpressing a major fungal water-transporting aquaporin JQ585595. Inoculation of aspen seedlings with L. bicolor resulted in about 30 % colonization rate of root tips, which developed dense mantle and the Hartig net that was restricted in the modified root epidermis. Transcript abundance of the aspen aquaporins PIP1;2, PIP2;1, and PIP2;2 decreased in colonized root tips. Root colonization by JQ585595-overexpressing strains had no significant impact on seedling shoot water potentials, gas exchange, or dry mass; however, it led to further decrease in transcript abundance of PIP1;2 and PIP2;3 and the significantly lower L pr than in non-inoculated roots. These results, taken together with our previous study that showed enhanced root water hydraulics of L. bicolor-colonized white spruce (Picea glauca), suggest that the impact of L. bicolor on root hydraulics varies by the ectomycorrhiza-associated tree species.

  12. Abaxial Greening Phenotype in Hybrid Aspen.

    Science.gov (United States)

    Nowak, Julia S; Douglas, Carl J; Cronk, Quentin C B

    2013-04-24

    The typical angiosperm leaf, as in Arabidopsis, is bifacial consisting of top (adaxial) and bottom (abaxial) surfaces readily distinguishable by the underlying cell type (palisade and spongy mesophyll, respectively). Species of the genus Populus have leaves that are either conventionally bifacial or isobilateral. Isobilateral leaves have palisade mesophyll on the top and bottom of the leaf, making the two sides virtually indistinguishable at the macroscopic level. In poplars this has been termed the "abaxial greening" phenotype. Previous work has implicated ASYMMETRIC LEAVES1 (AS1) as an essential determinant of palisade mesophyll development. This gene, as well as other genes (84 in all) putatively involved in setting the dorsiventral axis of leaves, were investigated in two Populus species: black cottonwood (Populus trichocarpa) and hybrid aspen (P. tremula x tremuloides), representative of each leaf type (bifacial and isobilateral, respectively). Poplar orthologs of AS1 have significantly higher expression in aspen leaf blade and lower in the petiole, suggestive of a potential role in the isobilateral leaf phenotype consistent with the previously observed phenotypes. Furthermore, an ABERRANT TESTA SHAPE (ATS) ortholog has significantly lower expression in aspen leaf tissue, also suggesting a possible contribution of this gene to abaxial greening.

  13. Abaxial Greening Phenotype in Hybrid Aspen

    Directory of Open Access Journals (Sweden)

    Julia S. Nowak

    2013-04-01

    Full Text Available The typical angiosperm leaf, as in Arabidopsis, is bifacial consisting of top (adaxial and bottom (abaxial surfaces readily distinguishable by the underlying cell type (palisade and spongy mesophyll, respectively. Species of the genus Populus have leaves that are either conventionally bifacial or isobilateral. Isobilateral leaves have palisade mesophyll on the top and bottom of the leaf, making the two sides virtually indistinguishable at the macroscopic level. In poplars this has been termed the “abaxial greening” phenotype. Previous work has implicated ASYMMETRIC LEAVES1 (AS1 as an essential determinant of palisade mesophyll development. This gene, as well as other genes (84 in all putatively involved in setting the dorsiventral axis of leaves, were investigated in two Populus species: black cottonwood (Populus trichocarpa and hybrid aspen (P. tremula x tremuloides, representative of each leaf type (bifacial and isobilateral, respectively. Poplar orthologs of AS1 have significantly higher expression in aspen leaf blade and lower in the petiole, suggestive of a potential role in the isobilateral leaf phenotype consistent with the previously observed phenotypes. Furthermore, an ABERRANT TESTA SHAPE (ATS ortholog has significantly lower expression in aspen leaf tissue, also suggesting a possible contribution of this gene to abaxial greening.

  14. Influence of Genotype, Environment, and Gypsy Moth Herbivory on Local and Systemic Chemical Defenses in Trembling Aspen (Populus tremuloides).

    Science.gov (United States)

    Rubert-Nason, Kennedy F; Couture, John J; Major, Ian T; Constabel, C Peter; Lindroth, Richard L

    2015-07-01

    Numerous studies have explored the impacts of intraspecific genetic variation and environment on the induction of plant chemical defenses by herbivory. Relatively few, however, have considered how those factors affect within-plant distribution of induced defenses. This work examined the impacts of plant genotype and soil nutrients on the local and systemic phytochemical responses of trembling aspen (Populus tremuloides) to defoliation by gypsy moth (Lymantria dispar). We deployed larvae onto foliage on individual tree branches for 15 days and then measured chemistry in leaves from: 1) branches receiving damage, 2) undamaged branches of insect-damaged trees, and 3) branches of undamaged control trees. The relationship between post-herbivory phytochemical variation and insect performance also was examined. Plant genotype, soil nutrients, and damage all influenced phytochemistry, with genotype and soil nutrients being stronger determinants than damage. Generally, insect damage decreased foliar nitrogen, increased levels of salicinoids and condensed tannins, but had little effect on levels of a Kunitz trypsin inhibitor, TI3. The largest damage-mediated tannin increases occurred in leaves on branches receiving damage, whereas the largest salicinoid increases occurred in leaves of adjacent, undamaged branches. Foliar nitrogen and the salicinoid tremulacin had the strongest positive and negative relationships, respectively, with insect growth. Overall, plant genetics and environment concomitantly influenced both local and systemic phytochemical responses to herbivory. These findings suggest that herbivory can contribute to phytochemical heterogeneity in aspen foliage, which may in turn influence future patterns of herbivory and nutrient cycling over larger spatial scales.

  15. Genetic diversity in aspen and its relation to arthropod abundance.

    Science.gov (United States)

    Zhang, Chunxia; Vornam, Barbara; Volmer, Katharina; Prinz, Kathleen; Kleemann, Frauke; Köhler, Lars; Polle, Andrea; Finkeldey, Reiner

    2014-01-01

    The ecological consequences of biodiversity have become a prominent public issue. Little is known on the effect of genetic diversity on ecosystem services. Here, a diversity experiment was established with European and North American aspen (Populus tremula, P. tremuloides) planted in plots representing either a single deme only or combinations of two, four and eight demes. The goals of this study were to explore the complex inter- and intraspecific genetic diversity of aspen and to then relate three measures for diversity (deme diversity, genetic diversity determined as Shannon index or as expected heterozygosity) to arthropod abundance. Microsatellite and AFLP markers were used to analyze the genetic variation patterns within and between the aspen demes and deme mixtures. Large differences were observed regarding the genetic diversity within demes. An analysis of molecular variance revealed that most of the total genetic diversity was found within demes, but the genetic differentiation among demes was also high. The complex patterns of genetic diversity and differentiation resulted in large differences of the genetic variation within plots. The average diversity increased from plots with only one deme to plots with two, four, and eight demes, respectively and separated plots with and without American aspen. To test whether intra- and interspecific diversity impacts on ecosystem services, arthropod abundance was determined. Increasing genetic diversity of aspen was related to increasing abundance of arthropods. However, the relationship was mainly driven by the presence of American aspen suggesting that species identity overrode the effect of intraspecific variation of European aspen.

  16. A simple PCR-based marker to determine sex in aspen.

    Science.gov (United States)

    Pakull, B; Kersten, B; Lüneburg, J; Fladung, M

    2015-01-01

    The genus Populus features a genetically controlled sex determination system, located on chromosome 19. However, different Populus species vary in the position of the sex-linked region on the respective chromosome and the apparent heterogametic sex, and the precise mechanism of sex determination in Populus is still unknown. Using next generation sequencing of pooled samples of male and female aspens, we identified the aspen homologue of the P. trichocarpa gene Potri.019G047300 ('TOZ19') to be male-specific. While in P. tremuloides, the complete gene is missing in the genome of female plants, a short fragment of the 3'-part of the gene is still present in P. tremula females. The male-specific presence and transcription of TOZ19 was further verified using PCR in various different aspen individuals and RT-PCR expression analysis. TOZ19 is potentially involved in early steps of flower development, and represents an interesting candidate gene for involvement in sex determination in aspen. Regardless of its role as candidate gene, TOZ19 represents an ideal marker for determination of the sex of non-flowering aspen individuals or seedlings.

  17. Can elevated CO2 and ozone shift the genetic composition of aspen (Populus tremuloides) stands?

    Science.gov (United States)

    Moran, Emily V; Kubiske, Mark E

    2013-04-01

    The world's forests are currently exposed to increasing concentrations of carbon dioxide (CO2) and ozone (O3). Both pollutants can potentially exert a selective effect on plant populations. This, in turn, may lead to changes in ecosystem properties, such as carbon sequestration. Here, we report how elevated CO2 and O3 affect the genetic composition of a woody plant population via altered survival. Using data from the Aspen free-air CO2 enrichment (FACE) experiment (in which aspen clones were grown in factorial combinations of CO2 and O3), we develop a hierarchical Bayesian model of survival. We also examine how survival differences between clones could affect pollutant responses in the next generation. Our model predicts that the relative abundance of the tested clones, given equal initial abundance, would shift under either elevated CO2 or O3 as a result of changing survival rates. Survival was strongly affected by between-clone differences in growth responses. Selection could noticeably decrease O3 sensitivity in the next generation, depending on the heritability of growth responses and the distribution of seed production. The response to selection by CO2, however, is likely to be small. Our results suggest that the changing atmospheric composition could shift the genotypic composition and average pollutant responses of tree populations over moderate timescales.

  18. Spring leaf flush in aspen (Populus tremuloides) clones is altered by long-term growth at elevated carbon dioxide and elevated ozone concentration.

    Science.gov (United States)

    McGrath, Justin M; Karnosky, David F; Ainsworth, Elizabeth A

    2010-04-01

    Early spring leaf out is important to the success of deciduous trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how long-term growth at elevated carbon dioxide concentration ([CO(2)]) and elevated ozone concentration ([O(3)]) altered leaf area index development in a closed Populus tremuloides (aspen) canopy. This work was done at the Aspen FACE experiment where aspen clones have been grown since 1997 in conditions simulating the [CO(2)] and [O(3)] predicted for approximately 2050. The responses of two clones were compared during the first month of spring leaf out when CO(2) fumigation had begun, but O(3) fumigation had not. Trees in elevated [CO(2)] plots showed a stimulation of leaf area index (36%), while trees in elevated [O(3)] plots had lower leaf area index (-20%). While individual leaf area was not significantly affected by elevated [CO(2)], the photosynthetic operating efficiency of aspen leaves was significantly improved (51%). There were no significant differences in the way that the two aspen clones responded to elevated [CO(2)]; however, the two clones responded differently to long-term growth at elevated [O(3)]. The O(3)-sensitive clone, 42E, had reduced individual leaf area when grown at elevated [O(3)] (-32%), while the tolerant clone, 216, had larger mature leaf area at elevated [O(3)] (46%). These results indicate a clear difference between the two clones in their long-term response to elevated [O(3)], which could affect competition between the clones, and result in altered genotypic composition in future atmospheric conditions.

  19. ASSESSMENT METHOD OF STERILIZATION AND MINERAL COMPOSITION OF NUTRIENT MEDIUM ON EFFICIENT CULTIVATION OF POPULUS TREMULA L. IN TISSUE CULTURE Оценка способа стерилизации и минерального состава питательных сред на эффективность культивирования Populus tremula L. в условиях in vitro

    Directory of Open Access Journals (Sweden)

    Zontikov D. N.

    2013-09-01

    Full Text Available A comparison of quantitative and qualitative performance of the selected clones of breeding of A.S. Yablokov and S.N. Bagaev has been made. At the same forest conditions, the clones are much higher than regular at reserves, the absolute completeness, the average heights and diameters of trees. Gigantic forms of P. tremula L. are resistant to infectious diseases, and at the fifth grade are characterized by good sanitary condition. We have also shown the economic feasibility of using of fast-growing clones in the genetic reserve for the organization of giant aspen of P. tremula L. plantation

  20. The efficacy of six elite isolates of the fungus Chondrostereum purpureum against the sprouting of European aspen.

    Science.gov (United States)

    Hamberg, Leena; Hantula, Jarkko

    2016-04-15

    The sprouting of broad-leaved trees after cutting is problematic in forest regeneration areas, along roads and railways, under electric power and above gas pipe lines. In Finland, one of the most difficult species to control in these areas is the European aspen (Populus tremula), which produces both stump sprouts and root suckers after saplings have been cut. In this study, we investigated whether a decay fungus of broad-leaved trees, Chondrostereum purpureum, could be used as a biological control agent against aspen sprouting. The efficacy of six elite strains of C. purpureum (improved earlier in a breeding process) was investigated on aspen for three years. The most efficient C. purpureum strain, R53, tested earlier on birch (Betula pendula and B. pubescens), was efficient in causing mortality of aspen stumps and preventing the development of root suckers. With this strain, stump mortality was 78%, while significantly lower in control stumps which were cut only (47%). Aspen trees in the vicinity of the treatments (within a 10 m radius around each sapling) decreased the efficacy of C. purpureum. This study shows that the decay fungus C. purpureum can successfully be used in the sprout control of aspen saplings.

  1. Aspen SUCROSE TRANSPORTER3 allocates carbon into wood fibers.

    Science.gov (United States)

    Mahboubi, Amir; Ratke, Christine; Gorzsás, András; Kumar, Manoj; Mellerowicz, Ewa J; Niittylä, Totte

    2013-12-01

    Wood formation in trees requires carbon import from the photosynthetic tissues. In several tree species, including Populus species, the majority of this carbon is derived from sucrose (Suc) transported in the phloem. The mechanism of radial Suc transport from phloem to developing wood is not well understood. We investigated the role of active Suc transport during secondary cell wall formation in hybrid aspen (Populus tremula × Populus tremuloides). We show that RNA interference-mediated reduction of PttSUT3 (for Suc/H(+) symporter) during secondary cell wall formation in developing wood caused thinner wood fiber walls accompanied by a reduction in cellulose and an increase in lignin. Suc content in the phloem and developing wood was not significantly changed. However, after (13)CO2 assimilation, the SUT3RNAi lines contained more (13)C than the wild type in the Suc-containing extract of developing wood. Hence, Suc was transported into developing wood, but the Suc-derived carbon was not efficiently incorporated to wood fiber walls. A yellow fluorescent protein:PttSUT3 fusion localized to plasma membrane, suggesting that reduced Suc import into developing wood fibers was the cause of the observed cell wall phenotype. The results show the importance of active Suc transport for wood formation in a symplasmically phloem-loading tree species and identify PttSUT3 as a principal transporter for carbon delivery into secondary cell wall-forming wood fibers.

  2. Gibberellins inhibit adventitious rooting in hybrid aspen and Arabidopsis by affecting auxin transport.

    Science.gov (United States)

    Mauriat, Mélanie; Petterle, Anna; Bellini, Catherine; Moritz, Thomas

    2014-05-01

    Knowledge of processes involved in adventitious rooting is important to improve both fundamental understanding of plant physiology and the propagation of numerous plants. Hybrid aspen (Populus tremula × tremuloïdes) plants overexpressing a key gibberellin (GA) biosynthesis gene (AtGA20ox1) grow rapidly but have poor rooting efficiency, which restricts their clonal propagation. Therefore, we investigated the molecular basis of adventitious rooting in Populus and the model plant Arabidopsis. The production of adventitious roots (ARs) in tree cuttings is initiated from the basal stem region, and involves the interplay of several endogenous and exogenous factors. The roles of several hormones in this process have been characterized, but the effects of GAs have not been fully investigated. Here, we show that a GA treatment negatively affects the numbers of ARs produced by wild-type hybrid aspen cuttings. Furthermore, both hybrid aspen plants and intact Arabidopsis seedlings overexpressing AtGA20ox1, PttGID1.1 or PttGID1.3 genes (with a 35S promoter) produce few ARs, although ARs develop from the basal stem region of hybrid aspen and the hypocotyl of Arabidopsis. In Arabidopsis, auxin and strigolactones are known to affect AR formation. Our data show that the inhibitory effect of GA treatment on adventitious rooting is not mediated by perturbation of the auxin signalling pathway, or of the strigolactone biosynthetic and signalling pathways. Instead, GAs appear to act by perturbing polar auxin transport, in particular auxin efflux in hybrid aspen, and both efflux and influx in Arabidopsis.

  3. Cloning and Overproduction of Gibberellin 3-Oxidase in Hybrid Aspen Trees. Effects on Gibberellin Homeostasis and Development1

    Science.gov (United States)

    Israelsson, Maria; Mellerowicz, Ewa; Chono, Makiko; Gullberg, Jonas; Moritz, Thomas

    2004-01-01

    To broaden our understanding of gibberellin (GA) biosynthesis and the mechanism whereby GA homeostasis is maintained in plants, we have investigated the degree to which the enzyme GA 3-oxidase (GA3ox) limits the formation of bioactive GAs in elongating shoots of hybrid aspen (Populus tremula × Populus tremuloides). We describe the cloning of a hybrid aspen GA3ox and its functional characterization, which confirmed that it has 3β-hydroxylation activity and more efficiently converts GA9 to GA4 than GA20 to GA1. To complement previous studies, in which transgenic GA 20-oxidase (GA20ox) overexpressers were found to produce 20-fold higher bioactive GA levels and subsequently grew faster than wild-type plants, we overexpressed an Arabidopsis GA3ox in hybrid aspen. The generated GA3ox overexpresser lines had increased 3β-hydroxylation activity but exhibited no major changes in morphology. The nearly unaltered growth pattern was associated with relatively small changes in GA1 and GA4 levels, although tissue-dependent differences were observed. The absence of increases in bioactive GA levels did not appear to be due to feedback or feed-forward regulation of dioxygenase transcripts, according to semiquantitative reverse transcription polymerase chain reaction analysis of PttGA20ox1, PttGA3ox1, and two putative PttGA2ox genes. We conclude that 20-oxidation is the limiting step, rather than 3β-hydroxylation, in the formation of GA1 and GA4 in elongating shoots of hybrid aspen, and that ectopic GA3ox expression alone cannot increase the flux toward bioactive GAs. Finally, several lines of evidence now suggest that GA4 has a more pivotal role in the tree hybrid aspen than previously believed. PMID:15122019

  4. Cloning and overproduction of gibberellin 3-oxidase in hybrid aspen trees. Effects on gibberellin homeostasis and development.

    Science.gov (United States)

    Israelsson, Maria; Mellerowicz, Ewa; Chono, Makiko; Gullberg, Jonas; Moritz, Thomas

    2004-05-01

    To broaden our understanding of gibberellin (GA) biosynthesis and the mechanism whereby GA homeostasis is maintained in plants, we have investigated the degree to which the enzyme GA 3-oxidase (GA3ox) limits the formation of bioactive GAs in elongating shoots of hybrid aspen (Populus tremula x Populus tremuloides). We describe the cloning of a hybrid aspen GA3ox and its functional characterization, which confirmed that it has 3beta-hydroxylation activity and more efficiently converts GA9 to GA4 than GA20 to GA1. To complement previous studies, in which transgenic GA 20-oxidase (GA20ox) overexpressers were found to produce 20-fold higher bioactive GA levels and subsequently grew faster than wild-type plants, we overexpressed an Arabidopsis GA3ox in hybrid aspen. The generated GA3ox overexpresser lines had increased 3beta-hydroxylation activity but exhibited no major changes in morphology. The nearly unaltered growth pattern was associated with relatively small changes in GA1 and GA4 levels, although tissue-dependent differences were observed. The absence of increases in bioactive GA levels did not appear to be due to feedback or feed-forward regulation of dioxygenase transcripts, according to semiquantitative reverse transcription polymerase chain reaction analysis of PttGA20ox1, PttGA3ox1, and two putative PttGA2ox genes. We conclude that 20-oxidation is the limiting step, rather than 3beta-hydroxylation, in the formation of GA1 and GA4 in elongating shoots of hybrid aspen, and that ectopic GA3ox expression alone cannot increase the flux toward bioactive GAs. Finally, several lines of evidence now suggest that GA4 has a more pivotal role in the tree hybrid aspen than previously believed.

  5. Tree age-dependent changes in photosynthetic and respiratory CO2 exchange in leaves of micropropagated diploid, triploid and hybrid aspen.

    Science.gov (United States)

    Pärnik, Tiit; Ivanova, Hiie; Keerberg, Olav; Vardja, Rael; Niinemets, Ulo

    2014-06-01

    The growth rate of triploid European aspen (Populus tremula L.) and hybrid aspen (P. tremula × Populus tremuloides Michx.) significantly exceeds that of diploid aspen, but the underlying physiological controls of the superior growth rates of these genotypes are not known. We tested the hypothesis that the superior growth rate of triploid and hybrid aspen reflects their greater net photosynthesis rate. Micropropagated clonal plants varying in age from 2.5 to 19 months were used to investigate the ploidy and plant age interaction. The quantum yield of net CO2 fixation (Φ) in leaves of young 2.5-month-old hybrid aspen was lower than that of diploid and triploid trees. However, Φ in 19-month-old hybrid aspen was equal to that in triploid aspen and higher than that in diploid aspen. Φ and the rate of light-saturated net photosynthesis (ANS) increased with plant age, largely due to higher leaf dry mass per unit area in older plants. ANS in leaves of 19-month-old trees was highest in hybrid, medium in triploid and lowest in diploid aspen. Light-saturated photosynthesis had a broad temperature optimum between 20 and 35 °C. Rate of respiration in the dark (RDS) did not vary among the genotypes in 2.5-month-old plants, and the shape of the temperature response was also similar. RDS increased with plant age, but RDS was still not significantly different among the leaves of 19-month-old diploid and triploid aspen, but it was significantly lower in leaves of 19-month-old hybrid plants. The initial differences in the growth of plants with different ploidy were minor up to the age of 19 months, but during the next 2 years, the growth rate of hybrid aspen exceeded that of triploid plants by 2.7 times and of diploid plants by five times, in line with differences in ANS of 19-month-old plants of these species. It is suggested that differences in photosynthesis and growth became more pronounced with tree aging, indicating that ontogeny plays a key role in the expression of

  6. Testing Transgenic Aspen Plants with bar Gene for Herbicide Resistance under Semi-natural Conditions.

    Science.gov (United States)

    Lebedev, V G; Faskhiev, V N; Kovalenko, N P; Shestibratov, K A; Miroshnikov, A I

    2016-01-01

    Obtaining herbicide resistant plants is an important task in the genetic engineering of forest trees. Transgenic European aspen plants (Populus tremula L.) expressing the bar gene for phosphinothricin resistance have been produced using Agrobacterium tumefaciens-mediated transformation. Successful genetic transformation was confirmed by PCR analysis for thirteen lines derived from two elite genotypes. In 2014-2015, six lines were evaluated for resistance to herbicide treatment under semi-natural conditions. All selected transgenic lines were resistant to the herbicide Basta at doses equivalent to 10 l/ha (twofold normal field dosage) whereas the control plants died at 2.5 l/ha. Foliar NH4-N concentrations in transgenic plants did not change after treatment. Extremely low temperatures in the third ten-day period of October 2014 revealed differences in freeze tolerance between the lines obtained from Pt of f2 aspen genotypes. Stable expression of the bar gene after overwintering outdoors was confirmed by RT-PCR. On the basis of the tests, four transgenic aspen lines were selected. The bar gene could be used for retransformation of transgenic forest trees expressing valuable traits, such as increased productivity.

  7. DECAY RESISTANCE AND PHYSICAL PROPERTIES OF OIL HEAT TREATED ASPEN WOOD

    Directory of Open Access Journals (Sweden)

    Behzad Bazyar

    2011-12-01

    Full Text Available The decay resistance of oil-heat treated aspen wood (Populus tremula l. against white rot fungi (Coriolus versicolor and brown rot fungi (Coniophora puteana was investigated. Three different temperature stages and two time levels for oil heat treatment for the selection of optimum conditions were determined. Linseed oil as a heating medium was used. The mass loss of treated samples that were exposed to both fungi was significantly lower than that of the control samples. Results also showed improvement in dimensional stability after oil heat treatment. Decay resistance and dimensional stability of aspen wood were increased significantly with temperature increasing, but time seemed to have no effect on those properties. Oil heat treatment is a suitable method to improve decay resistance of aspen wood as it reduced the mass loss by 71% and 77% against Coriolus versicolor and Coniophora puteana compared with control samples, respectively. On the other hand, oil heat treatment improved the dimensional stability by about 20.5%.

  8. Transgenic hybrid aspen trees with increased gibberellin (GA) concentrations suggest that GA acts in parallel with FLOWERING LOCUS T2 to control shoot elongation.

    Science.gov (United States)

    Eriksson, Maria E; Hoffman, Daniel; Kaduk, Mateusz; Mauriat, Mélanie; Moritz, Thomas

    2015-02-01

    Bioactive gibberellins (GAs) have been implicated in short day (SD)-induced growth cessation in Populus, because exogenous applications of bioactive GAs to hybrid aspens (Populus tremula × tremuloides) under SD conditions delay growth cessation. However, this effect diminishes with time, suggesting that plants may cease growth following exposure to SDs due to a reduction in sensitivity to GAs. In order to validate and further explore the role of GAs in growth cessation, we perturbed GA biosynthesis or signalling in hybrid aspen plants by overexpressing AtGA20ox1, AtGA2ox2 and PttGID1.3 (encoding GA biosynthesis enzymes and a GA receptor). We found trees with elevated concentrations of bioactive GA, due to overexpression of AtGA20ox1, continued to grow in SD conditions and were insensitive to the level of FLOWERING LOCUS T2 (FT2) expression. As transgenic plants overexpressing the PttGID1.3 GA receptor responded in a wild-type (WT) manner to SD conditions, this insensitivity did not result from limited receptor availability. As high concentrations of bioactive GA during SD conditions were sufficient to sustain shoot elongation growth in hybrid aspen trees, independent of FT2 expression levels, we conclude elongation growth in trees is regulated by both GA- and long day-responsive pathways, similar to the regulation of flowering in Arabidopsis thaliana.

  9. A genome-wide screen for ethylene-induced ethylene response factors (ERFs) in hybrid aspen stem identifies ERF genes that modify stem growth and wood properties.

    Science.gov (United States)

    Vahala, Jorma; Felten, Judith; Love, Jonathan; Gorzsás, András; Gerber, Lorenz; Lamminmäki, Airi; Kangasjärvi, Jaakko; Sundberg, Björn

    2013-10-01

    Ethylene Response Factors (ERFs) are a large family of transcription factors that mediate responses to ethylene. Ethylene affects many aspects of wood development and is involved in tension wood formation. Thus ERFs could be key players connecting ethylene action to wood development. We identified 170 gene models encoding ERFs in the Populus trichocarpa genome. The transcriptional responses of ERF genes to ethylene treatments were determined in stem tissues of hybrid aspen (Populus tremula × tremuloides) by qPCR. Selected ethylene-responsive ERFs were overexpressed in wood-forming tissues and characterized for growth and wood chemotypes by FT-IR. Fifty ERFs in Populus showed more than five-fold increased transcript accumulation in response to ethylene treatments. Twenty-six ERFs were selected for further analyses. A majority of these were induced during tension wood formation. Overexpression of ERFs 18, 21, 30, 85 and 139 in wood-forming tissues of hybrid aspen modified the wood chemotype. Moreover, overexpression of ERF139 caused a dwarf-phenotype with altered wood development, and overexpression of ERF18, 34 and 35 slightly increased stem diameter. We identified ethylene-induced ERFs that respond to tension wood formation, and modify wood formation when overexpressed. This provides support for their role in ethylene-mediated regulation of wood development.

  10. Suppression of xylan endotransglycosylase PtxtXyn10A affects cellulose microfibril angle in secondary wall in aspen wood.

    Science.gov (United States)

    Derba-Maceluch, Marta; Awano, Tatsuya; Takahashi, Junko; Lucenius, Jessica; Ratke, Christine; Kontro, Inkeri; Busse-Wicher, Marta; Kosik, Ondrej; Tanaka, Ryo; Winzéll, Anders; Kallas, Åsa; Leśniewska, Joanna; Berthold, Fredrik; Immerzeel, Peter; Teeri, Tuula T; Ezcurra, Ines; Dupree, Paul; Serimaa, Ritva; Mellerowicz, Ewa J

    2015-01-01

    Certain xylanases from family GH10 are highly expressed during secondary wall deposition, but their function is unknown. We carried out functional analyses of the secondary-wall specific PtxtXyn10A in hybrid aspen (Populus tremula × tremuloides). PtxtXyn10A function was analysed by expression studies, overexpression in Arabidopsis protoplasts and by downregulation in aspen. PtxtXyn10A overexpression in Arabidopsis protoplasts resulted in increased xylan endotransglycosylation rather than hydrolysis. In aspen, the enzyme was found to be proteolytically processed to a 68 kDa peptide and residing in cell walls. Its downregulation resulted in a corresponding decrease in xylan endotransglycosylase activity and no change in xylanase activity. This did not alter xylan molecular weight or its branching pattern but affected the cellulose-microfibril angle in wood fibres, increased primary growth (stem elongation, leaf formation and enlargement) and reduced the tendency to form tension wood. Transcriptomes of transgenic plants showed downregulation of tension wood related genes and changes in stress-responsive genes. The data indicate that PtxtXyn10A acts as a xylan endotransglycosylase and its main function is to release tensional stresses arising during secondary wall deposition. Furthermore, they suggest that regulation of stresses in secondary walls plays a vital role in plant development.

  11. Management of aspen plant communities on the National Elk Refuge, Wyoming

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — There are 1,860 acres (753 ha) of aspen (Populus tremuloides) plant communities on the National Elk Refuge (NER). Aspen is an important tree species on the Refuge,...

  12. Bryophyte species richness on retention aspens recovers in time but community structure does not.

    Directory of Open Access Journals (Sweden)

    Anna Oldén

    Full Text Available Green-tree retention is a forest management method in which some living trees are left on a logged area. The aim is to offer 'lifeboats' to support species immediately after logging and to provide microhabitats during and after forest re-establishment. Several studies have shown immediate decline in bryophyte diversity after retention logging and thus questioned the effectiveness of this method, but longer term studies are lacking. Here we studied the epiphytic bryophytes on European aspen (Populus tremula L. retention trees along a 30-year chronosequence. We compared the bryophyte flora of 102 'retention aspens' on 14 differently aged retention sites with 102 'conservation aspens' on 14 differently aged conservation sites. We used a Bayesian community-level modelling approach to estimate the changes in bryophyte species richness, abundance (area covered and community structure during 30 years after logging. Using the fitted model, we estimated that two years after logging both species richness and abundance of bryophytes declined, but during the following 20-30 years both recovered to the level of conservation aspens. However, logging-induced changes in bryophyte community structure did not fully recover over the same time period. Liverwort species showed some or low potential to benefit from lifeboating and high potential to re-colonise as time since logging increases. Most moss species responded similarly, but two cushion-forming mosses benefited from the logging disturbance while several weft- or mat-forming mosses declined and did not re-colonise in 20-30 years. We conclude that retention trees do not function as equally effective lifeboats for all bryophyte species but are successful in providing suitable habitats for many species in the long-term. To be most effective, retention cuts should be located adjacent to conservation sites, which may function as sources of re-colonisation and support the populations of species that require old

  13. Somatic Embryogenesis from Cell Suspension Cultures of Aspen Clone

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Suspension cultures initiated from callus derived from petiole explants of aspen hybrid (Populus tremuloides × P.tremula) produced somatic embryos. Callus was induced on a MS medium supplemented with 5 mg·L-1 2,4-D and 0.05 mg·L-1 zeatin under light conditions. Embryogenic calli were obtained when a subsequent subculture of calli was suspended in the same basal medium with 10 mg·L-1 2,4-D. The highest number of globular embryos were induced from embryogenic calli by cell suspension culture in a MS liquid medium supplemented with 10 mg·L-1 2,4-D. Genotype and 2,4-D concentration were vital to the induction of embryogenic calli producing competent cells. Embryogenic calli for each genotype were heterogeneous. Green calli with gel-like consistency could yield more competent cells than light yellow embryogenic calli. However, some globular embryos broke into slices and some developed abnormally after one month of culture under the same or other hormonal conditions.

  14. Artificially decreased vapour pressure deficit in field conditions modifies foliar metabolite profiles in birch and aspen.

    Science.gov (United States)

    Lihavainen, Jenna; Keinänen, Markku; Keski-Saari, Sarita; Kontunen-Soppela, Sari; Sõber, Anu; Oksanen, Elina

    2016-07-01

    Relative air humidity (RH) is expected to increase in northern Europe due to climate change. Increasing RH reduces the difference of water vapour pressure deficit (VPD) between the leaf and the atmosphere, and affects the gas exchange of plants. Little is known about the effects of decreased VPD on plant metabolism, especially under field conditions. This study was conducted to determine the effects of artificially decreased VPD on silver birch (Betula pendula Roth.) and hybrid aspen (Populus tremula L.×P. tremuloides Michx.) foliar metabolite and nutrient profiles in a unique free air humidity manipulation (FAHM) field experiment during the fourth season of humidity manipulation, in 2011. Long-term exposure to decreased VPD modified nutrient homeostasis in tree leaves, as demonstrated by a lower N concentration and N:P ratio in aspen leaves, and higher Na concentration and lower K:Na ratio in the leaves of both species in decreased VPD than in ambient VPD. Decreased VPD caused a shift in foliar metabolite profiles of both species, affecting primary and secondary metabolites. Metabolic adjustment to decreased VPD included elevated levels of starch and heptulose sugars, sorbitol, hemiterpenoid and phenolic glycosides, and α-tocopherol. High levels of carbon reserves, phenolic compounds, and antioxidants under decreased VPD may modify plant resistance to environmental stresses emerging under changing climate.

  15. Spatio-temporal dynamics of soil microbial biomass carbon in Populus tremula plantations in the southeast of Shandong Province%鲁东南杨树人工林土壤微生物生物量碳的时空动态

    Institute of Scientific and Technical Information of China (English)

    尉海东; 董彬

    2013-01-01

      为探讨土壤微生物生物量碳在鲁东南杨树Populus tremuloides人工林生态系统碳循环中的作用,利用氯仿熏蒸法测定了杨树人工林的土壤微生物生物量碳,研究了其时空动态及其与土壤有机碳的关系.结果表明:中龄杨树人工林和成熟杨树人工林土壤微生物生物量碳的变化范围分别为120.69~323.92 mg·kg-1和183.69~418.21 mg·kg-1,基本呈双峰趋势,生长季开始前下降、生长季结束时上升.土壤微生物生物量碳峰值均出现在4月和10月,最低值均出现在12月.0-20 cm土层土壤微生物生物量碳季节变化均较明显.两种林龄的杨树人工林土壤微生物生物量碳均随土层深度的增加而显著降低,土壤微生物生物量碳主要集中在0-40 cm土层,约占总土壤微生物生物量碳的89.77%~91.00%.成熟杨树人工林土壤微生物生物量碳显著高于中龄杨树人工林的.土壤微生物生物量碳与土壤有机碳含量呈极显著正相关(r2=0.946, p﹤0.01).微生物熵随土层深度的增加而升高,说明土壤有机碳逐渐由土壤表层向土壤深层转移,土壤处于碳积累状态,土壤呈碳汇功能.%Absract: To explore the role of soil microbial biomass carbon in ecosystem carbon cycle of Populus tremula plantations in the southeast of Shandong Province, the seasonal dynamics and vertical distributions of soil microbial biomass carbon in two ages Populus tremula plantations were studied by using the chloroform fumigation extraction method.And the relationships between soil microbial biomass carbon and soil organic carbon were also analyzed.Results showed that the microbial biomass carbon in middle-aged Populus tremuloides plantation(MAP)and mature Populus tremuloides plantation (MP) ranged from 120.69~323.92 mg·kg-1 and 183.69~418.21 mg·kg-1, respectively. The soil microbial biomass carbon basically showed a downward trend before growing season began and an upward trend with growing season end

  16. How light, temperature, and measurement and growth [CO2] interactively control isoprene emission in hybrid aspen.

    Science.gov (United States)

    Niinemets, Ülo; Sun, Zhihong

    2015-02-01

    Plant isoprene emissions have been modelled assuming independent controls by light, temperature and atmospheric [CO2]. However, the isoprene emission rate is ultimately controlled by the pool size of its immediate substrate, dimethylallyl diphosphate (DMADP), and isoprene synthase activity, implying that the environmental controls might interact. In addition, acclimation to growth [CO2] can shift the share of the control by DMADP pool size and isoprene synthase activity, and thereby alter the environmental sensitivity. Environmental controls of isoprene emission were studied in hybrid aspen (Populus tremula × Populus tremuloides) saplings acclimated either to ambient [CO2] of 380 μmol mol(-1) or elevated [CO2] of 780 μmol mol(-1). The data demonstrated strong interactive effects of environmental drivers and growth [CO2] on isoprene emissions. Light enhancement of isoprene emission was the greatest at intermediate temperatures and was greater in elevated-[CO2]-grown plants, indicating greater enhancement of the DMADP supply. The optimum temperature for isoprene emission was higher at lower light, suggesting activation of alternative DMADP sinks at higher light. In addition, [CO2] inhibition of isoprene emission was lost at a higher temperature with particularly strong effects in elevated-[CO2]-grown plants. Nevertheless, DMADP pool size was still predicted to more strongly control isoprene emission at higher temperatures in elevated-[CO2]-grown plants. We argue that interactive environmental controls and acclimation to growth [CO2] should be incorporated in future isoprene emission models at the level of DMADP pool size.

  17. 雾灵山自然保护区的山杨林%ASPEN (Populus davidiana) FOREST IN WULING   MOUNTAIN NATURAL RESERVE

    Institute of Scientific and Technical Information of China (English)

    郭文增

    2001-01-01

    The researches on Populus davidiana forest were carried out in Wuling Mountain Natural Reserve. It expounded its distribution, habitat, physiognomy character (biological spectrum, leaf-size class, leaf-tepe, leaf-margin), structural feature(synusia, vertical stratification, quantitative character), and predicated on the succession dynamic status of Populus davidiana forest was put forward.%对雾灵山自然保护区的山杨林进行了研究。详细论述了其分布、生境、种类组成、外貌特征(生活型谱、叶级、叶形、叶缘)、结构特征(层次、层片、综合数量特征),并对其演替动态进行了分析。

  18. Characterization of SP1, a Stress-Responsive, Boiling-Soluble, Homo-Oligomeric Protein from Aspen1

    Science.gov (United States)

    Wang, Wang-Xia; Pelah, Dan; Alergand, Tal; Shoseyov, Oded; Altman, Arie

    2002-01-01

    sp1 cDNA was isolated from aspen (Populus tremula) plants by immunoscreening an expression library using polyclonal antibodies against BspA protein. BspA, which is a boiling-stable protein, accumulates in aspen plants in response to water stress and abscisic acid application (Pelah et al., 1995). The sp1 cDNA was found to encode a 12.4-kD generally hydrophilic protein with a hydrophobic C terminus, which is different from the BspA protein and was termed SP1 (stable protein 1). Northern-blot analysis revealed that sp1 encodes a small mRNA (about 0.6 kb) that is expressed in aspen plants under non-stress conditions and is accumulated after salt, cold, heat, and desiccation stress, and during the recovery from stress. The SP1 detected in plants remained soluble upon boiling, migrated both as a 12.4-kD band and a much higher mass of 116 kD on a 17% (w/v) Tricine-sodium dodecyl sulfate-polyacrylamide gel. Comparative protease digestion patterns, amino acid analyses, and the N-terminal sequences of the 12.4- and 116-kD proteins revealed that SP1 is homo-oligomeric. Furthermore, gel filtration chromatography analysis indicated that SP1 exists in aspen plants as a complex, composed of 12 subunits of 12.4 kD. A large number of sequences deduced from expressed sequence tags and genomic sequences of other organisms with unknown function show high homology to SP1. Thus, SP1 may represent a new protein family. Here, we present the first report on this putative protein family: the cloning, isolation, and characterization of SP1, a stress-responsive, boiling-soluble, oligomeric protein. PMID:12376651

  19. Aspen Delineation - Aspen Delineation Project [ds362

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands, where aspen assessment data was gathered. Aspen assessment information corresponding to this polygon layer can...

  20. ИССЛЕДОВАНИЕ ФЕНОЛЬНЫХ СОЕДИНЕНИЙ И ЭЛЕМЕНТНОГО СОСТАВА КОРЫ POPULUS TREMULA L

    OpenAIRE

    МАРТЫНОВ АЛЬБЕРТ МИХАЙЛОВИЧ; ЧУПАРИНА ЕЛЕНА ВЛАДИМИРОВНА

    2015-01-01

    Изучены фенольные соединения и элементный состав коры осины ( Populus tremula L.) методом ВЭЖХ идентифицированы: гликозид - салицин; фенолкарбоновые кислоты: галловая, цикориевая, неохлорогеновая, коричная; флавоноиды: гесперидин, гиперозид, лютеолин-7-гликозид, рутин, дигидрокверцетин, кверцетин; а также эпикатехин, эпигаллокатехингаллат, установлено их количественное соотношение. Преобладающими являются салицин, коричная кислота, рутин и гиперозид. Методом рентгенофлуоресцентного анализа оп...

  1. Detection of Aspens Using High Resolution Aerial Laser Scanning Data and Digital Aerial Images

    Directory of Open Access Journals (Sweden)

    Kalle Eerikäinen

    2008-08-01

    Full Text Available The aim was to use high resolution Aerial Laser Scanning (ALS data and aerial images to detect European aspen (Populus tremula L. from among other deciduous trees. The field data consisted of 14 sample plots of 30 m × 30 m size located in the Koli National Park in the North Karelia, Eastern Finland. A Canopy Height Model (CHM was interpolated from the ALS data with a pulse density of 3.86/m2, low-pass filtered using Height-Based Filtering (HBF and binarized to create the mask needed to separate the ground pixels from the canopy pixels within individual areas. Watershed segmentation was applied to the low-pass filtered CHM in order to create preliminary canopy segments, from which the non-canopy elements were extracted to obtain the final canopy segmentation, i.e. the ground mask was analysed against the canopy mask. A manual classification of aerial images was employed to separate the canopy segments of deciduous trees from those of coniferous trees. Finally, linear discriminant analysis was applied to the correctly classified canopy segments of deciduous trees to classify them into segments belonging to aspen and those belonging to other deciduous trees. The independent variables used in the classification were obtained from the first pulse ALS point data. The accuracy of discrimination between aspen and other deciduous trees was 78.6%. The independent variables in the classification function were the proportion of vegetation hits, the standard deviation of in pulse heights, accumulated intensity at the 90th percentile and the proportion of laser points reflected at the 60th height percentile. The accuracy of classification corresponded to the validation results of earlier ALS-based studies on the classification of individual deciduous trees to tree species.

  2. Aspen Tension Wood Fibers Contain β-(1---> 4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in Gelatinous Walls.

    Science.gov (United States)

    Gorshkova, Tatyana; Mokshina, Natalia; Chernova, Tatyana; Ibragimova, Nadezhda; Salnikov, Vadim; Mikshina, Polina; Tryfona, Theodora; Banasiak, Alicja; Immerzeel, Peter; Dupree, Paul; Mellerowicz, Ewa J

    2015-11-01

    Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula × Populus tremuloides). β-(1→4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. β-(1→4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl)glucuronic acid and galactose in tension wood than in normal wood. Thus, β-(1→4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high β-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.

  3. Trade-offs between xylem hydraulic properties, wood anatomy and yield in Populus.

    Science.gov (United States)

    Hajek, Peter; Leuschner, Christoph; Hertel, Dietrich; Delzon, Sylvain; Schuldt, Bernhard

    2014-07-01

    Trees face the dilemma that achieving high plant productivity is accompanied by a risk of drought-induced hydraulic failure due to a trade-off in the trees' vascular system between hydraulic efficiency and safety. By investigating the xylem anatomy of branches and coarse roots, and measuring branch axial hydraulic conductivity and vulnerability to cavitation in 4-year-old field-grown aspen plants of five demes (Populus tremula L. and Populus tremuloides Michx.) differing in growth rate, we tested the hypotheses that (i) demes differ in wood anatomical and hydraulic properties, (ii) hydraulic efficiency and safety are related to xylem anatomical traits, and (iii) aboveground productivity and hydraulic efficiency are negatively correlated to cavitation resistance. Significant deme differences existed in seven of the nine investigated branch-related anatomical and hydraulic traits but only in one of the four coarse-root-related anatomical traits; this likely is a consequence of high intra-plant variation in root morphology and the occurrence of a few 'high-conductivity roots'. Growth rate was positively related to branch hydraulic efficiency (xylem-specific conductivity) but not to cavitation resistance; this indicates that no marked trade-off exists between cavitation resistance and growth. Both branch hydraulic safety and hydraulic efficiency significantly depended on vessel size and were related to the genetic distance between the demes, while the xylem pressure causing 88% loss of hydraulic conductivity (P88 value) was more closely related to hydraulic efficiency than the commonly used P50 value. Deme-specific variation in the pit membrane structure may explain why vessel size was not directly linked to growth rate. We conclude that branch hydraulic efficiency is an important growth-influencing trait in aspen, while the assumed trade-off between productivity and hydraulic safety is weak.

  4. ptr-MIR169 is a posttranscriptional repressor of PtrHAP2 during vegetative bud dormancy period of aspen (Populus tremuloides) trees

    Energy Technology Data Exchange (ETDEWEB)

    Potkar, Rewati; Recla, Jill [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States); Busov, Victor, E-mail: vbusov@mtu.edu [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)

    2013-02-15

    Highlights: ► We show a novel microRNA-mediated mechanism for control of bud dormancy in trees. ► ptr-MIR169a and PtrHAP2–5 gene showed inverse expression during dormancy period. ► The PtrHAP2–5 decline in abundance correlated with high ptr-MIR169a levels. ► PtrHAP2–5 cleavage occurred at the miR169 site during PtrHAP2–5 transcript decline. ► Our results show that miR169 attenuates PtrHAP2–5 transcript during dormancy. -- Abstract: Dormancy is a mechanism evolved in woody perennial plants to survive the winter freezing and dehydration stress via temporary suspension of growth. We have identified two aspen microRNAs (ptr-MIR169a and ptr-MIR169h) which were highly and specifically expressed in dormant floral and vegetative buds. ptr-MIR169a and its target gene PtrHAP2–5 showed inverse expression patterns during the dormancy period. ptr-MIR169a transcript steadily increased through the first half of the dormancy period and gradually declined with the approach of active growing season. PtrHAP2–5 abundance was higher in the beginning of the dormancy period but rapidly declined thereafter. The decline of PtrHAP2–5 correlated with the high levels of ptr-MIR169a accumulation, suggesting miR169-mediated attenuation of the target PtrHAP2–5 transcript. We experimentally verified the cleavage of PtrHAP2–5 at the predicted miR169a site at the time when PtrHAP2–5 transcript decline was observed. HAP2 is a subunit of a nuclear transcription factor Y (NF-Y) complex consisting of two other units, HAP3 and HAP5. Using digital expression profiling we show that poplar HAP2 and HAP5 are preferentially detected in dormant tissues. Our study shows that microRNAs play a significant and as of yet unknown and unstudied role in regulating the timing of bud dormancy in trees.

  5. Analyses of GA20ox- and GID1-over-expressing aspen suggest that gibberellins play two distinct roles in wood formation.

    Science.gov (United States)

    Mauriat, Mélanie; Moritz, Thomas

    2009-06-01

    Gibberellins (GAs) are involved in many aspects of plant development, including shoot growth, flowering and wood formation. Increased levels of bioactive GAs are known to induce xylogenesis and xylem fiber elongation in aspen. However, there is currently little information on the response pathway(s) that mediate GA effects on wood formation. Here we characterize an important element of the GA pathway in hybrid aspen: the GA receptor, GID1. Four orthologs of GID1 were identified in Populus tremula x P. tremuloides (PttGID1.1-1.4). These were functional when expressed in Arabidopsis thaliana, and appear to present a degree of sub-functionalization in hybrid aspen. PttGID1.1 and PttGID1.3 were over-expressed in independent lines of hybrid aspen using either the 35S promoter or a xylem-specific promoter (LMX5). The 35S:PttGID1 over-expressors shared several phenotypic traits previously described in 35S:AtGA20ox1 over-expressors, including rapid growth, increased elongation, and increased xylogenesis. However, their xylem fibers were not elongated, unlike those of 35S:AtGA20ox1 plants. Similar differences in the xylem fiber phenotype were observed when PttGID1.1, PttGID1.3 or AtGA20ox1 were expressed under the control of the LMX5 promoter, suggesting either that PttGID1.1 and PttGID1.3 play no role in fiber elongation or that GA homeostasis is strongly controlled when GA signaling is altered. Our data suggest that GAs are required in two distinct wood-formation processes that have tissue-specific signaling pathways: xylogenesis, as mediated by GA signaling in the cambium, and fiber elongation in the developing xylem.

  6. 13C Tracking after 13CO2 Supply Revealed Diurnal Patterns of Wood Formation in Aspen.

    Science.gov (United States)

    Mahboubi, Amir; Linden, Pernilla; Hedenström, Mattias; Moritz, Thomas; Niittylä, Totte

    2015-06-01

    Wood of trees is formed from carbon assimilated in the photosynthetic tissues. Determining the temporal dynamics of carbon assimilation, subsequent transport into developing wood, and incorporation to cell walls would further our understanding of wood formation in particular and tree growth in general. To investigate these questions, we designed a (13)CO2 labeling system to study carbon transport and incorporation to developing wood of hybrid aspen (Populus tremula × tremuloides). Tracking of (13)C incorporation to wood over a time course using nuclear magnetic resonance spectroscopy revealed diurnal patterns in wood cell wall biosynthesis. The dark period had a differential effect on (13)C incorporation to lignin and cell wall carbohydrates. No (13)C was incorporated into aromatic amino acids of cell wall proteins in the dark, suggesting that cell wall protein biosynthesis ceased during the night. The results show previously unrecognized temporal patterns in wood cell wall biosynthesis, suggest diurnal cycle as a possible cue in the regulation of carbon incorporation to wood, and establish a unique (13)C labeling method for the analysis of wood formation and secondary growth in trees.

  7. Evolution, three-dimensional model and localization of truncated hemoglobin PttTrHb of hybrid aspen.

    Science.gov (United States)

    Dumont, Estelle; Jokipii-Lukkari, Soile; Parkash, Vimal; Vuosku, Jaana; Sundström, Robin; Nymalm, Yvonne; Sutela, Suvi; Taskinen, Katariina; Kallio, Pauli T; Salminen, Tiina A; Häggman, Hely

    2014-01-01

    Thus far, research on plant hemoglobins (Hbs) has mainly concentrated on symbiotic and non-symbiotic Hbs, and information on truncated Hbs (TrHbs) is scarce. The aim of this study was to examine the origin, structure and localization of the truncated Hb (PttTrHb) of hybrid aspen (Populus tremula L. × tremuloides Michx.), the model system of tree biology. Additionally, we studied the PttTrHb expression in relation to non-symbiotic class1 Hb gene (PttHb1) using RNAi-silenced hybrid aspen lines. Both the phylogenetic analysis and the three-dimensional (3D) model of PttTrHb supported the view that plant TrHbs evolved vertically from a bacterial TrHb. The 3D model suggested that PttTrHb adopts a 2-on-2 sandwich of α-helices and has a Bacillus subtilis -like ligand-binding pocket in which E11Gln and B10Tyr form hydrogen bonds to a ligand. However, due to differences in tunnel cavity and gate residue (E7Ala), it might not show similar ligand-binding kinetics as in Bs-HbO (E7Thr). The immunolocalization showed that PttTrHb protein was present in roots, stems as well as leaves of in vitro -grown hybrid aspens. In mature organs, PttTrHb was predominantly found in the vascular bundles and specifically at the site of lateral root formation, overlapping consistently with areas of nitric oxide (NO) production in plants. Furthermore, the NO donor sodium nitroprusside treatment increased the amount of PttTrHb in stems. The observed PttTrHb localization suggests that PttTrHb plays a role in the NO metabolism.

  8. The effect of warming and enhanced ultraviolet radiation on gender-specific emissions of volatile organic compounds from European aspen

    Energy Technology Data Exchange (ETDEWEB)

    Maja, Mengistu M., E-mail: mengistu.maja@uef.fi [University of Eastern Finland, Department of Environmental Science, P.O.Box 1627, 70211 Kuopio (Finland); Kasurinen, Anne; Holopainen, Toini [University of Eastern Finland, Department of Environmental Science, P.O.Box 1627, 70211 Kuopio (Finland); Julkunen-Tiitto, Riitta [University of Eastern Finland, Department of Biology, P.O. Box 111, 80101 Joensuu (Finland); Holopainen, Jarmo K. [University of Eastern Finland, Department of Environmental Science, P.O.Box 1627, 70211 Kuopio (Finland)

    2016-03-15

    Different environmental stress factors often occur together but their combined effects on plant secondary metabolism are seldom considered. We studied the effect of enhanced ultraviolet (UV-B) (31% increase) radiation and temperature (ambient + 2 °C) singly and in combination on gender-specific emissions of volatile organic compounds (VOCs) from 2-year-old clones of European aspen (Populus tremula L.). Plants grew in 36 experimental plots (6 replicates for Control, UV-A, UV-B, T, UV-A + T and UV-B + T treatments), in an experimental field. VOCs emitted from shoots were sampled from two (1 male and 1 female) randomly selected saplings (total of 72 saplings), per plot on two sampling occasions (June and July) in 2014. There was a significant UV-B × temperature interaction effect on emission rates of different VOCs. Isoprene emission rate was increased due to warming, but warming also modified VOC responses to both UV-A and UV-B radiation. Thus, UV-A increased isoprene emissions without warming, whereas UV-B increased emissions only in combination with warming. Warming-modified UV-A and UV-B responses were also seen in monoterpenes (MTs), sesquiterpenes (SQTs) and green leaf volatiles (GLVs). MTs showed also a UV × gender interaction effect as females had higher emission rates under UV-A and UV-B than males. UV × gender and T × gender interactions caused significant differences in VOC blend as there was more variation (more GLVs and trans-β-caryophyllene) in VOCs from female saplings compared to male saplings. VOCs from the rhizosphere were also collected from each plot in two exposure seasons, but no significant treatment effects were observed. Our results suggest that simultaneous warming and elevated-UV-radiation increase the emission of VOCs from aspen. Thus the contribution of combined environmental factors on VOC emissions may have a greater impact to the photochemical reactions in the atmosphere compared to the impact of individual factors acting alone

  9. Aspen Trees.

    Science.gov (United States)

    Canfield, Elaine

    2002-01-01

    Describes a fifth-grade art activity that offers a new approach to creating pictures of Aspen trees. Explains that the students learned about art concepts, such as line and balance, in this lesson. Discusses the process in detail for creating the pictures. (CMK)

  10. Fire regimes of quaking aspen in the Mountain West

    Science.gov (United States)

    Shinneman, Douglas J.; Baker, William L.; Rogers, Paul C.; Kulakowski, Dominik

    2013-01-01

    Quaking aspen (Populus tremuloides Michx.) is the most widespread tree species in North America, and it is found throughout much of the Mountain West (MW) across a broad range of bioclimatic regions. Aspen typically regenerates asexually and prolifically after fire, and due to its seral status in many western conifer forests, aspen is often considered dependent upon disturbance for persistence. In many landscapes, historical evidence for post-fire aspen establishment is clear, and following extended fire-free periods senescing or declining aspen overstories sometimes lack adequate regeneration and are succeeding to conifers. However, aspen also forms relatively stable stands that contain little or no evidence of historical fire. In fact, aspen woodlands range from highly fire-dependent, seral communities to relatively stable, self-replacing, non-seral communities that do not require fire for persistence. Given the broad geographic distribution of aspen, fire regimes in these forests likely co-vary spatially with changing community composition, landscape setting, and climate, and temporally with land use and climate – but relatively few studies have explicitly focused on these important spatiotemporal variations. Here we reviewed the literature to summarize aspen fire regimes in the western US and highlight knowledge gaps. We found that only about one-fourth of the 46 research papers assessed for this review could be considered fire history studies (in which mean fire intervals were calculated), and all but one of these were based primarily on data from fire-scarred conifers. Nearly half of the studies reported at least some evidence of persistent aspen in the absence of fire. We also found that large portions of the MW have had little or no aspen fire history research. As a result of this review, we put forth a classification framework for aspen that is defined by key fire regime parameters (fire severity and probability), and that reflects underlying biophysical

  11. Controls of the quantum yield and saturation light of isoprene emission in different-aged aspen leaves.

    Science.gov (United States)

    Niinemets, Ülo; Sun, Zhihong; Talts, Eero

    2015-12-01

    Leaf age alters the balance between the use of end-product of plastidic isoprenoid synthesis pathway, dimethylallyl diphosphate (DMADP), in prenyltransferase reactions leading to synthesis of pigments of photosynthetic machinery and in isoprene synthesis, but the implications of such changes on environmental responses of isoprene emission have not been studied. Because under light-limited conditions, isoprene emission rate is controlled by DMADP pool size (SDMADP ), shifts in the share of different processes are expected to particularly strongly alter the light dependency of isoprene emission. We examined light responses of isoprene emission in young fully expanded, mature and old non-senescent leaves of hybrid aspen (Populus tremula x P. tremuloides) and estimated in vivo SDMADP and isoprene synthase activity from post-illumination isoprene release. Isoprene emission capacity was 1.5-fold larger in mature than in young and old leaves. The initial quantum yield of isoprene emission (αI ) increased by 2.5-fold with increasing leaf age primarily as the result of increasing SDMADP . The saturating light intensity (QI90 ) decreased by 2.3-fold with increasing leaf age, and this mainly reflected limited light-dependent increase of SDMADP possibly due to feedback inhibition by DMADP. These major age-dependent changes in the shape of the light response need consideration in modelling canopy isoprene emission.

  12. Defense Responses in Aspen with Altered Pectin Methylesterase Activity Reveal the Hormonal Inducers of Tyloses1[OPEN

    Science.gov (United States)

    Leśniewska, Joanna; Krzesłowska, Magdalena; Kushwah, Sunita; Sundberg, Björn; Moritz, Thomas

    2017-01-01

    Tyloses are ingrowths of parenchyma cells into the lumen of embolized xylem vessels, thereby protecting the remaining xylem from pathogens. They are found in heartwood, sapwood, and in abscission zones and can be induced by various stresses, but their molecular triggers are unknown. Here, we report that down-regulation of PECTIN METHYLESTERASE1 (PtxtPME1) in aspen (Populus tremula × tremuloides) triggers the formation of tyloses and activation of oxidative stress. We tested whether any of the oxidative stress-related hormones could induce tyloses in intact plantlets grown in sterile culture. Jasmonates, including jasmonic acid (JA) and methyl jasmonate, induced the formation of tyloses, whereas treatments with salicylic acid (SA) and 1-aminocyclopropane-1-carboxylic acid (ACC) were ineffective. SA abolished the induction of tyloses by JA, whereas ACC was synergistic with JA. The ability of ACC to stimulate tyloses formation when combined with JA depended on ethylene (ET) signaling, as shown by a decrease in the response in ET-insensitive plants. Measurements of internal ACC and JA concentrations in wild-type and ET-insensitive plants treated simultaneously with these two compounds indicated that ACC and JA regulate each other’s concentration in an ET-dependent manner. The findings indicate that jasmonates acting synergistically with ethylene are the key molecular triggers of tyloses. PMID:27923986

  13. Bisphosphonate inhibitors reveal a large elasticity of plastidic isoprenoid synthesis pathway in isoprene-emitting hybrid aspen.

    Science.gov (United States)

    Rasulov, Bahtijor; Talts, Eero; Kännaste, Astrid; Niinemets, Ülo

    2015-06-01

    Recently, a feedback inhibition of the chloroplastic 1-deoxy-D-xylulose 5-phosphate (DXP)/2-C-methyl-D-erythritol 4-phosphate (MEP) pathway of isoprenoid synthesis by end products dimethylallyl diphosphate (DMADP) and isopentenyl diphosphate (IDP) was postulated, but the extent to which DMADP and IDP can build up is not known. We used bisphosphonate inhibitors, alendronate and zoledronate, that inhibit the consumption of DMADP and IDP by prenyltransferases to gain insight into the extent of end product accumulation and possible feedback inhibition in isoprene-emitting hybrid aspen (Populus tremula × Populus tremuloides). A kinetic method based on dark release of isoprene emission at the expense of substrate pools accumulated in light was used to estimate the in vivo pool sizes of DMADP and upstream metabolites. Feeding with fosmidomycin, an inhibitor of DXP reductoisomerase, alone or in combination with bisphosphonates was used to inhibit carbon input into DXP/MEP pathway or both input and output. We observed a major increase in pathway intermediates, 3- to 4-fold, upstream of DMADP in bisphosphonate-inhibited leaves, but the DMADP pool was enhanced much less, 1.3- to 1.5-fold. In combined fosmidomycin/bisphosphonate treatment, pathway intermediates accumulated, reflecting cytosolic flux of intermediates that can be important under strong metabolic pull in physiological conditions. The data suggested that metabolites accumulated upstream of DMADP consist of phosphorylated intermediates and IDP. Slow conversion of the huge pools of intermediates to DMADP was limited by reductive energy supply. These data indicate that the DXP/MEP pathway is extremely elastic, and the presence of a significant pool of phosphorylated intermediates provides an important valve for fine tuning the pathway flux.

  14. Polyploidy in aspen alters plant physiology and drought sensitivity

    Science.gov (United States)

    Greer, B.; Still, C. J.; Brooks, J. R.; Meinzer, F. C.

    2015-12-01

    Polyploids of quaking aspen (Populus tremuloides) may be better suited to dry climatic conditions than diploids. However, the expression of diploid and polyploid functional traits, including water use efficiency, an important component of drought avoidance and tolerance, are not well understood in quaking aspen. In this study diploid and triploid aspen clones' leaf, ramet, and stand functional traits were measured near the Rocky Mountain Biological Laboratory in Gothic, Colorado. The physiology of diploid and triploid aspen, including leaf size, chlorophyll content, stomatal size and density and stomatal conductance, as well as growth rates and carbon isotope discrimination in response to climate (measured in tree rings), were found to be significantly different between ploidy levels. These findings demonstrate different sensitivities of diploid and triploid clones to drought related climate stressors which may impact strategies for aspen forest management and conservation.

  15. Interactive effects of supplemental UV-B and temperature in European aspen seedlings: Implications for growth, leaf traits, phenolic defense and associated organisms.

