Abstract:Three cultivars of 15 to 20-year-old litchi (Litchi chinensis Sonn.) trees grown at Zhangzhou, Fujian Province, were chosen for the experiment. Cultivar Wuye is normal in embryo development, cv. Luhebao being abortive, and cv. Lanzhu having both normal and abortive embryo development. Polymine (PAs) contents in the ovules were tested at 7, 14, 22, 31, 41 and 52 days after anthesis, i.e. from the stage of polar nuclei division to cotyledonary embryo stage, which coincided respectively with each stage of embryo development．The results showed that the contents of putrescine (Put)，spermidine (Spd) and spermine (Spm) in normal ovules were al1 higher than those in abortive ones during the whole embry ogenetic process，and reached highest level on the 7th day after anthesis，with Put content being the richest．The contents of these PAs appeared subsequently a downward tendency．However，Spm content increased slightly from the 22nd day to 31st day after anthesis (from globular to heart stages) in normal ovules．But such a phenomenon did not appear in the abortive ones．The contents of Spd and Spm evidently dropped more rapidly in the abortive ovules than those in the normal，which indicats that 1ower contents and more rapid decrease of Spd and Spm during embryogenetic process might have a close relationship with embryo abortion．The studies also showed that low ratios of (Spd+Spm)/Put and Spm/PAs might hindered embryo development．PAs contents hit the peak
before the contents of DNA and protein reached maximum，which suggests that PAs might affect embryo development by regulating the synthesis of biomacromolecules．