. 2010 Nov 30;22(11):3621–3633. doi: 10.1105/tpc.110.076216

Table 1.

Ammonium and Nitrate Stimulate Lateral Root Development in a Complementary Manner

N Supply	Microscopy Analysis of First-, Second-, or Third-Order Lateral Roots
	Total Lateral Root Length (cm·Plant⁻¹)
	First-Order	Second-Order	Third-Order
0.8 mM NO₃⁻	10.60 ± 0.45^b	35.83 ± 3.92^b	0.79 ± 0.20^a
0.8 mM NH₄⁺	04.81 ± 0.49^a	08.01 ± 0.75^a	2.88 ± 0.26^b
0.4 mM NH₄NO₃	11.39 ± 0.98^b	41.04 ± 7.71^b	1.42 ± 0.29^a
	Total Number of Lateral Root Primordia Initiated (Plant⁻¹)
	First-Order	Second-Order	Third-Order
0.8 mM NO₃⁻	nd	33.83 ± 2.54^a	24.27 ± 2.31^a
0.8 mM NH₄⁺	nd	25.66 ± 1.65^a	49.08 ± 3.87^b
0.4 mM NH₄NO₃	nd	55.88 ± 4.19^b	71.83 ± 8.41^c
	Density of Lateral Root Primordia Initiated (Number·cm⁻¹)
	First-Order	Second-Order	Third-Order
0.8 mM NO₃⁻	nd	3.33 ± 0.38^a	0.78 ± 0.12^a
0.8 mM NH₄⁺	nd	5.47 ± 0.60^b	6.52 ± 0.54^b
0.4 mM NH₄NO₃	nd	5.14 ± 0.24^b	2.10 ± 0.42^a

Microscopy analysis of first-, second-, or third-order lateral roots length and total number or density of lateral root primordia initiated in Arabidopsis CYCB1:GUS plants grown under local supply of ammonium, nitrate, or ammonium nitrate in vertically split agar plates (for histochemical staining and determination of lateral root measures, see Methods). Values represent means (±se) of 12 to 21 individual plants per treatment, and different letters denote significant differences among nitrogen treatments at P < 0.05 (Tukey’s test); nd, not determined.