Fig 4. Effects of different priming solutions on antioxidant enzyme activities of rape seedlings under low temperature and drought conditions.

Effects of low temperature and drought stressed (25°C and 0 MPa, 15°C and -0.15 MPa) on antioxidant enzyme activity with (A) superoxide dismutase (SOD), (B) catalase (CAT), (C) peroxidase (POD), and (D) ascorbate peroxidase (APX) in Brassica napus seedlings (varieties ZY15 and HY49). Seven different treatments were evaluated: (a) control (Ck), (b) water (H₂O), (c) salicylic acid (SA), (d) gibberellic acid (GA), (e) sodium nitroprusside (SNP), (f) calcium chloride (CaCl₂), and (g) abscisic acid (ABA). Each point represents the mean of three replicates. The values presented are the mean ± standard deviation (SD). Significant differences among treatments were determined by a three-way analysis of variance (ANOVA) (p < 0.05 according to Duncan’s multiple range tests).