Characterization of pearl millet root architecture and anatomy reveals three types of lateral roots

Pearl millet plays an important role for food security in arid regions of Africa and India. Nevertheless, it is considered an orphan crop as it lags far behind other cereals in terms of genetic improvement efforts. Breeding pearl millet varieties with improved root traits promises to deliver benefits in water and nutrient acquisition. Here, we characterize of early pearl millet root system development using several different root phenotyping approaches that include rhizotrons and microCT. We report that early stage pearl millet root system development is characterized by a fast growing primary root that quickly colonizes deeper soil horizons. We also describe root anatomical studies that revealed 3 distinct types of lateral roots that form on both primary roots and crown roots. Finally, we detected significant variation for two root architectural traits in pearl millet inbred lines. This study provides the basis for subsequent genetic experiments to identify loci associated with interesting early root development traits in this important cereal

Raman characterization of singlewalled carbon nanotubes and PMMA-nanotubes composites

The Raman spectroscopy have allowed us to perform studies on singlewalled nanotubes (SWNT's) produced by following methods: electric arc, laser ablation and solar energy. As this characterization method provides a great deal of informations, we will present a comparison between the nanotubes produced by all these processes and the influence of some synthesis parameters. By using spin casting, we have produced thin films of PMMA-SWNT's for different concentrations. Then, we have characterized these new materials by Raman spectroscopy. The aim of these investigations is to get information on the possible interactions between these two materials. In particular, we have studied the evolution of the composites films spectra as a function of the nanotubes concentration in the polymer.This work has been fully supported by the European Community through its Training and Mobility of Researcher program under network contract : NAMITECH, ERBFMRX- CT96-0067 @GlZ-MIHT) and by the tiench CNRS program : ULTIMATECH.Peer reviewe

Mécanismes de croissance et étude vibrationnelle par spectroscopie Raman des nanotubes de carbone produits par la méthode solaire

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Nitrogen-doped carbon nanotubes produced by solar energy

International audienceBoth single-walled and multi-walled carbon nanotubes ( SWNTs and MWNTs) are produced using a solar reactor working under nitrogen atmosphere. Samples were studied by transmission electron microscopy ( TEM), Raman spectroscopy and electron energy loss spectroscopy ( EELS). The produced MWNTs exhibit the typical morphologies observed for nitrogen-doped MWNTs synthesized with other methods and EELS measurements point out the presence of substituted nitrogen within the tubes. The doping level is not uniform and the maximum value reaches 11 at.%

Lateral Root Formation in Arabidopsis: A Well-Ordered LRexit

Lateral roots (LRs) are crucial for increasing the surface area of root systems to explore heterogeneous soil environments. Major advances have recently been made in the model plant arabidopsis (Arabidopsis thaliana) to elucidate the cellular basis of LR development and the underlying gene regulatory networks (GRNs) that control the morphogenesis of the new root organ. This has provided a foundation for understanding the sophisticated adaptive mechanisms that regulate how plants pattern their root branching to match the spatial availability of resources such as water and nutrients in their external environment. We review new insights into the molecular, cellular, and environmental regulation of LR development in arabidopsis

Raman characterization of single wall carbon nanotubes prepared by the solar energy route

International audienc