Effects of ozone and sulfur dioxide on tuber yield and quality of potatoes

Air pollution injury of the potato plant (Solanum tuberosum L.) has been documented previously, but potato yield losses have not been estimated in replicated experiments having controlled exposures to ozone (O/sub 3/) and sulfur dioxide (SO/sub 2/). A controlled-environment study involving the speckle-leaf-sensitive cultivar 'Centennial Russet' was conducted to examine the effects of chronic exposure to O/sub 3/ and SO/sub 2/ on plant growth and tuber yield and quality. Ozone, at the highest seasonal dose (44.2 ppm-h), reduced leaf dry weight 48%, root dry weight 58%, tuber number 38%, and total tuber yield 45%. Lower exposures affected these parameters in linear proportion to the O/sub 3/ dose. Mean stem (minus leaves) dry weight, tuber dry weight, tuber dry matter percentage, partitioning of dry matter to tubers, and tuber sugar concentrations were not affected. Tuber N concentration increased linearly by up to 21% as the O/sub 3/ dose increased. Plants grown outside of chambers in ambient air showed effects consistent with results obtained within the chambers. The plants grown outside received a total seasonal O/sub 3/ dose of 50.4 ppm-h and produced 58% less tuber yield than filtered air control plants.Plant responses to SO/sub 2/ exposure were much less pronounced thanmore » their responses to exposure to O/sub 3/. However, leaf symptom development in O/sub 3/-treated plants was markedly intensified by the presence of SO/sub 2/. Small reductions in tuber yield and mean tuber size, but not in tuber number, were observed in SO/sub 2/-treated plants. Tuber N concentration increased slightly in SO/sub 2/-treated plants. A significant O/sub 3/ X SO/sub 2/ interaction was observed in the case of tuber N concentration only; SO/sub 2/ accentuated the O/sub 3/-induced increase in N content.« less