[Effects of elevated CO2 concentration on production and water use efficiency of spring wheat in semi-arid area.] / CO2æµ“åº¦å¢žåŠ å¯¹åŠå¹²æ—±åŒºæ˜¥å°éº¦ç”Ÿäº§å’Œæ°´åˆ†åˆ©ç”¨æ•ˆçŽ‡çš„å½±å“.

In the present study, the response of spring wheat production and water use efficiency (WUE) to the elevated CO2 concentrations was investigated based on the open-top chamber (OTC) experiment platform in Dingxi, a typical semi-arid area. Three different CO2 concentrations (390 µmol·mol-1, 480 µmol·mol-1 and 570 µmol·mol-1) were involved. The results showed that the air temperature above plant canopy increased and the soil temperature at depth of 10 cm decreased by elevated CO2. The increased CO2 concentration substantially enhanced the total and each component biomass. The aboveground dry mass under the increased CO2 concentrations (480 and 570 µmol·mol-1) was increased by 20.6% and 41.5%, respectively, and the total dry mass was increased by 19.3% and 39.6%, respectively. The biomass enhacement was mainly due to the increases of dry mass of stems and leaves, which was strongly related to the material production capacity during the middle growth stage. The root/shoot ratio under the increased CO2 concentrations (480 and 570 µmol·mol-1) was decreased by 7.3% and 11.8%, respectively, indicating that the elevated CO2 affected the dry matter accumulation of aboveground more than that of belowground. The yields of spring wheat under the increased CO2 concentrations (480 and 570 µmol·mol-1) were higher than that of the control by 8.9% and 19.9%, respectively, mainly due to the increase of grains per spike. The long-term effect of elevated CO2 concentration on the photosynthesis of spring wheat was not obvious. The photosynthetic rate significantly increased, the transpiration rate decreased and the evapotranspiration reduced with the increases of CO2 concentration. WUE at the leaf, population, and yield levels increased under elevated CO2 concentration, with the increase range of WUE being the largest at the population level and the lowest at the yield level.

[Effects of air temperature increase and precipitation change on grain yield and quality of spring wheat in semiarid area of Northwest China].

In order to predict effects of climate changing on growth, quality and grain yields of spring wheat, a field experiment was conducted to investigate the effects of air temperature increases (0 °C, 1.0 °C, 2.0° C and 3.0°) and precipitation variations (decrease 20%, unchanging and increase 20%) on grain yields, quality, diseases and insect pests of spring wheat at the Dingxi Arid Meteorology and Ecological Environment Experimental Station of the Institute of Arid Meteorology of China Meteorological Administration (35°35' N ,104°37' E). The results showed that effects of precipitation variations on kernel numbers of spring wheat were not significant when temperature increased by less than 2.0° C , but was significant when temperature increased by 3.0° C. Temperature increase enhanced kernel numbers, while temperature decrease reduced kernel numbers. The negative effect of temperature on thousand-kernel mass of spring wheat increased with increasing air temperature. The sterile spikelet of spring wheat response to air temperature was quadratic under all precipitation regimes. Compared with control ( no temperature increase), the decreases of grain yield of spring wheat when air temperature increased by 1.0°C, 2.0°C and 3.0°C under each of the three precipitation conditions (decrease 20%, no changing and increase 20%) were 12.1%, 24.7% and 42.7%, 8.4%, 15.1% and 21.8%, and 9.0%, 15.5% and 22.2%, respectively. The starch content of spring wheat decreased and the protein content increased with increasing air temperature. The number of aphids increased when air temperature increased by 2.0°C , but decreased when air temperature increased by 3.0°CT. The infection rates of rust disease increased with increasing air temperature.

[Effects of increasng field temperature on growth, development and yield of spring wheat in semi-arid area].

A field infrared temperature-increasing simulation experiment was conducted to investi- gate the effects of air temperature increases (0, 1 and 2 °C ) on growth, development and yield of spring wheat at the Dingxi Arid Meteorology and Ecological Environment Experimental Station of the Institute of Arid Meteorology of China Meteorological Administration. The results showed that the growth period of spring wheat was shortened by 7-11 d when the temperature increased by 1-2 °C. The plant height and leaf area index increased at early growth stage, decreased after entering the jointing stage, and warming 2 °C had a higher effect than warming 1 °C. Warming treatment induced an obvious decrease in chlorophyll content, especially from late grain filling stage to milk ripe stage. Compared with the control, increasing temperature by 1-2 °C decreased the spring wheat yield by 25.4%-45.5%, mainly due to obvious decreases in number of grains and grain mass per panicle. Water consumption of 0-100 cm soil horizons increased with the increase of temperature, while the variation tendency of water consumption of 100-160 cm soil horizons was not obvious.

Determination of residual clenbuterol in pork meat and liver by HPLC with electrochemical detection.

AIM: To detect the residual clenbuterol in pork meat and liver using HPLC with Coulometric electrode array system. METHODS: Homogenized meat or liver sample was treated with 1 mol x L(-1) hydrochloric acid and centrifuged, the fat existing in meat or liver tissue was removed by diethyl ether. The pH of the remaining aqueous layer was adjusted to 10.8 +/- 0.2 or 11.6 +/- 0.2 for meat or liver and liquid-liquid extraction with diethyl ether was followed. The ether extract was evaporated to dryness, the residue was dissolved in the mobile phase. The mobile phase A consisted of 50 mmol x L(-1) phosphoric acid-30 mmol x L(-1) triethylamine and was adjusted to pH 4.0 with 2 mol x L(-1) sodium hydroxide solution. The mobile phase B consisted of methanol-acetonitrile (30:45). A mixture of mobile phase A and B (80:20) was used in the method. A four electrode array module was selected for quantitation, the electrode potentials were set at 450, 600, 650 and 680 mV respectively. RESULTS: The two calibration curves for meat and liver showed good linearity between 1.88 - 60.16 ng x g(-1), the detection limit of clenbuterol was 1.2 ng x g(-1). CONCLUSION: This method using HPLC-electrochemical detection is reproducible, and the sensitivity is good enough for the determination of clenbuterol in meat and liver.