POLYAMINES IN CELL DIVISION, FRUIT SET AND DEVELOPMENT, AND SEED GERMINATION

The activity of polyamines as growth promoters was first shown in bacteria and yeasts in the pioneering work of Tabor and Tabor in the 1950s. ¹ Research on this subject was extended to animals, ² in which high levels of endogenous polyamines were found, and to plants. ^{3, 4} Later, the possibility that polyamines also play a role in cell division in plants was raised. The effect of external polyamines in inhibiting senescence of oat protoplasts and enhancing incorporation of radioactive precursors [³H]-uridine and [³H]-leucine into RNA and proteins suggested an antisenescence or growth-promoting action for polyamines in plants. ^5-7 The role of polyamines in cell division in plants has been studied in a wide range of systems, such as protoplasts cultured in vitro, ^{5, 6, 8, 9} fruit set and development (see below), intermodal growth, ^10-12 and algae. ^13-16.