Table 1.
Overview of internal oxygen concentrations within crop seeds
| Species | O2 concentration (µm) | Remarks | Reference |
|---|---|---|---|
| Broad bean* (Vicia faba) | 9 | O2 concentration depends on developmental stage and increases under light | Rolletschek et al. (2002) |
| Pea* (Pisum sativum) | 2 | Minimum O2 at early developmental stages; O2 increases under light | Rolletschek et al. (2003) |
| Soybean* (Glycine max) | 2 | Transient increase in O2 under light is followed by a compensatory rise in respiratory activity | Rolletschek et al. (2005a) |
| Rapeseed* (Brassica napus) | 10 | No data on light/stage dependence | Vigeolas et al. (2003) |
| Barley† (Hordeum vulgare) | 3 | Deep O2 gradients under light conditions; O2 concentration within endosperm decreases at main storage stage and increases slightly under light | Rolletschek et al. (2004) |
| Wheat† (Triticum aestivum) | 25 | Measurements during light phase; no data on developmental changes | VanDongen et al. (2004) |
| Maize‡ (Zea mays) | 4 | O2 concentration depends on developmental stage but no light effects; minimum concentrations in starchy endosperm but higher in embryo | Rolletschek et al. (2005b) |
| Sunflower‡ (Helianthus annuus) | 3 | O2 concentration depends on developmental stage but no light effects | Rolletschek et al. (2007) |
The mean O2 concentration was measured at ambient air under dark conditions (except for wheat) using fibre-optic microsensors.
*
The endogenous oxygen concentration depends strongly on light supply.
†
The green pericarp surrounds the nongreen starchy endosperm, and supplies significant amounts of photosynthetically released oxygen towards the interior.
‡
Nongreen seeds are fully dependent on diffusive oxygen uptake and thus lack any light dependence of their oxygen status.