Systems responses to progressive water stress in durum wheat

Durum wheat is susceptible to terminal drought which can greatly decrease grain yield. Breeding to improve crop yield is hampered by inadequate knowledge of how the physiological and metabolic changes caused by drought are related to gene expression. To gain better insight into mechanisms defining resistance to water stress we studied the physiological and transcriptome responses of three durum breeding lines varying for yield stability under drought. Parents of a mapping population (Lahn x Cham1) and a recombinant inbred line (RIL2219) showed lowered flag leaf relative water content, water potential and photosynthesis when subjected to controlled water stress time transient experiments over a six-day period. RIL2219 lost less water and showed constitutively higher stomatal conductance, photosynthesis, transpiration, abscisic acid content and enhanced osmotic adjustment at equivalent leaf water compared to parents, thus defining a physiological strategy for high yield stability under water stress. Parallel analysis of the flag leaf transcriptome under stress uncovered global trends of early changes in regulatory pathways, reconfiguration of primary and secondary metabolism and lowered expression of transcripts in photosynthesis in all three lines. Differences in the number of genes, magnitude and profile of their expression response were also established amongst the lines with a high number belonging to regulatory pathways. In addition, we documented a large number of genes showing constitutive differences in leaf transcript expression between the genotypes at control non-stress conditions. Principal Coordinates Analysis uncovered a high level of structure in the transcriptome response to water stress in each wheat line suggesting genome-wide co-ordination of transcription. Utilising a systems-based approach of analysing the integrated wheat's response to water stress, in terms of biological robustness theory, the findings suggest that each durum line transcriptome responded to water stress in a genome-specific manner which contributes to an overall different strategy of resistance to water stress

La qualité du blé dur dans la région méditerranéenne

National audienc

Structural characterization and thermal degradation of poly(methylmethacrylate)/zinc oxide nanocomposites

This work is based on the preparation of composites of poly(methylmethacrylate) with zinc oxide nanoparticles synthesized by solution casting method. Chloroform cast poly(methylmethacrylate) films containing different amounts of ZnO nanoparticles were characterized by XRD, SEM, UV-vis spectroscopy, FTIR spectroscopy and TGA. The results show that ZnO nanoparticles with a size of 24 nm were fairly dispersed in the polymer matrix. The obtained material had UV shielding capability with optical transparency. Thermal characterization shows that, the nanocomposites were more thermally stable than pure PMMA presenting three degradation steps. Apparent kinetic parameters were determined for each degradation step using peak fitting methodology. According to activation energies, ZnO particles affect simultaneously but oppositely the kinetics of underlying degradation reactions. Thermal stability of the PMMA/ZnO nanocomposites was the result of the overall balance in favor of the inhibiting effect of ZnO.The authors acknowledge the financial support of CNEPRU project N E00720140050. MALM thanks the support from the MINECO project MAT2016-81138-R. The authors appreciate the assistance of ICTP/ SCIC technical staff.Peer Reviewe

Structural and Thermal Properties of Polycaprolactone/PEG-Coated Zinc Oxide Nanocomposites

Abstract: In this paper, PCL with PEG-coated ZnO nanocomposites films were prepared by solution casting using dichloromethane as a solvent. ZnO nanoparticles of 24 nm crystallite size were synthesized by chemical precipitation method. Surface modification of ZnO NPs was achieved by solution mixing with low molecular weight PEG and verified by FTIR and TGA. The nanocomposites films were characterized by XRD, FTIR, SEM, and TGA techniques. PEG surface modification of ZnO leads to well-dispersed nanoparticles in the polymer matrix. The incorporation of ZnO NPs in PCL alters the thermal stability of the polymer by up to 110°C degradation onset temperature. Non-isothermal kinetic study was performed by model-fitting Coats-Redfern method. The calculated activation energies of the nanocomposites indicate the catalytic effect of ZnO on the thermal decomposition of PCL.The authors would like to acknowledge the assistance of the ICTP-CSIC technical staff

An approach for protecting transport infrastructure

International audienceScientific and technological innovations are often sources of new vulnerabilities, hazards and risks impacting equipment, systems, processes, organization, and human behaviours. The issues of safety, security, performance, and their management in a holistic approach are quickly becoming essential for every industrial sector. This article discusses safety and security policy focused on the protection of critical railway infrastructure. The article suggests a global approach for risk appraisal and threat assessment in the railway sector, and highlights some of the technologies for the monitoring and surveillance of rail linear infrastructures

Absorbed radiation doses due to chronic ingestion of cesium-137 or strontium-90 by mice

The knowledge of the absorbed radiation dose is essential in order to interpret the results of animal experiments with chronic ingestion of radionuclides by rodents. In order to evaluate this absorbed dose, we applied the dose conversion factors proposed by ICRP publication 108 to mouse chronic ingestion experiments with 20 kBq.L-1 137Cs- or 90Sr-contaminated water. The results indicated that whole-body absorbed doses were 9 mGy and 10 mGy by the end of 20 weeks of 137Cs or 90Sr ingestion, respectively. These results of dose calculations were compared with results obtained with a more refined method using published organ-specific absorbed fractions of energy. There was good agreement between the two methods, indicating that, despite the simple hypotheses used to apply the ICRP 108 dose conversion factors to our mouse model, this method allows one to calculate in a simple and reliable way the absorbed radiation dose received by the rodents during long-term experiments on chronic ingestion of radionuclides

Reduction of hydrogen embrittlement of API 5l X65 steel pipe using a green inhibitor

International audienc