Fig. 7

Methenolone content under the high-input fertilizer treatment. Methenolone content (mg/g DM) in low-input fertilized rhizome was shown under the effect of in vitro Mg²⁺ × KNO₃ mM interaction when other factors set as 6.25 mM PO₄³⁻, and 6.2 mM Ca²⁺. The contour surface and surface plus residual data points appeared on the response surface plot