Figure 3.

Effect of foliar spray by glycine betaine (GB), chitosan (CHT) and combination (Co) on photosynthetic pigments (A–C) and malondialdehyde (MDA) (D) content in leaves of cucumber plant under absolute control (AC) and CMV infection (challenge control, ChC) after 21 days of inoculation. Means with the different letters (a, b, c, d, e, f, g) are significantly different at the 0.05 level among treatments according to Tukey’s test. Vertical bars represent means of three independent determinations ± standard error (SE). *, ** and ns indicate significant, highly significant and ns, statistically insignificant difference according to two-way ANOVA with Tukey’s post hoc test.