ENDOGENOUS POLYAMINE CONCENTRATIONS IN JUVENILE, ADULT AND IN-VITRO REINVIGORATED HAZEL

We investigated endogenous polyamine concentrations in leaves from juv enile and mature hazel (Corylus avellana L.) shoots, as well as leaves from shoots obtained by both forced outgrowth and micropropagation of adult tissues. To determine if the observed in vitro reinvigoration w as associated with polyamine metabolism, we tested the effect of seria l subcultures on polyamine concentrations. Polyamines, mostly free put rescine, were higher in juvenile tissues. Adult tissues micropropagate d for 14 subcultures had polyamine concentrations characteristic of ju venile tissues. However, with additional subcultures, total polyamine concentrations decreased. The putrescine to spermidine plus spermine r atio was higher in juvenile and micropropagated tissues than in adult tissues, but decreased in micropropagated tissues after 20 subcultures . This ratio may reflect a balance between vegetative growth and repro ductive processes. Thus, an analysis of polyamine concentrations may p rovide a simple assay for determining the juvenility of plant tissues and, hence, their suitability for micropropagation.