    Science.gov (United States)

    Randriamanana, Tendry R; Lavola, Anu; Julkunen-Tiitto, Riitta

    2015-08-01

    Past studies reveal opposite effects of elevated UV-B and temperature on plant growth and concentrations of UV-B absorbing compounds, yet few studies have dealt with the combined and interactive effects of these two climate change factors on woody dioecious plants. We investigated the interactive effects of UV-B and temperature treatments on growth, leaf traits and phenolic concentrations in Populus tremula L. (European aspen) seedlings. We also considered the consequences of these effects on their associated organisms: herbivorous insects, rust pathogens, the presence of endophytic fungi and whether or not the responses differ between genders and genotypes. Supplemental temperature and UV-B were modulated to +2 °C and +30.77% above ambient conditions, respectively. Warming increased growth, photosynthesis and foliar nitrogen concentration but reduced leaf thickness and phenolic concentrations. On the other hand, supplemental UV-B increased total phenolic glycosides, mainly flavonols and phenolic acids, and partially counteracted the positive effects of warming on growth. Fast growing genotypes were less susceptible to the growth-reducing effect of combined UVB + T, less infected with rust disease and less prone to insect damage probably due to their higher salicylate and lower nitrogen concentrations. Under ambient temperature, the males of European aspen were taller and had bigger leaves than the females, while under elevated temperature, females grew bigger and, under UV-B, had more tremulacin than males. The multiple interactive effects of UV-B and temperature on growth, leaf traits and phenolic compounds, highlight the importance of multifactor experiments as a realistic predictor of plant responses to climate change.

  16. Aspen Characteristics - Aspen Delineation Project [ds361

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands in the Lake Tahoe Basin Management Unit (Placer and...

  17. Quantifying the consequences of conifer succession in aspen stands: decline in a biodiversity-supporting community.

    Science.gov (United States)

    McCullough, S A; O'Geen, A T; Whiting, M L; Sarr, D A; Tate, K W

    2013-07-01

    Quaking aspen (Populus tremuloides Michaux) stands are important for biodiversity in conifer-dominated forest landscapes. Our goal was to quantify the consequences of conifer succession on understory diversity and litter quality, as well as associated changes in aspen stand condition. We studied aspen stands on national park land in the transition zone between the northern Sierra Nevada and southern Cascade mountain ranges. We field-measured ten metrics of aspen stand condition in 29 aspen stands. Along a gradient of increasing current conifer cover, we observed decreases in herbaceous species diversity and richness and an increase in forest floor O horizon depth. We interpreted aerial photos from 1952 and 1998 to determine whether directional changes in conifer cover had occurred in the stands over the past half century, and used regression modeling to associate succession with the observed range of aspen stand condition. From the period 1952 to 1998, we found that conifer encroachment occurred in half the sampled stands, with an average increase in conifer cover of 1% a year. Aspen were persistent in the remaining stands. Stand cover dynamics and percent total canopy cover interacted to influence species richness, diversity, aspen sprouting, and litter quality. In stands with conifer encroachment, both understory species richness and diversity declined. Although aspen sprouting increased, aspen establishment declined and the relative mass of woody to fine soil litter increased.

  18. Co-effect of increased humidity and meteorological conditions on greenhouse gas fluxes in a young hybrid aspen forest

    Science.gov (United States)

    Hansen, Raili; Mander, Ülo; Kupper, Priit; Soosaar, Kaido; Maddison, Martin; Sõber, Jaak; Lõhmus, Krista

    2014-05-01

    Due to the climate change, higher precipitation and an increase in air humidity is expected in northern Europe in the near future (IPCC 2007). There are some studies about irrigation, elevated CO2 and O3 etc., but still we have too little knowledge about the humidity effect on the deciduous forest ecosystem. In 2006 a free-air humidity manipulation (FAHM) facility was established in Estonia and in 2008 we started to artificially increase the air humidity in young hybrid aspen (Populus tremula L. x P. tremuloides Michx.) forest trials on an Endogleyic Planosol of former arable land. Air humidity was raised on average about 7% compared to ambient condition (Tullus et al., 2012). We measured the carbon dioxide, methane and nitrous oxide fluxes from the FAHM system using closed static chamber and gas-chromatograph techniques from July 2009 to November 2012 during snow free periods. Flux measurements were done once a month in three humidification (h) plots and in three control (c) plots. We monitored soil temperature, soil water potential (SWP), precipitation and relative humidity. The vegetation period was rainy in 2009, droughty in 2010 and 2011 (according to SWP the drought was severe in 2011) and cold in 2012. Soil respiration was the lowest in 2011 both in c and h plots; however it was significantly higher in h. Most of the time the soil was a sink for methane, but less CH4 was oxidized in the soil of h plots. Emission of N2O did not have good correlation with air humidity, although one could observe a clear tendency of bigger N2O fluxes when soil was continuously water-saturated. Expectedly, soil respiration had strong positive correlations with soil temperature and CH4 emission demonstrated strong positive correlation with SWP. Hence, interaction of humidification and precipitation affected greenhouse gas fluxes. IPCC, Climate Change 2007: The Physical Science Basis. Cambridge University Press, Cambridge. 2007. Tullus A, Kupper P, Sellin A, Parts L, Sõber J

  19. The effect of warming and enhanced ultraviolet radiation on gender-specific emissions of volatile organic compounds from European aspen.

    Science.gov (United States)

    Maja, Mengistu M; Kasurinen, Anne; Holopainen, Toini; Julkunen-Tiitto, Riitta; Holopainen, Jarmo K

    2016-03-15

    Different environmental stress factors often occur together but their combined effects on plant secondary metabolism are seldom considered. We studied the effect of enhanced ultraviolet (UV-B) (31% increase) radiation and temperature (ambient +2 °C) singly and in combination on gender-specific emissions of volatile organic compounds (VOCs) from 2-year-old clones of European aspen (Populus tremula L.). Plants grew in 36 experimental plots (6 replicates for Control, UV-A, UV-B, T, UV-A+T and UV-B+T treatments), in an experimental field. VOCs emitted from shoots were sampled from two (1 male and 1 female) randomly selected saplings (total of 72 saplings), per plot on two sampling occasions (June and July) in 2014. There was a significant UV-B×temperature interaction effect on emission rates of different VOCs. Isoprene emission rate was increased due to warming, but warming also modified VOC responses to both UV-A and UV-B radiation. Thus, UV-A increased isoprene emissions without warming, whereas UV-B increased emissions only in combination with warming. Warming-modified UV-A and UV-B responses were also seen in monoterpenes (MTs), sesquiterpenes (SQTs) and green leaf volatiles (GLVs). MTs showed also a UV × gender interaction effect as females had higher emission rates under UV-A and UV-B than males. UV × gender and T × gender interactions caused significant differences in VOC blend as there was more variation (more GLVs and trans-β-caryophyllene) in VOCs from female saplings compared to male saplings. VOCs from the rhizosphere were also collected from each plot in two exposure seasons, but no significant treatment effects were observed. Our results suggest that simultaneous warming and elevated-UV-radiation increase the emission of VOCs from aspen. Thus the contribution of combined environmental factors on VOC emissions may have a greater impact to the photochemical reactions in the atmosphere compared to the impact of individual factors acting alone.

  20. Comparative physiology of allopatric Populus species: geographic clines in photosynthesis, height growth, and carbon isotope discrimination in common gardens.

    Science.gov (United States)

    Soolanayakanahally, Raju Y; Guy, Robert D; Street, Nathaniel R; Robinson, Kathryn M; Silim, Salim N; Albrectsen, Benedicte R; Jansson, Stefan

    2015-01-01

    Populus species with wide geographic ranges display strong adaptation to local environments. We studied the clinal patterns in phenology and ecophysiology in allopatric Populus species adapted to similar environments on different continents under common garden settings. As a result of climatic adaptation, both Populus tremula L. and Populus balsamifera L. display latitudinal clines in photosynthetic rates (A), whereby high-latitude trees of P. tremula had higher A compared to low-latitude trees and nearly so in P. balsamifera (p = 0.06). Stomatal conductance (g s) and chlorophyll content index (CCI) follow similar latitudinal trends. However, foliar nitrogen was positively correlated with latitude in P. balsamifera and negatively correlated in P. tremula. No significant trends in carbon isotope composition of the leaf tissue (δ(13)C) were observed for both species; but, intrinsic water-use efficiency (WUEi) was negatively correlated with the latitude of origin in P. balsamifera. In spite of intrinsically higher A, high-latitude trees in both common gardens accomplished less height gain as a result of early bud set. Thus, shoot biomass was determined by height elongation duration (HED), which was well approximated by the number of days available for free growth between bud flush and bud set. We highlight the shortcoming of unreplicated outdoor common gardens for tree improvement and the crucial role of photoperiod in limiting height growth, further complicating interpretation of other secondary effects.

  1. Reconciling divergent interpretations of quaking aspen decline on the northern Colorado Front Range.

    Science.gov (United States)

    Kashian, Daniel M; Romme, William H; Regan, Claudia M

    2007-07-01

    Ecologists have debated over the past 65 years whether quaking aspen (Populus tremuloides Michx.) has or has not declined in abundance, vigor, or regeneration in western North America. Many studies have provided divergent interpretations of the condition of aspen forests, leading to difficulty in translating this ecological information into management recommendations. To reconcile these contrasting conclusions and to test the hypothesis that multiple types of aspen decline and persistence occur simultaneously on heterogeneous landscapes, we assessed 91 aspen stands across the northern Colorado Front Range to determine the range of ecological conditions that underlie aspen decline or persistence. Approximately 15% of aspen forest area in our sample exhibited dieback of mature stems coupled with a lack of young trees indicative of declining stands, most often at lower elevations where elk browsing is heavy and chronic, and where effects of fire exclusion have been most significant. However, 52% of the area sampled had multiple cohorts indicative of self-replacing or persistent stands. Conifer dominance was increasing in over 33% of all aspen forest area sampled, most often at high elevations among lodgepole pine (Pinus contorta var. latifolia Englem. ex Wats.) forests. Reconstructions of relative basal area and density of aspen and lodgepole pine in these stands suggest cyclical dominance of these species, where conifers gradually replace aspen over long fire intervals, and aspen vigorously re-establish following stand-replacing fires. The diversity of ecological contexts across the northern Colorado Front Range creates a variety of aspen dynamics leading to decline or persistence, and no single trend describes the general condition of aspen forests in appropriate detail for managers. Active management may be useful in preserving individual stands at fine scales, but management prescriptions should reflect specific drivers of decline in these stands.

  2. Recovering aspen follow changing elk dynamics in Yellowstone: evidence of a trophic cascade?

    Science.gov (United States)

    Painter, Luke E; Beschta, Robert L; Larsen, Eric J; Ripple, William J

    2015-01-01

    To investigate the extent and causes of recent quaking aspen (Populus tremuloides) recruitment in northern Yellowstone National Park, we measured browsing intensity and height of young aspen in 87 randomly selected aspen stands in 2012, and compared our results to similar data collected in 1997-1998. We also examined the relationship between aspen recovery and the distribution of Rocky Mountain elk (Cervus elaphus) and bison (Bison bison) on the Yellowstone northern ungulate winter range, using ungulate fecal pile densities and annual elk count data. In 1998, 90% of young aspen were browsed and none were taller-than 200 cm, the height at which aspen begin to escape from elk browsing. In 2012, only 37% in the east and 63% in the west portions of the winter range were browsed, and 65% of stands in the east had young aspen taller than 200 cm. Heights of young aspen were inversely related to browsing intensity, with the least browsing and greatest heights in the eastern portion of the range, corresponding with recent changes in elk density and distribution. In contrast with historical elk distribution (1930s-1990s), the greatest densities of elk recently (2006-2012) have been north of the park boundary (approximately 5 elk/km2), and in the western part of the range (2-4 elk/km2), with relatively few elk in the eastern portion of the range (aspen stands have begun to recover. Increased predation pressure following the reintroduction of gray wolves (Canis lupius) in 1995-1996 played a role in these changing elk population dynamics, interacting with other influences including increased predation by bears (Ursus spp.), competition with an expanding bison population, and shifting patterns of human land use and hunting outside the park. The resulting new aspen recruitment is evidence of a landscape-scale trophic cascade in which a resurgent large carnivore community, combined with other ecological changes, has benefited aspen through effects on ungulate prey.

  3. Drought characteristics' role in widespread aspen forest mortality across Colorado, USA.

    Science.gov (United States)

    Anderegg, Leander D L; Anderegg, William R L; Abatzoglou, John; Hausladen, Alexandra M; Berry, Joseph A

    2013-05-01

    Globally documented widespread drought-induced forest mortality has important ramifications for plant community structure, ecosystem function, and the ecosystem services provided by forests. Yet the characteristics of drought seasonality, severity, and duration that trigger mortality events have received little attention despite evidence of changing precipitation regimes, shifting snow melt timing, and increasing temperature stress. This study draws upon stand level ecohydrology and statewide climate and spatial analysis to examine the drought characteristics implicated in the recent widespread mortality of trembling aspen (Populus tremuloides Michx.). We used isotopic observations of aspen xylem sap to determine water source use during natural and experimental drought in a region that experienced high tree mortality. We then drew upon multiple sources of climate data to characterize the drought that triggered aspen mortality. Finally, regression analysis was used to examine the drought characteristics most associated with the spatial patterns of aspen mortality across Colorado. Isotopic analysis indicated that aspens generally utilize shallow soil moisture with little plasticity during drought stress. Climate analysis showed that the mortality-inciting drought was unprecedented in the observational record, especially in 2002 growing season temperature and evaporative deficit, resulting in record low shallow soil moisture reserves. High 2002 summer temperature and low shallow soil moisture were most associated with the spatial patterns of aspen mortality. These results suggest that the 2002 drought subjected Colorado aspens to the most extreme growing season water stress of the past century by creating high atmospheric moisture demand and depleting the shallow soil moisture upon which aspens rely. Our findings highlight the important role of drought characteristics in mediating widespread aspen forest mortality, link this aspen die-off to regional climate change

  4. From the Aspen File.

    Science.gov (United States)

    Aspen Institute Quarterly, 1993

    1993-01-01

    Presents nine recommendations developed at the 1992 Policy Issue Forum of the Aspen Institute's Program on Policy Issues in Energy and Resources. The underlying theme is that the world is entering a new era of environmental policy formation. Issues a call for a national strategy for environmental management. (SLD)

  5. Fluxes of CH4 and N2O in aspen stands grown under ambient and twice-ambient CO2

    DEFF Research Database (Denmark)

    Ambus, P.; Robertson, G.P.

    1999-01-01

    Elevated atmospheric CO2 has the potential to change below-ground nutrient cycling and thereby alter the soil-atmosphere exchange of biogenic trace gases. We measured fluxes of CH4 and N2O in trembling aspen (Populus tremuloides Michx.) stands grown in open-top chambers under ambient and twice...

  6. Aspen Ecology in Rocky Mountain National Park: Age Distribution, Genetics, and the Effects of Elk Herbivory

    Science.gov (United States)

    Zeigenfuss, Linda C.; Binkley, Dan; Tuskan, Gerald A.; Romme, William H.; Yin, Tongming; DiFazio, Stephen; Singer, Francis J.

    2008-01-01

    Lack of recruitment and canopy replacement of aspen (Populus tremuloides) stands that grow on the edges of grasslands on the low-elevation elk (Cervus elaphus) winter range of Rocky Mountain National Park (RMNP) in Colorado have been a cause of concern for more than 70 years. We used a combination of traditional dendrochronology and genetic techniques as well as measuring the characteristics of regenerating and nonregenerating stands on the elk winter range to determine when and under what conditions and estimated elk densities these stands established and through what mechanisms they may regenerate. The period from 1975 to 1995 at low elevation on the east side had 80-95 percent fewer aspen stems than would be expected based on the trend from 1855 through 1965. The age structure of aspen in the park indicates that the interacting effects of fires, elk population changes, and livestock grazing had more-or-less consistent effects on aspen from 1855 to 1965. The lack of a significant change in aspen numbers in recent decades in the higher elevation and west side parts of the park supports the idea that the extensive effects of elk browsing have been more important in reducing aspen numbers than other factors. The genetic variation of aspen populations in RMNP is high at the molecular level. We expected to find that most patches of aspen in the park were composed of a single clone of genetically identical trees, but in fact just 7 percent of measured aspen patches consisted of a single clone. A large frequency of polyploid (triploid and tetraploid) genotypes were found on the low elevation, east-side elk winter range. Nonregenerating aspen stands on the winter range had greater annual offtake, shorter saplings, and lower density of mid-height (1.5-2.5 m) saplings than regenerating stands. Overwinter elk browsing, however, did not appear to inhibit the leader length of aspen saplings. The winter range aspen stands of RMNP appear to be highly resilient in the face of

  7. The Impact of Nitrogen Limitation and Mycorrhizal Symbiosis on Aspen Tree Growth and Development

    Energy Technology Data Exchange (ETDEWEB)

    Tran, Bich Thi Ngoc [Univ. of Alabama, Huntsville, AL (United States)

    2014-08-18

    Nitrogen deficiency is the most common and widespread nutritional deficiency affecting plants worldwide. Ectromycorrhizal symbiosis involves the beneficial interaction of plants with soil fungi and plays a critical role in nutrient cycling, including the uptake of nitrogen from the environment. The main goal of this study is to understand how limiting nitrogen in the presence or absence of an ectomycorrhizal fungi, Laccaria bicolor, affects the health of aspen trees, Populus temuloides.

  8. Aspen Delineation - Klamath National Forest [ds370

    Data.gov (United States)

    California Department of Resources — The database represents polygons of aspen stands in the Klamath National Forest, Siskiyou County, California. The Klamath National Forest Region 5 Vegetation aspen...

  9. Aspen Delineation - Inyo National Forest [ds366

    Data.gov (United States)

    California Department of Resources — The database represents delineations of known aspen stands where aspen assessments were collected in the Inyo National Forest, Inyo County, California. The Inyo...

  10. THE ASPEN CONTINUOUS PROGRESS PLAN.

    Science.gov (United States)

    MORNINGSTAR, NED

    THIS REPORT IS A DOCUMENTATION OF THE EFFORTS OF THE STAFF OF THE ASPEN ELEMENTARY SCHOOL, ASPEN, COLORADO, TO INDIVIDUALIZE THE INSTRUCTIONAL PROGRAM IN GRADES K-6. INVOLVED IN THIS WERE APPROXIMATELY 450 STUDENTS AND A STAFF OF 13 TEACHERS. THE INDIVIDUALIZATION OF INSTRUCTION WAS ACCOMPLISHED THROUGH THE MODIFICATION OF THE TEACHING-LEARNING…

  11. Leaf and canopy conductance in aspen and aspen-birch forests under free-air enrichment of carbon dioxide and ozone.

    Science.gov (United States)

    Uddling, Johan; Teclaw, Ronald M; Pregitzer, Kurt S; Ellsworth, David S

    2009-11-01

    Increasing concentrations of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) have the potential to affect tree physiology and structure, and hence forest feedbacks on climate. Here, we investigated how elevated concentrations of CO2 (+45%) and O3 (+35%), alone and in combination, affected conductance for mass transfer at the leaf and canopy levels in pure aspen (Populus tremuloides Michx.) and in mixed aspen and birch (Betula papyrifera Marsh.) forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). The study was conducted during two growing seasons, when steady-state leaf area index (L) had been reached after > 6 years of exposure to CO2- and O3-enrichment treatments. Canopy conductance (g(c)) was estimated from stand sap flux, while leaf-level conductance of sun leaves in the upper canopy was derived by three different and independent methods: sap flux and L in combination with vertical canopy modelling, leaf 13C discrimination methodology in combination with photosynthesis modelling and leaf-level gas exchange. Regardless of the method used, the mean values of leaf-level conductance were higher in trees growing under elevated CO2 and/or O3 than in trees growing in control plots, causing a CO2 x O3 interaction that was statistically significant (P aspen and mixed aspen-birch communities. These results demonstrate that short-term primary stomatal closure responses to elevated CO2 and O3 were completely offset by long-term cumulative effects of these trace gases on tree and stand structure in determining canopy- and leaf-level conductance in pure aspen and mixed aspen-birch forests. Our results, together with the findings from other long-term FACE experiments with trees, suggest that model assumptions of large reductions in stomatal conductance under rising atmospheric CO2 are very uncertain for forests.

  12. The role of phytochrome A and gibberellins in growth under long and short day conditions: Studies in hybrid aspen

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, M.E. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology

    2000-07-01

    This thesis addresses questions concerning the regulation of growth and, specifically, the cessation of growth in response to short days in deciduous tree species. The model tree used in the studies was hybrid aspen (Populus tremula L. x P. tremuloides Michx.). We have exploited the possibility of transforming this species to modulate the level of expression of target genes using over-expression and antisense techniques. The target genes in the studies were the photoreceptor phytochrome A (phyA) and gibberellin 20-oxidase (GA 20-oxidase), the latter being a highly regulated enzyme involved in the biosynthesis of gibberellins (GAs). The photoreceptor phyA has been implicated in photoperiodic regulation of growth, while GAs may regulate the physiological response further downstream. The endogenous expression of these genes has been investigated in parallel with studies of various plants with ectopic and reduced levels of expression. The main focus has been on the early stages of induction of growth cessation and its physiological and molecular mechanisms. Studies of hybrid aspen plants with an increased or reduced expression of phyA, show this receptor to mediate the photoperiodic regulation of growth. Plants with ectopic expression could not stop growing despite drastically shortened photoperiods, while the antisense plants showed the reverse phenotype, with a higher sensitivity resulting in earlier cessation of growth. The role of GAs in growth inhibition was also addressed using plants with a reduction in GA levels. These plants showed early cessation of growth and dormancy, and thus an increased sensitivity toward daylength. Conversely, plants with increased rates of GA biosynthesis showed increased growth and stopped growing much later. Furthermore, increases in GA biosynthesis, resulting in high levels of GAs have a major impact on growth. Plants with high GA levels have increased elongation and diameter growth, due to higher rates of cell production in the

  13. Perturbation of wood cellulose synthesis causes pleiotropic effects in transgenic aspen.

    Science.gov (United States)

    Joshi, Chandrashekhar P; Thammannagowda, Shivegowda; Fujino, Takeshi; Gou, Ji-Qing; Avci, Utku; Haigler, Candace H; McDonnell, Lisa M; Mansfield, Shawn D; Mengesha, Bemnet; Carpita, Nicholas C; Harris, Darby; Debolt, Seth; Peter, Gary F

    2011-03-01

    Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility, the overexpression of an aspen secondary wall-associated cellulose synthase (PtdCesA8) gene was attempted in transgenic aspen (Populus tremuloides L.) and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing, and weak branches adopted a weeping growth habit. Furthermore, transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem (wood) of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin (35%) and non-cellulosic polysaccharides (55%) compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems produced typical collapsed or 'irregular' xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees.

  14. Perturbation of Wood Cellulose Synthesis Causes Pleiotropic Effects in Transgenic Aspen

    Institute of Scientific and Technical Information of China (English)

    Chandrashekhar P.Joshi; Nicholas C.Carpita; Darby Harris; Seth DeBolt; Gary F.Peter; Shivegowda Thammannagowda; Takeshi Fujino; Ji-Qing Gou; Utku Avci; Candace H.Haigler; Lisa M.McDonnell; Shawn D.Mansfield; Bemnet Mengesha

    2011-01-01

    Genetic manipulation of cellulose biosynthesis in trees may provide novel insights into the growth and development of trees. To explore this possibility,the overexpression of an aspen secondary wall-associated cellulose syn-thase (PtdCesA8) gene was attempted in transgenic aspen (Populus tremuloides L.) and unexpectedly resulted in silencing of the transgene as well as its endogenous counterparts. The main axis of the transgenic aspen plants quickly stopped growing,and weak branches adopted a weeping growth habit. Furthermore,transgenic plants initially developed smaller leaves and a less extensive root system. Secondary xylem (wood) of transgenic aspen plants contained as little as 10% cellulose normalized to dry weight compared to 41% cellulose typically found in normal aspen wood. This massive reduction in cellulose was accompanied by proportional increases in lignin (35%) and non-cellulosic polysaccharides (55%) compared to the 22% lignin and 36% non-cellulosic polysaccharides in control plants. The transgenic stems produced typical collapsed or 'irregular' xylem vessels that had altered secondary wall morphology and contained greatly reduced amounts of crystalline cellulose. These results demonstrate the fundamental role of secondary wall cellulose within the secondary xylem in maintaining the strength and structural integrity required to establish the vertical growth habit in trees.

  15. Aspen Ecology in Rocky Mountain National Park: Age Distribution, Genetics, and the Effects of Elk Herbivory

    Energy Technology Data Exchange (ETDEWEB)

    Tuskan, Gerald A [ORNL; Yin, Tongming [ORNL

    2008-10-01

    Lack of aspen (Populus tremuloides) recruitment and canopy replacement of aspen stands that grow on the edges of grasslands on the low-elevation elk (Cervus elaphus) winter range of Rocky Mountain National Park (RMNP) in Colorado has been a cause of concern for more than 70 years (Packard, 1942; Olmsted, 1979; Stevens, 1980; Hess, 1993; R.J. Monello, T.L. Johnson, and R.G. Wright, Rocky Mountain National Park, 2006, written commun.). These aspen stands are a significant resource since they are located close to the park's road system and thus are highly visible to park visitors. Aspen communities are integral to the ecological structure of montane and subalpine landscapes because they contain high native species richness of plants, birds, and butterflies (Chong and others, 2001; Simonson and others, 2001; Chong and Stohlgren, 2007). These low-elevation, winter range stands also represent a unique component of the park's plant community diversity since most (more than 95 percent) of the park's aspen stands grow in coniferous forest, often on sheltered slopes and at higher elevations, while these winter range stands are situated on the low-elevation ecotone between the winter range grasslands and some of the park's drier coniferous forests.

  16. Forest stand structure, productivity, and age mediate climatic effects on aspen decline.

    Science.gov (United States)

    Bell, David M; Bradford, John B; Lauenroth, William K

    2014-08-01

    Because forest stand structure, age, and productivity can mediate the impacts of climate on quaking aspen (Populus tremuloides) mortality, ignoring stand-scale factors limits inference on the drivers of recent sudden aspen decline. Using the proportion of aspen trees that were dead as an index of recent mortality at 841 forest inventory plots, we examined the relationship of this mortality index to forest structure and climate in the Rocky Mountains and Intermountain Western United States. We found that forest structure explained most of the patterns in mortality indices, but that variation in growing-season vapor pressure deficit and winter precipitation over the last 20 years was important. Mortality index sensitivity to precipitation was highest in forests where aspen exhibited high densities, relative basal areas, quadratic mean diameters, and productivities, whereas sensitivity to vapor pressure deficit was highest in young forest stands. These results indicate that the effects of drought on mortality may be mediated by forest stand development, competition with encroaching conifers, and physiological vulnerabilities of large trees to drought. By examining mortality index responses to both forest structure and climate, we show that forest succession cannot be ignored in studies attempting to understand the causes and consequences of sudden aspen decline.

  17. Alteration of PHYA expression change circadian rhythms and timing of bud set in Populus.

    Science.gov (United States)

    Kozarewa, Iwanka; Ibáñez, Cristian; Johansson, Mikael; Ogren, Erling; Mozley, David; Nylander, Eva; Chono, Makiko; Moritz, Thomas; Eriksson, Maria E

    2010-05-01

    In many temperate woody species, dormancy is induced by short photoperiods. Earlier studies have shown that the photoreceptor phytochrome A (phyA) promotes growth. Specifically, Populus plants that over-express the oat PHYA gene (oatPHYAox) show daylength-independent growth and do not become dormant. However, we show that oatPHYAox plants could be induced to set bud and become cold hardy by exposure to a shorter, non-24 h diurnal cycle that significantly alters the relative position between endogenous rhythms and perceived light/dark cycles. Furthermore, we describe studies in which the expression of endogenous Populus tremula x P. tremuloides PHYTOCHROME A (PttPHYA) was reduced in Populus trees by antisense inhibition. The antisense plants showed altered photoperiodic requirements, resulting in earlier growth cessation and bud formation in response to daylength shortening, an effect that was explained by an altered innate period that leads to phase changes of clock-associated genes such as PttCO2. Moreover, gene expression studies following far-red light pulses show a phyA-mediated repression of PttLHY1 and an induction of PttFKF1 and PttFT. We conclude that the level of PttPHYA expression strongly influences seasonally regulated growth in Populus and is central to co-ordination between internal clock-regulated rhythms and external light/dark cycles through its dual effect on the pace of clock rhythms and in light signaling.

  18. Taxonomy Icon Data: quaking aspen [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available png Populus_tremuloides_S.png Populus_tremuloides_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Po...pulus+tremuloides&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+tremuloides&t=NL http://biosciencedbc.jp/taxonomy..._icon/icon.cgi?i=Populus+tremuloides&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Populus+tremuloides&t=NS ...

  19. Are wolves saving Yellowstone's aspen? A landscape-level test of a behaviorally mediated trophic cascade.

    Science.gov (United States)

    Kauffman, Matthew J; Brodie, Jedediah F; Jules, Erik S

    2010-09-01

    Behaviorally mediated trophic cascades (BMTCs) occur when the fear of predation among herbivores enhances plant productivity. Based primarily on systems involving small-bodied predators, BMTCs have been proposed as both strong and ubiquitous in natural ecosystems. Recently, however, synthetic work has suggested that the existence of BMTCs may be mediated by predator hunting mode, whereby passive (sit-and-wait) predators have much stronger effects than active (coursing) predators. One BMTC that has been proposed for a wide-ranging active predator system involves the reintroduction of wolves (Canis lupus) to Yellowstone National Park, USA, which is thought to be leading to a recovery of trembling aspen (Populus tremuloides) by causing elk (Cervus elaphus) to avoid foraging in risky areas. Although this BMTC has been generally accepted and highly popularized, it has never been adequately tested. We assessed whether wolves influence aspen by obtaining detailed demographic data on aspen Stands using tree rings and by monitoring browsing levels in experimental elk exclosures arrayed across a gradient of predation risk for three years. Our study demonstrates that the historical failure of aspen to regenerate varied widely among stands (last recruitment year ranged from 1892 to 1956), and our data do not indicate an abrupt cessation of recruitment. This pattern of recruitment failure appears more consistent with a gradual increase in elk numbers rather than a rapid behavioral shift in elk foraging following wolf extirpation. In addition, our estimates of relative survivorship of young browsable aspen indicate that aspen are not currently recovering in Yellowstone, even in the presence of a large wolf population. Finally, in an experimental test of the BMTC hypothesis we found that the impacts of elk browsing on aspen demography are not diminished in sites where elk are at higher risk of predation by wolves. These findings suggest the need to further evaluate how trophic

  20. Drought-induced xylem pit membrane damage in aspen and balsam poplar.

    Science.gov (United States)

    Hillabrand, Rachel M; Hacke, Uwe G; Lieffers, Victor J

    2016-10-01

    Drought induces an increase in a tree's vulnerability to a loss of its hydraulic conductivity in many tree species, including two common in western Canada, trembling aspen (Populus tremuloides) and balsam poplar (Populus balsamifera). Termed 'cavitation fatigue' or 'air-seeding fatigue', the mechanism of this phenomenon is not well understood, but hypothesized to be a result of damage to xylem pit membranes. To examine the validity of this hypothesis, the effect of drought on the porosity of pit membranes in aspen and balsam poplar was investigated. Controlled drought and bench dehydration treatments were used to induce fatigue and scanning electron microscopy (SEM) was used to image pit membranes for relative porosity evaluations from air-dried samples after ethanol dehydration. A significant increase in the diameter of the largest pore was found in the drought and dehydration treatments of aspen, while an increase in the percentage of porous pit membranes was found in the dehydration treatments of both species. Additionally, the location of the largest pore per pit membrane was observed to tend toward the periphery of the membrane.

  1. Aspen Delineation - Sequoia National Forest [ds378

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (SEQUOIA_NF_PTS) collected in aspen stands in the Cannell Meadows Ranger...

  2. Aspen Delineation - Plumas National Forest [ds374

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (PLUMAS_NF_PTS) collected in aspen stands in the Plumas National Forest,...

  3. Aspen Delineation - Lassen National Forest [ds372

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (LASSEN_NF_EAGLELAKE_PTS) collected in aspen stands in the in the Eagle...

  4. Aspen Delineation - Sierra State Parks [ds380

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (SIERRA_SP_PTS) collected in aspen stands on lands administered by the...

  5. Genetic structure of Populus hybrid zone along the Irtysh River provides insight into plastid-nuclear incompatibility.

    Science.gov (United States)

    Zeng, Yan-Fei; Zhang, Jian-Guo; Duan, Ai-Guo; Abuduhamiti, Bawerjan

    2016-06-16

    In plants, the maintenance of species integrity despite hybridization has often been explained by the co-adaption of nuclear gene complexes. However, the interaction between plastid and nuclear sub-genomes has been underestimated. Here, we analyzed the genetic structure of a Populus alba and P. tremula hybrid zone along the Irtysh River system in the Altai region, northwest China, using both nuclear microsatellites and plastid DNA sequences. We found high interspecific differentiation, although the hybrid P. × canescens was prevalent. Bayesian inference classified most hybrids into F1, followed by a few back-crosses to P. alba, and fewer F2 hybrids and back-crosses to P. tremula, indicating a few introgressions but preference toward P. alba. When plastid haplotypes in parental species were distinct, P. × canescens carried the haplotypes of both parents, but showed significant linkage between intraspecific haplotype and nuclear genotypes at several microsatellite loci. Selection, rather than migration and assortative mating, might have contributed to such plastid-nuclear disequilibria. By removing later-generated hybrids carrying interspecific combinations of haplotype and nuclear genotypes, plastid-nuclear incompatibility has greatly limited the gene exchange between P. alba and P. tremula via backcrossing with hybrids, demonstrating a significant association between plastid haplotype and the proportion of nuclear admixture.

  6. Defensive effects of extrafloral nectaries in quaking aspen differ with scale.

    Science.gov (United States)

    Mortensen, Brent; Wagner, Diane; Doak, Patricia

    2011-04-01

    The effects of plant defenses on herbivory can differ among spatial scales. This may be particularly common with indirect defenses, such as extrafloral nectaries (EFNs), that attract predatory arthropods and are dependent on predator distribution, abundance, and behavior. We tested the defensive effects of EFNs in quaking aspen (Populus tremuloides Michx.) against damage by a specialist herbivore, the aspen leaf miner (Phyllocnistis populiella Cham.), at the scale of individual leaves and entire ramets (i.e., stems). Experiments excluding crawling arthropods revealed that the effects of aspen EFNs differed at the leaf and ramet scales. Crawling predators caused similar reductions in the percent leaf area mined on individual leaves with and without EFNs. However, the extent to which crawling predators increased leaf miner mortality and, consequently, reduced mining damage increased with EFN expression at the ramet scale. Thus, aspen EFNs provided a diffuse defense, reducing damage to leaves across a ramet regardless of leaf-scale EFN expression. We detected lower leaf miner damage and survival unassociated with crawling predators on EFN-bearing leaves, suggesting that direct defenses (e.g., chemical defenses) were stronger on leaves with than without EFNs. Greater direct defenses on EFN-bearing leaves may reduce the probability of losing these leaves and thus weakening ramet-scale EFN defense. Aspen growth was not related to EFN expression or the presence of crawling predators over the course of a single season. Different effects of aspen EFNs at the leaf and ramet scales suggest that future studies may benefit from examining indirect defenses simultaneously at multiple scales.

  7. Enzymatic hydrolysis of aspen biomass into fermentable sugars by using lignocellulases from Armillaria gemina.

    Science.gov (United States)

    Jagtap, Sujit Sadashiv; Dhiman, Saurabh Sudha; Kim, Tae-Su; Li, Jinglin; Lee, Jung-Kul; Kang, Yun Chan

    2013-04-01

    A white rot fungus, identified as Armillaria gemina SKU2114 on the basis of morphological and phylogenetic analyses, was found to secrete efficient lignocellulose-degrading enzymes. The strain showed maximum endoglucanase, cellobiohydrolase, and β-glucosidase activities of 146, 34, and 15 U/mL, respectively, and also secreted xylanase, laccase, mannanase, and lignin peroxidase with activities of 1270, 0.16, 57, and 0.31 U/mL, respectively, when grown with rice straw as a carbon source. Among various plant biomasses tested for saccharification, aspen biomass produced the maximum amount of reducing sugar. Response surface methodology was used to optimize the hydrolysis of aspen biomass to achieve the highest level of sugar production. A maximum saccharification yield of 62% (429 mg/g-substrate) was obtained using Populus tomentiglandulosa biomass after 48 h of hydrolysis. A. gemina was shown to be a good option for use in the production of reducing sugars from lignocellulosic biomass.

  8. Root carbon reserve dynamics in aspen seedlings: does simulated drought induce reserve limitation?

    Science.gov (United States)

    Galvez, David A; Landhäusser, S M; Tyree, M T

    2011-03-01

    In a greenhouse study we quantified the gradual change of gas exchange, water relations and root reserves of aspen (Populus tremuloides Michx.) seedlings growing over a 3-month period of severe water stress. The aim of the study was to quantify the complex interrelationship between growth, water and gas exchange, and root carbon (C) dynamics. Various growth, gas exchange and water relations variables in combination with root reserves were measured periodically on seedlings that had been exposed to a continuous drought treatment over a 12-week period and compared with well-watered seedlings. Although gas exchange and water relations parameters significantly decreased over the drought period in aspen seedlings, root reserves did not mirror this trend. During the course of the experiment roots of aspen seedlings growing under severe water stress showed a two orders of magnitude increase in sugar and starch content, and roots of these seedlings contained more starch relative to sugar than those in non-droughted seedlings. Drought resulted in a switch from growth to root reserves storage which indicates a close interrelationship between growth and physiological variables and the accumulation of root carbohydrate reserves. Although a severe 3-month drought period created physiological symptoms of C limitation, there was no indication of a depletion of root C reserve in aspen seedlings.

  9. Imaging spectroscopy links aspen genotype with below-ground processes at landscape scales.

    Science.gov (United States)

    Madritch, Michael D; Kingdon, Clayton C; Singh, Aditya; Mock, Karen E; Lindroth, Richard L; Townsend, Philip A

    2014-01-01

    Fine-scale biodiversity is increasingly recognized as important to ecosystem-level processes. Remote sensing technologies have great potential to estimate both biodiversity and ecosystem function over large spatial scales. Here, we demonstrate the capacity of imaging spectroscopy to discriminate among genotypes of Populus tremuloides (trembling aspen), one of the most genetically diverse and widespread forest species in North America. We combine imaging spectroscopy (AVIRIS) data with genetic, phytochemical, microbial and biogeochemical data to determine how intraspecific plant genetic variation influences below-ground processes at landscape scales. We demonstrate that both canopy chemistry and below-ground processes vary over large spatial scales (continental) according to aspen genotype. Imaging spectrometer data distinguish aspen genotypes through variation in canopy spectral signature. In addition, foliar spectral variation correlates well with variation in canopy chemistry, especially condensed tannins. Variation in aspen canopy chemistry, in turn, is correlated with variation in below-ground processes. Variation in spectra also correlates well with variation in soil traits. These findings indicate that forest tree species can create spatial mosaics of ecosystem functioning across large spatial scales and that these patterns can be quantified via remote sensing techniques. Moreover, they demonstrate the utility of using optical properties as proxies for fine-scale measurements of biodiversity over large spatial scales.

  10. Landscape dynamics in aspen and western juniper woodlands on the Owyhee Plateau, Idaho

    Science.gov (United States)

    Strand, Eva K.

    A century of altered fire regimes has affected the landscape vegetation dynamics in the Intermountain West. Suppression of wildfires has resulted in increases in woody plant cover in these semi-arid ecosystems, which has resulted in land cover changes affecting biogeochemical cycling, landscape composition, and habitat diversity. Recent developments in remote sensing technology, computational power, and a rapid development of analysis techniques have enabled us to quantify such changes at the landscape scale. Wavelet analysis is a powerful image analysis technique that is here applied in a novel fashion to fine scale remote sensing imagery to automatically detect the location and crown diameter of individual western juniper plants (Juniperus occidentalis ssp. occidentalis) expanding into sagebrush (Artemisia spp.) steppe at multiple scales. The produced marked point pattern of historical and current spatial juniper distribution was compared regionally and changes in foliar cover and above ground biomass were estimated across a 330,000 ha area on the Owyhee Plateau, Idaho. The above ground carbon accumulation rate from 1946 to 1998 was estimate to be 3.3 gCm-2yr-1 and 10.0 gCm-2yr -1 employing the wavelet and conventional texture analysis methods, respectively, with an additional 25% rise in belowground carbon accumulation in root stock. This research further demonstrates that estimates of carbon accumulation rates as a result of woody encroachment are highly dependent on the spatial and temporal scales of analysis. Conifer species, western juniper and Douglas-fir (Pseudotsuga menziesii) on the Owyhee Plateau, have further expanded into the biologically important quaking aspen ( Populus tremuloides) habitats resulting in conifer dominance and occasional loss of aspen clones. Classification of remotely sensed imagery combined with spatially explicit modeling of aspen successional stages indicate that, in the absence of management activity, loss of seral aspen stands

  11. Aspen Characteristics - Sequoia National Forest [ds377

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands in the Cannell Meadows Ranger District, Sequoia National...

  12. Aspen Characteristics - Plumas National Forest [ds373

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands in the Plumas National Forest, Beckwourth Ranger District...

  13. Aspen Characteristics - Sierra State Parks [ds379

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands on lands administrated by the Sierra District, California...

  14. Aspen Characteristics - Klamath National Forest [ds369

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected with known aspen stands in the Klamath National Forest, Siskiyou County,...

  15. Drought characteristics drive patterns in widespread aspen forest mortality across the western United States

    Science.gov (United States)

    Anderegg, W.; Anderegg, L.; Abatzoglou, J. T.; Berry, J. A.

    2011-12-01

    Widespread drought-induced forest mortality has been documented across the globe in the last few decades and influences land-atmosphere interactions, biodiversity, carbon sequestration, and biophysical and biogeochemical feedbacks to climate change. These rapid mortality events are currently not well-captured in current vegetation models, limiting the ability to predict them. While many studies have focused on the plant physiological mechanisms that mediate vegetation mortality, the characteristics of drought seasonality, sequence, severity and duration that drive mortality events have received much less attention. These characteristics are particularly relevant in light of changing precipitation regimes, changes to snowpack and snowmelt, and increasing temperature stress associated with climate change. We examine the characteristics of drought associated with the recent widespread mortality of trembling aspen (Populus tremuloides) across much of the western United States. We combine a regional model of watershed-level aspen mortality with in situ tissue isotopic analysis of water source to analyze the roles of drought seasonality, severity, and duration in this mortality event, including raw climate variables, derived drought indices, and variables generated by a climate envelope approach. We found that variables pertaining to spring temperatures and spring-summer water deficit, especially during the peak severity of drought, best capture regional mortality patterns, though multi-year drought variables did improve the model. Field water isotopic analysis of aspen water source over a growing season and during moderate seasonal water stress corroborate the regional model by indicating that aspen clones generally utilize surface water with little plasticity during drought stress. These results suggest that drought characteristics can play an important role in mediating widespread forest mortality and have implications for the future vulnerability of trembling aspen

  16. Effects of widespread drought-induced aspen mortality on understory plants.

    Science.gov (United States)

    Anderegg, William R L; Anderegg, Leander D L; Sherman, Clare; Karp, Daniel S

    2012-12-01

    Forest die-off around the world is expected to increase in coming decades as temperature increases due to climate change. Forest die-off will likely affect understory plant communities, which have substantial influence on regional biological diversity, ecosystem function, and land-atmosphere interactions, but how die-off alters these plant communities is largely unknown. We examined changes in understory plant communities following a widespread, drought-induced die-off of trembling aspen (Populus tremuloides) in the western United States. We assessed shrub and herbaceous cover and volume in quadrats in 55 plots located across a wide range of levels of aspen mortality. We measured species richness and composition of herbaceous plant communities by recording species presence and absence in 12 sets of paired (1 healthy, 1 dying) aspen plots. Although understory composition in healthy and dying stands was heterogeneous across the landscape, shrub abundance, cover, and volume were higher and abundance of herbaceous species, cover, and volume were lower in dying aspen stands. Shrub cover and volume increased from 2009 to 2011 in dying stands, which suggests that shrub growth and expansion is ongoing. Species richness of herbs declined by 23% in dying stands. Composition of herbs differed significantly between dying and healthy stands. Richness of non-native species did not differ between stand types. The understory community in dying aspen stands was not similar to other shrub-dominated plant communities in the region and may constitute a novel community. Our results suggest that changes in understory plant communities as forests die off could be a significant indirect effect of climate change on biological diversity and forest communities.

  17. Aspen Delineation - El Dorado National Forest [ds364

    Data.gov (United States)

    California Department of Resources — The database represents delineations of known aspen stands, where aspen assessments were gathered in the Eldorado National Forest, Eldorado and Amador Counties,...

  18. Aspen Delineation - Klamath National Forest, EUI [ds368

    Data.gov (United States)

    California Department of Resources — The database represents delineations of known aspen stands where aspen assessments were collected in the Klamath National Forest, Siskiyou County, California. The...

  19. Effectiveness of mycorrhizal inoculation in the nursery on root colonization, growth, and nutrient uptake of aspen and balsam poplar

    Energy Technology Data Exchange (ETDEWEB)

    Quoreshi, A.M.; Khasa, D.P. [Symbiotech Research Inc. 201, 509-11 Avenue, Nisku, AB (Canada); Forest Biology Research Centre, University of Laval, Quebec (Canada)

    2008-05-15

    Aspen and balsam poplar seedlings were inoculated with six species of ectomycorrhizal fungi (Hebeloma longicaudum, Laccaria bicolor, Paxillus involutus, Pisolithus tinctorius, Rhizopogon vinicolor, and Suillus tomentosus), one species of endomycorrhizal fungus (Glomus intraradices), two species of bacteria (Agrobacterium sp. and Burkholderia cepacia), treated with a growth hormone (SR3), and co-inoculated with a combination of Paxillus and Burkholderia. The seedlings were grown in a greenhouse under three different fertility regimes. Bacterial inoculation alone did not affect seedling growth and nutrition as observed when co-inoculated with ectomycorrhizal fungus. The biomass and root collar diameter of aspen and balsam poplar were significantly increased when adequate mycorrhizas are formed and more prominent when co-inoculated with P. involutus and B. cepacia and grown at the 67% fertilizer level. Except for R. vinicolor and S. tomentosus, the other four species of ectomycorrhizal fungi and G. intraradices formed symbiotic associations with both plant species. Both ectomycorrhizal and endomycorrhizal colonization were observed at all fertilizer levels and fertilizer applications did not affect the colonization rates. Nitrogen and phosphorus concentrations were significantly improved in both aspen and balsam poplar compared with control only when co-inoculated with P. involutus and B. cepacia. However, plant net nitrogen uptake (content) increased significantly in all successful inoculation treatments and co-inoculated treatment when compared with control. These results hold promise for incorporation of inoculation of Populus sp. with appropriate mycorrhizal fungi and selected bacteria into commercial nursery system to improve the establishment of Populus in various sites. (author)

  20. Aspen Notebook: Cable and Continuing Education.

    Science.gov (United States)

    Adler, Richard; Baer, Walter S.

    This is the first of a planned series of Aspen Notebooks on cable television (CATV). Part I reports on research conducted by the Aspen Workshop on Uses of the Cable. It describes the status of continuing education and the history of educational television and explores the prospects created by cable's development for extending access to continuing…

  1. Populus seed fibers as a natural source for production of oil super absorbents.

    Science.gov (United States)

    Likon, Marko; Remškar, Maja; Ducman, Vilma; Švegl, Franc

    2013-01-15

    The genus Populus, which includes poplars, cottonwoods and aspen trees, represents a huge natural source of fibers with exceptional physical properties. In this study, the oil absorption properties of poplar seed hair fibers obtained from Populus nigra italica when tested with high-density motor oil and diesel fuel are reported. Poplar seed hair fibers are hollow hydrophobic microtubes with an external diameter between 3 and 12 μm, an average length of 4±1 mm and average tube wall thickness of 400±100 nm. The solid skeleton of the hollow fibers consists of lignocellulosic material coated by a hydrophobic waxy coating. The exceptional chemical, physical and microstructural properties of poplar seed hair fibers enable super-absorbent behavior with high absorption capacity for heavy motor oil and diesel fuel. The absorption values of 182-211 g heavy oil/g fiber and 55-60 g heavy oil/g fiber for packing densities of 0.005 g/cm(3) and 0.02 g/cm(3), respectively, surpass all known natural absorbents. Thus, poplar seed hair fibers obtained from Populus nigra italica and other trees of the genus Populus are an extremely promising natural source for the production of oil super absorbents.

  2. Acute O 3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment.

    Science.gov (United States)

    Darbah, Joseph N T; Jones, Wendy S; Burton, Andrew J; Nagy, John; Kubiske, Mark E

    2011-09-01

    We studied the effect of high ozone (O(3)) concentration (110-490 nmol mol(-1)) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O(3) pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O(3) exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O(3) and/or CO(2) for 12 years, were harvested. Acute O(3) damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O(3) damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O(3) damage as it directly controlled O(3) uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O(3) exposure. Moreover, elevated CO(2) did not ameliorate the adverse effects of acute O(3) dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O(3) levels.

  3. Acute O3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment

    Energy Technology Data Exchange (ETDEWEB)

    Darbah, J.N.; Nagy, J.; Jones, W. S.; Burton, A. J.; Kubiske, M. E.

    2011-10-01

    We studied the effect of high ozone (O{sub 3}) concentration (110-490 nmol mol{sup -1}) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O{sub 3} pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O{sub 3} exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O{sub 3} and/or CO{sub 2} for 12 years, were harvested. Acute O{sub 3} damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O{sub 3} damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O{sub 3} damage as it directly controlled O{sub 3} uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O{sub 3} exposure. Moreover, elevated CO{sub 2} did not ameliorate the adverse effects of acute O{sub 3} dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O{sub 3} levels.

  4. Climatic Sensitivity of a Mixed Forest Association of White Spruce and Trembling Aspen at Their Southern Range Limit

    Directory of Open Access Journals (Sweden)

    Sophan Chhin

    2016-10-01

    Full Text Available Climatic sensitivity of white spruce (Picea glauca (Moench Voss was examined growing in association with trembling aspen (Populus tremuloides Michx. at their southern limit of distribution in a transitional ecotone between the southern boreal forest and northern prairie region. The study was carried out in the Spruce Woods Provincial Park (SWPP located in southwestern Manitoba, Canada. The dry regional climate restricted trembling aspen growth during the growing season via moisture deficiency and temperature induced drought stress. Warm, mild winters also negatively affected radial growth of trembling aspen. Growth of white spruce was moderated by conditions within the aspen stands as radial growth patterns showed low variability from year to year, a low common growth signal, and a stronger response to temperature than to precipitation. Nonetheless, the dry regional climate still restricted growth of white spruce during the growing season via temperature induced drought stress. The findings of the study for white spruce support the stress gradient hypothesis in which facilitative interactions between tree species are expected under harsher environmental conditions.

  5. Changes in sulphur metabolism of grey poplar (Populus x canescens) leaves during salt stress: a metabolic link to photorespiration.

    Science.gov (United States)

    Herschbach, Cornelia; Teuber, Markus; Eiblmeier, Monika; Ehlting, Barbara; Ache, Peter; Polle, Andrea; Schnitzler, Jörg-Peter; Rennenberg, Heinz

    2010-09-01

    The poplar hybrid Populus x canescens (syn. Populus tremula x Populus alba) was subjected to salt stress by applying 75 mM NaCl for 2 weeks in hydroponic cultures. Decreasing maximum quantum yield (Fv/Fm) indicated damage of photosystem II (PS II), which was more pronounced under nitrate compared with ammonium nutrition. In vivo staining with diaminobenzidine showed no accumulation of H(2)O(2) in the leaf lamina; moreover, staining intensity even decreased. But at the leaf margins, development of necrotic tissue was associated with a strong accumulation of H(2)O(2). Glutathione (GSH) contents increased in response to NaCl stress in leaves but not in roots, the primary site of salt exposure. The increasing leaf GSH concentrations correlated with stress-induced decreases in transpiration and net CO(2) assimilation rates at light saturation. Enhanced rates of photorespiration could also be involved in preventing reactive oxygen species formation in chloroplasts and, thus, in protecting PS II from damage. Accumulation of Gly and Ser in leaves indeed indicates increasing rates of photorespiration. Since Ser and Gly are both immediate precursors of GSH that can limit GSH synthesis, it is concluded that the salt-induced accumulation of leaf GSH results from enhanced photorespiration and is thus probably restricted to the cytosol.

  6. Adapting ASPEN for Orbital Express

    Science.gov (United States)

    Chouinard, Caroline; Tran, Daniel; Jones, Grailing; Dang, Van; Knight, Russell

    2010-01-01

    By studying the Orbital Express mission, modeling the spacecraft and scenarios, and testing the system, a technique has been developed that uses recursive decomposition to represent procedural actions declaratively, schema-level uncertainty reasoning to make uncertainty reasoning tractable, and lightweight, natural language processing to automatically parse procedures to produce declarative models. Schema-level uncertainty reasoning has, at its core, the basic assumption that certain variables are uncertain, but not independent. Once any are known, then the others become known. This is important where a variable is uncertain for an action and many actions of the same type exist in the plan. For example, if the number of retries to purge pump lines was unknown (but bounded), and each attempt required a sub-plan, then, once the correct number of attempts required for a purge was known, it would likely be the same for all subsequent purges. This greatly reduces the space of plans that needs to be searched to ensure that all executions are feasible. To accommodate changing scenario procedures, each is ingested into a tabular format in temporal order, and a simple natural-language parser is used to read each step and to derive the impact of that step on memory, power, and communications. Then an ASPEN (Activity Scheduling and Planning Environment) model is produced based on this analysis. The model is tested and further changed by hand, if necessary, to reflect the actual procedure. This results in a great savings of time used for modeling procedures. Many processes that need to be modeled in ASPEN (a declarative system) are, in fact, procedural. ASPEN includes the ability to model activities in a hierarchical fashion, but this representation breaks down if there is a practically unbounded number of sub-activities and decomposition topologies. However, if recursive decomposition is allowed, HTN-like encodings are enabled to represent most procedural phenomena. For

  7. Vegetation, land surface brightness, and temperature dynamics after aspen forest die-off

    Science.gov (United States)

    Huang, Cho-ying; Anderegg, William R. L.

    2014-07-01

    Forest dynamics following drought-induced tree mortality can affect regional climate through biophysical surface properties. These dynamics have not been well quantified, particularly at the regional scale, and are a large uncertainty in ecosystem-climate feedback. We investigated regional biophysical characteristics through time (1995-2011) in drought-impacted (2001-2003), trembling aspen (Populus tremuloides Michx.) forests by utilizing Landsat time series green and brown vegetation cover, surface brightness (total shortwave albedo), and daytime land surface temperature. We quantified the temporal dynamics and postdrought recovery of these characteristics for aspen forests experiencing severe drought-induced mortality in the San Juan National Forest in southwestern Colorado, USA. We partitioned forests into three categories from healthy to severe mortality (Healthy, Intermediate, and Die-off) by referring to field observations of aspen canopy mortality and live aboveground biomass losses. The vegetation cover of die-off areas in 2011 (26.9% of the aspen forest) was significantly different compared to predrought conditions (decrease of 7.4% of the green vegetation cover and increase of 12.1% of the brown vegetation cover compared to 1999). The surface brightness of the study region 9 years after drought however was comparable to predrought estimates (12.7-13.7%). Postdrought brightness was potentially influenced by understory shrubs, since they became the top layer green canopies in disturbed sites from a satellite's point of view. Satellite evidence also showed that the differences of land surface temperature among the three groups increased substantially (≥45%) after drought, possibly due to the reduction of plant evapotranspiration in the Intermediate and Die-off sites. Our results suggest that the mortality-affected systems have not recovered in terms of the surface biophysical properties. We also find that the temporal dynamics of vegetation cover holds

  8. Aspen Characteristics - Lassen National Forest [ds371

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected in aspen stands in the in the Eagle Lake Ranger District, Lassen National...

  9. Variation in Trembling Aspen and White Spruce Wood Quality Grown in Mixed and Single Species Stands in the Boreal Mixedwood Forest

    Directory of Open Access Journals (Sweden)

    Francis De Araujo

    2015-05-01

    Full Text Available The Canadian boreal forest is largely represented by mixed wood forests of white spruce (Picea glauca (Moench Voss and trembling aspen (Populus tremuloides Michx. In this study, a total of 300 trees originating from three sites composed of trembling aspen and white spruce with varying compositions were investigated for wood quality traits: one site was composed mainly of aspen, one mainly of spruce and a third was a mixed site. Four wood quality traits were examined: wood density, microfibril angle (MFA, fibre characteristics, and cell wall chemistry. Social classes were also determined for each site in an attempt to provide a more in-depth comparison. Wood density showed little variation among sites for both species, with only significant differences occurring between social classes. The aspen site showed statistically lower MFAs than the aspen from the mixed site, however, no differences were observed when comparing spruce. Fibre characteristics were higher in the pure species sites for both species. There were no differences in carbohydrate contents across sites, while lignin content varied. Overall, the use of social classes did not refine the characterization of sites.

  10. Aspen Delineation - Plumas National Forest, FRRD [ds376

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (PLUMAS_NF_FEATHERRIVER_PTS) collected in aspen stands in the Plumas...

  11. Behavioral archives link the chemistry and clonal structure of trembling aspen to the food choice of North American porcupine.

    Science.gov (United States)

    Diner, Brandee; Berteaux, Dominique; Fyles, Jim; Lindroth, Richard L

    2009-07-01

    Understanding the links among plant genotype, plant chemistry, and food selection by vertebrate herbivores is critical to assess the role of herbivores in the evolution of plant secondary chemistry. Some specialized vertebrate herbivores have been shown to select plants differentially according to plant genotype, but examples from generalists, which constitute the vast majority of vertebrate herbivores, are few, especially in natural conditions. We examined the relationship between the North American porcupine (Erethizon dorsatum), a generalist mammalian herbivore, and clonal trembling aspen (Populus tremuloides), a preferred food source of porcupines. We determined preference for certain aspen trees through visual examination of porcupine climbing scars left on tree bark, and through a controlled feeding experiment. We used genetic and biochemical analyses to link the behavioral archives (climbing scars) left by porcupines on aspen trunks to the clonal structure and chemical composition of trees. We show that two phenolic glycosides (tremulacin and salicortin), which are under a high degree of genetic control and thus vary in concentration across clones, are the chemical variables that most influence (deter) feeding choices by porcupines. Using behavioral archives left by a wild herbivore on a natural stand of plants thus allowed us to demonstrate that a generalist vertebrate herbivore can choose plants according to their clonal structure and genetically based chemical composition. Our results contribute to extending previous findings obtained with generalist herbivores studied in controlled conditions, and with specialist herbivores studied in the field.

  12. Heterozygosity, gender, and the growth-defense trade-off in quaking aspen.

    Science.gov (United States)

    Cole, Christopher T; Stevens, Michael T; Anderson, Jon E; Lindroth, Richard L

    2016-06-01

    Although plant growth is generally recognized to be influenced by allocation to defense, genetic background (e.g., inbreeding), and gender, rarely have those factors been addressed collectively. In quaking aspen (Populus tremuloides Michx.), phenolic glycosides (PGs) and condensed tannins (CTs) constitute up to 30 % of leaf dry weight. To quantify the allocation cost of this chemical defense, we measured growth, defense chemistry, and individual heterozygosity (H obs at 16 microsatellite loci) for male and female trees in both controlled and natural environments. The controlled environment consisted of 12 juvenile genets grown for 3 years in a common garden, with replication. The natural environment consisted of 51 mature genets in wild populations, from which we sampled multiple ramets (trees) per genet. Concentrations of PGs and CTs were negatively correlated. PGs were uncorrelated with growth, but CT production represented a major cost. Across the range of CT levels found in wild-grown trees, growth rates varied by 2.6-fold, such that a 10 % increase in CT concentration occurred with a 38.5 % decrease in growth. H obs had a marked effect on aspen growth: for wild trees, a 10 % increase in H obs corresponded to a 12.5 % increase in growth. In wild trees, this CT effect was significant only in females, in which reproduction seems to exacerbate the cost of defense, while the H obs effect was significant only in males. Despite the lower growth rate of low-H obs trees, their higher CT levels may improve survival, which could account for the deficit of heterozygotes repeatedly found in natural aspen populations.

  13. Interactions between Bacteria And Aspen Defense Chemicals at the Phyllosphere - Herbivore Interface.

    Science.gov (United States)

    Mason, Charles J; Lowe-Power, Tiffany M; Rubert-Nason, Kennedy F; Lindroth, Richard L; Raffa, Kenneth F

    2016-03-01

    Plant- and insect-associated microorganisms encounter a diversity of allelochemicals, and require mechanisms for contending with these often deleterious and broadly-acting compounds. Trembling aspen, Populus tremuloides, contains two principal groups of defenses, phenolic glycosides (salicinoids) and condensed tannins, which differentially affect the folivorous gypsy moth, Lymantria dispar, and its gut symbionts. The bacteria genus Acinetobacter is frequently associated with both aspen foliage and gypsy moth consuming that tissue, and one isolate, Acinetobacter sp. R7-1, previously has been shown to metabolize phenolic glycosides. In this study, we aimed to characterize further interactions between this Acinetobacter isolate and aspen secondary metabolites. We assessed bacterial carbon utilization and growth in response to different concentrations of phenolic glycosides and condensed tannins. We also tested if enzyme inhibitors reduce bacterial growth and catabolism of phenolic glycosides. Acinetobacter sp. R7-1 utilized condensed tannins but not phenolic glycosides or glucose as carbon sources. Growth in nutrient-rich medium was increased by condensed tannins, but reduced by phenolic glycosides. Addition of the P450 enzyme inhibitor piperonyl butoxide increased the effects of phenolic glycosides on Acinetobacter sp. R7-1. In contrast, the esterase inhibitor S,S,S,-tributyl-phosphorotrithioate did not affect phenolic glycoside inhibition of bacterial growth. Degradation of phenolic glycosides by Acinetobacter sp. R7-1 appears to alleviate the cytotoxicity of these compounds, rather than provide an energy source. Our results further suggest this bacterium utilizes additional, complementary mechanisms to degrade antimicrobial phytochemicals. Collectively, these results provide insight into mechanisms by which microorganisms contend with their environment within the context of plant-herbivore interactions.

