Fig. 4

Effects of different concentration of chitosan nanoparticles (CNPs) (30, 60 and 90 ppm) on proline and protein content in leaves of S. abrotanoides in responses to drought stress levels (30, 50, and 100% FC). Values are means ± SD (n = 4). According to Duncan’s Multiple Range Test, different bar letters indicate significant differences among treatments (P ≤ 0.05)