Table I. Growth, sugar concentration, oxygen consumption rate, and ADH activity of coleoptiles from rice and wheat seedlings exposed to aeration or anoxia.
Rice seeds were germinated and grown under aeration for 4 d (control), anoxia for 6 d (anoxically germinated; 6 d N2), or subsequently switched to 1 d of anoxia (anoxically switched; 4 d air + 1 d N2) or 1 d of air (aerobically switched; 6 d N2 + 1 d air). Wheat seeds were treated with control conditions or were anoxically switched.
| Parameters | Treatments | Rice |
Wheat |
||||
| Coleoptiles | Leaves | Roots | Coleoptiles | Leaves | Roots | ||
| Growth (mm) | 4 d air | 11.9 ± 0.9 | – | – | 28.1 ± 2.7 | – | – |
| 4 d air + 1 d N2 | 14.2 ± 1.0a | – | – | 26.2 ± 1.5 | – | – | |
| 6 d N2 | 7.1 ± 0.7a | – | – | – | – | – | |
| 6 d N2 + 1 d air | 9.7 ± 0.7b | – | – | – | – | – | |
| Sugar concentration (mg hexose g−1 fresh wt) | 4 d air | 44.8 ± 1.4 | 55.8 ± 2.1 | 28.0 ± 2.8 | 37.0 ± 0.7 | 64.9 ± 2.5 | 12.4 ± 1.2 |
| 4 d air + 1 d N2 | 21.6 ± 0.9a | 31.3 ± 0.7a | 13.5 ± 0.7a | 26.4 ± 1.2a | 40.4 ± 1.0a | 3.4 ± 0.3a | |
| 6 d N2 | 3.5 ± 0.2a | – | – | – | – | – | |
| 6 d N2 + 1 d air | 7.7 ± 1.1b | – | – | – | – | – | |
| Oxygen consumption rate (nmol min−1 g−1 fresh wt) | 4 d air | 126.3 ± 5.1 | 302.2 ± 10.8 | 398.8 ± 20.2 | 140.6 ± 6.0 | 478.8 ± 36.2 | 436.8 ± 14.4 |
| 4 d air + 1 d N2 | 104.7 ± 2.8a | 132.7 ± 20.0a | 82.1 ± 1.2a | 146.1 ± 8.9 | 336.7 ± 10.1 | 177.3 ± 1.0a | |
| 6 d N2 | 67.4 ± 6.0a | – | – | – | – | – | |
| 6 d N2 + 1 d air | 134.0 ± 11.8b | – | – | – | – | – | |
| ADH activity (units mg−1 protein) | 4 d air | 0.75 ± 0.06 | 0.94 ± 0.07 | 0.94 ± 0.05 | 0.25 ± 0.01 | 0.09 ± 0.01 | 0.32 ± 0.02 |
| 4 d air + 1 d N2 | 2.68 ± 0.13a | 3.42 ± 0.04a | 5.22 ± 0.70a | 0.59 ± 0.01a | 0.28 ± 0.01a | 1.08 ± 0.01a | |
| 6 d N2 | 6.61 ± 0.48a | – | – | – | – | – | |
| 6 d N2 + 1 d air | 4.38 ± 0.24b | – | – | – | – | – | |
a
The value of continuously anoxic/anoxically switched samples is P < 0.05 when compared with continuously aerated samples.
b
The value of aerobically switched samples is P < 0.05 when compared with continuously anoxic samples.