Effect of Temperature and Duration of Root CHILLING on the Balance between Antioxidant Activity and Oxidative Stress in Spinach

抄録

It has been proposed that cold stress applied to the root area promotes the production of reactive oxygen species and the increase in antioxidants levels in the plant body. However, changes in the balance between antioxidant activity and oxidative stress in plants under different levels of cold stress remain unexplored. Here, we assessed ascorbic acid content, superoxide dismutase activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, as proxies of antioxidant activity, and malondialdehyde (MDA) content, as an oxidative stress marker, in spinach. The root area was exposed to cold stress for 2, 4, 5, 6, and 7 days at various temperatures (4℃, 7℃, 10℃, and 14℃). Root chilling at 4℃ and 7℃ induced increases in ascorbic acid and DPPH scavenging levels, which were accompanied by the increase in MDA content, as cold exposure progressed. In contrast, root chilling at 10℃ and 14℃ increased antioxidant capacity without the increase in MDA concentration. The results of this study indicate that moderate cold stress applied to the root area of spinach could increase its antioxidant functions without accumulation of oxidative stress-related substances.