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This study aimed to evaluate the physiological indices, growth, and seedling quality of the sour passion fruit cv. BRS SC1 as a function of irrigation with water of different cationic natures and exogenous application of salicylic acid. The experiment was conducted under plant nursery conditions at the CCTA/UFCG, Campus Pombal-PB, using a randomized block design set up in a 6 × 4 factorial arrangement referring to six cationic compositions of irrigation water (S1 – control, S2 - Na+, S3 - Ca2+, S4 - Na+ + Ca2+, S5 - Mg2+, and S6 - Na+ + Ca2+ + Mg2+) and four concentrations of salicylic acid - SA (0, 1.0, 2.0, and 3.0 mM), with three replications and two plants per plot. In the control treatment (S1), the plants were irrigated with the electrical conductivity level of 0.3 dS m-1, whereas the other treatments (S2, S3, S4, S5, and S6) used water with 4.0 dS m-1 obtained based on different cations, all in the form of chloride. The exogenous application of salicylic acid increased the content of chlorophyll b in the sour passion fruit seedlings. Salt stress negatively affected seedling growth. Seedling quality was affected by the electrical conductivity of irrigation water regardless of the cationic nature. Although showing reductions, the seedlings produced under high salinity showed a satisfactory Dickson quality index. The genotype cv. BRS SC1 is considered tolerant to salinity when irrigated with water salinized by Na+, Ca2+, Na+ + Ca2+, and Na+ + Ca2+ + Mg2+, and moderately tolerant when irrigated with water salinized by Mg2+., Objetivou-se avaliar os índices fisiológicos, o crescimento, e a qualidade de mudas de maracujazeiro-azedo ‘BRS SC1’ em função da irrigação com águas de diferentes naturezas catiônicas e aplicação exógena de ácido salicílico. O experimento foi conduzido sob condições de casa de vegetação, pertencente ao CCTA/UFCG, Campus de Pombal-PB, utilizando-se o delineamento de blocos casualizados com arranjo fatorial 6 × 4, sendo seis composições catiônicas da água de irrigação (S1 - Testemunha; S2 - Na+; S3 - Ca2+; S4 - Na+ + Ca2+; S5 - Mg2+ e S6 - Na+ + Ca2+ + Mg2+), e quatro concentrações de ácido salicílico - AS (0; 1,0; 2,0 e 3,0 mM) com três repetições e duas plantas por parcela. Na testemunha (S1), as plantas foram irrigadas com água de condutividade elétrica de 0,3 dS m-1 enquanto se utilizou, nos demais tratamentos (S2; S3; S4; S5 e S6) água com 4,0 dS m-1, obtida a partir de diferentes cátions, todos em forma de cloreto. A aplicação exógena de ácido salicílico aumentou o teor de clorofila b nas mudas de maracujazeiro-azedo. O estresse salino afetou negativamente o crescimento das plantas de maracujazeiro. A qualidade das mudas foi afetada pela condutividade elétrica da água, independente da natureza catiônica. Apesar de causar redução, as mudas produzidas sob elevado nível salino apresentou índice satisfatórios. O genótipo ’BRS SC1’ é considerado tolerante à salinidade quando irrigado com água salinizada por Na+; Ca2+; Na+ + Ca2+; Na+ + Ca2+ + Mg2+, e moderadamente tolerante quando irrigado com água salinizada por Mg2+.

Fertilization management is a technique that has been studied for the mitigation of salt stress in plants. In this perspective, this work aimed to evaluate the effects of combinations of potassium and nitrogen fertilization on the photosynthetic pigments, photosynthetic efficiency, and production of the West Indian cherry irrigated with waters of different salinities, between 420 and 550 days after transplanting. The experiment was conducted in an open field at the Center of Sciences and Agrifood Technology of the Federal University of Campina Grande, using 60 L lysimeters, in a randomized block design with a 5 x 4 factorial scheme, corresponding to five salinity levels of the irrigation water – ECw (0.3; 1.3; 2.3; 3.3, and 4.3 dS m-1) and four combinations of nitrogen and potassium fertilization (C1 = 70% N + 50% K2O; C2 = 100% N + 75% K2O; C3 = 130% N + 100% K2O, and C4 = 160% N + 125% K2O) of the dose recommended for the West Indian cherry, with three replications and one plant per plot. The cv. Flor Branca was studied through its grafting on a rootstock of the cv. Junco. The irrigation with ECw above 0.3 dS m-1 reduced the contents of chlorophyll a and b in the leaves, the photochemical efficiency, CO2 assimilation rate, instantaneous carboxylation efficiency, instantaneous water-use efficiency, and the number of fruits per plant. The combined fertilization with 70% of N + 50% of K2O increased the photosynthetic pigments, photosynthesis, and the number of fruits per plant, as well as mitigated the deleterious effects of water salinity on the production per plant up to the ECw of 2.3 dS m-1, which revealed to be the most adequate combination for West Indian cherry fertilization.