The impact of growth at elevated [CO2] on stomatal anatomy and behavior differs between wheat species and cultivars.

The ability of plants to respond to changes in the environment is crucial to their survival and reproductive success. The impact of increasing the atmospheric CO2 concentration (a[CO2]), mediated by behavioral and developmental responses of stomata, on crop performance remains a concern under all climate change scenarios, with potential impacts on future food security. To identify possible beneficial traits that could be exploited for future breeding, phenotypic variation in morphological traits including stomatal size and density, as well as physiological responses and, critically, the effect of growth [CO2] on these traits, was assessed in six wheat relative accessions (including Aegilops tauschii, Triticum turgidum ssp.

Longer epidermal cells underlie a quantitative source of variation in wheat flag leaf size.

The wheat flag leaf is the main contributor of photosynthetic assimilates to developing grains. Understanding how canopy architecture strategies affect source strength and yield will aid improved crop design. We used an eight-founder population to investigate the genetic architecture of flag leaf area, length, width and angle in European wheat.

3dCAP-Wheat: An Open-Source Comprehensive Computational Framework Precisely Quantifies Wheat Foliar, Nonfoliar, and Canopy Photosynthesis.

Canopy photosynthesis is the sum of photosynthesis of all above-ground photosynthetic tissues. Quantitative roles of nonfoliar tissues in canopy photosynthesis remain elusive due to methodology limitations. Here, we develop the first canopy photosynthesis model incorporating all above-ground photosynthetic tissues and validate this model on wheat with state-of-the-art gas exchange measurement facilities.

Self-Assembly of a Triphenylene-Based Electron Donor Molecule on Graphene: Structural and Electronic Properties.

In this study, we report on the self-assembly of the organic electron donor 2,3,6,7,10,11-hexamethoxytriphenylene (HAT) on graphene grown epitaxially on Ir(111). Using scanning tunneling microscopy and low-energy electron diffraction, we find that a monolayer of HAT assembles in a commensurate close-packed hexagonal network on graphene/Ir(111). X-ray and ultraviolet photoelectron spectroscopy measurements indicate that no charge transfer between the HAT molecules and the graphene/Ir(111) substrate takes place, while the work function decreases slightly.

Stomata on the abaxial and adaxial leaf surfaces contribute differently to leaf gas exchange and photosynthesis in wheat.

Although stomata are typically found in greater numbers on the abaxial surface, wheat flag leaves have greater densities on the adaxial surface. We determine the impact of this less common stomatal patterning on gaseous fluxes using a novel chamber that simultaneously measures both leaf surfaces. Using a combination of differential illuminations and CO concentrations at each leaf surface, we found that mesophyll cells associated with the adaxial leaf surface have a higher photosynthetic capacity than those associated with the abaxial leaf surface, which is supported by an increased stomatal conductance (driven by differences in stomatal density).

Diurnal and Seasonal Variations of Photosynthetic Energy Conversion Efficiency of Field Grown Wheat.

Improving canopy photosynthetic light use efficiency and energy conversion efficiency (ε ) is a major option to increase crop yield potential. However, so far, the diurnal and seasonal variations of canopy light use efficiency (LUE) and ε are largely unknown due to the lack of an efficient method to estimate ε in a high temporal resolution. Here we quantified the dynamic changes of crop canopy LUE and ε during a day and a growing season with the canopy gas exchange method.

Atomically precise graphene nanoribbons: interplay of structural and electronic properties.

Graphene nanoribbons hold great promise for future applications in nanoelectronic devices, as they may combine the excellent electronic properties of graphene with the opening of an electronic band gap - not present in graphene but required for transistor applications. With a two-step on-surface synthesis process, graphene nanoribbons can be fabricated with atomic precision, allowing precise control over width and edge structure. Meanwhile, a decade of research has resulted in a plethora of graphene nanoribbons having various structural and electronic properties.

SANS study of mixed cholesteric cellulose nanocrystal - gold nanorod suspensions.

Self-assembly of cellulose nanocrystals (CNCs) doped with anisotropic gold nanorods (AuNRs) was studied by small-angle neutron scattering. Correlation distances and structured domains were analysed to determine the influence of CNC and AuNR concentration on structuring. The transfer of the nematic structure of CNCs to AuNRs is explained in terms of an entropy-driven evolution from an isotropic to a cholesteric phase, with small nematic domains already present in the "isotropic" phase in equilibrium with the chiral nematic phase.

