UV-B and UV-A induced DNA damage in field grown plants

SZWARCBERG-BRACCHITTA M.; GIORDANO C. V.; ROUSSEAUX M. C.; ZIMA A. M.; MAZZA C. A.; SCOPEL A. L.; BALLARÉ C. L.

Madison, USA

Congreso; Annual Meeting of the American Society of Plant Physiologysts; 1998

An important issue in the prediction of plant responses to UVB changes resulting from stratospheric ozone variations is to establish which responses occur in plants grown in the field and what is the relative contribution of UVB and UVA in the induction of these responses. We measured cyclobutane pyrimidine dimers (CPDs) in DNA extracted from leaf tissue of barley plants grown in Buenos Aires (34 deg. SL) and from Gunnera magellanica plants that occur naturally in Tierra del Fuego (southern Argentina), an area of the globe that is frequently under the Antarctic ozone hole in the spring. Leaf tissue of both plants had detectable DNA damage in spite of the large constitutive (G. magellanica) and UVB-induced (barley) level of UV-absorbing sunscreens. Filtration experiments indicated that the UVB component received at both locations in early spring induces measurable DNA damage in barley and G. magellanica. However, plants grown with the solar UVB component excluded still had significant quantities of DNA damage, which could be lowered by photorepair. Parallel UVA-filtration experiments indicated that the UVA component causes a significant fraction of the total DNA damage under field conditions (at least 50 % in G. magellanica).