Abstract: ObjectiveRegulation effects of L-β-phenyllactic acid(LPA)on growth of wheat and its suitable concen-tration were studied to provide reference for application of LPA in wheat and other crops.MethodWheat cultivar Yang-mai 16 was used as materials.The control group was cultured in 1% MS nutrient fluid without LPA,and the treatment groups were cultured in 1% MS nutrient fluid with different concentrations of LPA(10.0,100.0 and 1000.0 mg/L).The wheat seedlings were planted by substrate culture.The plant height,root length,chlorophyll content,total soluble sugar content,soluble protein content,peroxidase(POD)activity and indoleacetic acid oxidase(IAAO)activity in leaves of the wheat seedlings were detected when the seedlings had been cultured for 7 and 14 d.ResultCompared with CK,the low concentration(10.0-100.0 mg/L)LPA had more effect on growth and physiological indicators of wheat seedlings than the high concentration(1000.0 mg/L)LPA.After treatment of suitable LPA concentrations(100.0 mg/L),on day 7 and day 14,the main physiological indicators of leaf significantly increased compared with CK(P<0.05,the same below).Among the indicators,chlorophyll content was as 29.37 and 3.57 times as that of control respectively,total soluble sugar content was as 1.50 and 2.69 times as that of control,soluble protein content was as 3.00 times and 4.33 times as that of control.IAAO activity significantly reduced by 96.64% and 95.05% and POD activity significantly reduced by 75.69% and 71.12%.ConclusionThe regulation effects of LPA on the growth of wheat seedlings are similar to that of other auxin.The low concentration LPA(10.0-100.0 mg/L)promotes growth of wheat seedlings,and the high concentration LPA (1000.0 mg/L)inhibits growth.Under this experiment condition,100 mg/L LPA achieves sound effects and can be pro-moted in wheat seedling cultivation.