[Photosynthetic physiological characteristics of Angelica dahurica var.formosana from Sichuan province in different growth years].

In this study,the leaves of autumn-sown Angelica dahurica var. formosana from Sichuan province in different growth years was used to explore the fitting model of photosynthetic response curve and the different photosynthetic physiological characteristics between annual and biennial A. dahurica var. formosana from Sichuan province. The results showed that the fitting model of the optimum light response curve of the leaves of A. dahurica var. formosana from Sichuan province with different growth years was all rectangular hyperbolic correction model. The light saturation points were 1 600,1 700 µmol·m-2·s-1,the light compensation points were17. 98,52. 23 µmol·m-2·s-1 in the leaves of annual and biennial plant,respectively. The diurnal variation curves of net photosynthetic rate,transpiration rate and stomatal conductance in the leaves all acted as a single peak value wave. The daily mean values of net photosynthetic rate and transpiration rate in the leaves of biennial plant were significantly higher than that of annual plant. There was no significant difference in daily mean stomatal conductance. The net photosynthetic rate was significantly positively correlated with stomatal conductance in both of the different growth years. The net photosynthetic rate of annual and biennial A. dahurica var. formosana from Sichuan province had extremely significant and significantly negative correlation with the intercellular CO2 respectively. The transpiration rate of annual plant was positively correlated with the effective photosynthetic radiation intensity and air temperature,but had significantly negative correlation with the intercellular CO2 concentration. The transpiration rate of biennial plant had extremely positive correlation with the effective photosynthetic radiation intensity,and negatively correlated with the intercellular CO2 concentration. In conclusion,the photosynthetic efficiency of the leaves in biennial plant of A. dahurica var. formosana from Sichuan province was higher than that in annual plant,but the ability to utilize weak light was lower than that of annual plant. It should be planted in the sunny field.

Evaluating the Memory Enhancing Effects of Angelica gigas in Mouse Models of Mild Cognitive Impairments.

(1) Background: By 2050, it is estimated that 130 million people will be diagnosed with dementia, and currently approved medicines only slow the progression. So preventive intervention is important to treat dementia. Mild cognitive impairment is a condition characterized by some deterioration in cognitive function and increased risk of progressing to dementia. Therefore, the treatment of mild cognitive impairment (MCI) is a possible way to prevent dementia. Angelica gigas reduces neuroinflammation, improves circulation, and inhibits cholinesterase, which can be effective in the prevention of Alzheimer's disease and vascular dementia and the progression of mild cognitive impairment. (2) Methods: Angelica gigas (AG) extract 1 mg/kg was administered to mildly cognitive impaired mice, models based on mild traumatic brain injury and chronic mild stress. Then, spatial, working, and object recognition and fear memory were measured. (3) Result: Angelica gigas improved spatial learning, working memory, and suppressed fear memory in the mild traumatic brain injury model. It also improved spatial learning and suppressed cued fear memory in the chronic mild stress model animals. (4) Conclusions: Angelica gigas can improve cognitive symptoms in mild cognitive impairment model mice.

[Pollen viability and stigma receptivity of Angelica dahurica from Sichuan and Hebei province].

OBJECTIVE: To provide theoretical basis for artificial cross breeding of Angelica dahurica from Sichuan and Hebei Province, the characteristics of stigma receptivity and the viability and life-span of pollen were studied. METHOD: The viability and life-span of pollen were evaluated by TTC (2, 3, 5-triphenyl tetrazlium chloride) test, and the stigma receptivity was estimated by benzidine-H2O2 method. RESULT: The pollen viability of A. dahurica from Sichuan and Hebei provinces was increased gradually since the bud stage, but those levels had since subsided after the pollen release from craze antheral. There was a little difference in the pollen viability of A. dahurica from Sichuan at different branches. While the order of the pollen viability of A. dahurica from Hebei was main stem < first-order branching < second-order branching. At room temperature, the pollen viability of both decreased during time of anthers dehiscing but also above 50% after 5 days. Compared with 4 degrees C and room temperature, conservation at - 20 degrees C could extend life of the pollen. The stigma had receptivity in 4th day and reached the highest level in the 6th day after blooming. CONCLUSION: The optimum artificial pollination times of A. dahurica was 6 days after blooming and choose the pollen in the peak stage of anthers dehiscing.

[Drought resistance of Angelica dahurica during seedling stage under polyethylene glycol (PEG-6000)-simulated drought stress].

OBJECTIVE: To study the optimum conditions of simulated drought stress, and screen the indexes of drought resistance and comprehensively assess the drought resistance of the Angelica dahurica resources during seedling stage. METHOD: Investigations were carried out on the changes of height, root length, root-shoot ration, contents of soluble sugar, proline and malondialdehyde under polyethylene glycol (PEG-6000)-simulated drought stress. A comprehensive evaluation on the drought resistance of different (varietal) species of A. dahurica during seedling stage was applied by using the method of subordinate function. And the drought resistance indexes were selected out by applying the method of grey correlative degree analysis. RESULT: Drought stress of 9 days with 20% PEG was the optimum condition for the simulation of drought stress. The results showed that the drought resistant capability decreased in the order as follows, A. dahurica from Sichuan province, A. dahurica from Henan province, A. dahurica from Hebei province and A. dahurica from Zhejiang province. And the order of correlative degree of drought resistance and indexes was: soluble sugar > root length > proline > root-shoot ration > total content of chlorophyll > chlorophyll b > chlorophyll a > height > malondialdehyde. CONCLUSION: Osmotic adjustment substance and the indexes related to the root have more influence on the drought resistance of A. dahurica during seedling stage. A. dahurica from Sichuan province shows the highest drought resistance during seedling stage.