INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Bentonite-based nanoclays for the vehiculization of phytohormones, aminoacids and polisacharides: promising biomaterials for agricultural applications
Autor/es:
COLMAN, S.; MERINO, D.; ALVAREZ, V. A.; MANSILLA A.Y.; CHEVALIER, M.T.; CASALONGUÉ, C.A.; IGLESIAS, M.J.; BRACONE, M.E.
Lugar:
Sorocaba, San Pablo
Reunión:
Workshop; III Workshop in Environmental Nanotechnolgy; 2018
Institución organizadora:
University of Sorocaba
Resumen:
Agriculture face a growing world demand for food in combination with a reduction of fertile area due to climate changesand accumulation of pesticides and fertilizers. In this context, the development of new bioactive materials with emergingproperties fits with the actual challenge of augmenting crop productivity with reduced environment impact. Bentonite(Bent) is one of the most commonly used clays because of its easyindustrial scaling, and low toxicity which allows its usein food and agriculture. Bent is considered nanoclay with high cation exchange capacity, large surface area and porosity.Consequently, it has the possibility of lodging multiple organic cations between its sheets. The aim of our project is theproduction and characterization of bent-based nanocomposites for the vehiculization and controled delivery of biologicalcompounds with potencial impacts on plant phisiology. Bent were selected as matrices to immobilize thephytohormonesalicilic acid (SA), a master regulator of plant defense programs against biotic and biotic stress; themultifunctional aminoacid proline as an antioxidant and osmoprotector against draught and salt stresses; and chitosan(CS) polysaccharides which improve defense responses to biotic and abiotic stresses. Bent was provided by Minarmco SA,Salicylic acid (AS) were provided by Sigma Aldrich, Chitosan (CS) was provided by Drogueria Sapporiti and Proline wasprovided by Biopack. Bent−CS, Bent-AS and Bent-Pro nanoclays were obtained by cationic exchange by preparing asolution of the active agent and stirred it with a Bent dispersion in distilled water for 2 h. The nanoclays obtained werethen centrifuged, washed 3 times with distilled water, and lyophilized. Analyses were performed using TA Auto-MTGAQ500 Hi-Res equipment in air atmosphere. X- Ray Difraction (XRD) patterns were obtained in a Analytical ExpertInstrument equipment (K∞Cu=1.54 Å) from 2θ = 3 º to 60 º. Fourier transform infrared spectroscopy (FTIR): Nicolet FTIR7600 spectrometer was used with an ATR accessory. Bioassays: Bent composites were sprayed at different times andconcentrations on tomato plantlets (Solanumlycopersicum of cv. Platense) for the analysis of biochemical andphysiological responses. The powder XRD patterns of the original and modified hybrid bentonites have shown that thedistance between the planes of the crystal lattice of the modified clays (with AS, CS and Pro) was found to be higher thanfor unmodified bentonite. The increased interlayer spacing of the clay after modification with each active principle (AP)indicate that at least some part of the AP was intercalated and is housed in the clay strata. DTGA curves showed a peakaround 300 °C in the thermogram corresponding to the modified clay that does not appear in those to the unmodifiedclay. This peak would indicate retarded degradation of intercalated active principle inside the clay. The absence of thepeak corresponding to the hydroxyls (OH), centered at 3500 cm-1 and the carbonyl group (C=O) centered at 1710 cm-1 inthe infrared spectra (FTIR) of the modified clay could be also related to the intercalation of the AP in the clay sheets. Bent-CS and Bent-SA clays sprayed on 10 days-old tomato seedlings elicit the accumulation of the PR2 pathogenesis-related(PR) protein which is currently used as markers for innate immunity[8]. Bent-SA application protects tomato plants againstthe infection with the bacterium Pseudomonas syringe pv. tomato DC3000. In the case of Bent-CS antimicrobial actionsagainst Pseudomonas syringe p.v.30 tomato DC3000 and the necrotrophic fungus Fusariumsolani f. sp. eumartii isdemonstrated. Currently, experiments are in progress in order to evaluate the role of Bent-SA and Bent-proline in theprotection of plants against abiotic stress. Our findings validate a promising scenario for the application of Bentcomposites in the modulation of plant defense programs to respond to changing environment and improved cropperformance.