Leaf chlorophyll parameters and photosynthetic characteristic variations with stand age in a typical desert species ().

As a desert shrub, combines ecological, economic, and social benefits and plays an important role in the ecological conservation of arid desert areas. Understanding its physiological characteristics and its mechanism of light energy utilization is important for the conservation and utilization of . Therefore, we selected five stands (5-, 11-, 22-, 34-, and 46-year-old) of as research objects in the study and measured their photosynthetic light response curves by a portable open photosynthesis system (Li-6400) with a red-blue light source (6400-02B).

Physiological response to salinity stress and tolerance mechanics of Populus euphratica.

The salinity stress inhibits the growth of Populus euphratica (P. euphratica), and the extent of inhibition tends to increase with a rise of salt concentration while the net photosynthesis rate, stomatal conductance, transpiration rate, and internal CO concentration are seen to decline with increasing salt concentration. Compared with the control group, the percentage decline is found to be about 48.

Spatial Variations of Soil Microbial Activities in Saline Groundwater-Irrigated Soil Ecosystem.

Spatial variations of soil microbial activities and its relationship with environmental factors are very important for estimating regional soil ecosystem function. Based on field samplings in a typical saline groundwater-irrigated region, spatial variations of soil microbial metabolic activities were investigated. Combined with groundwater quality analysis, the relationship between microbial activities and water salinity was also studied.

[Spatial heterogeneity of plant community species diversity in Ejina Oasis at the lower reaches of Heihe River].

By the method of geostatistics, this paper studied the spatial heterogeneity of plant community species diversity in Ejina Oasis at the lower reaches of Heihe River. In the study area, the Margalef richness index (Ma), Simpson diversity index (Ds), Shannon diversity index (H') and Pielou evenness index (J') were in normal distribution, and the coefficient of variation (CV) ranged from 55.8% to 67.

[Analysis of the spatial and temporal changes in soil CO2 efflux and its related factors from alpine meadow in Qilian Mountains].

Continuous field experiment was carried out on alpine meadow along different elevation gradient in Qilian Mountains during the growing season of 2004 using a soil respiration chamber (Li-6400-09) connected to a portable photosynthesis system (Li-6400). The possible effect of water-heat factors and root parameter on characteristics of alpine meadow soil respiration was statistically analyzed. The results indicate that soil CO2 efflux has apparent spatial variation laws.

[Some medical staff positive for serum SARS coronavirus antibody IgG have only mild symptoms].

Objective: To identify patients with SARS coronavirus infection who have only mild symptoms.

Method: Enzyme-linked immunosorbent assay was employed to detect serum antibody against SARS coronavirus in the lysate of whole SARS coronavirus from 19 SARS patients and 200 medical staff members without obvious SARS symptoms after possible exposure to the virus during routine medical practice.

Results: Serum IgG antibody against SARS coronavirus was detected in all the 19 SARS patients, and among the 200 staff members, 20 (10%) were found positive for the antibody but with no obvious or only mild symptoms.

[Development and application of a new hepatitis C virus genotyping method with polymerase chain reaction-reverse blot dot technique].

Objective: Using polymerase chain reaction-reverse blot dot (PCR-RDB) technique to establish a new method for hepatitis C virus (HCV) genotyping and to study the distribution of HCV genotypes in Foshan area.

Methods: HCV primers and probes were designed in 5'-untranslated region (nt-1-nt-299) of HCV. HCV RNA in serum was isolated and purified, and its cDNA was obtained by reversed transcription.

[Establishment of a new HBV genotyping method with PCR-RBD and its application].

Objective: Using PCR-RDB to establish a new method for HBV genotyping, and to survey the distribution of HBV genotypes in the Foshan area.

Methods: Biotin-labeled primers for amplification of HBV region X (nt1550-1789) were used to amplify extracted HBV DNA. HBV was genotyped by hybridization of the PCR products with immobilized specific probes (genotype A to F) on C membrane.

[Farm compost polluted water may induce pharyngo-esophageal, gastric and liver carcinoma in the chicken].

Objective: To study farm compost polluted water that may induce pharyngo-esophageal, gastric and liver carcinoma in chickens.

Methods: 280 chickens were randomized into 4 groups: experiment group 100 chickens fed with compost water + NaNO(2) by stomach tube. The other 180 were evenly randomized into 3 control groups (60 each), fed with compost water, NaNO(2) and tap water in the same way.