Minimal Quark-Lepton Symmetry Model and Possible Limits on Z'-Mass from   TRISTAN and Lep200
  A minimal extension of the Standard Model containing the four-color quark-lepton symmetry is discussed. Some features of an additional $Z'$-boson originated from this symmetry are investigated and the limits on $m_{Z'}$ from the current TRISTAN data and the possible limits on $m_{Z'}$ from the future LEP200 collider are obtained. 
A.D.Smirnov