In-vitro evaluation of resistance to trace metals in the early development stage of the Mediterranean endemic Ballota hirsuta Benth. A critical approach for large-scale cultivation and environmental safety
摘要
The increasing incorporation of trace metals (TMs) into the soils has raised significant concerns regarding the ecosystem functioning and environmental safety. The toxicity caused by TMs can disrupt the cellular mechanisms of many organisms, making the protective measures for preserving the environment an urgent imperative. Utilizing native species, especially TM hyper-tolerant plants, could be important for restoring and bioremediating the degraded lands. In this investigation, the impact of 0, 50, 100, 150, and 200 mg L–1 of Pb, Cr, Ni, and Cd on seed germination capacity, seedling performance, and total protein levels of Ballota hirsuta (Benth.) was tested in a soilless controlled medium. Seeds treated with a moderate concentration (50 mg L–1) of TM showed a resistance and germination exceeded 80% due to either seed coat barrier or ion compartmentalization that prevents metallic elements from inhibiting the cell division and metabolism. However, the seeds treated with higher concentrations of Ni and Cd exhibited germination inhibition compared to those resistant to Pb and Cr. In general, B. hirsuta seedling development was sensitive to Cr, Ni and Cd compared to the tolerable Pb treatment. The protein accumulation was less affected by lead, with no significant impact detected between the Pb’s applied concentrations (p > 0.05, Tukey’s test). The ecological adaptation to prolong seed germination in B. hirsuta may contribute to restoring Pb-dominated soils in the Mediterranean basin. In addition, the results suggest that the studied taxon could be a promising candidate for further investigation in phytoremediation strategies.