Caldwell, M.M., R. Robberecht, R.S. Nowak, and W.D. Billings. 1982. Differential photosynthetic inhibition by ultraviolet radiation in species from the arctic-alpine life zone. Arctic and Alpine Research 14:195-202.
Abstract. Inhibition of photosynthesis and epidermal damage
resulting from ultraviolet irradiation were assessed for arctic
and alpine plant species. These species were taken from a latitudinal
gradient of the arctic-alpine life zone from the Andes to northern
Alaska, which spans a steep change in solar UV-B irradiation (280
to 320 nm). Ecotypes and species from the Arctic, where solar
UV-B flux is very low, were consistently more sensitive to UV
radiation than their counterparts from lower latitude alpine regions,
where solar UV-B flux is high. Most of the species did not display
a change in UV-radiation sensitivity following a 2-wk pretreatment
at elevated UV-B irradiance. The difference in photosynthetic
inhibition caused by UV irradiation of arctic and alpine ecotypes
of Oxyria digyna could not be attributed solely to differences
in UV flux penetrating to mesophyll tissues. Further, arctic
ecotypes exhibited short-term fluorescence transients indicating
damage to the oxidizing side of Photosystem II in the photosynthetic
light reaction, whereas there was no indication of this for alpine
ecotypes. Thus, there appear to be inherent qualitative and quantitative
differences in the UV-radiation sensitivity of photosynthetic
systems in arctic and alpine ecotypes.
This research was supported by grants from the United States National Science Foundation (DEB 76-22381), the Environmental Protection Agency, and the National Aeronautics and Space Administration.