Table 3.

Interactive effects of UV-B radiation and nitrogen on P concentration (mg g⁻¹) and P acquired (g m⁻²) by above-ground organs of maize.

Nitrogen	Radiation	Silking				Maturity
		Lc	Sc	La	Sa	Lc	Sc	Gc	La	Sa	Ga
N0	UV	3.19	2.87	0.48	0.83	2.56	0.99 b	3.27	0.42	0.62	2.19 a
	C	3.23	2.73	0.54	0.88	2.72	1.87 a	3.05	0.53	1.18	2.60 a
	Mean	3.21	2.80	0.51 C	0.85 C	2.64	1.43 A	3.16	0.48 C	0.90	2.39 D
N1	UV	3.49	2.77	0.51	0.95	2.52	0.86 b	3.20	0.50	0.58	2.92 b
	C	3.33	2.82	0.69	1.50	2.80	1.19 a	3.39	0.68	1.13	4.24 a
	Mean	3.41	2.80	0.60 BC	1.22 B	2.66	1.02 B	3.30	0.59 BC	0.85	3.58 C
N2	UV	3.38	3.05	0.55	1.18	2.27	1.00 a	3.07	0.50	0.77	3.12 b
	C	3.39	2.85	0.80	1.81	2.93	1.22 a	3.59	0.87	1.31	5.36 a
	Mean	3.38	2.95	0.68 AB	1.49 A	2.60	1.11 B	3.33	0.68 B	1.04	4.24 B
N3	UV	3.38	2.90	0.67	1.33	2.52	0.95 a	3.06	0.59	0.84	3.42 b
	C	3.22	2.46	0.89	1.56	3.15	1.02 a	3.61	1.05	1.22	6.05 a
	Mean	3.30	2.68	0.78 A	1.44 A	2.84	0.99 B	3.33	0.82 A	1.03	4.73 A
Mean	UV	3.37	2.88	0.56 b	1.09 b	2.48 b	0.94 b	3.15 b	0.51 b	0.70 b	2.97 b
	C	3.29	2.71	0.73 a	1.44 a	2.90 a	1.33 a	3.41 a	0.78 a	1.21 a	4.57 a
					ANOVA
Radiation (R)		ns	ns	***	***	*	**	+	***	***	***
Nitrogen (N)		ns	ns	***	***	ns	+	ns	**	ns	***
R × N		ns	ns	ns	ns	ns	+	ns	ns	ns	***

Lc: leaf concentration; Sc: stem concentration; La: amount on leaves; Sa: amount on stems; Gc: grain concentration; Ga: amount on grains; UV: high UV-B treatment; C: ambient UV-B treatment; N0, N1, N2, N3: 0, 100, 200, and 300 kg N ha⁻¹.

Means within each N level followed by the same letter (capital letters for N effects within each column) were not significantly different at P < 0.10. Significance of main effects: ns: not significant; ⁺ P < 0.1; *P < 0.05; **P < 0.01; ***P < 0.001.