FREE POLYAMINE CONTENT IN LEAVES AND BUDS OF HAZELNUT (CORYLUS-AVELLANA L. CV NEGRET) TREES SUBJECTED TO REPEATED SEVERE PRUNING

The effect of repeated severe pruning on endogenous free polyamine con tent in leaves and buds of adult hazel (Corylus avellana L., cv. Negre t) was studied. Polyamine levels varied in relation to pruning intensi ty, indicating that a reinvigorating phenomenon was taking place. The putrescine to spermidine plus spermine ratio increased significantly i n relation to pruning, supporting the view that the metabolic dynamic of polyamines, more than the individual concentrations of any one of t hem, may participate in the control of plant ontogeny and the derived morphogenic potential. Differences in the polyamine content were obser ved in the studied hazel cv. Negret in comparison with previously publ ished data on another hazel cultivar ('Gironell'), that can be related to the different morphogenic potential of both cultivars. This may in dicate that genotypic differences affect both polyamine biosynthesis a nd metabolism as well as morphogenic expression, taking into account t he genetic complexity of these processes. (C) 1998 Elsevier Science B. V. All rights reserved.