Table 1.
Mean values ± SD (n = 3) of photosynthetic parameters derived from the photosynthetic photon flux density (PPFD) response curves in maize plants grown under low (LD), normal (ND), and high density (HD) planting at 0, 10, 20, 30, and 40 d after anthesis. Different lowercase letters (a, b, c) denote statistical differences by LSD test (p ≤ 0.05) between different treatments.
| Days After Anthesis (d) |
Plant Density (Plants hm−2) |
Amax (μmol m−2 s−1) |
Rd (μmol m−2 s−1) |
AQE | LCP (μmol m−2 s−1) |
LSP (μmol m−2 s−1) |
|---|---|---|---|---|---|---|
| 0 | LD | 44.3 a | 6.4 a | 0.052 a | 123.1 b | 975.48 c |
| ND | 39.6 b | 5.9 b | 0.043 b | 137.9 a | 1058.70 a | |
| HD | 38.0 c | 4.9 c | 0.042 b | 117.3 c | 1021.17 b | |
| 10 | LD | 38.2 a | 5.0 a | 0.043 b | 117.1 a | 1005.0 a |
| ND | 36.6 b | 4.2 b | 0.047 a | 89.0 b | 867.9 b | |
| HD | 35.6 c | 3.4 c | 0.045 b | 74.9 c | 866.7 b | |
| 20 | LD | 31.6 a | 4.4 a | 0.035 b | 126.7 a | 1029.0 a |
| ND | 32.8 a | 3.8 b | 0.040 a | 93.9 b | 914.6 b | |
| HD | 30.1 b | 3.2 c | 0.042 a | 75.5 c | 792.3 c | |
| 30 | LD | 24.0 c | 4.0 a | 0.030 c | 132.5 a | 933.8 b |
| ND | 32.0 a | 3.5 b | 0.037 b | 94.9 b | 961.4 a | |
| HD | 27.5 b | 2.8 c | 0.040 a | 70.4 c | 757.7 c | |
| 40 | LD | 19.8 c | 2.7 a | 0.024 c | 112.9 a | 939.1 a |
| ND | 23.0 b | 2.6 a | 0.031 b | 84.2 b | 824.7 b | |
| HD | 24.2 a | 1.7 b | 0.035 a | 47.7 c | 740.1 c |
Amax, maximum gross photosynthetic rate; Rd, rate of dark respiration; AQE, apparent quantum efficiency; LCP, light compensation point; LSP, light saturation point.