Mapping of drought-induced changes in tissue characteristics across the leaf profile of Populus balsamifera.

Leaf architecture impacts gas diffusion, biochemical processes, and photosynthesis. For balsam poplar, a widespread North American species, the influence of water availability on leaf anatomy and subsequent photosynthetic performance remains unknown. To address this shortcoming, we characterized the anatomical changes across the leaf profile in three-dimensional space for saplings subjected to soil drying and rewatering using X-ray microcomputed tomography.

Effect of fluid elasticity on the emergence of oscillations in an active elastic filament.

Many microorganisms propel themselves through complex media by deforming their flagella. The beat is thought to emerge from interactions between forces of the surrounding fluid, the passive elastic response from deformations of the flagellum and active forces from internal molecular motors. The beat varies in response to changes in the fluid rheology, including elasticity, but there are limited data on how systematic changes in elasticity alter the beat.

Likelihood of using phytoremediation for mine-tailing management in Chile.

Chile has more than 750 mine tailings across the country, mainly distributed in the northern region, which also includes a biodiversity hotspot and the driest desert in the world. So far, tailing management has included chemical and physical stabilization of tailings, exclusively. This research examined the perceived likelihood of stakeholders, namely: Academia, Industry, environmental Non-Governmental Organizations, and Government officials, in the management of tailings and explored their attitudes toward the inclusion of plants and their associated microbes, as an additional stabilization technology, through an online questionnaire ( = 43).

Tracking Mechanical Stress and Cell Migration with Inexpensive Polymer Thin-Film Sensors.

Polydiacetylene (PDA) Langmuir films are well known for their blue to red chromatic transitions in response to a variety of stimuli, including UV light, heat, bio-molecule bindings and mechanical stress. In this work, we detail the ability to tune PDA Langmuir films to exhibit discrete chromatic transitions in response to applied mechanical stress. Normal and shear-induced transitions were quantified using the Surface Forces Apparatus and established to be binary and tunable as a function of film formation conditions.

Nitrogen isotope discrimination in open-pollinated and hybrid canola suggests indirect selection for enhanced ammonium utilization.

Nitrogen isotope discrimination (ΔN) may have utility as an indicator of nitrogen use in plants. A simple ΔN-based isotope mass balance (IMB) model has been proposed to provide estimates of efflux/influx (/) ratios across root plasma membranes, the proportion of inorganic nitrogen assimilation in roots ( ) and translocation of inorganic nitrogen to shoots (/) under steady-state conditions. We used the IMB model to investigate whether direct selection for yield in canola ( L.

Effects of Fruit Shading on Gene and Protein Expression During Starch and Oil Accumulation in Developing Kernels.

has great potential as a biofuel feedstock source having industrial oilseeds with excellent fatty acids (FAs) composition and good fuel properties. Photosynthesis in the developing pericarp could affect the carbon distribution in kernel. During kernel development, more carbon sources are allocated to starch rather than lipid, when the pericarp photosynthesis is reduced by fruit shading treatment.

Enlightening the Pathway of Phytoremediation: Ecophysiology and X-ray Fluorescence Visualization of Two Chilean Hardwoods Exposed to Excess Copper.

In the present climate emergency due to global warming, we are urged to move away from fossil fuels and pursue a speedy conversion to renewable energy systems. Consequently, copper (Cu) will remain in high demand because it is a highly efficient conductor used in clean energy systems to generate power from solar, hydro, thermal and wind energy across the world. Chile is the global leader in copper production, but this position has resulted in Chile having several hundred tailing deposits.

Proteomic analysis of metabolic mechanisms associated with fatty acid biosynthesis during Styrax tonkinensis kernel development.

Background: Styrax tonkinensis is a white-flowered tree with considerable potential as a feedstock source for biodiesel production from the oily seed contained within its nutlike drupes. Transcriptome changes during oil accumulation have been previously reported, but not concurrent changes in the proteome.

Results: Using proteomic analysis of samples collected at 50, 70, 100 and 130 days after flowering (DAF), we identified 1472 differentially expressed proteins (DEPs).

Genotypic variation in C and N isotope discrimination suggests local adaptation of heart-leaved willow.

Plants acquire multiple resources from the environment and may need to adjust and/or balance their respective resource-use efficiencies to maximize grow and survival, in a locally adaptive manner. In this study, tissue and whole-plant carbon (C) isotopic composition (δ13C) and carbon/nitrogen (C/N) ratios provided long-term measures of use efficiencies for water (WUE) and nitrogen (NUE), and a nitrogen (N) isotopic composition (δ15N)-based mass balance model was used to estimate traits related to N uptake and assimilation in heart-leaved willow (Salix eriocephala Michx.).

Growth response, uptake and mobilization of metals in native plant species on tailings at a Chilean copper mine.

Chile has many mine tailing deposits available for phytoremediation through the establishment of metal-tolerant plants. To guide such efforts, it is necessary to know whether roots exclude or take up metals, or if metals are mobilized to shoots. We evaluated a polyculture of ten native species 6 years after they were planted directly into tailings, amended with mycorrhiza before planting or planted with compost.

Physiological Response of and to Salinity and Hydraulic Fracturing Wastewater: Potential for Phytoremediation Applications.

