Physiological resistance of Sasa argenteostriata (Regel) E.G. Camus in response to high-concentration soil Pb stress

Abstract

Dwarf bamboo Sasa argenteostriata (Regel) E.G. Camus has previously been considered as potential plant for metal phytoremediation. However, the dynamic responses and correlations among physiological resistances to high-concentration Pb exposure have not been described to date. This study conducted four Pb treatments (0, 1500, 3000, and 4500 mg kg–1) to examine the physiological resistance responses at days 7, 14, and 21. The findings showed that S. argenteostriata can regulate both the enzymatic system and the nonenzymatic system to synergistically overcome Pb damage. In addition, a significant positive correlation was found between enzymes and nonenzymatic substances, which were particularly apparent with regard to the superoxide dismutase (SOD) activities with phytochelatins (PCs) levels, peroxidase (POD), and glutathione reductase (GR) activities with glutathione (GSH) levels, as well as catalase (CAT) and ascorbate peroxidase (APX) activities with soluble protein (SP) levels. Furthermore, Pb concentration was the main factor that induced the physiological responses of S. argenteostriata to Pb stress. The antioxidant enzyme system and the AsA–GSH cycle were dominant resistance mechanisms under 1500 mg kg–1 Pb. AsA–GSH cycle and plant cell chelation were dominant resistance mechanisms under 3000 mg kg–1 Pb. Antioxidant enzymes and plant cell chelation were dominant resistance mechanisms under 4500 mg kg–1 Pb. This study provides comprehensive evidence regarding how both enzymatic and nonenzymatic systems of S. argenteostriata cooperate to alleviate the high-concentration soil Pb stress. The results highlight the environmental remediation potential of this species for Pb-contaminated media.