A semi-analytical approach for the characterization of ordered 3D nanostructures using grazing-incidence X-ray fluorescence.

Following the recent demonstration of grazing-incidence X-ray fluorescence (GIXRF)-based characterization of the 3D atomic distribution of different elements and dimensional parameters of periodic nanoscale structures, this work presents a new computational scheme for the simulation of the angular-dependent fluorescence intensities from such periodic 2D and 3D nanoscale structures. The computational scheme is based on the dynamical diffraction theory in many-beam approximation, which allows a semi-analytical solution to the Sherman equation to be derived in a linear-algebraic form. The computational scheme has been used to analyze recently published GIXRF data measured on 2D SiN lamellar gratings, as well as on periodically structured 3D Cr nanopillars.

A single point mutation in the C-terminal extension of wheat Rubisco activase dramatically reduces ADP inhibition via enhanced ATP binding affinity.

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase (Rca) is a AAA enzyme that uses ATP to remove inhibitors from the active site of Rubisco, the central carboxylation enzyme of photosynthesis. Rca α and β isoforms exist in most higher plant species, with the α isoform being identical to the β form but having an additional 25-45 amino acids at the Rca C terminus, known as the C-terminal extension (CTE). Rca is inhibited by ADP, and the extent of ADP sensitivity of the Rca complex can be modulated by the CTE of the α isoform, particularly in relation to a disulfide bond structure that is specifically reduced by the redox-regulatory enzyme thioredoxin-f.

Thermodynamic Study of Ion-Driven Aggregation of Cellulose Nanocrystals.

The thermodynamics of interactions between cations of the second group of the periodic table and differently negatively charged cellulose nanocrystals was investigated using isothermal titration calorimetry (ITC). The interaction of cations with the negatively charged CNCs was found to be endothermic and driven by an increase in entropy upon adsorption of the ions, due to an increase in degrees of freedom gained by the surface bound water upon ion adsorption. The effect was pH-dependent, showing an increase in enthalpy for cellulose suspensions at near-neutral pH (6.

A Conserved Sequence from Heat-Adapted Species Improves Rubisco Activase Thermostability in Wheat.

The central enzyme of photosynthesis, Rubisco, is regulated by Rubisco activase (Rca). Photosynthesis is impaired during heat stress, and this limitation is often attributed to the heat-labile nature of Rca. We characterized gene expression and protein thermostability for the three Rca isoforms present in wheat (), namely TaRca1-β, TaRca2-α, and TaRca2-β.

Genotypic, Developmental and Environmental Effects on the Rapidity of in Wheat: Impacts on Carbon Gain and Water-Use Efficiency.

Stomata are the primary gatekeepers for CO uptake for photosynthesis and water loss via transpiration and therefore play a central role in crop performance. Although stomatal conductance ( ) and assimilation rate () are often highly correlated, studies have demonstrated an uncoupling between and that can result in sub-optimal physiological processes in dynamic light environments. Wheat ( L.

Grazing-incidence small-angle X-ray scattering study of correlated lateral density fluctuations in W/Si multilayers.

A structural characterization of W/Si multilayers using X-ray reflectivity (XRR), scanning transmission electron microscopy (STEM) and grazing-incidence small-angle X-ray scattering (GISAXS) is presented. STEM images revealed lateral, periodic density fluctuations in the Si layers, which were further analysed using GISAXS. Characteristic parameters of the fluctuations such as average distance between neighbouring fluctuations, average size and lateral distribution of their position were obtained by fitting numerical simulations to the measured scattering images, and these parameters are in good agreement with the STEM observations.

Anisotropic Diffusion and Phase Behavior of Cellulose Nanocrystal Suspensions.

In this paper, we use dynamic light scattering in polarized and depolarized modes to determine the translational and rotational diffusion coefficients of concentrated rodlike cellulose nanocrystals in aqueous suspension. Within the range of studied concentrations (1-5 wt %), the suspension starts a phase transition from an isotropic to an anisotropic state as shown by polarized light microscopy and viscosity measurements. Small-angle neutron scattering measurements also confirmed the start of cellulose nanocrystal alignment and a decreasing distance between the cellulose nanocrystals with increasing concentration.

