Catabolism of putrescine and spermidine in embryogenic and non-embryogenic callus lines of Picea abies

The oxidation of putrescine and spermidine were studied in embryogenic and nonembryogenic cell cultures of Picea abies (L.) Karst., with 1,4-¹⁴C]-putrescine and 1,4-¹⁴C]-spermidine as substrates. Activities of putrescine and spermidine oxidation varied at every developmental stage in both cultures. Putrescine was oxidized ca 5 times as fast both in embryogenic and non-embryogenic tissue as spermidine. Diamine and especially polyamine oxidase activity increased markedly in both tissues towards the end of the culturing. In maturing embryos and in ageing non-embryogenic cultures, enzyme activities were lower than in non-differentiated embryogenic calli. Aminoguanidine (1 m M ) inhibited di- and polyamine oxidation in non-embryogenic tissue by >60% and >30%, respectively. The pH optimum for putrescine oxidation was 8.0, but in non-embryogenic tissue spermidine was degraded even more actively at pH 5.0. ¹⁴C]-Spermidine was catabolized to ¹⁴C]-putrescine. Pyrroline dehydrogenase activity was observed in non-embryogenic spruce tissue cultures.