ELEVATED CO2 AND THE MINERAL-CONTENT OF HERBACEOUS AND WOODY-PLANTS

The CO2 enrichment effects (300-650 mumol mol-1) on mineral concentration (N, P, K, Ca, Mg, Mn, Fe, Zn), absolute total mineral contents per individual and of whole stands of four herbaceous (Trifolium repens L., Trifolium pratense L., Lolium perenne L., Festuca pratensis HUDS.) and two woody species (Acer pseudo-platanus L., Fagus sylvatica L.) were investigated. In general, the mineral concentration of the plant tissues decreased (all six species: N > Ca > K > Mg) with the exception of P. Mn and Fe were only determined for the tree species. Both decreased in concentration (Mn > Fe). Zn was only analysed for Trifolium pratense and Festuca pratensis and decreased significantly in the grass. Despite of decreases in concentrations of as much as 20 % in some cases there were increases in absolute amounts per individual and, therefore, in the whole vegetation up to 25 % because of the enhanced dry matter accumulation at elevated CO2 supply.