Table 4.
Interactive effects of UV-B radiation and nitrogen on K concentration (mg g−1) and K 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 | 21.6 | 18.0 | 3.4 | 5.5 | 23.2 | 12.6 a | 6.8 | 3.8 a | 8.1 | 4.5 |
| C | 24.0 | 20.0 | 4.0 | 6.5 | 22.7 | 14.7 a | 6.4 | 4.4 a | 9.2 | 5.4 | |
| Mean | 22.8 | 19.0 | 3.7 B | 6.0 C | 22.9 | 13.6 A | 6.6 | 4.1 C | 8.6 B | 5.0 C | |
|
| |||||||||||
| N1 | UV | 26.7 | 30.4 | 3.9 | 10.1 | 20.5 | 10.5 a | 6.7 | 4.0 a | 7.2 | 6.1 |
| C | 18.9 | 14.4 | 3.9 | 7.6 | 18.7 | 9.1 a | 6.5 | 4.5 a | 8.7 | 8.2 | |
| Mean | 22.8 | 22.4 | 3.9 B | 8.9 BC | 19.6 | 9.8 B | 6.6 | 4.3 C | 8.0 B | 7.1 B | |
|
| |||||||||||
| N2 | UV | 22.4 | 28.0 | 3.7 | 10.7 | 18.4 | 8.2 b | 6.0 | 4.0 b | 6.1 | 6.2 |
| C | 21.8 | 19.2 | 5.1 | 12.2 | 20.4 | 11.7 a | 6.7 | 6.1 a | 12.8 | 10.0 | |
| Mean | 22.1 | 23.6 | 4.4 AB | 11.4 AB | 19.4 | 10.0 B | 6.3 | 5.1 B | 9.4 AB | 8.1AB | |
|
| |||||||||||
| N3 | UV | 23.7 | 27.7 | 4.7 | 12.9 | 19.6 | 13.3 a | 6.1 | 4.6 b | 12.2 | 6.9 |
| C | 22.4 | 20.5 | 6.2 | 13.1 | 21.6 | 10.4 a | 6.0 | 7.1 a | 12.5 | 10.1 | |
| Mean | 23.1 | 24.1 | 5.4 A | 13.0 A | 20.6 | 11.9 AB | 6.1 | 5.8 A | 12.4 A | 8.5 A | |
|
| |||||||||||
| Mean | UV | 23.9 | 26.6 a | 4.0 b | 10.2 | 20.4 | 11.3 a | 6.4 | 4.1 b | 8.7 b | 6.0 b |
| C | 21.8 | 18.5 b | 4.8 a | 9.9 | 20.8 | 11.5 a | 6.4 | 5.5 a | 10.8 a | 8.5 a | |
|
| |||||||||||
| ANOVA | |||||||||||
|
| |||||||||||
| Radiation (R) | ns | * | + | ns | ns | ns | ns | *** | + | *** | |
| Nitrogen (N) | 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.