Uso do peróxido de hidrogênio para mitigar os efeitos do estresse salino em coentro cultivado em sistema hidropônico

Abstract

The objective of this work was to evaluate the role of hydrogen peroxide as a mitigator of the deleterious effects of saline stress in coriander plants grown in a hydroponic system. The work was carried out in a greenhouse in a hydroponic system of the DWC type (Deep Water Culture) in a completely randomized design. The combination of H2O2 doses (0.1; 1; 10 and 100 mM of H2O2) and imbibition times (12, 24 and 36 h) resulted in 14 treatments, with four replications. The growth variables dry and fresh matter of shoots and number of leaves were analyzed. With the fresh matter data of the aerial part, the tolerance index (TI) was determined and four outstanding treatments were selected to determine the levels of pigments (chlorophylls and carotenoids) and inorganic solutes sodium (Na+), potassium (K+) and chloride (Cl-). Biomass and chlorophyll contents of coriander plants were reduced by saline stress. However, in general, the plants that were submitted to pretreatment with H2O2 were less affected by the stress condition. Seed conditioning at a concentration of 0.1 mM H2O2 + 36 h of imbibition increased the tolerance of coriander plants to salinity. H2O2 in increasing salt tolerance acts with signaling pathways and is directly associated with the maintenance of ionic homeostasis by reducing the Na+ and Cl- content in the leaves.