Grafting improves tomato yield under low nitrogen conditions by enhancing nitrogen metabolism in plants.

To alleviate the effects of increasingly severe environmental conditions and meet the increasing demand for organic agricultural products, this paper studied tomato grafting under low nitrogen conditions in an effort to enhance yield and improve fruit quality by enhancing nitrogen metabolism. In this study, we screened for two tomato genotypes, a high nitrogen use efficiency genotype ('TMS-150') and a low nitrogen use efficiency genotype ('0301111'), using rootstocks from 25 tomato genotypes and studied the effects of tomato grafting on plant yield, fruit quality, nitrogen content, activities of key nitrogen metabolism enzymes, and nitrogen use efficiency (NUE) under different nitrogen fertilizer conditions. The results showed that the yield of the tomato plants, the activities of key enzymes during nitrogen metabolism, the contents of different forms of nitrogen, and the efficiency of nitrogen use were lower at low nitrogen fertilization levels and higher at higher nitrogen fertilization levels, while the measured indicators were the highest under the N40 nitrogen fertilizer treatment. Grafting tomatoes with high-NUE tomato seedlings as the rootstock resulted in significant increases in the nitrogen content and the activity of key enzymes, enhanced the NUE of tomato plants, increased tomato yield, and improved fruit quality compared to those of the seedlings grafted with low-NUE rootstock. Our results indicate that tomato plants grafted with high-NUE rootstock presented enhanced absorption and utilization of nitrogen and increased plant yield by promoting nitrogen metabolism at different nitrogen levels.

Unitary and binary remediations by plant and microorganism on refining oil-contaminated soil.

Refining oil contaminants are complex and cause serious harm to the environment. Remediation of refining oil-contaminated soil is challenging but has significant impact in China. Two plant species Agropyron fragile (Roth) P. Candargy and Avena sativa L. and one bacterium Bacillus tequilensis ZJ01 were used to investigate their efficiency in remediating the refining oil-polluted soil sampled from an oil field in northern China. The simulated experiments of remediations by A. fragile or A. sativa alone and A. fragile or A. sativa combined with B. tequilensis ZJ01 for 39 days and by B. tequilensis ZJ01 alone for 7 days were performed in the laboratory, with B. tequilensis ZJ01 added before or after the germination of seeds. Seed germination rates and morphological characteristics of the plants, along with the varieties of oil hydrocarbons in the soil, were recorded to reflect the remediation efficiency. The results showed that the contamination was weakened in all experimental groups. A. sativa was more sensitive to the pollutants than A. fragile, and A. fragile was much more resistant to the oil hydrocarbons, especially to aromatic hydrocarbons. Adding B. tequilensis ZJ01 before the germination of seeds could restrain the plant growth while adding after the germination of A. fragile seeds notably improved the remediation efficiency. The degradation rate of oil hydrocarbons by B. tequilensis ZJ01 alone was also considerable. Together, our results suggest that the unitary remediation by B. tequilensis ZJ01 and the binary remediation by A. fragile combined with B. tequilensis ZJ01 added after the germination of seeds are recommended for future in situ remediations.

[Effects of Organic Carbon Content on the Residue and Migration of Polycyclic Aromatic Hydrocarbons in Soil Profiles].

The effects of total organic carbon content (TOC) on the migration of polycyclic aromatic hydrocarbons (PAHs) in the soil were investigated. This study analyzed the vertical properties of the concentrations and distributions of PAHs and TOC at various soil profiles from functionally different environmental regions including nature reserves, ploughs, orchards, farmlands, metropolitan areas, and industrial parks. The vertical migration properties of PAHs in soils were examined by conducting leaching experiments in soil columns. The concentrations of PAHs varied from region to region and showed strong, positive correlations with TOC in the same region. Furthermore, based on the leaching experiments, the transport abilities of PAHs were significantly influenced by TOC, although they could all be transported to the deep layers by TOC in soil columns. The downward migration of PAHs decreased with the increase in TOC and vice versa. The properties of the composition and structure of PAHs also had an obvious influence on their residues and migration in soil profiles at the same TOC conditions. In addition, the transport of PAHs was related to the amount of leaching water, the leaching time, and the additional PAHs.

[Effect of the change in sulphate and dissolved oxygen mass concentration on metal release in old cast iron distribution pipes].

To understand the processes of corrosion by-product release and the consequent "red water" problems caused by the variation of water chemical composition in drinking water distribution system, the effect of sulphate and dissolved oxygen (DO) concentration on total iron release in corroded old iron pipe sections historically transporting groundwater was investigated in laboratory using small-scale pipe section reactors. The release behaviors of some low-level metals, such as Mn, As, Cr, Cu, Zn and Ni, in the process of iron release were also monitored. The results showed that the total iron and Mn release increased significantly with the increase of sulphate concentration, and apparent red water occurred when sulphate concentration was above 400 mg x L(-1). With the increase of sulfate concentration, the effluent concentrations of As, Cr, Cu, Zn and Ni also increased obviously, however, the effluent concentrations of these metals were lower than the influent concentrations under most circumstances, which indicated that adsorption of these metals by pipe corrosion scales occurred. Increasing DO within a certain range could significantly inhibit the iron release.

