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. 2016 Feb 10:6:20798.
doi: 10.1038/srep20798.

Structure-Property-Function Relationship in Humic Substances to Explain the Biological Activity in Plants

Andrés Calderín García  1 , Luiz Gilberto Ambrosio de Souza  1 , Marcos Gervasio Pereira  1 , Rosane Nora Castro  2 , José María García-Mina  3 , Everaldo Zonta  1 , Francy Junior Gonçalves Lisboa  1 , Ricardo Luis Louro Berbara  1
Affiliations

Structure-Property-Function Relationship in Humic Substances to Explain the Biological Activity in Plants

Andrés Calderín García et al. Sci Rep. .

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.

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Figures

Figure 1
Figure 1. PCA for the data obtained by loading the 13C-CP/MAS-NMR spectra of HSs from Histosols and composted materials.
(A,C) PCA performed using pure spectra. (B,D) PCA performed through integration of regions of pure spectra.
Figure 2
Figure 2. Multivariate curve resolution (MCR) performed by loading the 13C-CP/MAS-NMR spectra of HSs from Histosols and composted materials.
(A) MCR of HSs, (B) MCR of HAs and (C) MCR of Hus.
Figure 3
Figure 3. PCA of the data obtained by loading the FTIR spectra of HSs from Histosols and composted materials.
(A) soluble fractions, HAs and HS. (B) three fractions, HAs, HS and Hu.
Figure 4
Figure 4. PCA of the data derived from the elemental composition of HSs from Histosols and composted materials.
(A) soluble fractions, HAs and HS. (B) three fractions, HAs, HS and Hu.
Figure 5
Figure 5
PCA showing the relationship between the data resulting from the quantification of carbon types based on the 13C-CP/MAS-NMR spectra (A) and the elemental analysis (B) of humic fractions (HSs and HAs), and the root parameters evaluated in rice plants.
Figure 6
Figure 6. Principal component regression (PCR) of data from the 13C-CP/MAS-NMR and FTIR spectra and the root parameters of plant bioactivity.
(A, B) Humic acids (HAs) and (C,D) Humic substances (HS).
See this image and copyright information in PMC

References

    1. Senesi N. & Loffredo E. In Biopolymers. Lignin, humic substances and coal, Vol. 4 (eds Hofrichter M., Steinbuchel A.) 247–99 (Wiley-VCH, 2001).
    1. Pinton R., Cesco S. & Varanini Z. In Biophysico-Chemical processes involving natural nonliving organic matter in environmental systems, Vol. 2 (eds Senesi N. et al..) Ch. 9, 341–367 (John Wiley & Sons, 2009).
    1. Tachibana N. et al.. In Functions of natural organic matter in changing environment, Vol. 2 (Eds Xu J. et al..) 621–627 (Springer Verlag Science, 2013).
    1. Tan K. H. In Humic matter in soil and the environment: principles and controversies 2nd edn, (Ed Tan K. H. et al..) Ch. 10, 333–369 (Taylor & Francis, 2014).
    1. Nardi S., Pizzeghello D., Muscolo A. & Vianello A. Physiological effects of humic substances on higher plants Soil Biol. Biochem. 34, 1527–1536; doi: 10.1016/S0038-0717(02)00174-8 (2002). - DOI

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