Germination Characteristics and Secondary Metabolism Regulation of Scutellaria baicalensis Georgi Seeds under Different Temperatures

[Objective] To study the germination characteristics and secondary metabolism of Scutellaria baicalensis Georgi seeds under different temperatures.[Method]The activities of superoxide dismutase(SOD)and peroxidase(POD)were determined with lactoflavine-NBT method and guaiacol-colorimetry assay,respectively.The catalase(CAT),ascorbate peroxidase(APX),phenylalanine ammonia-lyase(PAL)and cinnamic acid 4-Hydroxylase(C4H)were determined with ultraviolet spectrophotometry.The secondary metabolites were detected by High Performance Liquid Chromatography(HPLC).[Result]The germination percentage,germination potentiality and germination index were seriously affected by low or high temperature.The proper germination temperature was 20-25 ℃.The activities of SOD,POD and CAT were significantly decreased as comparison to suitable temperature.The activities of PAL and C4H were also significantly decreased as comparision to suitable temperature which was accordance to the secondary metabolites.There was a positive correlation between the flavonoids content and the PAL and C4H activity(r=0.956,r=0.951,P0.05).[Conclusion]The quality of the skullcaps could be improved by improving the activity of PAL and C4H.The proper temperature for the seed germination and the formation of secondary metabolites was 20 ℃.