[Comparative study on HPLC fingerprints between crude and processed Ligustri Lucidi Fructus].

To establish high performance liquid chromatography(HPLC) fingerprints for crude and processed Ligustri Lucidi Fructus,and to evaluate their quality through the similarity calculation and chemical pattern recognition. The separation was performed with Syncronis C_(18) column(4.6 mm × 250 mm, 5 µm), with acetonitrile(A) and 0.1% phosphoric acid solution(B) as the mobile phase for gradient elution, and a detection wavelength of 280 nm. HPLC was used to detect 22 batches of crude and processed Ligustri Lucidi Fructus,and the Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine(2012 Edition) was used to evaluate the similarity among 22 batches. The research on pattern recognition was conducted with cluster analysis(CA), principal component analysis(PCA), and partial least squares discriminate analysis(PLS-DA). HPLC fingerprints of crude and processed Ligustri Lucidi Fructus were established, with similarity ranging from 0.9 to 1.0. The crude and processed Ligustri Lucidi Fructus can be obviously distinguished by using CA, PCA and PLS-DA. According to the results of PLS-DA,11 constituents including hydroxytyrosol, tyrosol, specnuezhenide and oleuropein were the main marker components leading to the difference. The established fingerprint method is stable and reliable, and can provide method basis for quality control of crude and processed Ligustri Lucidi Fructus. Chemical pattern recognition is proved to be helpful in comprehensive quality control and evaluation of Ligustri Lucidi Fructus before and after the process.

Responses of soil nutrients and biological characteristics to nitrogen deposition in Hulun Buir Grassland, China.

Studies on effects of nitrogen deposition were mainly focused on temperate grasslands in Inner Mongolia of China. In addition, there are substantial differences between the present simulation methods and the natural nitrogen deposition. A three-year experiment was carried out to compare the effects of simulation methods (common urea and slow-released urea) and nitrogen deposition rates (0, 25, 50, 75, 100, 150, 200 and 300 kg N·hm-2·a-1) on soil nutrients and biological characteristics in Hulun Buir Grassland. We found that simulated nitrogen deposition had significant influences on soil chemical properties, biological properties and enzyme activities. With the increases of nitrogen deposition, soil pH declined with the greatest extent of 0.2 units, while the highest concentrations of total dissolved nitrogen (TDN) and dissolved organic carbon (DOC) increased by 5-7 times and 12%-36%, respectively. There was a decline trend for soil total phosphorus (TP) and organic phosphorus (TOP). Microbial biomass and metabolic activity increased firstly and then decreased. Moderate simulated nitrogen deposition rates significantly increased soil carbon, nitrogen and phosphorus related enzyme activities. Compared to common urea, using slow-released urea to simulate nitrogen deposition decelerate the decline of soil pH and the increase of dissolved nutrients, and smoothed the change of microbial biomass, metabolic activity, and nitrogen hydrolyzed enzyme activities. Overall, the results confirmed that continuous nitrogen input caused the decline of soil pH and the increase of bioavailable carbon and nitrogen, and then changed microbial biomass and activity.

[Effects of carbon and nitrogen additions on soil organic C, N, P contents and their catalyzed enzyme activities in a grassland.] / ç¢³æ°®æ·»åŠ å¯¹è‰åœ°åœŸå£¤æœ‰æœºç¢³æ°®ç£·å«é‡åŠç›¸å ³é ¶æ´»æ€§çš„å½±å“.

Soil organic C, N, P contents and their catalyzed enzyme activities play an important role in maintaining and supplying energy and nutrient in grasslands. There is no consensus on the effects of N deposition on soil organic nutrients and enzyme activities in grassland ecosystems. It remains unclear whether C addition will retard the negative effects of N deposition. We carried out an experiment in Hulun Buir grassland of Inner Mongolia to examine the effects of C and N additions on soil organic C, N, P and relative enzyme activities after three years treatments. The experiment was conducted with N treatments at five levels (0, 25, 50, 100 and 200 kg·hm-2·a-1) and with C treatments at three levels (0, 250 and 500 kg·hm-2·a-1). The results showed that higher levels of N addition significantly decreased dehydrogenase (DHA) and ß-1,4-N-acetylglucosaminidase (NAG) activities by 22.3% and 12.5%, respectively. Nitrogen addition had no significant effect on soil organic N and decreased the organic C and P contents by 6.6% and 14.5%, respectively. High C addition significantly increased DHA, ß-glucosidase (BG) activities and increased soil organic N and organic P by 15.1%, 12.2%, 1.9%, 2.6%, respectively. The results suggested that continuous N inputs inhibited microbial activities and caused losses of soil organic C and organic P. Carbon addition could enhance microbial activities and promote the secretion of enzymes and increase soil organic N and P. The combined C and N addition could play an important role in maintaining the balance and supply of soil C, N, and P in grassland ecosystem.