Minimizing Heavy Metal Accumulation in Edible Parts of Lettuce Plant

Abstract

The experiment was conducted to reduce the buildup of heavy metals in lettuce plants grown in contaminated soil. Lettuce plants cv. Nader were cultivated on polluted soil in black polyethylene bags with or without the addition of biochar, rice straw, Pseudomonas fluorescens, biochar + rice straw, biochar + P. fluorescens, rice straw + P. fluorescens, and biochar + rice straw + P. fluorescens, and unpolluted soil as a control. The experiments were conducted in 2019 and 2020 seasons at the Vegetable Farm, Faculty of Agriculture, Ain Shams University, Shubra El Kheima, Qalyubia Governorate, Egypt. The treatments were distributed in a completely randomized design with three replicates. The results indicated that cultivating lettuce in polluted soil had negative effects on plant growth compared to the unpolluted soil. Application of the treatments improved the vegetative growth parameters. The results also showed that lettuce plants grown in heavy metal-polluted soil had lower values of vegetative growth parameters than those grown in polluted soil treated with biochar, rice straw, or P. fluorescens, and the interaction between them. When compared to bacterial inoculation treatment, the application of biochar and/or rice straw on lettuce plants grown in heavy metal-contaminated soil enhanced growth and leaf nutrient contents, while heavy metal contents decreased. The findings demonstrated that heavy metal-contaminated soil treated with biochar alone or in combination with rice straw and/or bacterial inoculation were effective in reducing the content of heavy metals in plant leaves and attenuating the harmful effects of heavy metals on grown lettuce plants.