Analysis of Pi uptake rate and Pi translocation in the cax1/cax3 mutant. A and B, The uptake rate of [33P]Pi in wild-type (WT), cax1, cax3, cax1/cax3, and pho2 plants grown under ±Pi (250 μm KH2PO4; A) or −Pi (10 μm KH2PO4; B) conditions. C and D, The shoot-to-root ratio of [33P]Pi accumulation during the transport period under +Pi (C) or −Pi (D) conditions. Values represent means ± sd of three biological replicates. Data significantly different from the corresponding wild-type controls are indicated (* P < 0.05, ** P < 0.01; Student’s t test). FW, Fresh weight.