Table 6.
Leaf traits and photosynthetic rate of maize in different treatments. NC: leaf nitrogen concentration (mg N g−1 leaf); gs: stomatal conductance for CO2 (mol m−2 s−1); gw: stomatal conductance for water (mol m−2 s−1); A: photosynthetic rate (μmol CO2 m−2 s−1). No shared letters denote a statistically significant difference (P = 0.05) using Tukey’s HSD. *Means the effect of Block or Week is significant, NS means the effects are not significant. t-tests were used to test the difference between border rows and inner row of 6:3WM treatments, for each week and for the average across the 3 weeks; differences were not significant.
Week | Treatment | SLA (m2 leaf g−1 leaf) | NC (mg N g−1 leaf) | SLN (g N m−2 leaf) | SPAD | g s (mol m−2 s−1) | g w (mol m−2 s−1) | A (μmol CO2 m−2 s−1) |
---|---|---|---|---|---|---|---|---|
29 | SM | 0.023 a | 16.3 a | 0.72 a | 59.4 a | 0.19 a | 0.31 a | 26.7 b |
0:2 WM | 0.022 a | 16.6 a | 0.75 a | 60.3 a | 0.17 a | 0.27 a | 26.7 b | |
6:2 WM | 0.023 a | 15.4 ab | 0.66 ab | 50.1 b | 0.28 a | 0.44 a | 33.5 a | |
6:3 WM | 0.024 a | 12.7 bc | 0.53 bc | 47.8 b | 0.21 a | 0.34 a | 31.1 a | |
8:2 WM | 0.023 a | 11.8 c | 0.52 c | 47.0 b | 0.24 a | 0.38 a | 32.9 a | |
Block | NS | NS | NS | NS | * | * | NS | |
30 | SM | 0.024 bc | 16.4 a | 0.68 a | 59.4 a | 0.11 a | 0.17 a | 18.8 c |
0:2 WM | 0.023 c | 17.0 a | 0.74 a | 60.9 a | 0.17 a | 0.27 a | 22.5 bc | |
6:2 WM | 0.025 ab | 15.4 ab | 0.61 ab | 50.3 b | 0.21 a | 0.33 a | 32.6 a | |
6:3 WM | 0.027 a | 12.1 b | 0.45 c | 47.0 b | 0.14 a | 0.23 a | 24.5 bc | |
8:2 WM | 0.026 ab | 12.1 b | 0.47 bc | 46.1 b | 0.16 a | 0.26 a | 29.0 ab | |
Block | * | NS | NS | NS | NS | NS | NS | |
31 | SM | 0.023 ab | 13.8 ab | 0.59 b | 60.3 a | 0.16 a | 0.26 a | 29.0 ab |
0:2 WM | 0.021 c | 15.0 a | 0.72 a | 62.9 a | 0.14 a | 0.23 a | 26.7 b | |
6:2 WM | 0.022 bc | 13.5 abc | 0.61 ab | 53.0 b | 0.19 a | 0.30 a | 32.2 a | |
6:3 WM | 0.024 a | 11.8 bc | 0.49 b | 48.0 b | 0.16 a | 0.26 a | 30.0 ab | |
8:2 WM | 0.023 abc | 11.5 c | 0.50 b | 47.5 b | 0.18 ab | 0.29 a | 30.6 ab | |
Block | NS | NS | NS | NS | NS | * | NS | |
Mean | SM | 0.024 b | 15.5 a | 0.66 b | 59.7 a | 0.16 b | 0.25 b | 24.8 c |
0:2 WM | 0.022 c | 16.2 a | 0.74 a | 61.3 a | 0.16 b | 0.26 b | 25.3 c | |
6:2 WM | 0.024 b | 14.8 a | 0.63 b | 51.1 b | 0.23 a | 0.36 a | 32.8 a | |
6:3 WM | 0.025 a | 12.2 b | 0.49 c | 47.6 c | 0.18 ab | 0.28 ab | 28.6 b | |
8:2 WM | 0.024 ab | 11.8 b | 0.50 c | 46.9 c | 0.19 ab | 0.31 ab | 30.8 ab | |
Week | * | * | * | NS | * | * | * | |
Block | NS | * | * | * | NS | * | NS |