  14. The genome sequence of black cottonwood (Populus trichocarpa) reveals 18 conserved cellulose synthase (CesA) genes.

    Science.gov (United States)

    Djerbi, Soraya; Lindskog, Mats; Arvestad, Lars; Sterky, Fredrik; Teeri, Tuula T

    2005-07-01

    The genome sequence of Populus trichocarpa was screened for genes encoding cellulose synthases by using full-length cDNA sequences and ESTs previously identified in the tissue specific cDNA libraries of other poplars. The data obtained revealed 18 distinct CesA gene sequences in P. trichocarpa. The identified genes were grouped in seven gene pairs, one group of three sequences and one single gene. Evidence from gene expression studies of hybrid aspen suggests that both copies of at least one pair, CesA3-1 and CesA3-2, are actively transcribed. No sequences corresponding to the gene pair, CesA6-1 and CesA6-2, were found in Arabidopsis or hybrid aspen, while one homologous gene has been identified in the rice genome and an active transcript in Populus tremuloides. A phylogenetic analysis suggests that the CesA genes previously associated with secondary cell wall synthesis originate from a single ancestor gene and group in three distinct subgroups. The newly identified copies of CesA genes in P. trichocarpa give rise to a number of new questions concerning the mechanism of cellulose synthesis in trees.

  15. Clone history shapes Populus drought responses.

    Science.gov (United States)

    Raj, Sherosha; Bräutigam, Katharina; Hamanishi, Erin T; Wilkins, Olivia; Thomas, Barb R; Schroeder, William; Mansfield, Shawn D; Plant, Aine L; Campbell, Malcolm M

    2011-07-26

    Just as animal monozygotic twins can experience different environmental conditions by being reared apart, individual genetically identical trees of the genus Populus can also be exposed to contrasting environmental conditions by being grown in different locations. As such, clonally propagated Populus trees provide an opportunity to interrogate the impact of individual environmental history on current response to environmental stimuli. To test the hypothesis that current responses to an environmental stimulus, drought, are contingent on environmental history, the transcriptome- level drought responses of three economically important hybrid genotypes-DN34 (Populus deltoides × Populus nigra), Walker [P. deltoides var. occidentalis × (Populus laurifolia × P. nigra)], and Okanese [Walker × (P. laurifolia × P. nigra)]-derived from two different locations were compared. Strikingly, differences in transcript abundance patterns in response to drought were based on differences in geographic origin of clones for two of the three genotypes. This observation was most pronounced for the genotypes with the longest time since establishment and last common propagation. Differences in genome-wide DNA methylation paralleled the transcriptome level trends, whereby the clones with the most divergent transcriptomes and clone history had the most marked differences in the extent of total DNA methylation, suggesting an epigenomic basis for the clone history-dependent transcriptome divergence. The data provide insights into the interplay between genotype and environment in the ecologically and economically important Populus genus, with implications for the industrial application of Populus trees and the evolution and persistence of these important tree species and their associated hybrids.

  16. The SHORT-ROOT-like gene PtSHR2B is involved in Populus phellogen activity.

    Science.gov (United States)

    Miguel, Andreia; Milhinhos, Ana; Novák, Ondřej; Jones, Brian; Miguel, Célia M

    2016-03-01

    SHORT-ROOT (SHR) is a GRAS transcription factor first characterized for its role in the specification of the stem cell niche and radial patterning in Arabidopsis thaliana (At) roots. Three SHR-like genes have been identified in Populus trichocarpa (Pt). PtSHR1 shares high similarity with AtSHR over the entire length of the coding sequence. The two other Populus SHR-like genes, PtSHR2A and PtSHR2B, are shorter in their 5' ends when compared with AtSHR. Unlike PtSHR1, that is expressed throughout the cambial zone of greenhouse-grown Populus trees, PtSHR2Bprom:uidA expression was detected in the phellogen. Additionally, PtSHR1 and PtSHR2B expression patterns markedly differ in the shoot apex and roots of in vitro plants. Transgenic hybrid aspen expressing PtSHR2B under the 35S constitutive promoter showed overall reduced tree growth while the proportion of bark increased relative to the wood. Reverse transcription-quantitative PCR (RT-qPCR) revealed increased transcript levels of cytokinin metabolism and response-related genes in the transgenic plants consistent with an increase of total cytokinin levels. This was confirmed by cytokinin quantification by LC-MS/MS. Our results indicate that PtSHR2B appears to function in the phellogen and therefore in the regulation of phellem and periderm formation, possibly acting through modulation of cytokinin homeostasis. Furthermore, this work points to a functional diversification of SHR after the divergence of the Populus and Arabidopsis lineages. This finding may contribute to selection and breeding strategies of cork oak in which, unlike Populus, the phellogen is active throughout the entire tree lifespan, being at the basis of a highly profitable cork industry.

  17. DNA damage in Populus tremuloides clones exposed to elevated O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Tai, Helen H., E-mail: helen.tai@agr.gc.c [Agriculture and Agri-Food Canada, Potato Research Centre, P.O. Box 20280, Fredericton, New Brunswick, E3B 4Z7 (Canada); Natural Resources Canada, Canadian Forest Service - Atlantic Forestry Centre, 1350 Regent Street S., Fredericton, New Brunswick, E3B 5P7 (Canada); Percy, Kevin E. [Natural Resources Canada, Canadian Forest Service - Atlantic Forestry Centre, 1350 Regent Street S., Fredericton, New Brunswick, E3B 5P7 (Canada); Karnosky, David F. [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States)

    2010-04-15

    The effects of elevated concentrations of atmospheric tropospheric ozone (O{sub 3}) on DNA damage in five trembling aspen (Populus tremuloides Michx.) clones growing in a free-air enrichment experiment in the presence and absence of elevated concentrations of carbon dioxide (CO{sub 2}) were examined. Growing season mean hourly O{sub 3} concentrations were 36.3 and 47.3 ppb for ambient and elevated O{sub 3} plots, respectively. The 4th highest daily maximum 8-h ambient and elevated O{sub 3} concentrations were 79 and 89 ppb, respectively. Elevated CO{sub 2} averaged 524 ppm (+150 ppm) over the growing season. Exposure to O{sub 3} and CO{sub 2} in combination with O{sub 3} increased DNA damage levels above background as measured by the comet assay. Ozone-tolerant clones 271 and 8L showed the highest levels of DNA damage under elevated O{sub 3} compared with ambient air; whereas less tolerant clone 216 and sensitive clones 42E and 259 had comparably lower levels of DNA damage with no significant differences between elevated O{sub 3} and ambient air. Clone 8L was demonstrated to have the highest level of excision DNA repair. In addition, clone 271 had the highest level of oxidative damage as measured by lipid peroxidation. The results suggest that variation in cellular responses to DNA damage between aspen clones may contribute to O{sub 3} tolerance or sensitivity. - Ozone tolerant clones and sensitive Populus tremuloides clones show differences in DNA damage and repair.

  18. Aspen Winter Conferences on High Energy

    Energy Technology Data Exchange (ETDEWEB)

    multiple speakers, presenters listed on link below

    2011-02-12

    The 2011 Aspen Winter Conference on Particle Physics was held at the Aspen Center for Physics from February 12 to February 18, 2011. Ninety-four participants from ten countries, and several universities and national labs attended the workshop titled, �New Data From the Energy Frontier.� There were 54 formal talks, and a considerable number of informal discussions held during the week. The week�s events included a public lecture (�The Hunt for the Elusive Higgs Boson� given by Ben Kilminster from Ohio State University) and attended by 119 members of the public, and a physics caf� geared for high schoolers that is a discussion with physicists. The 2011 Aspen Winter Conference on Astroparticle physics held at the Aspen Center for Physics was �Indirect and Direct Detection of Dark Matter.� It was held from February 6 to February 12, 2011. The 70 participants came from 7 countries and attended 53 talks over five days. Late mornings through the afternoon are reserved for informal discussions. In feedback received from participants, it is often these unplanned chats that produce the most excitement due to working through problems with fellow physicists from other institutions and countries or due to incipient collaborations. In addition, Blas Cabrera of Stanford University gave a public lecture titled �What Makes Up Dark Matter.� There were 183 members of the general public in attendance. Before the lecture, 45 people attended the physics caf� to discuss dark matter. This report provides the attendee lists, programs, and announcement posters for each event.

  19. 77 FR 60373 - Monroe Mountain Aspen Ecosystems Restoration Project Fishlake National Forest; Sevier and Piute...

    Science.gov (United States)

    2012-10-03

    ... Forest Service Monroe Mountain Aspen Ecosystems Restoration Project Fishlake National Forest; Sevier and... alternatives, within the Monroe Mountain Aspen Ecosystems Restoration Project area. The purpose of the Monroe Mountain Aspen Ecosystems Restoration Project is to implement land management activities that...

  20. Automated Design Space Exploration with Aspen

    Directory of Open Access Journals (Sweden)

    Kyle L. Spafford

    2015-01-01

    Full Text Available Architects and applications scientists often use performance models to explore a multidimensional design space of architectural characteristics, algorithm designs, and application parameters. With traditional performance modeling tools, these explorations forced users to first develop a performance model and then repeatedly evaluate and analyze the model manually. These manual investigations proved laborious and error prone. More importantly, the complexity of this traditional process often forced users to simplify their investigations. To address this challenge of design space exploration, we extend our Aspen (Abstract Scalable Performance Engineering Notation language with three new language constructs: user-defined resources, parameter ranges, and a collection of costs in the abstract machine model. Then, we use these constructs to enable automated design space exploration via a nonlinear optimization solver. We show how four interesting classes of design space exploration scenarios can be derived from Aspen models and formulated as pure nonlinear programs. The analysis tools are demonstrated using examples based on Aspen models for a three-dimensional Fast Fourier Transform, the CoMD molecular dynamics proxy application, and the DARPA Streaming Sensor Challenge Problem. Our results show that this approach can compose and solve arbitrary performance modeling questions quickly and rigorously when compared to the traditional manual approach.

  1. Genic diversity of natural populations of a clone-forming tree Populus tremuloides

    Energy Technology Data Exchange (ETDEWEB)

    Cheliak, W.M.; Dancik, B.P.

    1982-01-01

    Effects of asexual reproduction as a primary reproductive strategy on population structure and levels of variability were investigated electrophoretically in natural populations of a woody plant species, trembling aspen (Populus tremuloides Michx.). from Alberta. As expected, levels of genic diversity, 42%, and proportion of polymorphic loci, 92%, averaged over all clones are considerably greater than those reported for comparable samples of sexually reproducing plant and animal species. These measures of genic variability of a primary asexual plant species are similar to those reported for asexual species of insects, fish and bacteria. In addition, each of 222 clones was electrophoretically unique. Since neutral theory would predict each individual clone to be heterozygous for a unique mutation at each gene locus at equilibrium, these results can be interpreted in a number of ways: (i) insufficient time to reach equilibrium, (ii) inability of electrophoresis to detect all variation at a locus, (iii) periodic establishment of sexually derived propagules in the population, and (iv) selection for similar genotypes at each location or against mutations at particular gene loci. Re-invasion of Pleistocene-glaciated areas by trembling aspen was likely by sexual means, with subsequent reproduction being primarily asexual. (Refs. 26)

  2. Aspen Characteristics - El Dorado National Forest [ds363

    Data.gov (United States)

    California Department of Resources — The database represents aspen stand locations and field assessments conducted in the Eldorado National Forest, Eldorado and Amador Counties, California. Data was...

  3. Aspen Characteristics - Plumas National Forest, FRRD [ds375

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands in the Plumas National Forest, Feather River Ranger...

  4. Aspen Open Solver接口技术研究%Study on Aspen Open Solver Interfaces

    Institute of Scientific and Technical Information of China (English)

    陈智强; 陈曦; 邵之江; 张正江

    2007-01-01

    Aspen Open Solver接口集中的非线性代数方程组(NLA)部分作为研究对象,在对接口集进行系统地分析之后,利用AspenTech提供的接口代码将分别基于梯度和非基于梯度的四种求解算法嵌入生成solver组件,并实现用Aspen Plus调用该solver组件观察各种算法嵌入的结果.

  5. Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. II. Zinc binding inside leaf cell organelles

    Energy Technology Data Exchange (ETDEWEB)

    Vollenweider, Pierre, E-mail: pierre.vollenweider@wsl.c [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Bernasconi, Petra [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Environmental Protection Office (AfU), Aabachstrasse 5, 6300 Zug (Switzerland); Gautschi, Hans-Peter [Centre for Microscopy and Image Analysis (CMI), University of Zurich, Gloriastrasse 30, 8006 Zuerich (Switzerland); Menard, Terry; Frey, Beat; Guenthardt-Goerg, Madeleine S. [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland)

    2011-01-15

    The phytoextraction potential of plants for removing heavy metals from polluted soils is determined by their capacity to store contaminants in aboveground organs and complex them safely. In this study, the metal compartmentation, elemental composition of zinc deposits and zinc complexation within leaves from poplars grown on soil with mixed metal contamination was analysed combining several histochemical and microanalytical approaches. Zinc was the only heavy metal detected and was stored in several organelles in the form of globoid deposits showing {beta}-metachromasy. It was associated to oxygen anions and different cations, noteworthy phosphorous. The deposit structure, elemental composition and element ratios indicated that zinc was chelated by phytic acid ligands. Maturation processes in vacuolar vs. cytoplasmic deposits were suggested by differences in size and amounts of complexed zinc. Hence, zinc complexation by phytate contributed to metal detoxification and accumulation in foliage but could not prevent toxicity reactions therein. - Zinc contaminants translocated to symplast of aged leaves were detoxified by phytic acid ligands.

  6. Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. I. From the tree crown to leaf cell level

    Energy Technology Data Exchange (ETDEWEB)

    Vollenweider, Pierre, E-mail: pierre.vollenweider@wsl.c [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Menard, Terry; Guenthardt-Goerg, Madeleine S. [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland)

    2011-01-15

    In order to achieve efficient phytoextraction of heavy metals using trees, the metal allocation to aboveground tissues needs to be characterised. In his study, the distribution of heavy metals, macro- and micronutrients and the metal micro-localisation as a function of the leaf position and heavy metal treatment were analysed in poplars grown on soil with mixed metal contamination. Zinc was the most abundant contaminant in both soil and foliage and, together with cadmium, was preferentially accumulated in older foliage whereas excess copper and lead were not translocated. Changes in other element concentrations indicated an acceleration in aging as a consequence of the metal treatment. Excess zinc was irregularly accumulated inside leaf tissues, tended to saturate the veins and was more frequently stored in cell symplast than apoplast. Storage compartments including metabolically safe and sensitive subcellular sites resulted in sizable metal accumulation as well as stress reactions. - Within foliage of poplars growing on contaminated soils, Zinc was stored at metabolically safe as well as sensitive subcellular sites, ensuring sizable bioaccumulation but also causing injuries.

  7. Development of a threshold model to predict germination of Populus tomentosa seeds after harvest and storage under ambient condition.

    Directory of Open Access Journals (Sweden)

    Wei-Qing Wang

    Full Text Available Effects of temperature, storage time and their combination on germination of aspen (Populus tomentosa seeds were investigated. Aspen seeds were germinated at 5 to 30°C at 5°C intervals after storage for a period of time under 28°C and 75% relative humidity. The effect of temperature on aspen seed germination could not be effectively described by the thermal time (TT model, which underestimated the germination rate at 5°C and poorly predicted the time courses of germination at 10, 20, 25 and 30°C. A modified TT model (MTT which assumed a two-phased linear relationship between germination rate and temperature was more accurate in predicting the germination rate and percentage and had a higher likelihood of being correct than the TT model. The maximum lifetime threshold (MLT model accurately described the effect of storage time on seed germination across all the germination temperatures. An aging thermal time (ATT model combining both the TT and MLT models was developed to describe the effect of both temperature and storage time on seed germination. When the ATT model was applied to germination data across all the temperatures and storage times, it produced a relatively poor fit. Adjusting the ATT model to separately fit germination data at low and high temperatures in the suboptimal range increased the models accuracy for predicting seed germination. Both the MLT and ATT models indicate that germination of aspen seeds have distinct physiological responses to temperature within a suboptimal range.

  8. Changes in avian and plant communities of aspen woodlands over 12 years after livestock removal in the Northwestern Great Basin.

    Science.gov (United States)

    Earnst, Susan L; Dobkin, David S; Ballard, Jennifer A

    2012-10-01

    Riparian and quaking aspen (Populus tremuloides) woodlands are centers of avian abundance and diversity in the western United States, but they have been affected adversely by land use practices, particularly livestock grazing. In 1990, cattle were removed from a 112,500-ha national wildlife refuge in southeastern Oregon. Thereafter, we monitored changes in vegetation and bird abundance in years 1-3 (phase 1) and 10-12 (phase 2) in 17 riparian and 9 snow-pocket aspen plots. On each 1.5-ha plot, we sampled vegetation in 6 transects. Three times during each breeding season, observers recorded all birds 50 m to each side of the plot's 150-m centerline for 25 minutes. We analyzed data with multivariate analysis of variance and paired t tests with p values adjusted for multiple comparisons. In both periods, riparian and snow-pocket aspen produced extensive regeneration of new shoots (stems/ha and 7079 stems/ha, respectively). By phase 2, a 64% increase in medium-diameter trees in riparian stands indicated successful recruitment into the overstory, but this pattern was not seen in snow-pocket stands, where the density of trees was over 2 times greater. By phase 2 in riparian and snow-pocket stands, native forb cover had increased by 68% and 57%, respectively, mesic shrub cover had increased by 29% and 58%, and sagebrush cover had decreased by 24% and 31%. Total avian abundance increased by 33% and 39% in riparian and snow-pocket aspen, respectively, ground or understory nesters increased by 133% and 67% and overstory nesters increased by 34% and 33%. Similarly, ground or understory foragers increased by 25% and 32%, aerial foragers by 55% and 57%, and overstory foragers by 66% and 43%. We interpreted the substantial regeneration of aspen shoots, increased densities of riparian forbs and shrubs, and increased avian abundances as a multitrophic-level response to the total removal of livestock and as substantial movement toward recovery of biological integrity.

  9. Organo-mineral interactions promote greater soil organic carbon stability under aspen in semi-arid montane forests in Utah

    Science.gov (United States)

    Van Miegroet, H.; Roman Dobarco, M.

    2014-12-01

    Forest species influence soil organic carbon (SOC) storage through litter input, which in interaction with soil microclimate, texture and mineralogy, lead to different SOC stabilization and storage patterns. We sampled mineral soil (0-15 cm) across the ecotone between aspen (Populus tremuloides) and mixed conifers stands (Abies lasiocarpa and Pseudotsuga menziesii) in semi-arid montane forests from Utah, to investigate the influence of vegetation vs. site characteristics on SOC stabilization, storage and chemistry. SOC was divided into light fraction (LF), mineral-associated SOC in the silt and clay fraction (MoM), and a dense subfraction > 53 μm (SMoM) using wet sieving and electrostatic attraction. SOC decomposability and solubility was derived from long term laboratory incubations and hot water extractions (HWE). Fourier transform infrared spectroscopy (FTIR) was used to study differences in chemical functional groups in LF and MoM. Vegetation cover did not affect SOC storage (47.0 ± 16.5 Mg C ha-1), SOC decomposability (cumulative CO2-C release of 93.2 ± 65.4 g C g-1 C), or SOC solubility (9.8 ± 7.2 mg C g-1 C), but MoM content increased with presence of aspen [pure aspen (31.2 ± 15.1 Mg C ha-1) > mixed (25.7 ± 8.8 Mg C ha-1) > conifer (22.8 ± 9.0 Mg C ha-1)]. Organo-mineral complexes reduced biological availability of SOC, indicated by the negative correlation between silt+clay (%) and decomposable SOC per gram of C (r = -0.48, p = 0.001) or soluble SOC (r = -0.59, p < 0.0001). FTIR spectral analysis indicated that higher MoM content under aspen was not due to higher concentration of recalcitrant compounds (e.g., aliphatic and aromatic C), but rather to stabilization of simple molecules (e.g., polysaccharides) of plant or microbial origin. FTIR spectra clustered by sites with similar parent material rather than by vegetation cover. This suggests that initial differences in litter chemistry between aspen and conifers converged into similar MoM chemistry

  10. Aspen Competition Drives Innovative Ideas for Community Colleges

    Science.gov (United States)

    Gonzalez, Jennifer

    2012-01-01

    When Valencia College became the first recipient of the Aspen Prize for Community College Excellence last month, an unsung sector earned uncommon recognition. Now that the speeches are over and the prize money has been awarded, the Aspen Institute is sharing early lessons from its yearlong effort to determine the top community college in the…

  11. What Is Community College Excellence? Lessons from the Aspen Prize

    Science.gov (United States)

    Wyner, Joshua

    2012-01-01

    Over the past year, in a process to select the winner of the Aspen Prize for Community College Excellence, the Aspen Institute has convened national experts to define and determine how to measure "excellence," to identify community colleges with high levels of student success, and to help more community colleges understand what can be done to…

  12. Aspen Handbook on the Media: Research, Publications, Organizations.

    Science.gov (United States)

    Rivers, William L., Ed.; Slater, William T., Ed.

    The Aspen Program on Communications and Society represents a major attempt to bring together men, ideas, and institutions to pioneer in the communications field, to identify the main communications issues confronting society, and to develop effective programs to implement these policies. This handbook was compiled as a result of an Aspen program…

  13. Modelling growth-competition relationships in trembling aspen and white spruce mixed boreal forests of Western Canada.

    Directory of Open Access Journals (Sweden)

    Jian-Guo Huang

    Full Text Available We examined the effect of competition on stem growth of Picea glauca and Populus tremuloides in boreal mixedwood stands during the stem exclusion stage. We combined traditional approaches of collecting competition data with dendrochronology to provide retrospective measurements of stem diameter growth. Several competition indices including stand basal area (BA, the sum of stem diameter at breast height (SDBH, and density (N for the broadleaf and coniferous species, as well as similar indices considering only trees with diameters greater than each subject (BAGR, SDBHGR, and NGR, were evaluated. We used a nonlinear mixed model to characterize the basal area increment over the past 5, 10, 15, 20, 25, 30, and 35 years as a function of growth of nearby dominant trees, the size of the subject trees, deciduous and coniferous competition indices, and ecoregions. SDBHGR and BAGR were better predictors for spruce, and SDBHGR and NGR were better for aspen, respectively, than other indices. Results showed strongest correlations with long-term stem growth, as the best models integrated growth for 10-25 years for aspen and ≥ 25 for spruce. Our model demonstrated a remarkable capability (adjusted R(2>0.67 to represent this complex variation in growth as a function of site, size and competition.

  14. Assessing Site Availability of Aspen and Northern Hardwoods for Potential Feedstock Development in Michigan: A Case Study

    Directory of Open Access Journals (Sweden)

    Sara Alian

    2015-05-01

    Full Text Available The importance of wood and wood byproducts as biomass feedstocks is of increasing interest as a source of ethanol and electricity. Second generation woody feedstock sources in Michigan, e.g., hybrid poplar and hybrid willow (Populus spp., and native forests, particularly aspen and northern hardwoods, are a potential source of woody biomass for these uses. This study provides a geographic information system (GIS framework for assessing the current spatial extent of aspen and northern hardwoods and their proximity to roads. Additionally, the potential for expanding the area of these feedstock sources based on pre-European settlement vegetation cover is assessed. Utilizing GIS technology to compile, edit and analyze available geospatial data (e.g., present day and pre-European settlement land use/cover, soils, road infrastructure, and land ownership for counties located in the eastern half of the Upper Peninsula and northern half of the Lower Peninsula of Michigan provides a robust framework for various management scenarios to be evaluated in a cost effective manner and foster better decision making.

  15. Long-term exposure to elevated CO2 and O3 alters aspen foliar chemistry across developmental stages.

    Science.gov (United States)

    Couture, J J; Holeski, L M; Lindroth, R L

    2014-03-01

    Anthropogenic activities are altering levels of greenhouse gases to the extent that multiple and diverse ecosystem processes are being affected. Two gases that substantially influence forest health are atmospheric carbon dioxide (CO2 ) and tropospheric ozone (O3 ). Plant chemistry will play an important role in regulating ecosystem processes in future environments, but little information exists about the longitudinal effects of elevated CO2 and O3 on phytochemistry, especially for long-lived species such as trees. To address this need, we analysed foliar chemical data from two genotypes of trembling aspen, Populus tremuloides, collected over 10 years of exposure to levels of CO2 and O3 predicted for the year 2050. Elevated CO2 and O3 altered both primary and secondary chemistry, and the magnitude and direction of the responses varied across developmental stages and between aspen genotypes. Our findings suggest that the effects of CO2 and O3 on phytochemical traits that influence forest processes will vary over tree developmental stages, highlighting the need to continue long-term, experimental atmospheric change research.

  16. Modelling growth-competition relationships in trembling aspen and white spruce mixed boreal forests of Western Canada.

    Science.gov (United States)

    Huang, Jian-Guo; Stadt, Kenneth J; Dawson, Andria; Comeau, Philip G

    2013-01-01

    We examined the effect of competition on stem growth of Picea glauca and Populus tremuloides in boreal mixedwood stands during the stem exclusion stage. We combined traditional approaches of collecting competition data with dendrochronology to provide retrospective measurements of stem diameter growth. Several competition indices including stand basal area (BA), the sum of stem diameter at breast height (SDBH), and density (N) for the broadleaf and coniferous species, as well as similar indices considering only trees with diameters greater than each subject (BAGR, SDBHGR, and NGR), were evaluated. We used a nonlinear mixed model to characterize the basal area increment over the past 5, 10, 15, 20, 25, 30, and 35 years as a function of growth of nearby dominant trees, the size of the subject trees, deciduous and coniferous competition indices, and ecoregions. SDBHGR and BAGR were better predictors for spruce, and SDBHGR and NGR were better for aspen, respectively, than other indices. Results showed strongest correlations with long-term stem growth, as the best models integrated growth for 10-25 years for aspen and ≥ 25 for spruce. Our model demonstrated a remarkable capability (adjusted R(2)>0.67) to represent this complex variation in growth as a function of site, size and competition.

  17. Protease gene families in Populus and Arabidopsis

    Directory of Open Access Journals (Sweden)

    Jansson Stefan

    2006-12-01

    Full Text Available Abstract Background Proteases play key roles in plants, maintaining strict protein quality control and degrading specific sets of proteins in response to diverse environmental and developmental stimuli. Similarities and differences between the proteases expressed in different species may give valuable insights into their physiological roles and evolution. Results We have performed a comparative analysis of protease genes in the two sequenced dicot genomes, Arabidopsis thaliana and Populus trichocarpa by using genes coding for proteases in the MEROPS database 1 for Arabidopsis to identify homologous sequences in Populus. A multigene-based phylogenetic analysis was performed. Most protease families were found to be larger in Populus than in Arabidopsis, reflecting recent genome duplication. Detailed studies on e.g. the DegP, Clp, FtsH, Lon, rhomboid and papain-Like protease families showed the pattern of gene family expansion and gene loss was complex. We finally show that different Populus tissues express unique suites of protease genes and that the mRNA levels of different classes of proteases change along a developmental gradient. Conclusion Recent gene family expansion and contractions have made the Arabidopsis and Populus complements of proteases different and this, together with expression patterns, gives indications about the roles of the individual gene products or groups of proteases.

  18. ASPEN PLUS在化工设计中的应用%ASPEN PLUS Applications in Chemical Design

    Institute of Scientific and Technical Information of China (English)

    陈坚

    2011-01-01

    Using the ASPEN PLUS simulation methanol-water distillation separation,through sensitivity analysis and mapping tools to optimize the design.%使用ASPEN PLUS模拟甲醇一水精馏分离,通过灵敏度分析和绘图工具优化设计。

  19. Epigenomics of Development in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, Steve; Freitag, Michael; Mockler, Todd

    2013-01-10

    We conducted research to determine the role of epigenetic modifications during tree development using poplar (Populus trichocarpa), a model woody feedstock species. Using methylated DNA immunoprecipitation (MeDIP) or chromatin immunoprecipitation (ChIP), followed by high-throughput sequencing, we are analyzed DNA and histone methylation patterns in the P. trichocarpa genome in relation to four biological processes: bud dormancy and release, mature organ maintenance, in vitro organogenesis, and methylation suppression. Our project is now completed. We have 1) produced 22 transgenic events for a gene involved in DNA methylation suppression and studied its phenotypic consequences; 2) completed sequencing of methylated DNA from eleven target tissues in wildtype P. trichocarpa; 3) updated our customized poplar genome browser using the open-source software tools (2.13) and (V2.2) of the P. trichocarpa genome; 4) produced summary data for genome methylation in P. trichocarpa, including distribution of methylation across chromosomes and in and around genes; 5) employed bioinformatic and statistical methods to analyze differences in methylation patterns among tissue types; and 6) used bisulfite sequencing of selected target genes to confirm bioinformatics and sequencing results, and gain a higher-resolution view of methylation at selected genes 7) compared methylation patterns to expression using available microarray data. Our main findings of biological significance are the identification of extensive regions of the genome that display developmental variation in DNA methylation; highly distinctive gene-associated methylation profiles in reproductive tissues, particularly male catkins; a strong whole genome/all tissue inverse association of methylation at gene bodies and promoters with gene expression; a lack of evidence that tissue specificity of gene expression is associated with gene methylation; and evidence that genome methylation is a significant impediment to tissue

  20. The sucrose transporter family in Populus: the importance of a tonoplast PtaSUT4 to biomass and carbon partitioning.

    Science.gov (United States)

    Payyavula, Raja S; Tay, Kate H C; Tsai, Chung-Jui; Harding, Scott A

    2011-03-01

    Plasma membrane, proton-coupled Group II sucrose symporters (SUT) mediate apoplastic phloem loading and sucrose efflux from source leaves in Arabidopsis and agricultural crop species that have been studied to date. We now report that the most abundantly expressed SUT isoform in Populus tremula×alba, PtaSUT4, is a tonoplast (Group IV) symporter. PtaSUT4 transcripts were readily detected in conducting as well as mesophyll cells in stems and source leaves. In comparison, Group II orthologs PtaSUT1 and PtaSUT3 were very weakly expressed in leaves. Both Group II and Group IV SUT genes were expressed in secondary stem xylem of Populus. Transgenic poplars with RNAi-suppressed PtaSUT4 exhibited increased leaf-to-stem biomass ratios, elevated sucrose content in source leaves and stems, and altered phenylpropanoid metabolism. Transcript abundance of several carbohydrate-active enzymes and phenylalanine ammonia-lyases was also altered in transgenic source leaves. Nitrogen-limitation led to a down-regulation of vacuolar invertases in all plants, which resulted in an augmentation of sucrose pooling and hexose depletion in source leaves and secondary xylem of the transgenic plants. These results are consistent with a major role for PtaSUT4 in orchestrating the intracellular partitioning, and consequently, the efflux of sucrose from source leaves and the utilization of sucrose by lateral and terminal sinks. Our findings also support the idea that PtaSUT4 modulates sucrose efflux and utilization in concert with plant N-status.

  1. The genome of black cottonwood, Populus trichocarpa (Torr.&Gray)

    Energy Technology Data Exchange (ETDEWEB)

    Tuskan, G.A.; DiFazio, S.; Jansson, S.; Bohlmann, J.; Grigoriev,I.; Hellsten, U.; Putnam, N.; Ralph, S.; Rombauts, S.; Salamov, A.; Schein, J.; Sterck, L.; Aerts, A.; Bhalerao, R.R.; Bhalerao, R.P.; Blaudez, D.; Boerjan, W.; Brun, A.; Brunner, A.; Busov, V.; Campbell, M.; Carlson, J.; Chalot, M.; Chapman, J.; Chen, G.-L.; Cooper, D.; Coutinho,P.M.; Couturier, J.; Covert, S.; Cronk, Q.; Cunningham, R.; Davis, J.; Degroeve, S.; Dejardin, A.; dePamphillis, C.; Detter, J.; Dirks, B.; Dubchak, I.; Duplessis, S.; Ehiting, J.; Ellis, B.; Gendler, K.; Goodstein, D.; Gribskov, M.; Grimwood, J.; Groover, A.; Gunter, L.; Hamberger, B.; Heinze, B.; Helariutta, Y.; Henrissat, B.; Holligan, D.; Holt, R.; Huang, W.; Islam-Faridi, N.; Jones, S.; Jones-Rhoades, M.; Jorgensen, R.; Joshi, C.; Kangasjarvi, J.; Karlsson, J.; Kelleher, C.; Kirkpatrick, R.; Kirst, M.; Kohler, A.; Kalluri, U.; Larimer, F.; Leebens-Mack, J.; Leple, J.-C.; Locascio, P.; Lou, Y.; Lucas, S.; Martin,F.; Montanini, B.; Napoli, C.; Nelson, D.R.; Nelson, D.; Nieminen, K.; Nilsson, O.; Peter, G.; Philippe, R.; Pilate, G.; Poliakov, A.; Razumovskaya, J.; Richardson, P.; Rinaldi, C.; Ritland, K.; Rouze, P.; Ryaboy, D.; Schmutz, J.; Schrader, J.; Segerman, B.; Shin, H.; Siddiqui,A.; Sterky, F.; Terry, A.; Tsai, C.; Uberbacher, E.; Unneberg, P.; Vahala, J.; Wall, K.; Wessler, S.; Yang, G.; Yin, T.; Douglas, C.; Marra,M.; Sandberg, G.; Van der Peer, Y.; Rokhsar, D.

    2006-09-01

    We report the draft genome of the black cottonwood tree, Populus trichocarpa. Integration of shotgun sequence assembly with genetic mapping enabled chromosome-scale reconstruction of the genome. Over 45,000 putative protein-coding genes were identified. Analysis of the assembled genome revealed a whole-genome duplication event, with approximately 8,000 pairs of duplicated genes from that event surviving in the Populus genome. A second, older duplication event is indistinguishably coincident with the divergence of the Populus and Arabidopsis lineages. Nucleotide substitution, tandem gene duplication and gross chromosomal rearrangement appear to proceed substantially slower in Populus relative to Arabidopsis. Populus has more protein-coding genes than Arabidopsis, ranging on average between 1.4-1.6 putative Populus homologs for each Arabidopsis gene. However, the relative frequency of protein domains in the two genomes is similar. Overrepresented exceptions in Populus include genes associated with disease resistance, meristem development, metabolite transport and lignocellulosic wall biosynthesis.

  2. Influence of stocking, site quality, stand age, low-severity canopy disturbance, and forest composition on sub-boreal aspen mixedwood carbon stocks

    Science.gov (United States)

    Reinikainen, Michael; D’Amato, Anthony W.; Bradford, John B.; Fraver, Shawn

    2014-01-01

    Low-severity canopy disturbance presumably influences forest carbon dynamics during the course of stand development, yet the topic has received relatively little attention. This is surprising because of the frequent occurrence of such events and the potential for both the severity and frequency of disturbances to increase as a result of climate change. We investigated the impacts of low-severity canopy disturbance and average insect defoliation on forest carbon stocks and rates of carbon sequestration in mature aspen mixedwood forests of varying stand age (ranging from 61 to 85 years), overstory composition, stocking level, and site quality. Stocking level and site quality positively affected the average annual aboveground tree carbon increment (CAAI), while stocking level, site quality, and stand age positively affected tree carbon stocks (CTREE) and total ecosystem carbon stocks (CTOTAL). Cumulative canopy disturbance (DIST) was reconstructed using dendroecological methods over a 29-year period. DIST was negatively and significantly related to soil carbon (CSOIL), and it was negatively, albeit marginally, related to CTOTAL. Minima in the annual aboveground carbon increment of trees (CAI) occurred at sites during defoliation of aspen (Populus tremuloides Michx.) by forest tent caterpillar (Malacosoma disstria Hubner), and minima were more extreme at sites dominated by trembling aspen than sites mixed with conifers. At sites defoliated by forest tent caterpillar in the early 2000s, increased sequestration by the softwood component (Abies balsamea (L.) Mill. and Picea glauca (Moench) Voss) compensated for overall decreases in CAI by 17% on average. These results underscore the importance of accounting for low-severity canopy disturbance events when developing regional forest carbon models and argue for the restoration and maintenance of historically important conifer species within aspen mixedwoods to enhance stand-level resilience to disturbance agents and maintain

  3. The Populus superoxide dismutase gene family and its responses to drought stress in transgenic poplar overexpressing a pine cytosolic glutamine synthetase (GS1a.

    Directory of Open Access Journals (Sweden)

    Juan Jesús Molina-Rueda

    Full Text Available BACKGROUND: Glutamine synthetase (GS plays a central role in plant nitrogen assimilation, a process intimately linked to soil water availability. We previously showed that hybrid poplar (Populus tremula X alba, INRA 717-1B4 expressing ectopically a pine cytosolic glutamine synthetase gene (GS1a display enhanced tolerance to drought. Preliminary transcriptome profiling revealed that during drought, members of the superoxide dismutase (SOD family were reciprocally regulated in GS poplar when compared with the wild-type control, in all tissues examined. SOD was the only gene family found to exhibit such patterns. RESULTS: In silico analysis of the Populus genome identified 12 SOD genes and two genes encoding copper chaperones for SOD (CCSs. The poplar SODs form three phylogenetic clusters in accordance with their distinct metal co-factor requirements and gene structure. Nearly all poplar SODs and CCSs are present in duplicate derived from whole genome duplication, in sharp contrast to their predominantly single-copy Arabidopsis orthologs. Drought stress triggered plant-wide down-regulation of the plastidic copper SODs (CSDs, with concomitant up-regulation of plastidic iron SODs (FSDs in GS poplar relative to the wild type; this was confirmed at the activity level. We also found evidence for coordinated down-regulation of other copper proteins, including plastidic CCSs and polyphenol oxidases, in GS poplar under drought conditions. CONCLUSIONS: Both gene duplication and expression divergence have contributed to the expansion and transcriptional diversity of the Populus SOD/CCS families. Coordinated down-regulation of major copper proteins in drought-tolerant GS poplars supports the copper cofactor economy model where copper supply is preferentially allocated for plastocyanins to sustain photosynthesis during drought. Our results also extend previous findings on the compensatory regulation between chloroplastic CSDs and FSDs, and suggest that this

  4. Dependence of Photosynthetic Capacity, Photosynthetic Pigment Allocation, and Carbon Storage on Nitrogen Levels in Foliage of Aspen Stands

    Science.gov (United States)

    Middleton, Elizabeth M.; Sullivan, Joseph H.; Papagno, Andrea J.

    2000-01-01

    The role of foliar nitrogen (N) in the seasonal dynamics and vertical canopy distribution of photosynthetic pigments, photosynthetic capacity, and carbon (C) storage was investigated in boreal broadleaved species. The study was conducted at two different aged stands (60 y and 15 y) in 1994 and 1996 in Saskatchewan, Canada as part of the Boreal Ecosystem-Atmosphere Study (BOREAS). Foliage in upper and lower strata was examined for aspen (Populus tremuloides Michx.) and its associated hazelnut shrub (Corylus americana Walt.). We determined that C accumulation, expressed as dry mass per unit leaf area (mg C cm (exp -2)), was linearly dependent on N content (approximately 0.3- 3.5 mg N cm (exp -2))(r (exp 2) = 0.93, n=383, P less than 0.001) when eleven foliage groups were defined according to species, site, and developmental stage. C assembly was greatest in the upper aspen strata of both sites (seasonal average, 40.1 plus or minus 0.6 mg C cm (exp -2)), intermediate in the lower aspen strata (32.7 plus or minus 0.6), and considerably lower, and similar, in the hazelnut shrub layers (23.7 plus or minus 0.6) and in expanding aspen leaves (23.8 plus or minus 0.5); the lowest C assembly per unit N occurred in the two youngest, emerging leaf groups (17.1 plus or minus 0.6). Other relationships among physiological and biochemical variables were typically non-linear and were confounded by inclusion of the three groups of young (i.e., emerging or expanding) leaves, unless these were separately identified. Net C uptake, measured as photosynthetic capacity (A (sub max), micromole CO2 m (exp -2) s (exp -1)), was greater in aspen throughout the season, and optimal in mid-summer at a C:N ratio of approximately 18 (approximately 2.3 %N). When young leaves were excluded and logarithms of both variables were used, A (sub max) was approximately linearly dependent on N (mg N cm (exp-2) (r (exp 2) = 0.85, n= 193, P less than 0.001), attributed to incorporation of N into photosynthetic

  5. The Application of Aspen Plus Simulation in Coal Gasification%Aspen Plus在煤气化中的应用

    Institute of Scientific and Technical Information of China (English)

    刘晓花; 刘丹; 郝婷; 靳皎; 杨会民; 刘巧霞

    2016-01-01

    Aspen Plus是一种基于稳态化工模拟、优化、灵敏度分析和经济评价的大型化工流程模拟软件,由于其优良的性能而被广泛应用于化工领域.文章主要介绍了Aspen Plus软件的特点,并且综述了近几年来Aspen Plus在煤气化领域中的研究成果和发展概况.

  6. Biomass production in forest plantations used as raw material for industry and energy. Final report. Biomasseproduktion in forstlichen Plantagen fuer die Rohstoff- und Energiegewinnung. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Ahuja, M.R.; Muhs, H.J.

    1986-10-01

    European aspen (Populus tremula), quaking aspen (Populus tremuloides), and their hybrids (hybrid aspen) are short-rotation, fast growing forest tree species, that apparently hold potential for biomass and energy production. Because of inherent difficulties in vegetative propagation in aspen, it has not been possible to propagate selected aspen and hybrid aspen tress on a large scale. Therefore, the aim of this project was to develop unconventional methods of vegetative propagation in aspen that can easily be adapted to nursery practices and are also cost-effective. Explants from buds, leaves, stems, and roots were cultured on a modified Woody Plant Medium for the purposes of microvegetative propagation. Protoplasts were also cultured for regenerative studies. Mainly the bud explants were employed for microvegetative propagation. A 2-step micropropagation method, which is commmercially feasible, has been developed for aspen. This method involves: (1) culture of bud explants on a medium for bud conditioning and microshoot proliferation, and (2) rooting of microshoots in peat-perlite mix. By employing this 2-step micropropagation method, several thousand plants have been regenerated from about 50 mature selected aspen and hybrid aspen trees ranging from 1 to 40 years of age. Following transfer to field conditions, tissue culture derived plants exhibited vigorous growth and attained a height of 1.5-2 meters in the first growing season. (orig.) With 23 refs., 1 tab., 20 figs.

  7. Barcoding poplars (Populus L. from western China.

    Directory of Open Access Journals (Sweden)

    Jianju Feng

    Full Text Available BACKGROUND: Populus is an ecologically and economically important genus of trees, but distinguishing between wild species is relatively difficult due to extensive interspecific hybridization and introgression, and the high level of intraspecific morphological variation. The DNA barcoding approach is a potential solution to this problem. METHODOLOGY/PRINCIPAL FINDINGS: Here, we tested the discrimination power of five chloroplast barcodes and one nuclear barcode (ITS among 95 trees that represent 21 Populus species from western China. Among all single barcode candidates, the discrimination power is highest for the nuclear ITS, progressively lower for chloroplast barcodes matK (M, trnG-psbK (G and psbK-psbI (P, and trnH-psbA (H and rbcL (R; the discrimination efficiency of the nuclear ITS (I is also higher than any two-, three-, or even the five-locus combination of chloroplast barcodes. Among the five combinations of a single chloroplast barcode plus the nuclear ITS, H+I and P+I differentiated the highest and lowest portion of species, respectively. The highest discrimination rate for the barcodes or barcode combinations examined here is 55.0% (H+I, and usually discrimination failures occurred among species from sympatric or parapatric areas. CONCLUSIONS/SIGNIFICANCE: In this case study, we showed that when discriminating Populus species from western China, the nuclear ITS region represents a more promising barcode than any maternally inherited chloroplast region or combination of chloroplast regions. Meanwhile, combining the ITS region with chloroplast regions may improve the barcoding success rate and assist in detecting recent interspecific hybridizations. Failure to discriminate among several groups of Populus species from sympatric or parapatric areas may have been the result of incomplete lineage sorting, frequent interspecific hybridizations and introgressions. We agree with a previous proposal for constructing a tiered barcoding system in

  8. Terra Populus and DataNet Collaboration

    Science.gov (United States)

    Kugler, T.; Ruggles, S.; Fitch, C. A.; Clark, P. D.; Sobek, M.; Van Riper, D.

    2012-12-01

    Terra Populus, part of NSF's new DataNet initiative, is developing organizational and technical infrastructure to integrate, preserve, and disseminate data describing changes in the human population and environment over time. Terra Populus will incorporate large microdata and aggregate census datasets from the United States and around the world, as well as land use, land cover, climate and other environmental datasets. These data are widely dispersed, exist in a variety of data structures, have incompatible or inadequate metadata, and have incompatible geographic identifiers. Terra Populus is developing methods of integrating data from different domains and translating across data structures based on spatio-temporal linkages among data contents. The new infrastructure will enable researchers to identify and merge data from heterogeneous sources to study the relationships between human behavior and the natural world. Terra Populus will partner with data archives, data producers, and data users to create a sustainable international organization that will guarantee preservation and access over multiple decades. Terra Populus is also collaborating with the other projects in the DataNet initiative - DataONE, the DataNet Federation Consortium (DFC) and Sustainable Environment-Actionable Data (SEAD). Taken together, the four projects address aspects of the entire data lifecycle, including planning, collection, documentation, discovery, integration, curation, preservation, and collaboration; and encompass a wide range of disciplines including earth sciences, ecology, social sciences, hydrology, oceanography, and engineering. The four projects are pursuing activities to share data, tools, and expertise between pairs of projects as well as collaborating across the DataNet program on issues of cyberinfrastructure and community engagement. Topics to be addressed through program-wide collaboration include technical, organizational, and financial sustainability; semantic

  9. Aspen Grupp võitis RKASi / Lemmi Kann

    Index Scriptorium Estoniae

    Kann, Lemmi

    2008-01-01

    Ehitusfirma Aspen Grupp OÜ võitis Tallinna ringkonnakohtus Riigi Kinnisvara AS-i, kes diskvalifitseeris ehitusfirma riigihankelt seaduses olnud maksevõlgnevuse keelu tõttu. Vt. samas: Lahendust ootavad veel kaks kohtuasja

  10. Long-term monitoring of western aspen--lessons learned.

    Science.gov (United States)

    Strand, E K; Bunting, S C; Starcevich, L A; Nahorniak, M T; Dicus, G; Garrett, L K

    2015-08-01

    Aspen woodland is an important ecosystem in the western United States. Aspen is currently declining in western mountains; stressors include conifer expansion due to fire suppression, drought, disease, heavy wildlife and livestock use, and human development. Forecasting of tree species distributions under future climate scenarios predicts severe losses of western aspen within the next 50 years. As a result, aspen has been selected as one of 14 vital signs for long-term monitoring by the National Park Service Upper Columbia Basin Network. This article describes the development of a monitoring protocol for aspen including inventory mapping, selection of sampling locations, statistical considerations, a method for accounting for spatial dependence, field sampling strategies, and data management. We emphasize the importance of collecting pilot data for use in statistical power analysis and semi-variogram analysis prior to protocol implementation. Given the spatial and temporal variability within aspen stem size classes, we recommend implementing permanent plots that are distributed spatially within and among stands. Because of our careful statistical design, we were able to detect change between sampling periods with desired confidence and power. Engaging a protocol development and implementation team with necessary and complementary knowledge and skills is critical for success. Besides the project leader, we engaged field sampling personnel, GIS specialists, statisticians, and a data management specialist. We underline the importance of frequent communication with park personnel and network coordinators.

  11. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

    OpenAIRE

    Labbé, Jessy L.; Weston, David J; Nora eDunkirk; Pelletier, Dale A.; Tuskan, Gerald A.

    2014-01-01

    Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing colle...

  12. Aspen Global Change Institute Summer Science Sessions

    Energy Technology Data Exchange (ETDEWEB)

    Katzenberger, John; Kaye, Jack A

    2006-10-01

    The Aspen Global Change Institute (AGCI) successfully organized and convened six interdisciplinary meetings over the course of award NNG04GA21G. The topics of the meetings were consistent with a range of issues, goals and objectives as described within the NASA Earth Science Enterprise Strategic Plan and more broadly by the US Global Change Research Program/Our Changing Planet, the more recent Climate Change Program Strategic Plan and the NSF Pathways report. The meetings were chaired by two or more leaders from within the disciplinary focus of each session. 222 scholars for a total of 1097 participants-days were convened under the auspices of this award. The overall goal of each AGCI session is to further the understanding of Earth system science and global environmental change through interdisciplinary dialog. The format and structure of the meetings allows for presentation by each participant, in-depth discussion by the whole group, and smaller working group and synthesis activities. The size of the group is important in terms of the group dynamics and interaction, and the ability for each participant's work to be adequately presented and discussed within the duration of the meeting, while still allowing time for synthesis

  13. Spring leaf flush in aspen (Populus tremuloides) clones is altered by growth at elevated carbon dioxide and elevated ozone

    Science.gov (United States)

    Early spring leaf out is important to the success of trees competing for light and space in dense forest plantation canopies. In this study, we investigated spring leaf flush and how elevated carbon dioxide concentration and elevated ozone concentration altered leaf area index development in a clos...

  14. Aspen Plus功能扩展方法探讨%Discussions on Method of Function Development for Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    原璐; 吕海霞; 项曙光

    2005-01-01

    对化工过程模拟软件Aspen Plus的用户模型的开发进行了分析,探讨了Aspen Plus用户模型开发步骤和编写方法.Aspen Plus支持6种用户模型,其编写除了要遵循一个通用的规则外,针对每一种用户模型又有不同的定义方式.用户模型的编译和连接通过Aspen Plus提供的编译程序aspcomp和asplink来完成,最终生成一个目标模块文件或动态连接库.将该目标模块文件或动态连接库复制到Aspen Plus的执行目录下,即完成一个用户模型的开发全过程.最后给出一个具体用户模型的例子,以帮助用户熟悉该方法.

  15. Wood Pyrolysis Using Aspen Plus Simulation and Industrially Applicable Model

    Directory of Open Access Journals (Sweden)

    Lestinsky Pavel

    2016-03-01

    Full Text Available Over the past decades, a great deal of experimental work has been carried out on the development of pyrolysis processes for wood and waste materials. Pyrolysis is an important phenomenon in thermal treatment of wood, therefore, the successful modelling of pyrolysis to predict the rate of volatile evolution is also of great importance. Pyrolysis experiments of waste spruce sawdust were carried out. During the experiment, gaseous products were analysed to determine a change in the gas composition with increasing temperature. Furthermore, the model of pyrolysis was created using Aspen Plus software. Aspects of pyrolysis are discussed with a description of how various temperatures affect the overall reaction rate and the yield of volatile components. The pyrolysis Aspen plus model was compared with the experimental data. It was discovered that the Aspen Plus model, being used by several authors, is not good enough for pyrolysis process description, but it can be used for gasification modelling.

  16. PERACETIC ACID PRETREATMENT OF ALFALFA STEM AND ASPEN BIOMASS

    OpenAIRE

    Lei Xu; Ulrike W. Tschirner

    2011-01-01

    Alfalfa stems and ground aspen were exposed to peracetic acid (0.5 to 9% on biomass) at temperatures ranging from 40 to 100° C and reaction times from 1 to 5 hours. Glucose release as a percentage of total cellulose content was determined using subsequent standard enzymatic hydrolysis. Statistical analysis confirmed that aspen showed a strong response to peracetic acid addition rate. 9% peracetic acid removed 14% of the original lignin and increased the rate of glucose release from 23% to 44%...

  17. Ecophysiology of Trembling Aspen in Response to Root-Zone Conditions and Competition on Reclaimed Mine Soil.

    Science.gov (United States)

    Bockstette, S.; Landhäusser, S.; Pinno, B.; Dyck, M. F.

    2014-12-01

    Reclaimed soils are typically characterized by increased bulk densities, penetration resistances and poor soil structure as well as associated problems with hydrology and aeration. As a result, available rooting space for planted tree seedlings is often restricted to a shallow layer of topsoil, which is usually of higher quality and is cultivated prior to planting. This may hinder the development of healthy root systems, thus drastically increasing the risk for plant stress by limiting access to soil resources such as water, nutrients and oxygen. These problems are exacerbated when herbaceous plants compete for the same resources within this limited root-zone. To understand how limited rooting space affects the physiology of young trees, we experimentally manipulated soil conditions and levels of competition at a reclaimed mine site in central Alberta, Canada. The site was characterized by heavily compacted, fine textured subsoil (~2.0 Mg ha-1), capped with 15 cm of topsoil (~1.5 Mg ha-1). In a replicated study (n=6) half the plots were treated with a subsoil plow to a depth of about 60 cm to increase available rooting spece. Subsequently, trembling aspen (Populus tremuloides Michx.) and smooth brome (Bromus inermis L.) were planted to create four vegetation covers: aspen (a), brome (b), aspen + brome (ab) and control (c) (no vegetation). Various soil properties, including texture, bulk density, penetration resistance and water availability, in conjunction with plant parameters such as root and shoot growth, leaf area development, sap flow, and stomatal conductance have since been monitored, both in-situ and through destructive sampling. Our results indicate that the soil treatment was effective in lowering bulk densities and penetration resistance, while improving moisture retention characteristics. Tree seedling growth and leaf area development were significantly greater without competition, but did not differ between soil treatments. The soil treatment generally

  18. Aspen Plus 7.3在精馏设计中的应用%The Application of Aspen Plus 7.3 in Distillation Design

    Institute of Scientific and Technical Information of China (English)

    薛科创; 许航线

    2014-01-01

    Aspen Plus 7.3作为化工设计的首选软件,得到了众多化工爱好者的青睐。以Aspen Plus 7.3在精馏设计中的应用为例,介绍了Aspen Plus 7.3在化工设计中的步骤和方法,为我们进行化工设计和原有工艺改进提供了方法。%Aspen Plus 7.3 as the chemical engineering design software of the first choice have liked by many chemical enthusiasts. This paper shows that Aspen Plus 7.3 in the chemical design steps and methods for us to carry out chemical process design and improvement of existing methods by Aspen Plus 8.0 in distillation design application as an example.

  19. Application of Model Analysis Tools in ASPEN PLUS%ASPEN PLUS模型分析工具的应用

    Institute of Scientific and Technical Information of China (English)

    吴建方

    2011-01-01

    随着计算机技术的发展,ASPENPLUS在化工中的应用越来越广泛,文章对ASPENPLUS模拟软件进行概括,重点论述模型分析工具在化工中的应用。%With the development computer technique,ASPEN PLUS is used more and more widely in the chemical engineering,model analysis tools is mainly discussed in the chemical engineering according to summarizing ASPEN PLUS.

  20. RESTORATION OF QUAKING ASPEN WOODLANDS INVADED BY WESTERN JUNIPER

    Science.gov (United States)

    Quaking aspen woodlands are important plant communities in the interior mountains of the western United States, providing essential habitat for many wildlife species and contain a high diversity of understory plants. Western juniper woodlands are rapidly replacing lower elevation (<6800 ft) quaking...

  1. The 2013 Aspen Prize for Community College Excellence

    Science.gov (United States)

    Perlstein, Linda

    2013-01-01

    For millions of Americans, community colleges provide an essential pathway to well-paying jobs and continuing higher education. The Aspen Prize for Community College Excellence honors those institutions that strive for and achieve exceptional levels of success for all students, while they are in college and after they graduate. Community colleges…

  2. Defining Excellence: Lessons from the 2013 Aspen Prize Finalists

    Science.gov (United States)

    Aspen Institute, 2013

    2013-01-01

    In many respects, one couldn't find a group of 10 schools more diverse than the finalists for the 2013 Aspen Prize for Community College Excellence. One community college serves 1,500 students, another 56,000. There are institutions devoted primarily--even solely--to technical degrees, and ones devoted mainly to preparing students for further…

  3. Identification and Characterization of the Populus AREB/ABF Subfamily

    Institute of Scientific and Technical Information of China (English)

    Lexiang Ji; Jia Wang; Meixia Ye; Ying Li; Bin Guo; Zhong Chen; Hao Li; Xinmin An

    2013-01-01

    Abscisic acid (ABA) is a major plant hormone that plays an important role in responses to abiotic stresses.The ABA-responsive element binding proteinlABRE-binding factor (AREB/ABF) gene subfamily contains crucial transcription factors in the ABA-mediated signaling pathway.In this study,a total of 14 putative AREB/ABF members were identified in the Populus trichocarpa Torr.& Gray.genome using five AREB/ABF amino acid sequences from Arabidopsis thaliana L.as probes.The 14 putative Populus subfamily members showed high protein similarities,especially in the basic leucine zipper (bZlP) domain region.A neighbor-joining analysis combined with gene structure data revealed homology among the 14 genes.The expression patterns of the Populus AREB/ABF subfamily suggested that the most abundant transcripts of 11 genes occurred in leaf tissues,while two genes were most transcribed in root tissues.Significantly,eight Populus AREB/ABF gene members were upregulated after treatment with 100 μM exogenous ABA,while the other six members were downregulated.We identified the expression profiles of the subfamily members in Populus tissues and elucidated different response patterns of Populus AREB/ABF members to ABA stress.This study provided insight into the roles of Populus AREB/ABF homologues in plant response to abiotic stresses.

  4. Orbital Express mission operations planning and resource management using ASPEN

    Science.gov (United States)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Daniel

    2008-04-01

    As satellite equipment and mission operations become more costly, the drive to keep working equipment running with less labor-power rises. Demonstrating the feasibility of autonomous satellite servicing was the main goal behind the Orbital Express (OE) mission. Like a tow-truck delivering gas to a car on the road, the "servicing" satellite of OE had to find the "client" from several kilometers away, connect directly to the client, and transfer fluid (or a battery) autonomously, while on earth-orbit. The mission met 100% of its success criteria, and proved that autonomous satellite servicing is now a reality for space operations. Planning the satellite mission operations for OE required the ability to create a plan which could be executed autonomously over variable conditions. As the constraints for execution could change weekly, daily, and even hourly, the tools used create the mission execution plans needed to be flexible and adaptable to many different kinds of changes. At the same time, the hard constraints of the plans needed to be maintained and satisfied. The Automated Scheduling and Planning Environment (ASPEN) tool, developed at the Jet Propulsion Laboratory, was used to create the schedule of events in each daily plan for the two satellites of the OE mission. This paper presents an introduction to the ASPEN tool, an overview of the constraints of the OE domain, the variable conditions that were presented within the mission, and the solution to operations that ASPEN provided. ASPEN has been used in several other domains, including research rovers, Deep Space Network scheduling research, and in flight operations for the NASA's Earth Observing One mission's EO1 satellite. Related work is discussed, as are the future of ASPEN and the future of autonomous satellite servicing.

  5. Gene Response to Salt Stress in Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Shen Xin; Thomas Teichmenn; Wang Yiqin; Bai Genben; Yu Guangjun; Wang Shasheng

    2003-01-01

    Through construction of a subtracted cDNA library and library screening, a number of salt-induced cDNA fragmentshave been cloned from Populus euphratica. Based on the results of DNA sequencing and Northern analysis, the gene response ofPopulus euphratica to salt stress is discussed. It is indicated that in response to salt treatment the transcription level for some genes ofPopulus euphratica increases by about 1.5 times and significant difference between the responses to osmotic stress and to ion stresshas been observed in gene activity.

  6. aspenONE先进控制和优化集成解决方案

    Institute of Scientific and Technical Information of China (English)

    竺建敏

    2006-01-01

    Aspen DMCplus多变量模型预估先进过程控制系统、Aspen Apollo非线性多变量模型预估先进过程控制系统、Aspen Plus Optimizer闭环实时优化系统、Aspen Blend油品调合多变量先进过程控制与优化系统、Aspen Watch在线监控系统、Aspen IQmodel Powertools软仪表系统,以及Aspen SmartStep智能化的控制器维护系统等构成了AspenTech的aspenONE先进过程控制和优化集成解决方案(见图1)。AspenTech的多变量模型预估控制技术与智能化的控制器维护系统和在线监控系统相结合,

  7. Mission-Driven Media: Not Just Survival, but Success. A Report of the Aspen Institute Forum on Diversity and the Media (Aspen, Colorado, July 11-14, 2001).

    Science.gov (United States)

    Levi, Titus

    This report of the Aspen Institute Forum on Diversity and the Media, supported and funded by the Ford Foundation, is not a typical Aspen Institute forum report. It explores an issue--the sustainability of mission-driven media--and through this discussion becomes a kind of resource guide for managers and others who desire to preserve and promote…

  8. The Application of Aspen Plus Simulation in Fluorine Chemistry%Aspen Plus模拟在氟化工中的应用研究

    Institute of Scientific and Technical Information of China (English)

    李盛姬; 田端正; 吴江平; 张建君

    2011-01-01

    Aspen Plus is a large-scale process simulation system which is used universally in producing equipment design,steady-state simulation and optimization.Many famous engineering and manufacturing companies of chemical engineering,petro-chemical industry and%Aspen Plus是生产装置设计、稳态模拟和优化的大型通用流程模拟系统。全球各大化工、石化、炼油等过程工业制造企业及著名的工程公司都是Aspen Plus的用户。举例介绍了Aspen Plus模拟在氟化工中的应用,分析可能存在的困难,并展望Aspen Plus模拟在氟化工中的应用前景。

  9. Novel cultured protists identify deep-branching environmental DNA clades of cercozoa: New Genera Tremula, Micrometopion, Minimassisteria, Nudifila, Peregrinia.

