COMPARISON OF ENDOGENOUS POLYAMINE CONTENT IN HAZEL LEAVES AND BUDS BETWEEN THE ANNUAL DORMANCY AND FLOWERING PHASES OF GROWTH

Variations of endogenous polyamine levels were determined in leaves an d buds of mature hazelnut trees (Corylus avellana). Results indicated specific correlations between high spermidine and spermine levels with rapid shoot growth and leaf expansion. Conversely, low spermidine and spermine, along with increasing putrescine levels, may be associated with the imposition of shoot-bud dormancy. In previous studies on the morphogenic ability in hazel, and taking into account that hazel expla nts can be easily established in vitro during dormancy imposition, we observed that high levels of putrescine and increasing putrescine to p olyamines ratios could be related to a higher morphogenic potential in this species, showing in adult tissues the typical behaviour of juven ile tissues in vitro. Genotypic differences affecting the morphogenic potential could account for the observed differences in the polyamine levels of the cultivars. The data obtained could also be correlated wi th seasonal changes of other endogenous growth regulators in hazel.