One month old C4 succulent Portulaca oleracea Linn was water stressed for 4, 8 
and 15 days (d). There was significant increase in the activities of enzymes, nitrate and 
nitrite reductases due to 8 d of water stress as compared to control. Activities of the 
enzymes glutamic oxaloacetic transaminase and glutamic pyruvic transaminase were 
also increased in the plants water stressed. Significant accumulation of nitrate and 
nitrite was observed in the water stressed plants. However, there was no significant 
change in the proline content of the plants. The amount of total soluble proteins was 
significantly increased in the root and leaves due to 8 d of water stress. Leaf protein 
profile (SDS-PAGE) revealed that 15 and 16 kD proteins were exclusive in the leaves 
of plants water stressed for 4 and 15 d. These alterations in the nitrogen metabolism of 
this nitrophilous plant for the adaptation to water stress have been discussed.