Salicylic Acid Signals Plant Defence Against Cadmium Toxicity

Plant growth is adversely impacted by heavy metals, posing a threat to the health of humans and animals within the food chain. Scientific evidence substantiates that both essential and non-essential heavy metals lead to significant reductions in both growth and biomass accumulation. Heavy metals exert their influence on flora at various levels, ranging from the molecular to the entire plant, resulting in detrimental effects. The role of salicylic acid (SA) in plant defense against both biotic and abiotic stresses has been extensively investigated as an enigmatic signaling molecule. Recent research has specifically delved into the modulation of cadmium tolerance in plants through SA signaling. SA exposure has been studied using presoaking, hydroponic exposure, and spraying methods. In contrast, excessive levels of exogenous SA aggravated Cd’s toxic effects, whereas pre-treatment with appropriate amounts of SA mitigated Cd damage. In addition to restructuring cell walls, regulating the uptake of cadmium and other ions, enhancing antioxidant defenses, and controlling processes such as photosynthesis, glutathione synthesis, and senescence, salicylic acid functions as a secondary messenger as well. As a result of these discoveries, salicylic acid is becoming increasingly important to phytotoxicology. Its multifaceted functions play a critical role in orchestrating a diverse array of physiological and genetic adaptations in plants.