[Distribution and sources of oxygen and sulfur heterocyclic aromatic compounds in surface soil of Beijing, China].

62 surface soil samples were collected from different environmental function zones in Beijing. Sulfur and oxygen heterocyclic aromatic compounds were detected by GC/MS. The objectives of this study were to identify the composition and distribution of these compounds, and discuss their sources. The results showed that the oxygen and sulfur heterocyclic aromatic compounds in the surface soils mainly contained dibenzofuran, methyl- and C2-dibenzofuran series, dibenzothiophene, methyl-, C2- and C3-dibenzothiophene series and benzonaphthothiophene series. The composition and distribution of the oxygen and sulfur heterocyclic aromatic compounds in the surface soil samples varied in the different environmental function zones, of which some factories and the urban area received oxygen and sulfur heterocyclic aromatic compounds most seriously. In Beijing, the degree of contamination by oxygen and sulfur heterocyclic aromatic compounds in the north surface soil was higher than that in the south. There were preferable linear correlations between the concentration of dibenzofuran series and fluorene series, as well as the concentration of dibenzothiophene series and dibenzofuran series. The oxygen and sulfur heterocyclic aromatic compounds in the surface soil were mainly derived from combustion products of oil and coal and direct input of mineral oil, etc. There were some variations in pollution sources of different environmental function zones.

Vertical distribution and environmental significance of PAHs in soil profiles in Beijing, China.

Vertical distribution of both the concentration and composition of polycyclic aromatic hydrocarbons (PAHs) in ten profiles in Beijing has been investigated. The results showed that PAH concentrations and compositions in topsoil from different sampling sites were different. PAH concentrations were much higher in topsoil of the investigated urban area, industrial region, and paddy field with wastewater irrigation than in other areas. Moreover, PAH concentrations in topsoil were much higher than those at greater depth, where the concentrations were relatively consistent in most soil profiles. The fingerprints of PAHs in the samples from topsoil (0-30 cm) in the same profiles were similar and were obviously different from those at greater depth, suggesting that PAH sources were consistent in topsoil samples and were discriminating between topsoil and deeper soils. PAHs in topsoil mainly arose from mixed sources of combustion of liquid fuel, coal, and/or wood, as well as wastewater irrigation, while those at greater depth were derived from soil genesis and the process of soil formation.

[Vertical distribution characteristics and composition of saturated hydrocarbon in soil profiles of Beijing].

Soil samples were collected from ten soil profiles with different environmental conditions in Beijing for saturated hydrocarbons (SHs) analysis. The vertical distribution of the both concentration and composition of SHs in ten soil profiles were investigated. Concentration of SHs in different profiles is significantly different, ranged from 1.5 microg x g(-1) to 54.1 microg x g(-1). The higher concentrations are found in the samples from B7, B9 and B10. A series of SHs including n-alkanes, isoprenoid alkanes, terpenoids and steranes, alkyl hexamethylene were detected in all samples. The order from higher content to lower in most profiles (except B7) is: n-alkanes, isoprenoid alkanes, terpenoids and steranes, alkyl hexamethylene, and the relative content of n-alkanes is obviously dominant in the upper horizons. Concentrations of SHs and content of soil organic carbon in each profile show similar trend with depth, declined rapidly down to 30 cm and trend consistent in the deep part( > 40 cm). CPI1, CPI2, (C25 + C27 + C29 + C31) / Sigma alkanes, terpenoids and steranes, and biomarker parameters suggest that pollutants are mainly from fossil fuel in B7, high plant-derived n-alkanes dominated in other profiles and fossil fuel contamination to different extent. The sources of n-alkanes in deep part of soil profiles are different from those in topsoil samples, which are related to the soil itself, such as soil parent material and process of soil formation, but the sources of alkyl hexamethylene, terpenoids and steranes between topsoil and deep part are constant.

[Modification of vascular endothelial cell treatment for patch clamp study].

A modified protocol for quick and economic treatment of cultured human umbilical vein endothelial cells has been established, which result in high viability of the cells to allow better performance in patch-clamp studies. The electrophysiological properties of Ca (2+)-activated K(+) (KCa) channel of the cultured cells were investigated with a cell-attached configuration. With this modified treatment method, the cultured cells appear fusiform in shape under microscope, and KCa channel currents could be detected readily, suggesting their eligibility for patch-clamp studies.

Characterization of TSP-bound n-alkanes and polycyclic aromatic hydrocarbons at rural and urban sites of Tianjin, China.

Total suspended particle (TSP) was collected and analyzed at rural and urban sites in Tianjin, China during the domestic heating season (from 15 November to 15 March) of 2003/4 for n-alkanes and 16 polycyclic aromatic hydrocarbons (PAHs). The normalized distribution of n-alkanes with the peak at C22, C23, C24 or C25 suggested that fossil fuel utilization was the major source of particulate n-alkanes at both sites. PAHs normalized distribution for each sample was similar and the higher molecular weight PAH dominated the profile (around 90%) indicating a stronger combustion source at both sites. Precipitation and wind were the most important meteorological factors influencing TSP and PAHs atmospheric concentrations. In the urban area the emission height had significant influence on PAHs levels at different heights under the relative stable atmospheric conditions. Coal combustion was the major source for TSP-bound PAHs at both sites based on some diagnostic ratios.