Cucumber (Cucumus sativus) seedlings were grown from germination under intermittent sulphur dioxide (SO 2 ) fumigation in naturally lit growth cabinets. Average cabinet temperature minima ranged from 12.7 to 14.1 o C, while maxima varied from 28.7 to 32.0 o C. Fumigation of SO 2 for 8 h per day, 4 days per week, for 4 weeks at 0.1, 0.2 and 0.5 ppm reduced leaf area by 13.5, 46.7 and 45.1% and plant dry weight by 15.5, 55.4 and 58.6%, respectively. However, when plant growth was described as a function of accumulated degree days, no effect of 0.1 ppm SO 2 was observed. Under 0.5 ppm SO 2 , specific leaf area was reduced and more assimilate was partitioned to the shoots at the expense of the roots. The application of these data to the assessment of possible crop losses in a tropical environment is discussed.