[Analysis of sap flow characteristics of the Chinese pine in typical Loess Plateau Region of China].

Transpiration is one of the major processes of water consumption. It is significant for nutrients transportation, plant development, drought stress alleviation and micro-climate amelioration. In this study, the artificially planted Chinese pine (Pinus tabuliformis) was selected as an example to explore its transpiration characteristics, water-use strategies and the adaptability of the living environment in a typical loess hilly area of China. The results showed that: the sap flow rates of Chinese pine varied obviously in different seasons. The minimum sap flow rate occurred in April, followed by October, September and August, which was 0.024, 0.057, 0.062 and 0.071 mL x (cm2 x min)(-1), respectively. The rule of the diurnal variation of sap flow rate was regular, higher in daytime than at night. The flow rate was low during nighttime, but not zero. In rainfall events, the proportion of sap flow during nighttime was significantly increased, which was 3.9 times of that on sunny days, with 31.8% decrease in daytime. Chinese pine had great adaptability to unexpected climates. The variation trend of flow rate in the clod was similar to that on rainy days. The sap flow velocity was in great relevance with meteorological factors, with a declining order of solar radiation, vapor pressure deficit, relative humidity, and atmospheric temperature.

Preparation of total alkaloids from Sophora alopecuroides freeze-dried powders and investigation of its antitumor effects / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate molding technology of total alkaloids from Sophora alopecuroides freeze-dried powders and observe its inhibition effects on liver transplantation tumor in mice.</p><p><b>METHOD</b>With color, clarity, water-soluble and formability as indexes, single factor tests were adopted to screen type and amount of filler, the concentration of total alkaloids in drug liquid, pH in order to determine optimum prescription of total alkaloids from S. alopecuroides freeze-dried powders, the lowest melting point was determined and freeze drying curve was drafted. Mice hepatoma H22 ascites tumor strain was sterile inoculated in right axillary subcutaneous of mice, and antitumor effect of total alkaloids from S. alopecuroides freeze-dried powders on liver transplantation tumor H22 in mice.</p><p><b>RESULT</b>When selected 80 g x L(-1) as mannitol as filler, the concentration of total alkaloids in drug liquid was 25 g x L(-1) and pH 6.5-7.5, freeze-dried effect was optimum with fast reconstitute speed. Average inhibition rate of the big (120 mg x kg(-1)) and medium (60 mg x kg(-1)) dose group of total alkaloids from S. alopecuroides freeze-dried powders on liver transplantation tumor H22 in mice were 56.08% and 35.49%, respectively.</p><p><b>CONCLUSION</b>Preparation technology was reasonable, reproducible and stable, total alkaloids from S. alopecuroides freeze-dried powders had significant antitumor effect and showed a dose-effect relationship.</p>

[Response of sloping water erosion to rainfall and micro-earth pattern in the loess hilly area].

Severe water erosion in the key loess hilly area is affected by the coupling role of rainfall and earth surface features. In this study, rainfall simulation techniques at the micro-plot scale (1.2 m x 1.2 m; 2 m x 1.2 m) was used as the basic measures, the relations between rainfall depth, intensity and runoff-erosion under different plant morphology features as well as micro-landscape positions were quantified and analyzed. Several key findings were captured. Firstly, rainfall depth and intensity both affected water erosion significantly, while the role of the rainfall intensity was more important than that of the depth. Secondly, a strong negative correlation was found between the antecedent soil moisture content and the generation timing of surface runoff, while water erosion had a positive relation with the antecedent soil moisture. Thirdly, different plant morphology and micro-landscape positions of shrub plant (seabuckthorn) played different roles leading to different rates of surface runoff and soil erosion. Dominated by a rainfall intensity ranging from 50 to 60 mm x h(-1), runoff coefficient in those micro-plots covered by seabuckthorn was about 5%-8%, and changed into 25%, 45% and 63% in grassland-plots, bared plots covered by biological-crust and bared plots without any coverage, respectively. Fourthly, the specific landscape position of seabuckthorn in the plots was also found to play a key role in affecting water erosion processes, and seabuckthorn at the lower landscape position, rather than the upper and middle position, played a better buffering role in reducing runoff and soil loss.