The effects of long-term open-air fumigation with SO on a field crop of broad bean (Vicia faba L.) II Effects on growth components, leaf area development and elemental composition.

Faba bean crops (Vicia faba L.) were exposed to elevated SO concentrations in three different years in an open-air field exposure system for the controlled release of air pollutants. The treated crops were exposed to an average SO, concentration of 165μg m in 1985, 62μg m in 1986 and 74μg m in 1988. The ambient SO concentration was about 10 μg m . Plant height, number of internodes and number of pods were not affected by SO . The specific leaf area was reduced in the plants exposed to SO at the end of the growing season. Leaf area development was strongly affected during the pod-filling period in 1985 and 1988 as a result of leaf injury and defoliation in the fumigated plots. In 1986 a similar trend in leaf area reduction was observed in the early reproductive phase. N and Mg content of the different organs was unaffected by SO . The S content was strongly elevated in the leaves and pods of the fumigated plants, and the Ca content of the leaves was reduced by SO . Chlorophyll content of different leaf numbers was unaffected by SO .