Differential effect of UV-B radiation on growth, oxidative stress and ascorbate-glutathione cycle in two cyanobacteria under copper toxicity

► UV-BL and UV-BH exerted differential effect on both organisms under Cu toxicity. ► UV-BH exacerbated Cu toxicity in P. foveolarum and N. muscorum. ► However, UV-BL protected both organisms against Cu toxicity. ► AsA-GSH cycle played crucial role in protection against oxidative stress. ► P. foveolarum is more tolerant to Cu and UV-BH than N. muscorum.