Exogenous Selenium Pretreatment Protects Rapeseed Seedlings from Cadmium-Induced Oxidative Stress by Upregulating Antioxidant Defense and Methylglyoxal Detoxification Systems

摘要: The protective effect of selenium (Se) on antioxidant defense and methylglyoxal (MG) detoxification systems was investigated in leaves rapeseed (Brassica napus cv. BINA sharisha 3) seedlings under cadmium (Cd)-induced oxidative stress. Two sets 11-day-old were pretreated with both 50 100 μM Se (Na2SeO4, sodium selenate) for 24 h. concentrations CdCl2 (0.5 1.0 mM) imposed separately or the Se-pretreated seedlings, which grown another 48 Cadmium stress at any levels resulted substantial increase malondialdehyde H2O2 levels. ascorbate (AsA) content decreased significantly upon exposure to Cd amount reduced glutathione (GSH) increased only 0.5 mM CdCl2, while disulfide (GSSG) level Cd, concomitant decrease GSH/GSSG ratio. activities peroxidase (APX) S-transferase (GST) concentration (both CdCl2), reductase (GR) (GPX) moderate CdCl2) then severe (1.0 CdCl2). Monodehydroascorbate (MDHAR), dehydroascorbate (DHAR), catalase (CAT), glyoxalase I (Gly I), II II) Cd. Selenium pretreatment had little nonenzymatic enzymatic components normal conditions; i.e., they slightly GSH APX, GR, GST, GPX. On other hand, Cd-induced showed a synergistic effect; it AsA contents, ratio, MDHAR, DHAR, GPX, CAT, Gly I, ultimately MDA However, most cases, better results compared Se. indicate that exogenous application low increases tolerance plants damage by enhancing their MG systems.