Methylcyclopentadienyl manganese tricarbonyl (MMT), plant uptake and effects on metabolism

In the USA and Canada, methylcyclopentadienyl manganese (MMT) is currently added to gasoline to replace tetraethyl lead as an antiknock fuel additive. Manganese concentrations in roadside soil and plants are increasing and co rrelated with distance from the roadway, traffic volume, plant type, and mi crohabitat. Radish (Raphanus sativus L.) seedlings were treated for either five or thirty-five days with different levels of manganous chloride (0-100 0 ppm). Metabolic heat rates (q) and respiration rates (R-CO2), measured ca lorimetrically, indicated severe stress at Mn concentrations between 10 and 100 ppm and at temperatures above 20 degrees C. Predicted growth rates (R- SG) also decreased in these circumstances. (C) 2000 Elsevier Science B.V. A ll rights reserved.