Reduced Glutathione in Modulation of Salt Stress on Sour Passion Fruit Production and Quality

Abstract

This study evaluated the effects of reduced glutathione (GSH) application on the production and quality of sour passion fruit irrigated with brackish water in the semi-arid region of Paraíba, Brazil. The experiment was conducted in drainage lysimeters under greenhouse conditions at the Center of Technology and Natural Resources of the Federal University of Campina Grande (UFCG). Treatments combined five levels of electrical conductivity of brackish irrigation water (Bw: 0.4, 1.2, 2.0, 2.8, and 3.6 dS m^-1) and four GSH concentrations (0, 40, 80, and 120 mg L^-1), arranged in a randomized block design with three replicates. Salinity levels above 0.4 dS m^-1 negatively affected fruit production and post-harvest quality of 'BRS GA1' sour passion fruit. Foliar application of 120 mg L^-1 GSH increased fruit yield, while 74 mg L^-1 GSH mitigated salt stress effects on production and pulp chemical quality. The 'BRS GA1' cultivar was highly sensitive to salinity, showing a 26.9% yield reduction per unit increase in Bw electrical conductivity above 0.4 dS m^-1. The results suggest that GSH can alleviate salt stress damage, improving crop productivity and fruit quality under semi-arid conditions.

Keywords: Passiflora edulis Sims; oxidative stress; salinity.

Figure 1

Total number of fruits—TNFs (A) and average fruit weight—AFW (B) of sour passion fruit as a function of electrical conductivity of brackish irrigation water Bw, observed during the harvest period from 99 to 150 days after transplanting.

Figure 2

Total number of fruits—TNFs of sour passion fruit as a function of concentrations of reduced glutathione, observed during the harvest period from 99 to 150 days after transplanting.

Figure 3

Production per plant—PROD (A), pulp volume—PV (B), and pulp yield—PY (C) of sour passion fruit as a function of the interaction between the electrical conductivity of brackish irrigation water Bw and the concentrations of reduced glutathione observed during the harvest period from 99 to 150 days after transplanting.

Figure 4

Hydrogen potential—pH (A), soluble solids—SSs (B), titratable acidity—TA (C), and soluble solids/titratable acidity ratio—SSs/TA (D) in the pulp of sour passion fruit as a function of the interaction between electrical conductivity of brackish irrigation water Bw and concentrations of reduced glutathione.

Figure 5

Ascorbic acid—AA (A), reducing sugars—RSs (B), non-reducing sugars—NRSs (C), and total sugars—TSs (D) in the pulp of passion fruit as a function of the interaction between the electrical conductivity of brackish irrigation water Bw and the concentrations of reduced glutathione.

Figure 6

Water consumption of sour passion fruit as a function of brackish irrigation water Bw salinity up to 155 days after transplanting.

Figure 7

Relative production of sour passion fruit as a function of the electrical conductivity of brackish irrigation water Bw, described by the plateau followed by linear decrease model [22].