Polyamine, ethylene and other physico-chemical parameters in tomato (Lycopersicon esculentum) fruits as affected by salinity

Tomato plants (Lycopersicon esculentum Mill. cv, Daniela) mere grown in per lite bags under greenhouse conditions to study the effect of different sali nity levels (20, 40 and 60 mM NaCl) on fruit fresh weight, firmness, color, ethylene production. total 1-aminocyclopropane-1-carboxylic acid (ACC) and polyamine levels. Saline treatments mere applied at different times: at th e beginning of the plant grow th period, and at the developmental stages of flowering of the first cluster and fruit growth of first cluster, Salinity , in general, increased fruit firmness, the intensity of red color, total A CC and ethylene production, while decreasing the final fruit weight. Polyam ine levels (spermidine and putrescine) were also increased with salinity, e specially when it was applied at the fruit growth of first cluster stage. T he relationship between fruit firmness and elevated polyamine content as a result of saline stress is discussed.