The root system architecture (RSA), being a key characteristic of the root economic spectrum, describes the spatial arrangement and positioning of roots that determines the plant\'s exploration of water and nutrients in the soil. Still, it remains poorly understood how the RSA of woody plants responds to the demand for water and nutrients in different soil environments and how the uptake of these resources is optimized. Here we selected single-species plantations of Cupressus funebris and determined their topological index (TI), revised topological index (q a and q b ), root link length (RLL), root branching rate (R b and R i :R i+1), and in situ soil physicochemical properties to assess which root foraging strategies adopt in different soil environments among Guang\'an City (GA), Suining City (SN), Mianyang City (MY), and Deyang City (DY) in China. We also tested the potential effects of different nutrients upon RSA according to its plastic phenotype. Principal component analysis (PCA) showed that levels of soil nutrients were the highest at DY, followed by MY and SN, and lower at GA. A dichotomous branching pattern was observed for GA, SN, and MY, but a herringbone branching pattern for DY. The RLL was ranked as GA, > SN, > MY > DY. The R b of GA, SN, and MY was significantly lower than that of DY (p < 0.05). Among the different city regions, values of R 1 /R 2 were the largest in different regions and those of R 4 /R 5 the smallest. The cross-sectional area of the root system did not differ between any two connected branch orders. The TI, q a , and RLL were significantly and negatively correlated with soil\'s water content, porosity, total nitrogen, total potassium, available nitrogen, and available phosphorus (p < 0.05), whereas they all had significant, positive relationships with soil temperature (p < 0.05). The R b was significantly and positively correlated with total potassium in soil (p < 0.05). Redundancy analysis showed that total potassium was the main factor driving variation in RSA. Our results emphasize that the RSA is capable of corresponding plastic alterations by changing its number of internal or external links and the root link length of fine roots vis-à-vis a heterogeneous environment, thereby optimizing the rates of water capture and space utilization.

The biofilm of Bacillus cereus on the surface of X80 pipeline steel was investigated from forming to shedding. Based on the observed biofilm morphology and pit analysis, it was found that B. cereus biofilm could stimulate X80 pipeline steel pitting corrosion, which was attributed to the nitrate reduction of bacteria beneath the biofilm. Electrochemical measurements and general corrosion rate results showed that B. cereus biofilm can better accelerate X80 pipeline steel corrosion compared to sterile solutions. Interestingly, the results also showed that thick biofilms had a slight tendency to inhibit the general corrosion process compared with its formation and exfoliation, which was confirmed by scanning Kelvin probe. The corrosion rate of X80 pipeline steel in artificial Beijing soil is closely related to the state of the biofilm, and nitrate reducing bacteria accelerates the occurrence of pits. The corresponding corrosion mechanisms are proposed.

The following research describes the influence of a metallurgical ash dump on both the soil environment and the atmosphere. Soil samples were collected along a line positioned on an unprotected, hazardous ash dump and extended into the adjacent, arable land. Three soil depths were sampled at 0-20-, 20-40- and 40-60-cm depth intervals, and in each sample, pseudo-total concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, Ti, Zn, Li, Sr and V were analyzed. Additionally, emissions of CH4 and CO2 were measured at each sampling site. All emission measurements were taken in the same day, and the duration of gas measurements in each place was six minutes. The results demonstrate elevated concentrations of Cu, Cr, Pb and Zn on dump surface and along its margins, where the maximum concentrations of these elements are, respectively, 82, 23, 1144 and 8349 mg kg-1. Obtained results exceed several times both the natural background values and the values typical of local soils in the southern Poland. Moreover, natural background values for Fe, Mn, Ni, Li, Sr and V were exceeded, as well. Along the sampling line, no methane emission was detected, whereas the carbon dioxide flux varied from 7 to 42 g m-2 d-1. The reconnaissance study of the ash dump revealed a high contamination level of soils with heavy metals, which, together with the changes of soil environment, may cause migration of pollutants into the adjacent areas and, consequently, may generate hazard to the environment and, particularly, to the living organisms. Hence, further studies are necessary in order to evaluate the soil quality and the leaching of heavy metals from the dump.