Effect of photooxidative stress induced by paraquat in two wheat cultivars with differential tolerance to water stress

• Published in: Plant science (Limerick) 2003-05, Vol.164 (5), p.841-848
• Main Authors: Lascano, H.Ramiro, Melchiorre, Mariana N., Luna, Celina M., Trippi, Victorio S.
• Format: Article
• Language: English
• Subjects: Active oxygen species; Agronomy. Soil science and plant productions; Ascorbate; Ascorbate peroxidase; Biological and medical sciences; Economic plant physiology; Fundamental and applied biological sciences. Psychology; Glutathione; Glutathione reductase; Plant physiology and development; Superoxide dismutase; Triticum aestivum; Water and solutes. Absorption, translocation and permeability; Water relations, transpiration, stomata
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/S0168-9452(03)00073-6

We previously demonstrated that the differential water stress tolerance of two wheat cvs ( Triticum aestivum L cvs Oasis and Elite) were related with the capacity of each cv. to modulate the antioxidant system response. In order to investigate the possible occurrence of the cross-tolerance phenomenon, we have now analysed the antioxidant system response of these wheat cvs subjected to photooxidative stress induced by different paraquat concentrations combined with relative excess of light. Contrary to our previous idea, the drought-tolerant cv. Elite was more sensitive to paraquat treatment than the drought-sensitive cv. Oasis. Chlorophyll and protein degradation was higher in Elite than in Oasis. This behaviour of oxidative damage parameters was accompanied by different antioxidant system responses of the two cvs. In general, both antioxidant enzyme activities and non-enzymatic antioxidant compounds showed lower levels in Elite than in Oasis. These results are discussed in relation to the oxidative stress induced by paraquat treatment and by water stress.