Effects of Al and B interactions on root (A), shoot (B) and root + shoot (C) DW, and shoot/root ratio (D) of Citrus grandis seedlings. Diagonal cross area quantifies the Al effect under different B supply. Each point is mean of 8 – 15 replicates with standard error. Difference among eight treatments was analyzed by 2 (Al levels) × 4 (B levels) ANOVA. (A) P values for Al, B, and the interaction between the two were < 0.0001, < 0.0001 and 0.3905; (B), (C), and (D) P values for Al, B, and the interaction between the two were all < 0.0001. Different letters indicate significant differences among eight treatments at P < 0.05.