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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, H 2 O 2 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 H 2 O 2 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 H 2 O 2 generation.

The coastal vegetation at Cap Bon (Tunisia) began to decay in the 80s. Our work describes the symptoms, the extent of the phenomenon in Tunisia and classifies a number of acclimatised species according to their sensitivity to sea spray. Acacia cyanophylla Lindl. and Eucalyptus gomphocephala Dc. branches and twigs which are exposed to sea spray exhibit characteristic symptoms that are not attributable to parasite attacks or to solely to sodium chloride. We suggest that domestic detergents that are found in concentrated form in spray cause this dieback, La végétation côtière du Cap Bon (Tunisie) a présenté, à partir des années 1980, un dépérissement. Notre travail en décrit les symptômes, présente l'ampleur du phénomène en Tunisie et classe certaines essences acclimatées selon leur sensibilité aux embruns marins. Les branches et les rameaux d'Acacia cyanophylla Lindl. et d'Eucalyptus gomphocephala Dc. qui sont exposés aux embruns marins présentent des symptômes caractéristiques qui ne sont pas imputables à des attaques parasitaires ou à l'effet unique du chlorure de sodium. Nous suggérons que ce phénomène de dépérissement est causé par les détergents domestiques qui se retrouvent sous forme concentrée dans les embruns