Sequential reduction of UV-B radiation in the field alters the pigmentation of an Antarctic leafy liverwort.

Abstract

UV-B radiation (280–315 nm), incident on the leafy liverwort Cephaloziella varians growing at Rothera Point on the Western Antarctic Peninsula, was manipulated in late austral spring 1998 by screens consisting of a novel combination of Plexiglas panes and polyester sheets. The screens transmitted approximately 79, 68, 48, 41 and 31% of daily UV-B radiation dose. Plants from under and outside the screens were sampled seven times over 35 days.

Correlative analyses indicated that concentrations of an anthocyanin-like pigment located in leaf tips were positively associated with UV-B transmission at the last two samplings, that concentrations of total chlorophylls were negatively associated with UV-B transmission at the final sampling, and that those of UV-B screening pigments were positively correlated with transmission at three intermediate samplings. Plants exposed to low UV-B transmission levels were visibly greener than those exposed to high transmission levels after approximately 23 days.

The closest relationships between the treatment and concentrations of UV-B screening pigments were associated with increased ambient biologically weighted UV-B dose received by plants in the 5.5 h before each sampling, which coincided with the passage of the ozone hole over Rothera Point. As C. varians emerged from melting snow and ice, concentrations of the anthocyanin-like pigment and chlorophyll respectively increased and decreased faster in plants exposed to high transmission levels of UV-B, relative to those exposed to low UV-B transmission levels.

Citation

Newsham, K.K., Geissler, P.A., Nicolson, M.J., Peat, H.J. and Lewis-Smith, R.I., 2005. Sequential reduction of UV-B radiation in the field alters the pigmentation of an Antarctic leafy liverwort. Environmental and experimental botany, 54(1), pp.22-32.

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