Rapid effect of copper on lignin biosynthesis in soybean roots

Copper (Cu)-treated soybean (Glycine max) seedling showed significant inhibition in soybean root growth, and enhancement in peroxidase and laccase activity. The inhibition in root growth correlated with the increase of H2O2 levels, and activities of peroxidase and laccase. The enhancement of the activities of peroxidase (pI 8.9, pI 8.3, pI 7.7, pI 6.5, pI 5.6, and pI 4.4) and laccase (pI 9.2, pI 8.3, pI 7.2, pI 4.4, and pI 4.2) was accompanied by the increase of lignin contents in Cu-treated tissues. We suggested that laccases are responsible for lignin biosynthesis during the early stage in Cu-treated tissues. As the incubation time of Cu treatment was prolonged, laccases and peroxidases (POD) work cooperatively in lignin biosynthesis. (C) 2004 Published by Elsevier Ireland Ltd.