The 46-year long scientific career and the main research topics of Nello Bagni, one of the pioneers in plant polyamine studies, are reviewed by his past students and collaborators. The main topics summarized here are: the polyamine metabolic pathway; interactions of polyamines with macromolecules; polyamine translocation, uptake and compartmentation; the Helianthus tuberosus plant model system; polyamines and morphogenesis; polyamines and higher plant reproduction, stress and pathogen responses; environmental pollution; polyamines and food; historical studies. Other minor aspects of his work not cited in the text are reported in the full list of publications.