Fig. 1
Effects of nitrogen levels on N uptake, use and N metabolism-related enzymes activity in Panax notoginseng. A TN is the total N uptake (mg·plant-1), TNL is the total N uptake per unit root length (mg·cm-1), RNL is the root N content per unit root length (mg·cm-1); B Proportion of N distribution to shoot and root (%); C Harvest index, N harvest index, NUEb is N use efficiency in biomass production (g·DW g-1·N), N uptake efficiency (kg·kg-1), NUE is the N use efficiency (kg·kg-1); D Nitrite reductase (NiR, μmol·h-1·g-1 FW), glutamine synthetase (GS, U·g-1 FW), glutamate synthetase (GOGAT, nmol Glu·min-1·g-1 FW), glutamate dehydrogenase (GDH, nmol·min-1·g-1 FW). Green represents N0, blue represents N7.5, red represents N15. Values for each point were means ± SD (n = 3). Significant differences are indicated by letters (ANOVA; P < 0.05)