A field fumigation system was modified from one described earlier (Reich et al., 1982) and used to expose unenclosed field-grown soybean plants Glycine max cv Hark to low levels of O3 and/or SO2. A 3 × 3 factorial design was employed, allowing for analysis of individual effects of and potential interactions between the two pollutants. During the experiment ambient O3 was significant, but low (mean concentration of 0·04 μl litre-1), and ambient SO2 were not detected. Plants were exposed to ambient air with or without additional pollutants for about 5 h per day on 16 days between 20 August and 12 September, 1980. Exposure to greater than ambient levels of O3 (mean concentration of 0·06 or 0·08 μl litre-1) caused significant linear reductions of 2-5% in mass per seed and number of seeds per pod, 17-25% in number of seeds and pods per plant and 10-25% in seed yield (dry mass) per plant and per hectare. Exposure to greater than ambient levels of SO2 (mean concentration of 0·06 or 0·11 μl litre-1) caused significant linear reductions of 4-7% in mass per seed. High SO2 treatment (mean concentration of 0·11 μl litre-1) also resulted in non-significant declines of 7-12% in yield per plant and per hectare. no significant interactions between the pollutants were observed and O3 had a severalfold greater impact on soybean than SO2 on either a concentration or a dose basis.
|Original language||English (US)|
|Number of pages||11|
|Journal||Environmental Pollution. Series A, Ecological and Biological|
|State||Published - 1984|