Enhancing salt stress tolerance in tomato plants (Solanum lycopersicum L.) through biostimulants

Biostimulants are substances or microorganisms applied in small quantities, improve plant growth and productivity by modulating their natural biological processes, distinct from fertilisers and pesticides. Derived from natural sources such as plant extracts, algae or beneficial microorganisms, they enhance nutrient uptake and tolerance to abiotic stress. In tomato (Solanum lycopersicum L.) exposed to salt stress, the application of biostimulants, including a combination of 70 % biofertilizer and 30 % biocompost (Bf70/Bc30), improved vegetative growth, photosynthesis and membrane stability while reducing malondialdehyde and excessive proline accumulation. These treatments also regulate the expression of genes related to proline biosynthesis and antioxidant activity, enhancing tolerance to salt stress. Thus, biostimulants constitute a sustainable approach to improve yield, quality and resilience of tomatoes, while reducing dependence on chemical inputs.