Abstract：The effect of cinnamic acid on tomato（ Lycopersicon esculentum Mill.）seed germination，
seedling growth and physiological characteristics was studied by soaking seed and root-irrigation methods. The
results showed that different cinnamic acid concentrations inhibited the tomato seed germination and seedling
growth in different degrees. The inhibition effect of low cinnamic acid concentration was weak，while its impacting
effect was strong，especially with 4.0 mmol·L-1 concentration treatment. The allelopathic effect of cinnamic acid
on tomato germination was obvious larger than on seedling growth. At the same time，cinnamic acid had negative
impact on physiological activities of tomato seedlings，especially the 4.0 mmol·L-1 concentration treatment
increased significantly the soluble sugar content in tomato leaf blades，and reduced the root activity of tomato
seedlings.
