| Angelica dahurica is one of genuine medicinal materials from Sichuan Provience that is commonly used in China. The lack of good varieties and high premature bolting rate in the production of cultivation may seriously affect the yield and quality of the product. Generally, selecting of fine variety as well as optimized cultural technique will be beneficial to the high quality and production of Angelica dahurica. Using molecular marker technology, we analysised the genetic diversity of this plant from various populations which mainly in Sichuan Province. Agronomic characters, yield and the contents of main bioactive constituents of Angelica dahurica were compared among different strains in various locations. We also researched the plant endogenous hormones that regulate premature bolting, which could seriously affect the yield and quality of Radix Angelicae Dahuricae. Then we selected the best of plant growth regulators which would promote the growth and improve the quality of this medical material. The growth and secondary metabolism are both influenced by phytohormone including auxin and ethylene, among which the spatial-temporal distribution and signal transduction of auxin are more interesting. Reverse genetics was used to analyze the SMALL AUXIN UP RNA (SAUR) gene in the auxin signal transduction pathway in Arabidopsis thaliana, and the molecular mechanism of this factor in the leaf growth, development and senescence was elaborated. The main results are as follows:1Genetic diversity of Angelica dahuricaaccessions analyzed by ISSRInter-simple sequence repeat (ISSR) method was applied to detect genetic variation of Angelicae dahuricae accessions from Suining of Sichuan Province. ISSR reaction system suitable to Angelicae dahuricae was optimizeded and the results of ISSR annlysis was clear and high stabilization. Fifteen primers were selected from35ISSR primers, and99DNA fragments were amplified from16samples. Of which,38fragments were polymorphic (percentage of polymorphic bands was38%. The analysis of genetic similarity showed that genetic variability among the different populations was low with genetic similarities among all accessions ranged from0.821to0.994. While the average of genetic similarity coefficient between Angelica dahurica var. formosana from Zhejiang provinceand Angelica dahurica var. formosana from Sichuan Province was larger than the data among Angelica dahurica var. formosana from Sichuan Province. The study proved that the phylogenetic relationships among populations of Angelica dahurica var. formosana from Sichuan were relatively closer. UPGMA cluster based on genetic similarity divided the16accessions into two groups, and there was some relation between the results of UPGMA and the geographical distribution of the samples. Samples from one group were all from Suining, and the other group included samples from Zhejiang, Chongqing and other areas in Sichuan.2Main agronomic traits, yield and quality of5varieties of Angelica dahurica var. formosanaUsing "chuanzhi N.ol" as the control, four A. dahurica strains bred by mixed selection method by our research group were planted in five different regions, the agronomic traits, yield and quality of the5strains were compared. The results showed that both the strains and the environment had siginificant influence on the yield and quality of A. dahurica. The selected new strains CX08-2and CX08-9were the best of them, and CX08-2is the strain selected from Nanchuan of Chongqing. The fresh weight and the dry weight of CX08-2was1773.3kg/667m2and673.2kg/667m2, increased31.1%and39.2%respectedly, compared with the control. And the chief effective component contents were up to the requirements of pharmacopeia. It was a new high-quality and high-yield strain.3Extraction, purification and synchronous determination of endogenous hormones in Angelica Dahurica with HPLCFor now, purposive cultivation is the main source for the production of A. dahurica in Sichuan Province, and the yield and quality would be reduced destructively for the high rate of premature bolting in this plant. To investigate the role of phytohormone in the process of premature bolting, a simple and rapid High Pressure Liquid Chromatography (HPLC) method for the simultaneous determination of four representative endogenous hormones Gibberellic acid (GA3), Zeatin (ZT), Indoleaceticacid (IAA) and Abscisic acid (ABA) in Angelica dahurica.is described. Endogenous hormones can be extracted using ethanolsolution (80%, V/V) under low-temperature condition. Then theextracting sample were separated by HPLC with a C18ODS column (150mm×4.6mm,5μm) using methanol-0.6%acetic acid (50:50, v/v) as mobile phase. And the signal was detected by Photodiode Array (PDA), the external standard method (ESTD) was employed for quantitative analysis. The experimental results demonstrated this method is an accurate and high-separation-efficiency technique to analyze trace amounts of the four endogenous hormones in various organs of A. dahurica.4Dynamic change of hormone during premature boltingFour endogenous hormones GA3, ZT, IAAand ABA in leaves during the premature bolting were detected using high pressure liquid chromatography (HPLC). And hormone diversities in different organs during early bolting were illuminated. The results showed that high level of GA3in leaf would prmote premature bolting, The different contents of endogenous hormones in different organs also affected premature bolting to some degree.The exogenous hormones GA and its biosynthesis inhibitor CCC were used to spray on the leaves of A. dahurica, in order to investigate the effect on the content of endogenous GA. The results showed that exogenous GA could increase the endogenous GA3content, while CCC could decrease it.5The effect of plant growth regulators onpremature blotting high-yield and good-qualityTo investigate the role of plant growth regulators on the growth and quality of A. Dahurica, five plant growth regulators:chlormequatchloride (CCC), Mepiquat chloride (PIX), Gibberellic acid (GA3), Paclobutrazol (PP333) andMaleic Hydrazide (MH) were sprayed at rosette stage. The biological traits were first measured and then imperatorin and isoimperatorin contents in its roots were detected using high pressure liquid chromatography (HPLC). The results showed that other plant growth regulators had inhibiting effects to different degree, except that higher concentration of exogenous hormones GA(100and170mg/L) could increase the premature bloting rate. Low concentration GA3can increase the yield while not influence the premature bolting rate and the coumarin content in the root of A. Dahurica.Spraying of GA3(30mg·L-1) could guarantee the growth and development of A. Dahurica to get a higher yield and maintain the active ingredients in the root.6The involvement of auxin in leaf senescence which is important for plant yield and quality SAURs, Small Auxin Up RNA genes, are early response genes to auxin, but if any of them is involved in leaf senescence is unknown. Auxin, on the other hand, has been shown to have a role in leaf senescence but if the role is positive or negative remains uncertain. Here we report the identification and characterization of an Arabidopsis leaf senescence-associated gene named SAG201. SAG201is highly up-regulated during leaf senescence and can be induced by1-naphthaleneacetic acid (NAA, a synthetic auxin species). It encodes a functionally uncharacterized SAUR that has been annotated as SAUR36. Leaf senescence in the saur36knockout lines caused by T-DNA insertion was significantly delayed as revealed by analyses of chlorophyll contents, Fv/Fm ratio (a parameter for photosystem II activities), ion leakage, and the expression of leaf senescence marker genes. These data suggest that SAUR36is a positive regulator of leaf senescence and may mediate leaf growth, which may provide guidance for the yield and quality research in medicinal plants. |
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