Changes in maximal activities of the chloroplastic glutathione reductase and cellular catalase.

<p>Values for antioxidant enzyme glutathione reductase (GR) (left), as well as for cellular catalase (CAT) (right), along the entire experiment for Apoatã (Ap), Icatu (Ic), and Obatã (Ob) genotypes, under well-watered (WW), mild drought (MD) and severe drought (SD) conditions, and submitted to temperature control conditions (25/20 ^oC), during the gradual temperature decrease (18/13 ^oC), at the end of the acclimation period (13/8 ^oC), after 3 chilling cycles (3x13/4 ^oC), after 7 days under rewarming conditions (7x Rec Cold), and after a further 7 days period under rewatering conditions (7x Rec Drought). For each enzyme, the mean activity values ± SE (n = 4) followed by different letters express significant differences between temperature treatments for the same water availability level (a, b, c, d, e, f), or between water treatments for each temperature treatment (A, B, C), always separately for each genotype.