The leaf from each plant was collected separately and quick-frozen in liquid N2. Frozen samples were ground under liquid N2 with a mortar and pestle. A total of 50mg of the resulting powder was first extracted and twice reextracted with methanol:isopropanol:acetic acid (20:79:1, v/v/v) (Müller and Munné-Bosch, 2011). The extracted samples were quantified according to Segarra et al. (2006), using the following transitions: 137/93, 263/153 and 209/59 for SA, ABA and JA, respectively.