Biostimulant modulate the physiological and biochemical activities, improving agronomic characteristics of bell pepper plants under salt stress

Salinity is one of the most important environmental stresses affecting plant growth and metabolism, in irrigated areas of arid and semi-arid regions; and the use of biostimulants seems to be an efficient alternative to improve the productivity of plants under saline conditions. This study investigated the effects of salinity stress by applying different electrical conductivities (0.5, 1.5, 2.5, 3.5, and 4.5 dS m ^− 1 ) of irrigation water in combination with foliar application of biostimulant (VIUSID Agro) (0, 0.3, and 0.6 mL L ^− 1 ) on the growth, productivity, physiological, and biochemical responses of bell pepper plants, in a greenhouse. Done in a factorial design and completely randomized layout with five replications and the parameters evaluated were: growth and production components; gas exchange, chlorophyll fluorescence, chlorophyll index, relative water content, electrolyte extravasation; organic components; and antioxidant enzymes activity (catalase and ascorbate peroxidase); and malondialdehyde content. The results showed that salinity caused a significant reduction in growth, decreased chlorophyll levels, increased malondialdehyde levels, osmorregulators and antioxidant enzyme activity. Both doses of the biostimulant effectively mitigated the effects of salt stress by maintaining higher chlorophyll levels (15% increase), improving photosynthetic performance (20% increase), and improving fruit size and quality, leaf water status, ultimately leading to improved crop performance. The foliar application of the biostimulant was an effective strategy to increase the tolerance of bell pepper plants under salt stress conditions and can be a sustainable solution for agricultural production under salinity conditions in irrigation water.