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BioMed Research International
Volume 2014 (2014), Article ID 834134, 10 pages
http://dx.doi.org/10.1155/2014/834134
Research Article

Oxidative Stress and NO Signalling in the Root Apex as an Early Response to Changes in Gravity Conditions

1DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy
2HSO-USB, ESTEC, European Space Agency, Keplerlaan 1, 2200 AG Noordwijk, The Netherlands
3IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany

Received 16 May 2014; Accepted 16 July 2014; Published 17 August 2014

Academic Editor: Monica Monici

Copyright © 2014 Sergio Mugnai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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.