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Salt has emerged as a top-ranking threat for agriculture because of the raising awareness of the consequences imposed by climate change. Indeed, sea level rises at an alarming rate and the proportion of saline soils in the world increases dramatically. This is particularly the case in arid and semi-arid regions, where the lack of appropriate irrigation exacerbates soil salinization. In this context, developing sustainable agricultural practices that can counteract the deleterious effects of abiotic stresses has become a top priority.
The constant search of new methods to alleviate the negative effect of stresses in plants has motivated the experimentation of new technologies such as nanotechnologies. It is in this context that the use of a hybrid Si NanoParticles based Biocourier (Si-NPs) acting as a delivery system has been proposed here. Si NanoParticles-based formulations functionalised with quercetin, a plant bioactive, were applied on salt-stressed tomato plants (Solanum lycopersicum cv MicroTom) by foliar spraying to investigate whether they conferred protection against salinity.
Microscopic analysis of salt-stressed tomato plants leaves showed an accumulation of anthocyanins in the abaxial side, as well as smaller xylem vessels and mesophyll cells with a “wrinkly” appearance. The expression of several stress-responsive genes was measured in different leaflets sampled at different heights and positions along the rachis to determine whether changes in stress response could be measured among the different organs. The expression of a set of genes showing the highest induction upon salt stress (200 mM NaCl) was then measured in plants treated with formulations containing Si-NPs functionalised or not with quercetin. Si-NPs containing quercetin helped maintain the cellular structure under salt-stress, especially in the palisade parenchyma. Additionally, a trend towards a decreased expression of stress-responsive genes was observed in the leaves treated with the Si-NPs formulations containing quercetin.
In conclusion, Si-NPs loaded with quercetin showed promising results to enhance abiotic stress resistance in tomato through the mitigation of stress symptoms. Additional studies are required to further elucidate the action of Si-NPs on plant physiology. La salinisation des sols s'est présentée au cours des dernières années comme une des principales menaces qui courent sur l'agriculture, faisant fortement diminuer les rendements agricoles des principales semences à fort intérêt économique. Celle-ci est notamment une conséquence du réchauffement climatique qui provoque la montée du niveau des océans à un rythme effréné, ainsi qu'aux mauvaises pratiques d'irrigation, notamment dans les régions arides et semi-arides du globe. Devant ces constatations, il devient donc urgent de développer de nouveaux moyens pour garantir une agriculture durable qui serait à même de faire face aux effets délétères induits par le réchauffement climatique.
Le besoin perpétuel de trouver de nouvelles manières d'accroître la résistance des plantes aux stress abiotiques a mené à l'utilisation de nouvelles technologies telles que les nanotechnologies. C'est dans cette optique que l'utilisation de formulations hybrides à base de NanoParticules de Si (Si-NPs) servant comme transporteur spécifique de composés bioactifs tels que la quercétine et permettant leur relargage contrôlé a ici été expérimentée. Des plants de tomates (Solanum lycopersicum cv Micro-Tom) soumis à un stress salin ont alors été traités avec ces formulations appliquées par voie foliaire pour déterminer leur efficacité à protéger les plantes des méfaits du sel.
L'analyse microscopique des coupes de feuilles de plants de tomates a montré que l'accumulation d'anthocyanines et l'endommagement des tissus mésophylles et vasculaires étaient les principaux effets dus au stress salin visibles à l'échelle microscopique. L'expression de différents gènes identifiés comme étant réactifs aux conditions de stress a été mesurée dans différentes folioles des feuilles composées de la tomate échantillonnées à différentes hauteurs de la plante et à différentes positions sur le pétiole afin de déterminer la réponse au stress dans ces différents organes. Suite à cela, l'expression des gènes les plus réactifs a été mesurée en traitant les plantes avec les formulations à base de Si-NPs. Ces dernières chargées de quercétine ont permis à la plante de maintenir son intégrité cellulaires en conditions salines, notamment au niveau de son parenchyme palissadique, tout en voyant une tendance de l'induction de l'expression des gènes les plus réactifs à être réduite.
En conclusion, les formulations à base de Si-NPs et chargées de quercétine ont présenté des résultats prometteurs permettant d'accroître la résistance de plants de tomates aux stress abiotiques via la réduction des symptômes dus au stress. Cependant, de plus amples recherches sont toujours nécessaires afin de mieux comprendre les mécaniques d'action des Si-NPs sur les plantes.

