Fig. 6.

Average (+SE) elicitation rate of monoterpenes in mature leaves of 10-12 weeks old N. tabacum ‘Wisconsin’ at 0.5, 10, and 48 hours of recovery after ozone exposure at 0, 400, 600, 800, and 1000 ppb for 30 min in a custom-made cylindrical double-walled glass chamber at 25 °C. The elicitation rate of emissions is defined as the rate of change of emission (positive values indicate an increase of the rate and negative values a decrease of the rate). Data are averages of three independent replicates. Individual effects of ozone, recovery time (Time), and their interactions on emission rates were tested by GLM with maximum likelihood model fitting. Wald chi-square (χ²) test statistics and statistical significance are indicated as: * - P < 0.05, ** - P < 0.01, *** - P < 0.001.