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O2 dynamics in the rhizosphere of young rice plants (Oryza sativa L.) as studied by planar optodes.

Larsen M, Santner J, Oburger E, Wenzel WW, Glud RN - Plant Soil (2015)

Bottom Line: At onset of darkness, oxia in the rhizosphere was drastically reduced, but subsequently oxia gradually increased, presumably as root and/or soil respiration declined.The study demonstrates a high spatio-temporal heterogeneity in rhizosphere O2 dynamics and difference in ROL between different parts of the rhizosphere.The work documents that spatio-temporal measurements are important to fully understand and account for the highly variable O2 dynamics and associated biogeochemical processes and pathways in the rice rhizosphere.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biology and Nordic Center for Earth Evolution (NordCEE), University of Southern Denmark, 5320 Odense M, Denmark ; Scottish Marine Institute, Scottish Association for Marine Science, Oban, Scotland PA37 1QA UK ; Greenland Climate Research Centre (CO Greenland Institute of National resources), Kivioq 2, Box 570, 3900 Nuuk, Greenland.

ABSTRACT

Background and aims: Radial O2 loss (ROL) strongly affect the O2 availability in the rhizosphere of rice. The ROL create an oxic zone around the roots, protecting the plant from toxic reduced chemical species and regulates the redox chemistry in the soil. This study investigates the spatio-temporal variability in O2 dynamics in the rice rhizosphere.

Method: Applying high-resolution planar optode imaging, we investigated the O2 dynamics of plants grown in water saturated soil, as a function of ambient O2 level, irradiance and plant development, for submerged and emerged plants.

Results: O2 leakage was heterogeneously distributed with zones of intense leakage around roots tips and young developing roots. While the majority of roots exhibited high ROL others remained surrounded by anoxic soil. ROL was affected by ambient O2 levels around the plant, as well as irradiance, indicating a direct influence of photosynthetic activity on ROL. At onset of darkness, oxia in the rhizosphere was drastically reduced, but subsequently oxia gradually increased, presumably as root and/or soil respiration declined.

Conclusion: The study demonstrates a high spatio-temporal heterogeneity in rhizosphere O2 dynamics and difference in ROL between different parts of the rhizosphere. The work documents that spatio-temporal measurements are important to fully understand and account for the highly variable O2 dynamics and associated biogeochemical processes and pathways in the rice rhizosphere.

No MeSH data available.


Related in: MedlinePlus

High resolution two-dimensional visualization of metal plaque on rice roots growing in submerged soil – the metal plaque image is projected onto a black and white image of the root position. A high spatial variability of the plaque among the individual roots can be observed. Imaging can be performed continuously in real time and allows for studies of spatial and temporal developments of plaque. Areas with high densities of plaque are shown with bright colors A.U. (Arbitrary units)
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Fig6: High resolution two-dimensional visualization of metal plaque on rice roots growing in submerged soil – the metal plaque image is projected onto a black and white image of the root position. A high spatial variability of the plaque among the individual roots can be observed. Imaging can be performed continuously in real time and allows for studies of spatial and temporal developments of plaque. Areas with high densities of plaque are shown with bright colors A.U. (Arbitrary units)

Mentions: The distribution of metal plaques was highly patchy and variable between different roots – no roots were observed to have plaque formation along the entire root (Fig. 6). The total visual metal plaque-containing area in the rhizosphere was found to be 739 mm2, 5.9 % of the visible area. Plaque density was highest in a zone 41.1–66.1 mm below the soil surface. Below this zone, plaque density decreased gradually. The soil area covered by plaque did on average corresponded to ~30.4 % of the visible root surface area.Fig. 6


O2 dynamics in the rhizosphere of young rice plants (Oryza sativa L.) as studied by planar optodes.

Larsen M, Santner J, Oburger E, Wenzel WW, Glud RN - Plant Soil (2015)

High resolution two-dimensional visualization of metal plaque on rice roots growing in submerged soil – the metal plaque image is projected onto a black and white image of the root position. A high spatial variability of the plaque among the individual roots can be observed. Imaging can be performed continuously in real time and allows for studies of spatial and temporal developments of plaque. Areas with high densities of plaque are shown with bright colors A.U. (Arbitrary units)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4495287&req=5

Fig6: High resolution two-dimensional visualization of metal plaque on rice roots growing in submerged soil – the metal plaque image is projected onto a black and white image of the root position. A high spatial variability of the plaque among the individual roots can be observed. Imaging can be performed continuously in real time and allows for studies of spatial and temporal developments of plaque. Areas with high densities of plaque are shown with bright colors A.U. (Arbitrary units)
Mentions: The distribution of metal plaques was highly patchy and variable between different roots – no roots were observed to have plaque formation along the entire root (Fig. 6). The total visual metal plaque-containing area in the rhizosphere was found to be 739 mm2, 5.9 % of the visible area. Plaque density was highest in a zone 41.1–66.1 mm below the soil surface. Below this zone, plaque density decreased gradually. The soil area covered by plaque did on average corresponded to ~30.4 % of the visible root surface area.Fig. 6

Bottom Line: At onset of darkness, oxia in the rhizosphere was drastically reduced, but subsequently oxia gradually increased, presumably as root and/or soil respiration declined.The study demonstrates a high spatio-temporal heterogeneity in rhizosphere O2 dynamics and difference in ROL between different parts of the rhizosphere.The work documents that spatio-temporal measurements are important to fully understand and account for the highly variable O2 dynamics and associated biogeochemical processes and pathways in the rice rhizosphere.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biology and Nordic Center for Earth Evolution (NordCEE), University of Southern Denmark, 5320 Odense M, Denmark ; Scottish Marine Institute, Scottish Association for Marine Science, Oban, Scotland PA37 1QA UK ; Greenland Climate Research Centre (CO Greenland Institute of National resources), Kivioq 2, Box 570, 3900 Nuuk, Greenland.

ABSTRACT

Background and aims: Radial O2 loss (ROL) strongly affect the O2 availability in the rhizosphere of rice. The ROL create an oxic zone around the roots, protecting the plant from toxic reduced chemical species and regulates the redox chemistry in the soil. This study investigates the spatio-temporal variability in O2 dynamics in the rice rhizosphere.

Method: Applying high-resolution planar optode imaging, we investigated the O2 dynamics of plants grown in water saturated soil, as a function of ambient O2 level, irradiance and plant development, for submerged and emerged plants.

Results: O2 leakage was heterogeneously distributed with zones of intense leakage around roots tips and young developing roots. While the majority of roots exhibited high ROL others remained surrounded by anoxic soil. ROL was affected by ambient O2 levels around the plant, as well as irradiance, indicating a direct influence of photosynthetic activity on ROL. At onset of darkness, oxia in the rhizosphere was drastically reduced, but subsequently oxia gradually increased, presumably as root and/or soil respiration declined.

Conclusion: The study demonstrates a high spatio-temporal heterogeneity in rhizosphere O2 dynamics and difference in ROL between different parts of the rhizosphere. The work documents that spatio-temporal measurements are important to fully understand and account for the highly variable O2 dynamics and associated biogeochemical processes and pathways in the rice rhizosphere.

No MeSH data available.


Related in: MedlinePlus