The main objective of this work is to study the effect of pre-sowing gamma irradiation and seeds soaking with ZnSO4 on germination and vegetative growth of Cleopatra mandarin and Sour orange rootstocks plants. In first part, seeds of both rootstocks were irradiated before sowing with gamma rays at 0.0, 10, 20, 40 and 80 Gray. In second one, seeds of both rootstocks were soaked before sowing in ZnSO4 solutions at 0.0, 0.05, 0.1, 0.2 and 0.4% Zn. Low gamma doses, in particular at 20 Gray, or ZnSO4 in particular at 0.2% Zn markedly promoted and accelerated germination process and stimulated plant growth of Sour orange and Cleopatra mandarin plants. Generally, it could be concluded that gamma dose at 20 Gray or Zn at 0.2% had beneficial effects on both rootstocks, however response of Sour orange to gamma rays and Zn treatments was more pronounced than Cleopatra mandarin.