Biological activity of different botanical extracts as evaluated by means of an array of in vitro and in vivo bioassays

Recently, increasing interest has been paid to the biostimulant properties of plant extracts as they have been shown to improve crop yield and quality. Biolchim SpA is a leading company in the production and commercialization of biostimulants. The working approach to the development of innovative products is focused on the research of plant extracts with biostimulant properties. To this aim, Biolchim SpA has created a collection of botanical extracts whose potential use as biostimulants has to be screened according to their biological activity. Bioassays are small-scale tests that assess the biological activity of substances by evaluating their effect on living model organisms. In this study, an array of in vitro (root-tip elongation test) and in vivo (greenhouse growth tests) bioassays was set up and used to test the biostimulant properties of two botanical extracts. Overall results indicate that the array of bioassays is able to screen and differentiate the extracts according to their biological activity. The root-tip elongation bioassay is a first and rapid screening method of their hormone-like properties; the greenhouse growth bioassays provide information on their biostimulant performances in growth conditions similar to the open field and on their possible mode of application. The array of bioassays will be improved by including further in vitro and in vivo tests to fully unravel the biological properties of the extracts. The final goal is to screen the whole collection and classify the extracts according to their potential use as biostimulants. After the screening, prototypes will be formulated by combining different extracts and their efficacy will be tested in open field conditions.