Photosynthetic characteristics and enzymatic antioxidant capacity of leaves from wheat cultivars exposed to drought

• Published in: Biochimica et biophysica acta 2012-08, Vol.1817 (8), p.1516-1523
• Main Author: Huseynova, Irada M.
• Format: Article
• Language: English
• Subjects: antioxidant activity; Antioxidant enzyme; Antioxidants - metabolism; Catalase - metabolism; chlorophyll; Chlorophyll - analysis; Chlorophyll fluorescence; cultivars; Drought; drought tolerance; Droughts; durum wheat; ears; flowering; genotype; Glutathione Reductase - metabolism; irrigation; leaves; milk; Ontogenesis; ontogeny; Photosynthesis; Photosystem II; Plant Leaves - metabolism; superoxide dismutase; Superoxide Dismutase - metabolism; Triticum - metabolism; Triticum aestivum; Triticum turgidum subsp. durum; water content; water stress; Wheat cultivar
• ISSN: 0005-2728; 0006-3002; 1879-2650
• DOI: 10.1016/j.bbabio.2012.02.037

Two durum (Triticum durum L.), Barakatli-95 and Garagylchyg-2; and two bread (Triticum aestivum L.) wheat cultivars, Azamatli-95 and Giymatli-2/17 with different sensitivities to drought were grown in the field on a wide area under normal irrigation and severe water deficit. Drought caused a more pronounced inhibition in photosynthetic parameters in the more sensitive cvs Garagylchyg-2 and Giymatli-2/17 compared with the tolerant cvs Barakatli-95 and Azamatli-95. Upon dehydration, a decline in total chlorophyll and relative water content was evident in all cultivars, especially in later periods of ontogenesis. Potential quantum yield of PS II (Fv/Fm ratio) in cv Azamatli-95 was maximal during stalk emergency stage at the beginning of drought. This parameter increased in cv Garagylchyg-2, while in tolerant cultivar Barakatli-95 significant changes were not observed. Contrary to other wheat genotypes in Giymatli-2/17 drought caused a decrease in PS II quantum yield. Drought-tolerant cultivars showed a significant increase in CAT activity as compared to control plants. In durum wheat cultivars maximal activity of CAT was observed at the milk ripeness and in bread wheat cultivars at the end of flowering. APX activity also increased in drought-treated leaves: in tolerant wheat genotypes maximal activity occurred at the end of flowering, in sensitive ones at the end of ear formation. GR activity increased in the tolerant cultivars under drought stress at all stages of ontogenesis. SOD activity significantly decreased in sensitive cultivars and remained at the control level or increased in resistant ones. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. ► Great decrease in RWC of leaves was observed at wax ripeness stage of ontogenesis. ► All stressed plants have maximum pigment content in the end of earing stage. ► Drought caused a decrease in PSII quantum yield in sensitive cv Giymatli-2/17. ► Drought-tolerant cultivars showed significant increase in CAT, APX and GR activity. ► SOD activity significantly decreased in sensitive cultivars.