 |
| Titel |
Neutron radiography and modelling of water flow and D2O transport in soil and plants |
| VerfasserIn |
Mohsen Zare, Andrea Carminati, Eva Kröner |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250093949
|
| Publikation (Nr.) |
 EGU/EGU2014-9182.pdf |
|
|
|
|
|
| Zusammenfassung |
| Our understanding of soil and plant water relations is currently limited by the lack of
experimental methods to measure the water fluxes in soil and plants. Our study aimed to
develop a new non-destructive method to measure the local fluxes of water into
roots of plants growing in soil. We injected deuterated water (D2O) near the roots
of lupines growing in sandy soils, and we used neutron radiography to image the
transport of D2O through the root system. The experiments were performed during
day, when plants were transpiring, and at night, when transpiration was reduced.
The radiographs showed that: 1) the radial transport of D2O from soil and roots
depended similarly from diffusion and convection; and 2) the axial transport of
D2O along the root xylem was largely dominated by convection. To determine the
convective fluxes from the radiographs, we simulated the D2O transport in soils and
roots. A dual porosity model was used to describe the apoplastic and symplastic
pathways of water across the root tissue. Other features as the endodermis and the
xylem were also included in the model. The D2O transport was modelled solving a
convection-diffusion numerical model in soil and plants. The diffusion coefficients of the root
tissues were inversely estimated by simulating the experiments at night under the
assumption that at night the convective fluxes were negligible. Inverse modelling of
the experiment at day gave the profile of water fluxes into the roots, as well as the
ration between the apoplastic and symplastic flow. For 24 day-old lupine grown in
a sandy soil with uniform water content, our modelling results showed that root
water uptake was higher at the proximal parts of the roots near soil surface and it
decreased toward the distal parts. The results indicated the water crossed the root cortex
mainly through the apoplastic pathway. The method allows the quantification of the
root properties and the regions of root water uptake along root systems growing in
soils. |
|
|
|
|
|
|