    Science.gov (United States)

    Howe, Alexis T; Bass, David; Scoble, Josephine M; Lewis, Rhodri; Vickerman, Keith; Arndt, Hartmut; Cavalier-Smith, Thomas

    2011-04-01

    We describe three new orders of filosan Cercozoa, five new deep-branching genera, eight new species of Thaumatomonas, Reckertia, Spongomonas, Rhogostoma, Agitata, Neoheteromita and Paracercomonas, sequence their 18S rDNA, and construct 18S rDNA trees for 148 Cercozoa. Our phylogeny indicates that Filosa were ancestrally gliding flagellates; non-flagellate filose amoebae evolved from them five times independently. The new genera are more closely related to environmental DNA sequences than cultured organisms. Tremula longifila, a zooflagellate glider on both flagella (unlike other Cercozoa), is the most divergent filosan (Tremulida ord. n.). Micrometopion nutans is a eukaryote-eating gliding zooflagellate like Metopion and Metromonas. Minimassisteria diva is a widespread trimorphic marine amoeboflagellate granofilosan. Peregrinia clavideferens, a non-testate, scale-bearing, filose amoeba, branches deeply in Thaumatomonadida, which are probably sisters to Spongomonadida. Nudifila producta is a filose amoeboflagellate related to Clautriavia and Marimonadida (ord. n., e.g. Pseudopirsonia, Auranticordis). We substantially revise Imbricatea, now including Spongomonadida, and Thecofilosea to include Phaeodaria. Thecofilosea and Imbricatea and Thecofilosea are sisters, both arguably ancestrally rigid gliding flagellates with ventral pseudopod-emitting grooves. Scale-free Ovulinata parva is sister to Paulinella, so imbricate silica scales can be lost. Internal hollow silica skeletons evolved twice in Thecofilosea (Ebriida, Phaeodaria) or were multiply lost. Protaspa replaces preoccupied 'Protaspis'.

  10. Stand Composition, Tree Proximity and Size Have Minimal Effects on Leaf Function of Coexisting Aspen and Subalpine Fir.

    Science.gov (United States)

    Rhodes, Aaron C; Barney, Trevor; St Clair, Samuel B

    2016-01-01

    Forest structural heterogeneity due to species composition, spatial relationships and tree size are widely studied patterns in forest systems, but their impacts on tree function are not as well documented. The objective of this study was to examine how stand composition, tree proximity relationships and tree size influence the leaf functional traits of aspen, an early successional species, and subalpine fir, a climax species. We measured foliar nutrients, nonstructural carbohydrates (aspen only), defense chemistry and xylem water potential of aspen and subalpine fir trees in three size classes growing in close proximity or independently from other trees under three stand conditions: aspen dominant, aspen-conifer mixed, and conifer dominant stands. Close proximity of subalpine fir to aspen reduced aspen's storage of starch in foliar tissue by 17% suggesting that competition between these species may have small effects on carbon metabolism in aspen leaves. Simple sugar (glucose + sucrose) concentrations in aspen leaves were slightly higher in larger aspen trees than smaller trees. However, no differences were found in stem water potential, foliar concentrations of nitrogen, phosphorus, or secondary defense chemicals of aspen or subalpine fir across the gradients of stand composition, tree proximity or tree size. These results suggest that mechanisms of coexistence allow both aspen and subalpine fir to maintain leaf function across a wide range of stand structural characteristics. For aspen, resource sharing through its clonal root system and high resource storage capacity may partially contribute to its functional stability in mixed aspen-conifer stands.

  11. Sap flux in pure aspen and mixed aspen-birch forests exposed to elevated concentrations of carbon dioxide and ozone.

    Science.gov (United States)

    Uddling, Johan; Teclaw, Ronald M; Kubiske, Mark E; Pregitzer, Kurt S; Ellsworth, David S

    2008-08-01

    Elevated concentrations of atmospheric carbon dioxide ([CO2]) and tropospheric ozone ([O3]) have the potential to affect tree physiology and structure and hence forest water use, which has implications for climate feedbacks. We investigated how a 40% increase above ambient values in [CO2] and [O3], alone and in combination, affect tree water use of pure aspen and mixed aspen-birch forests in the free air CO2-O3 enrichment experiment near Rhinelander, Wisconsin (Aspen FACE). Measurements of sap flux and canopy leaf area index (L) were made during two growing seasons, when steady-state L had been reached after more than 6 years of exposure to elevated [CO2] and [O3]. Maximum stand-level sap flux was not significantly affected by elevated [O3], but was increased by 18% by elevated [CO2] averaged across years, communities and O(3) regimes. Treatment effects were similar in pure aspen and mixed aspen-birch communities. Increased tree water use in response to elevated [CO2] was related to positive CO2 treatment effects on tree size and L (+40%). Tree water use was not reduced by elevated [O3] despite strong negative O3 treatment effects on tree size and L (-22%). Elevated [O3] predisposed pure aspen stands to drought-induced sap flux reductions, whereas increased tree water use in response to elevated [CO2] did not result in lower soil water content in the upper soil or decreasing sap flux relative to control values during dry periods. Maintenance of soil water content in the upper soil in the elevated [CO2] treatment was at least partly a function of enhanced soil water-holding capacity, probably a result of increased organic matter content from increased litter inputs. Our findings that larger trees growing in elevated [CO2] used more water and that tree size, but not maximal water use, was negatively affected by elevated [O3] suggest that the long-term cumulative effects on stand structure may be more important than the expected primary stomatal closure responses to

  12. A genomics investigation of partitioning into and among flavonoid-derived condensed tannins for carbon sequestration in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Harding, Scott, A; Tsai, Chung-jui; Lindroth, Richard, L

    2013-03-24

    constituted a metabolic carbon drain in developing leaves that was not observed in the roots. We propose that PEA, in addition to other factors, including flavonoid pathway Myb transcription factors, is an important contributor to carbon management and plant defense in Populus. Objective 3: From work related to the first two objectives, it appeared that CT chemistry, at least in terms of the proportions of mono, di and tri hydroxylation at the phenylpropanoid-derived B-ring, changed little if at all when CT accrual per unit time was increased. A large number of transgenic Populus plants with alterations in the expression of flavonoid pathway genes and the potential to produce B-ring, chemically altered CT were generated during the project. Transgenic lines of Populus tremula Michx. Populus alba L. clone 717-1B4, a low CT producer, were produced that over- or under-express several mid and late flavonoid pathway genes including dihydroxyflavonol reductase (DFR-2 isoforms), leucoanthocyanidin reductase (LAR-3 isoforms), anthocyanidin reductase (ANR-2 isoforms), flavonol synthase (FLS-2 isoforms). A large number of additional transformation constructs (chalcone synthases, flavone synthases, and flavanol hydroxylases) were developed that failed to result in transgenic plants. We have purified CT from several of the successful lines and have obtained evidence from pyrolysis GC-MS that CT chemical composition was altered in transgenic lines harboring overexpression constructs for one of the two DFR isoforms. We have also observed increased CT levels in leaves of those lines, but the increases vary substantially in magnitude from experiment to experiment which has led to ongoing efforts to understand the variation before attempting to publish the findings. Preliminary results from some of the transgenic work were presented: An C*, Luo K, El Kayal W, Harding SA, Tsai C-J (2009) Transgenic manipulation of condensed tannins in Populus. IUFRO Tree Biotechnology Conference, Whistler, BC

  13. Analysis of Cryogenic Cycle with Process Modeling Tool: Aspen HYSYS

    Science.gov (United States)

    Joshi, D. M.; Patel, H. K.

    2015-10-01

    Cryogenic engineering deals with the development and improvement of low temperature techniques, processes and equipment. A process simulator such as Aspen HYSYS, for the design, analysis, and optimization of process plants, has features that accommodate the special requirements and therefore can be used to simulate most cryogenic liquefaction and refrigeration processes. Liquefaction is the process of cooling or refrigerating a gas to a temperature below its critical temperature so that liquid can be formed at some suitable pressure which is below the critical pressure. Cryogenic processes require special attention in terms of the integration of various components like heat exchangers, Joule-Thompson Valve, Turbo expander and Compressor. Here, Aspen HYSYS, a process modeling tool, is used to understand the behavior of the complete plant. This paper presents the analysis of an air liquefaction plant based on the Linde cryogenic cycle, performed using the Aspen HYSYS process modeling tool. It covers the technique used to find the optimum values for getting the maximum liquefaction of the plant considering different constraints of other parameters. The analysis result so obtained gives clear idea in deciding various parameter values before implementation of the actual plant in the field. It also gives an idea about the productivity and profitability of the given configuration plant which leads to the design of an efficient productive plant.

  14. PERACETIC ACID PRETREATMENT OF ALFALFA STEM AND ASPEN BIOMASS

    Directory of Open Access Journals (Sweden)

    Lei Xu,

    2011-11-01

    Full Text Available Alfalfa stems and ground aspen were exposed to peracetic acid (0.5 to 9% on biomass at temperatures ranging from 40 to 100° C and reaction times from 1 to 5 hours. Glucose release as a percentage of total cellulose content was determined using subsequent standard enzymatic hydrolysis. Statistical analysis confirmed that aspen showed a strong response to peracetic acid addition rate. 9% peracetic acid removed 14% of the original lignin and increased the rate of glucose release from 23% to 44%. Temperature and reaction time played a less significant role. For alfalfa stems, low levels of peractic acid (0.5% increased glucose release from 30 to 47%. The addition of larger doses of peracetic acid did not show any significant improvement; this effect appears to be closely related to rate of lignin removal. While peracetic acid effectively removed lignin from aspen, 98% of the original lignin was still present in alfalfa after higher level peracetic acid treatments; the yield loss observed during pretreatment of alfalfa stems originates from other biomass components.

  15. Using Aspen plus in thermodynamics instruction a step-by-step guide

    CERN Document Server

    Sandler, Stanley I

    2015-01-01

    A step-by-step guide for students (and faculty) on the use of Aspen in teaching thermodynamics Used for a wide variety of important engineering tasks, Aspen Plus software is a modeling tool used for conceptual design, optimization, and performance monitoring of chemical processes. After more than twenty years, it remains one of the most popular and powerful chemical engineering simulation programs used both industrially and academically. Using Aspen Plus in Thermodynamics Instruction: A Step by Step Guide introduces the reader to the use of Aspen Plus in courses in thermodynamics. It prov

  16. Over-expression of the Hybrid Aspen Homeobox PttKN1 Gene in Red Leaf Beet Induced Altered Coloration of Leaves

    Directory of Open Access Journals (Sweden)

    Quanle XU

    2015-04-01

    Full Text Available PttKN1 (Populus tremula × tremuloides KNOTTED1 gene belongs to the KNOXI gene family. It plays an important role in plant development, typically in meristem initiation, maintenance and organogenesis, and potentially in plant coloration. To investigate the gene functions further, it was introduced into red leaf beet by the floral dip method mediated via Agrobacterium tumefaciens. The transformants demonstrated typical phenotypes as with other PttKN1 transformants. These alterations were very different from the morphology of the wild type. Among them, morphological modification of changed color throughout the entire plant from claret of wild type to yellowish green was the highlight in those transgenic PttKN1-beet plants. The result of spraying selection showed that the PttKN1-beet plants had kanamycin resistance. PCR assay of the 35S-Promoter, NPTII and PttKN1 gene, PCR-Southern analysis of the NPTII and PttKN1 gene showed that the foreign PttKN1 gene had successfully integrated into the genome of beet plant. Furthermore, the results of RT-PCR analysis showed that the gene was ectopic expressed in transgenic plants. These data suggested that there is a correlation between the ectopic expression of PttKN1 gene and morphological alterations of beet plants. Pigment content assay showed that betaxanthins concentrations shared little difference between wild type and transgenic lines, while betacyanins content in transgenic plants was sharply decreased, indicating that the altered plant coloration of the transgenic beet plants may be caused by the changed betacyanins content. The tyrosinase study suggested that the sharply decreased of betacyanins content in transgenic plants was caused via the decreased tyrosinase level. Therefore, the reason for the altered plant coloration may be due to partial inhibition of betacyanin biosynthesis that was induced via the pleiotropic roles of PttKN1 gene.

  17. 2012 Aspen Winter Conferences on High Energy and Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, John; Olivier, Dore; Fox, Patrick; Furic, Ivan; Halkiadakis, Eva; Schmidt, Fabian; Senatore, Leonardo; Smith, Kendrick M; Whiteson, Daniel

    2012-05-01

    Aspen Center for Physics Project Summary DE-SC0007313 Budget Period: 1/1/2012 to 12/31/2012 The Hunt for New Particles, from the Alps to the Plains to the Rockies The 2012 Aspen Winter Conference on Particle Physics was held at the Aspen Center for Physics from February 11 to February 17, 2012. Sixty-seven participants from nine countries, and several universities and national labs attended the workshop titled, The Hunt for New Particles, from the Alps to the Plains to the Rockies. There were 53 formal talks, and a considerable number of informal discussions held during the week. The weeks events included a public lecture-Hunting the Dark Universe given by Neal Weiner from New York University) and attended by 237 members of the public, and a physics cafe geared for high schoolers that is a discussion with physicists conducted by Spencer Chang (University of Oregon), Matthew Reece (Harvard University) and Julia Shelton (Yale University) and attended by 67 locals and visitors. While there were no published proceedings, some of the talks are posted online and can be Googled. The workshop was organized by John Campbell (Fermilab), Patrick Fox (Fermilab), Ivan Furic (University of Florida), Eva Halkiadakis (Rutgers University) and Daniel Whiteson (University of California Irvine). Additional information is available at http://indico.cern.ch/conferenceDisplay.py?confId=143360. Inflationary Theory and its Confrontation with Data in the Planck Era The 2012 Aspen Winter Conference on Astroparticle physics held at the Aspen Center for Physics was Inflationary Theory and its Confrontation with Data in the Planck Era. It was held from January 30 to February 4, 2012. The 62 participants came from 7 countries and attended 43 talks over five days. Late mornings through the afternoon are reserved for informal discussions. In feedback received from participants, it is often these unplanned chats that produce the most excitement due to working through problems with fellow physicists

  18. Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

    Science.gov (United States)

    Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

    2016-06-01

    Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

  19. Rooting greenwood tip cuttings of several Populus clones hydroponically (hydroponic rooting of Populus cuttings)

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, H.M.; Hansen, E.A.; Tolsted, D.N.

    1980-01-01

    Greenwood cuttings of several Populus clones were successfully rooted with a relatively simple hydroponic method. Indolebutyric acid and naphthaleneacetic acid at concentrations of 500 to 5000 ppM applied as a quick dip to the cutting bases, a complete nutrient solution at 20 to 40% of full strength, and a solution temperature between 27 and 30/sup 0/C generally produced the best rooting performance of most clones. Cuttings propagated by the hydroponic procedure rooted faster and generally outgrew those produced by a standard method after being transplanted to pots and grown in the greenhouse.

  20. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus.

    Science.gov (United States)

    Labbé, Jessy L; Weston, David J; Dunkirk, Nora; Pelletier, Dale A; Tuskan, Gerald A

    2014-01-01

    Mycorrhiza helper bacteria (MHB) are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8) from existing collections were included for comparative purposes. We analyzed the effect of co-cultivation of these 23 individual Pseudomonas strains on Laccaria bicolor "S238N" growth rate, mycelial architecture and transcriptional changes. Nineteen of the 23 Pseudomonas strains tested had positive effects on L. bicolor S238N growth, as well as on mycelial architecture, with strains GM41 and GM18 having the most significant effect. Four of seven L. bicolor reporter genes, Tra1, Tectonin2, Gcn5, and Cipc1, thought to be regulated during the interaction with MHB strain BBc6R8, were induced or repressed, while interacting with Pseudomonas strains GM17, GM33, GM41, GM48, Pf-5, and BBc6R8. Strain GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve L. bicolor root colonization on Populus. This tripartite relationship could be exploited for Populus species/genotypes nursery production as a means of improving establishment and survival in marginal lands.

  1. Newly identified helper bacteria stimulate ectomycorrhizal formation in Populus

    Directory of Open Access Journals (Sweden)

    Jessy L Labbé

    2014-10-01

    Full Text Available Mycorrhiza helper bacteria (MHB are known to increase host root colonization by mycorrhizal fungi but the molecular mechanisms and potential tripartite interactions are poorly understood. Through an effort to study Populus microbiome, we isolated 21 Pseudomonas strains from native Populus deltoides roots. These bacterial isolates were characterized and screened for MHB effectiveness on the Populus-Laccaria system. Two additional Pseudomonas strains (i.e., Pf-5 and BBc6R8 from existing collections were included for comparative purposes. We analyzed the effect of co-cultivation of these 23 individual Pseudomonas strains on Laccaria bicolor ‘S238N’ growth rate, mycelial architecture and transcriptional changes. Nineteen of the 23 Pseudomonas strains tested had positive effects on L. bicolor S238N growth, as well as on mycelial architecture, with strains GM41 and GM18 having the most significant effect. Four of seven L. bicolor reporter genes, Tra1, Tectonin2, Gcn5 and Cipc1, thought to be regulated during the interaction with MHB strain BBc6R8, were induced or repressed, while interacting with Pseudomonas strains GM17, GM33, GM41, GM48, Pf-5 and BBc6R8. Strain GM41 promoted the highest roots colonization across three Populus species but most notably in P. deltoides, which is otherwise poorly colonized by L. bicolor. Here we report novel MHB strains isolated from native Populus that improve L. bicolor root colonization on Populus. This tripartite relationship could be exploited for Populus species/genotypes nursery production as a means of improving establishment and survival in marginal lands.

  2. Highly efficient isolation of Populus mesophyll protoplasts and its application in transient expression assays.

    Directory of Open Access Journals (Sweden)

    Jianjun Guo

    Full Text Available BACKGROUND: Populus is a model woody plant and a promising feedstock for lignocellulosic biofuel production. However, its lengthy life cycle impedes rapid characterization of gene function. METHODOLOGY/PRINCIPAL FINDINGS: We optimized a Populus leaf mesophyll protoplast isolation protocol and established a Populus protoplast transient expression system. We demonstrated that Populus protoplasts are able to respond to hormonal stimuli and that a series of organelle markers are correctly localized in the Populus protoplasts. Furthermore, we showed that the Populus protoplast transient expression system is suitable for studying protein-protein interaction, gene activation, and cellular signaling events. CONCLUSIONS/SIGNIFICANCE: This study established a method for efficient isolation of protoplasts from Populus leaf and demonstrated the efficacy of using Populus protoplast transient expression assays as an in vivo system to characterize genes and pathways.

  3. Highly Efficient Isolation of Populus Mesophyll Protoplasts and Its Application in Transient Expression Assays

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jianjun [ORNL; Morrell-Falvey, Jennifer L [ORNL; Labbe, Jessy L [ORNL; Muchero, Wellington [ORNL; Kalluri, Udaya C [ORNL; Tuskan, Gerald A [ORNL; Chen, Jay [ORNL

    2012-01-01

    Background: Populus is a model woody plant and a promising feedstock for lignocellulosic biofuel production. However, its lengthy life cycle impedes rapid characterization of gene function. Methodology/Principal Findings: We optimized a Populus leaf mesophyll protoplast isolation protocol and established a Populus protoplast transient expression system. We demonstrated that Populus protoplasts are able to respond to hormonal stimuli and that a series of organelle markers are correctly localized in the Populus protoplasts. Furthermore, we showed that the Populus protoplast transient expression system is suitable for studying protein-protein interaction, gene activation, and cellular signaling events. Conclusions/Significance: This study established a method for efficient isolation of protoplasts from Populus leaf and demonstrated the efficacy of using Populus protoplast transient expression assays as an in vivo system to characterize genes and pathways.

  4. Aspen Plus在循环冷却水系统中的应用%Application of Aspen Plus in Circulating Cooling Water System

    Institute of Scientific and Technical Information of China (English)

    朱丽华; 李波

    2016-01-01

    Aspen Plus是一个生产装置设计、稳态模拟和优化的大型通用流程模拟系统.基于此,综述Aspen Plus在换热网络中的应用,并且利用Aspen Plus模拟了换热器的换热过程,同时也模拟了污垢对换热器的影响,为优化循环冷却水系统提供了一种新的方法.

  5. Aspen Plus软件在烟气脱硫系统中的应用%Application of Aspen Plus Software in Flue Gas Desulfuration System

    Institute of Scientific and Technical Information of China (English)

    陈茂兵; 缪明烽; 卢作基

    2011-01-01

    介绍了Aspen Plus软件的概况,系统地阐述了Aspen Plus在湿法脱硫工艺系统中应用,详细介绍了Aspen Plus在湿法脱硫FGD系统中的吸收塔、换热器、泵等关键设备设计,开发、选型中的应用,以及模型分析工具在工艺参数优化、降低工程造价中的应用.

  6. Comparative analysis of the transcriptomes of Populus

    Energy Technology Data Exchange (ETDEWEB)

    Tuskan, Gerald A [ORNL; Davis, John M [University of Florida

    2008-01-01

    Sequencing of the Populus trichocarpa genome creates an opportunity to describe the transcriptome of a woody perennial species and establish an atlas of gene expression. A comparison with the transcriptomes of other species can also define genes that are conserved or diverging in plant species. Here, the transcriptome in vegetative organs of the P. trichocarpa reference genotype Nisqually-1 was characterized. A comparison with Arabidopsis thaliana orthologs was used to distinguish gene functional categories that may be evolving differently in a woody perennial and an annual herbaceous species. A core set of genes expressed in common among vegetative organs was detected, as well as organ-specific genes. Statistical tests identified chromatin domains, where adjacent genes were expressed more frequently than expected by chance. Extensive divergence was detected in the expression patterns of A. thaliana and P. trichocarpa orthologs, but transcription of a small number of genes appeared to have remained conserved in the two species. Despite separation of lineages for over 100 million yr, these results suggest that selection has limited transcriptional divergence of genes associated with some essential functions in A. thaliana and P. trichocarpa. However, extensive remodeling of transcriptional networks indicates that expression regulation may be a key determinant of plant diversity.

  7. Variable Nitrogen Fixation in Wild Populus.

    Directory of Open Access Journals (Sweden)

    Sharon L Doty

    Full Text Available The microbiome of plants is diverse, and like that of animals, is important for overall health and nutrient acquisition. In legumes and actinorhizal plants, a portion of essential nitrogen (N is obtained through symbiosis with nodule-inhabiting, N2-fixing microorganisms. However, a variety of non-nodulating plant species can also thrive in natural, low-N settings. Some of these species may rely on endophytes, microorganisms that live within plants, to fix N2 gas into usable forms. Here we report the first direct evidence of N2 fixation in the early successional wild tree, Populus trichocarpa, a non-leguminous tree, from its native riparian habitat. In order to measure N2 fixation, surface-sterilized cuttings of wild poplar were assayed using both 15N2 incorporation and the commonly used acetylene reduction assay. The 15N label was incorporated at high levels in a subset of cuttings, suggesting a high level of N-fixation. Similarly, acetylene was reduced to ethylene in some samples. The microbiota of the cuttings was highly variable, both in numbers of cultured bacteria and in genetic diversity. Our results indicated that associative N2-fixation occurred within wild poplar and that a non-uniformity in the distribution of endophytic bacteria may explain the variability in N-fixation activity. These results point to the need for molecular studies to decipher the required microbial consortia and conditions for effective endophytic N2-fixation in trees.

  8. Growth of Populus and Salix Species under Compost Leachate Irrigation

    Directory of Open Access Journals (Sweden)

    Tooba Abedi

    2014-12-01

    Full Text Available According to the known broad variation in remediation capacity, three plant species were used in the experiment: two fast growing poplar’s clones - Populus deltoides, Populus euramericana, and willows Salix alba. Populus and Salix cuttings were collected from the nursery of the Populus Research Center of Safrabasteh in the eastern part of Guilan province at north of Iran. The Populus clones were chosen because of their high biomass production capacity and willow- because it is native in Iran. The highest diameter growth rate was exhibited for all three plant species by the 1:1 treatment with an average of 0.26, 0.22 and 0.16 cm in eight months period for P. euroamericana, P. deltoides and S. alba, respectively. Over a period of eight months a higher growth rate of height was observed in (P and (1:1 treatment for S. alba (33.70 and 15.77 cm, respectively and in (C treatment for P. deltoides (16.51 cm. P. deltoides and S. alba produced significantly (p<0.05 smaller aboveground biomass in (P treatment compared to all species. P. deltoides exhibited greater mean aboveground biomass in the (1:1 treatment compared to other species. There were significant differences (p<0.05 in the growth of roots between P. deltoides, P. euramericana and S. alba in all of the treatments.

  9. Efficient Agrobacterium-Mediated Transformation of Hybrid Poplar Populus davidiana Dode × Populus bollena Lauche

    Directory of Open Access Journals (Sweden)

    Xue Han

    2013-01-01

    Full Text Available Poplar is a model organism for high in vitro regeneration in woody plants. We have chosen a hybrid poplar Populus davidiana Dode × Populus bollena Lauche. By optimizing the Murashige and Skoog medium with (0.3 mg/L 6-benzylaminopurine and (0.08 mg/L naphthaleneacetic acid, we have achieved the highest frequency (90% for shoot regeneration from poplar leaves. It was also important to improve the transformation efficiency of poplar for genetic breeding and other applications. In this study, we found a significant improvement of the transformation frequency by controlling the leaf age. Transformation efficiency was enhanced by optimizing the Agrobacterium concentration (OD600 = 0.8–1.0 and an infection time (20–30 min. According to transmission electron microscopy observations, there were more Agrobacterium invasions in the 30-day-old leaf explants than in 60-day-old and 90-day-old explants. Using the green fluorescent protein (GFP marker, the expression of MD–GFP fusion proteins in the leaf, shoot, and root of hybrid poplar P. davidiana Dode × P. bollena Lauche was visualized for confirmation of transgene integration. Southern and Northern blot analysis also showed the integration of T-DNA into the genome and gene expression of transgenic plants. Our results suggest that younger leaves had higher transformation efficiency (~30% than older leaves (10%.

  10. Repeated unidirectional introgression towards Populus balsamifera in contact zones of exotic and native poplars

    NARCIS (Netherlands)

    Thompson, S.L.; Lamothe, M.; Meirmans, P.G.; Périnet, P.; Isabel, N.

    2010-01-01

    As the evolutionary significance of hybridization is largely dictated by its extent beyond the first generation, we broadly surveyed patterns of introgression across a sympatric zone of two native poplars (Populus balsamifera, Populus deltoides) in Quebec, Canada within which European exotic Populus

  11. Transition to an IP Environment. A Report of the Annual Aspen Institute Conference on Telecommunications Policy (15th, Aspen, Colorado, August 12-16, 2000) with Thoughts on the Implications of Technological Change for Telecommunications Policy.

    Science.gov (United States)

    Entman, Robert M.; Katz, Michael L.

    The Aspen Institute's Communications and Society Program convened leaders and experts in the telecommunications and related fields to address telecommunications regulation in an IP (Internet Protocols) environment at the 15th annual Aspen Institute Telecommunications Policy Conference (Aspen, Colorado, August 12-16, 2000). The report from this…

  12. Using user models in Matlab® within the Aspen Plus® interface with an Excel® link

    OpenAIRE

    Javier Fontalvo Alzate

    2014-01-01

    Process intensification and new technologies require tools for process design that can be integrated into well-known simulation software, such as Aspen Plus®. Thus, unit operations that are not included in traditional Aspen Plus software packages can be simulated with Matlab® and integrated within the Aspen Plus interface. In this way, the user can take advantage of all of the tools of Aspen Plus, such as optimization, sensitivity analysis and cost estimation. This paper gives a detailed desc...

  13. Reserves accumulated in non-photosynthetic organs during the previous growing season drive plant defenses and growth in aspen in the subsequent growing season.

    Science.gov (United States)

    Najar, Ahmed; Landhäusser, Simon M; Whitehill, Justin G A; Bonello, Pierluigi; Erbilgin, Nadir

    2014-01-01

    Plants store non-structural carbohydrates (NSC), nitrogen (N), as well as other macro and micronutrients, in their stems and roots; the role of these stored reserves in plant growth and defense under herbivory pressure is poorly understood, particularly in trees. Trembling aspen (Populus tremuloides) seedlings with different NSC and N reserves accumulated during the previous growing season were generated in the greenhouse. Based on NSC and N contents, seedlings were assigned to one of three reserve statuses: Low N-Low NSC, High N-Medium NSC, or High N-High NSC. In the subsequent growing season, half of the seedlings in each reserve status was subjected to defoliation by forest tent caterpillar (Malacosoma disstria) while the other half was left untreated. Following defoliation, the effect of reserves was measured on foliar chemistry (N, NSC) and caterpillar performance (larval development). Due to their importance in herbivore feeding, we also quantified concentrations of phenolic glycoside compounds in foliage. Seedlings in Low N-Low NSC reserve status contained higher amounts of induced phenolic glycosides, grew little, and supported fewer caterpillars. In contrast, aspen seedlings in High N-Medium or High NSC reserve statuses contained lower amounts of induced phenolic glycosides, grew faster, and some of the caterpillars which fed on these seedlings developed up to their fourth instar. Furthermore, multiple regression analysis indicated that foliar phenolic glycoside concentration was related to reserve chemistry (NSC, N). Overall, these results demonstrate that reserves accumulated during the previous growing season can influence tree defense and growth in the subsequent growing season. Additionally, our study concluded that the NSC/N ratio of reserves in the previous growing season represents a better measure of resources available for use in defense and growth than the foliar NSC/N ratios.

  14. Simulation of Quaking Aspen Potential Fire Behavior in Northern Utah, USA

    Directory of Open Access Journals (Sweden)

    R. Justin DeRose

    2014-12-01

    Full Text Available Current understanding of aspen fire ecology in western North America includes the paradoxical characterization that aspen-dominated stands, although often regenerated following fire, are “fire-proof”. We tested this idea by predicting potential fire behavior across a gradient of aspen dominance in northern Utah using the Forest Vegetation Simulator and the Fire and Fuels Extension. The wind speeds necessary for crowning (crown-to-crown fire spread and torching (surface to crown fire spread were evaluated to test the hypothesis that predicted fire behavior is influenced by the proportion of aspen in the stand. Results showed a strong effect of species composition on crowning, but only under moderate fire weather, where aspen-dominated stands were unlikely to crown or torch. Although rarely observed in actual fires, conifer-dominated stands were likely to crown but not to torch, an example of “hysteresis” in crown fire behavior. Results support the hypothesis that potential crown fire behavior varies across a gradient of aspen dominance and fire weather, where it was likely under extreme and severe fire weather, and unlikely under moderate and high fire weather. Furthermore, the “fire-proof” nature of aspen stands broke down across the gradient of aspen dominance and fire weather.

  15. Aspen increase soil moisture, nutrients, organic matter and respiration in Rocky Mountain forest communities.

    Science.gov (United States)

    Buck, Joshua R; St Clair, Samuel B

    2012-01-01

    Development and change in forest communities are strongly influenced by plant-soil interactions. The primary objective of this paper was to identify how forest soil characteristics vary along gradients of forest community composition in aspen-conifer forests to better understand the relationship between forest vegetation characteristics and soil processes. The study was conducted on the Fishlake National Forest, Utah, USA. Soil measurements were collected in adjacent forest stands that were characterized as aspen dominated, mixed, conifer dominated or open meadow, which includes the range of vegetation conditions that exist in seral aspen forests. Soil chemistry, moisture content, respiration, and temperature were measured. There was a consistent trend in which aspen stands demonstrated higher mean soil nutrient concentrations than mixed and conifer dominated stands and meadows. Specifically, total N, NO(3) and NH(4) were nearly two-fold higher in soil underneath aspen dominated stands. Soil moisture was significantly higher in aspen stands and meadows in early summer but converged to similar levels as those found in mixed and conifer dominated stands in late summer. Soil respiration was significantly higher in aspen stands than conifer stands or meadows throughout the summer. These results suggest that changes in disturbance regimes or climate scenarios that favor conifer expansion or loss of aspen will decrease soil resource availability, which is likely to have important feedbacks on plant community development.

  16. Differential response of aspen and birch trees to heat stress under elevated carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Darbah, Joseph N.T., E-mail: darbah@ohio.ed [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States); Department of Environmental and Plant Biology, Ohio University, 315 Porter Hall, Athens, OH 45701 (United States); Sharkey, Thomas D. [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 (United States); Calfapietra, Carlo [Institute of Agro-Environmental and Forest Biology (IBAF), National Research Council (CNR), Via Salaria km 29300, 00016 Monterotondo Scalo, Roma (Italy); Karnosky, David F. [School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, MI 49931 (United States)

    2010-04-15

    The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO{sub 2} and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO{sub 2} protected photosynthesis of both species against moderate heat stress. Elevated CO{sub 2} increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36-39 deg. C) decreased all of these parameters in birch regardless of CO{sub 2} treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO{sub 2} were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO{sub 2}. Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms. - We report that elevated CO{sub 2} confers increased thermotolerance on both aspen and birch trees while isoprene production in aspen confers further thermotolerance in aspen.

  17. The Populus Genome Integrative Explorer (PopGenIE): a new resource for exploring the Populus genome.

    Science.gov (United States)

    Sjödin, Andreas; Street, Nathaniel Robert; Sandberg, Göran; Gustafsson, Petter; Jansson, Stefan

    2009-06-01

    Populus has become an important model plant system. However, utilization of the increasingly extensive collection of genetics and genomics data created by the community is currently hindered by the lack of a central resource, such as a model organism database (MOD). Such MODs offer a single entry point to the collection of resources available within a model system, typically including tools for exploring and querying those resources. As a starting point to overcoming the lack of such an MOD for Populus, we present the Populus Genome Integrative Explorer (PopGenIE), an integrated set of tools for exploring the Populus genome and transcriptome. The resource includes genome, synteny and quantitative trait locus (QTL) browsers for exploring genetic data. Expression tools include an electronic fluorescent pictograph (eFP) browser, expression profile plots, co-regulation within collated transcriptomics data sets, and identification of over-represented functional categories and genomic hotspot locations. A number of collated transcriptomics data sets are made available in the eFP browser to facilitate functional exploration of gene function. Additional homology and data extraction tools are provided. PopGenIE significantly increases accessibility to Populus genomics resources and allows exploration of transcriptomics data without the need to learn or understand complex statistical analysis methods. PopGenIE is available at www.popgenie.org or via www.populusgenome.info.

  18. 77 FR 10491 - City of Aspen; Notice of Intent To File License Application, Filing of Pre-Application Document...

    Science.gov (United States)

    2012-02-22

    ... Energy Regulatory Commission City of Aspen; Notice of Intent To File License Application, Filing of Pre....: 13254-002. c. Date Filed: December 12, 2011. d. Submitted By: City of Aspen. e. Name of Project: Castle Creek Hydroelectric Project. f. Location: On Maroon and Castle Creeks near the City of Aspen, in...

  19. Application of Aspen Plus in the Course of Chemical Engineering Principle%Aspen Plus软件在化工原理教学中的应用

    Institute of Scientific and Technical Information of China (English)

    张春勇; 郑纯智; 汪斌; 张国华; 文颖频; 张纪霞

    2010-01-01

    化工原理是一门内容广、实践性强的课程.为了培养学生的工程实践能力,将Aspen Plus软件应用于化工原理教学.介绍了Aspen Plus软件在化工原理教学中的应用,论述了将Aspen Plus软件强大的参数化建模功能应用于教学过程.将Aspen Plus引入到化工原理教学中,有助于学生对化工原理的理解,有助于学生学习兴趣的提高.

  20. Aspen Plus 8.0在精馏设计中的应用%The Application of Aspen Plus 8.0 in Distillation Design

    Institute of Scientific and Technical Information of China (English)

    薛科创; 闫晓前

    2014-01-01

    作为21世纪的化工人才,不但要懂得化工设计,而且要会使用电脑软件进行设计.Aspen Plus作为化工设计的首选软件,尤其是Aspen Plus 8.0以其新特点,得到了众多化工爱好者的青睐.本文以Aspen Plus 8.0在精馏设计中的应用为例,介绍了Aspen Plus 8.0在化工设计中的步骤和方法,为我们进行化工设计和原有工艺改进提供了方法.

  1. Modelling and Simulation of Gas Engines Using Aspen HYSYS

    OpenAIRE

    M. C. Ekwonu; Perry, S.; E. A. Oyedoh

    2013-01-01

    In this paper gas engine model was developed in Aspen HYSYS V7.3 and validated with Waukesha 16V275GL+ gas engine. Fuel flexibility, fuel types and part load performance of the gas engine were investigated. The design variability revealed that the gas engine can operate on poor fuel with low lower heating value (LHV) such as landfill gas, sewage gas and biogas with biogas offering potential integration with bottoming cycles when compared to natural gas. The result of the gas engin...

  2. Modelling and Simulation of Gas Engines Using Aspen HYSYS

    Directory of Open Access Journals (Sweden)

    M. C. Ekwonu

    2013-12-01

    Full Text Available In this paper gas engine model was developed in Aspen HYSYS V7.3 and validated with Waukesha 16V275GL+ gas engine. Fuel flexibility, fuel types and part load performance of the gas engine were investigated. The design variability revealed that the gas engine can operate on poor fuel with low lower heating value (LHV such as landfill gas, sewage gas and biogas with biogas offering potential integration with bottoming cycles when compared to natural gas. The result of the gas engine simulation gave an efficiency 40.7% and power output of 3592kW.

  3. Effect of technological parameters and wood properties on cutting power in plane milling of juvenile poplar wood

    Directory of Open Access Journals (Sweden)

    Barcík Štefan

    2008-10-01

    Full Text Available This paper presents the results of experimental measurements aimed at observing the effect of technological parameters (cutting speed vc and feed speed vf , type of wood (juvenile wood and mature wood andwood species (aspen Populus tremula, L. and hybrid poplar Populus x Euramericana „Serotina“ on cutting power during plane milling of poplar wood. The results showed the reduction of cutting power with the decrease of cutting speed and feed speed. Lower cutting power was also measured in milling hybrid poplar than in milling aspen. The test also confirmed the effect of different anatomical and chemical structure of juvenile wood in relation to mature wood on different physical and mechanical properties of such wood and hence also on the cutting power in processing juvenile wood.

  4. 某化工系统流程的Aspen Plus软件模拟分析%Simulation Analysis with Aspen Plus for a Chemical System Process

    Institute of Scientific and Technical Information of China (English)

    孙立娟; 王佳; 齐鹏

    2015-01-01

    利用Aspen Plus软件对某化工系统流程模拟,并查看各物流结果.应用实例表明,在化工生产中应用Aspen Plus软件可以优化生产,对设备和整套生产装置的操作参数进行模拟,从而实现装置设计优化.

  5. The glutamine synthetase gene family in Populus

    Directory of Open Access Journals (Sweden)

    Cánovas Francisco M

    2011-08-01

    Full Text Available Abstract Background Glutamine synthetase (GS; EC: 6.3.1.2, L-glutamate: ammonia ligase ADP-forming is a key enzyme in ammonium assimilation and metabolism of higher plants. The current work was undertaken to develop a more comprehensive understanding of molecular and biochemical features of GS gene family in poplar, and to characterize the developmental regulation of GS expression in various tissues and at various times during the poplar perennial growth. Results The GS gene family consists of 8 different genes exhibiting all structural and regulatory elements consistent with their roles as functional genes. Our results indicate that the family members are organized in 4 groups of duplicated genes, 3 of which code for cytosolic GS isoforms (GS1 and 1 which codes for the choroplastic GS isoform (GS2. Our analysis shows that Populus trichocarpa is the first plant species in which it was observed the complete GS family duplicated. Detailed expression analyses have revealed specific spatial and seasonal patterns of GS expression in poplar. These data provide insights into the metabolic function of GS isoforms in poplar and pave the way for future functional studies. Conclusions Our data suggest that GS duplicates could have been retained in order to increase the amount of enzyme in a particular cell type. This possibility could contribute to the homeostasis of nitrogen metabolism in functions associated to changes in glutamine-derived metabolic products. The presence of duplicated GS genes in poplar could also contribute to diversification of the enzymatic properties for a particular GS isoform through the assembly of GS polypeptides into homo oligomeric and/or hetero oligomeric holoenzymes in specific cell types.

  6. Evolutionary Quantitative Genomics of Populus trichocarpa.

    Science.gov (United States)

    Porth, Ilga; Klápště, Jaroslav; McKown, Athena D; La Mantia, Jonathan; Guy, Robert D; Ingvarsson, Pär K; Hamelin, Richard; Mansfield, Shawn D; Ehlting, Jürgen; Douglas, Carl J; El-Kassaby, Yousry A

    2015-01-01

    Forest trees generally show high levels of local adaptation and efforts focusing on understanding adaptation to climate will be crucial for species survival and management. Here, we address fundamental questions regarding the molecular basis of adaptation in undomesticated forest tree populations to past climatic environments by employing an integrative quantitative genetics and landscape genomics approach. Using this comprehensive approach, we studied the molecular basis of climate adaptation in 433 Populus trichocarpa (black cottonwood) genotypes originating across western North America. Variation in 74 field-assessed traits (growth, ecophysiology, phenology, leaf stomata, wood, and disease resistance) was investigated for signatures of selection (comparing QST-FST) using clustering of individuals by climate of origin (temperature and precipitation). 29,354 SNPs were investigated employing three different outlier detection methods and marker-inferred relatedness was estimated to obtain the narrow-sense estimate of population differentiation in wild populations. In addition, we compared our results with previously assessed selection of candidate SNPs using the 25 topographical units (drainages) across the P. trichocarpa sampling range as population groupings. Narrow-sense QST for 53% of distinct field traits was significantly divergent from expectations of neutrality (indicating adaptive trait variation); 2,855 SNPs showed signals of diversifying selection and of these, 118 SNPs (within 81 genes) were associated with adaptive traits (based on significant QST). Many SNPs were putatively pleiotropic for functionally uncorrelated adaptive traits, such as autumn phenology, height, and disease resistance. Evolutionary quantitative genomics in P. trichocarpa provides an enhanced understanding regarding the molecular basis of climate-driven selection in forest trees and we highlight that important loci underlying adaptive trait variation also show relationship to climate

  7. Contrasting the patterns of aspen forest and sagebrush shrubland gross ecosystem exchange in montane Idaho, USA

    Science.gov (United States)

    Fellows, A.; Flerchinger, G. N.; Seyfried, M. S.

    2015-12-01

    We investigated the environmental controls on Gross Ecosystem Exchange (GEE) at an aspen forest and a sagebrush shrubland in southwest Idaho. The two sites were situated within a mosaic of vegetation that included temperate deciduous trees, shrublands, and evergreen conifer trees. The distribution of vegetation was presumably linked to water availability; aspen were located in wetter high-elevations sites, topographic drainages, or near snow drifts. Local temperatures have increased by ~2-3 °C over the past 50 years and less precipitation has arrived as snow. These ongoing changes in weather may impact snow water redistribution, plant-water availability, and plant-thermal stress, with associated impacts on vegetation health and production. We used eddy covariance to measure the exchange of water and carbon dioxide above the two sites and partitioned the net carbon flux to determine GEE. The sagebrush record was from 2003-2007 and the aspen record was from 2007-12. The region experienced a modest-to-severe drought in 2007, with ~73% of typical precipitation. We found that aspen were local "hotspots" for carbon exchange; peak rates of aspen GEE were ~ 60% greater than the peak rates of sagebrush GEE. Light, temperature, and water availability were dominant controls on the seasonality of GEE at both sites. Sagebrush and aspen were dormant during winter, limited by cold temperatures during winter and early spring, and water availability during mid-late summer. The onset of summer drought was typically later in the aspen than in the sagebrush. Drifting snow, lateral water redistribution, or increased rooting depths may have increased water availability in the aspen stand. Seasonal patterns of observed soil moisture and evaporation indicated aspen were rooted to >= 1 m. The sagebrush and aspen both responded strongly to the 2007 drought; peak GEE decreased by ~75%, peak GEE shifted to earlier parts of the year, and mid-summer GEE was decreased. We consider potential

  8. Genomics of Secondary Metabolism in Populus: Interactions with Biotic and Abiotic Environments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, F.; Liu, C.; Tschaplinski, T. J.; Zhao, N.

    2009-09-01

    Populus trees face constant challenges from the environment during their life cycle. To ensure their survival and reproduction, Populus trees deploy various types of defenses, one of which is the production of a myriad of secondary metabolites. Compounds derived from the shikimate-phenylpropanoid pathway are the most abundant class of secondary metabolites synthesized in Populus. Among other major classes of secondary metabolites in Populus are terpenoids and fatty acid-derivatives. Some of the secondary metabolites made by Populus trees have been functionally characterized. Some others have been associated with certain biological/ecological processes, such as defense against insects and microbial pathogens or acclimation or adaptation to abiotic stresses. Functions of many Populus secondary metabolites remain unclear. The advent of various novel genomic tools will enable us to explore in greater detail the complexity of secondary metabolism in Populus. Detailed data mining of the Populus genome sequence can unveil candidate genes of secondary metabolism. Metabolomic analysis will continue to identify new metabolites synthesized in Populus. Integrated genomics that combines various 'omics' tools will prove to be the most powerful approach in revealing the molecular and biochemical basis underlying the biosynthesis of secondary metabolites in Populus. Characterization of the biological/ecological functions of secondary metabolites as well as their biosynthesis will provide knowledge and tools for genetically engineering the production of seconday metabolites that can lead to the generation of novel, improved Populus varieties.

  9. Assessment of Populus Wood Chemistry Following the Introduction of a Bt Toxin Gene

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M. F.; Tuskan, G. A.; Payne, P.; Tschaplinski, T. J.; Meilan, R.

    2006-01-01

    Unintended changes in plant physiology, anatomy and metabolism as a result of genetic engineering are a concern as more transgenic plants are commercially deployed in the ecosystem. We compared the cell wall chemical composition of three Populus lines (Populus trichocarpa Torr. and A. Gray x Populus deltoides Bartr. ex Marsh., Populus trichocarpa x Populus nigra L. and Populus deltoides x Populus nigra) genetically modified to express the Cry3A or Cry3B2 protein of Bacillus thuringiensis (Bt) with the cellwall chemistry of non-transformed isogenic control lines. Three genetically modified clones, each represented by 10 independent transgenic lines, were analyzed by pyrolysis molecular beam mass spectrometry, gas chromatography/mass spectrometry and traditional wet chemical analytical methods to assess changes in cell wall composition. Based on the outcome of these techniques, there were no comprehensive differences in chemical composition between the transgenic and control lines for any of the studied clones.

  10. Assessment of Populus wood chemistry following the introduction of a Bt toxin gene

    Energy Technology Data Exchange (ETDEWEB)

    Tschaplinski, Timothy J [ORNL; Davis, M F [National Energy Renewable Laboratory; Tuskan, Gerald A [ORNL; Payne, M M [Boise Cascade LLC; Meilan, R [Purdue University

    2006-01-01

    Unintended changes in plant physiology, anatomy and metabolism as a result of genetic engineering are a concern as more transgenic plants are commercially deployed in the ecosystem. We compared the cell wall chemical composition of three Populus lines (Populus trichocarpa Torr. & A. Gray x Populus trichocarpa Bartr. ex Marsh., Populus trichocarpa x Populus nigra L. and Populus deltoides x Populus nigra) genetically modified to express the Cry3A or Cry3B2 protein of Bacillus thuringiensis (Bt) with the cell wall chemistry of non-transformed isogenic control lines. Three genetically modified clones, each represented by 10 independent transgenic lines, were analyzed by pyrolysis molecular beam mass spectrometry, gas chromatography/mass spectrometry and traditional wet chemical analytical methods to assess changes in cell wall composition. Based on the outcome of these techniques, there were no comprehensive differences in chemical composition between the transgenic and control lines for any of the studied clones.

  11. Aspen shaving versus chip bedding: effects on breeding and behavior.

    Science.gov (United States)

    Jackson, E; Demarest, K; Eckert, W J; Cates-Gatto, C; Nadav, T; Cates, L N; Howard, H; Roberts, A J

    2015-01-01

    The choice of laboratory cage bedding material is often based on both practical and husbandry issues, whereas behavioral outcomes rarely appear to be considered. It has been noted that a breeding success difference appears to be associated with the differential use of aspen chip and aspen shaving bedding in our facility; therefore, we sought to analyze breeding records maintained over a 20-month period. In fact, in all four mouse strains analyzed, shaving bedding was associated with a significant increase in average weanlings per litter relative to chip bedding. To determine whether these bedding types also resulted in differences in behaviors associated with wellbeing, we examined nest building, anxiety-like, depressive-like (or helpless-like), and social behavior in mice housed on chip versus shaving bedding. We found differences in the nests built, but no overall effect of bedding type on the other behaviors examined. Therefore, we argue that breeding success, perhaps especially in more challenging strains, is improved on shaving bedding and this is likely due to improved nest-building potential. For standard laboratory practices, however, these bedding types appear equivalent.

  12. Great Plains ASPEN model development: Phosam section. Final topical report

    Energy Technology Data Exchange (ETDEWEB)

    Stern, S S; Kirman, J J

    1985-02-01

    An ASPEN model has been developed of the PHOSAM Section, Section 4600, of the Great Plains Gasification Plant. The bases for this model are the process description given in Section 6.18 of the Great Plains Project Management Plan and the Lummus Phosam Schematic Process Flow Diagram, Dwg. No. SKD-7102-IM-O. The ASPEN model that has been developed contains the complete set of components that are assumed to be in the gasifier effluent. The model is primarily a flowsheet simulation that will give the material and energy balance and equipment duties for a given set of process conditions. The model is unable to predict fully changes in process conditions that would result from load changes on equipment of fixed sizes, such as a rating model would predict. The model can be used to simulate the steady-state operation of the plant at or near design conditions or to design other PHOSAM units. Because of the limited amount of process information that was available, several major process assumptions had to be made in the development of the flowsheet model. Patent literature was consulted to establish the ammonia concentration in the circulating fluid. Case studies were made with the ammonia content of the feed 25% higher and 25% lower than the base feed. Results of these runs show slightly lower recoveries of ammonia with less ammonia in the feed. As expected, the duties of the Stripper and Fractionator reboilers were higher with more ammonia in the feed. 63 references.

  13. A site dependent top height growth model for hybrid aspen

    Institute of Scientific and Technical Information of China (English)

    Tord Johansson

    2013-01-01

    In this study height growth models for hybrid aspen were developed using three growth equations. The mean age of the hybrid aspen was 21 years (range 15−51 years) with a mean stand density of 946 stems ha-1 (87−2374) and a mean diameter at breast height (over bark) of 19.6 cm (8.5−40.8 cm). Site index was also examined in relation to soil type. Multiple samples were collected for three types of soil: light clay, medium clay and till. Site index curves were constructed using the col-lected data and compared with published reports. A number of dynamic equations were assessed for modeling top-height growth from total age. A Generalized Algebraic Difference Approach model derived by Cieszewski (2001) performed the best. This model explained 99% of the observed variation in tree height growth and exhibited no apparent bias across the range of predicted site indices. There were no significant differences between the soil types and site indices.

  14. A new diterpenoid from the stem bark of Populus davidiana

    Institute of Scientific and Technical Information of China (English)

    Xin Feng Zhang; Xiang Li; Byung Sun Min; Ki Hwan Bae

    2008-01-01

    A new diterpenoid, named populusol A (1), was isolated from the methanolic extraction of the stem bark of Populus davidiana. The structure was elucidated on the basis of extensive 1D and 2D NMR as well as HRFAB-MS spectroscopic analysis.

  15. Auxin-responsive DR5 promoter coupled with transport assays suggest separate but linked routes of auxin transport during woody stem development in Populus.

    Science.gov (United States)

    Spicer, Rachel; Tisdale-Orr, Tracy; Talavera, Christian

    2013-01-01

    Polar auxin transport (PAT) is a major determinant of plant morphology and internal anatomy with important roles in vascular patterning, tropic growth responses, apical dominance and phyllotactic arrangement. Woody plants present a highly complex system of vascular development in which isolated bundles of xylem and phloem gradually unite to form concentric rings of conductive tissue. We generated several transgenic lines of hybrid poplar (Populus tremula x alba) with the auxin-responsive DR5 promoter driving GUS expression in order to visualize an auxin response during the establishment of secondary growth. Distinct GUS expression in the cambial zone and developing xylem-side derivatives supports the current view of this tissue as a major stream of basipetal PAT. However, we also found novel sites of GUS expression in the primary xylem parenchyma lining the outer perimeter of the pith. Strands of primary xylem parenchyma depart the stem as a leaf trace, and showed GUS expression as long as the leaves to which they were connected remained attached (i.e., until just prior to leaf abscission). Tissue composed of primary xylem parenchyma strands contained measurable levels of free indole-3-acetic acid (IAA) and showed basipetal transport of radiolabeled auxin ((3)H-IAA) that was both significantly faster than diffusion and highly sensitive to the PAT inhibitor NPA. Radiolabeled auxin was also able to move between the primary xylem parenchyma in the interior of the stem and the basipetal stream in the cambial zone, an exchange that was likely mediated by ray parenchyma cells. Our results suggest that (a) channeling of leaf-derived IAA first delineates isolated strands of pre-procambial tissue but then later shifts to include basipetal transport through the rapidly expanding xylem elements, and (b) the transition from primary to secondary vascular development is gradual, with an auxin response preceding the appearance of a unified and radially-organized vascular cambium.

  16. Evolutionary Quantitative Genomics of Populus trichocarpa.

    Directory of Open Access Journals (Sweden)

    Ilga Porth

    Full Text Available Forest trees generally show high levels of local adaptation and efforts focusing on understanding adaptation to climate will be crucial for species survival and management. Here, we address fundamental questions regarding the molecular basis of adaptation in undomesticated forest tree populations to past climatic environments by employing an integrative quantitative genetics and landscape genomics approach. Using this comprehensive approach, we studied the molecular basis of climate adaptation in 433 Populus trichocarpa (black cottonwood genotypes originating across western North America. Variation in 74 field-assessed traits (growth, ecophysiology, phenology, leaf stomata, wood, and disease resistance was investigated for signatures of selection (comparing QST-FST using clustering of individuals by climate of origin (temperature and precipitation. 29,354 SNPs were investigated employing three different outlier detection methods and marker-inferred relatedness was estimated to obtain the narrow-sense estimate of population differentiation in wild populations. In addition, we compared our results with previously assessed selection of candidate SNPs using the 25 topographical units (drainages across the P. trichocarpa sampling range as population groupings. Narrow-sense QST for 53% of distinct field traits was significantly divergent from expectations of neutrality (indicating adaptive trait variation; 2,855 SNPs showed signals of diversifying selection and of these, 118 SNPs (within 81 genes were associated with adaptive traits (based on significant QST. Many SNPs were putatively pleiotropic for functionally uncorrelated adaptive traits, such as autumn phenology, height, and disease resistance. Evolutionary quantitative genomics in P. trichocarpa provides an enhanced understanding regarding the molecular basis of climate-driven selection in forest trees and we highlight that important loci underlying adaptive trait variation also show

  17. The Application of Aspen Plus Simulation in Chemical Industry%Aspen Plus在化工中的应用

    Institute of Scientific and Technical Information of China (English)

    张治山; 杨超龙

    2012-01-01

    Aspen Plus是基于稳态化工模拟、优化、灵敏度分析和经济评价的大型化工流程模拟软件,其广泛应用于化学与石油工业、炼油加工、生物及医药等方面。文章介绍了该软件的功能特点,综述了近几年来该流程模拟软件在化工工程中的应用成果及发展情况。%Aspen Plus is based on the steady-state chemical simulation, optimization, sensitivity analysis and economic evaluation of large-scale chemical process simulation software, which is widely used in chemistry and petroleum industry, oil refining process, biology and medicine and so on. The function characteristics of the software were introduced in the paper, the application results and the development situation of chemical process simulation software on process in recent years are summarized.

  18. Establishment of Alleycropped Hybrid Aspen “Crandon” in Central Iowa, USA: Effects of Topographic Position and Fertilizer Rate on Aboveground Biomass Production and Allocation

    Directory of Open Access Journals (Sweden)

    Richard B. Hall

    2013-07-01

    Full Text Available Hybrid poplars have demonstrated high productivity as short rotation woody crops (SRWC in the Midwest USA, and the hybrid aspen “Crandon” (Populus alba L. × P. grandidenta Michx. has exhibited particularly promising yields on marginal lands. However, a key obstacle for wider deployment is the lack of economic returns early in the rotation. Alleycropping has the potential to address this issue, especially when paired with crops such as winter triticale which complete their growth cycle early in the summer and therefore are expected to exert minimal competition on establishing trees. In addition, well-placed fertilizer in low rates at planting has the potential to improve tree establishment and shorten the rotation, which is also economically desirable. To test the potential productivity of “Crandon” alleycropped with winter triticale, plots were established on five topographic positions with four different rates of fertilizer placed in the planting hole. Trees were then harvested from the plots after each of the first three growing seasons. Fertilization resulted in significant increases in branch, stem, and total aboveground biomass across all years, whereas the effects of topographic position varied by year. Allocation between branches and stems was found to be primarily a function of total aboveground biomass.

  19. Inventory of aspen trees in spruce dominated stands in conservation area

    Institute of Scientific and Technical Information of China (English)

    Matti Maltamo; Annukka Pesonen; Lauri Korhonen; Jari Kouki; Mikko Vehmas; Kalle Eerikinen

    2015-01-01

    Background:The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging. Methods:We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes:volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collected from three separate forest stands in Koli National Park, eastern Finland. At each site, we measured breast height diameter and coordinates of each aspen. The comparison of inventory methods of aspens within the three stands was based on simulations with mapped field data. We mimicked stand level inventory by locating varying numbers of fixed area circular plots both systematically and randomly within the stands. Additionally, we also tested if the use of airborne laser scanning (ALS) data as auxiliary information would improve the accuracy of the stand level inventory by applying the probability proportional to size sampling to assist the selection of field plot locations. Results:The results showed that aspens were always clustered, and the diameter distributions indicated different stand structures in the three investigated forest stands. The reliability of the volume and number of large aspen trees varied from relative root mean square error figures above 50%with fewer sample plots (5–10) to values of 25%–50%with 10 or more sample plots. Stand level inventory estimates were also able to detect spatial pattern and the shape of the diameter distribution. In addition, ALS-based auxiliary information could be useful in guiding the inventories, but caution should be used when applying the ALS-supported inventory technique. Conclusions:This study characterized European aspen populations for the purposes of monitoring and management of boreal conservation areas. Our results suggest that

  20. Inventory of aspen trees in spruce dominated stands in conservation area

    Directory of Open Access Journals (Sweden)

    Matti Maltamo

    2015-05-01

    Full Text Available Background The occurrence of aspen trees increases the conservation value of mature conifer dominated forests. Aspens typically occur as scattered individuals among major tree species, and therefore the inventory of aspens is challenging. Methods We characterized aspen populations in a boreal nature reserve using diameter distribution, spatial pattern, and forest attributes: volume, number of aspens, number of large aspen stems and basal area median diameter. The data were collected from three separate forest stands in Koli National Park, eastern Finland. At each site, we measured breast height diameter and coordinates of each aspen. The comparison of inventory methods of aspens within the three stands was based on simulations with mapped field data. We mimicked stand level inventory by locating varying numbers of fixed area circular plots both systematically and randomly within the stands. Additionally, we also tested if the use of airborne laser scanning (ALS data as auxiliary information would improve the accuracy of the stand level inventory by applying the probability proportional to size sampling to assist the selection of field plot locations. Results The results showed that aspens were always clustered, and the diameter distributions indicated different stand structures in the three investigated forest stands. The reliability of the volume and number of large aspen trees varied from relative root mean square error figures above 50% with fewer sample plots (5–10 to values of 25%–50% with 10 or more sample plots. Stand level inventory estimates were also able to detect spatial pattern and the shape of the diameter distribution. In addition, ALS-based auxiliary information could be useful in guiding the inventories, but caution should be used when applying the ALS-supported inventory technique. Conclusions This study characterized European aspen populations for the purposes of monitoring and management of boreal conservation areas. Our

  1. Photoperiodic growth control in perennial trees.

    Science.gov (United States)

    Azeez, Abdul; Sane, Aniruddha P

    2015-01-01

    Plants have to cope with changing seasons and adverse environmental conditions. Being sessile, plants have developed elaborate mechanisms for their survival that allow them to sense and adapt to the environment and reproduce successfully. A major adaptive trait for the survival of trees of temperate and boreal forests is the induction of growth cessation in anticipation of winters. In the last few years enormous progress has been made to elucidate the molecular mechanisms underlying SDs induced growth cessation in model perennial tree hybrid aspen (Populus tremula × P. tremuloides). In this review we discuss the molecular mechanism underlying photoperiodic control of growth cessation and adaptive responses.

  2. 基于Aspen Plus的克劳斯硫回收过程模拟%Analog of ClausSulfur Recovery Process Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    林发现; 丁玲; 陈延林; 李繁荣; 师慧灵; 邹隐文

    2011-01-01

    Adopting Aspen Plus process analog calculation software,process flow for Claus sulfur recovery was simulated,simulated data was good coincident with the data demarcated by analog software used specially for sulfur recovery;on that basis,author has studied the influence of Claus key data on process flow by use of Aspen Plus modular analysis function,its conclusion was coincident with practical production process;result indicates that it has optimizing role for both design calculation and production operation based on the Claus sulfur recovery process analog.%采用Aspen P lus工艺模拟计算软件模拟了克劳斯硫回收工艺过程,模拟数据与硫回收专用模拟软件的标定数据吻合较好;在此基础上,利用Aspen P lus模块化分析功能,研究了克劳斯工艺的关键数据对工艺过程的影响,其结论与实际生产过程相符合;结果表明,基于Aspen P lus的克劳斯硫回收过程模拟,对设计计算和生产操作均具有优化作用。

  3. Conservation status of white poplar (Populus alba L. and black poplar (Populus nigra L. in the territory of Great War Island

    Directory of Open Access Journals (Sweden)

    Šijačić-Nikolić Mirjana

    2014-01-01

    Full Text Available T he paper describes t he conservation status of white poplar (Populus alba L. and black poplar (Populus nigra L. in the territory of Great War Island. The activities of in situ and ex situ gene pool conservation have been defined in order to preserve and expand the populations of the above species, as carriers of complex wetland forest ecosystems.

  4. Simulation of IGFC power generation system by Aspen Plus

    DEFF Research Database (Denmark)

    Rudra, Souman; Rosendahl, Lasse; Sayem, Abu Sadahat

    2010-01-01

    The solid oxide fuel cell (SOFC) is a promising technology for electricity generation. Sulfur free syngas from the gas cleaning unit serves as a fuel for SOFC in IGFC (Integrated gasification Fuel cell) power plant. It converts the chemical energy of the fuel gas directly to electric energy...... efficiency and power with respect to a variety of SOFC inputs. HRSG which is located after the SOFC is also included in current simulation study with various operating parameters. This paper also describes for the IGFC Power Plants, the optimization of the Heat Recovery Steam Generator (HRSG...... and therefore, very high efficiencies can be achieved. The outputs from SOFC can be utilized by HRSG which drives steam turbine for electricity production. The SOFC stack model developed using the process flow sheet simulator Aspen Plus which is of equilibrium type. The results indicate there must be tread off...

