Influência da adição de NPK no crescimento, respostas bioquímicas e estresse oxidativo em Pavonia humifusa A. St.-Hil. (Malvaceae) sob estresse hídrico

Abstract

Water stress can trigger a series of plant metabolic changes, affecting their biochemistry and morphology. The variability of rainfall cycles creates challenges to adaptation. However, nitrogen supplementation (NPK) can play a crucial role in this context, as these nutrients are fundamental for maintaining metabolism, especially under stress conditions. The present study evaluated the effects of nutritional supplementation on the biochemical and morphological responses of Pavonia humifusa plants under water stress. After 21 days of supplementation, water stress was induced for 29 days. The experiment included two NPK treatments: with and without NPK associated with two conditions of water availability: control and stress. Biometric parameters (aerial and root dry biomass), physiological parameters (relative water content and SPAD index), primary metabolism parameters (pigment and proline content), stress markers (malondialdehyde and hydrogen peroxide) and enzyme activities (superoxide dismutase, catalase and ascorbate peroxidase) were analyzed. ANOVA analyzed the data at 5% and the means were compared by the SNK test using the R software. The analyses carried out indicate that after nutritional application with NPK, P. humifusa showed a better growth rate, as well as a higher total chlorophyll content in vivo. The plants supplemented with NPK also showed better adaptation to water stress with a reduction in oxidative stress. In addition, with NPK supplementation, P. humifusa responded to be less susceptible to water stress by increasing the enzymatic activity of SOD and Proline, the main osmoregulatory amino acid in water stress conditions. The results obtained suggest that nutritional supplementation with NPK plays an important role in biochemical and physiological regulation against water stress in P. humifusa.