The phytotoxic effect of C1/C2-halocarbons and trichloroacetic acid on the steppe plant Artemisia lerchiana

Artemisia lerchiana is a wormwood species of the Central Asian steppe regions, where it completely cover whole areas. For the first time it was possible to show through field experiments that C1/C2 halocarbons (VCHCs), such as chloroform (CHL), tetrachloroethene (PER) and hexachloroethane (HEX), can be taken up by test plants of the species A. lerchiana via the soil/root pathway and metabolised inter alia into trichloroacetic acid (TCA) under semi-aride conditions. At the same time, chlorophyll a fluorescence measurements carried out on the test plants revealed a phytotoxic influence on plant vitality (max. decline in vitality of 52% with application of CHL) and less efficient energy flows in the photosynthesis mechanism of the A. lerchiana test plants. The authors examine possible links between the simultaneous appearance of VCHCs and additional drought stress in the acceleration of desertification processes.