LEAD (Pb)-INHIBITED EARLY ROOT GROWTH IN WHEAT INVOLVES ALTERATIONS IN ASSOCIATED BIOCHEMICAL PROCESSES

Abstract

The present study investigated the effect of Lead (Pb; 50 and 500 μM) on biochemical alterations during the
early radicle growth. It was observed that Pb-exposure significantly enhanced the contents of water-soluble
proteins and carbohydrates in wheat radicle after 24 h in a dose-response manner. Proteins and carbohydrates
content increased by 2.3- and 3.5-folds, respectively at 500 μM Pb-exposure. On the other hand, the activities
of hydrolyzing enzymes proteases and amylases were drastically reduced. At 500 μM, activities of proteases,
α-amylases, and β−amylases decreased by 92, 55, and 82% respectively. In addition, Pb-exposures significantly
enhanced the activities of enzymes - peroxidases, polyphenol oxidases by 2.6- and 2.2- times, respectively,
over of control at 500μM Pb. Enhancement in the activities of these enzymes indicate their upregulation /
induction in response to Pb-induced toxicity in wheat radicle and provide protection. The study concludes
that Pb-induced toxicity in emerging wheat seedlings involves the biochemical alterations in terms of
macromolecules and the activities of related enzymes to cope with the Pb-stress.