Figure 2.

Impact of aphid infestation on apoplastic AO activity in tobacco leaves. Wild-type (WT), PAO, and TAO tobacco plants were grown for 6 weeks in the absence of aphids. At the end of the 6-week period, one group of plants was infested with a single 1-d-old nymph while the remaining group was left in the absence of aphids and grown in cages for a further 2 weeks as described. At the end of the 2-week period, plants were harvested and apoplastic AO activity was quantified as described (A). Bars illustrate mean AO activity ± se (n = 6), and different letters above the bars indicate values that were significantly different from one another according to Fisher’s protected lsd test. A linear relationship was observed between measured AO activity and aphid fecundity (B). FW, Fresh weight.