To test if altered SL allocations in PDR1 OE shoots are responsible for the observed phenotypes, we assayed SL‐inducible germination of the parasitic weed Phelipanche ramosa using P. hybrida shoot extracts from 1‐month‐old PDR1 OE plantlets, where leaves represent 87% (± 3.5%; n = 5) of the shoot biomass and no lateral buds are formed yet. The germination of Phelipanche ramosa seeds is very sensitive to SLs (up to four orders of magnitude higher than mass spectrometer detection limit; see Guillotin et al., 2017). However, it can be induced not only by SLs but also by isothiocyanates (Auger et al., 2012), present almost exclusively in Brassicaceae (Halkier & Gershenzon, 2006). Still, we tested for the presence of possible inhibitors or activators in our plant extracts. The germination ability of GR24 was assayed ± wild‐type, pdr1 ko and PDR1 OE extracts. In none of the analyzed cases could the negative effect of unknown molecules in the extracts from P. hybrida tissues override the results we scored with pure extracts (Fig. S2a,b). This bioassay operated with PDR1 OE plantlets showed that PDR1 OE leaves contain lower concentrations of SL than the wild‐type (Fig. 3h). By contrast, increased PDR1 OE stem thickness was compatible with SL‐induced cell division in the procambium, as reported in A. thaliana after exogenous GR24 treatments (Agusti et al., 2011). PDR1 OE stems also had longer internodes than those of the wild‐type; with or without mycorrhizal fungi in the soil (Fig. 3i) PDR1 OE internodes were 1.5‐ to two‐fold longer than in the wild‐type. As SL was reported to increase internode elongation in Pisum sativum (de Saint Germain et al., 2013), we propose that this phenotype in P. hybrida is a result of increased SL transport within/towards the procambium.