Effects of selenium combined with zinc amendment on zinc fractions and bioavailability in calcareous soil

Mingyue Xue; Dan Wang; Fei Zhou; Zekun Du; Hui Zhai; Mengke Wang; Quang Toan Dinh; Thi Anh Thu Tran; Huinan Li; Ying Yan; Dongli Liang

doi:10.1016/j.ecoenv.2019.110082

Effects of selenium combined with zinc amendment on zinc fractions and bioavailability in calcareous soil

Ecotoxicol Environ Saf. 2020 Mar 1:190:110082. doi: 10.1016/j.ecoenv.2019.110082. Epub 2019 Dec 16.

Authors

Affiliations

¹ College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China.
² College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, 712100, China. Electronic address: dlliang@nwsuaf.edu.cn.

PMID: 31855791
DOI: 10.1016/j.ecoenv.2019.110082

Abstract

Selenium (Se) and zinc (Zn) are two important trace elements for human being and animals. The interaction between Se and Zn on the bioavailability of Zn in soil is still unclear. Therefore, pot experiments exposed to different dosages of zinc sulfate (ZnSO₄) (0, 20, and 50 mg/kg soil) and sodium selenite (Na₂SeO₃) (0, 0.5, 1.0, and 2.5 mg/kg soil) were conducted to investigate the effects of selenite application on Zn bioavailability in calcareous soil and its related mechanisms. The total Zn content of different tissues (roots and shoots) of pak choi (Brassica chinensis L.) and the changes in Zn fraction distribution in soil before planting and after harvest were determined, and the mobility factor (M_F) and distribution index (D_I) of Zn in soils were calculated. In addition, the Pearson correlation and path analysis were conducted to clarify the relationships between Zn fractions in soil and the Zn uptake of pak choi. Results showed that Se amendment elevated soil Zn bioavailability at appropriate levels of Se and Zn. When 1.0 and 2.5 mg/kg of Se and 20 mg/kg of Zn were applied in soil, the proportion of exchangeable Zn (Ex-Zn) and Zn weakly bound to organic matter (Wbo-Zn) to the total content of Zn was significantly increased by 28.14%-82.52% compared with that of the corresponding single Zn treatment. Therefore, the Zn concentration in the shoots of pak choi was significantly increased by 27.2%-31.1%. High Zn (50 mg/kg) and Se co-amended treatments showed no significantly beneficial effect on the bioavailability of Zn. In addition, the potential available Zn content in soil (weakly bound to organic matter and carbonate bound Zn) and M_F and D_I values were all positively correlated with the Zn concentrations in pak choi, indicating that these indexes can be used to predict the bioavailability of Zn in soil. This study can provide a good reference for Se and Zn biofortification of plants in calcareous soil.

Keywords: Bioavailability; Fraction; Pak choi; Selenite; Zinc.

MeSH terms

Brassica / metabolism
Plant Roots / chemistry
Selenious Acid / chemistry
Selenium / chemistry*
Sodium Selenite / chemistry
Soil
Soil Pollutants / analysis
Soil Pollutants / chemistry*
Zinc / analysis
Zinc / chemistry*

Substances

Soil
Soil Pollutants
Selenious Acid
Selenium
Sodium Selenite
Zinc