Author(s)

Agapit Wouyou¹, Hermann Prodjinoto^1,2, Ahissou Séraphin Zanklan¹, Brigitte Vanpee², Stanley Lutts², Christophe Bernard Gandonou^1*

¹Unité de Recherche sur l’Adaptation des Plantes aux Stress Abiotiques, les Métabolites Secondaires et l’Amélioration des Productions Végétales, Laboratoire de Physiologie Végétale et d’Etude des Stress Environnementaux, Faculté des Sciences et Techniques (FAST/UAC), Tri Postal, Cotonou, Bénin.
²Groupe de Recherche en Physiologie végétale, Earth and Life Institute, ELI-A, Université Catholique de Louvain, Louvain-La-Neuve, Belgique.

Salinity is one of the major environmental constraints limiting agricultural productivity in the world. The effects of salt stress on growth, ions and organic solutes accumulation were investigated in two amaranth (Amaranthus cruentus) cultivars: Rouge (salt-resistant) and Locale (salt-sensitive). Young plants of these cultivars were exposed, in hydroponic system, to three concentrations of NaCl: 0, 30 and 90 mM. Growth parameters, ions, free proline and soluble sugars concentrations were determined after 2 weeks of stress. NaCl effect resulted in plant growth reduction in both cultivars but plants of cultivar Rouge were less affected compared to that of cv. Locale. Na⁺, proline and soluble sugars concentrations increased significantly in leaves and roots under salinity while K⁺, Ca²⁺ and Mg²⁺ concentrations decreased in both cultivars. Proline and soluble sugars increased significantly in leaves and roots of cultivar Locale whereas in cultivar Rouge, proline increase was significant only in roots and soluble sugars increase was significant only in leaves. The highest increase of Na⁺ concentration occurred in leaves of cv. Rouge coupled with the lowest reduction in K⁺ concentration. The highest increase of proline occurred in leaves of cultivar Locale whereas the highest increase of soluble sugars was observed in leaves of cultivar Rouge. The reduction of the Ca²⁺ concentration under salt stress was more accentuated in both leaves and roots of cultivar Rouge than cultivar Locale while cv. Rouge maintained higher content in Mg²⁺ either in leaves or in roots in the presence of NaCl than cultivar Locale. These results suggest an implication of Na⁺, K⁺ and Mg²⁺ in salt resistance in these cultivars and that soluble sugars may play an important role in salt-resistance in Amaranthus cruentus. However, proline appears as a symptom of injury in stressed plants rather than an indicator of resistance.

Growth, Ions Concentration, Osmolytes Accumulation, Amaranthus cruentus, Salt-Resistance Mechanism

Wouyou, A. , Prodjinoto, H. , Zanklan, A. , Vanpee, B. , Lutts, S. and Gandonou, C. (2019) Implication of Ions and Organic Solutes Accumulation in Amaranth (Amaranthus cruentus L.) Salinity Resistance. American Journal of Plant Sciences, 10, 2335-2353. doi: 10.4236/ajps.2019.1012162.