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| Titel |
Root water uptake and root permeability measured by heavy water injection and neutron radiography |
| VerfasserIn |
Mohsen Zarebanadkouki, Andrea Carminati, Ahmad Moradi, Hans-Jörg Vogel, Abbas Dara, Hanna Esser, Stefan Hartmann, Nikolay Kardjilov |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250052734
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| Zusammenfassung |
| Water uptake by plants is a major component of soil water balance. Physical properties of the
root-soil interface and the hydraulic conductivity of roots are known to be important
parameters controlling the water uptake rate. Despite the importance of these components,
there is only a limited number of studies reporting their direct measurement. The lack of
experimental data is largely due to technical problem of measuring water fluxes across soil
and roots in-situ.
Objective of this study was to develop a method to map locations and temporal -dynamics of
root water uptake of living plants. We combined neutron radiography with the tracer
Deuterium Oxide (D2O). D2O has similar physical and chemical properties to normal water
(H2O) but it has a much lower neutron attenuation coefficient compared to normal water,
which makes it well visible in neutron radiography.
We grew lupins in 30 x 15 x 1 cm containers filled with sandy soil. 16 days after planting, we
locally injected D2O in the soil next to various parts of the root system. We used
time-series neutron radiography to image the D2O redistribution after injection. D2O
injection at same locations during day and night was carried out for separating
diffusion of D2O in H2O and convection processes due to net mass flow. The results
showed that some minutes after D2O injection, neutron attenuation inside the roots
decreased due to D2O entering the roots. The signal was used to estimate the diffusional
permeability of roots as well as the net root water uptake. Afterwards, we observed that
convective D2O flow along the root till the plant shoot. No convective flow of D2O was
visible during the night measurement. We also observed that water uptake rate
varied among roots: lower D2O uptake by the tap root, and higher uptake by lateral
roots. We conclude that neutron radiography combined with D2O injection is a
promising technique to investigate root permeability and water fluxes in soil and plants. |
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