HIGHLIGHTS:

Substrate salinity increased due to application of liquid fertilizers associated with 4.0 dS m^-1 water.

Water-use efficiency in ‘Guinezinho’ yellow passion fruit enhanced under 4.0 dS m^-1 water salinity.

Positive impact of Codasal™ application on CO₂ assimilation rate and carboxylation efficiency in yellow passion fruit seedlings.

ABSTRACT

The Northeast region of Brazil is the primary producer of yellow passion fruit. In recent years, water scarcity has led passion fruit growers to use highly saline water for cultivation. Therefore, implementing technologies that alleviate the negative effects of salt stress on plants is a promising approach, particularly in semi-arid conditions. This study aimed to assess the efficacy of organomineral fertilizers in mitigating salt stress effects on chlorophyll-a fluorescence and gas exchange in ‘Guinezinho’ yellow passion fruit seedlings. The treatments were arranged in randomized blocks with four replicates and four seedlings per plot, following a 2 × 3 factorial design. The factors considered were irrigation using water with low (0.18 dS m^-1) and high (4.0 dS m^-1) electrical conductivity and three liquid organomineral attenuators (Codasal™, Aminoagro Raiz™, and a mixture of Codasal™ + Aminoagro Raiz™ at a 1:1 v/v ratio), applied through fertigation. Irrigation with water containing 4.0 dS m^-1 electrical conductivity, combined with liquid fertilizers, resulted in increased substrate salinity, and reduced stomatal conductance in yellow passion fruit seedlings, particularly when Codasal™ was applied. Application of Codasal™ alone or in combination with Aminoagro Raiz™ significantly enhanced variable fluorescence, quantum efficiency of PSII, CO₂ assimilation rate, and instantaneous carboxylation efficiency in ‘Guinezinho’ yellow passion fruit seedlings.

Key words:
Passiflora edulis Sims; salt stress; mitigation; organomineral sources; gas exchange