Salinity tolerance in Cucumis sativus seedlings: the role of pistachio wood vinegar on the improvement of biochemical parameters and seedlings vigor.

Background: Soil salinity is a major environmental concern that affects the production of salt-sensitive crops such as cucumbers by limiting their growth and development. Wood vinegar is used as a biostimulant in agriculture to enhance crop productivity and improve the plant's defense system against pathogens, while studies show that it can also protect against oxidative stresses. A factorial experiment was arranged based on a randomized completely design with three replicates and carried out to mitigate the negative effects of sodium chloride (NaCl) on cucumber seedlings through pistachio wood vinegar (PWV) foliar spraying. The seedling was sprayed at the three-leaf stage of growth by PWV (0, 1500, and 3000 ppm) and salinity stress (0, and 150 mM NaCl) was imposed at the five-leaf stage gradually (from 25 to 150 mM NaCl) in the modified Hoagland's solution.

Results: The intense salinity stress reduced the fresh and dry mass of root and shoot by 25, 5, 34, and 13%, and decreased chlorophyll a, b, total, and carotenoids by 14, 45, 28, and 44%, respectively compared to the control. Also, in the treated plants with PWV decreased levels of total protein (14%). While PWV treatment decreased the negative effects of the intense salinity stress and enhanced the fresh mass root (41%), dry mass shoot (33%), shoot length (23%), leaf area (34%), leaf number (63%), Chl a (14%), Chl b (11%) and carotenoids (56%). Under the intense salinity stress, the foliar spraying of PWV, 3000 ppm, decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) by 7 and 10%, respectively compared to the control.

Conclusions: This study shows that the use of PWV (1500 ppm) via its nutrient and bioactive components is effective in improving the negative effects of the salinity (150 mM NaCl) in cucumber seedlings.