Review: Long-term research activity on the biostimulant properties of natural origin compounds

For ten years the Department of Agricultural Biotechnology, University of Padua, supported by the company ILSA SpA, Arzignano, (VI), Italy, has been studying, via different methodologies, the biostimulant properties of products derived from different organic raw materials. The research activity includes the development of specific bioassays designed for understanding the biological activity of the various compounds and the evaluation of their effects on maize metabolism, grown under controlled conditions. Plants treated with these products confirmed their biological activity in terms of capacity to increase plant growth and stimulate plant nitrogen and carbon metabolisms. In addition, the effects of phenol-containing organic substances derived from agro-industrial byproducts were assayed on phenylpropanoid metabolism. Phenol-containing products, in particular, increased plant antioxidants, key elements for human health. The products also increased plant biomass, exerted a positive role on nitrogen metabolism and stimulated the activity and gene expression of phenylalanine ammonia-lyase, the first enzyme of the phenylpropanoid pathway. Our results indicate that biostimulants can be used as bioactive products in agriculture to increase plant yield and resistance to stress conditions.