On clay+, neither wild‐type nor PDR1 OE plants showed lateral shoot growth during the first 8 wag (Fig. 2d–g), probably because of the limiting nutrient conditions, and therefore the higher biomass production of PDR1 OE plants is given by main stem and leaves. Interestingly, the main stem and leaves also account for the equal shoot biomass production on full soil (Fig. 2a), where wild‐type plants exhibit a stronger branching compared with PDR1 OE, as previously published (Sasse et al., 2015). We then analyzed in detail the shoot morphology of PDR1 OE on full soil, and we scored larger and rounder foliage surface and thicker stems in PDR1 OE than in the wild‐type (Fig. 3a–d). The leaf length : width ratio in PDR1 OE leaves was smaller than in the wild‐type (Fig. 3e). Epidermal cells in PDR1 OE leaves (middle blade) were larger than in the wild‐type (Fig. 3f,g).