Foliar application of H2O2 in hydroponic cultivation of cherry tomatoes under saline nutrient solutions

Abstract

The aim of this research was to evaluate the effect of foliar application of H₂O₂ in mitigating the effects of salt stress in Laranja cherry tomatoes grown in a hydroponic system. The study was conducted in the minicipality of Pombal, PB, in a greenhouse, in hydroponic cultivation using the laminar nutrient flow technique. The experimental design used was completely randomized, in a 4 × 5 split-plot scheme, where the plots corresponded to four levels of electrical conductivity of the nutrient solution - ECns (2.1, 2.8, 3.5, and 4.2 dS m^-1) and the subplots five concentrations of H₂O₂ (0, 12, 24, 36, and 48 µM), with six replicates and two plants per plot. The salinity of the nutrient solution starting from 2.1 dS m^-1, concentration with the concentration of 0 µM H₂O₂, inhibited the growth, partitioning of photoassimilates and the contents of photosynthetic pigments in cherry tomato plants, at 30 and 70 days after transplanting (DAT). The application of 36 µM H₂O₂ associated with the saline nutrient solution of 2.1 dS m^-1 resulted in a higher relative growth rate in number of leaves and stem diameter of cherry tomato plants in the period from 15 to 30 DAT. The ECsn above 2.1 dS m^-1 reduced the growth, photosynthetic pigments and total dry matter of Laranja cherry tomato plants, in hydroponic cultivation.