UV-B radiation induces biphasic burst of hydrogen peroxide in mesophyll Chlorella vulgaris

The fluctuations of hydrogen peroxide and total hydroperoxides were followed up at different time points in UV-B-irradiated cell suspension cultures of the green microalga Chlorella vulgaris . A biphasic burst of hydrogen peroxide was recorded, while cell viability was strongly reduced. This pattern is similar to the two wave oxidative burst in plants expressing hypersensitive response to pathogens and PCD and implies the occurrence of a PCD-like response in UV-B-exposed unicellular green algae.