Nitrogen is the most important element for higher plants, and plant productivity is to a large extend determined by nitrogen nutrition. Effects of nitrogen nutrition on levels of polyamines in leaves and grappes of two vines (Semillon and Sauvignon) are studied at different stages of their development (flowering, fruit set process, veraison and maturity). Two N-fertilizations are compared : N0 (0 kgN/ha/year) and N90 (90 kgN/ha/year). Analysis concerned the total level of nitrogen and polyamines (free and conjugates). Polyamines (putrescine, spermidine, spermine and diaminopropane) were derived by dansylation and analysed by CLHP. The results show that N-nutrition induces major changes in the total level of nitrogen and polyamines in various parts of plants. In all organs, excess of N-nutrition increases the total level of nitrogen. Concerning polyamines, these changes differe according to tissue and stage of development. In flowers and green berries, N-excess increases free polyamines whereas in berries during maturation N-excess increases total level of polyamines and particularly free and wall-bound polyamines. In opposite, in leaves, total level of polyamines increases under N-deficiency. These results reflect different rates of metabolism of polyamines between tissues. They suggest that in berries a restricted polyamines synthesis induced by nitrogen deficiency; whereas in leaves, N-deprivation can induce an accumulation of putrescine as do many others stress. The roles of polyamines in berries and in leaves are discussed.
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