Soil carbon dioxide venting through rice roots.

Autor: Kirk GJD; School of Water, Energy and Environment, Cranfield University, Cranfield, UK., Boghi A; School of Water, Energy and Environment, Cranfield University, Cranfield, UK.; Faculty of Engineering and Environment, University of Southampton, Southampton, UK., Affholder MC; School of Water, Energy and Environment, Cranfield University, Cranfield, UK., Keyes SD; Faculty of Engineering and Environment, University of Southampton, Southampton, UK., Heppell J; Faculty of Engineering and Environment, University of Southampton, Southampton, UK., Roose T; Faculty of Engineering and Environment, University of Southampton, Southampton, UK.
Jazyk: angličtina
Zdroj: Plant, cell & environment [Plant Cell Environ] 2019 Dec; Vol. 42 (12), pp. 3197-3207. Date of Electronic Publication: 2019 Aug 19.
DOI: 10.1111/pce.13638
Abstrakt: The growth of rice in submerged soils depends on its ability to form continuous gas channels-aerenchyma-through which oxygen (O 2 ) diffuses from the shoots to aerate the roots. Less well understood is the extent to which aerenchyma permits venting of respiratory carbon dioxide (CO 2 ) in the opposite direction. Large, potentially toxic concentrations of dissolved CO 2 develop in submerged rice soils. We show using X-ray computed tomography and image-based mathematical modelling that CO 2 venting through rice roots is far greater than thought hitherto. We found rates of venting equivalent to a third of the daily CO 2 fixation in photosynthesis. Without this venting through the roots, the concentrations of CO 2 and associated bicarbonate (HCO 3 - ) in root cells would have been well above levels known to be toxic to roots. Removal of CO 2 and hence carbonic acid (H 2 CO 3 ) from the soil was sufficient to increase the pH in the rhizosphere close to the roots by 0.7 units, which is sufficient to solubilize or immobilize various nutrients and toxicants. A sensitivity analysis of the model showed that such changes are expected for a wide range of plant and soil conditions.
(© 2019 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
Externí odkaz: