Cationic Nature of Water and Hydrogen Peroxide on the Formation of Passion Fruit Seedlings1

Abstract

This study was carried out with the objective of evaluating the water relations, photosynthetic pigments and growth of passion fruit cv. BRS Rubi do Cerrado, as a function of the cationic nature of irrigation water and exogenous application of hydrogen peroxide. The experiment was carried out under greenhouse conditions in Pombal – PB, Brazil. The experimental design was randomized blocks, in a 6 × 4 factorial scheme, corresponding to six cationic nature of water - CNW (S1 - Control; S2 - Na+; S3 - Ca2+; S4 - Na++Ca2+; S5 - Mg2+ and S6 - Na++Ca2++Mg2+) and four concentrations of hydrogen peroxide - H2O2 (0, 20, 40 and 60 μM), distributed in a randomized block design with four replicates. Plants in the control treatment (S1) were irrigated using water with electrical conductivity (ECw) of 0.3 dS m-1, while those of the other treatments (S2; S3; S4; S5 and S6) were subjected to ECw of 3.0 dS m-1, prepared with different cation(s). Application of 60 μM of H2O2 reduced the percentage of intercellular electrolyte leakage in plants irrigated with water of calcic composition. Salinity of water composed of sodium, sodium+calcium and sodium+calcium+magnesium, and H2O2 concentrations of 40 and 60 μM resulted in lower leaf water potential. The biomass accumulation of passion fruit was more sensitive to the variation of the electrical conductivity of the water. Regardless of the cationic nature, the use of water with electrical conductivity of 3.0 dS m-1 produced passion fruit seedlings with a Dickson quality index higher than 0.2, considered acceptable.

Indução de tolerância com ácido salicílico em maracujazeiro-azedo irrigado com águas de diferentes composições catiônicas

“…Despite being considered a fruit species of significant importance to Northeastern Brazil, this region shows limitations for the expansion of irrigated agriculture due to low rainfall rates and high evapotranspiration, resulting in a water scarcity scenario that forces producers to use underground water sources with high salt contents (Veloso et al, 2018). Furthermore, the chemical nature of these water bodies is diversified and influenced by factors such as regional climatic conditions, the mineralogical composition of rocks, water residence time, and the underground water flow (Lima et al, 2016;Silva et al, 2018a;Lima et al, 2021a).…”