Abstract:It was found that five kinds of polyamines (putrescine, cadaverine, hexanediamme, spermidine and spermine) existed in the leaf and floral buds of pear trees during growth. But during dormancy, only three kinds of polyamines (putrescine, spermidine and spermine) could be detected. It clearly indicated the differences in changes of polyamine contents be tween the leaf and floral buds of pear trees. It,seems that cadaverine and hexanediamine were closely connected with growth and dormancy of pear buds.