Tea-leaf quality depends strongly on its chemical composition, which is influenced by both environmental metal availability and internal elemental redistribution. Under acidic growing conditions, iron (Fe) and aluminum (Al) frequently coexist at elevated levels and may jointly affect leaf chemical architecture and quality-related traits. In a factorial Fe × Al hydroponic experiment, we quantified cross-organ partitioning using elemental concentrations, translocation factors, and whole-plant partitioning metrics, and characterized leaf organic matrix composition by FTIR-derived indices for proteinaceous, aromatic, lipid, and polysaccharide domains. Multivariate and path analyses indicated that Fe Al interactions altered root ionic competition and long-distance metal mobility, consistently coinciding with leaf matrix shifts. Protein-to-polysaccharide, aromatic-to-polysaccharide, and oxidation indices strongly tracked Fe- and Al-related metrics and were more closely associated with polyphenols, free amino acids, and chlorophyll index than individual elemental concentrations. This study demonstrates the utility of FTIR-based chemical profiling combined with chemometric analysis for linking metal-driven elemental redistribution to quality formation in tea leaves. • Coordinated Fe Al supply reshapes metal translocation across root, stem, and leaf. • Ion-ratio–mediated Fe Al interactions regulate long-distance metal transport. • Leaf organic matrix remodeling revealed by FTIR functional group indices. • Metal-driven matrix remodeling provides chemical links to tea quality traits.
Li et al. (Wed,) studied this question.