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Asteraceae (Compositae) Stevia Stevia (Stevia rebaudiana Bertoni) is a case (Stevia), also known as Stevia, sweet grass, sweet tea. The steviol glycosides plant the whole plant is rich in sweet substances, especially leaves the highest content of the name. Stevia origin subtropical regions of South America, successfully introduced in China in 1977, more than 20 provinces and cities nationwide have cultivated in recent years, Sichuan Province stevia acreage is increasing day by day. Dry stevia leaves and branches harvested for medicinal gas fragrance, sweet taste; extract stevia as a sweetener, high sweet low heat, known as following the sugar cane, sugar beet after the world's third largest source of sugar plants have great economic value. Plant growth regulating substances gibberellin (GA) and chlormequat (CCC) has been widely used to adjust the yield and quality of plants. Gibberellin kaurene glycosides, including prior to the formation of the same main active ingredient in stevia stevioside, share the same biosynthetic pathway. Chlormequat (CCC) is a gibberellin antagonist, the chlormequat inhibited python geranyl pyrophosphate into kaurene thereby inhibiting the synthesis of gibberellin. Per plant breeding, genotyping explore, from Sichuan Province planted stevia cultivars screened four strains of certain representative; new screened four stevia strains as test material, study exogenous of spraying gibberellin and chlormequat stevia agronomic traits, physiological indicators, endogenous hormones, glycosides and yield, in order to provide a reference for stevia high yield and quality cultivation. The main findings are as follows: the 1,46 a stevia monoclonal between RA and ST glucoside content differences significant individual trees, RA glucoside content ranged from 0 to 10.56%, ST glucoside content ranged from 2.90% to 20.97%, ST RA ranged from 4.72% to 21.74%, RA / (ST RA) ranged from 0 ~ 0.758 0.242 ~ 1.000 ST / (ST RA) luffing, RA / ST ranged from 0 to 3.139; based on RA and ST glucoside content clustering results based on the classification of the phenotypic characteristics of the stevia field not consistent, stevia RA and ST glucoside, metabolic their plants, leaf shape, leaf color and other phenotypic characteristics may not be directly related to, stevia seed Determination of the breeding process monoclonal RA and ST glycoside is necessary, not simply based on the plant phenotypic characteristics preferably monoclonal. 2, four different types of stevia strains of the new filter, SR1 for high ST Stevia strains, SR2 high RA-type strains, SR3 high RC-type strains, SR5 the low RA Stevia strains as high ST. In descending order of the four strains of RA glucosinolate content SR2 gt; SR3 gt; SR1 gt; SR5, RA glucosinolate content in the highest strains SR2, RA glycoside content of 11.59 ± 0.43%, followed by SR3 content of 8.70 ± 0.12%; 4 strains ST glucosinolate content in descending order SR5 gt; SR1 gt; SR2 gt; SR3, SR5 and SR1 ST glucosinolate content of up to 17.39 ± 0.40% and 15.26 ± 0.26%, respectively; total glucosinolate content (RA ST) high to low order SR1 gt; SR2 gt; SR5 gt; SR3 SR3 strains may generate higher RC glycosides the RA ST glucosinolate content of four strains lowest. Close to the the SR2 strain SR3 strain RA / ST value, but the SR2 of RA glycosidic ST glucoside content were significantly higher than SR3 the gibberellin treatment group compared with the control group, a significant increase in plant height, long section, and the section between elongation effect mainly in the stalk the middle leaf length was significantly longer significantly narrower leaf width, leaf aspect ratio value increases; gibberellin treatments with gibberellic acid concentration increases with the increasing plant height showed leaf length, leaf width with gibberellic acid concentration decreased with increasing trend; addition SR2 strains were no significant differences remaining strains of dried leaves per plant yield is significantly lower than in the control. Leaves thicken the CCC treatment group stevia plants, leaf thickening, plant height, internode length were reduced compared with the control, but a long section, leaf length, leaf width, leaf aspect ratio, stem dry weight indicators mostly difference was not significant compared with the