Abstract
In this study, 61 xylem tissue samples of Larix sibirica (Siberian larch) were collected from Hami, Xinjiang, and employed as experimental materials. An untargeted metabolomic approach based on ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was utilized to characterize metabolic profiles across tree samples with distinct chronological gradients. All tree core samples were categorized into seven decade-based groups (B50s, B60s, B70s, B80s, B90s, B00s, and B10s) according to their growth initiation years. A total of 2280 metabolites were successfully identified in the obtained datasets. Principal component analysis (PCA) exhibited obvious inter-group separation in score plots, indicative of systematic metabolic variations in Larix sibirica xylem along the chronological gradient. Differential metabolite enrichment analysis demonstrated that multiple core pathways were significantly altered across groups, including starch and sucrose metabolism, flavonoid biosynthesis, glycerophospholipid metabolism, and amino acid metabolism. Based on Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation and functional enrichment analysis, we further elucidated the correlations between metabolite accumulation patterns and tree chronological age, as well as drought stress responses. This study provides fundamental empirical data for clarifying the temporal evolutionary characteristics of the larch wood metabolome and unveiling the molecular mechanisms underlying its environmental stress adaptation.