Crescimento foliar e atividades das enzimas antioxidativas em plântulas de girassol suplementadas com percolado de aterro sanitário e submetidas a estresse hídrico

Abstract

In arid or semi-arid regions, the limited availability of water resources has been one the main limiting factors in agricultural production. We analyzed the effects of the application of sanitary landfill leachate on the growth of leaves (number of leaves and leaf area) and the activities of the antioxidative enzymes superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) in the leaves and roots of sunflower seedling subjected to drought stress. The experimental design was completely randomized in a factorial two (irrigated and non-irrigated) x four (sand; sand + organic fertilizer 100 kg N ha-1; sand + sanitary landfill leachate 100 kg N ha-1; sand + sanitary landfill leachate 150 kg N ha-1) with five replicates. In relation to foliar growth, the treatment 100 kg N ha-1 supplemented by sanitary landfill leachate increased the number of leaves and leaf area. In addition, there were increases in the antioxidative enzymes’ activities in leaves and roots of sunflower seedlings supplemented by sanitary landfill leachate. Thus, it is possible that the reductions in harmful effects of drought stress on the leaves’ growth in treatments supplemented by sanitary landfill leachate occurred due to increased antioxidative enzymes activities, especially Cat in leaves and Gpx in roots.