Fig. 5. Effects of cultivar (Ctr), paraquat-induced oxidation (Pq), and time of observation on the ethylene production rate in wheat seedlings. Means ± SD of two replications are presented. Arrow indicates application of additional light to 400 µmol m^–2 s^–1 photosynthetic photon flux density. Probabilities for cultivar effect and cultivar x treatment interaction (in parentheses) are presented at the left top of the figure. DW = dry weight.