Oxidative Stress Biomarkers in Blackberry Roots

The malondialdehyde (MDA) content in blackberry roots was determined by the thiobarbituric acid (TBA) method [67 (link)]. The superoxide anion radical (O₂^·−) generation rate was determined according to the hydroxylamine oxidation reaction method [68 ]. The hydrogen peroxide (H₂O₂) content was determined using a kit (A064-1-1, Nanjing Jiancheng Bioengineering Institute, Nanjing, China). The SOD activity was determined by the nitro blue tetrazolium (NBT) method [69 (link)]. POD activity was determined by catalytic hydrogen peroxide reactions [23 (link)]. The amount of enzyme that catalyzed 1 microgram of substrate per minute per gram of tissue was defined as a unit of POD activity (U) at 37 °C. The CAT activity was determined by the ammonium molybdate method [70 (link)]. One unit of CAT activity (U) was defined as the amount of 1 μM H₂O₂ decomposed per second per gram of tissue. The ascorbic acid (AsA) content was determined according to the method of Asami et al. [71 (link)], and the reduced glutathione (GSH) content was determined according to the method of Anderson [72 (link)]. The SP content was determined using Coomassie brilliant blue staining [73 (link)].