Biostimulant-induced mitigation of cold and drought stresses in zucchini plants

Currently, water and cold stresses are among the primary adverse factors affecting global crop production. Biostimulants are increasingly recognized as valuable tools for enhancing plant tolerance to abiotic stresses. F4.3S is a novel biostimulant that contains compounds such as allantoin, ascorbate, salicylic acid, amino acids such as glutamate, proline, and glycine, and sources of selenium, molybdenum, and cobalt. The objective of this study was to assess the tolerance of zucchini cv. Dynaic plants supplied with F4.3S to water and cold stresses and to identify the potential action mechanisms. For this purpose, an experiment was set up in pots with plants to which the biostimulant was applied before and after subjecting the plants to stress conditions, and parameters of biomass, stress, photosynthesis, and ethylene response were evaluated. The results showed that plants supplied with F4.3S presented a better tolerance to both stresses, which was reflected in higher biomass. The potential action mechanisms could be the stimulation of photosynthetic efficiency, preventing excessive stomatal closure, maintaining a high rate of net photosynthesis, and reducing reactive oxygen species generation. Additionally, increased accumulation of protective anti-stress compounds such as proline and carotenoids, along with reduced ethylene synthesis, likely contributed to the plants' enhanced recovery post-stress. In conclusion, the F4.3S biostimulant emerges as a promising agent for augmenting plant tolerance to abiotic stresses, which is crucial for sustainable agricultural practices.