Changes in root starch contents of mature beech (Fagus sylvatica L.) along an ozone and nitrogen gradient in Switzerland

Ozone and nitrogen deposition as anthropogenic pollution factors have been shown to affect carbon partitioning in plants. Both pollution factors have increased in recent decades, frequently exceeding the critical levels and loads for forests. Therefore, root starch contents of Fagus sylvatica L. were determined along an ozone and nitrogen gradient in Switzerland at 20 forest sites of mature trees. The starch contents were analyzed enzymatically. We found a negative correlation for the root starch contents with ozone and nitrogen, with an antagonistic interaction term, indicating that one pollution factor might alleviate the effect of the other.