Differential responses of two maize (Zea mays L.) varieties to salt stress: Changes on polyphenols composition of foliage and oxidative damages

The leaf-structural adaptative strategies and the possible involvement of the antioxidative system in the tolerance to salt stress were investigated in relation to leaf tissue senescence of maize. Studies were carried out with seedlings of two forage maize varieties (Aristo and Arper) subjected to 0, 34, 68 and 102 mM NaCl for 6 weeks under glasshouse conditions. The leaf growth, leaf water content, H2O2 generation, lipid peroxidation, membranes stability index and polyphenolic compounds (total polyphenols, total flavonoids, anthocyanins and proanthocyanidins) accumulation were quantified in three leaf stages (young, mature and senescent leaves). Salt stress impacts in term of H2O2 generation and lipid peroxidation were more pronounced in senescent leaves. During the stress treatment, the accumulation of the major polyphenolic compounds was higher in young leaves. A significant variability in salt response was found between both varieties. The better behaviour of Arper salt-challenged leaves compared to those of Aristo may be related to their higher water content and polyphenol accumulation mainly anthocyanins which showed to participate efficiently in restriction of oxidative damages caused by the H2O2 generation.