Hydrogen peroxide in regulation of plant metabolism: Signalling and its effect under abiotic stress

In plants, hydrogen peroxide (H₂O₂) acts as a signalling molecule that facilitates various biochemical and physiological processes. H₂O₂ is a versatile molecule, involved in several cellular processes both under stress and stress-free conditions. In regulating plant metabolism under stress conditions, exogenous application of H₂O₂ also plays a pivotal role which is manifested in improved growth, photosynthetic capacity, and antioxidant protection. Abiotic stress is an inevitable environmental factor that extensively affects and reduces growth, quality, yield, and productivity of plants. Several signalling pathways involved in H₂O₂-mediated stress and defense responses have been extensively studied and there is ample scope of additional research that could further clarify the mechanism and modulating factors which regulate these pathways. An attempt has been made to dissect the role of H₂O₂ under low temperature stress and how it affects plant growth and development, photosynthetic capacity, regulation of antioxidant system, and signalling.