Root zone selenium reduces cadmium toxicity by modulating tissue-specific growth and metabolism in maize (Zea mays L.)

ABSTRACT

The effects of selenium (Se) cadmium (Cd) interactions on plant growth and metabolism are not fully clear. In the present study, we assessed whether Se could alleviate the toxic effects of Cd on growth and metabolism of maize. Seeds of maize variety FH-985 were sown in pots filled with sand treated with CdCl₂ (0, 50 and 100 µM) and Se (0, 2 and 4 mg L⁻¹) through Hoagland’s nutrient solution. Low Se (2 mg L⁻¹) increased germination percentage and rate, while high Se (4 mg L⁻¹) increased fresh and dry biomass under Cd stress. Interestingly, all Se concentrations were effective in alleviating the toxic effects of Cd on photosynthetic pigments, whereas higher Se mitigated the Cd-induced oxidative stress and increased flavonoids both in the shoots and roots while phenolics in the roots. The results demonstrated that root zone Se altered tissue-specific primary metabolism in maize. Furthermore, low Se mitigated the Cd-induced decrease in total proteins in the root. Overall, Se-mediated decrease in the oxidative stress in the shoots while increase of secondary metabolites in the roots helped the plants to grow faster at early growth stage and caused increase in the biomass under different Cd regimes.

KEYWORDS:

• Cd toxicity
• oxidative stress
• Cd–Se interactions
• secondary metabolites
• growth

Conflict of interest

The authors declare that they have no conflict of interest.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research presented in this paper was partially supported by Higher Education Commission (HEC), Islamabad, Pakistan, through Project grants 20-1522/R&D/09; 20-1523/R&D/10 to MI.