Effect of Different Forms of Selenium on the Physiological Response and the Cadmium Uptake by Rice under Cadmium Stress.

Haizhao Xu,Jingmao Xu,Yanyan Wei,Minghua Gu,M J I Shohag,Jinpeng Yan,Yan Qin

doi:10.3390/ijerph17196991

Abstract

Cadmium (Cd) is a pollutant toxic to plants and a potential threat to human health. Selenium (Se), though not essential for plants, has beneficial effects on plants under abiotic stress. A hydroponic experiment was conducted to investigate the impact of different forms of Se (Nano-Se, selenite, selenate, and SeMet) on accumulation, subcellular distribution, and chemical forms of Cd, as well as oxidative stress in rice seedlings. Cd (20 μmol·L−1) treatment significantly decreased biomass accumulation and chlorophyll content. The application of all Se forms, except selenate, mitigated the adverse effects of Cd on growth and chlorophyll content. The application of selenite, Nano-Se, and SeMet decreased root and shoot Cd concentrations as well as root-to-shoot Cd translocation in rice seedlings. Selenate application decreased shoot Cd concentration and root-to-shoot Cd translocation with no effect on root Cd concentration. Accordingly, Se increased the sequestration of Cd in the cell wall and vacuoles and decreased the active chemical form of Cd in rice seedlings. SeMet was the most effective supplement that decreased Cd concentration and enhanced Se concentration in the roots and shoots of rice seedlings. All forms of Se further enhanced catalase (CAT) and glutathione peroxidase (GSH-Px) activities and inhibited MDA accumulation. To conclude, Se influenced Cd accumulation and translocation in rice seedlings by altering the subcellular distribution, chemical forms, and antioxidant defense system under Cd stress. These effects were highly significant with SeMet treatment, probably due to better absorption and utilization by the plant.

Highlights

Cadmium (Cd) is one of the most toxic heavy metals, and Cd soil pollution has become a serious global concern [1]
The root and shoot dry weights of rice seedlings treated with Cd were significantly reduced by 23% and 30%, respectively (Table 1)
The shoot dry weight of rice seedlings treated with SeMet and Se (IV) significantly increased by 51% and 96%, respectively, compared with the seedlings treated with Cd alone

Summary

Introduction

Cadmium (Cd) is one of the most toxic heavy metals, and Cd soil pollution has become a serious global concern [1]. A high concentration of Cd in plants causes oxidative damage via an increase in the formation of reactive oxygen species (ROS) and the effect on activities of antioxidant enzymes [3,4,5]. Rice (Oryza sativa L.) is one of the most important cereal crops globally, and about half of the world’s population depends on it for food. Rice is considered an efficient Cd accumulator due to its ability to absorb Cd from the soil and further translocate into the grain [6]

Methods

Results

Discussion

Conclusion