Genet diversity, genetic structure, and trait expression of trembling aspen (Populus tremuloides Michx.) after clear-cut harvesting and post-harvest soil treatments

Botany ◽  
2017 ◽  
Vol 95 (8) ◽  
pp. 785-798
Author(s):  
Mehmet Acet ◽  
Martin F. Jurgensen ◽  
Evan Kane ◽  
Oliver Gailing
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Populus Tremuloides ◽  
Soil Compaction ◽  
Phenotypic Trait ◽  
Phenotypic Traits ◽  
Soil Productivity ◽  
Trembling Aspen ◽  
Clear Cut ◽  
Heavy Soil

Trembling aspen is a fast growing, broadly distributed tree in North America that reproduces by root suckers (clonally) and by seeds (sexually). Since timber harvesting can affect both reproduction pathways by changing the soil properties, we assessed genet diversity, genetic structure, and phenotypic trait expression of trembling aspen populations after clear-cut harvesting in a long-term soil productivity study site in Michigan. A total of 323 stems in replicated plots having heavy soil compaction and surface organic matter (OM) removed, and the untreated controls, were analyzed at microsatellites and for phenotypic traits. Overall, higher spatial aggregation of ramets from the same genet, a greater spatial separation of different genets, and a very good phenotypic separation among genets was observed in the treatment plots. In contrast, for plots with spatially intermixed clones phenotypic separation was much lower. Genetic differentiation was high between individual plots, but soil compaction and OM removal had little effect on genetic differentiation and diversity. One treatment plot was strongly differentiated phenotypically, but not genetically, from all other plots. Consequently, microenvironmental and genetic differences should be considered when forest management effects on trait expressions and productivity are analyzed. Overall, heavy soil compaction and OM removal in fine-textured soil seemed to have restricted the spread of aspen clones.

scholarly journals Normal approximation for mixtures of normal distributions and the evolution of phenotypic traits

2021 ◽  
Vol 53 (1) ◽  
pp. 162-188
Author(s):  
Krzysztof Bartoszek ◽  
Torkel Erhardsson
Keyword(s):  
Normal Distribution ◽  
Phenotypic Trait ◽  
Phenotypic Traits ◽  
Normal Distributions ◽  
Average Value ◽  
Conditional Moments ◽  
Mixture Of Normal Distributions ◽  
Explicit Bounds ◽  
Mixtures Of Normal Distributions ◽  
Parameter Values

AbstractExplicit bounds are given for the Kolmogorov and Wasserstein distances between a mixture of normal distributions, by which we mean that the conditional distribution given some $\sigma$ -algebra is normal, and a normal distribution with properly chosen parameter values. The bounds depend only on the first two moments of the first two conditional moments given the $\sigma$ -algebra. The proof is based on Stein’s method. As an application, we consider the Yule–Ornstein–Uhlenbeck model, used in the field of phylogenetic comparative methods. We obtain bounds for both distances between the distribution of the average value of a phenotypic trait over n related species, and a normal distribution. The bounds imply and extend earlier limit theorems by Bartoszek and Sagitov.

scholarly journals Ethylene enhances root water transport and aquaporin expression in trembling aspen (Populus tremuloides) exposed to root hypoxia

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiangfeng Tan ◽  
Mengmeng Liu ◽  
Ning Du ◽  
Janusz J. Zwiazek
Keyword(s):  
Gas Exchange ◽  
Water Transport ◽  
Populus Tremuloides ◽  
Leaf Gas Exchange ◽  
Hydraulic Conductance ◽  
Root Hydraulic Conductance ◽  
Trembling Aspen ◽  
Expression Levels ◽  
Root Hypoxia ◽  
Exogenous Ethylene

