|Pursley, Walter - NC STATE UNIVERSITY|
Submitted to: Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 15, 2002
Publication Date: September 1, 2003
Citation: Heagle, A.S., Miller, J.E., Pursley, W.A. 2003. Growth and yield responses of solanum tuberosum to mixtures of carbon dioxide and ozone. Environmental Quality. 32:1603-1610. Interpretive Summary: Elevated carbon dioxide (CO2) concentrations can stimulate plant growth and yield, whereas ground-level ozone (O3) concentrations are high enough to suppress plant growth and yield in many areas of the world. Both of these gases exist together in the air, so an understanding of how mixtures of O3 and CO2 affect crop yield is needed to improve estimates of future food supply. Recent experiments show that elevated CO2 often protects plants from damage caused by O3, but this has not been adequately tested for many important crops such as Irish potato. An O3-resistant and an O3-sensitive potato cultivar were exposed from emergence to maturity to mixtures of O3 and CO2 in open-top field chambers. Elevated CO2 increased growth and tuber yield of both cultivars, whereas elevated O3 generally suppressed growth and yield, mainly of the sensitive cultivar. Elevated CO2 appeared to protect the sensitive cultivar from O3-induced suppression of shoot, root and tuber weight as measured at mid-season but did not protect either cultivar from O3 stress at the final harvest. The results show that the effects of O3 + CO2 mixtures on a given crop cannot be predicted by knowing effects of the individual gases.
Technical Abstract: Recent experiments show that elevated CO2 protects some plants from O3 stress, but this has not been adequately tested for many important food crops including Irish potato (Solanum tuberosum L.). A field experiment was performed to determine if elevated CO2 can prevent damage to potato caused by high concentrations of O3. An O3-resistant cultivar (Superior) and an O3-sensitive cultivar (Dark Red Norland) were exposed to mixtures of CO2 and O3 from 10 days after emergence to maturity in open-top chambers. The three CO2 treatments were 366 µL L-1 (ambient), 540 and 715 and µL L-1. The three O3 treatments were charcoal-filtered air (15 nL L-1), nonfiltered air (45 nL L-1) and nonfiltered air with O3 added for 12h d-1 (80 nL L-1). Elevated O3 and CO2 caused extensive foliar injury of Dark Red Norland but caused only slight injury of Superior. Elevated CO2 increased growth and tuber yield of both cultivars, whereas elevated O3 generally suppressed growth and yield, mainly of Dark Red Norland. Elevated CO2 appeared to protect Dark Red Norland from O3-induced suppression of shoot, root and tuber weight as measured at mid-season but did not protect either cultivar from O3 stress at the final harvest.