Table 2.
Seasonal change in dry-mass based leaf N content (Nmass, mg g-1) and resorption efficiency (%) in leaves of fullmoon maple seedlings grown under different light conditions.
| Date | Open | Shade | ||||
|---|---|---|---|---|---|---|
| H0 | L0 | LH1 | LH2 | LH3 | F-statistics | |
| Aug 2 | 26.1 ± 0.6 b | 30.6 ± 0.9 a | ― | ― | ― | 17.0** (F1,6) |
| Aug 20 | 26.8 ± 0.4 b | 29.9 ± 1.2 a | ― | ― | ― | 6.01* (F1,6) |
| Sep 8 | 25.5 ± 0.8 b | 32.1 ± 1.4 a | ― | ― | ― | 17.0** (F1,6) |
| Sep 29 | 20.9 ± 0.4 b | 30.8 ± 1.1 a | ― | ― | ― | 76.0*** (F1,6) |
| Oct 6 | 19.7 ± 0.8 b | 30.5 ± 1.3 a | 27.7 ± 0.7 a | ― | ― | 32.5*** (F2,8) |
| Oct 13 | 17.6 ± 1.7 b | 27.2 ± 1.9 a | 24.2 ± 0.3 ab | 26.7 ± 0.5 a | ― | 6.69** (F3,11) |
| Oct 19 | 18.7 ± 2.1 | 23.2 ± 2.3 | 20.6 ± 1.0 | 21.6 ± 0.6 | 19.5 ± 1.7 | 0.97ns (F4,17) |
| Oct 25 | 12.6 ± 2.3 ab | 16.0 ± 0.9 a | 10.7 ± 0.4 b | 15.3 ± 1.2 ab | 11.1 ± 0.8 b | 4.58ns (F4,15) |
| Shed leaves | 10.0 ± 1.0 b | 11.1 ± 0.4 b | 12.0 ± 0.6 b | 14.6 ± 0.6 a | 10.1 ± 0.2 b | 12.0*** (F4,70) |
| Resorption efficiency (%) | 57.5 ± 8.4a | 64.0 ± 1.3a | 65.9 ± 1.9 a | 52.8 ± 1.9 b | 67.1 ± 0.8 a | 9.48*** (F4,70) |
H0: open condition, L0: shade condition (relative irradiance of ≈ 13% of open condition) throughout the experimental period, LH1: transfer from shade to open on Oct 5, LH2: transfer from shade to open on Oct 12, and LH3: transfer from shade to open on Oct 18. Values are means ± se; n= 3 to 6 for attached leaves, sampled from Aug 2 to Oct 25, and n = 9 to 22 for shed leaves collected from Oct 25 to Nov 1. * denotes significant effect at P ≤ 0.05, ** P ≤ 0.01, and *** P ≤ 0.001. ns indicates no significant effect. Different letters indicate significant differences among means of the light treatments on the same date at P < 0.05.