Verte and Romaine lettuce varieties (Lactuca sativa) show differential responses to high NaCl concentrations

Authors

  • Hela Mahmoudi,

    1. Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar, Tunisia
    2. Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, Canada S7N 0X2
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    • Hela Mahmoudi and Olfa Baatour have participated equally in the elaboration of this work.

  • Olfa Baâtour,

    1. Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar, Tunisia
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  • Jun Huang,

    1. Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, Canada S7N 0X2
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  • Nawel Nasri,

    1. Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar, Tunisia
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  • Imen Ben Salah,

    1. Laboratoired'Adaptation des Plantes aux Stress Abiotiques, CBBC, BP901, 2050 Hammam-Lif, Tunisia
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  • Imen Tarchoun,

    1. Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar, Tunisia
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  • Maha Zaghdoudi,

    1. Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar, Tunisia
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  • Margaret Y. Gruber,

    1. Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, Canada S7N 0X2
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  • Mokhtar Lachaâl,

    1. Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar, Tunisia
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  • Zeineb Ouerghi,

    1. Physiologie et Biochimie de la Tolérance au Sel des Plantes, Faculté des Sciences de Tunis, Campus Universitaire, 2092 Tunis El Manar, Tunisia
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  • Abdelali Hannoufa

    Corresponding author
    1. Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, 1391 Sandford Street, London, ON, Canada N 5V 4T3
    • Agriculture and Agri-Food Canada, Southern Crop Protection and Food Research Centre, 1391 Sandford Street, London, ON, Canada N 5V 4T3
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Abstract

In this study, we report on the relationship between individual antioxidant carotenoids, phenolic fractions, and flavonoids and attenuating NaCl toxicity in two contrasting varieties of lettuce (Lactuca sativa L., var. Verte and Romaine), as a means of developing more precise targets for lettuce breeding. In seedling leaves, carotenoid levels increased under NaCl stress in Verte, but remained unchanged in Romaine. Chlorogenic acid (CGA), a soluble polyphenol abundantly present in leaves, was the only phenolic acid that accumulated significantly in both varieties and was predominant under salinity. Remarkably, CGA was more prominent in Verte than Romaine at moderate salinity levels (100 mM). Foliar flavonoid levels were also differentially increased in both seedling types grown under 100 mM NaCl, but dropped significantly in both varieties under 200 mM NaCl. Germination, which was overall more salt-resistant in Romaine, was significantly increased under salt stress by application of low dosage (10–6 to10–5 M) of CGA to Verte, but not to Romaine. These results suggest that CGA is involved in modulating NaCl-induced oxidative-stress responses during seed germination in Verte.

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