Effects of elevated CO2 and O-3 on tuber quality in potato (Solanum tuberosum L.)

This study examined the effects of season-long exposure to elevated carbon dioxide (CO2) and/or ozone (O-3) on tuber quality in potato (Solanum tubero sum L. cv. 'Bintje'). Stands of potato were grown to maturity in open-top c hambers (OTCs) in 1998 and 1999 under a factorial combination of three CO2 (ambient, 550 and 680 mu mol mol(-1)) and two O-3 levels (ambient and eleva ted; 8 h per day seasonal means of 50 and 65 nmol mol(-1) in 1998 and 1999, respectively). The intermediate CO2 concentration was omitted from analysi s of tuber quality. In 1999, the starch content of tubers and the viscosity of the resulting paste were increased by elevated CO2 (P < 0.05). Tuber ni trogen content was reduced by elevated CO2 in both years (P < 0.05), but ni trate content was decreased only in 1999 (P < 0.05). Elevated CO2 reduced c itric acid content in 1998 (P < 0.05) and increased Vitamin C content in 19 99 (P < 0.05). Elevated CO2 also tended to decrease the total glycoalkaloid content of tubers (P < 0.08) by decreasing their alpha -chaconine content. Elevated O-3 had less marked effects on tuber quality even though AOT40 va lues (accumulated O-3 exposure above a threshold of 40 nmol mol(-1)) of 12, 461 and 27,113 nmol mol(-1) h were applied in 1998 and 1999, respectively. In 1998 the paste produced from tubers produced under elevated O-3 was more viscous (P < 0.05) and in 1999 the starch granules were less resistant to swelling (P < 0.05) than in tubers produced under ambient O-3. Total glycoa lkaloid content was increased in 1999 because of an increase in a-solanine content (P < 0.05). No CO2 x O-3 interactions were detected for any of the quality parameters examined. The results are discussed in the context of th e likely effects of predicted changes in climatic conditions on tuber quali ty. (C) 2001 Elsevier Science B.V. All rights reserved.