The Effects Of Environmental Factors On Secondary Metabolism Of Scrophularia Ningpoensis

Medicinal plant secondary metabolites have an important role in human life, and their contents in plants are affected by multiple ecological factors. In recent years, it is increasingly recognized by plant physiology and ecology researchers that plant secondary metabolites have a wide range of biological effects and may play an important role in the plant life and ecosystems.In cultivation process, medicinal plants are transferred from the original ecosystems into agro-ecosystems and programmed loss of biodiversity, and increased human impact. Neglecting that wild medical herbs have formatted a special metabolic pathway in a variety of biological and environmental effect, changing herbs growing environment, reducing the interaction of herbs and their habitats, long-term cultivation will make "intercommunion" capacity of the medical herbs reduce. However, secondary metabolites strength of medical herb is closely related with the "intercommunion" capacity of the plants.Radix Scrophulariaceae has an important use in cooling blood, detoxification and antimycobacterial. With the rapid development of Chinese medicine industry, Radix Scrophulariaceae is used and demanded more and more. Compared with other medicinal plants, it can be said that the research on ecological factors on the secondary metabolism of Scrophulariaceae just started. So, to explore different ecological factors on secondary metabolism of Scrophularia ningpoensis Hemsl is very important in theoretical and production. Therefore, we can only learn from other medicinal plants such as Taxus chinesis var mairei, Salvia miltiorrhiza, Bupleurum chinense and other researches. By the field investigation, and the intelligent climate incubator development, and the analysis of indoor means to plant secondary metabolism of plant physiological ecology theory and research-based disciplines to study the different ecological factors on the content of secondary metabolites in S. ningpoensis, we mainly made the following conclusions:1. From the eight regions S. ningpoensis producted in China, such as Anguo in Hebei Province, Yangling and Zhenping in Shaanxi Province, Bangdong in Hubei Province, Nanchuan in Chongqing City, Longshan in Hunan Province, Xianju and Dongyang in Zhejiang Province, the contents of the main active ingredient of Radix Scrophulariaceae, such as catalpol, aucubin, harpagide, harpagoside and cinnamic acid, were disparities. Annual precipitation and July temperature had more effect on the content of secondary metabolites of Radix Scrophulariaeciae than any other climatic factors. The effect of rainfall on plant transpiration and growth and development is more obvious than that on the photosynthesis. Within a certain range, reduced rainfall could provide a relatively more carbohydrates to S. ningpoensis plants for the secondary metabolism, so S. ningpoensis increased the levels of secondary metabolites. July is the time that S. ningpoensis transformates from vegetative growth to reproductive growth, higher temperatures promote greater consumption of carbohydrates of S. ningpoensis for reproductive growth, thereby reducing the content of secondary metabolites2. To S. ningpoensis seedlings, the drought resistances of different sources of S. ningpoensis ecotypes were quite different. The drought resistance of ecotype from Anguo, Hebei Province was the strongest, and that from Nanchuan in Chongqing City was the second, and that from Dongyang in Zhejiang Province was the worst. The mild water stress was conducive to harpagide and harpagoside accumulation, severe water stress was conducive to aucubin and catalpol accumulation, but water stress was not conducive to the accumulation of cinnamic acid. The changes in levels of secondary metabolites by water stress induced may be related to the changes in the concentration of superoxide radical.3. To flowering S. ningpoensis plants, high temperature stress damaged their photosynthetic system, and resulted their chlorophyll fluorescence decreased, so the synthesis of carbohydrates decreased. While the S. ningpoensis reproductive growth also consumed a lot of carbohydrates, it will lead to synthesis of secondary metabolites reduced on the substrate material, resulting secondary metabolites decreased. In the five compounds, harpagoside content was the most sensitive to high temperature stress. Flowering S. ningpoensis could tolerate a short period of heat stress. And the high temperature stress resistances of different sources of S. ningpoensis ecotypes were quite different. The high temperature stress resistances of the ecotype from Nanchuan in Chongqing City was the strongest, and followed by that from Dongyang in Zhejiang Province, and that from Anguo in Hebei Province was the weakest. This may relate with their long-term adaptation to local climate.4. Methyl jasmonate and salicylic acid stress both could cause superoxide anion and antioxidant enzyme activity in the leaves of S. ningpoensis changed, the former would keep on rising to superoxide anion concentration and increasing secondary metabolites such as catalpol, harpagide, aucubin and harpagoside content, while salicylic acid stress could only make short-term increase in superoxide anion concentration and no significant effect on the secondary metabolism. 5. As a plant information hormone, methyl jasmonate as an external source could induce the defensive reaction of the plant and promot of secondary metabolite content. If the fresh root and organizations of S. ningpoensis were short-term soaked in methyl jasmonate solution, the catalpol, harpagide, aucubin and harpagoside contents in them could be significantly improved. In the process of the artificial cultivation of medicinal plants, the felicitous use of plant information hormones could recovery the potential of secondary metabolites in medical plants. This will bound to be a safe, effective, stabilite way to improve quality of medicinal plants.6. The invasion by pathogenic microorganisms, usually cause plant defense response. The five different sources fungal elicitors were tested in the induction of S. ningpoensis sterile test. We found that only Dothiorella gregaria elicitor can induce secondary metabolites in S. ningpoensis increased. The further experiments showed that the Dothiorella gregaria elicitor could significantly increase secondary metabolite contents in the S. ningpoensis organization, such as catalpol aucubin, harpagide and harpagoside. The content of the four compounds induced by Dothiorella gregaria elicitor changed in different way in the experiment. They may change into each other in S. ningpoensis.