THE EFFECT OF ELEVATED UV-B (280-320 NM) RADIATION-LEVELS ON SILENE VULGARIS - A COMPARISON BETWEEN A HIGHLAND AND A LOWLAND POPULATION

Highland (altitude 1600 m above sea level) and lowland (altitude -2 m below sea level) populations of the perennial herb Silene vulgaris (Mo ench) Garcke, were tested on their response to elevated levels of UV-B radiation. Highland populations typically receive high natural UV-B f luxes, whereas lowland populations receive a lower natural UV-B dose. Adaptation to high UV-B levels of the highland population is to be exp ected. Experimental comparison of growth rates, gas exchange rates, tr anspiration and biochemical parameters using adult plants as well as s eedlings did not show a difference in the response to elevated UV-B le vels between the two populations. Individuals of both populations were relatively insensitive to elevated UV-B radiation. The response of al pine and lowland populations of Silene vulgaris is discussed in relati on to the dispersal of this species after the last ice age.