Figure 1: Interactive effects of UV-B radiation and nitrogen on NUE (g g−1 N) of maize. Means ± S.E. within each N level followed by the same letter (capital letters for N effects) were not significantly different at . Significance of main effects: ns: not significant, **, ***; UV: high UV-B treatment; C: ambient UV-B treatment; N0, N1, N2, N3: 0, 100, 200 and 300 kg N ha−1.