Alterations in Glutathione, Phytochelatin and Micronutrients of Corn Plants Exposed to Cadmium Stress at Different Time Periods

Phytochelatin (PC) and glutathione (GSH) are important internal strategy of plants to detoxifying heavy metal (HMs) stress. In this study, the effect of cadmium (Cd) concentrations (0, 10, 25 and 40 mu M) on GSH, PC, some micronutrients' concentration in corn plants, and the role of PC in detoxifying Cd was assayed in different exposure time periods (2, 4, 8, and 16 day). The results showed that exposing corn plants to different Cd concentrations and various time period, decreased the fresh weight of corn plants (4% to 31% for shoots and 11% to 32% for roots) and nutrient uptake rates (NUR). The increase in Cd concentrations increased GSH and PC biosynthesis in corn plants (GSH increased from 72 to 235 nmol g(-1) F.W and PC increased from 79 to 505 nmol g(-1) F.W) and positive correlation was observed (in the range of 0.67 to 0.99). The concentrations of GSH and PC decreased by increasing Cd exposure time periods and was more intensified at the highest Cd concentration (40 mu M). These results indicate that PC plays an effective but transient role in Cd detoxification and the levels of PC are related to Cd concentration in cytoplasm and its threshold limit.

Automated summary

Phytochelatin (PC) and glutathione (GSH) are important internal strategies of plants to detoxify heavy metal stress. This study investigated the effect of different cadmium (Cd) concentrations on PC, GSH, and nutrient uptake rates in corn plants. The results showed that increasing Cd concentrations led to higher PC and GSH biosynthesis, but longer exposure periods decreased their concentrations. This study highlights the transient role of PC in Cd detoxification and its relationship with cytoplasmic Cd concentration.