Abstract Background Root hypoxia has detrimental effects on physiological processes and growth in most plants. The effects of hypoxia can be partly alleviated by ethylene. However, the tolerance mechanisms contributing to the ethylene-mediated hypoxia tolerance in plants remain poorly understood. Results In this study, we examined the effects of root hypoxia and exogenous ethylene treatments on leaf gas exchange, root hydraulic conductance, and the expression levels of several aquaporins of the plasma membrane intrinsic protein group (PIP) in trembling aspen (Populus tremuloides) seedlings. Ethylene enhanced net photosynthetic rates, transpiration rates, and root hydraulic conductance in hypoxic plants. Of the two subgroups of PIPs (PIP1 and PIP2), the protein abundance of PIP2s and the transcript abundance of PIP2;4 and PIP2;5 were higher in ethylene-treated trembling aspen roots compared with non-treated roots under hypoxia. The increases in the expression levels of these aquaporins could potentially facilitate root water transport. The enhanced root water transport by ethylene was likely responsible for the increase in leaf gas exchange of the hypoxic plants. Conclusions Exogenous ethylene enhanced root water transport and the expression levels of PIP2;4 and PIP2;5 in hypoxic roots of trembling aspen. The results suggest that ethylene facilitates the aquaporin-mediated water transport in plants exposed to root hypoxia.

The bacteria in sapwood, wetwood, and heartwood of trembling aspen (Populus tremuloides)

1973 ◽  
Vol 51 (2) ◽  
pp. 498-500 ◽  
Author(s):  
Donald M. Knutson
Keyword(s):  
Populus Tremuloides ◽  
Trembling Aspen ◽  
Indigenous Bacteria ◽  
Large Populations ◽  
Xylem Tissue

Bacteria (Erwinia, Bacillus) were consistently isolated from all samples of aspen sapwood and heartwood. In wetwood zones (water-soaked xylem tissue) or discolored heartwood, large populations often occur. No organisms unique to wetwood were isolated. Wetwood probably is formed by nonmicrobial means and, once formed, merely supports large populations of indigenous bacteria.

Wounding of aspen roots promotes suckering

2004 ◽  
Vol 82 (3) ◽  
pp. 310-315 ◽  
Author(s):  
Erin C Fraser ◽  
Victor J Lieffers ◽  
Simon M Landhäusser
Keyword(s):  
Populus Tremuloides ◽  
Growth Rates ◽  
Growing Season ◽  
Organic Layer ◽  
Trembling Aspen ◽  
Layer Depth ◽  
Injury Type ◽  
Organic Layers ◽  
Root Injury ◽  
Root Sucker

In early May, 1-m sections of trembling aspen (Populus tremuloides Michx.) roots in a forest cutblock were carefully exposed and examined for damage. Undamaged roots were subjected to one of three wounding treatments (scrape, sever, or uninjured control) and were then reburied to either the full normal organic layer depth or to one third of the normal depth. Following one growing season, the roots were reexposed and assessed for aspen sucker numbers and growth rates. Results indicate that injured roots produced suckers nearly twice as often as uninjured roots. Further, injured roots produced more suckers per root, and these suckers were taller and had greater leaf area. Roots buried under shallow organic layers also generated more suckers, regardless of injury type. The side of injury (distal or proximal) did not affect any of the measured variables. The present study suggests that moderate wounding of aspen roots increases initial sucker numbers and growth rates.Key words: trembling aspen, root sucker, root injury, regeneration.

Contrasting patterns of genetic structure and disequilibrium in populations of a stone-cased caddisfly (Tasimiidae) from northern and southern Australia

2008 ◽  
Vol 59 (3) ◽  
pp. 235 ◽  
Author(s):  
Alicia Slater Schultheis ◽  
Richard Marchant ◽  
Jane Margaret Hughes
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Adult Emergence ◽  
Conclusive Evidence ◽  
Emergence Patterns ◽  
Freshwater Invertebrate ◽  
Gene Coi ◽  
Hardy Weinberg Equilibrium ◽  
New Recruits ◽  
Genetic Patchiness

In marine and freshwater invertebrate populations, microscale genetic differentiation or ‘genetic patchiness’ is thought to result from variation in the abundance and genetic composition of new recruits at a particular location. In the present study, the role of the adult emergence patterns in genetic patchiness was examined using mtDNA and two microsatellite loci to compare patterns of genetic differentiation in asynchronously (subtropical) and synchronously emerging (temperate) populations of the stone-cased caddisfly Tasimia palpata. A 550 base pair region of the mitochondrial cytochrome c oxidase subunit I gene (COI) was sequenced in at least 14 individuals from each population. Genetic structure was detected only at the reach scale in the subtropical populations and no genetic differentiation was detected in temperate populations. There were more deviations from Hardy–Weinberg equilibrium (HWE) in subtropical populations than in temperate populations where 44% and 12.5%, respectively, of tests for deviations from HWE were significant. Although distinct patterns of genetic structure and deviations from HWE were observed in the subtropical and temperate populations of T. palpata, no conclusive evidence was found to suggest that the differences are caused by differences in emergence patterns. We hypothesise that genetic patchiness must be caused by post-recruitment processes, most likely the preservation of oviposition ‘hotspots’ in subtropical streams.

