Salicylic acid increases tolerance to oxidative stress induced by hydrogen peroxide accumulation in leaves of cadmium-exposed flax ( Linum usitatissimum L.)

[摘要] The aim of this study is to investigate the impacts of exogenous salicylic acid (SA) pretreatments on hydrogen peroxide (H 2 O 2 ) accumulation, protein oxidation, and H 2 O 2 -scavenging enzymes in leaves of Cd-treated flax seedlings. Cd-enhanced H 2 O 2 levels were related to increased activities of guaiacol peroxidase (POX, EC 1.11.1.7) and ascorbate peroxidase (APX, EC 1.11.1.11), and were independent of changes in catalase (CAT, EC 1.11.1.6) and superoxide dismutase (SOD, EC 1.15.1.1) activities. In control flax seedlings, exogenous SA pretreatments inhibited the activity of CAT, resulted in an enhanced production of H 2 O 2 suggesting that SA requires H 2 O 2 to initiate an oxidative stress. However, although leaves of Cd-free flax seedlings pretreated with SA accumulated in vivo H 2 O 2 by 1.2-fold compared with leaves of Cd-only exposed ones; the damage to growth and proteins after the exposure to Cd was significantly less, indicating that SA can regulate the Cd-induced oxidative stress. Moreover, the Cd-treated seedlings primed with SA exhibited a higher level of total antioxidant capacities and increased activities of H 2 O 2 -detoxifying enzymes.

[学科分类] 纳米科学和纳米技术

[关键词] cadmium;salicylic acid;hydrogen peroxide;antioxidant enzymes