AMELIORATION WITH TITANIUM DIOXIDE NANOPARTICLE FOR REGULATION OF OXIDATIVE STRESS IN MAIZE (Zea mays L.).

In the present experiment, Zea mays L. was evaluated for its C₄ modality through oxidative stress responses. Moreover, under variable concentrations (0, 50, 100µM) of hydrogen peroxide, the impacts were variable and modulated with titanium dioxide nanoparticle (TiO₂-NP). Plants scored with elevated concentrations of H₂O₂ and superoxide (O₂.-) maximum by 1.31 & 1.52-fold respectively over 0µM H₂O₂. TiO₂-NP recovered those maximums with 8.69 & 7.89% as compared to control plants. The effects of H₂O₂ were moderated with malondialdehyde and carbonyl content by peak values 7.45 & 5.91% under TiO₂-NP treatment respectively. A depletion in proline content recorded under H₂O₂ stress but recovered through highest 1.23-fold with TiO₂-NP application. TiO₂-NP recorded NADP-ME activities up-regulated in concentration gradient of H₂O₂. Oxidative exposure was also documented by in-vivo detection of H₂O₂ and O₂.- by 3,3'-diaminobenzidine and nitroblue tetrazolium staining. For the anti-oxidative cascades superoxide dismutase activity had induced by 1.42-fold under H₂O₂ when pre-treated with TiO₂-NP. However, glutathione reductase activity was differentially modulated under H₂O₂ through interaction with TiO₂-NP. Activity of guaiacol peroxidase was significantly up-regulated by 1.07-fold when TiO₂-NP applied. The inductions of oxidative stress recorded more evident when a distinct polymorphism for GPX protein resolved variations in band intensities, but not in number. Activity of catalase experience a down-regulated trend all through the H₂O₂ exposure and had significant sensitivity to TiO₂-NP. The results depict the nature and reactivity of C₄ modules under oxidative stress that would be the selection pressures and that might be modulated with TiO₂-NP application. [ABSTRACT FROM AUTHOR]