Floral induction in mature,perennial angiosperm fruit trees: Similarities and discrepancies with annual/biennial plants and the involvement of plant hormones

Floral induction (FI) in perennial fruit trees is distinct from that of annual/biennial (a/b) plants because it is a quantitative process with a significant proportion of the above-ground meristems remaining vegetative, while in a/b-plants all the meristems are induced at once, which terminates the life of the plant. Currently, regulatory mechanisms of floral induction in perennial angiosperm trees are inadequately described, particularly with respect to physiological/molecular mechanisms that prevent the partial or total inaccessibility of genes or meristems for reacting to particular floral promoters, one of the most important prerequisites of perenniality. Epigenetic modifications, which have been studied almost exclusively in a/b-plants and not in perennial trees, are a likely possibility for achieving this “perenniality” of trees and are therefore described in some detail in the following review. Due to the lack of research on this phenomenon, the description of this paragraph is largely speculative.