Table 1.
Growth and morphology of grafted watermelon seedlings exposed for 12 days to either darkness (D) or different light quality regimes [blue (B), white (W), red and blue (RB), as well as red (R); see spectrum in Supplementary Figure S3]. Photosynthetic photon flux density was 20 ± 1 µmol m−2 s−1 during the first 2 days, and 50 ± 1 µmol m−2 s−1 during the following days. Nine plants per treatment were assessed. Means within a column followed by the same letters are not significantly different at p ≤ 0.05 according to Duncan’s multiple range test.
| Light Regime | Survival Ratio (%) | Rootstock Length (cm) | Scion Length (cm) | Scion Stem Diameter (cm) | Leaf Number (plant−1) | Leaf Area (cm2 leaf−1) | Leaf Area (cm2 plant−1) | Plant Dry Weight (g) | Shoot Dry Weight (g) | Specific Leaf Area (SLA; cm2 g−1) | Leaf Mass Ratio (LMR; g g−1) | Root Length (cm) | Root Dry Weight (g) | Shoot to Root Ratio (g/g) | Dickson’s Quality Index (DQI) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| D | 26.3 b | 7.51 | 2.45 b | 0.31 | 2.3 c | 5.01 d | 26.4 d | 0.174 b | 0.165 b | 247 c | 0.38 a,b | 4.14 b | 0.009 c | 19.17 a | 0.006 b |
| B | 100 a | 5.87 | 4.15 a | 0.33 | 5.0 b | 8.24 b | 65.9 b | 0.290 a | 0.265 a | 417 b | 0.35 c | 6.38 a | 0.025 a | 10.53 b | 0.015 a |
| W | 100 a | 6.05 | 4.10 a | 0.38 | 5.0 b | 10.11 a | 80.8 a | 0.251 a | 0.230 a | 540 a | 0.37 b | 6.33 a | 0.021 a | 11.02 b | 0.013 a |
| RB | 100 a | 6.27 | 2.42 b | 0.40 | 6.0 a | 8.15 b | 73.4 a,b | 0.282 a | 0.270 a | 411 b | 0.39 a | 4.24 b | 0.012 b | 23.17 a | 0.013 a |
| R | 100 a | 6.38 | 2.25 b | 0.38 | 5.3 b | 6.28 c | 52.2 c | 0.265 a | 0.256 a | 376 b | 0.34 c | 6.72 a | 0.024 a | 10.16 b | 0.016 a |
| p | <0.0001 | 0.0963 | 0.0075 | 0.23 | <0.0001 | <0.0001 | <0.0001 | 0.0003 | <0.0001 | <0.0001 | <0.0001 | 0.0065 | <0.0001 | <0.0001 | 0.0009 |