  5. Orbital Express Mission Operations Planning and Resource Management using ASPEN

    Science.gov (United States)

    Chouinard, Caroline; Knight, Russell; Jones, Grailing; Tran, Danny

    2008-01-01

    The Orbital Express satellite servicing demonstrator program is a DARPA program aimed at developing "a safe and cost-effective approach to autonomously service satellites in orbit". The system consists of: a) the Autonomous Space Transport Robotic Operations (ASTRO) vehicle, under development by Boeing Integrated Defense Systems, and b) a prototype modular next-generation serviceable satellite, NEXTSat, being developed by Ball Aerospace. Flexibility of ASPEN: a) Accommodate changes to procedures; b) Accommodate changes to daily losses and gains; c) Responsive re-planning; and d) Critical to success of mission planning Auto-Generation of activity models: a) Created plans quickly; b) Repetition/Re-use of models each day; and c) Guarantees the AML syntax. One SRP per day vs. Tactical team

  6. 2013 Aspen Winter Conference on particle physics: Higgs Quo Vadis

    CERN Document Server

    2013-01-01

    By winter of 2013, the ATLAS and CMS experiments at the LHC will establish their discovery of a new Higgs-like particle with a mass around 125 GeV. The new data will shed light on its properties. Many fundamental questions in Physics will start to get their answer. The 2013 Aspen Winter Conference on particle physics will bring together experimentalists and theorists, creating an ideal environment to present and discuss the implications of the Higgs discovery in the framework of the Standrad Model and beyond. The conference will be formulated to encourage close collaborations and active exchange of information, which is crucial for making progress on this central topic of particle physics.

  7. Best Practices Case Study: Shaw Construction Burlingame Ranch Ph.1, Aspen, CO

    Energy Technology Data Exchange (ETDEWEB)

    Pacific Northwest National Laboratory & Oak Ridge National Laboratory

    2010-12-01

    Shaw Construction built 84 energy efficient, affordable condominiums forthe City of Aspen that achieved HERS scores of less than 62 with help from Building America’s research team lead Building Science Corporation.

  8. 78 FR 46312 - Spruce Beetle Epidemic and Aspen Decline Management Response; Grand Mesa, Uncompahgre and...

    Science.gov (United States)

    2013-07-31

    ...-of-way and border zones. Other priority treatment areas may be identified through the analysis and... conditions of spruce-fir and healthy clones of aspen. Removal of single trees or group selections of...

  9. The application of Aspen Plus server in software integration%Aspen Plus服务器在软件集成中的应用

    Institute of Scientific and Technical Information of China (English)

    孔祥冰; 岳金彩; 谭心舜; 焦巍

    2007-01-01

    ActiveX控件作为可重复使用的程序和数据可集成到其它应用程序中,Aspen Plus用户界面就是一个ActiveX服务器应用程序,利用接口程序能够将用户对装置模型及其参数的改变传递给Aspen Plus,再把模拟结果与外部应用程序相连接,实现软件集成.本文对Aspen Plus的服务器功能进行了探讨,并介绍了这个功能的详细开发步骤和编写方法,最后给出了一个吸收塔的具体接口实例.

  10. Enhancement of production of eugenol and its glycosides in transgenic aspen plants via genetic engineering.

    OpenAIRE

    Koeduka, Takao; Suzuki, Shiro; Iijima, Yoko; Ohnishi, Toshiyuki; Suzuki, Hideyuki; Watanabe, Bunta; Shibata, Daisuke; Umezawa, Toshiaki; Pichersky, Eran; Hiratake, Jun

    2013-01-01

    Eugenol, a volatile phenylpropene found in many plant species, exhibits antibacterial and acaricidal activities. This study attempted to modify the production of eugenol and its glycosides by introducing petunia coniferyl alcohol acetyltransferase (PhCFAT) and eugenol synthase (PhEGS) into hybrid aspen. Gas chromatography analyses revealed that wild-type hybrid aspen produced small amount of eugenol in leaves. The heterologous overexpression of PhCFAT alone resulted in up to 7-fold higher eug...

  11. Genetic variation of hydraulic and wood anatomical traits in hybrid poplar and trembling aspen.

    Science.gov (United States)

    Schreiber, Stefan G; Hacke, Uwe G; Hamann, Andreas; Thomas, Barb R

    2011-04-01

    Intensive forestry systems and breeding programs often include either native aspen or hybrid poplar clones, and performance and trait evaluations are mostly made within these two groups. Here, we assessed how traits with potential adaptive value varied within and across these two plant groups. Variation in nine hydraulic and wood anatomical traits as well as growth were measured in selected aspen and hybrid poplar genotypes grown at a boreal planting site in Alberta, Canada. Variability in these traits was statistically evaluated based on a blocked experimental design. We found that genotypes of trembling aspen were more resistant to cavitation, exhibited more negative water potentials, and were more water-use-efficient than hybrid poplars. Under the boreal field test conditions, which included major regional droughts, height growth was negatively correlated with branch vessel diameter (Dv ) in both aspen and hybrid poplars and differences in Dv were highly conserved in aspen trees from different provenances. Differences between the hybrid poplars and aspen provenances suggest that these two groups employ different water-use strategies. The data also suggest that vessel diameter may be a key trait in evaluating growth performance in a boreal environment.

  12. Aspen Plus在化工专业课程教学中的应用%Application of Aspen Plus in the teaching of chemical engineering major

    Institute of Scientific and Technical Information of China (English)

    郑建东; 徐杰; 冯建华; 杨靖

    2016-01-01

    为了培养学生的工程实践能力,将Aspen Plus软件应用于化学工程与工艺专业课程教学.介绍了Aspen Plus软件在课堂教学中的应用,从而提高学生对化工专业课程的理解能力,增强学生的工程意识,有助于学生学习兴趣的提高.

  13. The Application of Aspen Plus in Chemical Engineering Learning%Aspen Plus在化工学习中的应用

    Institute of Scientific and Technical Information of China (English)

    滑纬博; 李云凯; 吕燕

    2013-01-01

    在化工学习中,应用Aspen Plus对化工生产中的典型工艺——苯加氢合成环己烷系统进行模拟,结果表明,Aspen Plus不仅可以简化复杂的化工过程,而且可以提高学生学习的效率和质量,增强工程意识,有利于理论和实践的结合.

  14. Applications of Aspen Plus in the teaching of the separation engineering%Aspen Plus在《分离工程》教学中的应用

    Institute of Scientific and Technical Information of China (English)

    卢泽湘; 范立维; 廖益强

    2010-01-01

    分析了Aspen Plus化工流程模拟软件的学习方法,探讨了Aspen Plus软件在课程教学改革中的运用.教改结果表明,教学中软件的应用提高了学生的学习兴趣,加深了学生对课程内容的理解,同时拓宽了学生的视野,使课程教学更接近工程实际,获得了良好的教学效果.

  15. Aspen Plus Applied in Teaching of Chemical Engineering Design%Aspen plus在化工设计教学中应用

    Institute of Scientific and Technical Information of China (English)

    汪斌; 舒莉; 朱炳龙

    2010-01-01

    化工流程模拟软件Aspen plus在化工过程设计中得到了普遍应用,显著提高了化工工艺流程等方面的设计效率和水平.主要介绍该软件功能和应用方法,结合苯和甲苯精馏塔设计计算,讨论其在化工课程设计中的应用.将Aspen plus模拟值与文献值进行比较,相对误差小,符合较好.

  16. Effect of Different Photoperiods on Cold Hardiness in Cherry

    Directory of Open Access Journals (Sweden)

    A.Z. Makaraci

    2009-01-01

    Full Text Available In this research we have investigated the effects of different photoperiods on cold hardiness of cherry trees (Prunus avium cv. Ulster. One year old, cherry trees were exposed 8 hours of day length and 16 hours of dark period for short day conditions and 16 hours of light and 8 hours of dark period for long day conditions. We also compared the acclimatization pattern of cherry trees with hybrid aspen (Populus tremula ×Populus tremuloides trees. LT50 values indicated that short day and long day conditions did not alter the cold hardiness of cherry trees. Under the same experimental conditions hybrid aspen trees were affected from different photoperiods. Aspen trees exposed to short day conditions were hardier than the trees exposed to long day conditions. We also investigated the acclimatization the patterns of basal and apical parts of the branches both in cherry and aspen trees. There were no significant differences in cold hardiness of the basal and apical parts of the branches in aspen and cherry trees.

  17. Increasing the productivity of short-rotation Populus plantations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    DeBell, D.S.; Harrington, C.A.; Clendenen, G.W.; Radwan, M.A.; Zasada, J.C. [Forest Service, Olympia, WA (United States). Pacific Northwest Research Station

    1997-12-31

    This final report represents the culmination of eight years of biological research devoted to increasing the productivity of short rotation plantations of Populus trichocarpa and Populus hybrids in the Pacific Northwest. Studies provide an understanding of tree growth, stand development and biomass yield at various spacings, and how patterns differ by Populus clone in monoclonal and polyclonal plantings. Also included is some information about factors related to wind damage in Populus plantings, use of leaf size as a predictor of growth potential, and approaches for estimating tree and stand biomass and biomass growth. Seven research papers are included which provide detailed methods, results, and interpretations on these topics.

  18. Impact of Drying Methods on Wettability of Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Plantation poplar is one of the most important resources for wood industry, its utilization field is vast. The wettability of Populus tomentosa with different drying methods was judged by measurement of contact angle using distilled water in this paper. The results showed that the specimens from conventional drying have the biggest contact angle, and the air dried have the smallest contact angle, air dried lumbers have a better wettability than the kiln dried. The changes of contact angle in a period of tim...

  19. Stress-responsive hydroxycinnamate glycosyltransferase modulates phenylpropanoid metabolism in Populus

    OpenAIRE

    2014-01-01

    The diversity of phenylpropanoids offers a rich inventory of bioactive chemicals that can be exploited for plant improvement and human health. Recent evidence suggests that glycosylation may play a role in the partitioning of phenylpropanoid precursors for a variety of downstream uses. This work reports the functional characterization of a stress-responsive glycosyltransferase, GT1-316 in Populus. GT1-316 belongs to the UGT84A subfamily of plant glycosyltransferase family 1 and is designated ...

  20. Predation risk, elk, and aspen: tests of a behaviorally mediated trophic cascade in the Greater Yellowstone Ecosystem.

    Science.gov (United States)

    Winnie, John A

    2012-12-01

    Aspen in the Greater Yellowstone Ecosystem are hypothesized to be recovering from decades of heavy browsing by elk due to a behaviorally mediated trophic cascade (BMTC). Several authors have suggested that wolves interact with certain terrain features, creating places of high predation risk at fine spatial scales, and that elk avoid these places, which creates refugia for plants. This hypothesized BMTC could release aspen from elk browsing pressure, leading to a patchy recovery in places of high risk. I tested whether four specific, hypothesized fine-scale risk factors are correlated with changes in current elk browsing pressure on aspen, or with aspen recruitment since wolf reintroduction, in the Daly Creek drainage in Yellowstone National Park, and near two aspen enclosures outside of the park boundary. Aspen were not responding to hypothesized fine-scale risk factors in ways consistent with the current BMTC hypothesis.

  1. Using Populus as a lignocellulosic feedstock for bioethanol.

    Science.gov (United States)

    Porth, Ilga; El-Kassaby, Yousry A

    2015-04-01

    Populus species along with species from the sister genus Salix will provide valuable feedstock resources for advanced second-generation biofuels. Their inherent fast growth characteristics can particularly be exploited for short rotation management, a time and energy saving cultivation alternative for lignocellulosic feedstock supply. Salicaceae possess inherent cell wall characteristics with favorable cellulose to lignin ratios for utilization as bioethanol crop. We review economically important traits relevant for intensively managed biofuel crop plantations, genomic and phenotypic resources available for Populus, breeding strategies for forest trees dedicated to bioenergy provision, and bioprocesses and downstream applications related to opportunities using Salicaceae as a renewable resource. Challenges need to be resolved for every single step of the conversion process chain, i.e., starting from tree domestication for improved performance as a bioenergy crop, bioconversion process, policy development for land use changes associated with advanced biofuels, and harvest and supply logistics associated with industrial-scale biorefinery plants using Populus as feedstock. Significant hurdles towards cost and energy efficiency, environmental friendliness, and yield maximization with regards to biomass pretreatment, saccharification, and fermentation of celluloses and the sustainability of biorefineries as a whole still need to be overcome.

  2. Characterization of MORE AXILLARY GROWTH genes in Populus.

    Directory of Open Access Journals (Sweden)

    Olaf Czarnecki

    Full Text Available Strigolactones are a new class of plant hormones that play a key role in regulating shoot branching. Studies of branching mutants in Arabidopsis, pea, rice and petunia have identified several key genes involved in strigolactone biosynthesis or signaling pathway. In the model plant Arabidopsis, MORE AXILLARY GROWTH1 (MAX1, MAX2, MAX3 and MAX4 are four founding members of strigolactone pathway genes. However, little is known about the strigolactone pathway genes in the woody perennial plants.Here we report the identification of MAX homologues in the woody model plant Populus trichocarpa. We identified the sequence homologues for each MAX protein in P. trichocarpa. Gene expression analysis revealed that Populus MAX paralogous genes are differentially expressed across various tissues and organs. Furthermore, we showed that Populus MAX genes could complement or partially complement the shoot branching phenotypes of the corresponding Arabidopsis max mutants.This study provides genetic evidence that strigolactone pathway genes are likely conserved in the woody perennial plants and lays a foundation for further characterization of strigolactone pathway and its functions in the woody perennial plants.

  3. The Challenges of Change. A Report from the Aspen Institute Seminar on Hispanic Americans and the Business Community (Aspen, Colorado, July 27-30, 1997).

    Science.gov (United States)

    McGuire, Georgianna; Nicolau, Siobhan

    This report from the 1997 Aspen Institute seminar concerns how demographic changes in American will affect Hispanic Americans' role in the business community. Section 1, "Lashes: Back, Front, and Sideways" (Harold Hodgkinson), describes pervasive national pessimism over demographic change and documents universal backlash to that change among all…

  4. Residential Access to Bandwidth: Exploring New Paradigms. A Report of the Annual Aspen Institute Conference on Telecommunications Policy (13th, August 9-13, 1998, Aspen, Colorado).

    Science.gov (United States)

    Entman, Robert M.

    The 1998 Aspen Systems Conference on Telecommunications Policy met to consider ways of speeding the deployment of telecommunication systems that allow for robust, reliable, and innovative communications services to the home. By organizing participants into three working groups, the session was able to come up with analytical suggestions and policy…

  5. Impact of epidermal leaf mining by the aspen leaf miner (Phyllocnistis populiella) on the growth, physiology, and leaf longevity of quaking aspen.

    Science.gov (United States)

    Wagner, Diane; DeFoliart, Linda; Doak, Patricia; Schneiderheinze, Jenny

    2008-08-01

    The aspen leaf miner, Phyllocnistis populiella, feeds on the contents of epidermal cells on both top (adaxial) and bottom (abaxial) surfaces of quaking aspen leaves, leaving the photosynthetic tissue of the mesophyll intact. This type of feeding is taxonomically restricted to a small subset of leaf mining insects but can cause widespread plant damage during outbreaks. We studied the effect of epidermal mining on aspen growth and physiology during an outbreak of P. populiella in the boreal forest of interior Alaska. Experimental reduction of leaf miner density across two sites and 3 years significantly increased annual aspen growth rates relative to naturally mined controls. Leaf mining damage was negatively related to leaf longevity. Leaves with heavy mining damage abscised 4 weeks earlier, on average, than leaves with minimal mining damage. Mining damage to the top and bottom surfaces of leaves had different effects on physiology. Mining on the top surface of the leaf had no significant effect on photosynthesis or conductance and was unrelated to leaf stable C isotope ratio (delta(13)C). Mining damage to the bottom leaf surface, where stomata are located, had significant negative effects on net photosynthesis and water vapor conductance. Percent bottom mining was positively related to leaf delta(13)C. Taken together, the data suggest that the primary mechanism for the reduction of photosynthesis by epidermal leaf mining by P. populiella is the failure of stomata to open normally on bottom-mined leaves.

  6. Aspen Plus 在化工热力学教学中的应用%Applications of Aspen Plus in the Teaching of Chemical Engineering Thermodynamics

    Institute of Scientific and Technical Information of China (English)

    丁雪; 刘熠斌; 宋春敏; 乔柯

    2014-01-01

    化工热力学是一门理论性强、逻辑性强、概念抽象、公式繁多的专业基础课。本文介绍了在化工热力学教学过程中引入Aspen Plus软件进行辅助教学,在优化教学内容、改善教学方法、提高学习效率、强化课程基础等方面进行有益的探索,认为引入Aspen Plus软件可以提高学生的学习兴趣,加深学生对课程内容的理解,提高学生的工程实践能力。%Chemical Engineering Thermodynamics was a professional basic course with strong theory , logicality , abstract concept and lots of formula.The citation of Aspen Plus to the teaching of chemical engineering thermodynamics was introduced.How to improve teaching content , teaching method , study efficiency and course base were investigated.When used Aspen Plus in the teaching of chemical engineering hemodynamics , the study interest , comprehension and engineering practice ability of students could be enhanced.

  7. The Application of Aspen Plus 7.3 in Chemical Engineering Design%Aspen Plus 7.3在化工设计中的应用

    Institute of Scientific and Technical Information of China (English)

    薛科创

    2014-01-01

    Chemical engineering design is the calculation process of the related parameters by computer. Because of the large amount of calculation, it must through the corresponding chemical simulation software to achieve. Aspen Plus 7.3 because the precise calculating, fast running speed, become the preferred software in chemical engineering design. This paper show the steps and methods of chemical engineering design by computer thought the flash condition is determined by Aspen Plus 7.3.%由于化工设计计算量大,必须通过相应的化工模拟软件来实现。Aspen Plus 7.3计算精确,运行速度快,成为化工设计者的首选软件。通过介绍利用Aspen Plus 7.3进行闪蒸条件的确定,说明利用计算机进行化工设计的步骤和方法。

  8. 基于Aspen Plus的褐煤热解过程模拟%The Lignite Coal Pyrolysis Process Simulation Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    王伟; 商玉坤; 武建军

    2011-01-01

    With high moisture lignite coal as an example, the method and procedure to build simplified model for coal pyrogenation process (CPD) using the chemical process simulation software Aspen Plus were introduced. Setting process of CPD model simulation parameter was given, and the Aspen Plus software was used to simulate the calculation process of coal pyrogenation, and the obtained simulation value was compared with the actual value. At the same time, the coal pyrolysis simulation process and the results were analyzed and provided basic reference to coal pyrogenation process development and optimization.%以高水分褐煤为例,介绍了利用Aspen Plus化工流程模拟软件建立煤热解过程简化模型的方法及步骤.阐述了CPD模型模拟参数的设置过程,并利用Aspen Plus软件对煤热解过程进行了模拟计算,将得出的模拟值与实际值进行了比较.同时,对煤热解模拟过程及结果进行了分析,给煤热解过程的工艺开发和工艺优化提供了参考依据.

  9. Dynamic Simulation of the Methanol Synthesis Reactor with the Aspen Dynamics Software%基于 Aspen Dynamics 的甲醇合成塔动态模拟

    Institute of Scientific and Technical Information of China (English)

    岳芳华; 刘东斌; 申延明

    2014-01-01

    以某年产300 kt甲醇合成装置为研究对象,利用先进的Aspen Plus工程设计软件对其进行全流程稳态模拟;并在稳态模拟的基础上,应用Aspen Dynamics软件对甲醇合成塔进行动态模拟,从而得到可供参考的最优的工艺控制参数,以指导实际生产操作。%Taking the 300 kt/a methanol synthesis unit as the study object ,make its whole process steady‐state simulation with the advanced Aspen Plus engineering design software . On the basis of steady‐state simulation ,make the dynamic simulation of methanol synthesis reactor with the Aspen Dynamics software to obtain the optimal control parameters for reference ,which could guide the actual production operations .

  10. Aspen Simulation of Diesel-Biodiesel Blends Combustion

    Directory of Open Access Journals (Sweden)

    Pérez-Sánchez Armando

    2015-01-01

    Full Text Available Biodiesel is a fuel produced by transesterification of vegetable oils or animal fats, which currently is gaining attention as a diesel substitute. It represents an opportunity to reduce CO2, SO2, CO, HC, PAH and PM emissions and contributes to the diversification of fuels in Mexico's energetic matrix. The results of the simulation of the combustion process are presented in this paper with reference to an engine specification KUBOTA D600-B, operated with diesel-biodiesel blends. The physicochemical properties of the compounds and the operating conditions of equipment were developed using the simulator Aspen® and supplementary information. The main aspects of the engine working conditions were considered such as diesel-biodiesel ratio, air/fuel mixture, temperature of the combustion gases and heat load. Diesel physicochemical specifications were taken from reports of PEMEX and SENER. Methyl esters corresponding to the transesterification of fatty acids that comprise castor oil were regarded as representative molecules of biodiesel obtained from chromatographic analysis. The results include CO2, water vapor, combustion efficiency, power and lower calorific value of fuels.

  11. Analysis of the Correlation between the Geographical Distribution of Populus euphratica Oliv. and the Climatic Environment

    Institute of Scientific and Technical Information of China (English)

    Yinke YANG; Zhenglong YAN

    2012-01-01

    [Objective] This research was to study the correlation regional climatic characteristics and changing geographic distribution of Populus euphratica Oily. (Sali- caceae), as well as the adaption of Populus euphratica Oliv. to the climatic environ- ment. [Method] The climatic characteristics, water source, groundwater and soil type in the distribution regions of Populus euphratica Oliv. and the effect of long-term hu- man activities were comprehensively analyzed based an overview of Populus eu- phratica Oliv. and its distribution. [Result] Specific regional climatic characteristics and long term human activities are the principle determinants for the growth of Populus euphratica Oliv. The change of leaf shape is a distinct feature of Populus euphratica Oliv. in adapting to the climatic environment. Populus euphratica Oliv. withstands various environmental stresses by means of in vivo synthesis, transport and conver- sion of secondary phenolic metabolites. Effective protection and rehabilitation mea- sures, and ecological water transport have obvious effect on the restoration and re- construction of damaged ecological environment of Populus euphratica oasis. [Con- clusion] This study is of great significance for the restoration of ecological environ- ment in the arid inland regions, north-west China.

  12. Differential response of aspen and birch trees to heat stress under elevated carbon dioxide.

    Science.gov (United States)

    Darbah, Joseph N T; Sharkey, Thomas D; Calfapietra, Carlo; Karnosky, David F

    2010-04-01

    The effect of high temperature on photosynthesis of isoprene-emitting (aspen) and non-isoprene-emitting (birch) trees were measured under elevated CO(2) and ambient conditions. Aspen trees tolerated heat better than birch trees and elevated CO(2) protected photosynthesis of both species against moderate heat stress. Elevated CO(2) increased carboxylation capacity, photosynthetic electron transport capacity, and triose phosphate use in both birch and aspen trees. High temperature (36-39 degrees C) decreased all of these parameters in birch regardless of CO(2) treatment, but only photosynthetic electron transport and triose phosphate use at ambient CO(2) were reduced in aspen. Among the two aspen clones tested, 271 showed higher thermotolerance than 42E possibly because of the higher isoprene-emission, especially under elevated CO(2). Our results indicate that isoprene-emitting trees may have a competitive advantage over non-isoprene emitting ones as temperatures rise, indicating that biological diversity may be affected in some ecosystems because of heat tolerance mechanisms.

  13. Synergetic hydrothermal co-liquefaction of crude glycerol and aspen wood

    DEFF Research Database (Denmark)

    Pedersen, Thomas Helmer; Jasiunas, Lukas; Casamassima, Luca

    2015-01-01

    Crude glycerol-assisted hydrothermal co-liquefaction of aspen wood was studied in batch micro-reactors. An experimental matrix of 14 experiments was defined to investigate the effects of three different process parameters on the yields of biocrude and char, and on biocrude quality. Co-processing ......Crude glycerol-assisted hydrothermal co-liquefaction of aspen wood was studied in batch micro-reactors. An experimental matrix of 14 experiments was defined to investigate the effects of three different process parameters on the yields of biocrude and char, and on biocrude quality. Co......-processing aspen wood and neat glycerol led to a significant reduction in the char yield, and glycerol is hypothesized to act as a radical scavenger, alleviating re-polymerization of especially lignin-derived fragments. In the temperature range of 380–420 °C, it was found that biocrude and char yield, and biocrude...... quality were all invariant to the reaction temperature. By increasing the crude glycerol to aspen wood mass ratio from 0:1 to 3:1, char yield was decreased from 18.3% (only aspen wood) to 3.4%. Furthermore, the biocrude quality in terms of the effective hydrogen-to-carbon ratio (H/Ceff) was significantly...

  14. The Internet Time Lag: Anticipating the Long-Term Consequences of the Information Revolution. A Report of the Annual Aspen Institute Roundtable on Information Technology (10th, Aspen, Colorado, August 2-5, 2001).

    Science.gov (United States)

    Schwartz, Evan I.

    This is a report of the 10th annual Aspen Institute Roundtable on Information Technology (Aspen, Colorado, August 2-5, 2001). Participants were also polled after the events of September 11, and these comments have been integrated into the report. The mission of this report is to take a wide-ranging look at the trends that are defining the next new…

  15. 76 FR 15306 - Aspen Merchant Energy LP; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2011-03-21

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Aspen Merchant Energy LP; Supplemental Notice That Initial Market-Based Rate...-referenced proceeding of Aspen Merchant Energy LP's application for market-based rate authority, with...

  16. Glycosylation-mediated phenylpropanoid partitioning in Populus tremuloides cell cultures

    Directory of Open Access Journals (Sweden)

    Babst Benjamin A

    2009-12-01

    Full Text Available Abstract Background Phenylpropanoid-derived phenolic glycosides (PGs and condensed tannins (CTs comprise large, multi-purpose non-structural carbon sinks in Populus. A negative correlation between PG and CT concentrations has been observed in several studies. However, the molecular mechanism underlying the relationship is not known. Results Populus cell cultures produce CTs but not PGs under normal conditions. Feeding salicyl alcohol resulted in accumulation of salicins, the simplest PG, in the cells, but not higher-order PGs. Salicin accrual reflected the stimulation of a glycosylation response which altered a number of metabolic activities. We utilized this suspension cell feeding system as a model for analyzing the possible role of glycosylation in regulating the metabolic competition between PG formation, CT synthesis and growth. Cells accumulated salicins in a dose-dependent manner following salicyl alcohol feeding. Higher feeding levels led to a decrease in cellular CT concentrations (at 5 or 10 mM, and a negative effect on cell growth (at 10 mM. The competition between salicin and CT formation was reciprocal, and depended on the metabolic status of the cells. We analyzed gene expression changes between controls and cells fed with 5 mM salicyl alcohol for 48 hr, a time point when salicin accumulation was near maximum and CT synthesis was reduced, with no effect on growth. Several stress-responsive genes were up-regulated, suggestive of a general stress response in the fed cells. Salicyl alcohol feeding also induced expression of genes associated with sucrose catabolism, glycolysis and the Krebs cycle. Transcript levels of phenylalanine ammonia lyase and most of the flavonoid pathway genes were reduced, consistent with down-regulated CT synthesis. Conclusions Exogenous salicyl alcohol was readily glycosylated in Populus cell cultures, a process that altered sugar utilization and phenolic partitioning in the cells. Using this system, we

  17. Stand Dynamics, Humus Type and Water Balance Explain Aspen Long Term Productivity across Canada

    Directory of Open Access Journals (Sweden)

    Kenneth A. Anyomi

    2015-02-01

    Full Text Available This study examined the relative importance of soil, stand development and climate hypotheses in driving productivity for a species that is widely distributed in North America. Inventory plots, 3548 of such, either dominated by aspen or made up of species mixture of which aspen occurs in dominant canopy position were sampled along a longitudinal gradient from Quebec to British Columbia. Site index (SI, was used as a measure of productivity, and soil, climate and stand attributes were correlated with site index in order to determine their effects on productivity. Results show a decline in productivity with high moisture deficit. Soil humus correlates significantly with SI but does not sufficiently capture differential rates of litter deposition and decomposition effects over the long-term. Consequently, aspen composition, stand ageing, and stand structural changes dominate variability in productivity. Within the context where deciduous cover has being increasing, there are implications for forest productivity.

  18. Fibrillation of Aspen by Alkaline Cold Pre-treatment and Vibration Milling

    Directory of Open Access Journals (Sweden)

    Kärt KÄRNER

    2016-09-01

    Full Text Available In this article an attempt to fibrillate aspen bleached chemi-thermo mechanical pulp (BCTMP fibre in an environmentally friendly way is reported. The effects of various NaOH, KOH, urea and ethanol aqueous solutions at lowered temperature were tested for pre-treatment. The pre-treatment was followed by vibration milling aiming to peel off outer cell wall layers and to fibrillate S2 layer of the aspen wood fibre. The effects of the treatments were evaluated by scanning electron microscopy (SEM. The results show that it is possible to fibrillate BCTMP aspen fibres by using alkaline aqueous solutions at low temperatures followed by a mechanical treatment. A strong dependence on fibrillation of cellulose on temperature, time and alkali concentration was established.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7412

  19. Improvement of bleached wheat straw pulp properties by using aspen high-yield pulp.

    Science.gov (United States)

    Zhang, Hongjie; Li, Jianguo; Hu, Huiren; He, Zhibin; Ni, Yonghao

    2012-09-01

    The bleached wheat straw pulp (BWSP) accounts for about 25% of the virgin fiber supply in the Chinese Pulp and Paper Industry. As a non-wood chemical pulp, BWSP is known to have low bulk, low light scattering coefficient and poor drainage due to its high content of parenchyma cells. In this study, a high-quality aspen high-yield pulp (HYP) was used to improve the BWSP properties at the laboratory scale. The results indicate that adding 5-20% aspen HYP into unrefined or refined BWSP can minimize many of the drawbacks associated with the BWSP: improving its drainage, bulk, light scattering coefficient and opacity. The addition of a small amount (up to 20%) of aspen HYP can also significantly increase the tear index of BWSP with only a slight decrease of the tensile index.

  20. ASPEN PLUS在化工教学及科研中的应用

    Institute of Scientific and Technical Information of China (English)

    张毅博; 刘杨

    2015-01-01

    近年来,随着计算机技术的发展,大型的模拟仿真软件,尤其是Aspen Plus软件的应用,对推动化工专业教学及科研的发展起到了很大的作用。本文重点论述Aspen Plus软件在化工专业教学以及在科研中的应用。实践表明,Aspen Plus软件的使用,可以提高化工专业教学的质量,促进科研的的创新及发展。

  1. Aspen Plus”软件在化工生产中的应用

    Institute of Scientific and Technical Information of China (English)

    徐增花

    2013-01-01

      文章介绍了化工流程模拟软件“Aspen Plus”的主要功能及成功应用实例,应用实例表明,在化工生产中应用“Aspen Plus”软件不仅可以优化生产,而且还可以对某设备和整套生产装置的操作参数进行模拟分析,提高生产装置技术管理水平,从而产生巨大的经济效益,故应尽快在化工厂广大工程技术人员中推广使用“Aspen Plus”软件。

  2. Aspen Plus在化工专业教学中的应用

    Institute of Scientific and Technical Information of China (English)

    韩慧艳

    2013-01-01

    信息技术的普及推动了其在教育领域的应用,对提高教学质量起到了积极的促进作用。特别是Aspen Plus作为一种先进的计算机软件,凭借着较高的实验仿真能力,在化工专业教学中得到了广泛的应用。本文笔者在分析了化工专业课程体系的基础上,分析了Aspen Plus软件的优势,重点探讨了Aspen Plus在化工专业教学中的应用,目的是为化工专业教学提供指导和借鉴。

  3. Aspen Plus在泵选型设计中的应用

    Institute of Scientific and Technical Information of China (English)

    黄卫国

    2007-01-01

    应用Aspen Plus软件进行泵选型,先计算管线压降,初步确定泵的扬程和型号;然后输入泵的性能曲线,整个输送系统联合模拟,核算泵的性能。由于Aspen Plus软件拥有强大的物性数据库,所以输入简便,计算结果准确,可显著提高设计效率。

  4. Analysis of aspen-and-birch separated small woods’ vegetation in North Steppe of Ukraine

    Directory of Open Access Journals (Sweden)

    N. M. Nazarenko

    2010-09-01

    Full Text Available Conducted analysis of forest vegetation has allowed selecting and specifying classification and typological units of the aspen-and-birch separated small woods, which have statistically significant difference of ecotopic and coenotic parameters. Those parameters of studied forest ecosystems are characterised. Existence of the lines of hygrogenic and edaphogenic substitution, and succession rows are described. Phytoindication description of ecological factors’ pivotal conditions is presented. Driving factors determining parameters, structure and composition of the aspen-and-birch forest ecosystems are diminishing soil moisture, increasing annual temperatures amplitude and soil acidity.

  5. Initial characterization of shade avoidance response suggests functional diversity between Populus phytochrome B genes.

    Energy Technology Data Exchange (ETDEWEB)

    Karve, Abhijit A [ORNL; Weston, David [ORNL; Jawdy, Sara [ORNL; Gunter, Lee E [ORNL; Allen, Sara M [ORNL; Yang, Xiaohan [ORNL; Wullschleger, Stan D [ORNL; Tuskan, Gerald A [ORNL

    2012-01-01

    Shade avoidance signaling in higher plants involves perception of the incident red/far-red (R/FR) light by phytochromes and the modulation of downstream transcriptional networks to regulate developmental plasticity in relation to heterogeneous light environments. In this study, we characterized the expression and functional features of Populus phytochrome (PHY) gene family as well as the transcriptional responses of Populus to the changes in R/FR light. Expression data indicated that PHYA is the predominant PHY in the dark grown Populus seedling whereas PHYBs are most abundant in mature tissue types. Out of three Populus PHYs, PHYA is light labile and localized to cytosol in dark whereas both PHYB1 and PHYB2 are light stable and are localized to nucleus in mesophyll protoplasts. When expressed in Arabidopsis, PHYB1 rescued Arabidopsis phyB mutant phenotype whereas PHYB2 did not, suggesting functional diversification between these two gene family members. However, phenotypes of transgenic Populus lines with altered expression of PHYB1, PHYB2 or both and the expression of candidate shade response genes in these transgenic lines suggest that PHYB1 and PHYB2 may have distinct yet overlapping functions. The RNAseq results and analysis of Populus exposed to enriched-FR light indicate that genes associated in cell wall modification and brassinosteroid signaling were induced under far red light. Overall our data indicate that Populus transcriptional responses are at least partially conserved with Arabidopsis.

  6. OPTIMIZATION OF METHANOL/WATER SPLITTER WITH ASPEN PLUS%用AspenPlus优化甲醇水分离塔操作

    Institute of Scientific and Technical Information of China (English)

    姬加良

    2011-01-01

    To simulate the methanol/water splitter in Rectisol Plant with Aspen Plus engineering soft-ware for comparison with PDP;to optimize the working condition for the top methanol reflux under different water content and to compare the optimized data with the%应用AspenPlus工程软件对低温甲醇洗装置的甲醇水分离塔进行模拟,并与设计工艺包进行对比。对塔顶回流甲醇在不同含水量下的工况进行优化,将优化数据与该塔实际运行结果进行比较,为生产操作提供数据指导。

  7. Aspen Plus软件在气体分馏装置中的应用%Application of Aspen Plus in Gas Fractionation Plant

    Institute of Scientific and Technical Information of China (English)

    孙献菊

    2006-01-01

    介绍了Aspen Plus软件在齐鲁分公司胜利炼油厂气分装置上的应用情况,主要包括:利用Aspen Plus软件准确模拟了气分装置的生产工况,优化了脱丙烷塔的操作条件,并在实际中得到了应用.分析了原料变化后装置操作工艺条件的变化情况,为生产工艺方案的制定提供了很好的指导,缩短了装置的调整时间.

  8. Study of Coal Gasification System Based on ASPEN PLUS Platform%基于ASPEN PLUS平台煤气化系统研究

    Institute of Scientific and Technical Information of China (English)

    范峻铭; 诸林

    2014-01-01

    传统燃煤利用方式不仅造成煤热能利用效率低下,也使环境受到极大的破坏.煤气化是实现煤清洁和合理化利用的关键技术.目前多利用ASPEN PLUS软件模拟煤气化过程,并在该领域得到了越来越多的应用.因此,重点分析利用ASPEN PLUS建立煤气化模型的方法和原理,以期为今后研究提供方法性指导.

  9. Aspen Flare-net在火炬管网设计中的应用%Application of Aspen Flare-net in Design of Flare-net

    Institute of Scientific and Technical Information of China (English)

    匡顺强; 张斌

    2015-01-01

    介绍了Aspen Flare-net软件在火炬管网设计分析中的计算原理和计算步骤,并简要介绍了软件的主要特性、主要功能以及软件的计算选项。通过对一改扩建项目中新增的低压火炬排放气排放至原低压火炬系统进行火炬管网压力降核算分析,核算结果表明,原低压火炬系统无需改造,即可满足改扩建后新增低压火炬排放气的安全排放要求。同时表明Aspen Flare-net软件在火炬管网工程设计中的应用价值。%In this article, the calculating principles and procedures of software Aspen Flare-net were, including its maln characteristics, maln functions and application choices, introduced in the design and analysis of flare-net. With the analysis of pressure drop in lfare-net due to the discharge of gas from newly added low pressure lfare to the original low pressure lfare-net in one expanded project, it was concluded that it is unnecessary to reform the originated lfare-net that the safe discharge requirements for newly added low pressure lfare can be met. At the same times, it was shown that software Aspen Flare-net is quite useful in the design of lfare-net.

  10. Development & Application of Aspen Orion System in Refinery%炼油企业Aspen Orion系统开发与应用

    Institute of Scientific and Technical Information of China (English)

    王军

    2004-01-01

    随着全球经济的一体化,企业之间的竞争加剧.为降低成本、提高资源利用率,炼油企业都在积极运用优化技术和计算机技术追求利益的最大化.简要介绍了Aspen Orion系统及其在炼油厂的实际应用.

  11. Simulation of Rectified Reaction Process-Example of Using ASPEN PLUS%反应精馏过程模拟——ASPEN PLUS应用范例

    Institute of Scientific and Technical Information of China (English)

    杨绪壮; 屈一新

    2001-01-01

    本文利用ASPEN PLUS软件对环氧丙烷水解生成丙二醇的反应精馏过程进行模拟计算,对有关物系的相行为进行预测,并进行物性计算和流程模拟,指明了该反应过程的主反应区及其形成原因.

  12. 物性估算在ASPEN PLUS软件中的应用%Application of Properties Estimation in ASPEN PLUS Software

    Institute of Scientific and Technical Information of China (English)

    戚一文; 方云进

    2007-01-01

    利用Aspen Plus软件提供的物性估算功能,计算发酵液中低浓度1,3-丙二醇分离的中间产物2-甲基-1,3-二哑烷(2MD)的物性,从而模拟分离过程,确定工艺条件,得到理想的产物结果.

  13. Application of ASPEN PLUS in Methanol Distillation Column in MDI Plant%ASPEN PLUS在MDI装置的甲醇除去塔中的应用

    Institute of Scientific and Technical Information of China (English)

    徐宝学

    2008-01-01

    基于作者多年的工程技术开发经验介绍了ASPEN PLUS软件在MDI(二苯基甲烷二异氰酸酯)装置的甲醇除去塔设计中的应用,模拟与设计结果成功用于公司的16万t/a MDI的建设.

  14. Aspen Plus模拟汽油分馏塔系统%Simulation of gasoline fractionator system by Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    堵祖荫

    2002-01-01

    Aspen Plus模拟乙烯装置汽油分馏塔系统,其轻烃部分物性可以用Peng-Robison、Redich-Kwong-Seave等状态方程来描述,馏分油部分物性则用虚拟组分(Fictitious Components)描述,文章还以此研究了各工艺参数对塔板温度的影响.

  15. Aspen Plus在煤焦油复杂组分精馏中的应用%Application of Aspen Plus in the Complex Components Distillation

    Institute of Scientific and Technical Information of China (English)

    杨云; 许祥军

    2009-01-01

    在制备净化煤焦油沥青的过程中,净化沥青和轻质油组分的精馏分离是关键步骤之一.通过对组分的合理简化,用Aspen Plus对这一复杂组分精馏过程进行模拟,为试验及设计提供参考.

  16. ASPEN PLUS 对混合二甲苯分离工艺的分析研究%Research on Separation of mixed Xylene Using ASPEN PLUS

    Institute of Scientific and Technical Information of China (English)

    刘春法; 孙剑; 阮栋

    2005-01-01

    C8芳烃(混合二甲苯)由于组分来源的不同,组分较多,组分间沸点差很小,使C8芳烃分离可供选择的流程很多.化工分公司应用ASPEN PLUS软件,研究了超精馏工艺分离混合二甲苯的可行性.

  17. 乳化炸药水相的ASPEN PLUS物性分析%Emulsion Explosives' Water-phase Material ASPEN PLUS Analysis

    Institute of Scientific and Technical Information of China (English)

    曾开亮

    2013-01-01

    文章结合乳化炸药传统水相材料物性实际数据,用ASPEN PLUS软件对使用硝铵水溶液的水相材料在不同温度下进行了pure和binary物性分析,物性分析方法为PENG-ROB法和RK-SOAVE法,分析结果与实际数据相符合.

  18. APPLICATION OF ASPEN PLUS PROCESS SIMULATION SOFTWARE IN LLDPE PLANT%Aspen Plus流程模拟软件在LLDPE装置上的应用

    Institute of Scientific and Technical Information of China (English)

    高彤; 赵熠

    2008-01-01

    以LLDPE装置全流程模拟为例,对应用Aspen Plus软件进行分析和讨论.通过相关理论计算开发出了LLDPE装置流程模拟模型,并成功运用于实际生产,为安全稳定的进行牌号切换和开发新产品提供了依据.

  19. Stomatal uptake of O3 in aspen and aspen-birch forests under free-air CO2 and O3 enrichment.

    Science.gov (United States)

    Uddling, Johan; Hogg, Alan J; Teclaw, Ronald M; Carroll, Mary Anne; Ellsworth, David S

    2010-06-01

    Rising atmospheric carbon dioxide (CO2) may alleviate the toxicological impacts of concurrently rising tropospheric ozone (O3) during the present century if higher CO2 is accompanied by lower stomatal conductance (gs), as assumed by many models. We investigated how elevated concentrations of CO2 and O3, alone and in combination, affected the accumulated stomatal flux of O3 (AFst) by canopies and sun leaves in closed aspen and aspen-birch forests in the free-air CO2-O3 enrichment experiment near Rhinelander, Wisconsin. Stomatal conductance for O3 was derived from sap flux data and AFst was estimated either neglecting or accounting for the potential influence of non-stomatal leaf surface O3 deposition. Leaf-level AFst (AFst(l)) was not reduced by elevated CO2. Instead, there was a significant CO2 x O(3) interaction on AFst(l), as a consequence of lower values of gs in control plots and the combination treatment than in the two single-gas treatments. In addition, aspen leaves had higher AFst(l) than birch leaves, and estimates of AFst(l) were not very sensitive to non-stomatal leaf surface O3 deposition. Our results suggest that model projections of large CO2-induced reductions in gs alleviating the adverse effect of rising tropospheric O3 may not be reasonable for northern hardwood forests.

  20. The Application of Aspen One v7 in Chemical Separation Engineering Teaching%Aspen one v7在分离工程教学中的应用

    Institute of Scientific and Technical Information of China (English)

    路华清

    2010-01-01

    分离工程是化工类专业重要专业课,是一门实践性非常强的课程.各种平衡分离过程的计算既是教学的重点,又是教学的难点.随着电脑在学生中普及率的提高,为使用模拟软件进行辅助教学提供了条件.使用aspen one v7的aspen properties模块和aspen plu.模块辅助教学,学生在aspen properties中完成物性参数计算、逸度系数、活度系数、平衡常数计算、泡露点计算等分离工程基础数据计算,同时熟悉aspen one软件的使用,为后续在aspen plus中完成单级平衡分离计算、精馏吸收严格计算打下基础.同时,在分离工程教学过程中引入aspen one的应用,为后续课程"化工过程模拟"的教学打下基础,收到较好的教学效果.

  1. ADVANCING PROTOCOLS FOR POPLARS in vitro PROPAGATION, REGENERATION AND SELECTION OF TRANSFORMANTS

    Directory of Open Access Journals (Sweden)

    Nataliia Kutsokon

    2013-02-01

    Full Text Available Poplars (genus Populus have emerged as a model organism for forest biotechnology, and genetic modification is more advanced for this genus than for any other tree. So far several protocols for microclonal propagation and regeneration for Populus species have been developed. However it is well known that these protocols differ for various species and need to be adapted even for different clones of the same species. This work was focused on developing of protocols for propagation, regeneration and putative transformant´s selection of aspen Populus tremula L. and other two fast-growing Populus species (P. nigra L., P. x canadensis Moench. The regeneration ability for black poplar explants was demonstrated to be three times higher compared to those for aspen and hybrid poplar. It was found that concentration 1 mg/L of phosphinothricin and 25 mg/L of kanamycin is toxic for non- transgenic plant tissues of P. x canadensis and can be applied in transformation experiments when genes of resistance to the corresponding selective agents into the plant genome are introduced.

  2. Biomass production of hybrid aspen growing on former farm land in Sweden

    Institute of Scientific and Technical Information of China (English)

    Tord Johansson

    2013-01-01

    We construct dry weight equations for hybrid aspen growing on former farmland in Sweden.Dry weight equations for fractions of hybrid aspen trees were also made.We estimated biomass production in 24 stands.The stands were located in Sweden at latitudes ranging from 55 to 60° N.The mean age was 18 years (range 15-23),the mean stand density 1090 stems·ha-1 (range 378-2374),and the mean diameter at breast height (over bark) 178 mm (range 85-244 mm).Soil types in the hybrid aspen stands were mainly clay (21 stands),tills (2 stands) and other (1 stand).The mean total standing dry weight above stump level (≈200 mm) for the hybrid aspen stands was 135±53 t·ha-1 with a range of 42-219 t·ha-1.In addition to estimating conventional dry weights of trees and tree components,basic density,specific leaf area (SLA),projected leaf area (PLA) and leaf area index (LAI) were estimated and were in agreement with published figures.

  3. 75 FR 13805 - Aspen Group Resources Corp., Commercial Concepts, Inc., Desert Health Products, Inc., Equalnet...

    Science.gov (United States)

    2010-03-23

    ... COMMISSION Aspen Group Resources Corp., Commercial Concepts, Inc., Desert Health Products, Inc., Equalnet Communications Corp., Geneva Steel Holdings Corp., Orderpro Logistics, Inc. (n/k/a Securus Renewable Energy, Inc... accurate information concerning the securities of Commercial Concepts, Inc. because it has not filed...

  4. Risk Communication, Metacommunication, and Rhetorical Stases in the Aspen-EPA Superfund Controversy.

    Science.gov (United States)

    Stratman, James F.; And Others

    1995-01-01

    Explores the relationship between current theoretical definitions of risk communication, the unique national role that EPA plays in defining health and environmental risks, and possible explanations for EPA's inability to persuade Aspen, Colorado, to accept a cleanup plan. Explores ownership messages conveyed through metacommunication conflict…

  5. AspenTech to Provide VPS for CNOOC-Shell Nanhai Petrochemicals Complex

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ AspenTech, a US supplier of software and services to the process industries, recently announced it has been awarded a contract to supply a series of operator training simulators for the US$4.3 billion Nanhai Petrochemicals Project of CNOOC-Shell Petrochemical Company (CSPC)at Daya Bay in Huizhou City in South China's Guangdong Province.

  6. ASPEN, the Alberta Special Education Network: Using Appropriate Technology to Bring the Community Together.

    Science.gov (United States)

    Hill, W. Leigh; Anthony, Matthew

    1991-01-01

    The Alberta Special Education Network (ASPEN) is a computer-based communications and information network geared to the teaching and learning of exceptional children in rural Alberta, Canada. Network features include toll-free telephone access, a menu-driven user interface, training and awareness, electronic mail, weekly news, forums, and a…

  7. ASPEN Plus in the Chemical Engineering Curriculum: Suitable Course Content and Teaching Methodology

    Science.gov (United States)

    Rockstraw, David A.

    2005-01-01

    An established methodology involving the sequential presentation of five skills on ASPEN Plus to undergraduate seniors majoring in ChE is presented in this document: (1) specifying unit operations; (2) manipulating physical properties; (3) accessing variables; (4) specifying nonstandard components; and (5) applying advanced features. This…

  8. ASPEN+ and economic modeling of equine waste utilization for localized hot water heating via fast pyrolysis

    Science.gov (United States)

    ASPEN Plus based simulation models have been developed to design a pyrolysis process for the on-site production and utilization of pyrolysis oil from equine waste at the Equine Rehabilitation Center at Morrisville State College (MSC). The results indicate that utilization of all available Equine Reh...

  9. Enhancement of production of eugenol and its glycosides in transgenic aspen plants via genetic engineering.

    Science.gov (United States)

    Koeduka, Takao; Suzuki, Shiro; Iijima, Yoko; Ohnishi, Toshiyuki; Suzuki, Hideyuki; Watanabe, Bunta; Shibata, Daisuke; Umezawa, Toshiaki; Pichersky, Eran; Hiratake, Jun

    2013-06-21

    Eugenol, a volatile phenylpropene found in many plant species, exhibits antibacterial and acaricidal activities. This study attempted to modify the production of eugenol and its glycosides by introducing petunia coniferyl alcohol acetyltransferase (PhCFAT) and eugenol synthase (PhEGS) into hybrid aspen. Gas chromatography analyses revealed that wild-type hybrid aspen produced small amount of eugenol in leaves. The heterologous overexpression of PhCFAT alone resulted in up to 7-fold higher eugenol levels and up to 22-fold eugenol glycoside levels in leaves of transgenic aspen plants. The overexpression of PhEGS alone resulted in a subtle increase in either eugenol or eugenol glycosides, and the overexpression of both PhCFAT and PhEGS resulted in significant increases in the levels of both eugenol and eugenol glycosides which were nonetheless lower than the increases seen with overexpression of PhCFAT alone. On the other hand, overexpression of PhCFAT in transgenic Arabidopsis and tobacco did not cause any synthesis of eugenol. These results indicate that aspen leaves, but not Arabidopsis and tobacco leaves, have a partially active pathway to eugenol that is limited by the level of CFAT activity and thus the flux of this pathway can be increased by the introduction of a single heterologous gene.

  10. Final Harvest of Above-Ground Biomass and Allometric Analysis of the Aspen FACE Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mark E. Kubiske

    2013-04-15

    The Aspen FACE experiment, located at the US Forest Service Harshaw Research Facility in Oneida County, Wisconsin, exposes the intact canopies of model trembling aspen forests to increased concentrations of atmospheric CO2 and O3. The first full year of treatments was 1998 and final year of elevated CO2 and O3 treatments is scheduled for 2009. This proposal is to conduct an intensive, analytical harvest of the above-ground parts of 24 trees from each of the 12, 30 m diameter treatment plots (total of 288 trees) during June, July & August 2009. This above-ground harvest will be carefully coordinated with the below-ground harvest proposed by D.F. Karnosky et al. (2008 proposal to DOE). We propose to dissect harvested trees according to annual height growth increment and organ (main stem, branch orders, and leaves) for calculation of above-ground biomass production and allometric comparisons among aspen clones, species, and treatments. Additionally, we will collect fine root samples for DNA fingerprinting to quantify biomass production of individual aspen clones. This work will produce a thorough characterization of above-ground tree and stand growth and allocation above ground, and, in conjunction with the below ground harvest, total tree and stand biomass production, allocation, and allometry.

  11. Using Aspen to Teach Chromatographic Bioprocessing: A Case Study in Weak Partitioning Chromatography for Biotechnology Applications

    Science.gov (United States)

    Evans, Steven T.; Huang, Xinqun; Cramer, Steven M.

    2010-01-01

    The commercial simulator Aspen Chromatography was employed to study and optimize an important new industrial separation process, weak partitioning chromatography. This case study on antibody purification was implemented in a chromatographic separations course. Parametric simulations were performed to investigate the effect of operating parameters…

  12. Increased saccharification yields from aspen biomass upon treatment with enzymatically generated peracetic acid.

    Science.gov (United States)

    Duncan, Shona; Jing, Qing; Katona, Adrian; Kazlauskas, Romas J; Schilling, Jonathan; Tschirner, Ulrike; Aldajani, Waleed Wafa

    2010-03-01

    The recalcitrance of lignocellulosic biomass to enzymatic release of sugars (saccharification) currently limits its use as feedstock for biofuels. Enzymatic hydrolysis of untreated aspen wood releases only 21.8% of the available sugars due primarily to the lignin barrier. Nature uses oxidative enzymes to selectively degrade lignin in lignocellulosic biomass, but thus far, natural enzymes have been too slow for industrial use. In this study, oxidative pretreatment with commercial peracetic acid (470 mM) removed 40% of the lignin (from 19.9 to 12.0 wt.% lignin) from aspen and enhanced the sugar yields in subsequent enzymatic hydrolysis to about 90%. Increasing the amount of lignin removed correlated with increasing yields of sugar release. Unfortunately, peracetic acid is expensive, and concentrated forms can be hazardous. To reduce costs and hazards associated with using commercial peracetic acid, we used a hydrolase to catalyze the perhydrolysis of ethyl acetate generating 60-70 mM peracetic acid in situ as a pretreatment to remove lignin from aspen wood. A single pretreatment was insufficient, but multiple cycles (up to eight) removed up to 61.7% of the lignin enabling release of >90% of the sugars during saccharification. This value corresponds to a predicted 581 g of fermentable sugars from 1 kg of aspen wood. Improvements in the enzyme stability are needed before the enzymatically generated peracetic acid is a commercially viable alternative.

  13. Using user models in Matlab® within the Aspen Plus® interface with an Excel® link

    Directory of Open Access Journals (Sweden)

    Javier Fontalvo Alzate

    2014-07-01

    Full Text Available Process intensification and new technologies require tools for process design that can be integrated into well-known simulation software, such as Aspen Plus®. Thus, unit operations that are not included in traditional Aspen Plus software packages can be simulated with Matlab® and integrated within the Aspen Plus interface. In this way, the user can take advantage of all of the tools of Aspen Plus, such as optimization, sensitivity analysis and cost estimation. This paper gives a detailed description of how to implement this integration. The interface between Matlab and Aspen Plus is accomplished by sending the relevant information from Aspen Plus to Excel, which feeds the information to a Matlab routine. Once the Matlab routine processes the information, it is returned to Excel and to Aspen Plus. This paper includes the Excel and Matlab template files so the reader can implement their own simulations. By applying the protocol described here, a hybrid distillation-vapor permeation system has been simulated as an example of the applications that can be implemented. For the hybrid system, the effect of membrane selectivity on membrane area and reboiler duty for the partial dehydration of ethanol is studied. Very high selectivities are not necessarily required for an optimum hybrid distillation and vapor permeation system.

  14. Conifer expansion reduces the competitive ability and herbivore defense of aspen by modifying light environment and soil chemistry.

    Science.gov (United States)

    Calder, W John; Horn, Kevin J; St Clair, Samuel B

    2011-06-01

    Disturbance patterns strongly influence plant community structure. What remains less clear, particularly at a mechanistic level, is how changes in disturbance cycles alter successional outcomes in plant communities. There is evidence that fire suppression is resulting in longer fire return intervals in subalpine forests and that these lengthened intervals increase competitive interactions between aspen and conifer species. We conducted a field and greenhouse study to compare photosynthesis, growth and defense responses of quaking aspen and subalpine fir regeneration under light reductions and shifts in soil chemistry that occur as conifers increase in dominance. The studies demonstrated that aspen regeneration was substantially more sensitive to light and soil resource limitations than that of subalpine fir. For aspen, light reductions and/or shifts in soil chemistry limited height growth, biomass gain, photosynthesis and the production of defense compounds (phenolic glycosides and condensed tannins). Biomass gain and phenolic glycoside concentrations were co-limited by light reduction and changes in soil chemistry. In contrast, subalpine fir seedlings tended to be more tolerant of low light conditions and showed no sensitivity to changes in soil chemistry. Unlike aspen, subalpine fir increased its root to shoot ratio on conifer soils, which may partially explain its maintenance of growth and defense. The results suggest that increasing dominance of conifers in subalpine forests alters light conditions and soil chemistry in a way that places greater physiological and growth constraints on aspen than subalpine fir, with a likely outcome being more successful recruitment of conifers and losses in aspen cover.

  15. Effects of elevated atmospheric CO2 and/or O3 on intra- and interspecific competitive ability of aspen.

    Science.gov (United States)

    Kubiske, M E; Quinn, V S; Marquardt, P E; Karnosky, D F

    2007-03-01

    Three model communities of trembling aspen (monoculture, and mixed with either paper birch or sugar maple) were grown for seven years in elevated atmospheric CO(2) and O(3) using Free Air CO(2) Enrichment (FACE) technology. We utilized trends in species' importance, calculated as an index of volume growth and survival, as indications of shifting community composition. For the pure aspen communities, different clones emerged as having the highest change in relative importance values depending on the pollutant exposure. In the control and elevated CO(2) treatments, clone 42E was rapidly becoming the most successful clone while under elevated O(3), clone 8 L emerged as the dominant clone. In fact, growth of clone 8 L was greater in the elevated O(3) treatment compared to controls. For the mixed aspen-birch community, importance of aspen and birch changed by - 16 % and + 62 %, respectively, in the controls. In the treatments, however, importance of aspen and birch changed by - 27 % and + 87 %, respectively, in elevated O(3), and by - 10 % and + 45 %, respectively, in elevated CO(2). Thus, the presence of elevated O(3) hastened conversion of stands to paper birch, whereas the presence of elevated CO(2) delayed it. Relative importance of aspen and maple changed by - 2 % and + 3 %, respectively, after seven years in the control treatments. But in elevated O(3), relative importance of aspen and maple changed by - 2 % and + 5 %, respectively, and in elevated CO(2) by + 9 and - 20 %, respectively. Thus, elevated O(3) slightly increases the rate of conversion of aspen stands to sugar maple, but maple is placed at a competitive disadvantage to aspen under elevated CO(2).

  16. Variation of Leaf Characteristics in Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    An investigation was conducted to determine the extent of variations among nine provenances of Populus tomentosa Carr. in terms of leaf characteristics. A total of 263 accessions were studied under field conditions in the National Gene Bank of P. tomentosa in 2003. All of the accessions were characterized by 17 indices from 1 to 2-dimension constructions. Variance analysis of all characteristics showed that there were significant differences among the nine provenances and among individuals within each provenance. This study reveals that the evaluated germplasm appears to have a wide genetic base and high potential for further genetic improvements and it also indicates that abundant gene resources of P. tomentosa have been collected and preserved in the National Gene Bank.

  17. [Application of Populus Nigra preparations at experimental parodontitis].

    Science.gov (United States)

    Kipiani, N V; Kuchukhidze, Dzh K; Chichua, Z Dzh; Kipiani, V A; Datunashvili, I V

    2007-09-01

    Severe oxidative stress, developed under experimental periodontitis is accompanied by disturbances in mitochondrial respiration in tissue cells of gingiva, membrane damage and release of Fe(2+) and Mn(2+), leading to the worsening of inflammation process and gingival tissue necrosis. Reduction of free nitric oxide in gingival tissue appeared to be characteristic for experimental parodontitis: decreases local immunity, antimicrobial resistance, and tissue regeneration, disturbs blood supply and tissue trophism, which forwards important role in deepening of inflammation process and wasting of gingival tissue. Application of preparations derived from black poplar (Populus Nigra) gemma standardizes mitochondrial respiration, reduces presentation of inflammation, and considerably improves EPR-spectrum of gingival tissue. Though the complete normalization is not achieved--hazard of peroxidation still remains, the applied preparations, due to their strong anti- oxidative and anti-inflammatory activities is as an effective and rehabilitative means to tackle gingivitis and peiodontitis.

  18. Populus euphratica, a Tolerant Model but Endangered Arborescent Species

    Institute of Scientific and Technical Information of China (English)

    Gu Ruisheng; Pei Dong

    2005-01-01

    @@ Populus euphratica is a most tolerant arborescent species to abiotic stress. It can adapt to extreme conditions, ranging from flood to atmosphere extremely dry, hot from + 54 ℃ to - 45 ℃, and from normal soil to the soil with very high salt concentration ( to 2 ~5%) although being a non-halophyte. However, the natural stands of P. euphratica have been shrinking tremendously for the past decades and some populations are facing the fate of extinction. The preservation of existing resources should be carried out as a burning issue. In parallel, P. euphratica could be taken as a model plant to explore the molecular mechanism of abiotic-stress tolerance and to exploit its tolerant genes due to its smaller genome and easy molecular manipulation. The measures for preservation, germ-plasma exploitation, tolerance mechanism exploration and resource utilization were also discussed in this paper.

  19. RAPD markers related to sex locus in Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    Wanwei HOU; Junfeng FAN; Feimei ZHOU; Shufang ZHAO

    2009-01-01

    By using the methods of random amplified polymorphic DNA (RAPD) and bulked segregate analysis (BSA), we identified markers that are linked to the sex determination in the dioecious Populus tomentosa. Male and female bulks were created through rough mixing equal amounts of its five individual DNA. A total of 88 primers were screened. Twelve primers produced clear patterns with at least one band that appeared to be polymorphic between the two bulks. Subsequently, five male and female individuals were analyzed with those 12 primers, and only S60 (ACCCGGTCAC) could generate a common 1800bp DNA fragment in all five male individuals and male pool but not in any female individuals. It can be concluded that the gender of P. tomentosa is most likely connected to the S60-1800bp DNA fragment and RAPD markers. S60, therefore, can be used for selecting the gender of P. tomentosa.

  20. Establishment of cell suspension line of Populus tomentosa Carr

    Institute of Scientific and Technical Information of China (English)

    YAO Na; ZHANG Zhi-yi; AN Xin-min; YANG Kai

    2008-01-01

    Leaves of fine Populus tomentosa genotype TC152 were used as explants to establish cell suspension lines. The effects of plant growth regulators on callus induction and establishment of cell suspension lines were studied. The callus induction rate was the highest on a MS solid medium supplemented with 1.0 mg·L-1 2,4-D. A cell suspension line could be obtained by inoculating calli which were not subeultured into a MS liquid medium supplemented with 1.5 mg·L-1 2,4-D. The best subculture medium was MS+ 0.8 mg·L-1 2,4-D + 30 g·L-1 sucrose with a subculture cycle of seven days.

