Oxalic Acid: A Dual Role in Plant Stress Response and Detoxification

Oxalic acid (OA) is a dicarboxylic organic acid that serves a dual function in plants: acting as a protective agent against environmental and biotic stressors and, paradoxically, posing potential toxicity risks when accumulated excessively. This multifaceted molecule is involved in a wide range of physiological and biochemical responses, including chelation of heavy metals, reactive oxygen species regulation, interaction with plant hormones, and genetic modulation under stress conditions. However, despite the growing body of research, substantial gaps remain in our understanding of its regulation, biosynthesis, signaling functions, and environmental implications. This chapter explores both the protective and toxicological dimensions of OA, highlighting its potential in phytoremediation and sustainable agriculture, industry, and biotechnological applications while proposing future research directions to bridge current knowledge gaps.