Effect of arsenic on nitrogen assimilatory enzymes in germinating rice seeds

The effect of arsenic on activities of enzymes associated with nitrogen assimilation viz. nitrate reductase, nitrite reductase, glutamine synthetase, glutamate dehydrogenases and aminotransferases was observed in endosperms as well as embryoaxes of seeds of two rice cvs. Malviya-36 and Pant-12 germinated under 25 and 50 μM AS₂O₃ in the medium. Results suggest that inhibition in the activity of key NO⁻₃ assimilatory enzymes limit the assimilation of NO⁻₃ by growing embryoaxes thereby leading to reduction in vigour of seedlings, while increased activity of glutamate dehydrogenase and aminotransferase appears to provide adaptational significance to the seeds germinating under As-polluted conditions.