INSTITUTO DE FISIOLOGIA VEGETAL
Unidad Ejecutora - UE
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Characterization of the antioxidant response in two Populus deltoides clones with different sensitivity to flooding
RODRÍGUEZ MARÍA EMILIA; ACHINELLI, FABIO; BÁRTOLI CARLOS; LUQUEZ VIRGINIA M.C.
Simposio; IPS VI; 2014
Flooding causes anoxia or hypoxia in plants. When the stress episode ends, sudden oxygen exposure of tissues that have lacked oxygen can induce the generation of active oxygen species (AOS), causing oxidative stress damage. To prevent this, plants have systems of enzymatic and non-enzymatic antioxidants. There is no information on the impact of post-anoxic injury in the recovery of Populus plants after flooding, nor whether the degree of susceptibility is related to the antioxidant content. Our aim was to characterize the response of the antioxidant system in poplar during flooding and post-flooding period. Two P. deltoides clones with different response to flooding, Alton (tolerant) and ST67 (sensitive), were grown in pots in a greenhouse. Flooding was imposed by covering the pots with tap water up to 5 cm over the soil surface, for 28 days. Afterwards, pots were removed from the water and left to drain for one day. Leaf and root samples were taken on days 0 and 28 of the flooding period, and 0 and 24 hours after the end of flooding. Ascorbic acid (AsA), glutathione (GSH), peroxidase (PX) and ascorbate peroxidase (APX) were determined. In leaves and roots of flooded Alton plants, no change was observed in AsA, GSH and PX levels, and APX only had a transient increase immediate to reoxygenation. These results could indicate that antioxidants would be removing AOS generated during post-anoxic stress, without its detoxification capacity being exceeded. In leaves of flooded plants of ST67, AsA increased during recovery. In roots, AsA and GSH content were reduced, and APX activity was enhanced, both at the end of flooding and during recovery. The response of this clone suggests that antioxidants would be removing AOS generated both by flooding and post-anoxic stress. The greater antioxidant response of ST67 with respect to Alton, indicate a higher level of stress, which is consistent with its greater growth reduction during an episode of flooding.