Plant priming with sodium cholate increases oxidative stress response in maize

The elicitor activity of sodium cholate (NaC) was examined in maize (Zea mays, L.) leaves and roots. The effect of this bile salt on the oxidative status in maize metabolism was determined by spectrophotometric methods, measuring the production of superoxide anions (O2•- radicals), activity of three antioxidant enzymes (superoxide dismutase – SOD, EC 1.15.1.1; catalase – CAT, EC 1.11.1.6 and pyrogallol peroxidase – PPX, EC 1.11.1.7), content of malondialdehyde (MDA), an end product of lipid peroxidation, the contents of total phenols, tannins and flavonoids, as well as measuring scavenging capacity of plant extracts by the DPPH and ABTS assays. In addition, concentration of NaC remaining in the growth media was measured. The results showed that all tested NaC concentrations caused mild oxidative stress due to increased O2•- radical production, activity of enzymes, and contents of all measured phenolic compounds after seven days of treatment. The highest percentage of NaC remaining in the maize growth medium after seven days was measured at the lowest initial concentration, 20 mg L−1, indicating that this concentration was the least absorbed by the maize. Results from this study provide important insights for sustainable agriculture.