UV-B Radiation and Its Differential Impact on Two Liverwort Species: An Eco-physiological Assessment

Abstract

The recent depletion of the stratospheric ozone layer—which normally filters out harmful ultraviolet-B (UV-B) radiation (280–315 nm)—has increased the need to understand how UV-B affects and is tolerated by photosynthetic organisms in different environments. In this study, two bryophyte species were exposed to elevated levels of UV-B radiation to assess its effects on growth and oxidative responses. The two species reacted differently, with Cythodium cavernarum showing greater sensitivity than Riccia discolor. A more pronounced decline in photosynthetic pigment content was observed in C. cavernarum. The effects on photosynthetic performance varied depending on both the UV-B dose and the species. Additionally, both enzymatic and non-enzymatic antioxidant systems were activated in a dose-dependent manner in both species; however, higher UV-B doses led to significant antioxidant loss and increased oxidative damage. Overall, the findings indicate that Cythodium cavernarum is more vulnerable to enhanced UV-B radiation compared to Riccia discolor.