Study of the Inhibition of Cadmium Uptake in Lettuce with Cassava Residue Biochar

Abstract

Cadmium (Cd), as a non-essential metal element in the process of plant growth, is widely present in different environments, and cadmium pollutants are an important member of inorganic pollutants in Chinese soil. Biochar can be used to remediate heavy metal contaminated soil, which can restore soil. After treatment with biochar, the mobility and bioavailability of heavy metal ions are reduced, the absorption efficiency of heavy metal ions by plants is reduced, and the final yield is improved. In this study, through pot experiments, the effects of cassava residue biochar on the growth of lettuce in heavy metal cadmium contaminated soil, MDA content, antioxidant enzyme POD, SOD activity, and the accumulation of heavy metal cadmium were studied. The experiment found that the application of cassava residue biochar significantly promoted the accumulation of lettuce biomass in cadmium contaminated soil; the application of cassava residue biochar effectively reduced the content of malondialdehyde (MDA) in lettuce leaves in cadmium contaminated soil, alleviating the level of oxidative stress; the application of cassava residue biochar increased the activity of peroxidase (POD) and superoxide dismutase (SOD) in lettuce leaves, which helps to clear the accumulation of reactive oxygen species caused by cadmium stress; the application of cassava residue biochar reduced the accumulation of cadmium in lettuce leaves and roots, especially in lettuce roots. The accumulation of cadmium has significantly decreased. The results ultimately showed that the application of cassava residue biochar in cadmium contaminated soil can significantly promote the accumulation of lettuce biomass and effectively reduce the absorption of cadmium by lettuce. The research results indicate that cassava residue biochar is an efficient cadmium blocker for lettuce.