Abstract
Plants of white lupin (Lupmus albus L cv Multolupa) and soyabean (Glycine max L cv Clarke) were grown in controlled-environment cabinets, subjected to various stresses and their nodular mtrogenase activity and total root respiration measured When these measurements were used to calculate nodular oxygen diffusion resistance, using a simplified equation for Fields first law of diffusion, it was found that the apparent resistance of stressed nodules increased anomalously with decreases in external oxygen concentration A new analysis procedure is proposed to alleviate this anomaly This procedure also uses the simplified Fick’s law equation but includes a respiratory contribution to the total oxygen flux across the diffusion barrier which is not coupled to mtrogenase activity Also, resistance is modelled as an exponential function of external oxygen concentration Use of this analysis procedure produces realistic values for total resistance and provides a characterisation of this resistance into a minimum value and an adjustment factor for changes in external oxygen It is postulated that the additional respiration component represents the activity of nodule cortex cells involved in the diffusion barrier, particularly that of vascular bundles.
| Original language | English |
|---|---|
| Pages (from-to) | 283-289 |
| Number of pages | 7 |
| Journal | Annals of Botany |
| Volume | 70 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Sept 1992 |
| Externally published | Yes |
Keywords
- Nitrogen fixation
- Nodule
- Oxygen diffusion resistance
- Respiration