Evaluation of hydrogel use in the development of Rapanea ferruginea with water restriction by vibrational Fourier Transform Infrared Spectroscopy (FTIR-UATR)

This study evaluated the use of hydrogel on the development of Rapanea ferruginea under water restriction through Vibrational Fourier Transform Infrared Spectroscopy (FTIR-UATR). Seedlings of approximately 30 cm height were transferred in pots with 3 L of soil. The group of seedlings was separated into 5 different triplicate treatments according to the amount of hydrogel, as follows: H1 (25%), H2 (20%), H3 (15%), H4 (10%) and S (control without hydrogel). The applied hydrogel was mixed homogeneously with the soil. All treatments were irrigated with 40 mL of water. FTIR spectra were obtained from fresh leaves collected during 13 months of monitoring. The correlation of the hydroxyl (water) band with the main biomolecules between treatments with the control was evaluated using the Mann-Whitney test (p<0.05). The biomolecule bands were subjected to principal component analysis (PCA) and hierarchical clustering analysis (HCA). The results indicate a significant correlation of the water band with the lipid, hemicellulose, cell wall and starch components in the species. The use of hydrogel resulted in a significant difference in the water absorption band in relation to the control group through the Mann-Whitney test and in biomolecules as the HCA and PCA analysis suggested. The best development was observed in groups H4 (10%), H2 (20%) and H3 (15%). The use of hydrogel positively influences the biomolecular development of the Rapanea ferruginea and monitoring is viable by FTIR. Keywords: FTIR infrared spectroscopy, plant water management, superabsorbent polymer.