Studies On Induced Expression Of The Enzyme Involved In Chlorophyll Degradation Of Ginkgo Biloba

Ginkgo biloba is the famous living fossil plant with high medicinal, edible and scientific value. The obvious colour change during the full is due to the degradation of chlorophyll. There is relationship between the content of chlorophyll and content of flavonoids. Therefore, the research on ginkgo chlorophyll-degrading enzyme is of great importance.This paper is mainly divided into four parts:Exogenous factors on the in vitro leaf chlorophyll degradation and on the activity of chlorophyllase(Chlase):The Ginkgo biloba was used as material and the leaf disk experiment system was adopted. The plant hormone, the carbon source, the nitrogen source as well as the metal ion was added respectively. The result indicated that the content of chlorophyll is not always in inverse proportion to the activity of Ginkgo chlorophyllase. As for the plant growth regulator (6-BA), chlorophyll content increase with the increase of the activity of chlorophyllase; As for the carbon, nitrogen, chlorophyll content decreases while the chlorophyllase activity remained at a higher level; As for the metal ion, with the degradation of chlorophyll, chlorophyllase activity also decreased.The gingko tissue culture system establishment as well as the extraneous source factor impact on chlorophyll degeneration and the enzyme activity of the seedlings:The embryos of Ginkgo biloba were used as explants for tissue culture experiment on the basic culture medium Murashige and Skoog's medium (MS) ,6,7-V medium . Regular sampling after the cotyledon expanding was used to reveal the relationship of time and chlorophyll content as well as Chlase activity. The results showed that the MS medium was better, the optimal sampling time was the 7th day .Transfering of the normal growth of seedlings to MS medium supplemented with 6-BA, the glucose, 6-BA and the glucose combination was explored to determine the Chlase activity .The results showed that the Chlase activity was effected by many factors and high concentration of ethylene can improve the Chlase activity.Extraction of gingko Chlase:Extraction of crude extracts from acetone powder of Ginkgo biloba leaves were discussed, the optimum conditions of extraction was 20 mmol/L,content 0.24%(v/v)TritonX-100 phosphate buffer(pH 7.0).The optimum extraction time was 1h.The characteristics of crude Chlase were analyzed, the reacting system was the substrate: buffer solution: enzyme solution =1:9:1,the optimum reaction contions were : temperature 37℃, pH 7.0. substrate concentration 1.6mmol/L.Extraction and purification of Gingko Chlase:Through the process of organic solvent precipitate, DEAE-ion-exchangechromatography, the polyacrylamide gel electrophoresis, SDS-PAGE, one band was obtained. The molecular weight was 27 kD.These studies will contribute to awareness of Chlase of the deciduous tree of Ginkgo biloba and lay the foundation for further study of ginkgo Chlase the reaction mechanism and applications.