Effects of Ionized AIr and Ozone on Plants

Using polonium on copper foil as an ionizing agent for air, which was then passed over the plant material, MIDDLETON (16), WHIMSTER (29), VAN ASPEREN DE BOER (28) and PORTSMOUTH (19), obtained contradictory results. MIDDLETON found an increase in respiration varying from 5.58 2.57 to 29.11 5.62 per cent. PORTSMOUTH, attempting to dupli- cate MIDDLETON'S results with barley seedlings, got no significant increase in one experiment, and only 1.5 per cent. in another. Again, WHIMSTER found an increase as high as 85.7 7.1 per cent. in respiration of Pelar- gonium leaves, while PORTSMOUTH with a similar experimental setup obtained no sign of the increase found by WHIMSTER. Likewise VAN ASPEREN DE BOER found no effect of ionized air on the respiration of fungi.