RESUMO
Objective: To study the effects of exogenous trehalose on the growth and total flavonoids content of licorice (Glycyrrhiza uralensis) seedlings under NaCl stress. Methods: Using licorice seedlings as the material, the effects of NaCl stress on physiological growth, enzyme activity, ion content, osmotic regulation and total flavonoid content of licorice seedlings were studied in this experiment, Microsoft Excel 2010 was used for data processing and analysis, and SPSS19.0 statistical software was used for data analysis of variance. Results: Trehalose (10-20 mmol/L) significantly reduced the damage of NaCl to licorice seedlings, and the effect was the best when the concentration of exogenous trehalose was 15 mmol/L. Under NaCl stress, when exogenous trehalose concentration was 15 mmol/L, the growth of licorice seedlings was the most exuberant and the growth amount increased the most, and the K+ and K+/Na+ concentrations that affected the osmotic regulation of licorice seedlings increased the most, while the concentrations of Na+ and Cl- were decreased compared with those without NaCl stress. When the concentration of exogenous trehalose was 15 mmol/L, the activity of antioxidant enzymes in licorice seedlings under NaCl stress could be improved, and the content of light and chlorophyll in plant cells under NaCl stress could be increased. When the concentration of exogenous trehalose was 15 mmol/L, the contents of soluble sugar, proline and cellular regulatory substance MDA in licorice seedlings under NaCl stress could be reduced. Conclusion: The application of exogenous trehalose with appropriate concentration under NaCl stress can promote the growth of licorice seedlings and the accumulation of effective components, reduce the harm of salt damage to the growth of licorice, and enhance the growth ability of Licorice under NaCl stress.
RESUMO
Objective: To explore the mitigation effect of exogenous sucrose on the root growth of licorice (Glycyrrhiza uralensis) seedlings under salt stress conditions. Methods: Licorice seedlings were taken as experimental materials, an experiment was conducted to study the effects of exogenous sucrose at different concentration on the growth and content of active ingredients, soluble sugar, proline, and activity of enzyme in licorice seedlings under NaCl stress conditions; Then to determine related indicators and analyze data by using the software SPSS 19.0. Results: This study showed that: Under salt stress conditions, after adding a certain concentration of exogenous sucrose, the relative growth rate of licorice seedlings per day was increasing, and this stress could be a significantly weakening effect, indicating that exogenous sucrose had salt stress-relieving effect. The total flavonoids and phenylalanine ammonia lyase (PAL) activity were significantly increased, the exogenous sucrose could mitigate the seedling roots under the salt stress, the licorice flavonoid content in the enhanced growth was largely, due to the activity of PAL, increased, when the concentration of exogenous sucrose was 10 mmol/L, PAL activity reaching a maximum; While the concentration of exogenous sucrose was 15 mmol/L, PAL activity turned into a downward trend, the results indicating that this mitigation had the effect depended on the concentration. After applying exogenous sucrose at different concentration, the content of licorice acid was higher than that under salt stress and reached the level without salt stress; The impact of exogenous sucrose at gradient concentration on licorice acid accumulation was not obvious. The content changes of proline and soluble sugar showed the correlation between the two. When 15 mmol/L of exogenous sucrose was applied both of them reached the controlled level; While the concentration of exogenous sucrose increasing on this basis, the contents of soluble sugar and proline in licorice seedlings were also on the rise. Compared with seedlings without salt stress treatment, the SOD and CAT activity in seedlings under the salt stress was increased; Certain concentration of exogenous sucrose could reduce the activity of SOD and CAT in seedlings under the salt stress. Conclusion: The exogenous sucrose may increase the activity of antioxidant enzymes in licorice seedlings, thereby maintaining a low level of reactive oxygen species in seedlings, and reducing the hurting degree of peroxide to cell, and improving the tolerance of licorice seedlings to the salt stress.
RESUMO
Licorice seedlings were taken as experimental materials, an experiment was conducted to study the effects of exogenous sucrose on growth and active ingredient content of licorice seedlings under NaCl stress conditions. The results of this study showed that under salt stress conditions, after adding a certain concentration of exogenous sucrose, the licorice seedlings day of relative growth rate was increasing, and this stress can be a significant weakening effect, indicating that exogenous sucrose salt stress-relieving effect. The total flavonoids and phenylalanine ammonia lyase (PAL) activity were significantly increased, the exogenous sucrose can mitigated the seedling roots under salt stress, the licorice flavonoid content in the enhanced growth was largely due to the activity of PAL an increased, when the concentration of exogenous sucrose wae 10 mmol x L(-1), PAL activity reaching a maximum, when the concentration of exogenous sucrose was 15 mmol x L(-1), PAL activity turned into a downward trend, the results indicating that this mitigation has concentration effect. After applying different concentrations of exogenous sugar, the contents of liquiritin changes with the change of flavonoids content was similar. After applying different concentrations of exogenous sucrose, the content of licorice acid under salt stress was higher than the levels were not reached during salt stress, the impact of exogenous sucrose concentration gradient of licorice acid accumulation was not obvious.