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Oxidative stress and NO signalling in the root apex as an early response to changes in gravity conditions.

Mugnai S, Pandolfi C, Masi E, Azzarello E, Monetti E, Comparini D, Voigt B, Volkmann D, Mancuso S - Biomed Res Int (2014)

Bottom Line: The same results were obtained by ROS measurement.The detrimental effect of D'orenone, disrupting the polarised auxin transport, on the onset of the oxygen peaks during the microgravity period was also evaluated.Results indicates an active role of NO and ROS as messengers during the gravitropic response, with probable implications in the auxin redistribution.

View Article: PubMed Central - PubMed

Affiliation: DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy ; HSO-USB, ESTEC, European Space Agency, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands.

ABSTRACT
Oxygen influx showed an asymmetry in the transition zone of the root apex when roots were placed horizontally on ground. The influx increased only in the upper side, while no changes were detected in the division and in the elongation zone. Nitric oxide (NO) was also monitored after gravistimulation, revealing a sudden burst only in the transition zone. In order to confirm these results in real microgravity conditions, experiments have been set up by using parabolic flights and drop tower. The production of reactive oxygen species (ROS) was also monitored. Oxygen, NO, and ROS were continuously monitored during normal and hyper- and microgravity conditions in roots of maize seedlings. A distinct signal in oxygen and NO fluxes was clearly detected only in the apex zone during microgravity, with no significant changes in normal and in hypergravity conditions. The same results were obtained by ROS measurement. The detrimental effect of D'orenone, disrupting the polarised auxin transport, on the onset of the oxygen peaks during the microgravity period was also evaluated. Results indicates an active role of NO and ROS as messengers during the gravitropic response, with probable implications in the auxin redistribution.

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Related in: MedlinePlus

Oxygen influx measured on the two sides of a gravistimulated and a vertical root. Upper graph refers to the upper side of a gravistimulated root, whereas the second graph refers to the bottom side of a gravistimulated root.
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fig1: Oxygen influx measured on the two sides of a gravistimulated and a vertical root. Upper graph refers to the upper side of a gravistimulated root, whereas the second graph refers to the bottom side of a gravistimulated root.

Mentions: In normal (vertical) conditions, strong differences between the constituent zones of the maize root (DZ, TZ, and EZ) were clearly evident. The TZ appeared to be the most active zone in the uptake of oxygen from the surrounding solution (Figure 1). The spatial patterns of the oxygen influxes in the entire root apex showed a marked peak in the TZ (110 pmol cm−2 s−1) at 1–1.5 mm from the maize root tip. A minor oxygen influx peak (75 pmol cm−2 s−1) was also evident in the DZ. Importantly, the TZ was the only root apex region significantly affected with regards to gravistimulation; in fact, the marked peak of oxygen influx was greatly enhanced in the upper part of the horizontal (gravistimulated) root, whereas the DZ maintained a similar pattern. On the contrary, the bottom side of the horizontal root showed a normal behaviour. The increase of oxygen influx at TZ level appeared as a very quick response following gravistimulation, as it was clearly evident after less than 30 seconds in the upper side of the root (Figure 2), while the bottom part remained unaffected.


Oxidative stress and NO signalling in the root apex as an early response to changes in gravity conditions.

Mugnai S, Pandolfi C, Masi E, Azzarello E, Monetti E, Comparini D, Voigt B, Volkmann D, Mancuso S - Biomed Res Int (2014)

Oxygen influx measured on the two sides of a gravistimulated and a vertical root. Upper graph refers to the upper side of a gravistimulated root, whereas the second graph refers to the bottom side of a gravistimulated root.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150467&req=5

fig1: Oxygen influx measured on the two sides of a gravistimulated and a vertical root. Upper graph refers to the upper side of a gravistimulated root, whereas the second graph refers to the bottom side of a gravistimulated root.
Mentions: In normal (vertical) conditions, strong differences between the constituent zones of the maize root (DZ, TZ, and EZ) were clearly evident. The TZ appeared to be the most active zone in the uptake of oxygen from the surrounding solution (Figure 1). The spatial patterns of the oxygen influxes in the entire root apex showed a marked peak in the TZ (110 pmol cm−2 s−1) at 1–1.5 mm from the maize root tip. A minor oxygen influx peak (75 pmol cm−2 s−1) was also evident in the DZ. Importantly, the TZ was the only root apex region significantly affected with regards to gravistimulation; in fact, the marked peak of oxygen influx was greatly enhanced in the upper part of the horizontal (gravistimulated) root, whereas the DZ maintained a similar pattern. On the contrary, the bottom side of the horizontal root showed a normal behaviour. The increase of oxygen influx at TZ level appeared as a very quick response following gravistimulation, as it was clearly evident after less than 30 seconds in the upper side of the root (Figure 2), while the bottom part remained unaffected.

Bottom Line: The same results were obtained by ROS measurement.The detrimental effect of D'orenone, disrupting the polarised auxin transport, on the onset of the oxygen peaks during the microgravity period was also evaluated.Results indicates an active role of NO and ROS as messengers during the gravitropic response, with probable implications in the auxin redistribution.

View Article: PubMed Central - PubMed

Affiliation: DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy ; HSO-USB, ESTEC, European Space Agency, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands.

ABSTRACT
Oxygen influx showed an asymmetry in the transition zone of the root apex when roots were placed horizontally on ground. The influx increased only in the upper side, while no changes were detected in the division and in the elongation zone. Nitric oxide (NO) was also monitored after gravistimulation, revealing a sudden burst only in the transition zone. In order to confirm these results in real microgravity conditions, experiments have been set up by using parabolic flights and drop tower. The production of reactive oxygen species (ROS) was also monitored. Oxygen, NO, and ROS were continuously monitored during normal and hyper- and microgravity conditions in roots of maize seedlings. A distinct signal in oxygen and NO fluxes was clearly detected only in the apex zone during microgravity, with no significant changes in normal and in hypergravity conditions. The same results were obtained by ROS measurement. The detrimental effect of D'orenone, disrupting the polarised auxin transport, on the onset of the oxygen peaks during the microgravity period was also evaluated. Results indicates an active role of NO and ROS as messengers during the gravitropic response, with probable implications in the auxin redistribution.

Show MeSH
Related in: MedlinePlus