MITIGATING ALUMINUM TOXICITY IN SEEDLINGS OF GLYCYRRHIZA GLABRA L. USING SILICON

Background: Silicon is a beneficial element for the plant, with the primary role in increasing plant resistance to heavy metals' toxicity and considering the importance of phytoremediation to remove heavy metals from contaminated soils. It could be used for the exogenous application for alleviating the harmful effects of heavy metals on the plant. Aim: This study aimed to investigate the role of Silicon in balancing the destructive effects of aluminum on Glycyrrhiza glabra L. Methods: the seedlings were grown under a hydroponic system using Long Ashton nutrient solution; the 15-day-old seedlings were exposed to Silicon (0, 0.5, 1.5 mM) for 110 days and afterward stressed by interactions of aluminum chloride (AlCl3.6H(2)O; 0, 100, 250, and 400 M). Result and Discussion: the interactive effects of Silicon significantly ameliorated the negative consequences of aluminum toxicity. The combination of Si 1.5 mM and Al 400 mu M produced the highest biomass in shoots (45.67 g). The simple effect of Si 1.5 mM (12.14 g) made the highest shoot dry weight. On the other hand, the highest quantity of root fresh and dry weight (12.52 and 3.22 g, respectively) was observed in Si 1.5 mM. Among the treatments, Si 0.5 mM + Al 100 mu M had the most stem height (38 cm) among interaction treatments. Similarly, photosynthetic pigments affected by Silicon, Al 250 mu M + Si 1.5 mM had the highest content of chlorophyll a (1.91 mu g/g FW), while Al 400 + 1.5 mM indicated the most increase in chlorophyll b (0.78 mu g/g FW) among interaction effects. This treatment by producing 0.663 mu g/g FW yielded the highest carotenoid content. The highest proline content in shoots and roots (69.54 and 81.46 mu g/g FW, respectively) were observed in the interaction of AI 400 mu M and Si 1.5 mM. Additionally, this treatment was observed to have the highest concentration of catalase (1.22 U/mg protein). The lowest malondialdehyde content was marked in Si 1.5 mM + Al 100 mu M (0.702 nM/g FW). Conclusion: overall, Glycyrrhiza Glabra L. seems to have high Al phytoremediation potential that can be enhanced with the exogenous application of a moderate Silicon level.