Metal Toxicity Reduction on Seed Germination and Seedling Growth of Raphanus sp. and Arabidopsis sp. Using Date Seed Biochar

The date seeds (DS) biochar produced at 550°C was found to be appropriate for remediation of metal-contaminated water. This was evident in the data, which showed that applying the biochar to Raphanus sp. and Arabidopsis sp. reduced metal stress and toxicity. The LC50 of all tested metals solutions on seed germination was increased significantly (P<0.05) in Raphanus sp. by 10.4, 2.3, 5, 1.8, and 3 folds, respectively, for Cu, Zn, Cd, Pb, and metals combination, and by 5, 3.4, 6, 5.5, and 2.5 folds in Arabidopsis sp. For seedling growth, the DS biochar enhanced the LC50 significantly (P<0.05) of the same metals in Raphanus sp. by 9.6, 9.2, 13.8, 12.1, and 1.6 folds, and in Arabidopsis sp. by 7, 3, 2.3, 2.9, and 2.7 folds, respectively. The LC of all metals was increased by 1.5 to 8 times and 1.5 to 12 times, respectively, for the seed germination and seedling growth of Raphanus sp. and Arabidopsis sp. Both plants were able to grow shoots at higher metal concentrations when the DS biochar was employed, as compared to the case when no DS biochar was utilized. In terms of shoot length, similar results were achieved, with the DS biochar application significantly enhancing shoot length (P<0.05), as compared to the case when no biochar was applied. Despite the fact that Arabidopsis sp. was more sensitive to metals than Raphanus sp., both plants raised their RGR and TI and reduced their phytotoxicity values in all metals following the DS biochar application, and sprouted at higher metal concentrations than before. These findings introduce a successful eco-friendly adsorbent for metal removal from aquatic environments, paving the way for more investigations.