Effects of Exogenous Spd on NO₃^--N,NH₄⁺-N Contents and Nitrate Reductase Activity of Salt Stressed Leaves and Roots of Cucumber Seedlings

The effects of exogenous Spd on NO₃^--N,NH₄⁺-N,Pro contents and NR activity of salt stressed leaves and roots of cucumber seedlings in hydroponic culture were studied.The results showed that exogenous Spd could reduce salt-stress-induced increase of NH₄⁺-N,Pro contents and reduce decrease of NO₃^--N contents and NR activity,and salt tolerant cucumber was less affected than salt sensitive cucumber.It is indicated that exogenous Spd could alleviate salt stress on cucumber seedlings.