[Expression of key enzyme genes and content of saikosaponin in saikosaponin biosynthesis under drought stress in Bupleurum chinense].

To research the expression of key enzymes in saikosaponin biosynthesis and the content of saikosaponin under the drought stress, the study focused on the gene-level and the end product responses to environmental change. Taking the five months of Bupleurum chinense as research materials, the contents of saikosaponin A and saikosaponin D under different stress levels were measured by HPLC. The drought was simulated by poly ethylene glycol. The real-time fluorescence quantitative PCR was used to analyze the expression of four key enzymes genes HMGR, IPPI, FPS, ß-AS and the expression of ß-tubulin was set as a reference gene. The results showed that drought stress significantly improved the content of saikosaponin. The contents of SSa and SSd were highest researching 0.648% and 0.781%, respectively when the concentration of PEG was 10%. Meanwhile, the results reflected that the expression of four key enzymes had risen differently and FPS, ß-AS raised significantly(P<0.01). In addition, the results of correlation analysis showed that there was a significant positive correlation between the expression of the four key enzymes genes and the content of saikosaponin. In a word, the contents of secondary metabolites were regulated by the expression of key enzymes genes under the drought stress in B. chinense.

[Effect of light quality on growth, photosynthesis and effective components of Panax notoginseng].

In order to discover light quality's effects on growth, photosynthesis and effective components content of Panax notoginseng, a pot experiment using 7 light qualities (red, orange, yellow, green, cyan, violet, and blue) was conducted. The growth, photosynthesis and content change of effective components were measured during plant growth. The results showed that light qualities had significant effect on plant growth, red light increased the plant height, while cyan, yellow, violet, and blue lights promoted accumulation of biomass underground, blue and yellow lights increased the photosynthesis, cyan light increased accumulation of ginsenoside Rd, yellow and cyan lights increased total effective components of individual plant.

Suitable soil moisture contents for water use efficiency and saponins accumulation in Panax notoginseng.

Objective: The moisture content in the soil directly affects the yield and quality of Panax notoginseng, especially at the age of three years old. However, the suitable moisture for the growth of P. notoginseng is unknown. In this study, the effects of different soil moisture on the growth of P. notoginseng were studied. Methods: Four different water treatments (0.45 field capacity (FC), 0.60 FC, 0.70 FC, and 0.85 FC) were set up in Shilin County, Yunnan Province, China. The water consumption and daily dynamic of water consumption were determined daily (from April 21 to October 18, 2012), and the daily dynamic of water consumption under different weather conditions (sunny and rainy) was determined. The transpiration coefficient and water use efficiency were calculated through dry matter accumulation and total water consumption. Accumulation of saponins of roots of P. notoginseng were analyzed by HPLC after treated, and the soil moisture content suitable for the growth of P. notoginseng was estimated by regression fitting of the active ingredient accumulation and the soil moisture content. Results: The water consumption of 0.85 FC, 0.70 FC, 0.60 FC and 0.45 FC were 2.89, 3.68, 3.37 and 2.73 kg/plant per day, respectively. The water consumption of P. notoginseng from June to August was greater than other months. The daily dynamic of water consumption on sunny days and sunny days after rain showed a "double peak" feature, and it showed a "single peak" feature on rainy days. The water uses efficiency (WUE) of 0.85 FC, 0.70 FC, 0.60 FC and 0.45 FC were 2.51, 3.32, 4.59, 3.39 gDW/kg H2O, respectively. The increase of soil moisture content would reduce the WUE of P. notoginseng. With the increase of soil water content, the content of notoginsenoside R1 and ginsenoside Rg1 did not change significantly, while the content of ginsenoside Rb1 and Rd showed a decreasing trend. Conclusion: Soil moisture content significantly affected the water consumption of P. notoginseng, and when it was 56.4% of the maximum water holding capacity in the field, the sum of the four saponins of 100 strains of P. notoginseng was the highest.