SEASONAL FLUCTUATIONS IN FREE POLYAMINES IN SCOTS PINE NEEDLES

Seasonal fluctuations in the free polyamines putrescine, spermidine and spermine were monitored in the needles of six specimens of Scots pine (Pinus sylvestris L.) in Central Finland from March, 1991 to December, 1992. Putrescine was the major polyamine in the needles and spermine occurred in the lowest concentrations. Current year needles showed higher polyamine levels than current + 1 year needles. The highest putrescine values were measured in winter and lowest in summer, but considerable variations were observed between the trees in winter. Spermidine concentrations were highest in spring. Low spermidine values were observed in most trees usually in December, but also in April and August. Spermidine did not show as regular a fluctuation as did putrescine. Low spermine values coincided with low temperatures in winter, and spermine increased during April and May in both years. The ratio putrescine/spermidine in the needles showed less variation between the trees than the absolute polyamine levels. Increase in put/spd ratio was observed in December, 1991, between March and May, 1992 and October, 1992.