Elevated Water Temperature Mitigates the Inhibitory Effect of Tetracycline, a Common Antibiotic, on the Wetland Invasive Plant Alternanthera philoxeroides

Abstract

Antibiotic pollution and rising water temperature collectively pose serious challenges to wetlands. However, how invasive plants respond to such combined stressors remains poorly understood. This study examined the growth and physiological responses of Alternanthera philoxeroides, a widespread invasive plant in China, to tetracycline hydrochloride (TC) at four concentrations (0, 2, 20, and 200 mg L⁻¹) under two water temperature conditions (20°C and 35°C). The results indicated that high TC concentrations (20 and 200 mg L⁻¹) significantly inhibited plant growth and reduced chlorophyll content, while increasing oxidative stress as reflected by increased malondialdehyde (MDA) levels. In contrast, elevated temperature (35°C) enhanced growth performance and reduced oxidative damage. Notably, elevated water temperature reduced the inhibitory effects of TC on A. philoxeroides. These findings suggest that warming may facilitate the invasion of A. philoxeroides in antibiotic-polluted wetlands. This study provides a critical perspective for predicting and managing plant invasions under global change and emphasizes the importance of considering interactive stressors in ecological risk assessment.