Salt-stress --- Micro-Tom --- Si nanoparticle formulations --- Quercetin --- Gene expression analysis --- Optical microscopy --- Sciences du vivant > Biochimie, biophysique & biologie moléculaire

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This book presents a detailed look at experimental and computational techniques for accurate structure determination of free molecules. The most fundamental property of a molecule is its structure – it is a prerequisite for determining and understanding most other important properties of molecules. The determination of accurate structures is hampered by a myriad of factors, subjecting the collected data to non-negligible systematic errors. This book explains the origin of these errors and how to mitigate and even avoid them altogether. It features a detailed comparison of the different experimental and computation methods, explaining their interplay and the advantages of their combined use. Armed with this information, the reader will be able to choose the appropriate methods to determine – to a great degree of accuracy – the relevant molecular structure.

Spectroscopy. --- Atomic structure  . --- Molecular structure . --- Microscopy. --- Crystallography. --- Spectroscopy/Spectrometry. --- Atomic/Molecular Structure and Spectra. --- Spectroscopy and Microscopy. --- Crystallography and Scattering Methods. --- Leptology --- Physical sciences --- Mineralogy --- Analysis, Microscopic --- Light microscopy --- Micrographic analysis --- Microscope and microscopy --- Microscopic analysis --- Optical microscopy --- Optics --- Structure, Molecular --- Chemical structure --- Structural bioinformatics --- Structure, Atomic --- Atomic theory --- Analysis, Spectrum --- Spectra --- Spectrochemical analysis --- Spectrochemistry --- Spectrometry --- Spectroscopy --- Chemistry, Analytic --- Interferometry --- Radiation --- Wave-motion, Theory of --- Absorption spectra --- Light --- Spectroscope --- Qualitative --- Analytical chemistry --- Molecular structure. --- Free molecules. --- Spectrum analysis. --- Molecules

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The book presents new data on the IR spectra of minerals and on the Raman spectra of more than 2000 mineral species. It also includes examples of IR spectroscopy applications to investigate minerals, and discusses the most important potential applications of Raman spectroscopy in mineralogical research. The book serves as a reference resource and a methodological guide for mineralogists, petrologists and technologists working in the field of inorganic materials.

Minerals --- Mineralogy --- Mines and mineral resources --- Spectra. --- Mineralogy. --- Spectroscopy. --- Microscopy. --- Ceramics. --- Glass. --- Composites (Materials). --- Composite materials. --- Materials science. --- Spectroscopy and Microscopy. --- Ceramics, Glass, Composites, Natural Materials. --- Characterization and Evaluation of Materials. --- Material science --- Physical sciences --- Composites (Materials) --- Multiphase materials --- Reinforced solids --- Solids, Reinforced --- Two phase materials --- Materials --- Amorphous substances --- Ceramics --- Glazing --- Ceramic technology --- Industrial ceramics --- Keramics --- Building materials --- Chemistry, Technical --- Clay --- Analysis, Microscopic --- Light microscopy --- Micrographic analysis --- Microscope and microscopy --- Microscopic analysis --- Optical microscopy --- Optics --- Analysis, Spectrum --- Spectra --- Spectrochemical analysis --- Spectrochemistry --- Spectrometry --- Spectroscopy --- Chemistry, Analytic --- Interferometry --- Radiation --- Wave-motion, Theory of --- Absorption spectra --- Light --- Spectroscope --- Physical geology --- Crystallography --- Qualitative --- Analytical chemistry --- Spectrum analysis. --- Ceramic materials. --- Characterization and Analytical Technique. --- Analysis. --- Ceramic industries

