Abstract: The effects of Ni deficiency on growth. activitles of urease and glutamine nynthetuse, the contents of urea and total N in rice plants were studied in solution culture when ammonium nitrate and urea as N sources- The results showed that the growth of rice plant was not affected by Nl deflclency when ammonlum nlttate .as N source. but largely lnhlblted when urea as N source- The actlvltles of urease ln the Nl deflclency plants were very low. The actlvltles of glutamlne Synthetuse were not influenced by the treatments except that its actlvlty ln the plants of urea(-Ni) was decreased. The urea contents were hlgher ln the Nl deflclency plants. eSPeclally urea accumulat6d ln the shoot of urea(-Ni). plants. The total N content was decreased ln the plants of urea(-Nll compared wlth other treatInents.