Sensitivity to UV-B of Plants Growing in Different Altitudes in the Alps

Abstract

The purpose of our investigations was to elucidate whether different species of the same genus growing preferentially in different altitudes have a genetically fixed different sensitivity to ultraviolet B (UV-B, 280–320 nm), possibly by selection, and/or whether they have a different ability to adapt to UV-B. Plants from species pairs or triplets of 5 genera were grown from seeds without or with additional UV-B. Sensitivity was tested in a growth chamber with UV-B-irradiation in addition to white light by estimation of visible injury. Content and accumulation of UV-absorbing compounds were measured from leaf extracts. In plants grown without UV-B to a cushion there were marked differences in the sensitivity to UV-B between different genera. Different species of the same genus showed only slight differences in sensitivity but in 2 genera the alpine species exhibited a better adaptation after UV-B pre-irradiation. UV-B enhanced the accumulation of UV-absorbing substances to different amounts. Marked differences in the sensitivity to UV-B between different genera may lead to a change in ecosystems should the natural UV-B-radiation increase.