A Thermotolerant Variant of Rubisco Activase From a Wild Relative Improves Growth and Seed Yield in Rice Under Heat Stress.

Genes encoding thermostable variants of the photosynthesis heat-labile protein Rubisco activase (Rca) from a wild relative were overexpressed in domesticated rice (). Proteomics was used to quantify the abundance of Rca (Rca-) in the resulting plants. Plants were grown to maturity in growth rooms and from early tillering until immediately prior to anthesis, they were exposed to daytime maximum temperatures of 28, 40, and 45°C and constant night temperatures of 22°C.

Effect of Gelation on the Colloidal Deposition of Cellulose Nanocrystal Films.

One of the most important aspects in controlling colloidal deposition is manipulating the homogeneity of the deposit by avoiding the coffee-ring effect caused by capillary flow inside the droplet during drying. After our previous work where we achieved homogeneous deposition of cellulose nanocrystals (CNCs) from a colloidal suspension by reinforcing Marangoni flow over the internal capillary flow (Gençer et al. Langmuir 2017, 33 (1), 228-234), we now set out to reduce the importance of capillary flow inside a drying droplet by inducing gelation.

Critical amino acids for the insecticidal activity of Vip3Af from Bacillus thuringiensis: Inference on structural aspects.

Vip3 vegetative insecticidal proteins from Bacillus thuringiensis are an important tool for crop protection against caterpillar pests in IPM strategies. While there is wide consensus on their general mode of action, the details of their mode of action are not completely elucidated and their structure remains unknown. In this work the alanine scanning technique was performed on 558 out of the total of 788 amino acids of the Vip3Af1 protein.

Comparative analysis of the susceptibility/tolerance of Spodoptera littoralis to Vip3Aa, Vip3Ae, Vip3Ad and Vip3Af toxins of Bacillus thuringiensis.

The cotton leaf worm Spodoptera littoralis is known for causing serious damages to various crops. In this study, the susceptibility/tolerance of this larvae to four Vip3A (Vip3Aa, Vip3Ae, Vip3Ad and Vip3Af) toxins was investigated. UnlikeVip3Ad which showed no activity to S.

Cellulose-gold nanoparticle hybrid materials.

Cellulose and gold nanoparticles have exciting characteristics and new combinations of both materials may lead to promising functional nanocomposites with unique properties. We have reviewed current research on cellulose-gold nanoparticle composite materials, and we present an overview of the preparation methods of cellulose-gold composite materials and discuss their applications. We start with the nanocomposite fabrication methods, covering in situ gold reduction, blending, and dip-coating methods to prepare gold-cellulose nanocomposite hybrids.

Heat tolerance in a wild Oryza species is attributed to maintenance of Rubisco activation by a thermally stable Rubisco activase ortholog.

The mechanistic basis of tolerance to heat stress was investigated in Oryza sativa and two wild rice species, Oryza meridionalis and Oryza australiensis. The wild relatives are endemic to the hot, arid Australian savannah. Leaf elongation rates and gas exchange were measured during short periods of supra-optimal heat, revealing species differences.

Effect of carbohydrates and night temperature on night respiration in rice.

Global warming causes night temperature (NT) to increase faster than day temperature in the tropics. According to crop growth models, respiration incurs a loss of 40-60% of photosynthate. The thermal sensitivity of night respiration (R(n)) will thus reduce biomass.

Cryogel-PCL combination scaffolds for bone tissue repair.

The present work describes the development and the evaluation of cryogel-poly-ε-caprolactone combinatory scaffolds for bone tissue engineering. Gelatin was selected as cell-interactive biopolymer to enable the adhesion and the proliferation of mouse calvaria pre-osteoblasts while poly-ε-caprolactone was applied for its mechanical strength required for the envisaged application. In order to realize suitable osteoblast carriers, methacrylamide-functionalized gelatin was introduced into 3D printed poly-ε-caprolactone scaffolds created using the Bioplotter technology, followed by performing a cryogenic treatment which was concomitant with the redox-initiated, covalent crosslinking of the gelatin derivative (i.