Growth, photosynthetic pigments, and photochemical efficiency of sour passion fruit as a function of the cationic nature of water

The objective of this study was to evaluate the growth, photosynthetic pigments, and photochemical efficiency of sour passion fruit cv. BRS Rubi do Cerrado irrigated with waters of different cationic natures. The experiment was carried out from March 2019 to January 2020 in a protected environment belonging to the Academic Unit of Agricultural Engineering of the Federal University of Campina Grande (UFCG), Campina Grande, PB, Brazil. The treatments consisted of eight combinations of irrigation water with different cationic natures: S-1- Control; S-2-Na+; S-3-Ca2+; S-4- Mg2+: S-5-Na+ Ca2+; S-8-Na+ + Mg2+; S-7 Ca2+ + Mg2+; S-7 - Ca2+ + Mg2+. and S-8 - Na+ + Ca2+ + Mg2+. Plants in the control treatment (S-1) were irrigated using water with an electrical conductivity (ECw) of 0.4 dS m(-1), while the other treatments (S-2; S-3; S-4; S-5; S-6; S-7; and S-8) were subjected to an ECw of 3.5 dS m(-1). Sour passion fruit growth was affected by variations in the level of electrical conductivity, regardless of the cationic nature of irrigation water. The use of salinized water with sodium favored the synthesis of chlorophyll a, chlorophyll b, and carotenoids of passion fruit plants at 180 days after transplanting. The distinct cationic natures of irrigation water did not influence the fluorescence variables of sour passion fruit.