Effects of different fertilization treatments on soil microbial functional diversity of dry tableland wheat field in south Shanxi Province.

Understanding the effects of different fertilization treatments on microbial functional diversity in loess tableland wheat soil in south Shanxi Province can provide the theoretical basis from the perspective of microbial functional diversity for chemical fertilizer reduction, wheat yield increase, and soil fertility improvement in dryland soil. We conducted a long-term field experiment with seven fertilization treatments in winter wheat cultivation area of loess tableland in south Shanxi Province, including straw charcoal fertilizer (SF), bacterial fertilizer (BF), organic fertilizer (OF), humic acid fertilizer (HF), monitoring fertilizer (MF), farmer fertilizer (FF) and no fertilizer (CK). We employed Biolog-ECO microplate technique to investigate the differences of carbon source utilization capacity and functional diversity of soil microorganisms. The results showed that all the fertilization treatments could improve the metabolic activity and functional diversity of soil microbial community. Carbon source utilization was the most efficient in SF, with the overall soil microbial utilization ability of the 31 carbon sources and the utilization ability of different guilds of carbon sources being improved. Functional diversity, richness, and dominance based on microbial carbon sources utilization were significantly higher in SF treatment than that under other five treatments, and the evenness was higher than BF. Results of principal component analysis (PCA) and biclustering heatmap analysis showed that different fertilization treatments had significant effects on the metabolic function of microbial community. SF treatment could promote the functional diversity of soil microbial community, especially for the utilization of carbohydrates, carboxylic acids and amino acids. In conclusion, straw charcoal fertilizer had positive effects on soil microbial activity in wheat soil of loess tableland in south Shanxi Province.

Molecular dynamics simulations of lipid membranes with lateral force: rupture and dynamic properties.

Membranes' response to lateral tension, and eventual rupture, remains poorly understood. In this study, pure dipalmitoylphosphatidylcholine (DPPC) lipid bilayers, under tension/pressure, were studied using molecular dynamics (MD) simulations. The irreversible membrane breakdown is demonstrated to depend on the amplitude of lateral tension, loading rate, and the size of the bilayer. In all of our simulations, -200bar lateral pressure was found to be enough to rupture lipid membrane regardless of the loading rate or the membrane size. Loading rate and membrane size had a significant impact on rupture. A variety of dynamic properties of lipid molecules, probability distribution of area per lipid particularly, have been determined, and found to be fundamental for describing membrane behavior in detail, thus providing the quantitative description for the requirement of membrane rupture.

[Differences of selenium uptake pattern of pakchoi and the possible mechanism when amended with selenate and selenite].

In order to produce selenium-enriched crops and provide a theoretical basis of phytoremediation to selenium contaminated soil, pot experiment and lab analysis were carried out to examine the differences of selenium uptake pattern and bioavailability to pakchoi (Brassica chinensis L.) when amended with selenate and selenite. Meanwhile, dynamic changes of soil available Se was analyzed to explore the reason. The results showed that no significant differences in pakchoi shoot biomass between selenate and selenite treatment were observed. The Se concentration in pakchoi decreased rapidly across time in the selenate treatments, while increased with the growing period in the selenite treatments. For the selenate treatments, the pakchoi shoot Se concentration was significantly higher than that in roots, but the opposite results were found in the selenite treatments. In the whole growth period of pakchoi, Se concentration in selenate treatment was 2-60 times higher of that in selenite treatments. The content of available Se in soil slightly decreased with the growth of pakchoi in the selenite treatments, but it decreased rapidly in the selenate treatments. The significant correlations between soil available Se and Se concentration in shoots and roots of pakchoi was found in selenate treatments, the correlation coefficients were 0.901 and 0.864, respectively. On the contrast, no significant correlation was observed between soil available Se and Se concentration of roots and shoots in selenite treatments. The results indicated that the differences between the Se uptake pattern of selenate and selenite on pakchoi were the comprehensive function of the ability of soil providing Se and crop uptake ability.