Composition chimique de sèves xylémiques du genre Lycopersicon (Solanaceae) en relation avec l'environnement. II. Effet de la salinité

Two tomato species, Lycopersicon esculentum Mill. var. Edkawy and Lycopersicon cheesmanii (Hook) C. H. Mull, ecotype LA 1138, were grown in saline (100 mM NaCl) conditions. The study of weight increase of these two species showed that L. cheesmanii was the least affected by salinity. The chemical composition of xylem sap (cations, anions, amino acids) was analysed by high performance liquid chromatography. This study demonstrated a control of NaCl transport in L. esculentum, but not in L. cheesmanii. Moreover, ammonium appeared in xylem sap of L. cheesmanii in saline culture. Different hypotheses about its origin are discussed. Key words: ammonium, salinity, xylem sap, Lycopersicon.