Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/2/2003
Publication Date: 11/6/2003
Citation: Mahan, J.R., Wanjura, D.F. 2003. Season variation in antioxidant metabolism in cotton under field water stress[abstract]. ASA-CSSA-SSSA Proceedings.
Technical Abstract: The exposure of plants to water deficits can result in the production of reactive oxygen species (ROS) that diminish plant performance. This study determines the variability in antioxidants in cotton under water stress in the field. Irrigation treatments resulted in relatively severe water stresses in both years of the study. In year 1 glutathione content varied 2-fold and the reduced form was predominant. The glutathione content in year 2 was relatively constant in all three water treatments. The ratio of reduced/oxidized glutathione did not vary with stress with the exception of an increase in the oxidized form at mid-season in the dryland treatment. The deficit irrigation treatment did not respond to water deficit. Glutathione reductase activity increased more than 2-fold from early to late season and there was no water effect. Ascorbate varied 4-fold seasonally with no effect of water. Ascorbate peroxidase rose more than 3-fold from early to late season. No differences were associated with the water. Malondialdehyde rose almost 2-fold in season with no effect of water deficit. The absence of elevated malondialdehyde due to water deficits coupled with the failure to detect stress related variation in antioxidants suggest that it was sufficient in all water levels. The variation in antioxidant metabolism over time but not in response to water deficits suggests that improvement of plant performance through the modification of antioxidant metabolism may be of limited value.