| 其他摘要 | 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 metabolites
2. 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. |
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