Wood (secondary xylem) is a valuable resource for the generation of renewable energy and it is an important feedstock for fiber, pulp and cellulose production. The process of wood formation is strongly affected by environmental conditions such as water, nutrient and light availability. Despite the importance of secondary growth to trees, the metabolic profile underlying wood formation still poorly understood. Here, we present a metabolomics approach (GC-TOF-MS and LC-QTOF-MS) performed to identify both (a) the metabolic distribution from phloem towards wood-forming tissues, (b) key metabolites with specific roles during wood formation. To this purpose, hybrid aspen (Populus tremula x P. tremuloides) trees were cultivated under greenhouse conditions and supplied four different levels of nitrogen, to obtain trees with different secondary growth. The stems from four-month-old trees were cryo-sectioned (20 µm) in: bark, inner bark, phloem, expanding phloem, cambium, expanding xylem, xylem, mature xylem and pith. Trees treated with high nitrogen concentration showed higher diameter, height and biomass, compared to the others treatments. By multivariate analysis, we could discriminate tissues and treatments. A gradient of metabolites belonging to different chemical classes (sugars, amino acids, phenolics) was identified along the differentiated wood tissue and towards phloem. The results obtained here represent the metabolic overview of secondary growth and highlighted the powerful combination of cryosectioning and metabolomics analysis in forestry research
No datasets are available for this submission.