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

Abstract

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.

Modalities of NADP-malic enzyme activities under light and darkness indicate its regulation with reference to C4 weed

“…Thereafter, its balance in the ratio of reduced to oxidative state causes over reduced oxygen and its transformation into active/reactive oxygen species (ROS) (34). So, a plant species tolerant to oxidative degeneration would be maintaining a stable proportion of reduced to oxidised redox through some key enzymatic pathways (35). From other C4 species, NADP-ME also reported to be most important in complementation of CO2 enrichment under stress condition (3).…”

Regulation of NADP-Malic Enzyme Activity in Maize (Zea mays L.) under Salinity with Reference to Light and Darkness

“…The uniform size of the leaf disc from the illuminated or dark-adapted set was thoroughly crushed in liquid nitrogen into a fine powder. The powder was mixed with extraction buffer containing 100 mM Tris-HCl (pH 7.3), 1.0 mm EDTA, 1.0 mM PMSF, 2% glycerol, 100 µM β-ME, 25 mM MgCl 2 , 20 mM K 2 HPO 4 , and 0.1 mM protease inhibitor cocktail as the modified form [11]. The mixture was centrifuged at 12,000× g for 15 min at 4 • C and the supernatant was subjected to 80% ammonium sulphate cut, overnight at 4 • C. The pellet was recovered and separated by a cellophane tube (50K MWCO) in the same buffer mixed with 0.05% SDS, 25 µM BSA, 0.5 mM MgCl 2 , and 1 mM DTT.…”