Does Exogenously Applied Gallic Acid Regulate the Enzymatic and Non-Enzymatic Antioxidants in Wheat Roots Exposed to Cadmium Stress?

Authors : Ceyda OZFİDAN KONAKCİ

Pages : 279-285

Doi:10.18466/cbayarfbe.554860

View : 18 | Download : 13

Publication Date : 2019-09-30

Article Type : Research Paper

Abstract :The aim of the current study was to determine whether gallic acid (GLA) triggers the growth, osmoregulation and antioxidant system related to defense mechanisms in wheat roots to cadmium (Cd)-induced oxidative stress. For this purpose, wheat plants were hydroponically grown for 21 (d) and were treated with GLA (GLA1-2; 25 and 75 m M), Cd stress (Cd1-2; 100 and 200 m M) and their combination for 7 d. The significant reduction in growth (RGR) and osmotic potential ( Y P ) was observed under stress. After GLA applications in response to stress, RGR, Y P and proline (Pro) increased, except for 200 m M Cd plus 75 m M GLA. Under stress, hydrogen peroxide (H 2 O 2 ) was induced by the activated superoxide dismutase (SOD) activity but, NADPH oxidase (NOX) had no contribution on the accumulation of H 2 O 2 . Despite of the increased catalase (CAT) and glutathione reductase (GR), H 2 O 2 did not eliminate and then lipid peroxidation (TBARS content) was induced with the decreased scavenging capacity of hydroxyl radical (OH · ) under stress. Besides, to remove of H 2 O 2 content produced by SOD, H 2 O 2 could effectively scavenge through CAT activity in combination form of GLA and Cd. On the other hand, GLA did not induce the enzymes and non-enzymes related to Asada-Halliwell cycle (ascorbate peroxidase (APX), GR, dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), reduced and oxidized contents of glutathione (GSH and GSSG contents). Under high Cd concentration, GLA2 could not eliminate H 2 O 2 content because of increased NOX activity and then in this group (Cd2+GLA2) the scavenging capacity of OH · did not change and TBARS content increased. 
Keywords : Antioxidant enzymes, Asada Halliwell pathway, Cadmium, Gallic acid, Lipid peroxidation