  1. Cross Breeding of Populus and Its Hybrids for Cold Resistance

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Populus tomentosa was crossed with P. tremuloidis, P. grandidentata, P. alba × P. grandidentata and P. alba × Ulmus pumila in order to maintain its rapid growth and high wood quality and improve its resistance to cold. Two methods were used to increase the germination rate from 1.5% to 41.1% and the remaining rate from 1.7% to 44.2%. Forty crossing combinations were conducted and 2 744 hybrid seedlings were obtained. MX4 × P. grandidentata (G-1-58), MX3 × P. tremuloidis (T-44-60), MX2 × P. tremuloidis (l-13-87-37) and MX2 × (P. alba × P. grandidentata) were regarded as superior combinations after analysis and selection. Thirty seedlings of these combinations and 11 triploid seedlings identified by counting their chromosomes were selected as super plants.

  2. Stress-responsive hydroxycinnamate glycosyltransferase modulates phenylpropanoid metabolism in Populus.

    Science.gov (United States)

    Babst, Benjamin A; Chen, Han-Yi; Wang, Hong-Qiang; Payyavula, Raja S; Thomas, Tina P; Harding, Scott A; Tsai, Chung-Jui

    2014-08-01

    The diversity of phenylpropanoids offers a rich inventory of bioactive chemicals that can be exploited for plant improvement and human health. Recent evidence suggests that glycosylation may play a role in the partitioning of phenylpropanoid precursors for a variety of downstream uses. This work reports the functional characterization of a stress-responsive glycosyltransferase, GT1-316 in Populus. GT1-316 belongs to the UGT84A subfamily of plant glycosyltransferase family 1 and is designated UGT84A17. Recombinant protein analysis showed that UGT84A17 is a hydroxycinnamate glycosyltransferase and able to accept a range of unsubstituted and substituted cinnamic and benzoic acids as substrates in vitro. Overexpression of GT1-316 in transgenic Populus led to plant-wide increases of hydroxycinnamoyl-glucose esters, which were further elevated under N-limiting conditions. Levels of the two most abundant flavonoid glycosides, rutin and kaempferol-3-O-rutinoside, decreased, while levels of other less abundant flavonoid and phenylpropanoid conjugates increased in leaves of the GT1-316-overexpressing plants. Transcript levels of representative phenylpropanoid pathway genes were unchanged in transgenic plants, supporting a glycosylation-mediated redirection of phenylpropanoid carbon flow as opposed to enhanced phenylpropanoid pathway flux. The metabolic response of N-replete transgenic plants overlapped with that of N-stressed wild types, as the majority of phenylpropanoid derivatives significantly affected by GT1-316 overexpression were also significantly changed by N stress in the wild types. These results suggest that UGT84A17 plays an important role in phenylpropanoid metabolism by modulating biosynthesis of hydroxycinnamoyl-glucose esters and their derivatives in response to developmental and environmental cues.

  3. Carbon gain and bud physiology in Populus tremuloides and Betula papyrifera grown under long-term exposure to elevated concentrations of CO{sub 2} and O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Riikonen, J. [Kuopio Univ., Kuopio (Finland). Dept. of Ecology and Environmental Science; Kets, K.; Sober, A. [Tartu Univ., Tartu (Estonia). Inst. of Botany and Ecology; Darbah, J.; Karnosky, D.F. [Michigan Technical Univ., Houghton, MI (United States). School of Forest Resources and Environmental Science; Oksanen, E. [Joensuu Univ., Joensuu (Finland). Faculty of Biosciences; Vapaavuori, E. [Finnish Forest Research Inst., Suonenjoki (Finland). Suonenjoki Research Inst.; Kubiske, M.E.; Nelson, N. [USDA Forest Service, Rhinelander, WI (United States). Forestry Sciences Laboratory

    2008-02-15

    Elevated carbon dioxide (CO{sub 2}) enhances photosynthesis by increasing carboxylation rates and decreasing the rate of photorespiration. While elevated CO{sub 2} has the potential to increase frost hardiness in trees by increasing bud size and concentrations of cryoprotective soluble sugars in overwintering organs, little is known about the effects of elevated CO{sub 2} on late-season photosynthesis. This study examined 3 trembling aspen (Populus tremuloides) clones and 3 paper birch (Betula papyrifera) grown at a site with elevated CO{sub 2} and ozone (O{sub 3}) applied singly and in combination. Gas exchange was studied throughout the eighth growing season. The study also examined specific leaf area and size in September and final size, carbohydrate, carbon (C), nitrogen (N) and water concentrations in November. The timing of leaf abscission was also studied, as well as bud burst and the development of leaf area index the following Spring. Results of the study showed that net photosynthesis was enhanced by between 49 and 73 per cent with elevated levels of CO{sub 2}, and decreased by between 13 and 30 per cent with elevated O{sub 3}. Elevated CO{sub 2} delayed leaf abscission and increased the ratio of monosaccharides in aspen buds. Total carbon concentrations in overwintering buds were unaffected by the treatments. It was concluded that elevated CO{sub 2} ameliorated the effects of elevated O{sub 2}, but had the potential to alter C metabolism of overwintering buds. 50 refs., 5 tabs., 6 figs.

  4. Effects of Fertilization Treatments on Plantation Growth of Triploid Clones in Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    Wang Lixian; Liu Yong; Zhang Zhiyi

    2003-01-01

    With four clones of triploid Populus tomentosa as materials, the effects of fertilization treatment on growth and physiological characters in terms of leaf nitrogen content, phosphorous content, potassium content, net photosynthetic rate, transpiration rate, water utilization efficiency and chlorophyll content have been studied. Compared with the general fertilizer as a control, the long-effect fertilizer, especially for Populus, produce more favorable results, for P. tomentosa on sandy land.

  5. Ozone-induced changes in carotenoids and chlorophylls in three Populus clones

    OpenAIRE

    Keski-Saari, Sarita; Dumont, Jennifer; Keinänen, Markku; Kontunen-Soppela, Sari; Oksanen, Elina; Le Thiec, Didier

    2011-01-01

    Ozone is a phytotoxic air pollutant causing oxidative stress. We studied the effect of ozone on carotenoids, chlorophylls and polyisoprenoid alcohols in three euramerican poplar clones (Populus deltoides x Populus nigra: 'Carpaccio', 'Cima' and 'Robusta'). Poplars originating from cuttings were grown for 6 weeks and exposed to ozone in fumigation chambers (120 ppb each day for 13h). Leaf samples were collected 2, 4, 11, 15 and 17 days after the start of ozone treatment. Chemical analyses were...

  6. Glycosylation-mediated phenylpropanoid partitioning in Populus tremuloides cell cultures

    OpenAIRE

    2009-01-01

    Abstract Background Phenylpropanoid-derived phenolic glycosides (PGs) and condensed tannins (CTs) comprise large, multi-purpose non-structural carbon sinks in Populus. A negative correlation between PG and CT concentrations has been observed in several studies. However, the molecular mechanism underlying the relationship is not known. Results Populus cell cultures produce CTs but not PGs under normal conditions. Feeding salicyl alcohol resulted in accumulation of salicins, the simplest PG, in...

  7. 利用Aspen Plus 7.3进行严格精馏过程模拟%The Simulation of Strict Distillation Process Using Aspen Plus 7.3

    Institute of Scientific and Technical Information of China (English)

    薛科创

    2014-01-01

    化工过程模拟是通过计算机对化工生产过程的再现,由于计算量大,必须通过相应的化工模拟软件来实现.Aspen Plus,尤其是Aspen Plus 7.3,由于其计算精确、运行速度快,成为化工设计者的首选软件.本文通过介绍利用Aspen Plus 7.3进行严格精馏模拟,说明了严格精馏模拟的应用范围以及利用Aspen Plus 7.3进行严格精馏模拟的方法.

  8. Aspen Plus Software Applies to Technological Transformation of Trichlorosilane Synthesis%Aspen Plus软件在三氯氢硅低压合成技术改造中的应用

    Institute of Scientific and Technical Information of China (English)

    刘兴平

    2014-01-01

    利用化工模拟软件Aspen Plus对三氯氢硅合成装置进行全流程模拟,并在此基础上完成了该系统的技术改造.Aspen Plus软件为系统工艺改造提供了可靠的基础数据,大大提高了改造的成功性.

  9. How to Create, Modify, and Interface Aspen In-House and User Databanks for System Configuration 2:

    Energy Technology Data Exchange (ETDEWEB)

    Camp, D W

    2000-10-27

    The goal of this document is to provide detailed instructions to create, modify, interface, and test Aspen User and In-House databanks with minimal frustration. The level of instructions are aimed at a novice Aspen Plus simulation user who is neither a programming nor computer-system expert. The instructions are tailored to Version 10.1 of Aspen Plus and the specific computing configuration summarized in the Title of this document and detailed in Section 2. Many details of setting up databanks depend on the computing environment specifics, such as the machines, operating systems, command languages, directory structures, inter-computer communications software, the version of the Aspen Engine and Graphical User Interface (GUI), and the directory structure of how these were installed.

  10. How to Create, Modify, and Interface Aspen In-House and User Databanks for System Configuration 1:

    Energy Technology Data Exchange (ETDEWEB)

    Camp, D W

    2000-10-27

    The goal of this document is to provide detailed instructions to create, modify, interface, and test Aspen User and In-House databanks with minimal frustration. The level of instructions are aimed at a novice Aspen Plus simulation user who is neither a programming nor computer-system expert. The instructions are tailored to Version 10.1 of Aspen Plus and the specific computing configuration summarized in the Title of this document and detailed in Section 2. Many details of setting up databanks depend on the computing environment specifics, such as the machines, operating systems, command languages, directory structures, inter-computer communications software, the version of the Aspen Engine and Graphical User Interface (GUI), and the directory structure of how these were installed.

  11. Influence of Lateral Flow on the Predisposition of Aspen Mortality during Drought

    Science.gov (United States)

    Tai, X.; Mackay, D. S.; Anderegg, W.; Sperry, J. S.

    2014-12-01

    Lateral subsurface flow can be critical to understanding the spatial soil moisture availability to plants, and when, where, and how drought are influencing individual plants. The concentration of intensive aspen damage in certain hillslopes with higher temperature and lower soil moisture suggests that soil augmentation/reduction from lateral redistribution could help explain the survivability of some aspen through its influence on soil water availability during drought. It remains unclear how lateral water redistribution helps to limit hydraulic impairment of aspen located in different topographic positions during a drought event. This study employed an integrated ecohydrology model, TREES, combining plant-water balance and canopy physiology, to examine the potential effects of lateral flow on hydraulic and metabolic performance of aspen, by exposing trees to a set of soil water conditions associated with different levels of water stress. Sap flux, soil moisture, meteorological and plant hydraulic data from aspen trees in Colorado that died (SAD) and those that lived were used to parameterize the model. Our goal was to quantify the extent to which lateral flow explained sudden aspen dieback. The results indicate that the predisposition of tree mortality is related to the level of soil water augmentation. A reduction of 30% soil water content could introduce 21.55% increase in the loss of hydraulic conductivity (PLC), 23.6% loss in canopy transpiration, 21.7% loss in GPP. It would also cause the frequency of greater than 50% PLC to increase from 42.1% of the time to 51% of the time, and the frequency of hitting the 88% PLC pressure to increase from 11% to 14% of the time. On the other hand, an augment of 30% soil water content could introduce 20.2% reduction in PLC, 16.4% gain in canopy transpiration, 16.5% gain in GPP. The frequency of greater than 50% PLC is reduced to 31% of the time and the frequency of hitting the 88% PLC pressure is reduced to 6% of the time

  12. Technological Simulation and Optimizing Design of Atmospheric Distillation Column by ASPEN PLUS Software%ASPEN PLUS模拟常压塔装置设计优化

    Institute of Scientific and Technical Information of China (English)

    刘呈军

    2013-01-01

    本文采用ASPEN PLUS软件对大庆原油常压塔部分操作工况进行了工艺模拟计算.模拟结果表明,实际操作中的塔操作条件、总物料平衡、产品质量等指标与工艺设计吻合较好,为大型常压塔的设计选型提供了参考依据.

  13. 工业系统流程模拟利器--ASPEN PLUS%Introduction of a Useful Industrial Flowsheet Simulation Program, ASPEN PLUS

    Institute of Scientific and Technical Information of China (English)

    赵琛琛

    2003-01-01

    流程模拟软件的功效在于依托精确的模型、科学的计算方法对单元和系统进行计算和高效的优化设计.在已经开发成功的模拟软件中,ASPEN PLUS是比较先进的,在大型化工和热工系统模拟中更展现了它的优势.概括介绍了这款软件的功能和使用方法.

  14. Process simulation for the rectification of vinyl chloride based on ASPEN PLUS%基于ASPEN PLUS的氯乙烯精馏过程的模拟

    Institute of Scientific and Technical Information of China (English)

    李群生; 刘阳

    2008-01-01

    应用ASPEN PLUS化工模拟系统中的RADFRAC精馏模块对氯乙烯精馏中的高低沸塔进行模拟,模拟值与实际值基本吻合.讨论了回流比、进料位置、馏出比等参数对精馏的影响,获得了对氯乙烯精馏具有指导意义的相关工艺数据.

  15. Simulation analysis of distillation of dichloroethane by using ASPEN PLUS%二氯乙烷精馏过程的ASPEN PLUS模拟分析

    Institute of Scientific and Technical Information of China (English)

    钱启蒙

    2015-01-01

    利用化工流程模拟软件Aspen Plus对二氯乙烷(EDC)精制单元进行模拟研究.针对工艺流程改变后EDC纯度不达标的问题,提出了新的模拟优化方案.模拟结果表明:通过将脱重塔部分出料重新送入脱轻塔,改变脱轻塔进料组成,能有效提高EDC纯度.

  16. Lignin depolymerization/repolymerization and its critical role for delignification of aspen wood by steam explosion.

    Science.gov (United States)

    Li, Jiebing; Henriksson, Gunnar; Gellerstedt, Göran

    2007-11-01

    Steam explosion is an important process for the fractionation of biomass components. In order to understand the behaviour of lignin under the conditions encountered in the steam explosion process, as well as in other types of steam treatment, aspen wood and isolated lignin from aspen were subjected to steam treatment under various conditions. The lignin portion was analyzed using NMR and size exclusion chromatography as major analytical techniques. Thereby, the competition between lignin depolymerization and repolymerization was revealed and the conditions required for these two types of reaction identified. Addition of a reactive phenol, 2-naphthol, was shown to inhibit the repolymerization reaction strongly, resulting in a highly improved delignification by subsequent solvent extraction and an extracted lignin of uniform structure.

  17. Standardized Competencies for Parenteral Nutrition Order Review and Parenteral Nutrition Preparation, Including Compounding: The ASPEN Model.

    Science.gov (United States)

    Boullata, Joseph I; Holcombe, Beverly; Sacks, Gordon; Gervasio, Jane; Adams, Stephen C; Christensen, Michael; Durfee, Sharon; Ayers, Phil; Marshall, Neil; Guenter, Peggi

    2016-08-01

    Parenteral nutrition (PN) is a high-alert medication with a complex drug use process. Key steps in the process include the review of each PN prescription followed by the preparation of the formulation. The preparation step includes compounding the PN or activating a standardized commercially available PN product. The verification and review, as well as preparation of this complex therapy, require competency that may be determined by using a standardized process for pharmacists and for pharmacy technicians involved with PN. An American Society for Parenteral and Enteral Nutrition (ASPEN) standardized model for PN order review and PN preparation competencies is proposed based on a competency framework, the ASPEN-published interdisciplinary core competencies, safe practice recommendations, and clinical guidelines, and is intended for institutions and agencies to use with their staff.

  18. Aspen Plus软件在工业上的应用

    Institute of Scientific and Technical Information of China (English)

    牛毓

    2014-01-01

    Aspen Plus软件是一款重要的工流程模拟软件,该软件应用范围广泛,在传热领域、精馏领域以及化工领域等方面都有应用,尤其是在化工模拟领域应用最广。本文主要对Aspen Plus软件功能进行了介绍,介绍了该软件在工业上的应用情况,并重点介绍了其在化工行业的应用。

  19. THE FOREST-ATMOSPHERIC CARBON TRANSFER AND STORAGE-II (FACTS-II): ASPEN FACE PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    KARNOSKY,D.F.; HENDREY,G.; PREGITZER,K.; ISEBRANDS,J.G.

    1998-02-01

    The FACTS II (ASPEN FACE) infrastructure including 12 FACE [Free-Air Carbon dioxide Enrichment] rings, a central control facility, a central CO{sub 2} and O{sub 2} receiving and storage area, a central O{sub 3} generation system, and a dispensing system for CO{sub 2} and O{sub 3} was completed in 1997. The FACE rings were planted with over 10,000 plants (aspen, birch and maple). The entire system was thoroughly tested for both CO{sub 2} and O{sub 3} and was shown to be effective in delivering elevated CO{sub 2} and/or O{sub 3} on demand and at predetermined set points. The NCASI support to date has been extremely helpful in matching support for federal grants.

  20. The Forest-Atmospheric Carbon Transfer and Storage-II (FACTS-II): Aspen FACE project

    Energy Technology Data Exchange (ETDEWEB)

    Karnosky, D.F.; Pregitzer, K. [Michigan Technological Univ., Houghton, MI (United States). School of Forestry and Wood Products; Hendrey, G. [Brookhaven National Lab., Upton, NY (United States); Isebrands, J.G. [Forest Service, Rhinelander, WI (United States)

    1998-02-01

    The FACTS II (Aspen FACE) infrastructure including 12 FACE rings, a central control facility, a central CO{sub 2} and O{sub 3} receiving and storage area, a central O{sub 3} generation system, and a dispensing system for CO{sub 2} and O{sub 3} was completed in 1997. The FACE rings were planted with over 10,000 plants (aspen, birch and maple). The entire system was thoroughly tested for both CO{sub 2} and O{sub 3} and was shown to be effective in delivering elevated CO{sub 2} and/or O{sub 3} on demand and at predetermined set points. The NCASI support to date has been extremely helpful in matching support for federal grants.

  1. Dicty_cDB: SHA231 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available RNA gene, partial sequence. 190 3e-97 3 AJ645166 |AJ645166.1 Populus tremula x P. tremuloides/Amanita muscar...ia mixed EST library EST, clone ptamabc210057a10. 188 7e-94 3 AJ643225 |AJ643225.1 Populus tremula x P. tremuloides/Amanita...ulus tremula x P. tremuloides/Amanita muscaria mixed EST library EST, clone ptama...e, partial sequence. 206 1e-93 3 AJ644039 |AJ644039.1 Populus tremula x P. tremuloides/Amanita muscaria mixe

  2. Genetic Augmentation of Syringyl Lignin in Low-lignin Aspen Trees, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Chung-Jui Tsai; Mark F. Davis; Vincent L. Chiang

    2004-11-10

    As a polysaccharide-encrusting component, lignin is critical to cell wall integrity and plant growth but also hinders recovery of cellulose fibers during the wood pulping process. To improve pulping efficiency, it is highly desirable to genetically modify lignin content and/or structure in pulpwood species to maximize pulp yields with minimal energy consumption and environmental impact. This project aimed to genetically augment the syringyl-to-guaiacyl lignin ratio in low-lignin transgenic aspen in order to produce trees with reduced lignin content, more reactive lignin structures and increased cellulose content. Transgenic aspen trees with reduced lignin content have already been achieved, prior to the start of this project, by antisense downregulation of a 4-coumarate:coenzyme A ligase gene (Hu et al., 1999 Nature Biotechnol 17: 808- 812). The primary objective of this study was to genetically augment syringyl lignin biosynthesis in these low-lignin trees in order to enhance lignin reactivity during chemical pulping. To accomplish this, both aspen and sweetgum genes encoding coniferaldehyde 5-hydroxylase (Osakabe et al., 1999 PNAS 96: 8955-8960) were targeted for over-expression in wildtype or low-lignin aspen under control of either a constitutive or a xylem-specific promoter. A second objective for this project was to develop reliable and cost-effective methods, such as pyrolysis Molecular Beam Mass Spectrometry and NMR, for rapid evaluation of cell wall chemical components of transgenic wood samples. With these high-throughput techniques, we observed increased syringyl-to-guaiacyl lignin ratios in the transgenic wood samples, regardless of the promoter used or gene origin. Our results confirmed that the coniferaldehyde 5-hydroxylase gene is key to syringyl lignin biosynthesis. The outcomes of this research should be readily applicable to other pulpwood species, and promise to bring direct economic and environmental benefits to the pulp and paper industry.

  3. Aquatic ecosystem response to timber harvesting for the purpose of restoring aspen.

    Science.gov (United States)

    Jones, Bobette E; Krupa, Monika; Tate, Kenneth W

    2013-01-01

    The removal of conifers through commercial timber harvesting has been successful in restoring aspen, however many aspen stands are located near streams, and there are concerns about potential aquatic ecosystem impairment. We examined the effects of management-scale conifer removal from aspen stands located adjacent to streams on water quality, solar radiation, canopy cover, temperature, aquatic macroinvertebrates, and soil moisture. This 8-year study (2003-2010) involved two projects located in Lassen National Forest. The Pine-Bogard Project consisted of three treatments adjacent to Pine and Bogard Creeks: (i) Phase 1 in January 2004, (ii) Phase 2 in August 2005, and (iii) Phase 3 in January 2008. The Bailey Project consisted of one treatment adjacent to Bailey Creek in September 2006. Treatments involved whole tree removal using track-laying harvesters and rubber tire skidders. More than 80% of all samples analyzed for NO₃-N, NH₄-N, and PO₄-P at Pine, Bogard, and Bailey Creeks were below the detection limit, with the exception of naturally elevated PO₄-P in Bogard Creek. All nutrient concentrations (NO₃-N, NH₄-N, PO₄-P, K, and SO₄-S) showed little variation within streams and across years. Turbidity and TSS exhibited annual variation, but there was no significant increase in the difference between upstream and downstream turbidity and TSS levels. There was a significant decrease in stream canopy cover and increase in the potential fraction of solar radiation reaching the streams in response to the Pine-Bogard Phase 3 and Bailey treatments; however, there was no corresponding increase in stream temperatures. Macroinvertebrate metrics indicated healthy aquatic ecosystem conditions throughout the course of the study. Lastly, the removal of vegetation significantly increased soil moisture in treated stands relative to untreated stands. These results indicate that, with careful planning and implementation of site-specific best management practices

  4. Aquatic ecosystem response to timber harvesting for the purpose of restoring aspen.

    Directory of Open Access Journals (Sweden)

    Bobette E Jones

    Full Text Available The removal of conifers through commercial timber harvesting has been successful in restoring aspen, however many aspen stands are located near streams, and there are concerns about potential aquatic ecosystem impairment. We examined the effects of management-scale conifer removal from aspen stands located adjacent to streams on water quality, solar radiation, canopy cover, temperature, aquatic macroinvertebrates, and soil moisture. This 8-year study (2003-2010 involved two projects located in Lassen National Forest. The Pine-Bogard Project consisted of three treatments adjacent to Pine and Bogard Creeks: (i Phase 1 in January 2004, (ii Phase 2 in August 2005, and (iii Phase 3 in January 2008. The Bailey Project consisted of one treatment adjacent to Bailey Creek in September 2006. Treatments involved whole tree removal using track-laying harvesters and rubber tire skidders. More than 80% of all samples analyzed for NO₃-N, NH₄-N, and PO₄-P at Pine, Bogard, and Bailey Creeks were below the detection limit, with the exception of naturally elevated PO₄-P in Bogard Creek. All nutrient concentrations (NO₃-N, NH₄-N, PO₄-P, K, and SO₄-S showed little variation within streams and across years. Turbidity and TSS exhibited annual variation, but there was no significant increase in the difference between upstream and downstream turbidity and TSS levels. There was a significant decrease in stream canopy cover and increase in the potential fraction of solar radiation reaching the streams in response to the Pine-Bogard Phase 3 and Bailey treatments; however, there was no corresponding increase in stream temperatures. Macroinvertebrate metrics indicated healthy aquatic ecosystem conditions throughout the course of the study. Lastly, the removal of vegetation significantly increased soil moisture in treated stands relative to untreated stands. These results indicate that, with careful planning and implementation of site-specific best management

  5. Methods to inventory and strip thin in dense stands of aspen root suckers

    Directory of Open Access Journals (Sweden)

    Headlee WL

    2015-10-01

    Full Text Available Aspen and their hybrids have demonstrated high biomass productivity and can produce abundant regeneration in the form of root suckers. This makes aspen particularly intriguing for bio-energy production, because replanting costs can be avoided and additional biomass can be obtained by thinning the regenerating stands. Mechanical strip thinning (removal of stems in parallel strips has been proposed as a fast and efficient method for capturing biomass that would otherwise be lost to mortality in such stands. However, determining the appropriate width for the residual rows is challenging, due to the difficulty of conducting inventories with traditional sampling tools and the variability in gap sizes between root suckers in the residual rows. In this study, we describe the development and testing of a simple inventory tool that may be used to conduct either fixed-area or variable-radius sampling in these stands. Also described is the development and testing of an equation that uses such inventory data along with Poisson distribution theory to predict the size of the largest gap between root suckers within residual rows, which in turn can be used to inform strip thinning operations. Based on the promising results of our limited tests, we encourage further evaluation of these methods with regeneration from planted and natural aspen stands, as well as other root suckering species.

  6. Phosphate removal by refined aspen wood fiber treated with carboxymethyl cellulose and ferrous chloride.

    Science.gov (United States)

    Eberhardt, Thomas L; Min, Soo-Hong; Han, James S

    2006-12-01

    Biomass-based filtration media are of interest as an economical means to remove pollutants and nutrients found in stormwater runoff. Refined aspen wood fiber samples treated with iron salt solutions demonstrated limited capacities to remove (ortho)phosphate from test solutions. To provide additional sites for iron complex formation, and thereby impart a greater capacity for phosphate removal, a fiber pretreatment with an aqueous solution of a non-toxic anionic polymer, carboxymethyl cellulose (CMC), was evaluated. Problems with excessive viscosities during the screening of commercially available CMC products led to the selection of an ultra low viscosity CMC product that was still usable at a 4% concentration in water. Soxhlet extractions of chipped aspen wood and refined aspen wood fiber samples showed a higher extractives content for the refined material. Analysis of these extracts by FTIR spectroscopy suggested that the higher extractives content for the refined material resulted from the fragmentation of cell wall polymers (e.g., lignin, hemicelluloses) normally insoluble in their native states. Spectroscopic analysis of CMC and ferrous chloride treated fibers showed that the complex formed was sufficiently stable to resist removal during subsequent water washes. Equilibrium sorption data, which fit better with a Freundlich isotherm model than a Langmuir isotherm model, showed that phosphate removal could be enhanced by the CMC pretreatment. Results suggest that the process outlined may provide a facile means to improve the phosphate removal capacity of biomass-based stormwater filtration media.

  7. SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    Eric C. Xu; Yajun Zhou

    2004-01-01

    In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes.The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

  8. SYNERGISTIC EFFECTS BETWEEN BIRCH CHEMICAL MECHANICAL PULPS AND ASPEN BLEACHED KRAFT PULP

    Institute of Scientific and Technical Information of China (English)

    EricC.Xu; YajunZhou

    2004-01-01

    In this investigation, two different grades of birch chemical mechanical (P-RC APMP) pulps and aspen market bleached kraft pulp were compared by low consistency refining of the pulps separately and in different combinations. In addition, the separately refined pulps were also combined to compare with the pulps from the co-refined pulp blend. The results showed that in both cases there were synergistic effects between the two types of pulps: adding the birch P-RC APMP pulp to the aspen kraft pulp improved pulp properties, and the resultant pulp blends had a higher fiber bonding strength (tensile and tensile energy absorption) than the sum of weighted contributions from the individual components. Understanding this synergistic effect between chemical mechanical (P-RC APMP) and kraft pulps can help to improve their applications and performances in various papermaking processes. The results also showed that introducing, at least up to certain percentage of, the birch P-RC APMP pulp into the aspen bleached kraft pulp not only improves optical and bulk properties, but also maintains or improves tensile strength, even though the P-RC APMP pulp used has lower tensile than the kraft pulp.

  9. EFFECT OF THERMAL TREATMENT ON THE CHEMICAL COMPOSITION AND MECHANICAL PROPERTIES OF BIRCH AND ASPEN

    Directory of Open Access Journals (Sweden)

    Duygu Kocaefe

    2008-05-01

    Full Text Available The high temperature treatment of wood is one of the alternatives to chemical treatment. During this process, the wood is heated to higher temperatures than those of conventional drying. The wood structure changes due to decomposition of hemicelluloses, ramification of lignin, and crystallization of cellulose. The wood becomes less hygroscopic. These changes improve the dimensional stability of wood, increase its resistance to micro-organisms, darken its color, and modify its hardness. However, wood also might loose some of its elasticity. Consequently, the heat treatment conditions have to be optimized. Therefore, it is important to understand the transformation of the chemical structure of wood caused by the treatment. In this study, the modification of the surface composition of the wood was followed with Fourier transform infrared spectroscopy (FTIR and inverse gas chromatography (IGC under different experimental conditions. The effect of maximum treatment temperatures on the chemical composition of Canadian birch and aspen as well as the correlations between their chemical transformation and different mechanical properties are presented. FTIR analysis results showed that the heat treatment affected the chemical composition of birch more compared to that of aspen. The results of IGC tests illustrated that the surfaces of the aspen and birch became more basic with heat treatment. The mechanical properties were affected by degradation of hemicellulose, ramification of lignin and cellulose crystallization.

  10. Aspen-Plus模拟在氟化工中的应用

    Institute of Scientific and Technical Information of China (English)

    谢青

    2015-01-01

    随着我国经济的快速发展,高新科技领域的不断进步,以及社会各领域间的广泛渗透交流,尤其是Aspen- Plus系统,化工领域的广泛应用,其极大的促进了化工行业生产力和生产效率的提高,为推动化工行业的健康可持续发展发挥关键作用。因Aspen- Plus系统,在生产装置优化等方面,具备优异的特性,因而当前其在化工行业的多个领域,如氟化工中得到了充分的应用,并取得了良好效果。本文将就Aspen- Plus模拟系统,当前在氟化工中应用情况进行详细分析。

  11. Dynamic Simulation Analysis on Steam Pipeline Net Based on ASPEN HYSYS%基于 ASPEN HYSYS对蒸汽管网动态模拟分析

    Institute of Scientific and Technical Information of China (English)

    张亮

    2015-01-01

    以大型化工项目蒸汽系统的设计为例,介绍了煤化工项目中蒸汽系统的重要性,利用ASPEN HYSYS 软件对超高压、高压和低压蒸汽管网的意外停车等工况进行动态模拟,分析当前设计的合理性,优化控制器的整定参数,为设计改进提供合理的动态数据。%Taking the design of steam system in the large-sized chemical project as an example, author has introduced the importance of steam system in the chemical project of coal, dynamic simulation has been made for working conditions of the unexpected shut-down and so on of super high pressure, high pressure and low pressure steam pipeline nets, using the ASPEN HYSYS software;author has analyzed the reasonability of present design, has opti-mized the setting parameters of the controller, so it provided the rational and dynamic data for improving the design.

  12. 基于ASPEN PLUS软件的甲烷化工艺模型%Simulation of methanation process based on ASPEN PLUS

    Institute of Scientific and Technical Information of China (English)

    何一夫

    2012-01-01

    利用ASPEN PLUS对煤制天然气的甲烷化工艺进行了流程模拟.模型模拟得到了替代天然气成分、反应器出口温度、循环比、分流率,揭示了循环比和分流率对反应器出口温度的影响.通过该模型,能够为工艺方案比选、优化设计提供模拟和预测.%The methanation process model is proposed and simulated by ASPEN PLUS software. The substitute natural gas composition, the reactor outlet temperature, the recycle ratio and the split ratio are obtained, which suggests the main influence of recycle ratio and the split ratio on the reactor outlet temperature. The model can simulate and predict the methanation process for process comparison and optimization design.

  13. Dicty_cDB: Contig-U13700-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ) Populus tremula x P. tremuloides/Amanita muscaria... 46 0.010 2 ( AC116305 ) Dictyostelium discoideum chro...93 1 ( CN650175 ) Eg_PSGRS_13C02_T7 Echinococcus granulosus protosc... 46 0.93 1 ( AJ643300 ) Populus tremula x P. tremuloides/Amanit

  14. 基于Aspen Plus的蒸汽透平网络模拟和优化%Simulation and optimization of steam turbine network with Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    马琳瑛; 赵亮; 李泽秋; 钱锋

    2012-01-01

    According to the unreasonable phenomena in the steam piping network of ethylene plant, the steam turbine network of the device is simulated and optimized by the chemical process software, Aspen Plus. The influence of operating condition change on turbine efficiency is discussed through simulation of the turbine, such as extraction steam flow, into steam temperature, exhaust steam pressure. Based on the results, the steam turbine network is simulated and optimized by particle swarm optimization through the interface toolkit MAP, while extraction steam flow for independent variable and the total into steam flow for target variables. Using intelligent algorithm, the defect of model's not easy to converge is avoided, which is caused by setting too much constraints as Design Regulations in Aspen Plus. The optimization results show that in the condition of meeting the same output power and the requirement of the other pipe networks, the steam consumption of supper-high-pressure (SS) could be reduced effectively by selecting the extraction capacity of every turbine reasonably. The turbine network optimized could decrease 0.6 ton SS consumption per hour.%针对乙烯装置蒸汽管网用能过程中存在的不合理现象,采用Aspen Plus化工流程软件对其中的蒸汽透平网络进行了模拟和优化.通过对单个透平的模拟,分析了透平抽汽量、进汽温度和排汽压力等操作条件的变化对透平效率的影响.在此基础上模拟了蒸汽透平网络,并以透平抽汽量为自变量、透平网络总进汽量为目标变量,通过MATLAB-Aspen Plus接口工具箱使用粒子群优化算法(PSO)对其进行操作参数优化.采用智能算法,避开了因在Aspen Plus中设置过多约束作为设计规定而导致模型不易收敛的不足;对于约束条件的处理,通过对不满足约束的粒子加以惩罚来实现.优化结果表明,在满足透平输出功率以及低等级管网蒸汽用量需求的前提下,通过合理分

  15. Usando modelos de usuario en matlab® en la interfaz de aspen plus® con excel® como puente

    OpenAIRE

    FONTALVO ALZATE, JAVIER

    2014-01-01

    El diseño de procesos intensificados y de nuevas tecnologías requiere de herramientas de simulación como Aspen Plus®. Sin embargo, las operaciones unitarias que no se incluyen en Aspen Plus pueden ser simuladas usando Matlab e integradas con la interfaz de Aspen Plus. De esta forma se pueden aprovechar todas la capacidades de Aspen plus como la optimización, el análisis de sensibilidad y la estimación de costos. Este artículo describe en detalle cómo implementar esta integración. La interfaz ...

  16. Genetic diversity in Populus nigra plantations from west of Iran

    Directory of Open Access Journals (Sweden)

    Afrooz Alimohamadi

    2012-11-01

    Full Text Available In order to adopt strategies for forest conservation and development,it is necessary to estimate the amount and distribution of genetic diversity in existing populations of poplar in Iran. In this study, the genetic diversity between eight stands of Populus nigra established in Kermanshah province was evaluated on the basis of molecular and morphological markers. To amplify microsatellite loci (WPMS09, WPMS16 and WPMS18, DNA extraction from young and fresh leaveswas done. Various conditions of the PCR assay were examined and to evaluate the morphological variation of the morphological characters leaves (consist of 19 traits were measured. In addition, height growth was measured, to evaluate the growth function of the stands in homogeneous conditions. Genetic diversity in termof polymorphic loci was 0%, because three investigated microsatellite loci were monomorphic. The total number of alleles for 3 microsatellite loci was 6 (na = 2, ne = 2, heo = 1, hee = 0.51. Genetic identity based on Nei was 100%, so genetic distance was 0%. The whole sampled trees represented the same thus the genotype. No significant differences between the mean values of all morphological characters and height growth were revealed. Observed genetic similarity gave indication that same ramets had been selected to plant in poplar plantation established in Kermanshah province.These results suggest the need for an initial evaluation of the genetic diversity in selected ramets for planting in plantation to avoid repetition.

  17. Lignin Characterization of Triploid Clones of Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    Jin Xiao-juan; Pu Jun-wen; Xie Yi-min; Takeshi Furuno; Liu Xin-yu

    2005-01-01

    In order to understand the structural characteristics of lignin in triploid clones ofPopulus tomentosa and its changes in the processes of pulping and bleaching, milled wood lignin (MWL), lignin carbohydrate complex (LCC) and the residual lignin from kraft pulp (KP) and sulfite pulp (SP) were isolated and analyzed by Fourier transform infrared (FTIR) spectrum and 13C nuclear magnetic resonance (NMR). The most diagnostic peaks were assigned and the differences were discussed. The spectral patterns reveal that triploid P. tomentosa shows the specific features of hardwood from temperate areas, but in the spectrum of FTIR, the strength ratio of A1270 cm-1 to A1226 cm-1 is 0.88, higher than the average of hardwood from temperate areas, which will make the lignin delignification more difficult during pulping and bleaching. The LCC from triploid P. tomentosa is mainly composed of xyloglucan and glucuronic acid, and other glucides have much lower ratio. In LCC FTIR, there are three peaks at 1 427, 1 329 and 1046 cm--1, indicating that both semi-cellulose and cellulose could exist in LCC, and that there might be relationships between cellulose and lignin. Compared with the residual lignin from KP and SP, the condensed structure in KP is more than that in SP.

  18. Construction of cDNA Library from Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Yu Guangjun; Wang Yiqin; Shen Xin

    2003-01-01

    In order to isolate and clone salt-tolerance involved genes of Populus euphratica, we constructed a cDNA library from salt-treated leaves of P. euphratica. In the experiment, double strand cDNA were synthesized by a beads-based method. The syntheses of the first strand and the second strand cDNA, adapter ligation and restriction reaction for releasing cDNA were all conducted on the beads. The double strand cDNA were released from magnetic beads by digestion with NotI, and cDNA fragments smaller than 500 bp and residual adapters were removed through cDNA size fractionation columns. Finally, double strand cDNA were directionally cloned intoλExcell vector. The results show that the primary titer of the cDNA library is 7.46×106 pfu per mL and the packaging efficiency reaches 1.47×107 recombinants per μg DNA. λDNA extracted from two clones of plaque were digested by EcoR I and NotI, both of the clones contained inserts larger than 900 bp. These results show that the cDNA library of salt-treated P. euphratica leaves has been successfully constructed.

  19. Establishment of in vitro culture of Populus euphratica Olivier

    Institute of Scientific and Technical Information of China (English)

    Zhao Peng; Dong Zhan-yuan; Sun Hong-bin; Zhao Ju-ying; Wang Hua-fang

    2006-01-01

    The purpose of our study was to establish a regeneration system for micropropagation of Populus euphratica Olivier. On the basis of an analysis of plant leaf mineral nutrients, a special medium was proposed, called MP2. In optimizing media for in vitro plant cultures including MS, B5 and MP2 media we employed hormones, auxin IAA, cytokine benzyladenine (BAP) and gibberellic acid (GA) in our factorial experiments on media. Adventitious shoots were derived from cuttings of adult plants taken from Xingjiang, west China, on selected media with MP2 + 0.5 mg.L-1 BA + 0.1 mg·L-1 NAA. The shoots were elongated on a medium with 0.25mg.L-1 BAP, 0.1 mg.L-1NAA and 2 mg·L-1 GA and were then rooted on a medium with 0.2-0.5 mg·L-1 IBA. All the media were incorporated with 30 g·L-1 sucrose and an adjusted pH at 6.3.

  20. Simulation of coal liquefaction process by developing user models on Aspen Plus platform%Aspen Plus用户模型技术的煤直接液化全流程模拟

    Institute of Scientific and Technical Information of China (English)

    单贤根; 常小瑞; 任琼; 江洪波; 翁惠新

    2014-01-01

    Based on six lumped kinetic model, this paper used the BFGS optimization algorithm to obtain kinetic constant of heating-up and isothermal stage of direct coal liquefaction process, and through regression of experimental data to get specific product composition for separation unit of direct coal liquefaction. Then the Aspen Plus user model of direct coal liquefaction was developed and integrated with the Aspen Plus software to achieve an entire process simulation of direct coal liquefaction process in Aspen Plus platform which can make the best use of its powerful databases and simulation calculation ability of separation processes. The calculation value of gas liquid equilibrium in high temperature and low temperature separators for reaction products agreed well with the experiment data. The entire process simulation in Aspen Plus platform can provide technical support for the optimization of direct coal liquefaction reaction and separation conditions.%基于六集总动力学模型,采用BFGS优化算法获得煤直接液化升温阶段和恒温阶段的反应动力学常数,同时通过试验数据回归得到用于煤直接液化分离单元的具体产品组成,并以此为基础开发了煤直接液化反应的Aspen Plus用户模型。在此基础上,将上述煤直接液化用户模型与Aspen Plus流程模拟软件集成在一起,充分利用Aspen Plus软件强大的性质数据库和分离过程模拟计算能力,最终实现了基于Aspen Plus平台的煤直接液化全流程模拟,模拟计算得到的煤直接液化反应产物在高温和低温分离器的气液相平衡数据与实验值较吻合。基于Aspen Plus的全流程模拟可以为煤直接液化反应和分离条件的优化选择提供技术参考。

  1. Applications of Aspen Plus in the Teaching of the Analysis and Synthesis for Chemical Engineering Process%Aspen plus在化工过程分析与合成课程教学中的应用

    Institute of Scientific and Technical Information of China (English)

    王磊; 李书珍; 刘卫民

    2012-01-01

    Analysis and Synthesis for Chemical Engineering Process was an important professional course for chemical majors,which was also a strong practical course.In the paper,dimethyl ether distillation column of the actual process of methanol to dimethyl ether was simulated and analyzed by Aspen Plus software.Students were familiarized with the use of Aspen Plus software in the process of simulation and analysis.In addition,the application of aspen Plus could help the following teaching of Chemical Process design.%化工过程分析与合成是化工类实践性非常强的专业基础课,精馏塔的实践教学是教学的重点和难点。文章采用Aspen Plus软件,以甲醇制二甲醚的实际工艺为案例,对二甲醚精馏塔进行模拟、分析,同时使学生熟悉Aspen Plus软件的使用,为后续化工设计打下基础。

  2. Genome-wide analysis of Aux/IAA and ARF gene families in Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    Kalluri, Udaya C [ORNL; DiFazio, Stephen P [West Virginia University; Brunner, A. [Virginia Polytechnic Institute and State University (Virginia Tech); Tuskan, Gerald A [ORNL

    2007-01-01

    Auxin/Indole-3-Acetic Acid (Aux/IAA) and Auxin Response Factor (ARF) transcription factors are key regulators of auxin responses in plants. A total of 35 Aux/IAA and 39 ARF genes were identified in the Populus genome. Comparative phylogenetic analysis revealed that the subgroups PoptrARF2, 6, 9 and 16 and PoptrIAA3, 16, 27 and 29 have differentially expanded in Populus relative to Arabidopsis. Activator ARFs were found to be two fold-overrepresented in the Populus genome. PoptrIAA and PoptrARF gene families appear to have expanded due to high segmental and low tandem duplication events. Furthermore, expression studies showed that genes in the expanded PoptrIAA3 subgroup display differential expression. The gene-family analysis reported here will be useful in conducting future functional genomics studies to understand how the molecular roles of these large gene families translate into a diversity of biologically meaningful auxin effects.

  3. Tissue Culture Technology for Populus × euramericana Hybrids: Effect of Genotype on in Vitro Regeneration

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to select a suitable genotype for the studies on genetic transformation, the difference among three genotypes (DN04-18, DN04-25 and DN04-26) of Populus × euramericana (Populus deltoides × P. nigra) in terms of shoot regeneration was investigated in this paper. An efficient in vitro micropropagation method was successfully established for genotype DN04-18. The high frequency shoot regeneration (90.0%) from leaf discs was obtained in genotype DN04-18 on the modified Murashige and Skoog (mMS) medium w...

  4. Aspen Plus与Visual C++混合编程在化工模拟中的应用%Application of Mixed Programming Based on Aspen Plus and Visual C++ in Chemical Simulation

    Institute of Scientific and Technical Information of China (English)

    蔡振兴

    2014-01-01

    化工过程模拟软件Aspen Plus在化工流程的设计、校核方面得到了广泛的应用,显著提高了化工工艺流程设计、校核的效率和水平.Aspen Plus支持ActiveX自动控制技术,并符合CAPE-OPEN接口标准.借助Visual C++编程环境,实现了对Aspen Plus数据库的调用、单元模块的开发、以及与水力学软件的集成.

  5. 运用ASPEN B-JAC 设计管壳式换热器%Design and Optimize Tube/Shell Heat Exchanger by Aspen B-jac

    Institute of Scientific and Technical Information of China (English)

    周奇

    2010-01-01

    描述了运用ASPEN B-JAC换热器计算软件进行管壳式换热器设计的步骤,讨论了换热器管程壳程优化设计的要点以及利用ASPEN B-JAC进行换热器设计优化过程中应注意的问题,为管壳式换热器的优化设计提供了参考.

  6. The Application of Aspen Plus in the Design of Distillation Column%流程模拟软件Aspen Plus在精馏塔设计中的应用

    Institute of Scientific and Technical Information of China (English)

    李峰; 赵新堂; 万宝锋

    2014-01-01

    The simple design and rigorous accounting on the distillation column has been performed by Aspen Plus in this paper. Also, the analysis of the influence factors on the design of distillation column was completed. In addition, the economic accounting of distillation column was discussed preliminarily.%以Aspen Plus流程模拟软件对精馏塔进行了简捷设计和严格核算,对精馏塔设计的影响因素进行了分析,并对精馏塔的经济核算进行了初步说明。

  7. Aspen Plus在化工设计物料衡算中的应用分析

    Institute of Scientific and Technical Information of China (English)

    茅慧

    2015-01-01

    化工领域中最关键的基础内容就是化工设计,随着社会的进步和科学技术的发展,传统的化工设计方式逐渐被Aspen Plus软件所替代,在化工设计领域中发挥着重要作用.本文主要阐述了Aspen Plus的概念,并对其在化工设计发挥的作用进行探究,分析了Aspen Plus在化工设计物料衡算中的应用,以期更加透彻的分析化工过程连续生产时的物料衡算,进一步提高化工设计效果.

  8. Aspen height, stem-girth and survivorship in an area of high ungulate use

    Science.gov (United States)

    Keigley, R.B.; Frisina, M.R.

    2008-01-01

    An increase in ungulate population size potentially exposes aspen suckers, saplings, and trees to increased use. This study examined how stem height and girth influenced the selection of stems by ungulates for browsing, rubbing, and gnawing, and reconstructed the history of ungulate use for the study area. Transects were run through each of three aspen clones growing in southwestern Montana to determine height, circumference, and the surface area from which bark was totally and partially removed by rubbing and gnawing. Stems 20-250 cm tall were browsed. Stems 2-13 cm diameter were preferentially selected for rubbing and gnawing. The area of totally removed bark on dead saplings was twice the area of removed bark on live stems of similar diameter, suggesting that bark removal played a major role in the death of some stems. Based on an analysis of stem height and age, ungulate browsing was inferred to have increased from a light-to-moderate level to an intense level in 1991. The depth of scars was used to date scarring events. An increase in rubbing and gnawing was determined to have occurred about 1985. We concluded that elk were primarily responsible for the observed impacts. The combined effect of rubbing, gnawing, and browsing affects a broader span of ages compared to the effect of browsing alone. If prescribed fire is used to rejuvenate aspen stands, the resulting young stems should be protected from heavy browsing, rubbing and gnawing until they reach about 13 cm diameter and have grown out of the browse zone.

  9. Mercury in Red Aspen Boletes (Leccinum aurantiacum) mushrooms and the soils.

    Science.gov (United States)

    Falandysz, Jerzy; Kowalewska, Izabela; Nnorom, Innocent C; Drewnowska, Małgorzata; Jarzyńska, Grażyna

    2012-01-01

    This communication reports data on the mercury contents of Red Aspen Boletes (Leccinum aurantiacum) mushrooms and the forest soils substrate layer (0-10 cm) underneath the fruit bodies collected from nine spatially distant sites across Poland. Total Hg concentration in soil substrate in seven of the nine sites studied varied from 0.0078 ± 0.0012 to 0.028 ± 0.007 μg/g dry weight (dw) and this could be considered baseline concentrations for uncontaminated forest soils in Poland. The arithmetic mean of mercury in Red Aspen Bolete caps varied, depending on the site from 0.27 ± 0.07 to 1.3 ± 0.6 μg/g dw. The lowest Hg contents in soil (0.011 ± 0.006 μg/g and 0.009 ± 0.002 μg/g) were observed for the sites of Wandalin and Opole Lubelskie (from Lubelska Upland region) with the corresponding highest bioconcentration factor (BCF) values of 130 ± 66 and 110 ± 13 for the mushroom caps and 58 ± 29 and 64 ± 8 for the stipes, respectively. The BCF values in caps showed a downward trend with increasing mercury content of soil. A meal of 300 g of fresh caps of Red Aspen Bolete from Aleksandrów Kujawski region could expose a consumer to 8.1 μg Hg, while this will be 39 μg at the Lubelska Upland amounting to 39 and 186 % of daily Hg reference dose, respectively.

  10. Spatial and temporal variability of xylan distribution in differentiating secondary xylem of hybrid aspen.

    Science.gov (United States)

    Kim, Jong Sik; Sandquist, David; Sundberg, Björn; Daniel, Geoffrey

    2012-06-01

    Xylans occupy approximately one-third of the cell wall components in hardwoods and their chemical structures are well understood. However, the microdistribution of xylans (O-acetyl-4-O-methylglucuronoxylans, AcGXs) in the cell wall and their correlation with functional properties of cells in hardwood xylem is poorly understood. We demonstrate here the spatial and temporal distribution of xylans in secondary xylem cells of hybrid aspen using immunolocalization with LM10 and LM11 antibodies. Xylan labeling was detected earliest in fibers at the cell corner of the S₁ layer, and then later in vessels and ray cells respectively. Fibers showed a heterogeneous labeling pattern in the mature cell wall with stronger labeling of low substituted xylans (lsAcGXs) in the outer than inner cell wall. In contrast, vessels showed uniform labeling in the mature cell wall with stronger labeling of lsAcGXs than fibers. Xylan labeling in ray cells was detected much later than that in fibers and vessels, but was also detected at the beginning of secondary cell wall formation as in fibers and vessels with uniform labeling in the cell wall regardless of developmental stage. Interestingly, pit membranes including fiber-, vessel- and ray-vessel pits showed strong labeling of highly substituted xylans (hsAcGXs) during differentiation, although this labeling gradually disappeared during pit maturation. Together our observations indicate that there are temporal and spatial variations of xylan deposition and chemical structure of xylans between cells in aspen xylem. Differences in xylan localization between aspen (hardwood) and cedar (softwood) are also discussed.

  11. A simulation study of Solid Oxide fuel cell for IGCC power generation using Aspen Plus

    DEFF Research Database (Denmark)

    Rudra, Souman; Kim, Hyung Taek

    2010-01-01

    in a more accurate fuel cell model giving an advantage over previous system studies based on simplified SOFC models. The objective of this work is to develop a simulation model of a SOFC for IGFC system, flexible enough for use in future development, capable of predicting system performance under various...... operating conditions and using diverse fuels. The SOFC stack model developed using the chemical process flow sheet simulator Aspen Plus which is of equilibrium type and is based on Gibbs free energy minimization. The SOFC model performs heat and mass balances and considers the ohmic, activation...

  12. 甲醇合成过程的Aspen模拟%Aspen Analog of Methanol Synthesis Process

    Institute of Scientific and Technical Information of China (English)

    孟庆军

    2005-01-01

    通过Aspen-Plus工具,采用合成动力学方程对甲醇合成流程进行了全流程模拟,分析了模拟计算结果.从循环气量、合成压力、冷却水温、合成塔进口温度、合成塔结构、催化剂装填量等方面论述了操作条件和反应器尺寸的变化对合成回路的影响.

  13. Nanocrystalline cellulose from aspen kraft pulp and its application in deinked pulp.

    Science.gov (United States)

    Xu, Qinghua; Gao, Yang; Qin, Menghua; Wu, Kaili; Fu, Yingjuan; Zhao, Jian

    2013-09-01

    Nanocrystalline cellulose (NCC) isolated from bleached aspen kraft pulp was characterized, and its application as pulp strengthening additive and retention aid was investigated. Results showed that NCC with high crystallinity of more than 80% can be obtained using 64 wt% sulfuric acid. The structure of nanocrystalline cellulose is parallelepiped rod-like, and their cross-sectional dimension is in the nanometer range with a high aspect ratio. The formation of microparticle retention systems during the application of NCC together with cationic polyacrylamide and cationic starch in deinked pulp was able to further improve pulp retention and strength properties without negative influence on the drainage.

  14. 关于Aspen Plus在化工设计中应用的探讨

    Institute of Scientific and Technical Information of China (English)

    耿晓云[1; 李彦菊[2

    2015-01-01

    在化工设计中,Aspen Plus 是针对化工为代表的功能强大的过程系统模拟软件。介绍了如何将其引入化工设计环节。使用软件模拟可以节省计算量、提高效率,培养设计工作者解决工程问题的能力,与手工计算的差异对比分析原因。

  15. ASPEN PLUS与化工专业核心课程体系建设

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      通过分析化工专业课程体系,在传统教学的基础上,探讨将 Aspen Plus 流程模拟软件有目的、有步骤地引入化工专业核心课程化工原理、化学反应工程、化工热力学和分离工程的教学中,强化化工专业核心课程体系的建设。

  16. 关于Aspen Plus在化工设计中应用的探讨

    Institute of Scientific and Technical Information of China (English)

    耿晓云; 李彦菊

    2015-01-01

    在化工设计中,Aspen Plus 是针对化工为代表的功能强大的过程系统模拟软件,本文介绍了如何将其引入化工设计环节。使用软件模拟可以节省计算量、提高效率,培养设计工作者解决工程问题的能力,与手工计算的差异对比分析原因。

  17. 偏氟乙烯精馏的Aspen Plus模拟分析

    Institute of Scientific and Technical Information of China (English)

    钟益堂

    2014-01-01

    通过Aspen Plus模拟软件对偏氟乙烯精馏过程进行了模拟.对精馏塔的进料位置、回流比、馏出比进行了灵敏度分析,综合考虑得出精馏塔适宜进料位置NF、回流摩尔比R、馏出摩尔比D/F分别是32、0.12、0.89.模拟结果与实际生产值基本一致,可指导工业生产.

  18. ASPEN PLUS优化甲醇水分离塔操作

    Institute of Scientific and Technical Information of China (English)

    姬加良

    2010-01-01

    应用ASPEN PLUS工程软件对低温甲醇洗装置的甲醇水分离塔进行模拟,并与设计工艺包进行对比。对塔顶回流甲醇在不同含水量下的工况进行优化,将优化数据与该塔实际运行结果进行比较,为生产操作提供数据指导。

  19. Laser Capture Microdissection Protocol for Xylem Tissues of Woody Plants

    Science.gov (United States)

    Blokhina, Olga; Valerio, Concetta; Sokołowska, Katarzyna; Zhao, Lei; Kärkönen, Anna; Niittylä, Totte; Fagerstedt, Kurt

    2017-01-01

    Laser capture microdissection (LCM) enables precise dissection and collection of individual cell types from complex tissues. When applied to plant cells, and especially to woody tissues, LCM requires extensive optimization to overcome such factors as rigid cell walls, large central vacuoles, intercellular spaces, and technical issues with thickness and flatness of the sections. Here we present an optimized protocol for the laser-assisted microdissection of developing xylem from mature trees: a gymnosperm (Norway spruce, Picea abies) and an angiosperm (aspen, Populus tremula) tree. Different cell types of spruce and aspen wood (i.e., ray cells, tracheary elements, and fibers) were successfully microdissected from tangential, cross and radial cryosections of the current year’s growth ring. Two approaches were applied to achieve satisfactory flatness and anatomical integrity of the spruce and aspen specimens. The commonly used membrane slides were ineffective as a mounting surface for the wood cryosections. Instead, in the present protocol we use glass slides, and introduce a glass slide sandwich assembly for the preparation of aspen sections. To ascertain that not only the anatomical integrity of the plant tissue, but also the molecular features were not compromised during the whole LCM procedure, good quality total RNA could be extracted from the microdissected cells. This showed the efficiency of the protocol and established that our methodology can be integrated in transcriptome analyses to elucidate cell-specific molecular events regulating wood formation in trees. PMID:28101088

  20. 采用Aspen Plus设计计算蒸汽减温减压系统

    Institute of Scientific and Technical Information of China (English)

    王潇; 刘明; 夏红勋

    2015-01-01

    采用Aspen Plus设计计算蒸汽减温减压系统,并将所得数据与现场实际装置的运行情况相比较。结果表明,采用Aspen Plus模拟计算的结果与生产装置的运行参数和物性手册的数据相一致,在工程允许误差范围之内。

  1. The response of Populus spp. to cadmium stress: chemical, morphological and proteomics study.

    Science.gov (United States)

    Marmiroli, Marta; Imperiale, Davide; Maestri, Elena; Marmiroli, Nelson

    2013-10-01

    Poplar (Populus) species are seen as candidates for removing heavy metal contamination from polluted soil. A bottom-up multidisciplinary approach was utilized to compare the performances of clones 58-861 and Poli (Populus nigra) and A4A, a Populus nigra × Populus deltoides hybrid to Cd toxicity. Qualitative and quantitative differences in their tolerance to Cd exposure and the uptake, accumulation and translocation of Cd were noted following the hydroponic exposure of rooted cuttings to 20 μM CdSO₄ for either 48 h or 14 d. Cadmium was less toxic for the hybrid clone A4A as compared to Poli and 58-861. Cd uptake and root to shoot translocation were determined by AAS, and its compartmentation was analyzed using SEM/EDX. A comparative proteomic approach was utilized to identify changes in proteins expression according to dose and time of exposure. Toxicity to Cd mainly influenced proteins related to general defense, stress response and carbohydrate metabolism.

  2. Genome-wide analysis of the structural genes regulating defense phenylpropanoid metabolism in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Tschaplinski, Timothy J [ORNL; Tsai, Chung-Jui [Michigan Technological University; Harding, Scott A [Michigan Technological University; Lindroth, richard L [University of Wisconsin, Madison; Yuan, Yinan [Michigan Technological University

    2006-01-01

    Salicin-based phenolic glycosides, hydroxycinnamate derivatives and flavonoid-derived condensed tannins comprise up to one-third of Populus leaf dry mass. Genes regulating the abundance and chemical diversity of these substances have not been comprehensively analysed in tree species exhibiting this metabolically demanding level of phenolic metabolism. Here, shikimate-phenylpropanoid pathway genes thought to give rise to these phenolic products were annotated from the Populus genome, their expression assessed by semiquantitative or quantitative reverse transcription polymerase chain reaction (PCR), and metabolic evidence for function presented. Unlike Arabidopsis, Populus leaves accumulate an array of hydroxycinnamoyl-quinate esters, which is consistent with broadened function of the expanded hydroxycinnamoyl-CoA transferase gene family. Greater flavonoid pathway diversity is also represented, and flavonoid gene families are larger. Consistent with expanded pathway function, most of these genes were upregulated during wound-stimulated condensed tannin synthesis in leaves. The suite of Populus genes regulating phenylpropanoid product accumulation should have important application in managing phenolic carbon pools in relation to climate change and global carbon cycling.

  3. RepPop: a database for repetitive elements in Populus trichocarpa

    Directory of Open Access Journals (Sweden)

    Xu Ying

    2009-01-01

    Full Text Available Abstract Background Populus trichocarpa is the first tree genome to be completed, and its whole genome is currently being assembled. No functional annotation about the repetitive elements in the Populus trichocarpa genome is currently available. Results We predicted 9,623 repetitive elements in the Populus trichocarpa genome, and assigned functions to 3,075 of them (31.95%. The 9,623 repetitive elements cover ~40% of the current (partially assembled genome. Among the 9,623 repetitive elements, 668 have copies only in the contigs that have not been assigned to one of the 19 chromosome while the rest all have copies in the partially assembled chromosomes. Conclusion All the predicted data are organized into an easy-to-use web-browsable database, RepPop. Various search capabilities are provided against the RepPop database. A Wiki system has been set up to facilitate functional annotation and curation of the repetitive elements by a community rather than just the database developer. The database RepPop will facilitate the assembling and functional characterization of the Populus trichocarpa genome.

  4. Litter Quality of Populus Species as Affected by Free-Air CO2

    NARCIS (Netherlands)

    Vermue, E.; Buurman, P.; Hoosbeek, M.R.

    2009-01-01

    The effect of elevated CO2 and nitrogen fertilization on the molecular chemistry of litter of three Populus species and associated soil organic matter (SOM) was investigated by pyrolysis-gas chromatography/mass spectrometry. The results are based on 147 quantified organic compounds in 24 litter samp

  5. Identification of quantitative trait loci and candidate genes for cadmium tolerance in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Induri, Brahma R [West Virginia University; Ellis, Danielle R [West Virginia University; Slavov, Goncho T. [West Virginia University; Yin, Tongming [ORNL; Zhang, Xinye [ORNL; Tuskan, Gerald A [ORNL; DiFazio, Steven P [West Virginia University

    2012-01-01

    Understanding genetic variation for the response of Populus to heavy metals like cadmium (Cd) is an important step in elucidating the underlying mechanisms of tolerance. In this study, a pseudo-backcross pedigree of Populus trichocarpa Torr. & Gray and Populus deltoides Bart. was characterized for growth and performance traits after Cd exposure. A total of 16 quantitative trait loci (QTL) at logarithm of odds (LOD) ratio 2.5 were detected for total dry weight, its components and root volume. Major QTL for Cd responses were mapped to two different linkage groups and the relative allelic effects were in opposing directions on the two chromosomes, suggesting differential mechanisms at these two loci. The phenotypic variance explained by Cd QTL ranged from 5.9 to 11.6% and averaged 8.2% across all QTL. A whole-genome microarray study led to the identification of nine Cd-responsive genes from these QTL. Promising candidates for Cd tolerance include an NHL repeat membrane-spanning protein, a metal transporter and a putative transcription factor. Additional candidates in the QTL intervals include a putative homolog of a glutamate cysteine ligase, and a glutathione-S-transferase. Functional characterization of these candidate genes should enhance our understanding of Cd metabolism and transport and phytoremediation capabilities of Populus.

