title: Oxidative stress and NO signalling in the root apex as an early response to changes in gravity conditions.
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.
authors.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.
authors.forename: Sergio
authors.initials: S
authors.lastname: Mugnai
authors.affiliation: DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy.
authors.forename: Camilla
authors.identifier: 0000-0002-8686-8761
authors.initials: C
authors.lastname: Pandolfi
authors.affiliation: DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy.
authors.forename: Elisa
authors.identifier: 0000-0001-6702-438X
authors.initials: E
authors.lastname: Masi
authors.affiliation: DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy.
authors.forename: Elisa
authors.identifier: 0000-0003-4812-5796
authors.initials: E
authors.lastname: Azzarello
authors.affiliation: DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Monetti
authors.affiliation: DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy.
authors.forename: Diego
authors.identifier: 0000-0002-1546-935X
authors.initials: D
authors.lastname: Comparini
authors.affiliation: IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Voigt
authors.affiliation: IZMB, University of Bonn, Kirschallee 1, 53115 Bonn, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Volkmann
authors.affiliation: DISPAA, University of Florence, Viale delle Idee 30, 50019 Sesto Fiorentino, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Mancuso
mesh_terms: D000704:Analysis of Variance; D019069:Cell Respiration / Q000187:drug effects; D006112:Gravitation; D006861:Hydrogen Peroxide / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D010092:Oximetry; D010100:Oxygen / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014893:Weightlessness; D003313:Zea mays / Q000187:drug effects / Q000378:metabolism*
chemical_list: D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D010100:Oxygen