Enhancing Cd and Pb tolerance of Robinia pseudoacacia (black locust) by regulating antioxidant defense system, macroelement uptake and microstructure.

This article investigates the physiological, biochemical, and microstructural responses of the woody plant Robinia pseudoacacia (black locust) to soil co-contaminated with cadmium (Cd) and lead (Pb), assessing its potential for phytoremediation. The study found that black locust exhibits strong tolerance to combined Cd and Pb stress by regulating antioxidant enzyme activities, macroelement (potassium, calcium, magnesium) uptake, and microstructural adaptations such as thickened cell walls and restricted heavy metal transport via sieve tubes in roots and stems. Cd and Pb primarily accumulated in the roots, indicating black locust's suitability for phytostabilization of contaminated soils. Additionally, black locust maintained soil enzyme activities (urease, acid phosphatase, sucrase) during phytoremediation, suggesting its role in preserving soil health under heavy metal stress.