Figure 1.

Lateral Root Development Is Differently Affected by Local Nitrate and Ammonium Supply.

(A) to (F) Total lateral root length per unit of primary root in the top ([A] and [B]), middle ([C] and [D]), and bottom ([E] and [F]) root compartment.

(G) to (L) Lateral root density in the top ([G] and [H]), middle ([I] and [J]), and bottom ([K] and [L]) root compartment.

Arabidopsis plants were grown for 15 d on horizontally split agar plates and supplemented with increasing concentrations of nitrogen in the form of KNO₃ ([A], [C], [E], [G], [I], and [K]) or NH₄Cl ([B], [D], [F], [H], [J], and [L]) only in the middle compartment. Bars represent mean values (± se) of 21 individual plants per treatment, and different letters denote significant differences among means at P < 0.05 (Tukey’s test); ns, not significant.