Eco-Stoichiometric Characteristics of Rhizosphere and Bulk Soils of Smilax china L. along Vertical Zone Spectrum of Fanjing Mountain.

To explore the correlations between nutrients and stoichiometric characteristics in the rhizosphere and bulk soils of understory Smilax china L. in forest ecosystems at different altitudes and to clarify the rhizosphere effect of understory vegetation in forest ecosystems and its response strategy to altitude, providing a theoretical basis for better forest ecological environment protection and high-quality development in Fanjing Mountain. Understory Smilax china L. at four different altitudes were selected, with the differences and influencing factors of carbon (C), nitrogen (N), phosphorus (P) and potassium (K) mass fractions and stoichiometric ratios in their rhizosphere and bulk soils analyzed. The average mass fractions of total C, total N and alkali-hydrolyzed N in the rhizosphere and bulk soils of Smilax china L. at different altitudes were 224.43 and 181.55 g·kg-1; 9.56 and 6.81 g·kg-1; and 648.19 and 600.70 g·kg-1, respectively. The rhizosphere effect of Smilax china L. was significant at altitudes of 500 m and 1000 m but became not so prominent with the rise of altitude. The C:N ratio in the rhizosphere and bulk soils ranged from 19.51 to 39.75 and the C:P ratio ranged from 225.29 to 543.05. C accumulation is greater than N accumulation in the rhizosphere and bulk soils of Smilax china L., and both present P limitation. Based on the comprehensive analysis of the mass fractions and eco-stoichiometric ratios of soil nutrients, the P limitation in Fanjing Mountain forest ecosystem is commonly seen and should be addressed.

Fingerprint quality detection of Solanum nigrum using high-performance liquid chromatography-evaporative light scattering detection.

CONTEXT: Solanum nigrum Linn. (Solanaceae), a traditional Chinese medicine (TCM), has been used for cancer therapy. It is urgent to develop a novel quality standard to validly detect its quality. OBJECTIVE: To control its quality, a novel, accurate, and valid fingerprint method was developed by high-performance liquid chromatography-evaporative light scattering detection (HPLC-ELSD) in the current case. We could evaluate the quality of different batches and assure the stability of herbs' quality in subsequent research. MATERIALS AND METHODS: The HPLC-ELSD fingerprints have been developed through analyzing 41 batches of raw herbs collected from different areas in different harvesting time. RESULTS: We have determined the optimum extraction and detection conditions in the process of establishing herb fingerprint. And, we could establish reference fingerprint to control such herb quality. Also, we could determine optimum collecting location and harvesting time according to the fingerprint. DISCUSSION AND CONCLUSION: It is the first time a new method has been established to control the quality of S. nigrum through HPLC-ELSD. We developed combining similarity evaluation to identify and distinguish raw materials efficiently from different sources. For S. nigrum the most influenced factor on herb quality was the collecting location, and the next was the harvesting time. So, in order to get the consistent raw materials, the collecting location and the harvesting time should be fixed.