Influence Of Environmental Factors On The Plant Metabolism Of Scutellaria Baicalensis Georgi

Objective:To understand the plant metabolism during the seed germination of Scutellaria baicalensis Georgi,we studied the temperature,light intensity,illumination time,water and macro elements,which affect the plant primary and secondary metabolism of medical material,and set basis for improving and stabilizing quality of Scutellaria baicalensis Georgi.Methods:The morphologic changes of seedlings and primary and secondary metabolites were surveyed with the knowledge of phamacentical botany, cultivation of Chinese herbal medicine,plant physiology and pharmacognosy. The elements were measured by atomic absorption spectrophotometer.The root length, root diameters were measured. The fresh weights of the roots were determined by weighing,and the content of primary metabolits was determined by UV spectrophotometer(UV),the content of secondary metabolits was determined by high performance liquid chromatography(HPLC),the activity of key enzymes were determined by UV or HPLC.Results:?The Scutellaria baicalensis Georgi seeds imbibited on the first day, radicles expoesd on the third day and two cotyledons formeded on the seventh day. The seed did not have secondary metabolites before germination. The PAL,C4H and CHS continuously increased with different stages of the seed germination.The Scutellarin, Baicalin, Wogonoside, Baicalein, Wogonin and OroxylinA produced and increased during the seed germination, and the secondary metabolites have significant negative correlation with the key enzyme. The results indicate that the soluble sugar content decreased during the first 5 days and then increased when the cotyledons formed.?The proper germination temperature is 20?25?which is proper for the seed gernmination. The activity of superoxide dismutase (SOD) , peroxidase(POD) and catalase(CAT) significantly decreased through comparion with the value under suitable temperature,the same as phenylalanine ammonia-lyase(PAL) and cinnamic acid 4-Hydroxylase(C4H). The soluble sugar content decreased with the increasing of the temperature.?The light increased the root diameter,root fresh weight,leaf area, leaf fresh weight,the soluble sugar content of the seedlings. the seedlings with full light increased he PAL,C4H and CHS activities and the content of the scutellarin, baicalin, wogonoside, baicalein, wogonin and oroxylinA.?The activation treatmeat of seed of S. baicalensis with PEG6000(15% and 20%) increased the praline, soluble sugar and soluble protein. We learned that PAL and C4H were significantly decreased under osmotic stress which is accordance to the secondary metabolites.?There were differences between the seed germination and the plant metabolism under temperature treatment. The leaf photosynthetic pigment, praline, soluble sugar, MDA and the antioxidant enzymes at the 20?and 25?were decreased than the low (10?and 15?) and high (30?and 35?) temperature. However, the PAL?C4H?CHS and the scutellarin, baicalin, wogonoside, wogonin increased, but the baicalein and oroxylinA expressed irregular.?The results showed that the water content in roots,stems and leaves, together with chlorophyll content of the leaves decreased as the water stress strengthened. Simultaneously,the specific leaf weight increased,and the content of proline and soluble sugar in Scutellaria baicalensis Georgi leaves increased significantly. The changing trends of the baicalin content in the roots, stems and leaves of Scutellaria baicalensis Georgi were different. It increased continuously in roots,while ascended constantly in the stems and leaves during the early days under water stress,but decreased sharply under heavy stress. In conclusion, praline and soluble sugar had a close correlation with the drought resistance of Scutellaria baicalensis Georgi. Moderate drought is in favor of synthesizing the secondary metabolites.?The macro elements increased the leaf chlorophyll,the soluble sugar content, the PAL, C4H, CHS activities and the secondary metabolites (K>N>P>CK).Conclusion: The plant metabolism of Scutellaria baicalensis Georgi were complex. The factors,temperature,light intensity,illumination time, water and macroelements,affected the primary and secondary metabolism,which should be controled to achieve high quality and yield according to the actual condition in production.