Author(s)

Juliana Sarangthem, Sonal Dhamgaye, Rekha Gadre^*

School of Biochemistry, Devi Ahilya University, Takshashila Campus, Khandwa road, Indore, India.

Supply of CdCl₂ in the presence of NH₄NO₃ to excised etiolated maize leaf segments during greening decreased the glutamine synthetase and nicotinamide adenine dinucleotide reduced (NADH) dependent glutamate synthase activities, while the ferredoxin (Fd) dependent glutamate synthase and glutamate dehydrogenase activities were increased. Inclusion of inorganic nitrogen, metabolites and the inhibitor influenced the effect of Cd on glutamine synthetase activity. The % inhibition of activity caused by Cd was higher with NO₃^- but lower with NH₄⁺. Glutamine, 2-oxoglutarate, glutathione and sucrose decreased the % inhibition by Cd with the more prominent effect with glutamine and sucrose. Methionine sulfoximine exerted a more prominent effect for + Cd enzyme at lower concentration. The results indicate the involvement of reciprocal effects of Cd on glutamine synthetase and glutamate dehydrogenase activities and also on NADH- and Fd-glutamate synthase activities. For the inhibitory effect of Cd on glutamine synthetase activity, NH₄⁺, glutamine, 2-oxoglutarate, glutathione and sucrose exerted a protective effect with the sucrose being most effective.

Glutamine Synthetase, Cd Effects, Ammonia Assimilation, Zea mays, Maize Leaves

Sarangthem, J. , Dhamgaye, S. and Gadre, R. (2017) Cadmium Effects on Enzymes of Ammonia Assimilation in Excised Etiolated Maize Leaf Segments during Greening: A Mechanistic Approach. American Journal of Plant Sciences, 8, 1399-1410. doi: 10.4236/ajps.2017.86095.