Figure 1

HPLC traces of plant phloem exudates obtained by aphid stylectomy. Stylets were excised from aphids feeding on Hordeum vulgare (barley) (B), Pisum sativum (pea) (C), Solanum tuberosum (potato) (D), Nicotiana tabacum (tobacco) (E) and Brassica rapa ssp. Oleifera (turnip) (F) using a microcautery device. The exuded phloem sap was collected and diluted into ice-cold 5% H₃PO₃ containing 5 mM TCEP. The figure shows chromatograms (A₂₄₅) of phloem exudates and insets show the absorbance spectrum from the left and right sides of the peak with identical retention time to authentic AsA (A). The horizontal axis represents retention time (min) and the vertical axis detector response (milli-absorbance units).