Avaliação da atividade das enzimas catalase e superóxido desmutase em plântulas de amburana cearensis

Resumo

The plants are sessile organisms and needs to develop mechanisms to adapt to their environment and the changes that it suffers. Among the many factors that can cause stress to plants is water restriction. The decrease in water availability may cause problems since the beginning of plant life, limiting or preventing the germination but also may cause problems for seedling establishment, limiting their growth and development. The plants have production and detoxification of reactive oxygen species that are in equilibrium systems, but in situations of abiotic stress, they produce the ERO in greater quantities than their ability to consume them, causing oxidative stress. The ability to respond to oxidative stress is one of the important features that makes a plant present resistance to abiotic stresses. The species Amburana cearensis shows resistance to water restriction, which justifies be used in this study. The aim of this study was to evaluate the activity of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in seedlings of A. cearensis. A. seeds cearensis were scarified and subjected to germination at 30°C with constant light. After the appearance of the third pair of leaves, the seedlings were separated into roots and shoots, soaked in liquid N2 and stored at -20°C. Total proteins were extracted in appropriate buffer, assayed by Bradford method, enzyme activity CAT was measured spectrophotometrically following the decomposition of hydrogen peroxide and SOD enzyme activity was measured also by spectrophotometry, using the methodology of reduced NBT. It was possible to verify that the levels of total protein and SOD activity were higher in shoots than in the roots, which is expected, considering that the ERO are produced in larger quantities in photosynthetic plant tissues. It is concluded that the species A. cearensis is able to germinate successfully in vitro and has active antioxidant defense enzymes in their aerial parts. More experiments are needed to characterize the antioxidant defense system of this kind.