[Objective]The aim was to study the response mechanism of drought stress of wheat varieties in different drought-resistance species,and protect the effect of exogenous NO on oxidative damage and photosynthetic apparatus of wheat leaves under drought stress.[Method]Using low-resistance Yumai 949 and high-resistance Xiamai 5 as test materials,drought stress was carried out to seedlings in five-leaf stage with 15% PEG-6000,and then NO（0.75 mmol/L SNP,sodium nitroprusside,exogenous NO donor） was used for regulation in drought condition,and antioxidant and photosynthetic activities was determined.Three treatments were set in the experiment.[Result]SOD,CAT and APX activities of high resistance Xiamai 5 were much higher than low resistance Yumai 949,so were MDA and chlorophyll content.And the change range of these physiological indexes of high resistance species was smaller than high-yielding and low resistance species under drought stress.NO increased the adaptation to drought stress of these physiological indexes significantly.[Conclusion]Exogenous NO could increase the activity of antioxidant enzymes of wheat leaves under drought stress,and enhance the drought resistance of wheat.
