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INTERACTIVE EFFECTS OF ELEVATED CO2 AND 03 ON RICE AND FLACCA TOMATO
Citation:
Olszyk, D. AND C. Wise. INTERACTIVE EFFECTS OF ELEVATED CO2 AND 03 ON RICE AND FLACCA TOMATO. Agriculture Ecosystems and Environment 66(1):1-10, (1997).
Description:
All atmospheric concentrations of both carbon dioxide (CO2) and ozone (03) are increasing, with potentially dramatic effects on plants. This study was conducted to determine interactive effects of CO2 and 03 on rice (Oryza sativa L. cv. IR 74) and a 'wilty' mutant of tomato (Lycopersicon esculentum Mill. flacca). Plants were grown from seed in a glasshouse and exposed for 28 days to ambient or elevated CO2(apprxeq400 or 700 mul 1-1 CO2)and/or ambient or elevated 03 (peak/valley pattern of exposure with cumulative totals of apprxeq 1 or 44 mul 1-1 h). Elevated CO2 alleviated 03-associated decreases in allocation of biomass to roots, as indicated by a decreased root:shoot ratio (p<0.05), and also reduced injury from 03 as indicated by leaf greenness readings for one experiment (p<05.05). By itself, elevated CO2 resulted in increases in total plant and individual organ(root, leaf, stem) dry weights and root:shoot ratio; and elevated 03 resulted in increases in main culm leaf number and a decrease in stem dry weight(p<0.05). Elevated CO2 had no significant effect on the tendency for 03-induced biomass reductions of flacca tomato. For flacca, elevated CO2 alone increased shoot and root biomass (p<0.05), and elevated 03 alone tended to decrease biomass for both parameters, but only at p=0.09 and 0.11, respectively. This study was preliminary, as the environmental conditions in these experiments may have altered 03 and CO2 responses of the plants. However, these results provided additional evidence that elevated CO2 inhibits adverse effects of 03 on plants, and that the interactive response may be mediated by stomata.