CEREAL RESEARCH COMMUNICATIONS, cilt.50, sa.4, ss.811-820, 2022 (SCI-Expanded)
The present study investigated the effect of seed pretreatment with sodium nitroprusside (SNP) as nitric oxide (NO) donor on glyoxalase and antioxidant systems in germinating maize (Zea mays L.) seeds under methylglyoxal (MG) toxicity. The seeds were soaked in SNP solutions (0.0, 0.5, and 0.75 mM) for 8 h at 25 degrees C and then germinated in 0.0 (control) and 3 mM MG medium for 5 days under dark conditions (25 +/- 1 degrees C and 75% humidity). The MG alone caused a strong inhibition on seed germination and seedling growth (root and shoot length) while the SNP pretreatments improved the same parameters in the MG-stressed seedlings. The MG alone increased endogenous MG accumulation, and glyoxalase I (Gly-I) and Gly-II activities eliminating MG toxicity in both organs. In contrast, the SNP pretreatments reduced MG content and further stimulated both enzyme activities in MG-stressed seedlings. MG alone increased reactive oxygen species (ROS) such as O-2(.-) and H2O2, and lipid peroxidation (as malondialdehyde, MDA) levels. But the SNP pretreatments decreased ROS level, except for MDA content in seedlings exposed to MG. Moreover, MG alone stimulated superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities while it inhibited guaiacol peroxidase (GPX) activity. SNP pretreatments in seedlings stressed by MG further elevated SOD, GPX, and GR activities while it inhibited CAT and APX activities. The results showed that seed pretreatment with NO (particularly as 0.75 mM SNP) in maize seedlings exposed to MG ameliorated seed germination, seedling growth, MG accumulation, and oxidative stress by restoring the glyoxalase and antioxidant enzyme activities.