Antioxidant response of bean seeds with contrasting vigor to cold stress

ABSTRACT Seed germination is a critical part of plant emergence and establishment in the field, and cold stress can affect the emergence potential and seedling formation. The present study aimed to determine the differences in the plant antioxidant system among common bean seeds with contrasting vigor and assess the relationship between seed lot vigor and antioxidant system. Six seed lots of common bean genotypes (BAF42, BAF44 and BAF55) with contrasting vigor levels (high and low vigor) were submitted to germination and cold tests. Lipid peroxidation, hydrogen peroxide, catalase, guaiacol peroxidase and ascorbate peroxidase were evaluated after cold stress. The high-vigor seeds were better able to overcome the cold stress, with the catalase enzyme activity more associated with vigor. Low-vigor seeds are more susceptible to stress, with high physiological damage in seedlings, due to the greater hydrogen peroxide accumulation in the embryonic axis. In order to maintain metabolic homeostasis, the low-vigor seeds increase the production of antioxidant enzymes in the seedlings, thus exhibiting a greater antioxidant enzymatic activity and hydrogen peroxide accumulation in response to cold stress.