Effects of elevated CO 2 and O 3 on tuber quality in potato ( Solanum tuberosum L.)

Abstract

This study examined the effects of season-long exposure to elevated carbon dioxide (CO 2) and/or ozone (O 3) on tuber quality in potato ( Solanum tuberosum L. cv. ‘Bintje’). Stands of potato were grown to maturity in open-top chambers (OTCs) in 1998 and 1999 under a factorial combination of three CO 2 (ambient, 550 and 680 μmol mol −1) and two O 3 levels (ambient and elevated; 8 h per day seasonal means of 50 and 65 nmol mol −1 in 1998 and 1999, respectively). The intermediate CO 2 concentration was omitted from analysis of tuber quality. In 1999, the starch content of tubers and the viscosity of the resulting paste were increased by elevated CO 2 ( P<0.05). Tuber nitrogen content was reduced by elevated CO 2 in both years ( P<0.05), but nitrate content was decreased only in 1999 ( P<0.05). Elevated CO 2 reduced citric acid content in 1998 ( P<0.05) and increased Vitamin C content in 1999 ( P<0.05). Elevated CO 2 also tended to decrease the total glycoalkaloid content of tubers ( P<0.08) by decreasing their α-chaconine content. Elevated O 3 had less marked effects on tuber quality even though AOT40 values (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 glycoalkaloid content was increased in 1999 because of an increase in α-solanine content ( P<0.05). No CO 2×O 3 interactions were detected for any of the quality parameters examined. The results are discussed in the context of the likely effects of predicted changes in climatic conditions on tuber quality.