Detection of Phytochelatin and Glutathione in Seagrass Thalassia hemprichii as a Detoxification Mechanism Due to Lead Heavy Metal Exposure

Abstract

Seagrass Thalassia hemprichii is used to study lead (Pb) metal accumulation and synthesis of phytochelatin (PC) and glutathione (GSH) as defense mechanisms against lead toxicity. The plants were exposed by lead (Pb (NO₃)₂) metal in some concentrations (0, 5, 15 and 25 ppm) for some periods of time (1, 2, 3 and 4 weeks). The contents of lead (Pb), phytochelatin (PC) and glutathione (GSH) are analyzed in leaf and root tissue. Lead accumulation in seagrass depends on the greatness of metal concentration and length of exposure time where the root accumulates lead higher than the leaf. Glutathione is produced higher in the root during lead exposure, while phytochelatin is produced in week 1 and 2. Then, production of phytochelatin turns to higher in the leaf in week 3, although it decreases in week 4. Phytochelatin and glutathione are formed at different retention time in UPLC, when glutathione content is formed earlier and lower than phytochelatin. The study not only reveals that content formation of phytochelatin (PC) and glutathione (GSH) occurs to respond Pb metal, but also shows that production of PC and GSH correlates significantly to Pb metal accumulation in the root and leaf of T. hemprichii. Therefore, in short, formation of PC and GSH, for sure, is a part of defense mechanisms conducted by seagrass T. hemprichii to protect itself against Pb metal toxicity.