  6. ADVANCE IN RESEARCH ON DROUGHT RESISTANCE OF POPULUS%杨树抗旱性研究进展

    Institute of Scientific and Technical Information of China (English)

    尹春英; 李春阳

    2003-01-01

    The drought resistance of woody plants, in particular, Populus, was reviewed in this paper. Studies about drought resistance of Populus mostly focused on changes in growth properties, physiological adaptation and biochemical aspects, but a few on molecular biology. The indexes of drought adaptation and productivity were analyzed and these indexes could be employed to identify drought resistance of woody plants. Combination of such different approaches will, hopefully, give us a more complete understanding of the various regulatory mechanisms in trees than what we may have today. With development of the molecular biology of woody plants, the sluties on stress resistance of Populus which was regarded as a model plant, are summarised. Ref 96

  7. Geographic Patterns and Stand Variables Influencing Growth and Vigor of Populus tremuloides in the Sierra Nevada (USA)

    OpenAIRE

    2012-01-01

    Awareness of geographic patterns and stand variables that influence tree growth will help forest managers plan appropriate management and monitoring strategies. We quantified influences of stand location, species composition, stand density, and tree size on aspen tree growth and vigor around the Lake Tahoe Basin in the Sierra Nevada Mountains of California and Nevada, USA. Radial growth data were taken from increment cores. Aspen trees on the south and west sides of the lake grew 20–25% faste...

  8. Aldehyde Dehydrogenase Gene Superfamily in Populus: Organization and Expression Divergence between Paralogous Gene Pairs.

    Directory of Open Access Journals (Sweden)

    Feng-Xia Tian

    Full Text Available Aldehyde dehydrogenases (ALDHs constitute a superfamily of NAD(P+-dependent enzymes that catalyze the irreversible oxidation of a wide range of reactive aldehydes to their corresponding nontoxic carboxylic acids. ALDHs have been studied in many organisms from bacteria to mammals; however, no systematic analyses incorporating genome organization, gene structure, expression profiles, and cis-acting elements have been conducted in the model tree species Populus trichocarpa thus far. In this study, a comprehensive analysis of the Populus ALDH gene superfamily was performed. A total of 26 Populus ALDH genes were found to be distributed across 12 chromosomes. Genomic organization analysis indicated that purifying selection may have played a pivotal role in the retention and maintenance of PtALDH gene families. The exon-intron organizations of PtALDHs were highly conserved within the same family, suggesting that the members of the same family also may have conserved functionalities. Microarray data and qRT-PCR analysis indicated that most PtALDHs had distinct tissue-specific expression patterns. The specificity of cis-acting elements in the promoter regions of the PtALDHs and the divergence of expression patterns between nine paralogous PtALDH gene pairs suggested that gene duplications may have freed the duplicate genes from the functional constraints. The expression levels of some ALDHs were up- or down-regulated by various abiotic stresses, implying that the products of these genes may be involved in the adaptation of Populus to abiotic stresses. Overall, the data obtained from our investigation contribute to a better understanding of the complexity of the Populus ALDH gene superfamily and provide insights into the function and evolution of ALDH gene families in vascular plants.

  9. Identification of Quantitative Trait Loci (QTL) and Candidate Genes for Cadmium Tolerance in Populus

    Energy Technology Data Exchange (ETDEWEB)

    Induri, Brahma R [West Virginia University; Ellis, Danielle R [West Virginia University; Slavov, Gancho [West Virginia University; Yin, Tongming [ORNL; Muchero, Wellington [ORNL; Tuskan, Gerald A [ORNL; DiFazio, Stephen P [West Virginia University

    2012-01-01

    Knowledge of genetic variation in response of Populus to heavy metals like cadmium (Cd) is an important step in understanding the underlying mechanisms of tolerance. In this study, a pseudo-backcross pedigree of Populus trichocarpa and Populus deltoides was characterized for Cd exposure. The pedigree showed significant variation for Cd tolerance thus enabling the identification of relatively tolerant and susceptible genotypes for intensive characterization. A total of 16 QTLs at logarithm of odds (LOD) ratio > 2.5, were found to be associated with total dry weight, its components, and root volume. Four major QTLs for total dry weight were mapped to different linkage groups in control (LG III) and Cd conditions (LG XVI) and had opposite allelic effects on Cd tolerance, suggesting that these genomic regions were differentially controlled. The phenotypic variation explained by Cd QTL for all traits under study varied from 5.9% to 11.6% and averaged 8.2% across all QTL. Leaf Cd contents also showed significant variation suggesting the phytoextraction potential of Populus genotypes, though heritability of this trait was low (0.22). A whole-genome microarray study was conducted by using two genotypes with extreme responses for Cd tolerance in the above study and differentially expressed genes were identified. Candidate genes including CAD2 (CADMIUM SENSITIVE 2), HMA5 (HEAVY METAL ATPase5), ATGTST1 (Arabidopsis thaliana Glutathione S-Transferase1), ATGPX6 (Glutathione peroxidase 6), and ATMRP 14 (Arabidopsis thaliana Multidrug Resistance associated Protein 14) were identified from QTL intervals and microarray study. Functional characterization of these candidate genes could enhance phytoremediation capabilities of Populus.

  10. Growth Characteristics of Four Clone of Populus alba × Populus bolleana%4个银×新杨无性系生长特性

    Institute of Scientific and Technical Information of China (English)

    王宝庆; 李丕军; 李宏; 李素琼; 雷双喜

    2011-01-01

    Growth characteristics of Populus alba X Populus bolleana plantaion in Plain Forestry Farm of Hi Area had been studied. The results showed than tree height growth of four clone of Populus alba X Populus bolleana was earlier than the breast diameter growth. There were significant differences among single plants in the middle and later periods of plant growth. The maximum of current annual increment and average annual increment of tree height appeared nearly synchronously,so did the breast diameter. The current annual increment of the tree height and the average annual increment intersected with each other nearly in 4th-6th year. The current annual increment of breast diameter and the average annual increment intersected about in 6th-7th year. But the maximum of current annual increment of timber volume appeared much more earlier than the maximum of mean annual increment;From the view of growth process of four clone of Populus alba Xpopulus bolleana produced 18 years ago,the growth can be divided into three periods;0 - 6 years were the young treelet period,during which the tree height and breast diameter grew faster;7 - 14 years were the high-growing period, during which the tree height and breast diameter grew at high speed. 15 - 18 years were the near mature period. The average current increment of Populus alba X Populus bolleana and current annual increment intersected with each other about in 16 years with quantitative mature, in this moment,the rotation of humbering can be operated.%对伊犁地区筛选的4个银×新杨无性系生长特性进行研究.结果表明,银×新杨4个无性系的高生长要早于胸径生长,生长中后期单株之间差异明显;树高连年生长量最大值与平均生长量最大值几乎同步出现,胸径亦如此,树高连年生长量在第4~6年时与平均生长量相交,胸径连年生长量和平均生长量在第6~7年时相交.从18a生的4个无性系生长过程来看,生长可分为3个时期:第0~6

  11. Severe obesity: a growing health concern A.S.P.E.N. should not ignore.

    Science.gov (United States)

    Shikora, Scott A

    2005-01-01

    The definition of malnutrition in the published standards of the American Society of Parenteral and Enteral Nutrition (A.S.P.E.N.) is any derangement in the normal nutrition status and includes overnutrition, commonly referred to as obesity. The incidence of obesity is increasing and reaching epidemic proportions in the United States and even worldwide. This has significant financial impact as our society spends billions of dollars on fad diets, commercial weight-loss programs, nutrition and dietary supplements, prescription and over-the-counter medications, and health clubs. Another approximately dollars 100 billion are spent to treat the medical consequences of obesity. Currently, for those patients with intractable morbid obesity, defined as having a body mass index >40 kg/m2, surgery offers the only option for achieving meaningful and sustainable weight loss. The resultant weight loss dramatically improves health and decreases the cost of health care for these patients. Years of refinement in technology and the introduction of safer and less invasive procedures have dramatically reduced the short-term morbidities and long-term metabolic consequences of these procedures. This address will review the field of weight loss (bariatric) surgery and will offer a compelling request for A.S.P.E.N. to include obesity in its fabric.

  12. Process simulation and maximization of energy output in chemical-looping combustion using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Xiao Zhang, Subhodeep Banerjee, Ling Zhou, Ramesh Agarwal

    2015-01-01

    Full Text Available Chemical-looping combustion (CLC is currently considered as a leading technology for reducing the economic cost of CO2 capture. In this paper, several process simulations of chemical-looping combustion are conducted using the ASPEN Plus software. The entire CLC process from the beginning of coal gasification to the reduction and oxidation of the oxygen carrier is modeled and validated against experimental data. The energy balance of each major component of the CLC process, e.g., the fuel and air reactors and air/flue gas heat exchangers is examined. Different air flow rates and oxygen carrier feeding rates are used in the simulations to obtain the optimum ratio of coal, air, and oxygen carrier that produces the maximum power. Two scaled-up simulations are also conducted to investigate the influence of increase in coal feeding on power generation. It is demonstrated that the optimum ratio of coal, air supply, and oxygen carrier for maximum power generation remains valid for scaled-up cases with substantially larger coal feeding rates; the maximum power generation scales up linearly by using the process simulation models in ASPEN Plus. The energy output from four different types of coals is compared, and the optimum ratio of coal, air supply and oxygen carrier for maximum power generation for each type of coal is determined.

  13. Aspen Plus在换热器工艺选型物性计算中的应用%Application of Plus Aspen in Physical Property Calculation for Technique Lectotype of Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    姚立影; 常春梅; 唐海; 姚炜屹

    2016-01-01

    The thermal physical properties of the saturated moist air, the flue gas and the mixed feeding of the hydrogen heat exchanger are calculated by applying the Plus Aspen software, including the density, viscosity, thermal conductibity coefficient, specific heat capacity and etc. Then the results are compared with the reported values or the measured values. It shows that the deviation between the calculated values from the Plus Aspen and the reported values is less than 13%which meets the engineering requirements so that it's of great preference for the design of the heat exchanger.%应用Aspen Plus 软件对饱和湿空气、烟气及加氢换热器混合进料的热物性进行计算,包括换热器设计所涉及的密度、黏度、导热系数、比热容等物性参数,并将计算结果与文献值或实测值进行比较。结果表明,基于Aspen Plus的计算结果与文献值最大偏差不超过13%,满足工程要求,可以为换热器设计提供参考依据。

  14. 基于Aspen Plus物性分析计算甲醇水溶液凝固点%Calculation for freezing points of methanol aqueous solution based on property analysis of Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    刘光明; 王伟鹏

    2013-01-01

    探讨了气液固多相平衡的机理,利用活度系数法计算各相热力学性质,采用Aspen plus物性分析计算不同浓度的甲醇水溶液凝固点,将计算结果与手册值进行比较,结果表明:模拟计算结果与手册值较为接近,在工程误差允许的范围内,可以用Aspen plus物性分析计算甲醇水溶液凝固点.%The multiphase balance mechanism of gas,liquid and solid was discussed.The thermodynamic properties of which were calculated by activity coefficient method.The freezing points of the methanol aqueous solution with different concentrations were calculated using the properties analysis of Aspen Plus.The results show that the simulation result is much close to the manual value.Within the allowed range of engineering error,the freezing points of the methanol aqueous solution can be simulated based on properties analysis of Aspen Plus and used in the practical engineering.

  15. Application of Aspen Plus in the Practical Teaching of Chemical Technology%基于 Aspen Plus 在化工工艺学教学中的应用

    Institute of Scientific and Technical Information of China (English)

    唐新宜

    2016-01-01

    化工工艺学是一门理论与生产相结合的课程。本文讨论了化工流程模拟软件Aspen与化工工艺学教学的关系,将Aspen Plus流程模拟软件逐步引入到化工工艺学实践教学中,加深了学生对化工生产工艺的理解,并提高了学生利用工具解决实际问题的能力。引入Aspen Plus软件作为化工工艺学教学辅助工具,能使教学更接近实际生产过程,拓宽了学生的视野。%Chemical Technology is a rather practical course .The relationship between Aspen Plus software and Chemical Technology were discussed .Aspen Plus software was introduced in the teaching of Chemical Technology course to strengthen the understanding of Chemical Engineering courses and improve the hands-on and implementing ability of the students , which made the teaching closer to engineering practice and broaden the students ’visual field.

  16. The Rise of Netpolitik: How the Internet Is Changing International Politics and Diplomacy. A Report of the Annual Aspen Institute Roundtable on Information Technology (11th, Aspen, Colorado, August 1-4, 2002).

    Science.gov (United States)

    Bollier, David

    This document is an interpretive synthesis of the discussion at a conference sponsored by the Aspen Institute that sought to develop new ways to understand how the Internet is changing the powers of the nation-state, the conduct of international relations, and the definitions of nation security. This report examines how the Internet and other…

  17. Analysis of CO2 Separation by Selexol Based on Aspen Plus%基于Aspen Plus对Selexol分离CO2流程的分析

    Institute of Scientific and Technical Information of China (English)

    邱朋华; 李丹丹; 徐宝龙; 呼姚; 杜昌帅; 吴少华

    2014-01-01

    整体煤气化联合循环发电系统可采取燃烧前捕集CO2的方法,处理的合成气量少,能耗低,且能够实现 CO2的近零排放,在 CO2脱除方面具有很大的优势。文中基于Aspen Plus 对 CO2/H2S 联合脱除和分别脱除流程建立了模型,对2流程的能耗、CO2及H2S的脱除效率以及Selexol溶液的再生性能进行了分析。得出:在出口 CO2纯度相同的情况下,CO2/H2S联合脱除流程的能耗仅占CO2/H2S分别脱除的21%左右,CO2脱除效率高于分别脱除流程,2流程Selexol溶液的再生性能相差不大,且H2S脱除效率也可达到95%以上,因此CO2/H2S联合脱除流程更经济。%Integrated gasification combined cycle (IGCC)power generation system can adopt pre-combustion CO2 capture methods, handling with less syngas and have low energy consumption, which can achieve near-zero emissions of CO2, resulting in great advantages in terms of CO2 removal. Based on Aspen Plus, combined removal of CO2/H2S (CRCH) and separate removal of CO2/H2S (SRCH) were modeled . Energy consumption, capture efficiency of CO2 and H2S, as well as the regeneration performance of Selexol were analyzed by the two models. The results indicate that:while keeping the same CO2 purity in outlet stream, the energy consumption of CRCH accounts for only 21% of SRCH; the CO2 capture efficiency is higher than that of SRCH, the regeneration performance of Selexol is almost the same for the two processes, and the capture efficiency of H2S in the two processes can be higher than 95%. All those prove that CRCH is more economic than SRCH.

  18. 77 FR 31351 - Adequacy Determination for Aspen PM10 and Fort Collins Carbon Monoxide Maintenance Plans' Motor...

    Science.gov (United States)

    2012-05-25

    ... 93.118(e)(4), which was promulgated August 15, 1997 (62 FR 43780). We described our process for... (69 FR 40004). In addition, in certain areas with monitored ambient carbon monoxide (CO) values... AGENCY Adequacy Determination for Aspen PM and Fort Collins Carbon Monoxide Maintenance Plans'...

  19. Genome-wide association implicates numerous genes and pleiotropy underlying ecological trait variation in natural populations of Populus trichocarpa

    Energy Technology Data Exchange (ETDEWEB)

    McKown, Athena [University of British Columbia, Vancouver; Klapste, Jaroslav [University of British Columbia, Vancouver; Guy, Robert [University of British Columbia, Vancouver; Geraldes, Armando [University of British Columbia, Vancouver; Porth, Ilga [University of British Columbia, Vancouver; Hannemann, Jan [University of Victoria, Canada; Friedmann, Michael [University of British Columbia, Vancouver; Muchero, Wellington [ORNL; Tuskan, Gerald A [ORNL; Ehlting, Juergen [University of Victoria, Canada; Cronk, Quentin [University of British Columbia, Vancouver; El-Kassaby, Yousry [University of British Columbia, Vancouver; Mansfield, Shawn [University of British Columbia, Vancouver; Douglas, Carl [University of British Columbia, Vancouver

    2014-01-01

    To uncover the genetic basis of phenotypic trait variation, we used 448 unrelated wild accessions of black cottonwood (Populus trichocarpa Torr. & Gray) from natural populations throughout western North America. Extensive information from large-scale trait phenotyping (with spatial and temporal replications within a common garden) and genotyping (with a 34K Populus SNP array) of all accessions were used for gene discovery in a genome-wide association study (GWAS).

  20. 基于Aspen Plus的自复叠热泵模拟%The Simulation of Auto-Cascade Heat Pump Ssystem Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    刘金平; 朱海明; 刘雪峰

    2010-01-01

    自复叠热泵的变工况运行对其性能影响很大.应用Aspen Plus软件,对冷凝器入口水温从40~55℃的4个工况下的自复叠热泵进行了流程模拟,并对流程中各点参数变化进行了分析,对节流阀的流态进行了计算分析.结果表明,自复叠热泵在两个节流阀开度不变时,随着冷凝器入口水温的升高,压缩机耗功增加,主流与支流流量增大,蒸发压力升高,压缩机入口比容减小,循环的质量流量增大;两个节流阀均未达到雍塞流.

  1. Pulverized Coal Gasification Simulation Based on Aspen Plus Software%基于Aspen Plus的粉煤气化模拟

    Institute of Scientific and Technical Information of China (English)

    张宗飞; 汤连英; 吕庆元; 章卫星; 何正兆; 毕东煌

    2008-01-01

    Aspen Plus为模拟工具,选择反应平衡模型,并应用Gibbs自由能最小化方法建立了Shell粉煤气化模型;通过对神华、沾化和天碱煤种的气化模拟,对建立的模型进行了检验,结果表明:用N2输送粉煤的气化过程能够很好地模拟,而用CO2输送粉煤的气化过程模拟偏差较大.以沾化煤种为例,检验了气化炉散热损失取煤总热值约2%的合理性;研究了不同操作条件下的气化性能,结果表明:提高温度和压力可使气化过程得到强化.

  2. Response Surface Methodology and Aspen Plus Integration for the Simulation of the Catalytic Steam Reforming of Ethanol

    Directory of Open Access Journals (Sweden)

    Bernay Cifuentes

    2017-01-01

    Full Text Available The steam reforming of ethanol (SRE on a bimetallic RhPt/CeO2 catalyst was evaluated by the integration of Response Surface Methodology (RSM and Aspen Plus (version 9.0, Aspen Tech, Burlington, MA, USA, 2016. First, the effect of the Rh–Pt weight ratio (1:0, 3:1, 1:1, 1:3, and 0:1 on the performance of SRE on RhPt/CeO2 was assessed between 400 to 700 °C with a stoichiometric steam/ethanol molar ratio of 3. RSM enabled modeling of the system and identification of a maximum of 4.2 mol H2/mol EtOH (700 °C with the Rh0.4Pt0.4/CeO2 catalyst. The mathematical models were integrated into Aspen Plus through Excel in order to simulate a process involving SRE, H2 purification, and electricity production in a fuel cell (FC. An energy sensitivity analysis of the process was performed in Aspen Plus, and the information obtained was used to generate new response surfaces. The response surfaces demonstrated that an increase in H2 production requires more energy consumption in the steam reforming of ethanol. However, increasing H2 production rebounds in more energy production in the fuel cell, which increases the overall efficiency of the system. The minimum H2 yield needed to make the system energetically sustainable was identified as 1.2 mol H2/mol EtOH. According to the results of the integration of RSM models into Aspen Plus, the system using Rh0.4Pt0.4/CeO2 can produce a maximum net energy of 742 kJ/mol H2, of which 40% could be converted into electricity in the FC (297 kJ/mol H2 produced. The remaining energy can be recovered as heat.

  3. Genome resequencing in Populus: Revealing large-scale genome variation and implications on specialized-trait genomics

    Energy Technology Data Exchange (ETDEWEB)

    Muchero, Wellington [ORNL; Labbe, Jessy L [ORNL; Priya, Ranjan [University of Tennessee, Knoxville (UTK); DiFazio, Steven P [West Virginia University, Morgantown; Tuskan, Gerald A [ORNL

    2014-01-01

    To date, Populus ranks among a few plant species with a complete genome sequence and other highly developed genomic resources. With the first genome sequence among all tree species, Populus has been adopted as a suitable model organism for genomic studies in trees. However, far from being just a model species, Populus is a key renewable economic resource that plays a significant role in providing raw materials for the biofuel and pulp and paper industries. Therefore, aside from leading frontiers of basic tree molecular biology and ecological research, Populus leads frontiers in addressing global economic challenges related to fuel and fiber production. The latter fact suggests that research aimed at improving quality and quantity of Populus as a raw material will likely drive the pursuit of more targeted and deeper research in order to unlock the economic potential tied in molecular biology processes that drive this tree species. Advances in genome sequence-driven technologies, such as resequencing individual genotypes, which in turn facilitates large scale SNP discovery and identification of large scale polymorphisms are key determinants of future success in these initiatives. In this treatise we discuss implications of genome sequence-enable technologies on Populus genomic and genetic studies of complex and specialized-traits.

  4. Short communication. A review on the efficacy tests and risk analyses conducted on Chondrostereum purpureum, a potential biocontrol agent, in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Hantula, J.; Hamberg, L.; Vartiamaki, H.; Korhonen, K.; Uotila, A.

    2012-11-01

    Hardwood sprouting is a problem in forest regeneration areas, under electric lines, on roadsides and railways. In Finland, isolates of Chondrostereum purpureum were screened by field experiments for their efficiency to control sprouting. The proportion of dead stumps with the best isolates exceeded 80% on birch (Betula pendula and B. pubescens), and C. purpureum was also found to affect the sprouting of aspen (Populus tremula) and rowan (Sorbus aucuparia). The risks of C. purpureum based biocontrol were evaluated by population genetic analysis. It showed that C. purpureum is a geographically undifferentiated species that does not reproduce clonally. The risk of infection of non-target trees was found to be highest in early spring. These findings suggest that the risks of using C. purpureum in biocontrol are small. (Author) 36 refs.

  5. Tree and shrub expansion over the past 34 years at the tree-line near Abisko, Sweden.

    Science.gov (United States)

    Rundqvist, Sara; Hedenås, Henrik; Sandström, Anneli; Emanuelsson, Urban; Eriksson, Håkan; Jonasson, Christer; Callaghan, Terry V

    2011-09-01

    Shrubs and trees are expected to expand in the sub-Arctic due to global warming. Our study was conducted in Abisko, sub-arctic Sweden. We recorded the change in coverage of shrub and tree species over a 32- to 34-year period, in three 50 x 50 m plots; in the alpine-tree-line ecotone. The cover of shrubs and trees (tree stems (> or =3.5 cm) were noted and positions determined. There has been a substantial increase of cover of shrubs and trees, particularly dwarf birch (Betula nana), and mountain birch (Betula pubescens ssp. czerepanovii), and an establishment of aspen (Populus tremula). The other species willows (Salix spp.), juniper (Juniperus communis), and rowan (Sorbus aucuparia) revealed inconsistent changes among the plots. Although this study was unable to identify the causes for the change in shrubs and small trees, they are consistent with anticipated changes due to climate change and reduced herbivory.

  6. Evolution and environmental degradation of superhydrophobic aspen and black locust leaf surfaces

    Science.gov (United States)

    Tranquada, George Christopher

    The current study is focused on the characterization of four natural leaf species (quaking, bigtooth and columnar european aspen as well as black locust) possessing a unique dual-scale cuticle structure composed of micro- and nano-scale asperities, which are able to effectively resist wetting (superhydrophobic), characteristic of The Lotus Effect. Scanning Electron Microscopy (SEM) was used to track the growth and evolution of their distinctive nano-scale epicuticular wax (ECW) morphologies over one full growing season. In addition, the stability of their superhydrophobic property was tested in various environments. It was determined that the long-term stability of these surfaces is tentatively linked to various environmental stress factors. Specifically, a combination of high temperature and humidity caused the degradation of nanoscale asperities and loss of the superhydrophobic property. The dual-scale surface structure was found to provide a suitable template for the design of future superhydrophobic engineering materials.

  7. Simulation and validation of chemical-looping combustion using ASPEN plus

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Ling [Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang 212013 (China); Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130 (United States); Zhang, Zheming; Agarwal, Ramesh K. [Department of Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130 (United States)

    2013-07-01

    Laboratory-scale experimental studies have demonstrated that Chemical-Looping Combustion (CLC) is an advanced technology which holds great potential for high-efficiency low-cost carbon capture. The generated syngas in CLC is subsequently oxidized to CO2 and H2O by reaction with an oxygen carrier. In this paper, process-level models of CLC are established in ASPEN Plus code for detailed simulations. The entire CLC process, from the beginning of coal gasification to reduction and oxidation of the oxygen carrier is modeled. The heat content of each major component such as fuel and air reactors and air/flue gas heat exchangers is carefully examined. Large amount of energy is produced in the fuel reactor, but energy needs to be supplied to the air reactor. The overall performance and efficiency of the modeled CLC systems are also evaluated.

  8. Continuous hydrothermal co-liquefaction of aspen wood and glycerol with water phase recirculation

    DEFF Research Database (Denmark)

    Pedersen, Thomas H.; Grigoras, Ionela F.; Hoffmann, Julia

    2016-01-01

    Hydrothermal liquefaction is a promising technology for the conversion of a wide range of bio-feedstock into a biocrude; a mixture of chemical compounds that holds the potential for a renewable production of chemicals and fuels. Most research in hydrothermal liquefaction is performed in batch type...... reactors, although a continuous and energy-efficient operation is paramount for such process to be feasible. In this work an experimental campaign in a continuous bench scale unit is presented. The campaign is based on glycerol-assisted hydrothermal liquefaction of aspen wood carried out with the presence...... successfully at steady state conditions without any observation of system malfunctioning. The biocrude obtained was characterized using several analytical methods to evaluate the feasibility of the process and the quality of the product. Results showed that a high quality biocrude was obtained having a higher...

  9. Simulation and validation of chemical-looping combustion using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Ling Zhou, Zheming Zhang, Ramesh K. Agarwal

    2014-01-01

    Full Text Available Laboratory-scale experimental studies have demonstrated that Chemical-Looping Combustion (CLC is an advanced technology which holds great potential for high-efficiency low-cost carbon capture. The generated syngas in CLC is subsequently oxidized to CO2 and H2O by reaction with an oxygen carrier. In this paper, process-level models of CLC are established in ASPEN Plus code for detailed simulations. The entire CLC process, from the beginning of coal gasification to reduction and oxidation of the oxygen carrier is modeled. The heat content of each major component such as fuel and air reactors and air/flue gas heat exchangers is carefully examined. Large amount of energy is produced in the fuel reactor, but energy needs to be supplied to the air reactor. The overall performance and efficiency of the modeled CLC systems are also evaluated.

  10. Changes in the microstructure and properties of aspen chemithermomechanical pulp fibres during recycling.

    Science.gov (United States)

    Fu, Yingjuan; Wang, Rongrong; Li, Dejuan; Wang, Zhaojiang; Zhang, Fengshan; Meng, Qinglin; Qin, Menghua

    2015-03-06

    The effects of recycling on the microstructure and properties of bleached aspen chemithermomechanical pulp (CTMP) fibres were systematically investigated. The low-temperature nitrogen adsorption and atomic force microscopy results showed that a substantial amount of large pores and most of the very small pores in the fibre wall closed and the fibre surface became less coarse and porous during recycling. The partial cocrystallisation of cellulose microfibrils took place, as reflected in the increment of the cellulose crystallinity and the width of the crystallite in the 0 0 2 lattice plane. These irreversible structural changes caused significant hornification of the recycled fibres, leading to the loss of swelling and bonding capability. The decrease of the tensile index, burst index, and tear index further demonstrated the deterioration of the fibre properties. However, the single-fibre strength considerably increased after recycling, which was mainly due to the enlarged cellulose aggregates in the fibre wall.

  11. Three Stage Equilibrium Model for Coal Gasification in Entrained Flow Gasifiers Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    KONG Xiangdong; ZHONG Weimin; DU Wenli; QIAN Feng

    2013-01-01

    A three stage equilibrium model is developed for coal gasification in the Texaco type coal gasifiers based on Aspen Plus to calculate the composition of product gas,carbon conversion,and gasification temperature.The model is divided into three stages including pyrolysis and combustion stage,char gas reaction stage,and gas phase reaction stage.Part of the water produced in the pyrolysis and combustion stage is assumed to be involved in the second stage to react with the unburned carbon.Carbon conversion is then estimated in the second stage by steam participation ratio expressed as a function of temperature.And the gas product compositions are calculated from gas phase reactions in the third stage.The simulation results are consistent with published experimental data.

  12. 美国 ACUSON ASPEN SN31893彩超特殊故障 1例

    Institute of Scientific and Technical Information of China (English)

    张涛

    2001-01-01

    @@美国 ASPEN SN31893彩超系美国 ACUSON公司的最新一代产品,为新一代全功能彩超,该机型在部队医院拥有量较大,据对经销商了解还没有出现过类似的故障。 故障现象 开机后机器开始自检, 4MB DRAM OK。然后是 ACUSON ASPEN的杉树图象出现,机器进入 POWER DIAGNOSTICS,一段时间后出现错误提示:

  13. The Aspen Framework for Dark Matter Substructure Inference from Strong Gravitational Lensing Observations

    Science.gov (United States)

    Moustakas, Leonidas A.; Cyr-Racine, Francis-Yan; Keeton, Charles R.

    2016-01-01

    The properties of the dark matter particle or particles lead to different small scale halo populations, distributions, and evolution over cosmic time. We introduce a new method for characterizing the properties of substructure within galaxies through the power spectrum of potential fluctuations, and demonstrate how complete sets of multiwavelength imaging and time domain observations can be processed directly to infer all facets of the strong gravitational lensing components and source properties, including the dark matter substructure power spectrum constraints. We are able to take advantage of analysis parallels with cosmic background radiation techniques, and furthermore demonstrate how this technique, dubbed The Aspen Framework, reduces to the long-standing approach of working with reduced or derived observable quantities in lensing.

  14. Aspen Global Change Institute: 25 Years of Interdisciplinary Global Change Science

    Energy Technology Data Exchange (ETDEWEB)

    Meehl, Gerald A.; Moss, Richard

    2016-11-01

    Global environmental changes such as climate change result from the interaction of human and natural systems. Research to understand these changes and options for addressing them requires the physical, environmental, and social sciences, as well as engineering and other applied fields. In this essay, we describe how the Aspen Global Change Institute (AGCI) has provided leadership in global change science over the past 25 years—in particular how it has contributed to the integration of the natural and social sciences needed to research the drivers of change, Earth system response, natural and human system impacts, and options for risk management. We illustrate the ways the history of AGCI has been intertwined with the evolution of global change science as it has become an increasingly interdisciplinary endeavor.

  15. Carbohydrate reactions during high-temperature steam treatment of aspen wood.

    Science.gov (United States)

    Li, Jiebing; Henriksson, Gunnar; Gellerstedt, Göran

    2005-06-01

    Aspen wood was treated with steam at different time-temperature severity factors. Analysis of the amounts of acids released revealed a relationship between the acidity and the formation of furfural and hydroxymethyl furfural as degradation products from carbohydrates. It is suggested that two concurrent or consecutive mechanisms are responsible for the observed results: a homolytic cleavage and an acid hydrolysis of glucosidic linkages in the polysaccharides. By preimpregnating the wood with alkali, hydrolysis can be eliminated, resulting in a much cleaner depolymerization of the polysaccharides without any further acid-catalyzed degradation. The enzymatic digestibility of the steam-treated wood material for the formation of glucose was compared with that of steam-exploded wood. A more efficient route for glucose production from steam-exploded wood was found as long as the biomass-pretreated material was homogeneous and without shives.

  16. Process simulation of oxy-combustion for maximization of energy output using ASPEN plus

    Directory of Open Access Journals (Sweden)

    Subhodeep Banerjee, Xiao Zhang, Suraj K. Puvvada, Ramesh K. Agarwal

    2014-01-01

    Full Text Available Oxy-fuel combustion is a next-generation combustion technology that shows promise to address the need of low-cost carbon capture from fossil fueled power plants. Oxy-fuel combustion requires expensive pre-processing in an air separation unit to separate pure oxygen from air for the combustion process, which reduces the overall efficiency of the process. This paper employs ASPEN Plus process simulation software to model a simple oxy-fuel combustor and investigates the effect of various parameters on the energy output. The composition of the flue gas is carefully examined. The results of this study provide a starting point for optimized oxy-fuel combustion operation for maximum energy output, which will be crucial for future deployment of oxy-fuel combustion technology.

  17. Knockdown of a Laccase in Populus deltoides Confers Altered Cell Wall Chemistry and Increased Sugar Release

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Anthony C.; Jawdy, Sara; Gunter, Lee; Gjersing, Erica; Sykes, Robert; Hinchee, Maud A. W.; Winkeler, Kimberly A.; Collins, Cassandra M.; Engle, Nancy; Tschaplinski, Timothy J.; Yang, Xiaohan; Tuskan, Gerald A.; Muchero, Wellington; Chen, Jin-Gui

    2016-10-01

    Plant laccases are thought to function in the oxidation of monolignols which leads to higher order lignin formation. Only a hand-full of laccases in plants have been functionally evaluated and as such little is known about the breadth of their impact on cell wall chemistry or structure. Here we describe a previously uncharacterized laccase from Populus, encoded by locus Potri.008G064000, whose reduced expression resulted in transgenic Populus trees with changes in syringyl/guaiacyl (S/G) ratios as well as altered sugar release phenotypes. These phenotypes are consistent with plant biomass exhibiting reduced recalcitrance. Interestingly, the transgene effect on recalcitrance is dependent on a mild pretreatment prior to chemical extraction of sugars. Metabolite profiling suggests the transgene modulates phenolics that are associated with the cell wall structure. We propose that this particular laccase has a range of functions related to oxidation of phenolics and conjugation of flavonoids that interact with lignin in the cell wall.

  18. Biochemical basis of drought tolerance in hybrid Populus grown under field production conditions. CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Tschaplinski, T.J.; Tuskan, G.A. [Oak Ridge National Lab., TN (United States); Wierman, C. [Boise Cascade Corp., Wallula, WA (United States)

    1997-04-01

    The purpose of this cooperative effort was to assess the use of osmotically active compounds as molecular selection criteria for drought tolerance in Populus in a large-scale field trial. It is known that some plant species, and individuals within a plant species, can tolerate increasing stress associated with reduced moisture availability by accumulating solutes. The biochemical matrix of such metabolites varies among species and among individuals. The ability of Populus clones to tolerate drought has equal value to other fiber producers, i.e., the wood products industry, where irrigation is used in combination with other cultural treatments to obtain high dry weight yields. The research initially involved an assessment of drought stress under field conditions and characterization of changes in osmotic constitution among the seven clones across the six moisture levels. The near-term goal was to provide a mechanistic basis for clonal differences in productivity under various irrigation treatments over time.

  19. Cytogenetic analysis of Populus trichocarpa--ribosomal DNA, telomere repeat sequence, and marker-selected BACs.

    Science.gov (United States)

    Islam-Faridi, M N; Nelson, C D; DiFazio, S P; Gunter, L E; Tuskan, G A

    2009-01-01

    The 18S-28S rDNA and 5S rDNA loci in Populus trichocarpa were localized using fluorescent in situ hybridization (FISH). Two 18S-28S rDNA sites and one 5S rDNA site were identified and located at the ends of 3 different chromosomes. FISH signals from the Arabidopsis-type telomere repeat sequence were observed at the distal ends of each chromosome. Six BAC clones selected from 2 linkage groups based on genome sequence assembly (LG-I and LG-VI) were localized on 2 chromosomes, as expected. BACs from LG-I hybridized to the longest chromosome in the complement. All BAC positions were found to be concordant with sequence assembly positions. BAC-FISH will be useful for delineating each of the Populus trichocarpa chromosomes and improving the sequence assembly of this model angiosperm tree species.

  20. Cytogenetic Analysis of Populus trichocarpa - Ribosomal DNA, Telomere Repeat Sequence, and Marker-selected BACs

    Energy Technology Data Exchange (ETDEWEB)

    Tuskan, Gerald A [ORNL; Gunter, Lee E [ORNL; DiFazio, Stephen P [West Virginia University

    2009-01-01

    The 18S-28S rDNA and 5S rDNA loci in Populus trichocarpa were localized using fluorescent in situ hybridization (FISH). Two 18S-28S rDNA sites and one 5S rDNA site were identified and located at the ends of 3 different chromosomes. FISH signals from the Arabidopsis -type telomere repeat sequence were observed at the distal ends of each chromosome. Six BAC clones selected from 2 linkage groups based on genome sequence assembly (LG-I and LG-VI) were localized on 2 chromosomes, as expected. BACs from LG-I hybridized to the longest chromosome in the complement. All BAC positions were found to be concordant with sequence assembly positions. BAC-FISH will be useful for delineating each of the Populus trichocarpa chromosomes and improving the sequence assembly of this model angiosperm tree species.

  1. NON DESTRUCTIVE EVALUATION OF HEARTWOOD DIAMETER AT BREAST HEIGHT FOR EUCALYPTUS GLOBULUS AND POPULUS EURAMERICANA HYBRID

    Directory of Open Access Journals (Sweden)

    Hugo Alexandre Jóia

    2006-12-01

    Full Text Available The objective of this study was the evaluation of the heartwood diameter (dcerne at breast height on stand trees, for Eucalyptus globulus Labill and the hybrid Populus euramericana. The data used was collected in eucalyptus and popular pure plantations in Central and North Portugal.The non destructive methods tested in the evaluation of heartwood diameter at breast height were [1] visual identification of the heartwood on core samples and [2] indirect estimation using mathematic models. The results allow to consider that visual determination of dcerne is appropriate for Populus, and development of prediction models based diameter at breast height (d, total height (h and age (t, give better results for eucalyptus.

  2. Knockdown of a laccase in Populus deltoides confers altered cell wall chemistry and increased sugar release.

    Science.gov (United States)

    Bryan, Anthony C; Jawdy, Sara; Gunter, Lee; Gjersing, Erica; Sykes, Robert; Hinchee, Maud A W; Winkeler, Kimberly A; Collins, Cassandra M; Engle, Nancy; Tschaplinski, Timothy J; Yang, Xiaohan; Tuskan, Gerald A; Muchero, Wellington; Chen, Jin-Gui

    2016-10-01

    Plant laccases are thought to function in the oxidation of monolignols which leads to higher order lignin formation. Only a hand-full of laccases in plants have been functionally evaluated, and as such little is known about the breadth of their impact on cell wall chemistry or structure. Here, we describe a previously uncharacterized laccase from Populus, encoded by locus Potri.008G064000, whose reduced expression resulted in transgenic Populus trees with changes in syringyl/guaiacyl ratios as well as altered sugar release phenotypes. These phenotypes are consistent with plant biomass exhibiting reduced recalcitrance. Interestingly, the transgene effect on recalcitrance is dependent on a mild pretreatment prior to chemical extraction of sugars. Metabolite profiling suggests the transgene modulates phenolics that are associated with the cell wall structure. We propose that this particular laccase has a range of functions related to oxidation of phenolics and conjugation of flavonoids that interact with lignin in the cell wall.

  3. NON DESTRUCTIVE EVALUATION OF HEARTWOOD DIAMETER AT BREAST HEIGHT FOR EUCALYPTUS GLOBULUS AND POPULUS EURAMERICANA HYBRID

    OpenAIRE

    Hugo Alexandre Jóia; Teresa Fonseca; Maria Emília Silva; Carlos Pacheco Marques

    2006-01-01

    The objective of this study was the evaluation of the heartwood diameter (dcerne) at breast height on stand trees, for Eucalyptus globulus Labill and the hybrid Populus euramericana. The data used was collected in eucalyptus and popular pure plantations in Central and North Portugal.The non destructive methods tested in the evaluation of heartwood diameter at breast height were [1] visual identification of the heartwood on core samples and [2] indirect estimation using mathematic models. The...

  4. Successful Agrobacterium-mediated transformation of Populus tomentosa with apple SPDS gene

    Institute of Scientific and Technical Information of China (English)

    LIU Ting-ting; PANG Xiao-ming; LONG Cui; ZHANG Zhi-yi

    2008-01-01

    The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase (SPDS) genes derived from an apple by an Agrobacterium-mediatod method. Four transgenic clones were confirmed by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR.

  5. Palaeogene fossil Populus leaves from Lanzhou Basin and their palaeoclimatic significance

    Institute of Scientific and Technical Information of China (English)

    SUN Bainian; YAN Defei; XIE Sanping; CONG Peiyun; XIN Cunlin; YUN Fei

    2004-01-01

    An angiosperm compression flora is found in Palaeogene from Lanzhou Basin and the cuticular analysis of Populus davidiana Dode in the flora is carefully made. Furthermore, the fossil cuticles are compared with the epidermal structures of extant Populus leaves growing in different environments, I.e. Moist, semimoist, and semiarid to arid climatic regions. The present experiments indicate that mature leaves of P. Davidiana show leaf size from big to small, leaf cuticles from thick to thin and anticlinal walls of epidermal cells from faintness to clarity along with the increase of latitudes of the plant distributions, the climatic variation from moist to arid, the annual precipitation from more to less and the annual mean temperature from high to low. The fossil P.davidiana differs from the specimens collected from Shandan in semiarid to arid climatic regions but closely resembles the Wushan leaves in a semi-moist climatic area in a lot of features. In a word, the new research may reflect that the flora lives in a semi-moist climatic environment. The present discovery of compression of Paleogene Populus davidiana is of great significance to studying vegetation types, climatic and environmental changes during the primal uplifting of the Qinghai-Tibet Plateau.

  6. Isolation and characterization of cDNAs encoding leucoanthocyanidin reductase and anthocyanidin reductase from Populus trichocarpa.

    Directory of Open Access Journals (Sweden)

    Lijun Wang

    Full Text Available Proanthocyanidins (PAs contribute to poplar defense mechanisms against biotic and abiotic stresses. Transcripts of PA biosynthetic genes accumulated rapidly in response to infection by the fungus Marssonina brunnea f.sp. multigermtubi, treatments of salicylic acid (SA and wounding, resulting in PA accumulation in poplar leaves. Anthocyanidin reductase (ANR and leucoanthocyanidin reductase (LAR are two key enzymes of the PA biosynthesis that produce the main subunits: (+-catechin and (--epicatechin required for formation of PA polymers. In Populus, ANR and LAR are encoded by at least two and three highly related genes, respectively. In this study, we isolated and functionally characterized genes PtrANR1 and PtrLAR1 from P. trichocarpa. Phylogenetic analysis shows that Populus ANR1 and LAR1 occurr in two distinct phylogenetic lineages, but both genes have little difference in their tissue distribution, preferentially expressed in roots. Overexpression of PtrANR1 in poplar resulted in a significant increase in PA levels but no impact on catechin levels. Antisense down-regulation of PtrANR1 showed reduced PA accumulation in transgenic lines, but increased levels of anthocyanin content. Ectopic expression of PtrLAR1 in poplar positively regulated the biosynthesis of PAs, whereas the accumulation of anthocyanin and flavonol was significantly reduced (P<0.05 in all transgenic plants compared to the control plants. These results suggest that both PtrANR1 and PtrLAR1 contribute to PA biosynthesis in Populus.

  7. Association genetics and expression patterns of a CBF4 homolog in Populus under abiotic stress.

    Science.gov (United States)

    Li, Ying; Xu, Baohua; Du, Qingzhang; Zhang, Deqiang

    2015-06-01

    New strategies for prevention and treatment of abiotic stress require an improved understanding of stress responses. Here, we examined response differences of a C-repeat binding factor gene (PsCBF4) between five species in the genus Populus. We also used a candidate gene-based approach to identify single nucleotide polymorphisms (SNPs) within PsCBF4 that were associated with physiological and biochemical traits in a natural population (528 unrelated individuals) of Populus simonii. We first isolated a 1,044-bp PsCBF4 cDNA encoding a polypeptide of 256 amino acids. Expression profiling revealed that CBF4 is differentially expressed under cold, heat, drought, and salt conditions among five Populus species. Cold stress is the most significant interspecific difference, and PsCBF4 transcript levels ranged from 6.5 to 379.5 times higher than in unstressed controls. A natural population of P. simonii showed high nucleotide diversity (π T = 0.00880, θ w = 0.01192) and low linkage disequilibrium (r (2) ≥ 0.1, within 700 bp) across PsCBF4. Association analysis showed that nine SNPs (false discovery rate Q stress tolerance in P. simonii.

  8. Estimating Stem Volume Using QuickBird Imagery and Allometric Relationships for Open Populus xiaohei Plantations

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qing Wang; Zeng-Yuan Li; Xing-E Liu; Guang Deng; Ze-Hui Jiang

    2007-01-01

    There has been a great deal of interest in studying the crown of trees using remote sensing data. In this study, crown width was extracted from high-resolution QuickBird images for open Populus xiaohei plantations. Regression models for predicting the individual stem volumes of Populus xiaohei were established using extracted crown width, as well as estimated tree parameters (i.e. diameter at breast height [DBH] and tree height) as predictors. Our results indicated that crown width could be accurately extracted from QuickBird images using a multi-scale segmentation approach with a mean relative error of 5.74%, especially for wide-spacing stands. Using either extracted crown width alone or with estimated DBH and tree height can successfully estimate individual stem volume of Populus xiaohei with the R2 value ranging from 0.87 to 0.92 depending on different model forms. In particular, the two second-order polynomial models (model2 and model 6), based on QuickBird image-derived crown widths and estimated DBH and tree heights, respectively, were the best at describing the relationship between stem volume and tree characteristics.

  9. Short-day treatment during the growing period limits shoot growth and increases frost hardiness of hybrid aspen plants in the nursery

    Institute of Scientific and Technical Information of China (English)

    Zhang Gang; Jaana Luoranen; Heikki Smolander

    2007-01-01

    In Finland, under nursery conditions hybrid aspen may continue their shoot growth until early September. Thus,frost hardening is usually delayed. To solve this problem, We used a three-week period of short-day (SD) treatment between late July and mid-August. During autumn after frost exposure,frost hardiness (FH) Was assessed three times with a stem-browning test. The resuits showed that after SD treatment shoot growth ceased and FH increased when compared to untreated hybrid aspen. Furthermore,the height of SD-treated hybrid aspen varied much less than that of the control plants. We conclude that SD treatment in the nursery during the growing period can be used as a supplementary method for producing well-hardened and uniform hybrid aspen plants.

  10. Common trade-offs between xylem resistance to cavitation and other physiological traits do not hold among unrelated Populus deltoides x Populus nigra hybrids.

    Science.gov (United States)

    Fichot, Régis; Barigah, Têtè S; Chamaillard, Sylvain; LE Thiec, Dider; Laurans, Françoise; Cochard, Hervé; Brignolas, Franck

    2010-09-01

    We examined the relationships between xylem resistance to cavitation and 16 structural and functional traits across eight unrelated Populus deltoides x Populus nigra genotypes grown under two contrasting water regimes. The xylem water potential inducing 50% loss of hydraulic conductance (Psi(50)) varied from -1.60 to -2.40 MPa. Drought-acclimated trees displayed a safer xylem, although the extent of the response was largely genotype dependent, with Psi(50) being decreased by as far as 0.60 MPa. At the tissue level, there was no clear relationship between xylem safety and either xylem water transport efficiency or xylem biomechanics; the only structural trait to be strongly associated with Psi(50) was the double vessel wall thickness, genotypes exhibiting a thicker double wall being more resistant. At the leaf level, increased cavitation resistance was associated with decreased stomatal conductance, while no relationship could be identified with traits associated with carbon uptake or bulk leaf carbon isotope discrimination, a surrogate of intrinsic water-use efficiency. At the whole-plant level, increased safety was associated with higher shoot growth potential under well-irrigated regime only. We conclude that common trade-offs between xylem resistance to cavitation and other physiological traits that are observed across species may not necessarily hold true at narrower scales.

  11. 训练剂-1工艺过程的Aspen Plus全流程模拟%Simulation of the whole production process of training agent-1 using Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    盖希杰; 邓德茹; 刘兴红; 王志甄

    2010-01-01

    建立了训练剂-1间歇工艺过程的数学模型,利用流程模拟软件Aspen Plus内置的物性资源、物性估算和实验数据回归的方法,弥补了实验数据的不足.以工艺过程机理和间歇过程数学模型为基础,采用Aspen Plus软件对训练剂-1间歇工艺过程全流程进行了模拟,模拟结果与实际工艺系统运行情况吻合良好.

  12. Aspen Plus在制药化工原理汽液平衡教学中的应用%Applications of Aspen Plus in the Vapor-liquid Equilibrium Teaching of Pharmaceutical and Chemical Engineering Principles

    Institute of Scientific and Technical Information of China (English)

    王贤书

    2011-01-01

    介绍了Aspen Plus化工流程模拟软件的一般使用方法,结合本人在山苍子油蒸馏分离模拟计算方面的科研成果,探讨了Aspen Plus软件在《制药化工原理》汽液平衡教学中的应用.实践表明,采用流程模拟软件辅助制药化工原理教学的方法,不仅有助于培养学生的兴趣和拓宽学生的视野,使学生加深了对汽液平衡内容的深刻理解,而且有助于培养学生利用流程模拟技术解决工程实际问题的能力.

  13. 基于 Aspen Plus 软件的磨煤干燥过程模拟与分析%Simulation and Analyzsis of the Coal Grinding and Drying Process with the Aspen Plus Software

    Institute of Scientific and Technical Information of China (English)

    周春平; 甘丹; 严应群

    2014-01-01

    After simulating and analyzing the coal grinding and drying process with the Aspen Plus software ,know accurately the utilities consumption which including the fuel gas ,low pressure nitrogen gas ,combustion air ,dilution air and electricity ,etc . Optimizing the drying process could provide guidance for the engineering design and manufacturing operation .%运用Aspen Plus软件对磨煤干燥过程进行模拟与分析,可以比较准确地知道CMD工段的燃料气、低低压氮气、助燃空气、稀释空气、电力等公用工程的消耗,优化干燥工艺流程,为工程设计和生产操作提供指导。

  14. Continuous Extraction and Separation Based on Aspen for the Water of the ISO-Propylene Alcohol-Water%基于Aspen plus异丙醚-异丙醇-水的连续萃取分离

    Institute of Scientific and Technical Information of China (English)

    战俊磊

    2015-01-01

    选用乙二醇(EG)为萃取剂,用Aspen Plus化工模拟软件中的Radfrac单元操作模块,采用UNIFAC物性计算方法,通过优化各参数,在适宜操作条件下,塔顶可以得到高纯度的二异丙醚、异丙醇产品.

  15. Application of ASPEN PLUS Chemical Modeling System in the Process of Fractionation%ASPEN PLUS化工模拟系统在精馏过程中的应用

    Institute of Scientific and Technical Information of China (English)

    刘雨虹

    2003-01-01

    应用ASPEN PLUS化工模拟系统中的RateFrac精馏模块对催化裂化气分工艺中的精馏塔进行模拟,模拟结果与装置原始设计结果吻合,可用于指导生产,并提供装置改造依据.

  16. 化工设计中流程模拟软件Aspen Plus的使用

    Institute of Scientific and Technical Information of China (English)

    彭江

    2015-01-01

    化工设计流程模拟软件是一款集化工设计、动态模拟以及各类计算于一体的极其强大的功能性软件。Aspen Plus在化工设计过程中得到普遍的应用,极大提升了我国化工领域工艺流程等方面的设计效率和水平。为此,本文就以A spen Plus软件的特点和优势进行介绍,并详细说明Aspen Plus在化工设计领域中突出的表现和运用的具体方法。

  17. Implications of Elevated Atmospheric Carbon Dioxide and Tropospheric Ozone for Water Use in Stands of Trembling Aspen and Paper Birch

    Science.gov (United States)

    Rhea, Lee Kirk

    Projected increases in the atmospheric concentration of CO2 and tropospheric O3 over the next 50 years are of concern due in part to their potential to affect forest water budgets. I conducted a series of studies at the Aspen Free Air CO2 and O3 Enrichment experiment near Rhinelander, WI to determine the effect of projected concentrations of these gases for the year 2050 on the water budget in stands of trembling aspen and paper birch. In order to determine the effects of elevated CO2 (eCO 2) and O3 (eO3) on rainfall partitioning between interception, through fall, and stem flow I performed a computerized analysis of photographed canopy branches and compared the results to hydrologic measurements. Elevated O3 significantly decreased total aspen and birch branch length, resulting in net decreases for 2002 whorls of -18 % and 2006 whorls of -16 %. Some of these changes had measurable effects on rainfall partitioning. The biomass of fine roots has been observed to change in response to eCO2 and eO3 at shallow depths, but little work has been done to assess deeper roots. I characterized fine root responses to eCO 2 and eO3 to a depth of one meter. Fumigation with O 3 increased small root biomass in shallow soil 30 % in all aspen plots and decreased root biomass in shallow soil 46 % in aspen-birch plots. Increases in root length up to 131 % and specific root length up to 77 % occurred under eO3 in middle and deep soil layers, indicating more extensive soil exploration at depth. Small root biomass in shallow soils increased 20 % to 24 % under eCO2, indicative of more intensive soil exploration near the surface. Previous studies of sapwood from Aspen-FACE indicated that anatomical structures related to hydraulic conductance (K) differed between aspen clones and that they responded to the treatments differently. I constructed embolism curves for stem wood samples collected below the base of the live crowns. There were no significant treatment effects on K at full water

  18. One-Dimensional Biomass Fast Pyrolysis Model with Reaction Kinetics Integrated in an Aspen Plus Biorefinery Process Model

    Energy Technology Data Exchange (ETDEWEB)

    Humbird, David; Trendewicz, Anna; Braun, Robert; Dutta, Abhijit

    2017-01-27

    A biomass fast pyrolysis reactor model with detailed reaction kinetics and one-dimensional fluid dynamics was implemented in an equation-oriented modeling environment (Aspen Custom Modeler). Portions of this work were detailed in previous publications; further modifications have been made here to improve stability and reduce execution time of the model to make it compatible for use in large process flowsheets. The detailed reactor model was integrated into a larger process simulation in Aspen Plus and was stable for different feedstocks over a range of reactor temperatures. Sample results are presented that indicate general agreement with experimental results, but with higher gas losses caused by stripping of the bio-oil by the fluidizing gas in the simulated absorber/condenser. This integrated modeling approach can be extended to other well-defined, predictive reactor models for fast pyrolysis, catalytic fast pyrolysis, as well as other processes.

  19. Aspen InfoPlus.21实时数据库管理系统的应用

    Institute of Scientific and Technical Information of China (English)

    肖建荣; 万慧芸

    2013-01-01

    To meet the requirement of chemical plant information management, Aspen Infoplus.21 real-time database manage-ment system is constructed based on the current DCS, LIMS and company office LAN. With this network, DCS plant operation re-al-time data information is acquired, monitored and used directly via OPC interface, DCS batch information is acquired, monitored and used directly via Aspen Production Record Manager and Microsoft SQL Server, LIMS data is acquired, monitored and used di-rectly via ODBC interface, and the open framework is developed. With these excellent applications, we have achieved our high work efficiency, and have eventually improved our plant operation effectiveness.%  针对化工厂信息管理的需要,在现有DCS、LIMS和公司局域网(LAN)基础上,搭建Aspen Infoplus.21实时数据库管理系统,通过OPC接口实时读取、监控、查阅和应用DCS系统数据,通过Aspen Production Record Manag-er及Microsoft SQL Server直接抽取DCS工厂批量工艺批次信息,通过ODBC接口及时读取实验室LIMS产品化验数据,并支持开放框架运用。通过实际应用,提高工作效率,最终提高整个工厂生产运作的有效性。

  20. Comparative simulation study of gas-phase propylene polymerization in fluidized bed reactors using aspen polymers and two phase models

    Directory of Open Access Journals (Sweden)

    Shamiria Ahmad

    2013-01-01

    Full Text Available A comparative study describing gas-phase propylene polymerization in fluidized-bed reactors using Ziegler-Natta catalyst is presented. The reactor behavior was explained using a two-phase model (which is based on principles of fluidization as well as simulation using the Aspen Polymers process simulator. The two-phase reactor model accounts for the emulsion and bubble phases which contain different portions of catalysts with the polymerization occurring in both phases. Both models predict production rate, molecular weight, polydispersity index (PDI and melt flow index (MFI of the polymer. We used both models to investigate the effect of important polymerization parameters, namely catalyst feed rate and hydrogen concentration, on the product polypropylene properties, such as production rate, molecular weight, PDI and MFI. Both the two-phase model and Aspen Polymers simulator showed good agreement in terms of production rate. However, the models differed in their predictions for weight-average molecular weight, PDI and MFI. Based on these results, we propose incorporating the missing hydrodynamic effects into Aspen Polymers to provide a more realistic understanding of the phenomena encountered in fluidized bed reactors for polyolefin production.

  1. Geology of the Aspen 15-minute quadrangle, Pitkin and Gunnison counties, Colorado

    Science.gov (United States)

    Bryant, Bruce

    1979-01-01

    The Aspen area, located 170 km southwest of Denver, Colo., lies at the intersection of the northeast-trending Colorado mineral belt and the west margin of the north-trending Sawatch uplift of Laramide age; it is within the southwest part of the northwest-trending late Paleozoic Eagle basin. Precambrian shales and graywackes, perhaps as old as 2 billion years (b.y.), were converted to sillimanite-bearing gneiss and muscovite-biotite schist 1.65-1.70 b.y. ago. They were deformed into northeast-plunging folds and were migmatized, and they were intruded by quartz diorite, porphyritic quartz monzonite, and granite. Muscovite-biotite quartz monzonite intruded this older Precambrian terrane about 1.45 b.y. ago and is the predominant Precambrian rock near Aspen. Uplift, some faulting, and much erosion occurred during the 900-million year (m.y.) interval between emplacement of the plutonic rocks and deposition of Upper Cambrian sediments. From Late Cambrian through Mississippian the region was part of a broad area alternately covered by shallow seas or occupied by low-lying land. Quartzite, dolomite, and limestone 200-320 m thick, comprising the Sawatch Quartzite and Peerless Formation (Cambrian), Manitou Dolomite (Ordovician), Chaffee Group (Mississippian(?) and Devonian), and Leadville Limestone (Mississippian) were deposited during this interval. After an hiatus during which soil formation and solution of the Leadville Limestone took place in the Late Mississippian, a thick sequence of marine and nonmarine clastic rocks was deposited in the newly developing Eagle basin during the late Paleozoic and early Mesozoic. Deposition of about 300 m of carbonaceous shale, limestone, dolomite, and minor siltstone and evaporite of the Belden Formation began in a shallow sea in Early and Middle Pennsylvanian time. Facies relations indicate that the northwest-trending Uncompahgre uplift southwest of Aspen, if present at that time, had very low relief. The overlying Middle

  2. Twenty-One Genome Sequences from Pseudomonas Species and 19 Genome Sequences from Diverse Bacteria Isolated from the Rhizosphere and Endosphere of Populus deltoides

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Steven D [ORNL; Utturkar, Sagar M [ORNL; Klingeman, Dawn Marie [ORNL; Johnson, Courtney M [ORNL; Martin, Stanton [ORNL; Land, Miriam L [ORNL; Lu, Tse-Yuan [ORNL; Schadt, Christopher Warren [ORNL; Doktycz, Mitchel John [ORNL; Pelletier, Dale A [ORNL

    2012-01-01

    To aid in the investigation of the Populus deltoides microbiome we generated draft genome sequences for twenty one Pseudomonas and twenty one other diverse bacteria isolated from Populus deltoides roots. Genome sequences for isolates similar to Acidovorax, Bradyrhizobium, Brevibacillus, Burkholderia, Caulobacter, Chryseobacterium, Flavobacterium, Herbaspirillum, Novosphingobium, Pantoea, Phyllobacterium, Polaromonas, Rhizobium, Sphingobium and Variovorax were generated.

  3. Diversification and expression of the PIN, AUX/LAX and ABCB families of putative auxin transporters in Populus

    Directory of Open Access Journals (Sweden)

    Nicola eCarraro

    2012-02-01

    Full Text Available Intercellular transport of the plant hormone auxin is mediated by three families of membrane-bound protein carriers, with the PIN and ABCB families coding primarily for efflux proteins and the AUX/LAX family coding for influx proteins. In the last decade our understanding of gene and protein function for these transporters in Arabidopsis has expanded rapidly but very little is known about their role in woody plant development. Here we present a comprehensive account of all three families in the model woody species Populus, including chromosome distribution, protein structure, quantitative gene expression, and evolutionary relationships. The PIN and AUX/LAX gene families in Populus comprise 16 and 8 members respectively, and show evidence for the retention of paralogs following a relatively recent whole genome duplication. There is also evidence for differential expression across tissues within many gene pairs. The ABCB family is previously undescribed in Populus and includes 20 members, showing a much deeper evolutionary history including both tandem and whole genome duplication as well as probable loss. A striking number of these transporters are expressed in developing Populus stems and we suggest that evolutionary and structural relationships with known auxin transporters in Arabidopsis can point toward candidate genes for further study in Populus. This is especially important for the ABCBs, which is a large family and includes members in Arabidopsis that are able to transport other substrates in addition to auxin. Protein modeling, sequence alignment and expression data all point to ABCB1.1 as a likely auxin transport protein in Populus. Given that basipetal auxin flow through the cambial zone shapes the development of woody stems, it is important that we identify the full complement of proteins involved in this process. This work should lay the foundation for studies targeting specific proteins for functional characterization and in situ

  4. Diversity of Pseudomonas Genomes, Including Populus-Associated Isolates, as Revealed by Comparative Genome Analysis.

    Science.gov (United States)

    Jun, Se-Ran; Wassenaar, Trudy M; Nookaew, Intawat; Hauser, Loren; Wanchai, Visanu; Land, Miriam; Timm, Collin M; Lu, Tse-Yuan S; Schadt, Christopher W; Doktycz, Mitchel J; Pelletier, Dale A; Ussery, David W

    2015-10-30

    The Pseudomonas genus contains a metabolically versatile group of organisms that are known to occupy numerous ecological niches, including the rhizosphere and endosphere of many plants. Their diversity influences the phylogenetic diversity and heterogeneity of these communities. On the basis of average amino acid identity, comparative genome analysis of >1,000 Pseudomonas genomes, including 21 Pseudomonas strains isolated from the roots of native Populus deltoides (eastern cottonwood) trees resulted in consistent and robust genomic clusters with phylogenetic homogeneity. All Pseudomonas aeruginosa genomes clustered together, and these were clearly distinct from other Pseudomonas species groups on the basis of pangenome and core genome analyses. In contrast, the genomes of Pseudomonas fluorescens were organized into 20 distinct genomic clusters, representing enormous diversity and heterogeneity. Most of our 21 Populus-associated isolates formed three distinct subgroups within the major P. fluorescens group, supported by pathway profile analysis, while two isolates were more closely related to Pseudomonas chlororaphis and Pseudomonas putida. Genes specific to Populus-associated subgroups were identified. Genes specific to subgroup 1 include several sensory systems that act in two-component signal transduction, a TonB-dependent receptor, and a phosphorelay sensor. Genes specific to subgroup 2 contain hypothetical genes, and genes specific to subgroup 3 were annotated with hydrolase activity. This study justifies the need to sequence multiple isolates, especially from P. fluorescens, which displays the most genetic variation, in order to study functional capabilities from a pangenomic perspective. This information will prove useful when choosing Pseudomonas strains for use to promote growth and increase disease resistance in plants.