THE BEHAVIOUR OF FIVE WOOD SPECIES IN COMPRESSION

IAWA Journal ◽  
2002 ◽  
Vol 23 (2) ◽  
pp. 201-211 ◽  
Author(s):  
Simon Ellis ◽  
Paul Steiner
Keyword(s):  
Young’S Modulus ◽  
Populus Tremuloides ◽  
Wood Species ◽  
Young's Modulus ◽  
Douglas Fir ◽  
Thuja Plicata ◽  
Trembling Aspen ◽  
Moisture Contents ◽  
Red Cedar ◽  
Western Red Cedar

Five wood species, Oregon ash (Fraxinus latifolia Benth.), Balau (Shorea spp.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Western red cedar (Thuja plicata Donn ex D. Don), and Trembling aspen (Populus tremuloides Michx.) were loaded in compression longitudinally, radially and tangentially. The wood cubes were conditioned to one of four moisture contents prior to loading. Small cubes were loaded until no void space remained after which samples were released and soaked in water. Stress /strain curves were recorded over the whole range of strain and cube thicknesses were recorded at the end of the compression, after release from the testing apparatus, and after soaking in water. Denser woods resulted in a greater Young’s modulus, higher levels of stress and shorter time to densification than did less dense woods. Higher initial moisture contents apparently increased the plasticity of the wood leading to a lower Young’s modulus and lower levels of stress during compression, greater springback after release of stress and greater recovery after swelling in water. Differences observed in the radial and tangential behaviours were believed to be due to the supporting action of the rays when the wood was compressed in the radial direction in balau and trembling aspen and to the relative difference between the lower density earlywood and higher density latewood regions in ash, Douglas-fir and western red cedar.

scholarly journals Population Genetics and Evolution Analysis Reveal Diversity and Origin of Ammopiptanthus in China.

2021 ◽  
Author(s):  
Guai-qiang Chai ◽  
Yizhong Duan ◽  
Peipei Jiao ◽  
Zhongyu Du ◽  
Furen Kang
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Association Studies ◽  
Natural Populations ◽  
Principal Component ◽  
Nucleotide Polymorphisms ◽  
Future Design ◽  
Ammopiptanthus Nanus ◽  
Genome Wide

Abstract Background：Elucidating and revealing the population genetic structure, genetic diversity and recombination is essential for understanding the evolution and adaptation of species. Ammopiptanthus, which is an endangered survivor from the Tethys in the Tertiary Period, is the only evergreen broadleaf shrub grown in Northwest of China. However, little is known about its genetic diversity and underlying adaptation mechanisms. Results：Here, 111 Ammopiptanthus individuals collected from fifteen natural populations in estern China were analyzed by means of the specific locus amplified fragment sequencing (SLAF-seq). Based on the single nucleotide polymorphisms (SNPs) and insertions and deletions (InDels) detected by SLAF-seq, genetic diversity and markers associated with climate and geographical distribution variables were identified. The results of genetic diversity and genetic differentiation revealed that all fifteen populations showed medium genetic diversity, with PIC values ranging from 0.1648 to 0.3081. AMOVA and Fst indicated that a low genetic differentiation existed among populations. Phylogenetic analysis showed that NX-BG and NMG-DQH of fifteen populations have the highest homology，while the genetic structure analysis revealed that these Ammopiptanthus germplasm accessions were structured primarily along the basis of their geographic collection, and that an extensive admixture occurred in each group. In addition, the genome-wide linkage disequilibrium (LD) and principal component analysis showed that Ammopiptanthus nanus had a more diverse genomic background, and all genetic populations were clearly distinguished, although different degrees of introgression were detected in these groups. Conclusion：Our study could provide guidance to the future design of association studies and the systematic utilization and protection of the genetic variation characterizing the Ammopiptanthus.

scholarly journals A differential expression of pyrethroid resistance genes in the malaria vector Anopheles funestus across Uganda is associated with patterns of gene flow

