Effects of the overexpression of SlHAK10 on tomato growth and K+ acquisition under a sand-based pot culture condition. For 35S-OE, SlHAK10 was overexpressed under the control of the constitutive CaMV35S promoter; for pPT4-OE, SlHAK10 was overexpressed under the control of the mycorrhiza-specific Pi transporter promoter pSmPT4. Two-week-old seedlings were grown in sand-based pot culture for AM fungal inoculation for 5 weeks. The plants were treated with either high-K+ (2 mm K+) or low-K+ (0.2 mm K+) solution. AM, Mycorrhizal plants; DW, dry weight; NM, nonmycorrhizal plants. A and B, Total biomass. C and D, K+ concentration in shoots. E and F, K+ concentration in roots. Error bars indicate se (n = 5). The asterisks indicate significant differences (P < 0.05).