Effect of Silicon on Cadmium Absorption of Cucumber Organs in Calcareous Soil

Abstract

For plant growth, cadmium (Cd) is a toxic and easily accumulated element but silicon (Si) is beneficial. To explore the alleviating effect of Si on Cd toxicity to plants in Cd-contaminated calcareous soil, the effect of Si on Cd absorption was investigated for cucumber organs in pot experiments. The Cd concentration of cucumber organs using an atomic absorption spectrophotometer. The Si significantly inhibited Cd uptake by cucumber organs and was most effective for Si application of 100–200 mg kg−1. On the whole, the translocation factors of stems and leaves did not vary significantly, but substantially varied in fruit. The distribution pattern of Cd content in different cucumber organs follows: root > stem > leaf > > fruit. For Cd content in soil ≤ 3 mg kg−1, the Cd content in cucumber fruit was lower than the maximum limit of Cd content in fresh vegetables in China (GB2762-2017) for Si application of 100–300 mg kg−1. However, with the Cd treatment of 5 mg kg−1, the content of Cd in cucumber fruit exceeded this limit, even though Si alleviated Cd toxicity to some extent. Therefore, Si had a substantial alleviating effect on Cd uptake in cucumber, effectively reduced Cd toxicity to cucumber in calcareous soil. The study may help us understand the mechanism for silicon-mediated Cd tolerance in calcareous soil and provide theoretical basis for the application of silicon in the production of crops in alkaline soil polluted by Cd.