Mecanismos enzimáticos e não enzimáticos em cultivares de couve-flor submetidas a diferentes tipos de telas de sombreamento e épocas de cultivo

Abstract

In this study, enzymatic and non-enzymatic mechanisms were evaluated in cauliflower cultivars submitted to different shading screens and different planting times. The design was used in a 5x3x2 factorial design with 5 screens: Aluminet® 50%, Cromatinet® 35%, sombrite 35%, sombrite 50% and open field; 3 cauliflower cultivars: Verona CMS, Cindy and Sharon; and 2 planting seasons: season 1 (autumn / winter) season 2 (spring / summer) with 3 replicates. The enzymatic mechanisms were evaluated through the activity of catalase, ascorbate peroxidase and superoxide dismutase, and the non-enzymatic ones with the quantification of the total phenol content, ascorbic acid and antioxidant potential by the ABTS and DPPH method. The results showed that the cultivars underwent direct influence of the forms of shading in functions of the growing seasons. The cultivation in season 2 significantly increased the levels of phenols, ascorbic acid and antioxidant potential when compared to the crop in season 2 and that each cultivar presented different responses as a function of the shading screens these factors. As for the enzymatic antioxidant mechanism, enzyme activity was high, except ascorbate peroxidase, in the spring / summer crop. The environment generated by the different seasons and / or the different screens, highlighting the question of the temperature factor, provided this elevation. It is concluded that the genotypes evaluated here do not tolerate the cultivation in season 2 due to the high enzymatic and non-enzymatic activity, which compromises the physiological and biochemical balance of the plant for its development. However, at that time the cauliflower had higher nutritional value.