Increased fluctuation of sulfur alleviates cadmium toxicity and exacerbates the expansion of Spartina alterniflora in coastal wetlands

Yueming Wu; Zhanrui Leng; Jian Li; Hui Jia; Chongling Yan; Hualong Hong; Qiang Wang; Yanyan Lu; Daolin Du

doi:10.1016/j.envpol.2021.118399

Increased fluctuation of sulfur alleviates cadmium toxicity and exacerbates the expansion of Spartina alterniflora in coastal wetlands

Environ Pollut. 2022 Jan 1;292(Pt B):118399. doi: 10.1016/j.envpol.2021.118399. Epub 2021 Oct 22.

Authors

Yueming Wu¹, Zhanrui Leng¹, Jian Li², Hui Jia³, Chongling Yan⁴, Hualong Hong⁴, Qiang Wang⁵, Yanyan Lu¹, Daolin Du¹

Affiliations

¹ Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China.
² Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China. Electronic address: jianli@ujs.edu.cn.
³ Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China.
⁴ State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102, China.
⁵ State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China.

PMID: 34695515
DOI: 10.1016/j.envpol.2021.118399

Abstract

Evidence suggests that the invasion of Spartina alterniflora (S. alterniflora) poses potentially serious risks to the stability of coastal wetlands, an ecosystem that is extremely vulnerable to both biological and non-biological threats. However, the effects and mechanisms of sulfur (S) in mediating the growth and expansion of S. alterniflora are poorly understood, particularly when sediments are contaminated with cadmium (Cd). A 6-month greenhouse study was conducted to evaluate the mediating effect of S on Cd tolerance and growth of S. alterniflora. Treatments consisted of a factorial combination of three S rates (applied as Na₂SO₄; 0, 500, 1000 mg kg^-1 dry weight (DW), as S₀, S₅₀₀, and S₁₀₀₀) and four Cd rates (applied as CdCl₂; 0, 1, 2, 4 mg kg^-1 DW, as Cd₀, Cd₁, Cd₂, and Cd₄). Results showed that although the exogenous S supply obviously increased Cd accumulation in roots (up to 71.22 ± 6.43 mg kg^-1 DW) due to the decrease of Fe concentration in iron plaque (down to 4.02 ± 1.18 mg g^-1 DW), biomass reduction and oxidative stress in plant tissues were significantly alleviated. The addition of S significantly up-regulated the concentration of compounds related to Cd tolerance, including proline and glutathione. Therefore, the translocation of Cd was restricted, and plant growth was not impacted. The present study demonstrated that the exogenous sulfur supply could promote the growth of S. alterniflora and enhance its tolerance to Cd. Therefore, under the effects of S. alterniflora, the increased fluctuations of S pool caused by the release and deposition of S might further exacerbate S. alterniflora expansion in Cd contaminated coastal wetlands.

Keywords: Cadmium; Coastal wetlands; Plant invasion; Spartina alterniflora; Sulfur.

MeSH terms

Cadmium* / toxicity
China
Ecosystem
Introduced Species
Poaceae
Sulfur
Wetlands*

Substances

Cadmium
Sulfur