The effect of nanoparticle or ionic silver on cadmium accumulation by lettuce (Lactuca sativa) was investigated. The lettuce plants were grown in Hoagland solution amended with 0, 10, 100, 1000 μg/L nanoparticle silver or 0.1, 1, 10 μg/L ionic silver. Half of the lettuce were exposed to 50 μg/L ionic cadmium. After 35 days of exposure, wet weight, dry weight, cadmium, chlorophyll and malondialdehyde of leaves and roots of the lettuces were measured. Results show that except for the 1000 μg/L nanoparticle silver which increased cadmium concentration by about 200% (p<0.001) in lettuce roots, other concentrations of nanoparticle or ionic silver do not significantly change the cadmium concentration in either leaves or roots. Biomass, chlorophyll and malondialdehyde of the lettuces are not significantly changed either. Nanoparticle silver applied as agricultural fungicide in practical amounts will not lead to increased cadmium accumulation or detectable phytotoxicity symptoms in lettuce.
Due to the combined effects of lake and Gobi, the atmospheric boundary layer located in Gobi desert regions of the Bosten Lake basin is found to possess some special regional characteristics. Based on the data of the developing meteorological observation experiments conducted in the Bosten Lake of Xinjiang Province, the height characteristics of the atmospheric boundary layer from May 21 to August 28, 2013 are analyzed. The result shows that the most prominent feature of the Gobi area of the Bosten Lake Basin is that the boundary layer often has the deep convection during the typical sunny days in the summer. The statistics also shows that in 45 days out of 100 days, the average height of the atmospheric boundary layer is above 3000 m, and the maximum height reaches 4400 m. The causes of forming the deep convective boundary layer are explored. It is argued that the atmospheric thermodynamic properties and the lake wind shear are important factors to form the deep convective boundary layer.