Fig. 5

Curcumenol isomer I content under the high-input fertilizer treatment. Curcumenol isomer I content (mg/g DM) in high-input fertilized rhizome of Curcuma longa L. 35–1 was shown under the effect of in vitro Ca²⁺ × KNO₃ mM interaction when the other factors were set as 6.25 mM PO₄³⁻ and 1.5 mM Mg²⁺. The contour surface and surface plus residual data points appeared on the response surface plot