The effects of simulated acid rain and cadmium-containing atmospheric fine particulate matter on the pakchoi (Brassica campestris. L) seedlings growth and physiology

ABSTRACT

Acid rain (AR) and atmospheric particulate matter (APM) are important environmental issues that often occur simultaneously in agricultural regions, the combined pollution of AR and atmospheric fine particles (PM_2.5) containing heavy metals has negatively affected the growth of seedlings and has become a hot research topic. In this paper, we established exposure scenarios to simulate the AR and the cadmium-containing PM_2.5 (PM_2.5-Cd) pollutions. Under the scenarios, hazardous impacts of AR and PM_2.5-Cd on growth, physiological and biochemical characteristics of pakchoi were evaluated. After being exposed simulated AR and PM_2.5-Cd for 21 days, our results indicate that: single treatment with either AR (pH 5.5) or PM_2.5-Cd, or a combined treatment of AR (pH 5.5) and PM_2.5-Cd (150, 300 μg·m⁻³) increased the growth of pack hoi seedlings. Combined treatments with low-acidity AR (pH 3.5) and PM_2.5-Cd (500 μg·m⁻³), significantly decreased the growth and the Soil and Plant Analyzer Development (SPAD) of pakchoi, and it also induced a significantly increase in foliar MDA content and catalase (CAT) activity, while decreasing peroxidase (POD) and superoxide dismutase (SOD) activity. The Cd concentration of leaves increased with an increasing PM_2.5-Cd concentration. Correlation analysis indicated that the growth and SPAD of pakchoi were highly correlated with the foliar MDA content and enzyme activities under the combined treatments with AR and PM_2.5-Cd treatment. Our results might serve as a guide to increase agricultural production and food crop safety in areas with high levels of AR and PM_2.5 pollution.

KEY WORDS:

• Acid rain
• cadmium
• fine particulate matter
• physiological
• biochemical

Acknowledgments

We thank the Hefei Guangdian Metrology & Testing Co., LTD for detect the concentration of Cd. We are grateful to Dr. Songlin Ruan (Hangzhou Academy of Agricultural Sciences) for kind help and useful advices for data analysis. This work was financially supported by Natural science foundation of Zhejiang Province (LQ20C030007), and Jiangsu Planned Projects for Postdoctoral Research Fund (2018K064B).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was funded by the Natural science foundation of Zhejiang Province (Key Projects of National Natural Science Foundation of Zhejiang Province LQ20C030007), and Jiangsu Planned Projects for Postdoctoral Research Fund (Jiangsu Planned Projects for Postdoctoral Research Funds 2018K064B).