UV-B radiation arising from stratospheric ozone depletion influences the pigmentation of the Antarctic moss Andreaea regularis
Changes to the radiative environment arising from stratospheric ozone (O3) depletion and subsequent associations between these changes and the pigmentation of the moss Andreaea regularis were measured in late austral spring and early summer 1998 at Rothera Point on the western Antarctic Peninsula (67 S, 68 W). A strong relationship between O3 column depth and the ratio of UV-B to PAR irradiance (FUV-B/FPAR) was recorded at ground level (r2 = 92%, P<0.001). Weaker, but significant, associations between O3 column depth and ground level unweighted and biologically effective UV-B radiation (UV-BBE) were also found. Regression analyses indicated that FUV-B/FPAR was the best predictor for concentrations of UV-B screening pigments and total carotenoids extracted from plant tissues. Concentrations of these pigments were loosely (r2 = c. 30%) but significantly (P<0.01) positively associated with FUV-B/FPAR. Concentrations of UV-B screening pigments were also positively associated with irradiances and daily doses of unweighted UV-B and UV-BBE radiation. The concentrations of chlorophylls a and b were apparently unaffected by O3 depletion. The data derived from this study suggest that changes to the radiative environment associated with stratospheric O3 depletion influence the pigmentation of A. regularis. As a corollary, flavonoids are shown to be present in tissues of A. regularis.