A new procedure for the calculation of oxygen diffusion resistance in legume nodules from flow-through gas analysis data
Plants of white lupin (Lupinus albus L cv Multolupa) and soyabean (Glycine max L cv Clarke) were grown in controlled-environment cabinets, subjected to various stresses and their nodular nitrogenase activity and total root respiration measured When these measurements were used to calculate nodular oxygen diffusion resistance, using a simplified equation for Fick's 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 nitrogenase 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 © 1992 Annals of Botany Company.
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | artículo biblioteca |
| Published: |
Oxford University Press
1992-09-01
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| Subjects: | Oxygen diffusion resistance, Nodule, Nitrogen fixation, Respiration, |
| Online Access: | http://hdl.handle.net/10261/199002 http://dx.doi.org/10.13039/100004415 http://dx.doi.org/10.13039/501100003339 http://dx.doi.org/10.13039/100007346 |
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| Summary: | Plants of white lupin (Lupinus albus L cv Multolupa) and soyabean (Glycine max L cv Clarke) were grown in controlled-environment cabinets, subjected to various stresses and their nodular nitrogenase activity and total root respiration measured When these measurements were used to calculate nodular oxygen diffusion resistance, using a simplified equation for Fick's 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 nitrogenase 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 © 1992 Annals of Botany Company. |
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