Mercury effects on the early seedling of Paraserianthes falcataria (L.) Nielsen grew in hydroponic culture

The purpose of this research was to investigate the impact of various level of mercury on the early seedling growth of sengon, Paraserianthes falcataria (L.) Nielsen using hydroponic culture. The study was carried out in twenty replications under greenhouse condition. The mercury used in this study were provided as chloride salts. Eight concentrations (30, 40, 50, 60, 70, 80, 90 and 100 µM) were used in this study. For each treatment, the pH was adjusted to 4.5. Fourteen-day-old seedlings were exposed to HgCl2. Shoot and roots system of control and mercury-stress plants were harvested after 7 days of treatment. Seedling response to mercury stress was observed in the plant parts on the 3rd day after the treatment, and become severe on the 7th day. Results showed that 30 and 40 µM, the concentrations had minimum inhibitory effects on the seedling growth, respectively. The results also revealed both shoot and root dry weight of the treated seedling were sharply reduced as the mercury concentration increased to 60 µM. In a concentration of 70-100 µM the biomass dry weight was not much different. Research results show this plant can be considered as a strong candidate for a phytoremediation agent.