Table 1. Transport Mechanism and energetics in plant AMTs.

Organism/Protein	Mechanism*	Possible energetic	Reference
Tomato/LeAMT1;1	1	pH gradient independent Δψ dependent	[55]
Tomato/LeAMT1;2	1	pH gradient independent Δψ dependent	[56]
Tomato/LeAMT1;1	1 or 2	Δψ dependent	[57]
Arabidopsis/AtAMT1;1	1	pH gradient independent Δψ dependent	[58]
Tomato/LeAMT1;2	1 or 2	pH gradient independent Δψ dependent	[59]
Arabidopsis/AtAMT1;2	1 or 2	Δψ dependent	[60]
Arabidopsis/AtAMT1;1	1	pH gradient independent Δψ dependent	[61]
Wheat/TaAMT1;1	2	Proton gradients stimulate. Δψ independent	[62]
Lotus/LjAMT2;2	4	Proton gradients stimulate. Δψ independent	[63]
Arabidopsis/AMT2	4	pH gradient independent Δψ independent	[64]
Bean PvAMT1;1	3	Proton gradients stimulate. Δψ dependent	[65]
Arabidopsis/AtAMT1;2	2	Not determined	[66]
Rice/OsAMT1;1	1	pH gradient independent Δψ dependent	[67]
Liverwort/MpAMT1;2	2	pH gradient dependent Δψ dependent	[68]
Arabidopsis/AtAMT1;1, 1;2, 1;3 and 2;1	2 or 4	Not determined	[69]

^*Mechanism: 1- NH₄⁺ uniport, 2- NH₄⁺ deprotonation followed by NH₃/H⁺ conduction, 3- NH₄⁺/H⁺ symport, 4- NH₄⁺ deprotonation followed by the conduction of NH₃ only.