1. Changes in the definition and legal status of biostimulants

There are still several definitions of a biostimulant, as there is no definition of the phenomenon of biostimulation; only biostimulant products are defined. It is interesting to note the evolution of the definitions proposed, as it demonstrates the complexity of the phenomena and mechanisms that can contribute to plant growth stimulation.

Based on du Jardin (2015 ), the term biostimulant was first defined by Kauffman et al. (2007