Arsenic Distribution, Accumulation and Tolerance Mechanisms of Typha angustifolia in Different Phenological Growth Stages.

Variations of phytoaccumulation and tolerance in different growth stages of plant are important factors for effective removal of pollutants in phytoremediation. The present work investigated arsenic (As) accumulation, As-tolerance and the physiological tolerance mechanisms of Typha angustifolia under different As-level during the seedling, fast-growing and breeding stages. The results showed that As mainly distributed in the underground part and total As accumulation increased with growth stages. Maximum growth rates under lower As occurred in seedling stage, whereas occurred in breeding stage under higher As. T. angustifolia exhibited the highest tolerance ability under 150 mg kg-1 As and tolerance index (TI) varied from seedling to breeding stages. During seedling stage, TI was affected by plant height (Hshoot) and net photosynthesis, which control biomass production. During fast-growing stage, Hshoot and root glutathione (GSH) co-regulated plant As-tolerance. During breeding stage, physiological metabolic processes, especially GSH-mediated processes, played a critical role in improving plant As-tolerance.