Correlation between genotypes, soils and Pi uptake in Petunia hybrida W115 and PDR1 OE plants. (a–c) FW (root and shoot) on full soil, clay and clay+ 8 wk after germination (wag). (d–g) Representative shoots of W115 and PDR1 OE plants grown on clay (−myc) and clay+ (+myc). Bars, 2 cm. Values are means ± SE. *, P < 0.05; **, P < 0.005.