Fig. 1

Polyamine biosynthetic pathway. Pathway for the biosynthesis of polyamines in Arabidopsis thaliana; abbreviations: ODC, ornithine decarboxylase (absent in Arabidopsis); ADC, Arginine decarboxylase; SAMDC, S-adenosylmethionine decarboxylase; SPDS, spermidine synthase; SPMS, spermine synthase; tSPMS, thermospermine synthase