ABSTRACT
To investigate the effects of Spartina alterniflora invasion on soil phosphorus(P) cycling in coastal wetlands, we selected a S. alterniflora zone(SA zone) and mudflat zone(MF zone) in the Jiaozhou Bay as the target areas for the study. The variability of total phosphorus(TP), inorganic phosphorus(IP), and their component contents in wetland soils after S. alterniflora invasion and their influencing factors was evaluated. The results showed that the average contents of TP(472.70 mg·kg-1) and IP(239.00 mg·kg-1) in the soils were significantly higher than those of TP(386.19 mg·kg-1) and IP(212.68 mg·kg-1) in the pre-invasion area, with an increase of 22.40% and 12.38%, respectively. The IP fractions in the study area were dominated by calcium-phosphorus(Ca-P) and iron-phosphorus(Fe-P), accounting for 45%-61% and 31%-49% of IP, respectively. The Ca-P content of the soil in the 10-30 cm layer decreased significantly(P<0.05) after S. alterniflora invasion, which was especially significant in July. The Fe-P content increased significantly(P<0.05); in the 0-40 cm soil layer, Fe-P was higher than that in the 40-60 cm layer(P<0.05), and showed significant enrichment in the 10-40 cm soil in July. The structural equation model showed that organic matter(OM) had a significant positive effect on TP and Fe-P after S. alterniflora invasion(P<0.01), and the normalized path coefficients were 0.775 and 0.724, respectively. Fe-P had a significant negative effect on Ca-P after invasion(P<0.01) with a normalised throughput coefficient of -0.435. The study found that S. alterniflora invasion generally increased wetland soil P content, while promoting the conversion of Ca-P to Fe-P, improving wetland P bioavailability.
Subject(s)
Phosphorus , Wetlands , Bays , Carbon/analysis , China , Introduced Species , Phosphorus/analysis , Poaceae , SoilABSTRACT
Soil organic carbon is essential for maintaining terrestrial ecosystem function and mitigating soil degradation. Soil microorganisms participate in soil carbon cycling. They are affected by tillage methods and straw returning. A split-plot design was adopted in this experiment. The whole-plot treatment had two tillage methods, subsoil tillage (ST) and rotary tillage (RT). The split-plot treatment included full straw returning (F) and no straw returning (0). The microbial community structure and carbon sequestration genes were assessed by Illumina sequencing technique. Soil organic carbon contents were measured during 2012-2017. The results showed that 1) subsoil tillage and straw returning significantly increased pH, microbial biomass carbon, total nitrogen, silt content, and clay content, while significantly decreased sand content; 2) during the test period (2012-2017), soil organic carbon (SOC) content under all treatments showed an increasing trend, but the increment for average SOC content under straw returning and subsoiling treatments was significantly higher than that of no straw returning and rotary tillage by 33.2 % and 30.6%, respectively; 3) Proteobacteria was the most abundant type of bacteria in the soil, followed by Acidobacteria and Gemmatadanetes; 4) STF treatment maintained high microbial diversity; 5) Excepted for soil sand content, soil pH, microbial biomass carbon, total nitrogen, silt content and clay content all caused the variation of soil microbial community structure under the STF treatment in the direction of SOC accumulation; 6) in addition to the gene abundance in the di- and oligosaccharides metabolic pathway, the gene abundance in the metabolic pathways for CO2 fixation, central carbohydrate metabolism, fermentation, one-carbon metabolism, organic acids, sugar alcohols and glycoside hydrolases showed that subsoil tillage was significantly higher than rotary tillage, with posi-tively correlation with soil organic carbon content. Therefore, the combination of subsoil tillage and straw returning could improve basic soil properties, affect soil microbial community structure, and increase the capacity of soil carbon fixation, thus providing a realistic basis for solving soil degradation.
Subject(s)
Agriculture , Microbiota , Soil Microbiology , Soil , Carbon/analysis , TriticumABSTRACT
In the title compound, [Sn(C(6)H(11))(3)(C(7)H(3)Br(2)O(3))], the Sn atom is four-coordinate and possesses a distorted Sn(C(3)O) tetra-hedral geometry, with Sn-C bond lengths in the range 2.132â (6)-2.144â (6)â Å and with Sn-O = 2.086â (4)â Å. The uncoordinated carboxyl-ate O atom forms a weak contact with the Sn atom, with an Snâ¯O separation of 2.962â (2)â Å.
ABSTRACT
Vibrio alginolyticus is the main Vibrio pathogen in aquaculture in the south of China. A one step loop-mediated isothermal amplification (LAMP) assay was developed for detection of Vibrio alginolyticus. A set of primers were designed from the OmpK sequence of Vibrio alginolyticus. The assay was optimised to amplify Vibrio alginolyticus DNA by incubation at 65 degrees C for only 1 h, and required only a simple water bath or heating block to provide a constant temperature of 65 degrees C. LAMP amplification products had a ladder-like appearance when electrophoresed on an agarose gel. The detection limit of the LAMP assay was n(cell) = 38/mL which was found to be higher than the commonly used PCR method. The assay was evaluated using clinical samples and the results indicated the suitability and simplicity of the test as a rapid, field diagnostic tool for Vibrio alginolyticus.
