Fig. 7

Correlation analysis between root architecture, chemical composition, photosynthetic characteristics and aroma precursors in flue-cured tobacco at 0–130 mg L− 1 lanthanum nitrate. *, **, *** represent significant correlations at the 0.05, 0.01, 0.001 level, respectively. Pn: net photosynthetic rate, Ci: internal CO2 concentration, Tr: transpiration rate, Gs: stomatal conductance, K/Chlorine: Ratio of total K content to nicotine content, N/Nicotine: Ratio of total N content to nicotine content.