Figure 1. Effects of saline stress on the relative growth rate (RGR) of the silver maple seedlings exposed to different salinity levels (NaCl or CaCl₂) after 180 (A, C) and 360 (B, D) days (g g⁻¹ FW d⁻¹).

Values are mean ± SD (n = 4). Different numbers above each bar indicate significant differences by ANOVA followed by Tukey’s test at P < 0.05.