Fig. 7 reveals that leaf Na+ and K+ concentrations and Na+/K+
ratio were significantly affected by biochar, salinity as well as their
interactions. Leaf Na+ concentration and Na+/K+ ratio increased
while leaf K+ concentration decreased at S1 compared to S0. Compared
to the non-biochar control, biochar addition reduced Na+
concentration but increased K+ concentration thus lowered Na+/K+
ratio in the leaf at S1; however, at S0 no significant difference
was found. Moreover, significant positive correlation was found
between leaf Na+ concentration and [ABA]leaf (Fig. 8).