  5. A novel process simulation model (PSM) for anaerobic digestion using Aspen Plus.

    Science.gov (United States)

    Rajendran, Karthik; Kankanala, Harshavardhan R; Lundin, Magnus; Taherzadeh, Mohammad J

    2014-09-01

    A novel process simulation model (PSM) was developed for biogas production in anaerobic digesters using Aspen Plus®. The PSM is a library model of anaerobic digestion, which predicts the biogas production from any substrate at any given process condition. A total of 46 reactions were used in the model, which include inhibitions, rate-kinetics, pH, ammonia, volume, loading rate, and retention time. The hydrolysis reactions were based on the extent of the reaction, while the acidogenic, acetogenic, and methanogenic reactions were based on the kinetics. The PSM was validated against a variety of lab and industrial data on anaerobic digestion. The P-value after statistical analysis was found to be 0.701, which showed that there was no significant difference between discrete validations and processing conditions. The sensitivity analysis for a ±10% change in composition of substrate and extent of reaction results in 5.285% higher value than the experimental value. The model is available at http://hdl.handle.net/2320/12358 (Rajendran et al., 2013b).

  6. Full employment and competition in the Aspen economic model: implications for modeling acts of terrorism.

    Energy Technology Data Exchange (ETDEWEB)

    Sprigg, James A.; Ehlen, Mark Andrew

    2004-11-01

    Acts of terrorism could have a range of broad impacts on an economy, including changes in consumer (or demand) confidence and the ability of productive sectors to respond to changes. As a first step toward a model of terrorism-based impacts, we develop here a model of production and employment that characterizes dynamics in ways useful toward understanding how terrorism-based shocks could propagate through the economy; subsequent models will introduce the role of savings and investment into the economy. We use Aspen, a powerful economic modeling tool developed at Sandia, to demonstrate for validation purposes that a single-firm economy converges to the known monopoly equilibrium price, output, and employment levels, while multiple-firm economies converge toward the competitive equilibria typified by lower prices and higher output and employment. However, we find that competition also leads to churn by consumers seeking lower prices, making it difficult for firms to optimize with respect to wages, prices, and employment levels. Thus, competitive firms generate market ''noise'' in the steady state as they search for prices and employment levels that will maximize profits. In the context of this model, not only could terrorism depress overall consumer confidence and economic activity but terrorist acts could also cause normal short-run dynamics to be misinterpreted by consumers as a faltering economy.

  7. Thermochemical Equilibrium Model of Synthetic Natural Gas Production from Coal Gasification Using Aspen Plus

    Directory of Open Access Journals (Sweden)

    Rolando Barrera

    2014-01-01

    Full Text Available The production of synthetic or substitute natural gas (SNG from coal is a process of interest in Colombia where the reserves-to-production ratio (R/P for natural gas is expected to be between 7 and 10 years, while the R/P for coal is forecasted to be around 90 years. In this work, the process to produce SNG by means of coal-entrained flow gasifiers is modeled under thermochemical equilibrium with the Gibbs free energy approach. The model was developed using a complete and comprehensive Aspen Plus model. Two typical technologies used in entrained flow gasifiers such as coal dry and coal slurry are modeled and simulated. Emphasis is put on interactions between the fuel feeding technology and selected energy output parameters of coal-SNG process, that is, energy efficiencies, power, and SNG quality. It was found that coal rank does not significantly affect energy indicators such as cold gas, process, and global efficiencies. However, feeding technology clearly has an effect on the process due to the gasifying agent. Simulations results are compared against available technical data with good accuracy. Thus, the proposed model is considered as a versatile and useful computational tool to study and optimize the coal to SNG process.

  8. Stress Responsive Zinc-finger Protein Gene of Populus euphratica in Tobacco Enhances Salt Tolerance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Populus euphratica stress responsive zinc-finger protein gene PSTZ, which encodes a protein including typical Cys2/His2 zinc finger structure, was isolated by reverse transcription-polymerase chain reaction from P. euphratica.Northern hybridization revealed that its expression was induced under drought and salt stress conditions. To examine its function, cDNA of the PSTZ gene, driven by the cauliflower mosaic virus 35S promoter, was cloned into a plant expression vector pBin438 and introduced into tobacco plants. Transgenic tobacco showed an enhanced salt tolerance, suggesting that PSTZ may play a role in plant responsiveness to salt stress.

  9. Effects of antibiotics on plantlet regeneration via organogenesis in Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Ding Xia; Chen Xiao-yang; Li Wei; Du Zhi-yan

    2006-01-01

    Four antibiotics, kanamycin, geneticin, carbenicillin and cefotaxime, were evaluated for their effect on the regeneration of adventitious buds, shoot differentiation, rooting from regenerated shoots of Populus euphratica as well as on their control of Agrobacterium-mediated transformations. Results showed that the optimum concentration ranges of kanamycin and geneticin were 15-20 and 10-15 mg·L-1 at the stage of transgenic plantlet selection. The inhibitory effects of cefotaxime and carbenicillin varied among different genotypes of Agrobacterium. The inhibition of cefotaxime on Agrobacterium C58 was stronger than that of carbenicillin.LBA4404 and their optimum concentrations were both 150 mg·L-1.

  10. Metabolic profiling reveals altered sugar and secondary metabolism in response to UGPase overexpression in Populus

    OpenAIRE

    2014-01-01

    Background UDP-glucose pyrophosphorylase (UGPase) is a sugar-metabolizing enzyme (E.C. 2.7.7.9) that catalyzes a reversible reaction of UDP-glucose and pyrophosphate from glucose-1-phosphate and UTP. UDP-glucose is a key intermediate sugar that is channeled to multiple metabolic pathways. The functional role of UGPase in perennial woody plants is poorly understood. Results We characterized the functional role of a UGPase gene in Populus deltoides, PdUGPase2. Overexpression of the native gene ...

  11. Erfassung, Identifizierung, Vermehrung und Wiederansiedlung der Schwarzpappel Populus nigra in Sachsen-Anhalt

    OpenAIRE

    2013-01-01

    Durch den Flußlauf der Elbe und ihre Nebenflüsse sind in Sachsen-Anhalt aktuelle und potentielle Vorkommensgebiete der Schwarzpappel (Populus nigra) vorhanden. Die natürlichen Standorte der Schwarzpappel sind die Übergangszonen von Weichholzund Hartholzaue (ELLENBERG 1996), wie sie an naturnahen Flußufern zu finden sind. Im Gegensatz zu anderen Baumarten erträgt die Schwarzpappel wie auch Baumweidenarten Hochwasserstände von bis zu 90 Tagen und damit mittlere Hochwässer. Auf Grund der Konkurr...

  12. Commercial wood of clones of genus Populus: Relationship between growth and density of wood with inorganic nutrients

    OpenAIRE

    Senisterra, Gabriela; Marlats, Raúl M.; Ducid, María G.

    2008-01-01

    El objetivo del trabajo fue determinar sobre 10 clones de álamos, provenientes de cruzamientos intraespecíficos de Populus deltoides e interespecíficos de Populus x canadensis, implantados en Teodelina, Santa Fe, Argentina (34°09' S; 61°15' W), la concentración de nutrientes inorgánicos en su corteza y leño, y sus relaciones con los volúmenes comerciales alcanzados a los 9 años de edad y la densidad bási...

  13. Allometries for Widely Spaced Populus ssp. and Betula ssp. in Nurse Crop Systems

    Directory of Open Access Journals (Sweden)

    Hendrik Stark

    2013-11-01

    Full Text Available Nurse crops of widely spaced pioneer trees are a silvicultural approach to protect the regeneration of frost sensitive target tree species. If overstorey nurse crops are harvested, they can provide additional short-term benefits through increased biomass production, e.g., for bioenergy. However, the intensification of biomass exports from forests might impact negatively on ecosystem nutrient pools. Thus, precise allometric biomass equations are required to quantify biomass and nutrient removals. Since an analysis of published allometric equations developed for typical, dense aspen or birch forests showed that the tree height-to-diameter ratio correlated positively and the proportion of branch biomass negatively with stand density, we developed new allometric biomass equations for widely spaced aspen and birch growing at 4 x 4 m spacing. These equations yielded a root mean squared error of 13% when predicting total aboveground woody biomass for our sample trees. In contrast, the corresponding root mean squared error produced by allometric biomass equations from the literature ranged between 17% to 106% of actual dry biomass. Our results show that specific allometric biomass equations are needed for widely spaced pioneer trees both for accurate estimates of biomass and the nutrients contained within.

  14. Importance of two consecutive methionines at the N-terminus of a cellulose synthase (PtdCesA8A) for normal wood cellulose synthesis in aspen.

    Science.gov (United States)

    Liu, Yunxia; Xu, Fuyu; Gou, Jiqing; Al-Haddad, Jameel; Telewski, Frank W; Bae, Hyeun-Jong; Joshi, Chandrashekhar P

    2012-11-01

    All known orthologs of a secondary wall-associated cellulose synthase (CesA) gene from Arabidopsis, AtCesA8, encode CesA proteins with two consecutive methionines at their N-termini (MM or 2M). Here, we report that these 2Ms in an aspen ortholog of AtCesA8, PtdCesA8A, are important for maintaining normal wood cellulose biosynthesis in aspen trees. Overexpression of an altered PtdCesA8A cDNA encoding a PtdCesA8A protein missing one methionine at the N-terminus (1M) in aspen resulted in substantial decrease in cellulose content and caused negative effects on wood strength, suggesting that both methionines are essential for proper CesA expression and function in developing xylem tissues. Transcripts from a pair of paralogous native PtdCesA8 genes, as well as introduced PtdCesA8A:1M transgenes were significantly reduced in developing xylem tissues of transgenic aspen plants, suggestive of a co-suppression event. Overexpression of a native PtdCesA8A cDNA encoding a CesA protein with 2Ms at the N-terminus did not cause any such phenotypic changes. These results suggest the importance of 2Ms present at the N-terminus of PtdCesA8A protein during cellulose synthesis in aspen.

  15. Degradation of Populus euphratica community in the lower reaches of the Tarim River, Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    LIU Jia-zhen; CHEN Ya-ning; CHEN Yong-jin; ZHANG Na; LI Wei-hong

    2005-01-01

    To investigate the relationships between the degradation of plant community and groundwater level in the lower reaches of the Tarim River, nine monitored sections were set along the main stream, where there had been no runoff for nearly 30 years. The characteristics of plant communities were analyzed. It was found that the coverage of trees gradually decreased along the groundwater depth gradient, while the coverage of shrubs slightly increased rather than decreased at first and then gradually decreased, and the coverage of herbs steadily decreased at the beginning and then quickly decreased. The species diversity and species richness of both herbs and woody plants showed obvious degrading trends, while the variations in species evenness were slight. The degrading sequences of species were related to their physiological and ecological characteristics, especially their sensitivity to changes of groundwater table. The herbs with shallow roots first degenerated or disappeared when the groundwater table fell, and then did the deep-rooted herbs, and finally the trees and shrubs with strong tolerance to drought degenerated. The Populus euphratica communities showed typical degrading characteristics, namely the dominant species Populus euphratica remained its dominant status during the degradation. Overall, the existence of strongly tolerant-drought species was the obvious indication of plant species degradation; while simplification of community structure and the decrease of species richness were the obvious indication of plant community degradation.

  16. Populus trichocarpa cell wall chemistry and ultrastructure trait variation, genetic control and genetic correlations.

    Science.gov (United States)

    Porth, Ilga; Klápště, Jaroslav; Skyba, Oleksandr; Lai, Ben S K; Geraldes, Armando; Muchero, Wellington; Tuskan, Gerald A; Douglas, Carl J; El-Kassaby, Yousry A; Mansfield, Shawn D

    2013-02-01

    The increasing ecological and economical importance of Populus species and hybrids has stimulated research into the investigation of the natural variation of the species and the estimation of the extent of genetic control over its wood quality traits for traditional forestry activities as well as the emerging bioenergy sector. A realized kinship matrix based on informative, high-density, biallelic single nucleotide polymorphism (SNP) genetic markers was constructed to estimate trait variance components, heritabilities, and genetic and phenotypic correlations. Seventeen traits related to wood chemistry and ultrastructure were examined in 334 9-yr-old Populus trichocarpa grown in a common-garden plot representing populations spanning the latitudinal range 44° to 58.6°. In these individuals, 9342 SNPs that conformed to Hardy-Weinberg expectations were employed to assess the genomic pair-wise kinship to estimate narrow-sense heritabilities and genetic correlations among traits. The range-wide phenotypic variation in all traits was substantial and several trait heritabilities were > 0.6. In total, 61 significant genetic and phenotypic correlations and a network of highly interrelated traits were identified. The high trait variation, the evidence for moderate to high heritabilities and the identification of advantageous trait combinations of industrially important characteristics should aid in providing the foundation for the enhancement of poplar tree breeding strategies for modern industrial use.

  17. Differential detection of genetic Loci underlying stem and root lignin content in Populus.

    Directory of Open Access Journals (Sweden)

    Tongming Yin

    Full Text Available In this study, we established a comprehensive genetic map with a large number of progeny from a three-generation hybrid Populus intercross, and phenotyped the lignin content, S/G ratio and 28 cell wall subcomponents both in stems and roots for the mapping individuals. Phenotypic analysis revealed that lignin content and syringyl-to-guaiacyl (S/G ratio using pyrolysis molecular beam mass spectroscopy (pyMBMS varied among mapping individuals. Phenotypic analysis revealed that stem lignin content is significantly higher than that in root and the quantified traits can be classified into four distinct groups, with strong correlations observed among components within organs. Altogether, 179 coordinating QTLs were detected, and they were co-localized into 49 genetic loci, 27 of which appear to be pleiotropic. Many of the detected genetic loci were detected differentially in stem and root. This is the first report of separate genetic loci controlling cell wall phenotypes above and below ground. These results suggest that it may be possible to modify lignin content and composition via breed and/or engineer as a means of simultaneously improving Populus for cellulosic ethanol production and carbon sequestration.

  18. Hot water and dilute acid pretreatment of high and low specific gravity Populus deltoides clones.

    Science.gov (United States)

    Martin, Elizabeth M; Bunnell, Kris A; Lau, Ching-Shuan; Pelkki, Matthew H; Patterson, David W; Clausen, Edgar C; Smith, James A; Carrier, Danielle Julie

    2011-02-01

    Populus sp. are hardwood feedstocks that grow in forest management areas that are logged for softwoods; however, they are also being considered as an energy-destined feedstock. The objective of this work was to determine the effect of xylose yield from dilute acid and hot water pretreatments performed in unstirred batch stainless steel reactors at temperatures ranging from 140 to 200°C. Populus deltoides clones S13C20 and S7C15 used in this study originated from Eastern Texas and were cultivated for 14 years in Pine Tree, AR. P. deltoides clones S13C20 and S7C15 had specific gravities of 0.48 and 0.40, respectively. Bark and wood were examined separately. As expected, hot water pretreatments, in the tested temperature range, resulted in very little direct xylose recovery. However, the 140°C dilute acid pretreatment of the lower specific gravity clone, S7C15, wood yielded the highest average xylose recovery of 56%. This condition also yielded the highest concentration of furfural, 9 mg/g sample, which can be inhibitory to the fermentation step. The highest xylose recovery from bark samples, 31%, was obtained with clone S7C15, using the 160°C dilute acid pretreatment for 60 min.

  19. The transcriptome of Populus in elevated CO2 reveals increased anthocyanin biosynthesis during delayed autumnal senescence

    Energy Technology Data Exchange (ETDEWEB)

    Tallis, M.J.; Rogers, A.; Lin, Y.; Zhang, J.; Street, N. R.; Miglietta, F.; Karnosky, D. F.; Angelis, P. D.; Calfapietra, C.; Taylor, G.

    2010-03-01

    The delay in autumnal senescence that has occurred in recent decades has been linked to rising temperatures. Here, we suggest that increasing atmospheric CO{sub 2} may partly account for delayed autumnal senescence and for the first time, through transcriptome analysis, identify gene expression changes associated with this delay. Using a plantation of Populus x euramericana grown in elevated [CO{sub 2}] (e[CO{sub 2}]) with free-air CO{sub 2} enrichment (FACE) technology, we investigated the molecular and biochemical basis of this response. A Populus cDNA microarray was used to identify genes representing multiple biochemical pathways influenced by e[CO{sub 2}] during senescence. Gene expression changes were confirmed through real-time quantitative PCR, and leaf biochemical assays. Pathways for secondary metabolism and glycolysis were significantly up-regulated by e[CO{sub 2}] during senescence, in particular, those related to anthocyanin biosynthesis. Expressed sequence tags (ESTs) representing the two most significantly up-regulated transcripts in e[CO{sub 2}], LDOX (leucoanthocyanidin dioxgenase) and DFR (dihydroflavonol reductase), gave (e[CO{sub 2}]/ambient CO{sub 2} (a[CO{sub 2}])) expression ratios of 39.6 and 19.3, respectively. We showed that in e[CO{sub 2}] there was increased autumnal leaf sugar accumulation and up-regulation of genes determining anthocyanin biosynthesis which, we propose, prolongs leaf longevity during natural autumnal senescence.

  20. Fractionation of alkali-solubilized hemicelluloses from delignified Populus gansuensis: structure and properties.

    Science.gov (United States)

    Peng, Feng; Ren, Jun-Li; Xu, Feng; Bian, Jing; Peng, Pai; Sun, Run-Cang

    2010-05-12

    The dewaxed cell walls of Populus gansuensis were delignified with NaClO(2) and then sequentially extracted with 0.25, 0.5, and 1.0 M KOH under a solid to liquid ratio of 1: 25 (g mL(-1)) at 25 degrees C for 10 h. The successive treatments together resulted in the dissolution of 83.7% of original hemicelluloses. The solubilized hemicellulosic fractions were further fractionated into six hemicellulosic subfractions by an iodine-complex precipitation technique. Their chemical and physical characteristics were determined by HPAEC, GPC, FT-IR, and (1)H and (13)C NMR spectroscopy. Neutral sugar composition and molecular weight analysis showed that, for each extract, the hemicellulosic subfractions that precipitated with aqueous potassium iodide-iodine had lower overall uronic acid/xylose (Uro/Xyl) ratios and higher molecular weights (M(w)) than those remaining in the solution. FT-IR, (1)H, and (13)C NMR spectroscopy analysis indicated that the alkali-soluble hemicelluloses of Populus gansuensis had a structure composed of the (1 --> 4)-linked beta-D-xylopyranosyl backbone with 4-O-methyl-alpha-D-glucuronic acid attached to O-2 of the xylose residues.

  1. Gene Structures, Classification, and Expression Models of the DREB Transcription Factor Subfamily in Populus trichocarpa

    Directory of Open Access Journals (Sweden)

    Yunlin Chen

    2013-01-01

    Full Text Available We identified 75 dehydration-responsive element-binding (DREB protein genes in Populus trichocarpa. We analyzed gene structures, phylogenies, domain duplications, genome localizations, and expression profiles. The phylogenic construction suggests that the PtrDREB gene subfamily can be classified broadly into six subtypes (DREB A-1 to A-6 in Populus. The chromosomal localizations of the PtrDREB genes indicated 18 segmental duplication events involving 36 genes and six redundant PtrDREB genes were involved in tandem duplication events. There were fewer introns in the PtrDREB subfamily. The motif composition of PtrDREB was highly conserved in the same subtype. We investigated expression profiles of this gene subfamily from different tissues and/or developmental stages. Sixteen genes present in the digital expression analysis had high levels of transcript accumulation. The microarray results suggest that 18 genes were upregulated. We further examined the stress responsiveness of 15 genes by qRT-PCR. A digital northern analysis showed that the PtrDREB17, 18, and 32 genes were highly induced in leaves under cold stress, and the same expression trends were shown by qRT-PCR. Taken together, these observations may lay the foundation for future functional analyses to unravel the biological roles of Populus’ DREB genes.

  2. An Elite Variety of Populus deltoides‘Beiyang’%杨树良种‘北杨’

    Institute of Scientific and Technical Information of China (English)

    曹国玉; 李继祥; 买买提库尔班·阿力; 李开花; 胡建军

    2016-01-01

    The‘Beiyang’,male clone and intraspecific hybrid of Populus deltoides hybrid,was selected from the progeny of Populus deltoides‘Nankang’× P. deltoides‘D175’by the way of artificial control cross pollination. Average DBH,height and volume of nine-year-old‘Beiyang’were 21. 3 cm,20. 4 m and 0. 250 m3 ,which were 49. 9% greater than the control‘2025’. The elite variety has the fine characteristics such as straight trunk,middle crown,fast-growing, strong resistance to Anoplophora glaberipennis and soil barren tolerance.%‘北杨’是通过人工控制授粉选育而成,雄株,为美洲黑杨种内杂种,其母本为南抗杨,父本为‘D175’。9年生平均胸径21.3 cm,平均树高20.4 m,单株材积0.250 m3,比对照‘中林2025杨’材积生长量提高49.9%。树冠长卵形,干形通直,冠幅中等,早期速生,抗光肩星天牛,耐瘠薄。

  3. Salt stress induces the formation of a novel type of 'pressure wood' in two Populus species.

    Science.gov (United States)

    Janz, Dennis; Lautner, Silke; Wildhagen, Henning; Behnke, Katja; Schnitzler, Jörg-Peter; Rennenberg, Heinz; Fromm, Jörg; Polle, Andrea

    2012-04-01

    • Salinity causes osmotic stress and limits biomass production of plants. The goal of this study was to investigate mechanisms underlying hydraulic adaptation to salinity. • Anatomical, ecophysiological and transcriptional responses to salinity were investigated in the xylem of a salt-sensitive (Populus × canescens) and a salt-tolerant species (Populus euphratica). • Moderate salt stress, which suppressed but did not abolish photosynthesis and radial growth in P. × canescens, resulted in hydraulic adaptation by increased vessel frequencies and decreased vessel lumina. Transcript abundances of a suite of genes (FLA, COB-like, BAM, XET, etc.) previously shown to be activated during tension wood formation, were collectively suppressed in developing xylem, whereas those for stress and defense-related genes increased. A subset of cell wall-related genes was also suppressed in salt-exposed P. euphratica, although this species largely excluded sodium and showed no anatomical alterations. Salt exposure influenced cell wall composition involving increases in the lignin : carbohydrate ratio in both species. • In conclusion, hydraulic stress adaptation involves cell wall modifications reciprocal to tension wood formation that result in the formation of a novel type of reaction wood in upright stems named 'pressure wood'. Our data suggest that transcriptional co-regulation of a core set of genes determines reaction wood composition.

  4. Assessing the potential of short rotation coppice (SRC) for cleanup of radionuclide-contaminated sites.

    Science.gov (United States)

    Dutton, M V; Humphreys, P N

    2005-01-01

    A small-scale greenhouse investigation was undertaken using Goat willow (Salix caprea) and aspen (Populus tremula) to evaluate the potential of short rotation coppice for remediation of 137Cs- and 90Sr-contaminated sites. Results showed that both species were able to accumulate these radionuclides from a representative disposal soil (aged) and a spiked soil S. caprea accumulating greater levels of 137Cs than P. tremula, with no difference between species for 90Sr accumulation. For each radionuclide, the distribution in both species was similar, with 137Cs accumulation greatest in the roots, whereas 90Sr accumulation was greatest in the leaves. It was also evident that the soil-to-plant transfer factor (Tf) values for 90Sr were greater than for 137Cs, agreeing with differences in the reported bioavailailablity of these radionuclides in soil Based on the Tf values for S. caprea (conservative), estimated remediation times were 92 and 56 yr, for 137Cs and 90Sr, respectively. It is suggested that the selection of Salix species grown in a system of SRC provides a significant opportunity for removal of both 137Cs and 90Sr, primarily due to its higher biomass production. However, for 137Cs phytoremediation investigations into the appropriate use of soil amendments for increasing bioavailability are required.

  5. Multi-Objective Optimization of Dividing Wall Columns with Aspen Plus and NSGA-Ⅱ%基于Aspen Plus和NSGA-II的隔壁塔多目标优化研究

    Institute of Scientific and Technical Information of China (English)

    李军; 王纯正; 马占华; 孙兰义

    2015-01-01

    以年总操作费用(TAC)和再沸器负荷为目标,提出了基于遗传算法 NSGA-Ⅱ的优化方法,并将该方法应用于BTX分离隔壁塔的优化设计。首先应用Aspen Plus软件建立了BTX分离工艺的隔壁塔Radfrac两塔模型,并在Matlab平台上,通过MAP接口工具箱实现Matlab对Aspen Plus的操作与控制,同时Matlab调用NSGA-Ⅱ进行优化,完成种群大小为600、遗传代数为28的模拟过程,得到了10组Pareto解。研究表明,对于Pareto解分布,气相分配量βg、液相分配量βL、侧线抽出位置NS和液相分配位置NL基本不变,进料位置NF、预分馏塔板Nj和主塔板数Ni存在一定的线性关系。%An optimized method was used to evaluate the performance of dividing wall columns in BTX separation with multi-objective genetic algorithm to minimize theTAC andHeat duty. A two-column Radfrac model was established for the separation of BTX by Aspen Plus software. Matlab can operate and control Aspen Plus using MAP and it can use NSGA-II for optimization. Ten Pareto fronts were obtained with population of six hundred and generation of twenty-eight. The results show that interconnection vapor flowβg , interconnection liquid flowβL, stage of side productNS and stage of interconnection liquidNL are relatively stable on the base of distribution of Pareto front. However, there is a linear relationship between the number of the stages of prefractionator and that of the main column. The feed stage has a linear relationship with the prefractionator stage numbers.

  6. ¿Son las herramientas recomendadas por la ASPEN y la ESPEN equiparables en la valoración del estado nutricional? Are the tools recommended by ASPEN and ESPEN comparable for assessing the nutritional status?

    OpenAIRE

    M.ª A. Valero; L. Díez; N. El Kadaoui; Jiménez, A. E.; H. Rodríguez; M. León

    2005-01-01

    Introducción: No existe un método de valoración nutricional universalmente aceptado. Los expertos de ASPEN (2002) sugieren utilizar la valoración subjetiva global (VSG), mientras que los de ESPEN (2002) recomiendan el sistema NRS-2002. Objetivos y ámbito: Este estudio transversal tiene como objetivos: 1) conocer la prevalencia de malnutrición al ingreso hospitalario en un hospital terciario y 2) conocer el grado de asociación entre dos herramientas utilizadas para valorar el estado de nutrici...

  7. Study on vent washing and waste-heat recovery of DAP plant based on ASPEN PLUS%基于ASPEN PLUS的磷酸二铵装置尾气洗涤及余热回收研究

    Institute of Scientific and Technical Information of China (English)

    田静; 莫春萍; 王万林; 张秀芳; 郑建国

    2014-01-01

    利用脱盐水间接冷凝尾气中的水蒸气以减少白雾的排放和回收尾气的低温位余热,同时使用ASPEN PLUS软件对尾气洗涤塔及余热回收过程进行模拟.结果表明,该软件模拟结果与现场测量参数较为吻合,可用于指导生产,并为装置改造提供依据.

  8. Optimization of Energy Consumption in Chemical Industry with Aspen Plus and Pinch Technology System%用Aspen Plus和夹点技术系统调优化工用能

    Institute of Scientific and Technical Information of China (English)

    白玫

    2009-01-01

    针对我国的炼化工业越来越注重装置的基础设计和优化改造这一现状,提出了利用夹点技术和Aspen Plus模拟来实现化工过程全局用能优化的方法,该方法可以进一步节省蒸汽、燃料和循环水,并通过实例证明了此法的有效性.

  9. Research Progress on the Salt-tolerance of Populus spp.%杨树耐盐性研究进展

    Institute of Scientific and Technical Information of China (English)

    陈必胜; 汪晓沙; 黄梅; 朱继军; 林登贵; 李梅玲; 李萍; 曾丽

    2012-01-01

    杨树生长迅速、生物产量高,是一种世界性的造林树种,一些杨树具有较强的耐盐性,对盐碱化土地的利用和开发具有重要价值.对盐胁迫下杨树的植物学特征、生理生化指标变化、耐盐分子机制和遗传改良策略进行了综述,并对深入地解析杨树耐盐分子机制应采取策略和在生产中应用前景进行了讨论,以期为筛选和培育耐盐杨树品种提供借鉴和参考.%Populus spp. is a world-wide tree species for forestation with rapid growth and higher biomass. Due to stronger salt-tolerance of some Populus spp. varieties, they may be used to exploit the potential value of the salinized land. Several properties of Populus spp. under salt stress were reviewed, including the botanical features, physiological and biochemical indexes, and molecular response; furthermore, the molecular mechanism and genetic improvement strategies for poplar salt-tolerance were outlined and discussed, so as to provide reference for screening and developing Populus spp. variety with slat tolerance.

  10. Biomass traits and candidate genes for bioenergy revealed through association genetics in coppiced European Populus nigra (L.)

    NARCIS (Netherlands)

    Allwright, Mike Robert; Payne, Adrienne; Emiliani, Giovanni; Milner, Suzanne; Viger, Maud; Rouse, Franchesca; Keurentjes, Joost J.B.; Bérard, Aurélie; Wildhagen, Henning; Faivre-Rampant, Patricia; Polle, Andrea; Morgante, Michele; Taylor, Gail

    2016-01-01

    Background: Second generation (2G) bioenergy from lignocellulosic feedstocks has the potential to develop as a sustainable source of renewable energy; however, significant hurdles still remain for large-scale commercialisation. Populus is considered as a promising 2G feedstock and understanding t

  11. Analysis of a reheat gas turbine cycle with chemical recuperation using Aspen

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, S.; Kane, N`Diaye [ISITEM - Lab. d`Energetique, Nantes (France)

    1996-11-01

    Present-day high performance gas turbine based cycles use the combined cycle concept in which the heat in the hot turbine exhaust stream is used to raise steam which can be used to generate electricity using a steam turbine. Recent attention has focused in particular on the chemical heat recovery concept.The potential benefits of such cycles include high conversion efficiency, ultra-low NO{sub x} emission levels (less than 1 ppm) and high power density per unit of land. The low thermal NO{sub X} emissions result from the presence of hydrogen in the reformed fuel gas, which enables combustion at lower flame temperatures. Thus, a CRGT (Chemically Recuperated Gas Turbine) cycle can meet the strictest NO{sub x} limits in operation today without the need for selective catalytic reduction. Such environmental characteristics are the primary reason fuelling current interest in CRGT cycles. For design reasons, reheat combustors cannot be easily adapted to stationary gas turbines, and until recently the CRGT cycle seemed to be limited to aeroderivative gas turbine applications. However, ABB recently unveiled its new GT26 series stationary gas turbines using staged expansion with reheat combustion, allowing high thermal efficiencies with relatively low turbine inlet temperatures. This type of turbine appears particularly well-suited for chemical heat recovery. In this paper, we present a CRGT cycle based on a reheat gas turbine with key design features similar to those of ABB`s GT26 machine. The cycle analysis is performed using ASPEN+ process simulation software. The report includes a detailed first and second law analysis of the cycle. The results confirm that the energy conversion efficiencies of CRGT cycles cannot rival with the efficiencies achieved by state-of-the-art combined cycles. 12 refs, 3 figs, 5 tabs

  12. Pyrolysis of waste tires: A modeling and parameter estimation study using Aspen Plus(®).

    Science.gov (United States)

    Ismail, Hamza Y; Abbas, Ali; Azizi, Fouad; Zeaiter, Joseph

    2017-02-01

    This paper presents a simulation flowsheet model of a waste tire pyrolysis process with feed capacity of 150kg/h. A kinetic rate-based reaction model is formulated in a form implementable in the simulation package Aspen Plus, giving the flowsheet model the capability to predict more than 110 tire pyrolysis products as reported in experiments by Laresgoiti et al. (2004) and Williams (2013) for the oil and gas products respectively. The simulation model is successfully validated in two stages: firstly against experimental data from Olazar et al. (2008) by comparing the mass fractions for the oil products (gas, liquids (non-aromatics), aromatics, and tar) at temperatures of 425, 500, 550 and 610°C, and secondly against experimental results of main hydrocarbon products (C7 to C15) obtained by Laresgoiti et al. (2004) at temperatures of 400, 500, 600, and 700°C. The model was then used to analyze the effect of pyrolysis process temperature and showed that increased temperatures led to chain fractions from C10 and higher to decrease while smaller chains increased; this is attributed to the extensive cracking of the larger hydrocarbon chains at higher temperatures. The utility of the flowsheet model was highlighted through an energy analysis that targeted power efficiency of the process determined through production profiles of gasoline and diesel at various temperatures. This shows, through the summation of the net power gain from the plant for gasoline plus diesel that the maximum net power lies at the lower temperatures corresponding to minimum production of gasoline and maximum production of diesel. This simulation model can thus serve as a robust tool to respond to market conditions that dictate fuel demand and prices while at the same time identifying optimum process conditions (e.g. temperature) driven by process economics.

  13. Simulation of integrated pollutant removal (IPR) water-treatment system using ASPEN Plus

    Energy Technology Data Exchange (ETDEWEB)

    Harendra, Sivaram; Oryshcyhn, Danylo [U.S. DOE/NETL; Ochs, Thomas [U.S. DOE/NETL; Gerdemann, Stephen; Clark, John

    2013-01-01

    Capturing CO2 from fossil fuel combustion provides an opportunity for tapping a significant water source which can be used as service water for a capture-ready power plant and its peripherals. Researchers at the National Energy Technology Laboratory (NETL) have patented a process—Integrated Pollutant Removal (IPR®)—that uses off-the-shelf technology to produce a sequestration ready CO2 stream from an oxy-combustion power plant. Water condensed from oxy-combustion flue gas via the IPR system has been analyzed for composition and an approach for its treatment—for in-process reuse and for release—has been outlined. A computer simulation model in ASPEN Plus has been developed to simulate water treatment of flue gas derived wastewater from IPR systems. At the field installation, water condensed in the IPR process contains fly ash particles, sodium (largely from spray-tower buffering) and sulfur species as well as heavy metals, cations, and anions. An IPR wastewater treatment system was modeled using unit operations such as equalization, coagulation and flocculation, reverse osmosis, lime softening, crystallization, and pH correction. According to the model results, 70% (by mass) of the inlet stream can be treated as pure water, the other 20% yields as saleable products such as gypsum (CaSO4) and salt (NaCl) and the remaining portion is the waste. More than 99% of fly ash particles are removed in the coagulation and flocculation unit and these solids can be used as filler materials in various applications with further treatment. Results discussed relate to a slipstream IPR installation and are verified experimentally in the coagulation/flocculation step.

  14. Estimation of Power Production Potential from Natural Gas Pressure Reduction Stations in Pakistan Using ASPEN HYSYS

    Directory of Open Access Journals (Sweden)

    Imran Nazir Unar

    2015-07-01

    Full Text Available Pakistan is a gas rich but power poor country. It consumes approximately 1, 559 Billion cubic feet of natural gas annually. Gas is transported around the country in a system of pressurized transmission pipelines under a pressure range of 600-1000 psig exclusively operated by two state owned companies i.e. SNGPL (Sui Northern Gas Pipelines Limited and SSGCL (Sui Southern Gas Company Limited. The gas is distributed by reducing from the transmission pressure into distribution pressure up to maximum level of 150 psig at the city gate stations normally called SMS (Sales Metering Station. As a normal practice gas pressure reduction at those SMSs is accomplished in pressure regulators (PCVs or in throttle valves where isenthalpic expansion takes place without producing any energy. Pressure potential of natural gas is an untapped energy resource which is currently wasted by its throttling. This pressure reduction at SMS (pressure drop through SMS may also be achieved by expansion of natural gas in TE, which converts its pressure into the mechanical energy, which can be transmitted any loading device for example electric generator. The aim of present paper is to explore the expected power production potential of various Sales Metering Stations of SSGCL company in Pakistan. The model of sales metering station was developed in a standard flow sheeting software Aspen HYSYS®7.1 to calculate power and study other parameters when an expansion turbine is used instead of throttling valves. It was observed from the simulation results that a significant power (more than 140 KW can be produced at pressure reducing stations of SSGC network with gas flows more than 2.2 MMSCFD and pressure ration more than 1.3.

  15. Aspen软件在大型聚乙烯装置上的应用%Application of Aspen software in large-scale polyethylene plant

    Institute of Scientific and Technical Information of China (English)

    王文庆; 李延辉

    2004-01-01

    以线型低密度聚乙烯装置产品牌号切换时的露点计算为例,对采用AspenTech公司的Aspen P1us、InfoPlus.21软件的应用进行了研究与分析.使用Aspen软件可以实现露点等物性数据的实时计算,为安全、稳定地进行产品牌号切换提供准确的依据;而且,可以使用Visual Basic语言将Aspen Plus的输入数据和模拟结果与其他应用程序相连接,实现全自动的数据采集与计算.

  16. ASPEN PLUS软件模拟干气、液态烃脱硫和再生系统工艺流程

    Institute of Scientific and Technical Information of China (English)

    黄崇平

    2001-01-01

    Aspen Plus流程模拟软件是石油化工装置工艺设计中的重要工具。用Aspen Plus流程模拟软件对我厂干气,液态烃脱硫和再生系统的工艺流程进行模拟计算,计算结果与装置的实际运行情况基本吻合,说明AspenPlus模拟计算采用的热力学方程和建立的模拟流程有较高的可信度。

  17. Soil Organic Carbon Storage and Stability in the Aspen-Conifer Ecotone in Montane Forests in Utah, USA

    Directory of Open Access Journals (Sweden)

    Mercedes Román Dobarco

    2014-04-01

    Full Text Available To assess the potential impact of conifer encroachment on soil organic carbon (SOC dynamics and storage in montane aspen-conifer forests from the interior western US, we sampled mineral soils (0–15 cm across the aspen-conifer ecotones in southern and northern Utah and quantified total SOC stocks, stable SOC (i.e., mineral-associated SOC (MoM, labile SOC (i.e., light fraction (LF, decomposable (CO2 release during long-term aerobic incubations and soluble SOC (hot water extractable organic carbon (HWEOC. Total SOC storage (47.0 ± 16.5 Mg C ha−1 and labile SOC as LF (14.0 ± 7.10 Mg C ha−1, SOC decomposability (cumulative released CO2-C of 5.6 ± 3.8 g C g−1 soil or HWEOC (0.6 ± 0.6 mg C g−1 soil did not differ substantially with vegetation type, although a slight increase in HWEOC was observed with increasing conifer in the overstory. There were statistically significant differences (p = 0.035 in stable MoM storage, which was higher under aspen (31.2 ± 15.1 Mg C ha−1 than under conifer (22.8 ± 9.0 Mg C ha−1, with intermediate values under mixed (25.7 ± 8.8 Mg C ha−1. Texture had the greatest impact on SOC distribution among labile and stable fractions, with increasing stabilization in MoM and decreasing bio-availability of SOC with increasing silt + clay content. Only at lower silt + clay contents (40%–70% could we discern the influence of vegetation on MoM content. This highlights the importance of chemical protection mechanisms for long-term C sequestration.

  18. Interface between MATLAB and Aspen Plus Based on COM Technology and its Advanced Application%基于COM技术的MATLAB与AsPen Plus接口及高级应用

    Institute of Scientific and Technical Information of China (English)

    耿大钊; 陈曦; 邵之江; 钱积新

    2006-01-01

    基于COM技术研制开发了MATLAB和Aspen Plus的接口工具箱MAP,实现了在MATLAB环境下对Aspen Plus中数据进行读写操作,并控制模拟的运行.MAP接口将MATLAB计算能力和Aspen Plus的模拟能力结合在一起,扩展了Aspen Plus的高级应用.通过精馏塔进料软测量的示例,阐述了如何通过MAP接口来调用自主开发的禁忌搜索优化算法,解决由于Aspen Plus中的优化算法的局限性所无法实现的模拟与优化问题.

  19. ASPEN PLUS对混合二甲苯分离工艺的分析研究

    Institute of Scientific and Technical Information of China (English)

    刘春法; 孙剑; 阮栋

    2005-01-01

    C8芳烃(混合二甲苯)由于组分来源的不同,组分较多,组分间沸点差很小,使C8芳烃分离可供选择的流程很多:化工分公司应用ASPEN PLUS软件,研究了超精馏工艺分离混合二甲苯的可行性。

  20. Aspen Plus模拟醋酸正丁酯反应精馏工艺过程

    Institute of Scientific and Technical Information of China (English)

    王丽; 昊世逵; 吴剑锋; 周博煊; 王雨

    2013-01-01

    利用Aspen Plus对醋酸正丁酯的合成工艺流程进行了模拟计算。选用反应精馏技术,用强酸性阳离子交换树脂取代硫酸,在反应精馏塔中一次完成反应和分离,取代原有的分步流程,可连续生产出99.9%的高纯度醋酸正丁酯。

  1. Aspen simulation of chlorine and hydrogen chloride absorption system%基于Aspen的氯气、氯化氢气体吸收系统的模拟

    Institute of Scientific and Technical Information of China (English)

    王银亮; 刘军

    2016-01-01

    采用Aspen Plus对某项目氯气、氯化氢气体吸收系统进行了稳态模拟,并对吸收剂的用量进行了优化;在得到基础数据的基础上,利用Aspen HYSYS对该吸收系统进行了动态模拟,明确了部分参数的变化对吸收率产生的影响,对项目开车及员工培训方案的制定具有重要的参考作用.

  2. Comparative analysis of the effect of pretreating aspen wood with aqueous and aqueous-organic solutions of sulfuric and nitric acid on its reactivity during enzymatic hydrolysis

    DEFF Research Database (Denmark)

    Dotsenko, Gleb; Osipov, D. O.; Zorov, I. N.;

    2016-01-01

    The effect of aspen wood pretreatment methods with the use of both aqueous solutions of sulfuric and nitric acids and aqueous-organic solutions (ethanol, butanol) of sulfuric acid (organosolv) on the limiting degree of conversion of this type of raw material into simple sugars during enzymatic...... of ground wood by 300–400%, compared to the initial raw material. Pretreatment with a 4.8% aqueous solution of nitric acid (125°C, 1.8 MPa, 10 min) is shown to be most effective, as it increases the reactivity of the ground aspen wood by more than 500%....

  3. 基于Aspen Plus的稀氨水吹脱工艺流程模拟%Simulation for Stripping Process flow of Dilute Ammonia Liquor Based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    任苏孟; 陈洁; 宣爱国; 李志刚

    2014-01-01

    为了降低合成氨工艺中稀氨水的排放浓度,使用Aspen Plus 软件对氨水吹脱过程进行模拟计算,在满足塔底氨含量小于0.5%的要求下,得出吹脱塔适宜的操作参数:进料空气流量为500 kg/h,进料氨水温度为60℃,理论塔板为6块,选用50 mm钢制矩鞍环填料,塔径为1.4 m。%In order to decrease the concentration of diluted ammonia water emissions in synthetic ammonia process , the ammonia water stripping process was simulated based on Aspen Plus software.Under satisfying the condition that ammonia content in the tower bottom was less than 0.5%, the suitable operation parameters were obtained for the air stripping tower .The feeding temperature of ammonia water was 60℃, number of theoretical tower plates was 6, the feeding air flow was 500 kg/h, and the diameter of the stripping tower was 1.4 m with φ50 steel INTX packing selected.

  4. Simulation and Analysis of Methanol Distillation based on Aspen Plus User Model%基于Aspen Plus用户模型的甲醇精馏模拟与分析

    Institute of Scientific and Technical Information of China (English)

    朱建宁; 陆文斌

    2012-01-01

    采用模拟软件Aspen Plus对某厂大型煤化工甲醇四塔精馏过程进行稳态模拟计算和分析,结果表明,应用物性方法 UNIFAC-DMD能有效模拟汽液平衡数据,模拟结果与工厂采集数据吻合良好。进行了常压塔侧线抽提位置分析、回流比对产品各组分浓度影响及精馏塔水力学分析等研究,提供了可行的精馏操作方案。%Using Aspen Plus,steady-state simulation and analysis were carried out on the four-column methanol distillation process in a large-scale coal chemical industry plant.It turned out that the vapor-liquid equilibrium data could effectively simulated by UNIFAC-DMD,and the simulation results were in good agreement with the practical industrial production data.Moreover,some operation conditions such as the location of side extraction,influences of reflux ratio on product components concentration and distillation column hydraulics were analyzed,and a feasible distillation scheme was put forward.

  5. 基于Aspen Plus的超大规模甲醇合成工艺模型%Simulation of large scale methanol synthesis process based on Aspen Plus

    Institute of Scientific and Technical Information of China (English)

    何一夫

    2013-01-01

    The large scale methanol synthesis process model is proposed and simulated by ASPEN PLUS software. The crude methanol composition, the reactor outlet composition, the carbon efficiency and the recycle ratio are obtained, which presents the recycle ratio has great influence on the methanol mole flow, carbon efficiency, recycle gas compressor power and synthesis gas compressor power. The model can simulate and predict the large scale methanol synthesis process for process comparison and optimization design.%利用Aspen Plus对超大规模甲醇合成工艺进行了全流程模拟.模型模拟得到了粗甲醇的成分、反应器出口组成、碳效率、循环比,揭示了循环比对粗甲醇中甲醇摩尔流速、整个反应碳效率、循环气压缩机功率、合成气压缩机功率的影响.通过该模型能够为工艺方案比选、优化设计提供模拟和预测.

  6. 化工流程模拟软件Aspen Plus在湿法冶金学教学中的应用%Application of Aspen Plus in the Teaching Process of Hydrometallurgy

    Institute of Scientific and Technical Information of China (English)

    蓝德均

    2011-01-01

    The relationship between the chemical process simulation software,ASPEN Plus and the teaching process of Hydrometallurgy was discussed in detail.Introduction of ASPEN into the teaching process of Hydrometallurgy was practical completely,which was contributed to impart knowledge into students for improving teaching effect in the process of theoretical teaching,and to enhance the practice of Hydrometallurgy for the last goal of the course,and to give students the convenient fast simple pre-training of the job before working.%详细讨论了化工流程模拟软件ASPEN与湿法冶金学教学的关系。ASPEN软件的引入对于湿法冶金教学过程是完全可行的。这即有利于理论教学过程中对知识的灌输,改善教学效果,也有利于增强课程的实践环节,强化课程教学的最终目的,更可以使学生得到方便、快速、简单地就业前的岗位预训练。

  7. Simulation analysis with Aspen plus for hydrogen production by steam reforming of natural gas%天然气水蒸汽转化制氢的Aspen plus模拟分析

    Institute of Scientific and Technical Information of China (English)

    姜薇; 马瑞; 赵峰; 张桂林

    2013-01-01

    The chemical software Aspen plus was used to simulate the steam reforming and water-gas shift reaction in the process of hydrogen production from natural gas. The simulation results were very consistent with the actual data, which indicated that the built process simulation model and the chosen equations for thermodynamic properties were right. Through the sensitivity analysis of the operating variables, the impacts of the steam to carbon ratio, temperature and pressure on the the reforming and water-gas shift processes were investigated.%应用化工模拟软件Aspen plus对天然气水蒸汽转化制氢生产工艺中转化及中变反应过程进行模拟.通过模拟结果与实际生产数据比较,两者非常吻合,说明所建流程模拟模型及热力学物性方程选择正确.对转化及中变过程的操作变量进行了灵敏度分析,得到了水碳比、温度、压力等重要操作参数对工艺的影响.

  8. A 34K SNP genotyping array for Populus trichocarpa: design, application to the study of natural populations and transferability to other Populus species.

    Science.gov (United States)

    Geraldes, A; Difazio, S P; Slavov, G T; Ranjan, P; Muchero, W; Hannemann, J; Gunter, L E; Wymore, A M; Grassa, C J; Farzaneh, N; Porth, I; McKown, A D; Skyba, O; Li, E; Fujita, M; Klápště, J; Martin, J; Schackwitz, W; Pennacchio, C; Rokhsar, D; Friedmann, M C; Wasteneys, G O; Guy, R D; El-Kassaby, Y A; Mansfield, S D; Cronk, Q C B; Ehlting, J; Douglas, C J; Tuskan, G A

    2013-03-01

    Genetic mapping of quantitative traits requires genotypic data for large numbers of markers in many individuals. For such studies, the use of large single nucleotide polymorphism (SNP) genotyping arrays still offers the most cost-effective solution. Herein we report on the design and performance of a SNP genotyping array for Populus trichocarpa (black cottonwood). This genotyping array was designed with SNPs pre-ascertained in 34 wild accessions covering most of the species latitudinal range. We adopted a candidate gene approach to the array design that resulted in the selection of 34 131 SNPs, the majority of which are located in, or within 2 kb of, 3543 candidate genes. A subset of the SNPs on the array (539) was selected based on patterns of variation among the SNP discovery accessions. We show that more than 95% of the loci produce high quality genotypes and that the genotyping error rate for these is likely below 2%. We demonstrate that even among small numbers of samples (n = 10) from local populations over 84% of loci are polymorphic. We also tested the applicability of the array to other species in the genus and found that the number of polymorphic loci decreases rapidly with genetic distance, with the largest numbers detected in other species in section Tacamahaca. Finally, we provide evidence for the utility of the array to address evolutionary questions such as intraspecific studies of genetic differentiation, species assignment and the detection of natural hybrids.

  9. On the irrigation requirements of cottonwood (Populus fremontii and Populus deltoides var. wislizenii) and willow (Salix gooddingii) grown in a desert environment

    Science.gov (United States)

    Hartwell, S.; Morino, K.; Nagler, P.L.; Glenn, E.P.

    2010-01-01

    Native tree plots have been established in river irrigation districts in the western U.S. to provide habitat for threatened and endangered birds. Information is needed on the effective irrigation requirements of the target species. Cottonwood (Populus spp.) and willow (Salix gooddingii) trees were grown for seven years in an outdoor plot in a desert environment in Tucson, Arizona. Plants were allowed to achieve a nearly complete canopy cover over the first four years, then were subjected to three daily summer irrigation schedules of 6.20??mm??d-1; 8.26??mm??d-1 and 15.7??mm??d-1. The lowest irrigation rate was sufficient to maintain growth and high leaf area index for cottonwoods over three years, while willows suffered considerable die-back on this rate in years six and seven. These irrigation rates were applied April 15-September 15, but only 0.88??mm??d-1 was applied during the dormant period of the year. Expressed as a fraction of reference crop evapotranspiration (ETo), recommended annual water applications plus precipitation (and including some deep drainage) were 0.83 ETo for cottonwood and 1.01 ETo for willow. Current practices tend to over-irrigate restoration plots, and this study can provide guidelines for more efficient water use. ?? 2010 Elsevier Ltd.

  10. Design, fabrication, operation and Aspen simulation of oil shale pyrolysis and biomass gasification process using a moving bed downdraft reactor

    Science.gov (United States)

    Golpour, Hassan

    Energy is the major facilitator of the modern life. Every developed and developing economy requires access to advanced sources of energy to support its growth and prosperity. Declining worldwide crude oil reserves and increasing energy needs has focused attention on developing existing unconventional fossil fuels like oil shale and renewable resources such as biomass. Sustainable, renewable and reliable resources of domestically produced biomass comparing to wind and solar energy is a sensible motivation to establish a small-scale power plant using biomass as feed to supply electricity demand and heat for rural development. The work in Paper I focuses on the possibility of water pollution from spent oil shale which should be studied before any significant commercial production is attempted. In Paper II, the proposed Aspen models for oil shale pyrolysis is to identify the key process parameters for the reactor and optimize the rate of production of syncrude from oil shale. The work in Paper III focuses on (1) Design and operation of a vertical downdraft reactor, (2) Establishing an optimum operating methodology and parameters to maximize syngas production through process testing. Finally in Paper IV, a proposed Aspen model for biomass gasification simulates a real biomass gasification system discussed in Paper III.

  11. Comparison of energy penalty in post-combustion and pre-combustion calcium looping systems using aspen plus

    Directory of Open Access Journals (Sweden)

    Wei Dai, Subhodeep Banerjee, Ramesh K. Agarwal

    2017-01-01

    Full Text Available Calcium looping (CaL is a recent technology that utilizes calcium oxide (CaO and the carbonation-calcination equilibrium reactions to capture carbon dioxide (CO2 from the flue stream of fossil fueled power plants. In this paper, system level simulations are developed in Aspen Plus to calculate the energy penalty of introducing calcium looping in a coal fired power plant. Both post-combustion and pre-combustion capture scenarios are investigated. The relationship between various flow ratios, the conversion rate of CaO, and the carbon capture efficiency is used to validate the Aspen Plus model for the calcium looping process; it agrees well with the experimental data and simulation results available in the literature. The simulation shows an increasing marginal energy penalty associated with an increase in the carbon capture efficiency, which limits the maximum carbon capture efficiency in real-world applications of calcium looping to between 95% and 98% before the energy penalty becomes too large.

  12. Model of leaf energy distribution and its experimental validation of Populus tomentosa Carr

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen-jie; WANG Min; SHEN Ying-bai; ZHANG Zhi-yi

    2008-01-01

    Leaf temperature of a plant is the result of heat transfer between the plant and its environment. There are many factors that can affect leaf temperature, such as the solar radiation energy, environmental temperature, wind velocity, evaporation on the leaf surface, photosynthesis, respiration and so on, which have different effects on the temperature of leaves. In first instance, we analyzed the heat transfer on leaves of Populus tomentosa Cart. theoretically and constructed a model of energy distribution. We then validated the model by analyzing seven different kinds of one-year-old P. tomentosa leaves experimentally. The result shows that solar radiation is the main energy input and the dominant ways of thermal diffusion are heat transfer between the upper and lower leaf surfaces and evaporation from the leaf surface.

  13. Stomata morphological traits in two different genotypes of Populus nigra L.

    Directory of Open Access Journals (Sweden)

    Russo G

    2015-08-01

    Full Text Available Populus nigra L. (black poplar possesses amphistomatic leaves, with large (giant and normal sized stomata. The role of giant stomata in leaf development, and the consequences on stomatal density in adult leaves remains elusive. This paper describes the characteristics of ordinary and giant stomata in leaves of two black poplar genotypes (58-861 with large leaves from northern Italy, and Poli with small leaves from southern Italy. Stomatal traits in both genotypes were studied using light microscopy on mature leaf adaxial and abaxial epidermal impressions. Moreover, scanning electron microscopy was applied to study giant and normal stomata in early, young, and mature leaves. Leaf abaxial surfaces in the two genotypes revealed variable sizes and patterns of stomata related to differences in intrinsic water use efficiency (Wi. These observations provided evidence of different stomatal types in mature black poplar leaves, and new information regarding the presence and potential role of giant stomata in black poplar leaves.

  14. Structural Characteristics and Eco-adaptability of Heteromorphic Leaves of Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    Li Zhao-xia; Zheng Cai-xia

    2005-01-01

    The microstructural and ultrastructural traits of three kinds of typical leaves of Populus euphratica Olive, including lanceolate, broad-ovate and dentate broad-ovate leaves, were studied by using electron microscope and optical microscope. The results showed that with the leaves changing from lanceolate shape to dentate broad-ovate shape, their structure obviously tended to be xeromorph: developed palisade tissue, undeveloped spongy tissue, thick cutin layer and sunken stomas. The amount of mitochondria tended to be increased, and the shape of chloroplasts varied from regular spindle to irregular rotundity or oval. The leaves were covered with wax without cilium, and the stomas on the upper and lower epidermis of the leaves opened unevenly. The stomas on the lower epidermis were deeper than those on the upper epidermis under the scanning electron microscope. The results implied that the structural characteristics of the diversiform-leaves of P. euphratica are related to its eco-adaptability.

  15. Significance of stigma receptivity in intergeneric cross-pollination of Salix × Populus

    Directory of Open Access Journals (Sweden)

    Elżbieta Zenkteler

    2016-09-01

    Full Text Available The pollen–stigma interaction plays an important role in reproductive process and has been continuously studied in many interspecific and intergeneric crossing experiments. The aim of this study was to investigate stigma receptivity (SR of willow in order to determine the most suitable period for its pollination with poplar pollen and improve the effectiveness of Salix × Populus crosses. Tissue samples were examined histologically using light, epifluorescent, scanning, and transmission electron microscopy. Willow SR was determined by stigma morphological traits, test of pollen germination rate, Peroxtesmo test of peroxidase and esterase activity on stigma surface as well as papilla ultrastructure at anthesis. We have ascertained that the SR duration in willow is short, lasting from 1 to 2 DA. The poplar pollen germination rate on willow stigmas on 1 DA ranged from 26.3 to 11.2%.

  16. Feeding performance of Clostera fulgurita on three clones of Populus deltoides

    Institute of Scientific and Technical Information of China (English)

    K.S.Sangha

    2011-01-01

    Poplar leaf defoliator, Closterafulgurita (Walker) larvae were reared on three Populus deltoides clones (PLI, PL5 and PL7) in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index (CI), approximate digestibility (AD), growth rate (GR), relative growth rate (RGR) and efficiency of conversion of ingested food (ECl)decreased with the increase in the age of the larvae. Efficiency of conversion of digested food (ECD) increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PLI as compared to PL5 & PL7. The values of AD, ECl and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model.

  17. The use of the white poplar (Populus alba L.) biomass as fuel

    Institute of Scientific and Technical Information of China (English)

    Tatiana Griu; Aurel Lunguleasa

    2016-01-01

    We determined the calorific value of white poplar (Populus alba L.) woody biomass to use it as fire-wood. The value of 19.133 MJ kg-1 obtained experimen-tally shows that the white poplar can be quite successfully used as firewood. Being of a lower quality in comparison with usual beech firewood, the white poplar has similar calorific value. The white poplar has a calorific density of 30.7%lower than that of current firewood. That is why the price of this firewood from white poplar is lower accord-ingly. Also, the prognosis of calorific value on the basis of the main chemical elements, being very close to the experimental value (?2.6%), indicates an appropriate value can be achieved to be used for investigation with the chemical element analysis.

  18. Population genomics of Populus trichocarpa identifies signatures of selection and adaptive trait associations

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Luke M [West Virginia University, Morgantown; Slavov, Gancho [West Virginia University, Morgantown; Rodgers-Melnick, Eli [West Virginia University, Morgantown; Martin, Joel [U.S. Department of Energy, Joint Genome Institute; Ranjan, Priya [ORNL; Muchero, Wellington [ORNL; Brunner, Amy M. [Virginia Polytechnic Institute and State University; Schackwitz, Wendy [U.S. Department of Energy, Joint Genome Institute; Gunter, Lee E [ORNL; Chen, Jay [ORNL; Tuskan, Gerald A [ORNL; Difazio, Stephen P. [West Virginia University, Morgantown

    2014-01-01

    Forest trees are dominant components of terrestrial ecosystems that have global ecological and economic importance. Despite distributions that span wide environmental gradients, many tree populations are locally adapted, and mechanisms underlying this adaptation are poorly understood. Here we use a combination of whole-genome selection scans and association analyses of 544 Populus trichocarpa trees to reveal genomic bases of adaptive variation across a wide latitudinal range. Three hundred ninety-seven genomic regions showed evidence of recent positive and/or divergent selection and enrichment for associations with adaptive traits that also displayed patterns consistent with natural selection. These regions also provide unexpected insights into the evolutionary dynamics of duplicated genes and their roles in adaptive trait variation.

  19. Interrelationships between leaf heat conductivity and tissue structures of different varieties of Populus tomentosa Carr.

    Institute of Scientific and Technical Information of China (English)

    WANG Min; ZHANG Wen-jie; XIAO Jian; ZHANG Zhi-yi; LIU Jing

    2008-01-01

    Plant heat conductivity largely depends on tissue structure. Different structures lead to different heat conductivity. As well, water transfer also plays a very important role in heat transfer in plants. We have studied leaf heat conductivity and tissue structure of 3- and 30-year-old Populus tomentosa Carr. trees using mildred thermal imaging, steady state heat conductivity surveys and paraffin section and investigated the relationship between leaf heat conductivity, tissue structure and water content of leaves. The results show that the temperature on leaf surfaces among the various varieties of trees was almost the same. Leaf heat conductivity, temperature and water content of leaves are positively correlated. The thicker the leaf tissue structures, the larger the heat resistance. That is, the tighter the cells and the smaller the interspaces, the smaller the heat conductivity, which is not conducive for heat transfer.

  20. Conversion of water consumption of a single tree and a forest stand of Populus euphratica

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-you; MENG Tong-tong; KANG Er-si

    2008-01-01

    Our study dear with the determination of sapwood sap flow of a single Populus euphratica tree by heat pulse technique and the calculation of water consumption of an entire forest stand, given the correlation between sap flow and sapwood area of P. euphratica. The relation between diameter at breast height (DBH) and sapwood area constitutes a powerful model; these variables are highly correlated. By means of an analysis of DBH in the sample plot, the distribution of the sapwood area of the forest land was obtained and the water consumption of this P. euphratica forest, in the lower reaches of the Heihe River, calculated as 214.9 mm by standard specific conductivity of the sample tree.