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0240743
Author(s):  
Maurice Marcel Sandeu ◽  
Charles Mulamba ◽  
Gareth D. Weedall ◽  
Charles S. Wondji
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Insecticide Resistance ◽  
Pyrethroid Resistance ◽  
Anopheles Funestus ◽  
Metabolic Resistance ◽  
Transcription Analysis ◽  
Genome Wide

Background Insecticide resistance is challenging the effectiveness of insecticide-based control interventions to reduce malaria burden in Africa. Understanding the molecular basis of insecticides resistance and patterns of gene flow in major malaria vectors such as Anopheles funestus are important steps for designing effective resistance management strategies. Here, we investigated the association between patterns of genetic structure and expression profiles of genes involved in the pyrethroid resistance in An. funestus across Uganda and neighboring Kenya. Methods Blood-fed mosquitoes An. funestus were collected across the four localities in Uganda and neighboring Kenya. A Microarray-based genome-wide transcription analysis was performed to identify the set of genes associated with permethrin resistance. 17 microsatellites markers were genotyped and used to establish patterns of genetic differentiation. Results Microarray-based genome-wide transcription profiling of pyrethroid resistance in four locations across Uganda (Arua, Bulambuli, Lira, and Tororo) and Kenya (Kisumu) revealed that resistance was mainly driven by metabolic resistance. The most commonly up-regulated genes in pyrethroid resistance mosquitoes include cytochrome P450s (CYP9K1, CYP6M7, CYP4H18, CYP4H17, CYP4C36). However, expression levels of key genes vary geographically such as the P450 CYP6M7 [Fold-change (FC) = 115.8 (Arua) vs 24.05 (Tororo) and 16.9 (Kisumu)]. In addition, several genes from other families were also over-expressed including Glutathione S-transferases (GSTs), carboxylesterases, trypsin, glycogenin, and nucleotide binding protein which probably contribute to insecticide resistance across Uganda and Kenya. Genotyping of 17 microsatellite loci in the five locations provided evidence that a geographical shift in the resistance mechanisms could be associated with patterns of population structure throughout East Africa. Genetic and population structure analyses indicated significant genetic differentiation between Arua and other localities (FST>0.03) and revealed a barrier to gene flow between Arua and other areas, possibly associated with Rift Valley. Conclusion The correlation between patterns of genetic structure and variation in gene expression could be used to inform future interventions especially as new insecticides are gradually introduced.

Annual differences in quality of leaf litter of aspen (Populus tremuloides) affecting rates of decomposition

1988 ◽  
Vol 66 (10) ◽  
pp. 1940-1947 ◽  
Author(s):  
Barry R. Taylor ◽  
Dennis Parkinson
Keyword(s):  
Water Absorption ◽  
Leaf Litter ◽  
Populus Tremuloides ◽  
Decomposition Rate ◽  
Rocky Mountains ◽  
Absorption Rate ◽  
Trembling Aspen ◽  
Leaching Loss ◽  
The Difference

Freshly fallen leaf litter was collected from a stand of trembling aspen (Populus tremuloides Michx.) in the Rocky Mountains of Alberta each autumn from 1981 through 1984. Leaves from 1981 and 1982 were yellow, waxy, and strong. Leaves from 1983 were pale brown and very brittle, and almost 1% of them suffered symmetrical deformities. Leaves from 1984 were composed of 80% yellow leaves and 20% green leaves, which apparently abscissed before senescence. Green and yellow 1984 leaves were distinctly different with respect to total (3 days) leaching loss, leachate conductivity, and proportions of ash, cellulose, and labile material. Green 1984 leaves contained twice as much nitrogen as yellow ones (13.1 vs. 6.5 mg∙g−1) and significantly more phosphorus (1.6 vs. 1.3 mg∙g−1). Leaves of different years varied widely with respect to leaf mass, water absorption rate, mass and conductivity of leachate, and proportions of cellulose, labiles, lignin, and ash, but there was no consistent ordering among years; leaves of different colouration (especially 1981 and 1983) were often physicochemically similar, while leaves identical in appearance were often chemically different. Small but significant differences in N and P concentrations among years were removed by 2 h leaching. Leaves of 1981 decomposing in laboratory microcosms at 26 °C lost less mass than either 1982 or 1983 leaves after 1 month, but not after 2 months. Ability of the cuticle to resist water absorption was probably responsible for the difference in initial decomposition rate.

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