Investigating organic molecules responsible of auxin-like activity of humic acid fraction extracted from vermicompost

Autor(es)

Scaglia, Barbara ^[1] ; Nunes, Ramom Rachide ^[2] ; Oliveira Rezende, Maria Olimpia ^[2] ; Tambone, Fulvia ^[1] ; Adani, Fabrizio ^[1]

Afiliação do(s) autor(es)

^[1] Univ Milan, Grp Ricicla Labs DiSAA, Via Celoria 2, I-20122 Milan - Italy

^[2] Univ Sao Paulo, Lab Quim Ambiental, Inst Quim Sao Carlos, Ave Trabalhador Sao Carlense 400, Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Science of The Total Environment; v. 562, p. 289-295, AUG 15 2016.
• Citações Web of Science: 19

Resumo

This work studied the auxin-like activity of humic acids (HA) obtained from vermicomposts produced using leather wastes plus cattle dung at different maturation stages (fresh, stable and mature). Bioassays were performed by testing HA concentrations in the range of 100-6000 mg carbon L-1. C-13 CPMAS-NMR and GC-MS instrumental methods were used to assess the effect of biological processes and starting organic mixtures on HA composition. Not all HAs showed IAA-like activity and in general, IAA-like activity increased with the length of the vermicomposting process. The presence of leather wastes was not necessary to produce the auxin-like activity of HA, since HA extracted from a mix of cattle manure and sawdust, where no leather waste was added, showed IAA-like activity as well. CPMAS (CNMR)-C-13 revealed that HAs were similar independently of the mix used and that the humification process involved the increasing concentration of pre-existing alkali soluble fractions in the biomass. GC/MS allowed the identification of the molecules involved in IAA-like effects: carboxylic acids and amino acids. The concentration of active molecules, rather than their simple presence in HA, determined the bio-stimulating effect, and a good linear regression between auxin-like activity and active stimulating molecules concentration was found (R-2 = -0.85; p < 0.01, n = 6). (C) 2016 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 14/05041-0 - Estudo espectroscópico da dinâmica da vermicompostagem de resíduos da indústria de couro (curtumes) para produção de plantas de interesse econômico
• Beneficiário: Ramom Rachide Nunes
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado