EFFECTS OF AIR FILTRATION ON SPRING WHEAT GROWN IN OPEN-TOP FIELD CHAMBERS AT A RURAL SITE .1. EFFECT ON GROWTH, YIELD AND DRY-MATTER PARTITIONING

Spring wheat, Triticum aestivum, was grown in open-top field chambers and exposed during the whole life cycle to filtered and non-filtered ambient air. The relatively low ambient pollution level did affect plant growth but had no effect on the overall grain yield of the two spring wheat cultivars Echo (1987) and Pelican (1988). A reduced root growth was found in both years which could be attributed mainly to the deposition of NO2 and SO2. Effects on crop development most likely due to ozone were limited to the 1987 growing season during which the ambient ozone concentrations were enhanced compared to 1980. This resulted in a slightly increased grain harvest index. a reduced 1000-grain weight, straw yield and a greater reduction in root growth. Visible damage resembling ozone injury appeared both years during seedling growth.