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| Titel |
Measurements of water uptake of maize roots: insights for traits that influence water transport from the soil |
| VerfasserIn |
Mutez A. Ahmed, Mohsen Zarebanadkouki, Eva Kroener, Andrea Carminati |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105278
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| Publikation (Nr.) |
 EGU/EGU2015-4766.pdf |
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| Zusammenfassung |
| Water availability is a primary constraint to the global crop production. Although
maize (Zea mays L.) is one of the most important crops worldwide, there is limited
information on the function of different root segments and types in extracting water from
soils. Aim of this study was to investigate the location of water uptake in maize
roots.
We used neutron radiography to: 1) image the spatial distribution of maize roots in soil
and 2) trace the transport of injected deuterated water (D2O) in soil and roots. Maize plants
were grown in aluminum containers (40x38x1 cm) filled with sandy soil. The soil was
partitioned into different compartments using 1-cm-thick layers of coarse sand. When the
plants were two weeks-old we injected D2O into selected soil compartments. The
experiments were performed during the day (transpiring plants) and night (non transpiring
plants). The transport of D2O into roots was simulated using a convection–diffusion
numerical model of D2O transport into roots. By fitting the observed D2O transport
we quantified the diffusion coefficient and the water uptake of the different root
segments.
The maize root architecture consisted of a primary root, 4-5 seminal roots and many
lateral roots connected to the primary and seminal roots. Laterals emerged from the proximal
15 cm of the primary and seminal roots. Both during day and night measurements,
D2O entered more quickly into lateral roots than into primary and seminal roots.
The quick transport of D2O into laterals was caused by the small radius of lateral
roots. The diffusion coefficient of lateral roots (4.68x10-7cm2s-1)was similar
to that of the distal segments of seminal roots (4.72x10-7cm2s-1) and higher
than of the proximal segments (1.42x10-7cm2s-1). Water uptake of lateral roots
(1.64x10-5cms-1)was much higher than that of the distal segments of seminal
roots (1.18x10-12cms-1). Water uptake of the proximal seminal segments was
negligible.
We conclude that the function of lateral roots is to absorb water from the soil, while the
function of the primary and seminal roots is to axially transport water to the shoot. Breeding
for lateral roots with high radial conductivity and seminal roots with large xylem vessels
diameter would be beneficial in agroecosystems where water is available. In contrast,
in arid and semi-arid areas seminal roots with a smaller xylem vessel diameter
combined with deep branching of laterals would reduce transpiration rate and at the
same time allow the uptake of water stored in the subsoil (Richards and Passioura
1989).
Reference
Richards RA, Passioura JB. (1989) A breeding program to reduce the diameter of the
major xylem vessel in the seminal roots of wheat and its effect on grain yield in
rain-fed environments. Australian Journal of Agricultural Research 40, 943–950. |
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