Óxido nítrico como mitigador morfofisiológico em Rabanete sob déficit hídrico (raphanus sativus l.) Bananeiras - pb 2025

Abstract

Climate change and the intensification of drought affect agricultural productivity, generating socioeconomic impacts and threatening biodiversity and food security. In this context, studies have investigated the effects of water stress on plant development and the defense mechanisms activated, such as biomass reallocation to the roots. Radish (Brassicaceae) is a vegetable that exhibits adaptations to adverse conditions, but its productivity is compromised when water availability falls below 80% of the soil’s water-holding capacity (WHC). In this scenario, bioregulators such as nitric oxide (NO) have emerged as alternatives to mitigate the effects of drought. This study evaluated the effectiveness of the NO donor sodium nitroprusside (SNP) on the morphophysiology of radish under water stress. Over a period of 28 days, plants were subjected to three irrigation regimes: daily irrigation (80% WHC), irrigation suspension from 14 to 21 days after sowing (DAS), and from 21 to 28 DAS. Plants were sprayed weekly with 15 mL of SNP (100 μM) or water (0 μM, control). The experiment followed a completely randomized design (CRD) in a 3 × 2 factorial arrangement (irrigation regimes × solution application), with tem replications. Gas exchange, chlorophyll a fluorescence, photosynthetic pigments, electrolyte leakage, relative water content, and biomass partitioning were evaluated. The results demonstrated the importance of water for radish growth and the potential of SNP to mitigate the effects of water stress in plants stressed between 14 and 21 days after sowing (DAS), despite the risk of, in some cases, inducing oxidative stress.