Anatomicals traits at stem level of sorghum could you help optimize the selection of performing genotypes targeted to biomass applications

The presence and structure of lignins have an important impact on the quality of a wide range of different plant-based resources. The mechanical and degradability properties of the different tissues of the plant material largely depends on the lignification of the cell walls, the histological features such as the cellular morphology or the relative amount of each tissue fraction, the composition and the spatial distribution of tissues within plant organs. Many studies, in particular devoted to increase the degradability of plant cell walls, showed a wide range of techniques for studying lignin and polysaccharides. By combining staining, microscopic methodologies and imagery we reached a high level of cellular resolution. Large scale studies of anatomical features (Zhang et al. (2013), Legland et al. (2017), El Hage (2018)) on maize showed links between anatomical traits in stalk and the detection of candidate genes, the biomass stalk anatomical traits and the biochemical or physical properties of the biomass and led to the identification of candidate genes. Recent studies on sorghum mobilized quantitative anatomical internode analysis to better understand response to water availability (Perrier et al. (2017), Luquet et al. (2018)) and biogas production (Thomas et al. 2021). However most of these studies focused on a single internode level of the stem. In this presentation we highlight the intra stem variability of a set of morphological, anatomical and biochemical traits analyzed in successive elongated internodes along the stem of two contrasted genotypes for composition and hydrolysis yield over 3 years. Two approaches of anatomical studies are presented: colorimetric information and multispectral autofluorescence imaging to focus on phenolic compounds.