The effect of H2O2 on elongation growth and oxidative stress in maize coleoptile cells treated with auxin and fusicoccin

The aim of this study was to evaluate the impact of hydrogen peroxide (H₂O₂) on the elongation growth of maize coleoptile cells induced by auxin (IAA) and fusicoccin (FC) according to the "acid growth theory". The key component of this process is PM H⁺-ATPase activity and the resulting proton extrusion. In order to complete this objective, measurements of coleoptile growth were made, pump activity was analyzed through changes in environmental pH and cell membrane potential, and the impact on oxidative stress in response to H₂O₂ was determined. It was found that although hydrogen peroxide restricts acid growth induced by both IAA and FC to a similar level, the PM H⁺-ATPase activity is inhibited differently. These findings indicate that in the presence of H₂O₂, the previously described wall-stiffening process might be the primary limiting factor in the elongation growth of maize coleoptile cells.