Potential role of L-glutamic acid in mitigating cadmium toxicity in lentil (Lens culinaris Medik.) through modulating the antioxidant defence system and nutrient homeostasis

Abstract

Using phosphate fertilizers and wastewater as a source of irrigation and residuals from industries have considerably increased the level of cadmium (Cd) in soil which severely reduced the growth and yield of crop.L-glutamic acid (L-Glu), an amino acid, plays key roles in plant stress tolerance. Hence, the current study wasconducted to determine the potential role of L-Glu pre-treatment in alleviating Cd-induced toxicity in lentil(Lens culinaris Medik.). Lentil seedlings were exposed to two doses of Cd (1 and 2 mM CdCl2) with or without10 mM L-Glu pre-treatment. The results suggested that a high dose of Cd negatively affected the shoot dryweight, root dry weight, and photosynthetic pigments (chlorophylls and carotenoids). Furthermore, Cd stressinduced severe oxidative damage, a reduction in catalase (CAT) activity and ascorbate (AsA) content, andaccumulation of Cd in both the roots and shoots. Adding L-Glu protected the photosynthetic pigments of thelentil seedlings and thus improved the growth of the seedlings. In addition, L-Glu pre-treatment enhanced theascorbate (AsA) content; increased the activity of enzymes such as catalase, ascorbate peroxidase,monodehydroascorbate reductase, and glutathione peroxidase. L-Glu was also reduced Cd uptake andtranslocation, which in turn alleviated the oxidative damage in the Cd-stressed seedlings indicated the potentialrole of this chemical. Results suggest that pre-treatment with L-Glu reduces Cd toxicity in lentil seedlings byinhibiting Cd accumulation and by reducing oxidative damage