Fig 4.

The modification in the concentration of leaf K [a], fruit K [b], leaf Fe [c], fruit Fe [d], leaf Zn [e], and fruit Zn [f] in response to the long-time foliar application of BZnO and ZnO-NP at a low dose. Different letters on top of columns refer to statistically significant differences according to Tukey’s multiple comparisons test. ns: non-significant; *: 0.01<p≤0.05; **: 0.001<p≤0.01; ***: 0.0001<p≤0.001; ****: p≤0.0001. The p-value levels for comparing the mean of each group vs the control group are displayed by the asterisk on each column. Also, an asterisk [*] on the drawn lines presents the p-value levels for comparison between the BZnO and ZnONP groups.