Biochar changed the distribution of imidacloprid in a plant-soil-groundwater system.

The use of biochar has increased, as its physicochemical properties reduce the adverse effects of pesticides. However, few studies have comprehensively investigated the effects of biochar on the distribution of pesticides in a plant-soil-groundwater system. In this study, a biochar produced from rice straw at 550 °C was chosen, and column experiments with five rated of biochar application (application rates = 0.0, 1.0, 2.0, 3.0, and 4.0% w/w for B0-B4, respectively) were conducted to investigate the capacity of biochar to immobilize imidacloprid (IMI) in soil, thereby decreasing its uptake by plants and leaching from soil into groundwater. Our results showed that IMI in plants, leached from soil, and detected in soil accounted for 3.78, 1.76, and 36.4% of the total IMI input, respectively, and the biochar treatments dramatically decreased the IMI distribution to 0.57, 0.11, and 13.4%, respectively. By contrast, the percentage of undetected IMI increased from 58.1% in the B0 treatment to an average of 86.0% in the biochar treatments. Biochar treatments increased IMI immobilization in soil, which could be related to the increased soil carbon content, surface area, cation exchange capacity. This study indicates that biochar with characters of high surface area and porosity can stabilize IMI and reduce its potential to harm plants and groundwater.

Soil acidification in Chinese tea plantations.

Soil acidification is a major problem in intensive agricultural systems and is becoming increasingly serious. Most research has reported the soil acidification of cereal crops, forests, and grasslands. However, there is no information about soil acidification under tea cultivation on a national scale. Therefore, we conducted a nationwide survey of soil acidification in the major tea-planting areas of China and used two nationwide surveys in three Chinese counties to evaluate changes in soil acidity over the past 20-30 years. Finally, the acidity of soil from forests and traditional and organic tea plantations was compared to evaluate the effects of agricultural management on soil acidification in tea plantations. Our results show that: (1) the average soil pH was 4.68 nationally and ranged from 3.96 to 5.48 in different provinces. Overall, 46.0% of the soil samples had a pH <4.5, which is too acidic for tea growth and only 43.9% had a soil pH of 4.5-5.5, which is optimal for tea growth. (2) In the past 20-30 years, the greatest soil acidification was observed in tea plantations; the pH decreased by 0.47 to 1.43, which is much greater than the decrease seen in fruit and vegetable systems (0.40 to 1.08) and cereals (0.30 to 0.89). (3) Compared with forests, tea cultivation with chemical fertilizer application caused serious soil acidification, while no significant acidification was observed at organic tea plantations. In conclusion, serious soil acidification occurs nationally in China, and organic management is an adaptive choice for sustainable tea growth.

Preliminary analysis of miRNA expression profile of gastric cancer tissues by microarray / 肿瘤研究与临床

Objective To analyze the expression profile of specific miRNA of gastric cancer tissues.Methods miRNA were isolated from five paired gastric cancer tissues and corresponding paracancerous normal tissues.To identify the profile of gastric cancer,miRNA hybridization and cluster analysis were processed by significance analysis of microarrays (SAM,version 2.1) and cluster software.The relative expression of hsa-miR-30c,hsa-miR-196a and hsa-miR-193b were validated by fluorescence Real-Time PCR using taqman probe.Further hsa-miR-30c taget gene was predictived by online software.Results Revealed by miRNA microarray detection,there were 16 miRNA with differential expression in gastric cancer tissues and para-cancerous normal tissues,among which HS_100,hsa-miR-27a,hsa-miR-214*,solexa-555-1991 and hsa-miR-196 were significantly up-regulated,and hsa-miR-502-3p,hsa-miR-29c*,hsa-miR-64,hsa-miR-193b,hsa-miR-551b,hsa-miR-30c,hsa-miR-582-5p,hsa-miR-625*,hsa-miR-660,hsa-miR-363 and hsa-miR-486-5p were down-regulation.The relative expression of hsa-miR-30c,hsa-miR-196a and hsa-miR-193b was in high concordance with microarray.Conclusion There is specific miRNA expression profile in gastric cancer tissues,among which differentially-expressed miRNAs may be involved in the regulation of gastric cancer progress and serve as new potential biomarkers.