SOLUBLE CARBOHYDRATES AND SECONDARY PHYTOCHEMICALS IN BETULA AS AFFECTED BY SO2-POLLUTION

Seedlings of closely related birch species Betula pendula and B. resin ifera, which have moderate similarity in their phytochemical compositi on, were exposed to a SO2 concentration of 200 mu g m(-3) for 24 days to detect their sensitivity and possible induced changes in the amount of primary and secondary phytochemicals. The species deviated from ea ch other in the production of biomass and phytochemicals. The SO2 poll ution induced no changes in growth nor in the soluble sugar concentrat ions in the species. However, the chromatographic analyses showed the moderate reduction in the amount of antioxidative and defensive phenol ics, i.e. myricitrin, (+)-catechin, 3,4'-dihydroxypropiophenone and pr oanthocyanidins in both birch species. These results indicate more pro nounced sensitivity of secondary metabolism to SO2 pollution compared with primary metabolism, and the reduced tolerance of birches to other oxidative air pollutants as well as to herbivores in polluted environ ments.