Polyamines conjugated to deoxyribonucleic acid-protein in cell nucleus from filling grain embryos were involved in tolerance of wheat to drought.

Deoxyribonucleic acid-protein (DNAP) of the cell nucleus was purified from developing wheat (Triticum aestivum L.) embryo cells under drought stress, with two cultivars differing in drought tolerance as experimental materials - Longmai No. 079 (drought-tolerant) and Wanmai No. 52 (drought-sensitive). Levels of polyamines (PAs) non-covalently conjugated to the DNA and covalently conjugated to the proteins of DNAP were detected. After soil drought treatment for 10 days, in drought-tolerant Longmai No. 079, the increases in the levels of spermine and spermidine non-covalently conjugated to DNA of DNAP were more statistically significant (P<0.05) than in drought-sensitive Wanmai No. 52. Treatment of Wanmai No. 52 with exogenous Spm could not only enhance the tolerance of the cultivar to drought stress, as judged by flag leaf water content, plasma membrane permeability and grain growth, but also elevate the levels of spermine and spermidine noncovalently conjugated to the DNA of the cultivar. On the contrary, treatment of Longmai No. 079 with methylglyoxyl-bis guanylhydrazone, an inhibitor of S-adenosylmethionine decarboxylase, could significantly (P<0.05) aggravate the drought stress to this cultivar, accompanied by a marked decreases in the levels of spermine and spermidine non-covalently conjugated to the DNA of the cultivar. On the other hand, the content of putrescine covalently conjugated to the proteins of DNAP rose more markedly (P<0.05) in Longmai No. 079 than in Wanmai No. 52. The transglutaminase inhibitor, o-phenanthrolin, could markedly reduce the drought-induced increase in the level of putrescine covalently conjugated to the proteins of DNAP and aggravate drought stress to the two cultivars. Collectively, it could be inferred that spermine and spermidine non-covalently conjugated to the DNA and putrescine covalently conjugated to the proteins of DNAP in the developing grain embryo cell nucleus might enhance the tolerance of wheat plants to soil drought.

Relationship between polyamines conjugated to mitochondrion membrane and mitochondrion conformation from developing wheat embryos under drought stress.

The mitochondrion conformation and the contents of conjugated polyamines were investigated using the embryos of developing wheat (Triticum aestivum L.) grains of two cultivars differing in drought tolerance as experiment materials. After drought stress treatment for 7 days, the relative water content of embryo and relative increase rate of embryo dry weight of the drought-sensitive Yangmai No. 9 cv. decreased more significantly than those of the drought-tolerant Yumai No. 18 cv. Furthermore, the changes in mitochondrion conformation of Yangmai No. 9 were more marked. Meanwhile, the increases of the contents of conjugated non-covalently spermidine (CNC-Spd) and conjugated covalently putrescine (CC-Put) of Yumai No. 18 were more obvious than those of Yangmai No. 9. Treatment with exogenous Spd not only alleviated the injury of drought stress to Yangmai No. 9, but also enhanced the increase of CNC-Spd content and inhibited the change in the mitochondrion conformation of this cultivar. The treatments of Yumai No. 18 with two inhibitors, methylglyoxyl-bis (guanylhydrazone) and phenanthrolin, significantly inhibited the drought stress-induced increases of CNC-Spd and CC-Put contents of the cultivar, respectively. Meanwhile, the treatments with the two inhibitors aggravated the injury of drought stress to Yumai No. 18 and enhanced the change in the mitochondrion conformation of this cultivar. These results mentioned above suggested that the CNC-Spd and CC-Put in embryo mitochondrion membrane isolated from developing grains could enhance the wheat tolerance to drought stress by maintaining the mitochondrion conformation.

Photocatalytic abatement results from a model street canyon.

