Impact of different K⁺ applications and AM fungal colonization on tomato plant growth and K⁺ acquisition. A and B, Shoot (A) and root (B) biomass of AM and NM plants. C and D, K⁺ accumulation in shoots (C) and roots (D) of AM and NM plants. E and F, Total colonization rate (E) and arbuscule abundance (F) under high-/low-K⁺ supply conditions. AM, AM fungus-colonized plants; NM, nonmycorrhizal plants. Error bars indicate se (n = 5). Asterisks indicate significant differences (P < 0.05).