Spermidine trihydrochloride maintains cell membrane stability, increases antioxidant enzymes activities, improving photosystem II (PSII), and relevant gene expression. Spermidine trihydrochloride significantly decreases the H₂O₂ and O₂^.- contents^[1]. In Vitro: Spermidine plays a crucial role of against abiotic stresses, such as salt, drought, heat, and salinity-alkalinity stresses in tomato, cucumber, rice^[1].