Enhancement of biomass production, salinity tolerance and nutraceutical content of spinach (Spinacia oleracea L.) with the cuticular wax constituent triacontanol

Abstract

The present study investigates the effect of foliar application of triacontanol (TRIA) on various physiological parameters with regard to crop yield and quality attributes of spinach (Spinacia oleracea L.) under normal growth conditions and salinity stress. Plantlets were grown for 21 days in perlite-containing pots supplemented with Hoagland’s nutrient solution, then they were subjected to 0 (control) or 150 mM NaCl. Two concentrations of TRIA (25 nM and 1 μM) were applied during seed germination and as foliar spray treatment, in itself or simultaneously with salt stress at 4-day intervals for three weeks. Exogenous application of TRIA enhanced germination energy and capacity, as well as shoot and root biomass of young spinach plants. Inhibition of net CO₂ assimilation (Pn) and of potential quantum yield of photosystem II (Fv/Fm), caused by salt stress, was significantly reduced by treatment with triacontanol. Increment of carotenoid pigment and ascorbate (vitamin C) content, as well as reduction of membrane lipid peroxidation due to triacontanol treatment improves the health-promoting quality of spinach leaves developed under high salinity conditions. The presented results offer a novel solution for optimization of spinach cultivation on soils affected by high salinity, as well as for an increased content of health-promoting metabolites of spinach leaves upon human consumption.