Abstract: A walnut cuhivar ‘Liaoning 1’ was used to study the effect of exogenous polyamines on fe．male and male flower differentiation and the content of endogenous polyamines in leaves．The results in two years showed that application of Put or Spd at 1×10^-3mol·L^-1。and 1×10^-4 mol·L^-1 for two times could markedly increase the numbers of female flower and raise the ratio of floral sexuality．The content of endoge．nous Put，Spd and Spm in the mixed buds increased and had a peak at the physiological stage of female flower
buds．The content of endogenous Put in the leaves reached a peak but that of Spd and Spm changed slightly during the stage． Spraying with 1×10^-3 mol·L^-1 Put or Spd could increase the content of endogenous poly—amines in the leaves．Endogenous Put and Spd levels were affected at earlier time．while Spm at later time．

Key words: Walnut, Polyamines, Flower bud differentiation