Role of polyamines in adventitious root formation

Adventitious root formation (ARF) is considered an effective mechanism for plant survival under extreme conditions while at the same time is the base of vegetative commercial plant propagation. Scientific research has revealed a plethora of endogenous and exogenous factors related to adventitious rooting formation. Among the factors that have been studied so far, polyamines, a group of small aliphatic amines, seem to have a distinctive role. Except for their general physiological role in morphogenic processes, polyamines are related to adventitious rooting and can interact with other plant growth regulators regulating rooting response. Furthermore, their metabolism and its products seem to have a significant role in the rhizogenesis process, whereas exogenous polyamine application can also affect the rooting potential as well, depending on the genotype. In the present chapter, the possible biochemical and physiological role of polyamines in adventitious root formation is discussed, along with some of the elements of their metabolism, physiological roles, and functions. Moreover, the effect of exogenous polyamines’ application on several species is also presented.