title: Structure-Property-Function Relationship in Humic Substances to Explain the Biological Activity in Plants.
abstract: Knowledge of the structure-property-function relationship of humic substances (HSs) is key for understanding their role in soil. Despite progress, studies on this topic are still under discussion. We analyzed 37 humic fractions with respect to their isotopic composition, structural characteristics, and properties responsible for stimulating plant root parameters. We showed that regardless of the source of origin of the carbon (C3 or C4), soil-extracted HSs and humic acids (HAs) are structurally similar to each other. The more labile and functionalized HS fraction is responsible for root emission, whereas the more recalcitrant and less functionalized HA fraction is related to root growth. Labile structures promote root stimulation at lower concentrations, while recalcitrant structures require higher concentrations to promote a similar stimulus. These findings show that lability and recalcitrance, which are derived properties of humic fractions, are related to the type and intensity of their bioactivity. In summary, the comparison of humic fractions allowed a better understanding of the relationship between the source of origin of plant carbon and the structure, properties, and type and intensity of the bioactivity of HSs in plants. In this study, scientific concepts are unified and the basis for the agronomic use of HSs is established.
authors: Federal Rural University of Rio de Janeiro, Soil Science Dept. Rodovia BR 465 km 7, Seropédica, RJ, CEP 23890-000, Brazil.
authors: Andrés Calderín
authors: AC
authors: García
authors: Federal Rural University of Rio de Janeiro, Soil Science Dept. Rodovia BR 465 km 7, Seropédica, RJ, CEP 23890-000, Brazil.
authors: Luiz Gilberto Ambrosio
authors: LG
authors: de Souza
authors: Federal Rural University of Rio de Janeiro, Soil Science Dept. Rodovia BR 465 km 7, Seropédica, RJ, CEP 23890-000, Brazil.
authors: Marcos Gervasio
authors: MG
authors: Pereira
authors: Federal Rural University of Rio de Janeiro, Chemistry Department, Rodovia BR 465 km 7, Seropédica, RJ, CEP 23890-000, Brazil.
authors: Rosane Nora
authors: RN
authors: Castro
authors: Department of Environmental Biology, Agricultural Chemistry and Biology Group-CMI Roullier, Faculty of Sciences, University of Navarra, Pamplona, Navarra 31008, Spain.
authors: José María
authors: JM
authors: García-Mina
authors: Federal Rural University of Rio de Janeiro, Soil Science Dept. Rodovia BR 465 km 7, Seropédica, RJ, CEP 23890-000, Brazil.
authors: Everaldo
authors: E
authors: Zonta
authors: Federal Rural University of Rio de Janeiro, Soil Science Dept. Rodovia BR 465 km 7, Seropédica, RJ, CEP 23890-000, Brazil.
authors: Francy Junior Gonçalves
authors: FJ
authors: Lisboa
authors: Federal Rural University of Rio de Janeiro, Soil Science Dept. Rodovia BR 465 km 7, Seropédica, RJ, CEP 23890-000, Brazil.
authors: Ricardo Luis Louro
authors: RL
authors: Berbara
mesh_terms: D006812:Humic Substances; D063245:Plant Development / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects* / Q000378:metabolism*; D013329:Structure-Activity Relationship
chemical_list: D006812:Humic Substances