Analysis on Colonization Dynamics and Phosphate Solubilization Effects of a Penicillium Strain in Soil

【Objective】The colonization dynamics and phosphate solubilization effects of Penicillium brocae in soil were studied in order to provide references for the development and application of soil phosphate solubilization bioinoculant, .【Method】A P. brocae transformant Z3 with multiple molecular screening makers was used for soil cultivation test. Combining with the screening makers, the colony forming units (CFU) of Z3 in soil were quantified with plate counting method at different time nodes and the soil available phosphate (AP) was measured at the same time.【Result】The green fluorescent protein (gfp), hygromycin B phosphotransferase (hph) and β-glucuronidase (gus) genes could expressed normally in Z3, and there was no significant difference in the growth curve and phosphate solubilization ability between Z3 and wild type (Wt) strain. The colonization number of Z3 in soil decreased from 1×106 CFU/g to 1×105 CFU/g at the first stage, then it increased to the maximum value of 4.3×106 CFU/g at the third week and followed by a gradually decreasing to 1.4×103 CFU/g in soil at the tenth week. The soil AP content showed a trend of increasing first and then decreasing. At the sixth week, the soil AP reached the maximum value of 14.7 mg/L which increased by 41.3% compared to the AP of original soil. After inoculation for seven weeks, the soli AP gradually decreased to 12.7 mg/L at the tenth week which still increased by 22.1% compared to the AP of original soil. Additionally, it was also found that the colonization number of Z3 in soil were close to or higher than 1×105 CFU/g during the increasing of soil AP and the AP gradually decreased when the number of Z3 was significantly lower than 1×105 CFU/g.【Conclusion】The transformant Z3 can well colonize for ten weeks after being inoculated into soil, which shows good colonization ability and increases soil AP concentration significantly. Additionally, the colonization number of Z3 has a positive role in the maintenance of phosphate solubilization effects

Inhomogeneous Microstructure Evolution of 6061 Aluminum Alloyat High Rotating Speed Submerged Friction Stir Processing

An inhomogeneous microstructure induced by high rotating speed submerged friction stir processing (HRS-SFSP) on 6061 aluminum alloy was researched in detail.The microstructures of the aluminum alloy processing zone were characterized by electron backscattered diffraction (EBSD) and transmission electron microscope (TEM) qualitatively and quantitatively.The results show that the recrystallization proportion in the inhomogeneous structure of the processing zone is 14.3%, 37.8% and 35.9%, respectively. Different degrees of grain deformation can affect the dislocation and lead to the formation of a plastic–elastic interface. At the same time, the second-phase particles in the processing zone were inhomogeneity and relatively, which further promotes the plastic–elastic interface effect. The plastic–elastic interface can significantly improve the strength of aluminum alloy, whileat the same time, rely on recrystallized grains to provide enough plasticity. When the rotation speed was 3600 r/min, the strength and ductility of the aluminum alloy after HRS-SFSP were increased by 48.7% and 10.2% respectively compared with that of BM. In all, the plastic–elastic interface can be formed by using high rotating speed submerged friction stir processing, and the strength-ductility synergy of aluminum alloy can be realized at the plastic–elastic interface

Adsorption and degradation of imazapic in soils under different environmental conditions.

Imazapic is widely used in peanut production, and its residues can cause damage to succeeding crops planted in the following year. The planting area of peanut is large in Henan province. Inceptisol is the main soil type in Henan Province and was used in laboratory experiments that were conducted to investigate imazapic degradation in soil under various environmental conditions. The results indicated that the imazapic degradation rate increased with an increase in temperature, soil pH, and soil moisture, and decreased with organic matter content. The use of biogas slurry as a soil amendment accelerated imazapic degradation. The half-life of imazapic in sterilized soil (364.7 d) was longer than in unsterilized soil (138.6 d), which suggested that there was a significant microbial contribution to imazapic degradation. Imazapic adsorption was also examined and was found to be well described by the Freundlich isotherm. The results indicate that soil has a certain adsorption capacity for imazapic