Accumulation of organic solutes and enzymatic activity in cut roses (Rosaceae) cultivated with physiological effect products in the Sub- Middle São Francisco River Valley

ABSTRACT: The aim of the present study was to evaluate the accumulation of carbohydrates, protein, and proline as well as the activity of the antioxidant enzymes superoxide dismutase and catalase in the Ambiance cultivar of cut rose plants grown with the application of physiological effect products in the Sub-Middle São Francisco River Valley in Brazil. The experiment was performed under a mesh screen with 50% shading. The experimental design used randomized blocks with four repetitions and six treatments: T1) control (water); T2) boscalid; T3) pyraclostrobin; T4) boscalid + pyraclostrobin (T2 + T3); T5) fluxapyroxad + pyraclostrobin; T6) plant growth regulators 4-(indol-3-yl) butyric acid (IBA) + gibberellic acid (GA3) + kinetin; these treatments were applied every 15 days throughout the crop cycle. To determine the accumulation of solutes and enzymatic activity, 8 leaves was collected every 48 h. Leaves were immediately immersed in liquid nitrogen and frozen until further analysis in the laboratory. Results showed that the product combinations boscalid + pyraclostrobin and fluxapyroxad + pyraclostrobin as well as the plant growth regulators were the treatments with the most consistent responses throughout the evaluated cycle, providing a greater accumulation of solutes in rose leaves, as an osmotic adjustment strategy against stress from high temperatures, particularly when proline accumulation is observed. With regard to enzymatic activity, plant regulators showed more consistent results when compared with other treatments, increasing both superoxide dismutase and catalase activity. The marked accumulation of organic solutes and the high enzymatic activity, particularly of catalase, indicated that rose plants use such mechanisms as a defense against the region’s high temperatures.