Contribution No. 2348 from Central Research and Development Department, Experimental Station, E. I. du Pont de Nemours and Company, Wilmington, Delaware 19898. treatment, control (solvent-treated) and treated pots were placed in two dark chambers. One chamber was purged with air at 15 liters/min, while the other was purged at the same flow rate with 0.25 pl/liter of ethylene.