Different antioxidant responses to salt stress in two different provenances of Carthamus tinctorius L.

Abstract

Seedlings of two Tunisian Carthamus tinctorius L. provenances (Kairouan and Tazarka) differing in salt sensitivity were hydroponically grown at 0 and 50 mM NaCl over 21 days. Leaves of Kairouan (saltsensitive) showed a 48% restriction in their growth at 50 mM NaCl although they accumulated less sodium than those of Tazarka (less salt-sensitive) that maintained an unchanged growth. Salt treatment induced oxidative stress in C. tinctorius and the effect was more pronounced in the leaves of the more salt sensitive provenance, Kairouan. Both provenances exhibited a stimulation of antioxidant enzyme activities with higher catalase (CAT) and superoxide dismutase (SOD) activities in Tazarka and higher peroxidase (POD) activity in Kairouan. But, it seems that antioxidant activities were more correlated with polyphenol content. Actually, leaves of Tazarka experienced higher polyphenol and antioxidant activity than Kairouan at 50 mM NaCl. Hence, moderate salinity (3 g NaCl L -1 ) enhanced bioactive molecule yield in the less salt sensitive provenance, Tazarka. In addition, C. tinctorius was found rich in ascorbic acid, but the moderate salt stress enhanced its production only in the sensitive provenance.

How Salt Stress Represses the Biosynthesis of Marrubiin and Disturbs the Antioxidant Activity of Marrubium Vulgare L

“…According to [31], the drastic effect of salinity (75 mM) on TPC of Salvia sclarea L. may be due to a less efficient ROS as a result of an imbalance between ROS and antioxidant formation, leading to the installation of the oxidative stress. However, this trend is contradictory to that observed in cucumber [46], Carthamus tinctorius [47,48], Salvia officinalis [30], and Origanum majorana , Zn 2+ contents (µg/g DW) of M. vulgare subjected to different NaCl concentrations (0, 25, 50 and 100 mM) during 5 months. [49].…”

Reactive Oxygen Species, Oxidative Damage, and Antioxidative Defense Mechanism in Plants under Stressful Conditions

“…Elevated CO 2 mitigates the oxidative stress caused by salinity, involving lower ROS generation and a better maintenance of redox homeostasis as a consequence of higher assimilation rates and lower photorespiration [243]. Salinity-induced ROS disrupt normal metabolism through lipid peroxidation, denaturing proteins, and nucleic acids in several plant species [12,242,244]. Differential genomic and proteomic screenings carried out in Physcomitrella patens plants showed that they responded to salinity stress by upregulating a large number of genes involved in antioxidant defense mechanism [245] suggesting that the antioxidative system may play a crucial role in protecting cells from oxidative damage following exposure to salinity stress in P. patens.…”

Saline stress enhanced accumulation of leaf phenolics in honeysuckle ( Lonicera japonica Thunb.) without induction of oxidative stress

“…Thus, as a traditional viewpoint, phenolic compounds are defined as secondary antioxidants, and play an assisting role in detoxifying ROS, when the primary antioxidant system is depressed under severe stress (Fini et al, 2011). However, this traditional viewpoint has been challenged recently, because moderate saline stress is more liable to induce accumulation of phenolics in plants without severe oxidative stress and depression of antioxidant system (Abrol et al, 2012;Karray-Bouraoui et al, 2010;Ksouri et al, 2007;Shao et al, 2015;Zhao et al, 2015). Therefore, the relation between antioxidant system and phenolic metabolites in resisting oxidative stress is still not clear.…”

“…In Chinese, honeysuckle is a traditional medicinal plant, and has been widely used in healthcare, food and cosmetics industries. At present, studies attach importance to salt-induced changes in concentrations of bioactive phenolic compounds in medicinal plants (Colla et al, 2013;Karray-Bouraoui et al, 2010;Shao et al, 2015;Zhao et al, 2015). However, antioxidant mechanisms of phenolics in vivo are often overlooked, and the relation between accumulation of phenolics and antioxidant system induction under saline stress is less concerned.…”