Germination inhibitors detected in Sapium sebiferum seeds

This study identifies endogenous inhibitors of germination associated with seed dormancy in Sapium sebiferum, Chinese tallow. Seed extracts were separated into five distinct fractions (petroleum ether, ether, ethyl acetate, methanol, and aqueous) and tested for their effect on germination of cabbage seeds. There were no significant differences in germination percentages and germination index (GI) between the solvents and the control. The five fractions differentially reduced germination percentage and GI values of cabbage seeds. According to the GI results, the greatest inhibition was with the ether fraction followed by methanol, ethyl acetate, petroleum ether, and aqueous fractions. Gas chromatography-mass spectrometry identified the constituents of the four organic fractions. Compared with the mass spectrum of the National Institute of Standards and Technology library, a compound was confirmed, provided it was more than 85% similar. Analysis of ether extracts identified four compounds: butylated hydroxytoluene (BHT; 19.7%), 1,2-benzenediol (4.1%), p-hydroxycinnamic acid, ethyl ester (2.8%), and n-hexadecanoic acid (1.4%). Fourteen, 20, and 9 compounds were identified in methanol, ethyl acetate, and petroleum ether extracts, respectively. The IC50 of BHT (the concentration at which BHT inhibits radicle growth by 50%) was 54.8 mg/L, indicating that the presence of BHT might be the primary cause of dormancy in S. sebiferum seeds.