Carbon dioxide concentrates in containers are frequently controlled by using a diethanolamine-bicarbonate buffer. Current studies show that this buffer produces ethylene and that the production increases with increasing pH and/or time in the incubation vessel. Ethylene is not produced when 3-amino-1-propanol is used instead of diethanolamine in the buffer solution. The modifier buffer is equally or more effective in contolling the CO2 concentrations around plants incubated in the light or dark than the diethanolamine buffer.