| MS Description
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Frozen Arabidopsis leaves were homogenized … Frozen Arabidopsis leaves were homogenized in extraction solvent (methanol: H2O = 4:1) with 5 μl of solvent/mg of fresh weight in a mixer mill (MM300; Retsch GmbH & Co. KG) for 3 min at 30 Hz. After centrifugation at 12,000 × g for 10 min, cell debris was discarded, and supernatants were recentrifuged. The resultant supernatants were immediately analyzed with a Waters Acquity UPLC system (Waters Corp.) fitted with a Q-TOF Premier mass spectrometer (Micromass MS Technologies). A 2-μl sample was applied to an ACQUITY UPLC BEH C18 column (Φ2.1 × 100 mm, 1.7 μm, Waters) at a flow rate of 0.5 ml/min with linear gradients of solvent A (0.1% formic acid in H2O) and solvent B (0.1% formic acid in methanol) set according to the following profile: 0 min, 95% solvent A +5% solvent B; 9 min, 60% solvent A + 40% solvent B; 11 min, 100% solvent B; 13 min, 95% solvent A +5% solvent B. The column temperature was 35 °C. Photodiode array (PDA) was used for detection of UV-visible absorption in the range of 210–500 nm. Electrospray ionization (ESI) with positive mode was used. The TOF mass analyzer was used for detection of flavonoid glycosides [M+H]+ and fragment ion peak in a positive ion mode scanning with the following setting; desolvation temperature was 450 °C at a nitrogen gas flow rate of 600 liters/h, capillary spray 3.2 kV, source temperature 150 °C, and cone voltage 35 V. temperature 150 °C, and cone voltage 35 V.
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