control; between chlormequat processing, plant height the trend grow shorter with the increasing concentration of CCC treatment; 100 mg / L and 500 mg / L chlormequat treatment will help improve SR1 production of dried leaves per plant strains, and 300 mg / L chlormequat treatment conducive SR2 strains of dried leaves per plant to increase the yield. Spraying exogenous hormones GA, especially at high concentrations stevia strains generally enhanced peroxidase enzymes activity, MDA content increased, indicating that the GA-treated stevia antioxidant capacity improve, but also shows that too high concentration of GA may some of the stress on the stevia; while spraying low concentrations of growth regulators CCC general decline of POD, CAT, SOD, MDA, and other content may be exogenous spraying on the CCC may be a certain degree of inhibition of sweet Ye Ju superoxide anion generation of oxygen free radicals. Application of GA and CCC treatment, stevia soluble sugar content of the four strains overall performance Gibberellin soluble sugar content, soluble sugar content after CCC treatment decreased or remained unchanged. In general, the of stevia changes in soluble sugar content in their total glycoside content is basically the opposite. 5, exogenous growth regulators deal with the stevia endogenous ZT content increased (except no significant impact on the SR2 strains); downward trend (except SR5 type Stevia increased IAA content) ; after CCC treatment stevia SR1 and SR3 strain performance ZT / IAA significantly with rising, SR5 strains ZT / IAA significantly with the decline, SR2 changes are not significant with; GA Apart from SR1 strains, the remaining strains change the situation with the CCC process changes similar. Generally believed ZT / IAA ratio increases, is conducive to the growth of the bud, but the trial SR1 SR3 strains ZT / IAA increased significantly, but its dry leaf yield did not improve; Endogenous ZT or content of IAA and ZT / IAA nor the corresponding association between the increase or decrease of the ratio of the content of steviol glycosides. 6, glycosides, ST SR1 strains, 100 mg / L GA and three concentrations of CCC treatment are conducive to improve its RA glucosinolate content to reduce ST glucosinolate content, improve the value of RA / ST, which GA-treated with 100 mg / L (A1) and 500 mg / L CCC processing (C3) best RA glucosinolate content, respectively, it increased to 7.29% and 8.26%, 10.3% and 25.0% compared with the control, RA / ST ratio by CK .4331 rose to 0.7678 and 0.6457; for high ST low RA SR5 Stevia strains, 100 mg / L and 300 mg / L CCC treatment to further promote the accumulation of ST glycosides inhibit RA glycosides Synthesis, improved ST / RA value, is more conducive to the separation and purification of industrial production; For high RA stevia strains SR2 and SR3, GA or CCC processing can not further improve the glucosinolate content of RA or RA / ST ratio. 7 glycoside yield, 100 mg / L CCC processing SR1 strains RA, ST, RA ST total glucosides yield increases, but consolidated RA glucosinolate content and improve the RA / ST ratio consider 500 mg / L of CCC processing (C3) is more conducive to improve sugar quality SR1 strains; For the ST low RA medicinal stevia strains SR5, 100 mg / L and 300 mg / L the CCC treatment can improve its ST glycosides production and ST / RA values, enhance its medicinal quality, and 100 mg / L of the CCC handle better; For high RA-sugar use stevia strains SR2 and SR3, different concentrations of GA or CCC processing further improve of its RA glycosides production or RA / ST ratio. In summary, stevia GA or CCC treatment response of different strains are not the same, is not conducive to the improvement of stevia dry leaf yield and glycoside content Gibberellin stevia plant becomes high, leaf narrowing Endogenous ZT content a general increase in the IAA content decreased, the high concentration stevia peroxide content in the body to increase antioxidant capacity enhancement; CCC treatment Stevia plants are robust, leaves thicken endogenous ZT The IAA content generally improved, the suitable concentration of CCC treatment will help reduce the stevia peroxide generated in vivo, and can increase its dry leaf yield and corresponding glucoside content specific concentration stevia strains vary.
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