Natural and anthropogenic soil degradation is resulting in a substantial rise in the extension of saline and industrially-polluted soils. Phytoremediation offers an environmentally and economically advantageous solution to soil contamination. Three growth trials were conducted to assess the stress tolerance of native Canadian genotypes of L.

Isotopic composition and concentration of total nitrogen and nitrate in xylem sap under near steady-state hydroponics.

After root uptake, nitrate is effluxed back to the medium, assimilated locally, or translocated to shoots. Rooted black cottonwood (Populus trichocarpa) scions were supplied with a NO -based (0.5 mM) nutrient medium of known isotopic composition (δ N), and xylem sap was collected by pressure bombing.

Transcriptome analysis of metabolic pathways associated with oil accumulation in developing seed kernels of Styrax tonkinensis, a woody biodiesel species.

Background: Styrax tonkinensis (Pierre) Craib ex Hartwich has great potential as a woody biodiesel species having seed kernels with high oil content, excellent fatty acid composition and good fuel properties. However, no transcriptome information is available on the molecular regulatory mechanism of oil accumulation in developing S. tonkinensis kernels.

Differences in growth and physiological and metabolic responses among Canadian native and hybrid willows (Salix spp.) under salinity stress.

Globally, soil salinization is becoming increasingly prevalent, due to local hydrogeologic phenomena, climate change and anthropogenic activities. This has significantly curtailed current world food production and limits future production potential. In the prairie region of North America, sulfate salts, rather than sodium chloride, are often the predominant cause of soil degradation.

Emerging roles for carbonic anhydrase in mesophyll conductance and photosynthesis.

Carbonic anhydrase (CA) is an abundant protein in most photosynthesizing organisms and higher plants. This review paper considers the physiological importance of the more abundant CA isoforms in photosynthesis, through their effects on CO diffusion and other processes in photosynthetic organisms. In plants, CA has multiple isoforms in three different families (α, β and γ) and is mainly known to catalyze the CO equilibrium.

A role for SPEECHLESS in the integration of leaf stomatal patterning with the growth vs disease trade-off in poplar.

Occurrence of stomata on both leaf surfaces (amphistomaty) promotes higher stomatal conductance and photosynthesis while simultaneously increasing exposure to potential disease agents in black cottonwood (Populus trichocarpa). A genome-wide association study (GWAS) with 2.2M single nucleotide polymorphisms generated through whole-genome sequencing found 280 loci associated with variation in adaxial stomatal traits, implicating genes regulating stomatal development and behavior.

Author Correction: Sexual homomorphism in dioecious trees: extensive tests fail to detect sexual dimorphism in Populus.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Ecological genomics of variation in bud-break phenology and mechanisms of response to climate warming in Populus trichocarpa.

Spring bud-break phenology is a critical adaptive feature common to temperate perennial woody plants. Understanding the molecular underpinnings of variation in bud-break is important for elucidating adaptive evolution and predicting outcomes relating to climate change. Field and controlled growth chamber tests were used to assess population-wide patterns in bud-break from wild-sourced black cottonwood (Populus trichocarpa) genotypes.

The influence of soluble fragments of extracellular matrix (ECM) on tumor growth and morphology.

A major challenge in matrix-metalloproteinase (MMP) target validation and MMP-inhibitor-drug development for anti-cancer clinical trials is to better understand their complex roles (often competing with each other) in tumor progression. While there is extensive research on the growth-promoting effects of MMPs, the growth-inhibiting effects of MMPs has not been investigated thoroughly. So we develop a continuum model of tumor growth and invasion including chemotaxis and haptotaxis in order to examine the complex interaction between the tumor and its host microenvironment and to explore the inhibiting influence of the gradients of soluble fragments of extracellular matrix (ECM) density on tumor growth and morphology.

Flagellar swimming in viscoelastic fluids: role of fluid elastic stress revealed by simulations based on experimental data.

Many important biological functions depend on microorganisms' ability to move in viscoelastic fluids such as mucus and wet soil. The effects of fluid elasticity on motility remain poorly understood, partly because the swimmer strokes depend on the properties of the fluid medium, which obfuscates the mechanisms responsible for observed behavioural changes. In this study, we use experimental data on the gaits of swimming in Newtonian and viscoelastic fluids as inputs to numerical simulations that decouple the swimmer gait and fluid type in order to isolate the effect of fluid elasticity on swimming.

Mechanosensitive Adhesion Explains Stepping Motility in Amoeboid Cells.

Cells employing amoeboid motility exhibit repetitive cycles of rapid expansion and contraction and apply coordinated traction forces to their environment. Although aspects of this process are well studied, it is unclear how the cell controls the coordination of cell length changes with adhesion to the surface. Here, we develop a simple model to mechanistically explain the emergence of periodic changes in length and spatiotemporal dynamics of traction forces measured in chemotaxing unicellular amoeba, Dictyostelium discoideum.

Self-organized mechano-chemical dynamics in amoeboid locomotion of fragments.

The aim of this work is to quantify the spatio-temporal dynamics of flow-driven amoeboid locomotion in small (~100 µm) fragments of the true slime mold . In this model organism, cellular contraction drives intracellular flows, and these flows transport the chemical signals that regulate contraction in the first place. As a consequence of these non-linear interactions, a diversity of migratory behaviors can be observed in migrating fragments.