Fig. 4

Foliar concentration of ABA (A), JA (B), SA (C) and IAA (D) in grapevine ‘Castellana Negra’ plants determined at the end of the trial (75 days after treatment, DAT). Values are presented as means ± standard errors, determined from leaves collected per plant (n = 4 plants per treatment). The treatments were designated as control (CT), NaCl (90 mM), NaCl (90 mM) + Si (10 mM), and NaCl (90 mM) + proline (10 mM). Within each variable, different letters denote significant differences (p < 0.05) as determined by ANOVA and Duncan’s test.