Changes in the concentration of IAA and IAA-Asp in pre-veraison berries in response to Ethrel application. IAA (A, C) and the IAA-amino acid conjugate, IAA-Asp, (B, D) were quantified by LC-MS/MS in pre-veraison Shiraz berries from the 2011 trial (A, B) and the 2012 trial (C, D) at the indicated time points after treatment with a Control or Ethrel solution as described in Figure 1. Control, dark grey bars; Ethrel, light grey bars. FW, fresh weight. CV, veraison of Control fruit; EV, veraison of Ethrel-treated fruit. All data represent means ± SE (n = 3). Asterisks indicate significant differences of the mean values of Ethrel-treated samples from the mean values of Control samples as determined with Student’s t-test (*p < 0.05, ***p < 0.001).