Exogenous hemin improves Cd2+ tolerance and remediation potential in Vigna radiata by intensifying the HO-1 mediated antioxidant defence system

Abstract

The present study evaluated the effects of exogenous hemin on cadmium toxicity in terms of metal accretion and stress resilience in Vigna radiata L. (Wilczek). One-week-old seedlings were treated with CdCl2 (50 μM) alone and in combination with hemin (0.5 mM) in half-strength Hoagland medium for 96 h. The optimum concentrations of Cd and hemin were determined on the basis of haem oxygenase-1 activity. The results demonstrated that under Cd stress, plants accumulated a considerable amount of metal in their tissues, and the accumulation was higher in roots than in leaves, which significantly reduced the plant biomass and chlorophyll content by increasing the oxidative stress (MDA and H2O2 content). However, hemin supplementation under Cd,-stress improved plant growth by enhancing the harvestable biomass and photosynthetic pigments, increasing antioxidant activities (SOD, APX, POD, HO-1 and proline), lowering oxidative damage and increasing Cd tolerance in plants. Furthermore, the application of hemin enhances the removal efficiency of Cd in V. radiata by increasing the uptake of Cd via roots and its translocation from roots to foliar tissues. Thus, the study suggests that hemin has the potential to improve the stress tolerance and phytoremediation ability of heavy metal-tolerant plants so that they can be used instead of hyperaccumulators for remediation of Cd-contaminated environments.

Role of Engineered Carbon Nanoparticles (CNPs) in Promoting Growth and Metabolism of Vigna radiata (L.) Wilczek: Insights into the Biochemical and Physiological Responses

“…To overcome the negative impact of CNPs, plants have a well-developed antioxidant system which comprises of several non-enzymatic (proline, carotenoids, thiols) and enzymatic antioxidants (ascorbate peroxidase, catalase, superoxide dismutase, guaiacol peroxidase, glutathione reductase, heme-oxygenase), that can scavenge the surplus ROS. Heme-oxygenase is a novel discovered enzyme in higher plants that works as an antioxidant against different environmental stress, namely salinity, UV-B and heavy metal stress [ 10 , 11 , 12 , 13 ]. The enzyme catalyzes the oxidative degradation of Fe (III) protoporphyrin IX to biliverdin IX (BV), carbon monoxide (CO) and iron in the presence of a reducing equivalent (NADPH) [ 14 , 15 , 16 ].…”

Nanofertilizer Possibilities for Healthy Soil, Water, and Food in Future: An Overview

“…The single-walled carbon nanotubes (SWCNTs) significantly transport and irreversibly localize within the lipid envelope of extracted plant chloroplasts, improving 3-fold higher photosynthetic efficiency compared with an increase in electron transport rate (Giraldo et al, 2014 ). The harmful effects of CNPs in plants may get mitigated by having a well-developed antioxidant system that includes several nonenzymatic molecules, such as proline, carotenoids, thiols, and enzymatic antioxidants, like APX, CAT, SOD, GPX, GR, and heme-oxygenase, that may scavenge the surplus ROS (Balestrasse et al, 2008 ; Mahawar et al, 2021 ). Furthermore, attempts are yet to be put in to explore the mechanism associated with CNM bioregulation.…”

Bioaccumulation and Tolerance Indices of Cadmium in Wheat Plants Grown in Cadmium-Spiked Soil: Health Risk Assessment

“…The European Food Safety Authority recommended the tolerable daily intake is 0.358 μg Cd kg −1 body weight, which is lower than the World Health Organization's (WHO's) recommended value (25 µg kg −1 BW month −1 ) (Jinadasa et al, 2019). Cadmium is a toxic trace metal that is detrimental to different cereal crops including wheat since it can typically block the essential plant nutrients transport in different plant organs, such as roots, shoots and grain during seedlings' emergence to through to their growth and developments stages (Mahawar et al, 2021). The bread wheat (Triticum aestivum L.) is the third most cultivable and earliest domesticated cereal crop worldwide, and it is grown in around 20% of cultivable agricultural soil globally (Mehta and Bharat, 2019).…”