Soil Cadmium Regulates Antioxidases in Sorghum

The regulatory mechanism of soil cadmium (Cd) on antioxidases in sorghum was studied using 3 sorghum species viz., sweet sorghum [Sorghum bicolor (L.)] Moench. cv. Hunnigreen, sorghum hybrid sudangrass (Sorghum bicolor × S. sudanense, cv. Everlush) and sudangrass [Sorghum sudanense (Piper) Stapf cv. Xinjiang]. The results showed that low concentrations of Cd2+ (≤ 10 mg kg-1) induced the activities of 4 antioxidases in leaves of the 3 species of sorghum, but high Cd2+ concentrations (≥ 50 mg kg-1) significantly reduced the activities of all the four antioxidases. The glutathione (GSH) contents in leaves of the 3 species of sorghum correlated positively with the Cd2+ concentrations. The maximum antioxidase activities were observed at the elongation stage of sorghum during the whole growth period.