Morphological, physiological, and biochemical responses of Tunisian Urtica pilulifera L. under salt constraint

Urtica pilulifera from Urticaceae family was known by its benefit effects on human health and used in traditional medicine and recently largely used in pharmacological and food fields. In other hand, the salinization of soils is caused by several environmental factors leading to crop losses around the World. The ability of plants to tolerate salt stress is determined by multiple mechanisms. In the present study, morphological, physiological, and biochemical modulations in Urtica pilulifera under salt stress was evaluated to assess its tolerance or sensitization potential to salt stress using different concentrations of NaCl (0, 50, 100 and 150 mM). The studied parameters of Urtica pilulifera were evaluated by cultivating the plant on a hydroponic medium. Results showed that after 15 days of treatment, a reduction in plant growth was noted correlating with leaf chlorosis under 100 mM NaCl and an increased level of proline and soluble sugar. Regression analysis showed that the applied salt concentration was proportional with the activity of antioxidant enzymes including catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX), both on the arial and the root parts. Cellular damage induced by salinity is strongly correlated with the generation of reactive oxygen species, osmotic damage, and reduction in relative water content. Accelerated antioxidant activity and osmotic adjustment through training osmolytes, are effective salinity tolerance mechanisms developed by Urtica pilulifera. (C) 2021 SAAB. Published by Elsevier B.V. All rights reserved.