Abstract: With substrate culture,this paper studied the effects of different concentrations of cinnamic acid on the physiological characteristics of Cucumis sativus seedling.The results showed that 25 μmol·L^-1 of cinnamic acid had an inhibition effect on carotenoids,but a promotion effect on chlorophyll a and b.50 μmol·L^-1 of this compound could significantly inhibit the photosynthetic rate,transpiration rate and root activity (P＜0.05),and this effect was getting stronger when the concentration was higher.150 μmol cinnamic acid·L^-1 had a significant inhibition effect on chlorophyll a and b (P＜0.05).Cinnamic acid had a weak inhibition effect on root activity when its concentration was low（25～50 μmol ·L^-1）,but the effect was significant when the concentration was high (100～150 μmol·L^-1),which became stronger with the longer handling time (P＜0.05).

Key words: Grassland landscape, Landscape pattern, Biodiversity, Landscape degradation and restoration, Landscape aesthetic value