During the European Life+ project PhotoPAQ (Demonstration of Photocatalytic remediation Processes on Air Quality), photocatalytic remediation of nitrogen oxides (NOx), ozone (O3), volatile organic compounds (VOCs), and airborne particles on photocatalytic cementitious coating materials was studied in an artificial street canyon setup by comparing with a colocated nonactive reference canyon of the same dimension (5 × 5 × 53 m). Although the photocatalytic material showed reasonably high activity in laboratory studies, no significant reduction of NOx, O3, and VOCs and no impact on particle mass, size distribution, and chemical composition were observed in the field campaign. When comparing nighttime and daytime correlation plots of the two canyons, an average upper limit NOx remediation of ≤2% was derived. This result is consistent only with three recent field studies on photocatalytic NOx remediation in the urban atmosphere, whereas much higher reductions were obtained in most other field investigations. Reasons for the controversial results are discussed, and a more consistent picture of the quantitative remediation is obtained after extrapolation of the results from the various field campaigns to realistic main urban street canyon conditions.

Construction of a photocatalytic de-polluting field site in the Leopold II tunnel in Brussels.

Within the framework of the European Life+-funded project PhotoPAQ (Demonstration of Photocatalytic remediation Processes on Air Quality), which was aimed at demonstrating the effectiveness of photocatalytic coating materials on a realistic scale, a photocatalytic de-polluting field site was set up in the Leopold II tunnel in Brussels, Belgium. For that purpose, photocatalytic cementitious materials were applied on the side walls and ceiling of selected test sections inside a one-way tunnel tube. This article presents the configuration of the test sections used and the preparation and implementation of the measuring campaigns inside the Leopold II tunnel. While emphasizing on how to implement measuring campaigns under such conditions, difficulties encountered during these extensive field campaigns are presented and discussed. This included the severe de-activation observed for the investigated material under the polluted tunnel conditions, which was revealed by additional laboratory experiments on photocatalytic samples that were exposed to tunnel air. Finally, recommendations for future applications of photocatalytic building materials inside tunnels are given.

A new instrument to measure gaseous nitrous acid (HONO) in the atmosphere.

A new in situ instrument (LOPAP: long path absorption photometer) to measure gaseous nitrous acid (HONO) using wet chemical sampling and photometric detection has been developed. This instrument is aimed to overcome the known problems with current HONO measurement techniques and was designed to be a cheap, sensitive, compact, and continuouslyworking HONO monitorfor ambient air measurements in the troposphere or for measurements of higher concentrations e.g. in smog chambers, in exhaust gases, and in indoor environments. Laboratory investigations were carried outto characterize the instrument components with respect to collection efficiency, optimum dye formation, optimum detection, and interfering species. Detection limits ranging from approximately 3 to 50 pptV have been obtained with response times from 4 to 1.5 min, respectively, using different instrument parameters. The accuracy of the measurements is in the range between +/-(10-15)%. The validation of the instrument was performed in the laboratory for HONO concentrations of 3 and 30 ppbV using ion chromatography and with a DOAS (differential optical absorption spectrometer) instrument in a large outdoor smog chamber in the range from 0.1 to 20 ppbV. The deviations were well within the errors of the measurements; however, when comparing the data with the DOAS instrument systematically higher values were found with the LOPAP instrument.

Nonintrusive optical measurements of aircraft engine exhaust emissions and comparison with standard intrusive techniques.

Nonintrusive systems for the measurement on test rigs of aeroengine exhaust emissions required for engine certification (CO, NO(x), total unburned hydrocarbon, and smoke), together with CO(2) and temperature have been developed. These results have been compared with current certified intrusive measurements on an engine test. A spectroscopic database and data-analysis software has been developed to enable Fourier-transform Infrared measurement of concentrations of molecular species. CO(2), CO, and NO data showed agreement with intrusive techniques of approximately ?30%. A narrow-band spectroscopic device was used to measure CO(2) (with deviations of less than ?10% from the intrusive measurement), whereas laser-induced incandescence was used to measure particles. Future improvements to allow for the commercial use of the nonintrusive systems have been identified and the methods are applicable to any measurement of combustion emissions.