Effects of low ozone concentrations on growth of Betula pubescens Ehrh., Betula verrucosa Ehrh. and Alnus incana (L.) Moench

summary Seedlings of Betula pubescens, Betula verrucosa and Alnus incana were grown for 50 days in growth chambers at four ozone concentrations (25, 35, 53 and 82 nl 1 −1 ) fot 7 h day −1 . Shoot and root dry weight decreased almost linearly with increasing ozone concentration in the three species. Shoot/root and leaf/stem dry weight ratios were unaffected by ozone concentration, while leaf senescence was significantly enhanced by increasing the concentration. Visible ozone injury was observed at 53 nl 1 −1 and above.