Supplementary Data – Alpinia chinensis essential oils

We evaluated essential oils (EOs) obtained separately from the rhizome, leaf, fruit, stem and flower of Alpinia chinensis (Retz.) Roscoe. GC–MS identified 74 volatile constituents representing 96.07–97.63% of each oil and revealed pronounced organ-specific chemical differentiation.

Phytotoxicity was quantified at 0–1.60 µL mL⁻¹ against two cultivated rice genotypes (OM18 and RVT), weedy rice, Echinochloa crus-galli, E. colona and Leptochloa chinensis. Factorial inference based on raw dish-mean seedling lengths showed highly significant effects of dose, EO source organ and their interaction for every weed response (all P < 0.001; partial η² = 0.812–1.000). L. chinensis was exceptionally sensitive: leaf EO caused 100% shoot and root inhibition at 1.60 µL mL⁻¹, while ED₅₀ estimates within the tested range were 0.189–0.412 µL mL⁻¹ for shoots and 0.094–0.433 µL mL⁻¹ for roots.