Antioxidants enzyme activity in Brassica oleracea var. acephala under cadmium stress

Abstract

When a plant is under heavy metals stress, it has different mechanism of coping with it. Brassica oleracea var. acephala (kale) is a plant that has an ability of heavy metal accumulation and removal of heavy metals from the ground. The plants were exposed to 50, 100, 200, and 500 μM of CdCl2 for 5days, in controlled in vitro conditions. Root length was measured to confirm the Cd effect on plant growth. There are five key antioxidants enzymes responsible for the regulation of heavy metals stress: superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), Peroxidase (POD) and Polyphenol oxidase (PPO). All enzymes showed significant activity, especially triggered by 500 μM CdCl2 in both varieties. The domestic sorts seem more resistant if compared to hybrid variety, showing significant lower expression of antioxidants enzymes at higher concentrations. In general, significant percentage of enzymes is more expressed in the hybrid Italian sort, Nero di Toscana, indicating the ability of domestic sorts to be more resistant to heavy metal stress.