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This book shows how the fundamentals of electron paramagnetic resonance (EPR) spectroscopy are practically implemented and illustrates the diversity of current applications. The technique is used at various levels, and applications are presented in order of increasing difficulty, with reference to theoretically obtained results. This book features a diverse array of application examples, from fields such as ionizing radiation dosimetry, neurodegenerative diseases, structural transitions in proteins, and the origins of terrestrial life. The final chapter of this book highlights the principles and applications of the technique of ferromagnetic resonance spectroscopy, followed by a brief introduction to advanced EPR techniques such as electron spin echo envelope modulation (ESEEM), hyperfine sub-level correlation (HYSCORE), pulsed electron-electron double resonance (PELDOR), and continuous wave electron nuclear double resonance (ENDOR) experiments.

Spectroscopy. --- Microscopy. --- Atomic structure  . --- Molecular structure . --- Magnetism. --- Magnetic materials. --- Crystallography. --- Physical chemistry. --- Materials science. --- Spectroscopy and Microscopy. --- Atomic/Molecular Structure and Spectra. --- Magnetism, Magnetic Materials. --- Crystallography and Scattering Methods. --- Physical Chemistry. --- Characterization and Evaluation of Materials. --- Material science --- Physical sciences --- Chemistry, Theoretical --- Physical chemistry --- Theoretical chemistry --- Chemistry --- Leptology --- Mineralogy --- Materials --- Mathematical physics --- Physics --- Electricity --- Magnetics --- Structure, Molecular --- Chemical structure --- Structural bioinformatics --- Structure, Atomic --- Atomic theory --- Analysis, Microscopic --- Light microscopy --- Micrographic analysis --- Microscope and microscopy --- Microscopic analysis --- Optical microscopy --- Optics --- Analysis, Spectrum --- Spectra --- Spectrochemical analysis --- Spectrochemistry --- Spectroscopy --- Chemistry, Analytic --- Interferometry --- Radiation --- Wave-motion, Theory of --- Absorption spectra --- Light --- Spectroscope --- Qualitative --- Spectrometry --- Analytical chemistry

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This book is an invaluable guide to calibrating any infrared spectrum using noble gases as a reference. Featuring a detailed graphical and tabular overview of highly excited (Rydberg) states of neutral noble gases in the infrared range of 700–7000 cm-1, it helps researchers by providing high-precision experimental data that can be used in almost every infrared spectroscopic laboratory.

Atomic emission spectroscopy. --- AES (Spectrum analysis) --- Atomic spectroscopy --- Emission spectroscopy --- Atomic structure  . --- Molecular structure . --- Spectroscopy. --- Microscopy. --- Astronomy. --- Astrophysics. --- Physical chemistry. --- Atomic/Molecular Structure and Spectra. --- Spectroscopy/Spectrometry. --- Spectroscopy and Microscopy. --- Astronomy, Astrophysics and Cosmology. --- Physical Chemistry. --- Chemistry, Theoretical --- Physical chemistry --- Theoretical chemistry --- Chemistry --- Astronomical physics --- Astronomy --- Cosmic physics --- Physics --- Analysis, Microscopic --- Light microscopy --- Micrographic analysis --- Microscope and microscopy --- Microscopic analysis --- Optical microscopy --- Optics --- Analysis, Spectrum --- Spectra --- Spectrochemical analysis --- Spectrochemistry --- Spectrometry --- Spectroscopy --- Chemistry, Analytic --- Interferometry --- Radiation --- Wave-motion, Theory of --- Absorption spectra --- Light --- Spectroscope --- Structure, Molecular --- Chemical structure --- Structural bioinformatics --- Structure, Atomic --- Atomic theory --- Qualitative --- Analytical chemistry