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

Jannatul Fardus,Masayuki Fujita,Md Shahadat Hossain

doi:10.15835/nbha49412485

Jannatul Fardus, Masayuki Fujita + Show 1 more

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https://doi.org/10.15835/nbha49412485

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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 was conducted 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 without 10 mM L-Glu pre-treatment. The results suggested that a high dose of Cd negatively affected the shoot dry weight, root dry weight, and photosynthetic pigments (chlorophylls and carotenoids). Furthermore, Cd stress induced severe oxidative damage, a reduction in catalase (CAT) activity and ascorbate (AsA) content, and accumulation of Cd in both the roots and shoots. Adding L-Glu protected the photosynthetic pigments of the lentil seedlings and thus improved the growth of the seedlings. In addition, L-Glu pre-treatment enhanced the ascorbate (AsA) content; increased the activity of enzymes such as catalase, ascorbate peroxidase, monodehydroascorbate reductase, and glutathione peroxidase. L-Glu was also reduced Cd uptake and translocation, which in turn alleviated the oxidative damage in the Cd-stressed seedlings indicated the potential role of this chemical. Results suggest that pre-treatment with L-Glu reduces Cd toxicity in lentil seedlings by inhibiting Cd accumulation and by reducing oxidative damage.

Highlights

Cadmium (Cd) has been considered as a highly toxic pollutant amongst other toxic metals that contaminate soil through injudicious use of phosphate fertilizers and pesticides, and disposal of sewage sludge into the environment (He et al, 2016; Khan et al, 2017)
Adding L-glutamic acid (L-Glu) increased the dry weight of the shoots (10 and 19%) and roots (20 and 48%) significantly in response to both levels of Cd compared with the Cd-stressed seedlings (Table 1)
Our current study revealed that exogenous application of l-Glu improved the accumulation and translocation of K+, Ca2+, and Mg2+ in the leaves, shoots, and roots of the lentil seedlings under both Cd concentrations, indicating that L-Glu limits the accumulation of Cd (Supplementary Figure 3a-i)

Summary

Introduction

Cadmium (Cd) has been considered as a highly toxic pollutant amongst other toxic metals that contaminate soil through injudicious use of phosphate fertilizers and pesticides, and disposal of sewage sludge into the environment (He et al, 2016; Khan et al, 2017). Cadmium serves no biological function in plants, so the growth and productivity of plants growing in Cd-contaminated soil are severely affected. Received in revised form: 05 Oct 2021. From Volume 49, Issue 1, 2021, Notulae Botanicae Horti Agrobotanici Cluj-Napoca journal uses article numbers in place of the traditional method of continuous pagination through the volume. The journal will continue to appear quarterly, as before, with four annual numbers

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