Tissue extracts from 2‐month‐old PDR1 OE leaves and stems did not cause any germination of parasitic weeds in three attempts, probably because of low SL concentrations in adult shoots. However, two attempts with one order of magnitude lower dilutions of leaf extracts (see Methods S1) provided germination rates of between 1% and 4% (Fig. 5a). These results confirmed that SL concentrations in PDR1 OE shoots are lower than in the wild‐type, surprisingly also in stems where bud outgrowth is inhibited (Sasse et al., 2015). By contrast, the same experimental setup with extracts from pdr1 ko leaves showed a higher germination rate than in the wild‐type (Fig. S3a), suggesting that PDR1 is necessary for transporting SLs out of the leaf.