DIFFERENTIAL RESPONSES OF ALPINE AND NON-ALPINE AQUILEGIA SPECIES TO INCREASED ULTRAVIOLET-B RADIATION

Two species of columbines, Aquilegia caerulea (which lives in alpine environments) and A. canadensis (a lower-elevation species) responded to artificially increased levels of solar UV-B radiation by becoming significantly shorter and developing a significantly greater number of leaves. The degree of shortening was greater in A. canadensis, the nonalpine species, while the number of leaves increased faster in A. caerulea. Significant differences in gas-handling and water-use physiological responses were noted, with UV-B treatment leading to decreased water-use efficiency in both species. Concentrations of flavonoids increased significantly in both species following light exposure, whereas alkaloids in A. caerulea appeared to be destroyed by UV-B. No significant changes occurred in beta-carotene concentrations in either species.