Study On The Regulation Of Flavonoids Metabolism In Mulberry

Mulberry leaves are main feed of silkworms (Bombyx mori L.) and important Chinese traditional medicine. Though medicinal components of mulberry leaves are relatively complicated, Flavonoid is thought as one of the main medicinal components. Flavonoid in plant can be affected by many factors. Culture conditions of mulberry seedings such as illumination, microelement, sugar source, nitrogen, upgrowth regulator, elicitor, aromatic amino acid concentration and so on can affect synthesis of flavonoid. Glyphosate is a common herbicide of mulberry field, which is thought to affect the synthesis of aromatic amino acid and flavonoid. The effects of culturing conditions on the flavonoid content of mulberry tissue culture seedings were researched and the relationship between aromatic amino acid and the metabolism of flavonoid was discussed in this study.The optimal culture conditions for the synthesis of mulberry flavonoid obtained in the test may be helpful to the field cultivation of medicinal mulberry. The mainly results are as follows.1 The results of orthogonal test and the methods of extraction showed that the optimal methods of flavonoid extraction were as follows: The mulberry leaf powder was treated with microwave (600W) treatment for 40 second, and then extracted with 75% ethanol (liquid/solid ratio 20∶1) at temperature 80℃for 2 h. The result of extraction liquild stability test, ultraviolet spectrophotometer precision test and the standard curve test showed that coloration method of Al(NO3)3 could be used as an analysis method for determination the flavonoid content of the mulberry leaves.2 Shan sang 305 tissue culture seedings were used to investigated the effect of culture conditions on the flavonoid content of mulberry leaves. The optital medium components for flavonoid synthesis were: 30 g/L fructose, 1150 mg/L NH4NO3, 3150.2 mg/L KNO3, 11.15 mg/L MnSO4·4H2O, 4.3 mg/L ZnSO4·7H2O, 0.1 mg/L NAA (α-Naphthylacetic acid), 0.5 mg/L 6-BA (6-Benzylaminopurine) and 0.5 mg/L KT (Kinetin). The culture medium supplementied with 10 mg/L LaCl3, 0.5 mg/L SA, 10 mg/L acid hydrolyze casein or 100 mg/L Phe, was propitious for the flavonoid synthesis of mulberry leaves.3 Sha 2×Lunjiao 109 potted planting seedings were used to investigated the effect of glyphosate on the aromatic amino acid, soluble protein and flavonoid content of the mulberry leaves. The relationship between the aromatic amino acid and the the metabolism of flavonoid of mulberry were also discussed. The results showed that glyphosate could inhibite the synthesis of the aromatic amino acid (Tyr, Phe, Trp), soluble protein and flavonoid. Spraying flavonoid and aromatic amino acid could effectivly relieve the stress effects of glyphosate. The mitigative effects were better with the spraying concentrations increased and spraying times increased of aromatic amino acid or rutin.