Abstract

Because marine organisms have evolved to adapt to a wide variety of environmental factors on varying temporal and spatial scales, the antioxidative metabolic pathway are different. The aim of this study was to investigate the different antioxidative response of Ulva Prolifera ( U. prolifera ) that have been exposed to high temperature (UpHT) or low-temperature (UpLT) stresses. The results of our study suggested that mainly UpHT and not UpLT increased the expression of superoxide dismutase (SOD), catalase (CAT), and L-ascorbate peroxidase (APX) more than those in the medium-temperature (UpMT) controls. In addition, biological index analyses indicated that both SOD and CAT activities increased after culturing for 48   h. The chlorophyll levels increased to the highest point after culturing for 4 d in the UpHT group but remained unchanged in the UpLT group. In addition, peroxide (H 2 O 2 ) and malondialdehyde (MDA) levels increased under UpHT but remained unchanged under UpLT stimuli. We suggest that our findings have significantly improved our understanding of the different molecular mechanisms involved in the tolerance of algae to UpHT or UpLT stimulus, which might explain the seasonal blooms of U. prolifera .