An experimental comparison of aluminium and manganese susceptibility in Antennaria dioica, Arnica montana, Viola canina, Filago minima and Deschampsia flexuosa

Antennaria dioica, Arnica montana, Viola canina and Filago minima are declining in The Netherlands and are even locally extinct. This process of decline has been associated with an increased rate of acidification of soils and an increased availability of aluminium and manganese to plants up to potentially phytotoxic levels. This paper examines whether, and to what extent, aluminium and manganese are important environmental variables in determining the decline in plant species. Susceptibility to ionic aluminium and manganese was studied in three experiments under controlled conditions. Young plants were grown on a complete nutrient solution containing variable concentrations of aluminium, manganese or aluminium plus manganese (pH 3·8). Responses (dry weights after 5 weeks of growth) were compared to those of Deschampsia flexuosa , known to be aluminium and manganese resistant