Oxidative stress and antioxidant responses in olive tree subjected to cover crops under rainfed conditions

Since Mediterranean basin is particularly vulnerable to present and future climate variability and climate change, olive tree will experiment some hard changes in its environment. Under adverse conditions, imbalances in metabolic processes may lead to increased accumulation of ROS, forming a potential threat of oxidative damage to cells. We propose green manure legumes to shift tillage, in order to improve soil water relationships during the drought period. The research was carried out in northeast Portugal under rainfed conditions. The treatments laid out were: ordinary tillage techniques and a mixture of eleven annual (AL) pasture self-reseeding legumes. The results obtained in summer 2011 revealed that olive in AL plot had higher concentrations of chlorophylls, carotenoids and total thiols, as well stomatal conductance, net photosynthesis, qP, FvN/FmN, quantum yield of PSII, ETR and APX activity. Conversely, olive trees subjected to tillage had higher qN and GST activity. No significant differences were reported in electrolyte leakage, CAT activity and in TBARS and total phenols concentration. Thus, legume species may be a promising strategy contributing to the sustainable management of olive orchards