Search

Coastal silt soil (CSS), hydraulically transported and filled by dredger and mud pump from the bottom of beach in coastal zone in the process of reclamation project, has a high salinity which poses difficulties for coastal development. The use of salt-tolerant plants to improve CSS is a green and efficient method. In this process, the rhizosphere of predominate salt-tolerant plants should enrich more functional microorganisms, which will exert an indispensable ecological influence on plant growth and benign soil transformation. Therefore, comparing the characteristics of plant rhizosphere bacterial communities with different growth capacities on the same CSS can help to find the key rhizosphere hub microorganisms, which will lay a theoretical foundation for the precise improvement of CSS. High-throughput sequencing technology was used to study rhizosphere bacterial diversity of wild salt-tolerant plants (Suaeda glauca, Tripolium vulgare, and Phragmites australis) in the CSS of Lianyun New-town, Lianyungang City, China, through α-diversity, β-diversity, community composition diversity and environmental correlation analysis, and the rhizosphere bacterial functions were predicted. The results showed that the sulfur-oxidizing bacteria (Sulfurovum, Woeseia, and Thioalkalispira) which were dominant in all samples, might impart important salt-stress resistance. Bacteroidetes and sulfate-reducing bacteria Desulfuromonas were enriched in the rhizosphere of S. glauca and P. australis. Bacteroidetes can increase the degradation of organic matter, provide electrons for sulfate-reducing bacteria, and thus promote efficient sulfur-cycling. Sulfate-reducing bacteria can serve as hub bacteria for the growth of salt-tolerant plants by connecting sulfur cycles and organic matter decomposition. In addition, S. glauca, as the dominant plant in CSS, can enrich more functional dominant bacteria, and its rhizosphere bacterial community composition was significantly positively correlated with TN and TOC. These rhizosphere bacteria include phototrophic bacteria Altererythrobacter and methane-oxidizing bacteria Methylophaga related to C cycling, Geothermobacter and Pelobacter related to Fe cycling, and nitrogen-cycle-related bacteria Marinobacterium, Halomonas, and Motiliproteus involved in nitrification/denitrification. This indicates that S. glauca growth can promote the turnover of soil C, N, S, and Fe by enriching these functional bacteria. The analysis of bacterial diversity, as an important ecological indicator, can help to understand the growth of dominant plants in CSS, and the mechanism of benign soil development. The results show that the rhizosphere of S. glauca can enrich a functionally complete bacterial community, which is beneficial to the positive evolution of CSS.

Microbial-phytoremediation is an effective bioremediation technology that introduces petroleum-degrading bacteria and oil-tolerant plants into oil-contaminated soils in order to achieve effective degradation of total petroleum hydrocarbons (TPH). In this work, natural attenuation (NA), microbial remediation (MR, using Acinetobacter sp. Tust-DM21), phytoremediation (PR, using Suaeda glauca), and microbial-phytoremediation (MPR, using both species) were utilized to degrade petroleum hydrocarbons. We evaluated four different biological treatments, assessing TPH degradation rates, soil enzyme activities, and the structure of microbial community in the petroleum-contaminated soil. This finding revealed that the roots of Suaeda glauca adsorbed small amounts of polycyclic aromatic hydrocarbons, causing the structure of soil microbiota community to reshape. The abundance of petroleum-degrading bacteria and plant growth-promoting rhizobacteria (PGPR) has increased, as has microbial diversity. According to correlation research, these genera increased soil enzyme activity, boosted the number of degradation-functional genes in the petroleum hydrocarbon degradation pathway, and accelerated the dissipation and degradation of TPH in petroleum-contaminated soil. This evidence contributes to a better understanding of the mechanisms involved in the combined microbial-phytoremediation strategies for contaminated soil, specifically the interaction between microflora and plants in co-remediation and the effects on the structural reshaping of rhizosphere microbial communities., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Euhalophytes are not naturally distributed in non-saline areas. However, the reason for this is unclear. Seed germination, seedling emergence and plant tolerance to salt were evaluated in the euhalophyte Suaeda glauca. One population occurs in saline soils (SS), and another has been cultivated in non-saline soils (NSS) for more than 20 years. A total of 500 mM NaCl had a greater adverse effect on seed germination and seedling emergence of brown seeds in S. glauca from NSS compared with those from SS. The seedlings grown from brown seeds collected from NSS were uniform and dwarf, but this was not the case for the seedlings from SS. The salt tolerance of seedlings from NSS did not significantly differ from those from SS, as judged by such factors as the shoot dry weight and contents of leaf Na + and K + . The concentrations of phytohormones, such as abscisic acid, methyl jasmonate, gibberellin 3 and 4, zeatin riboside, brassinolide, indole acetic acid, and indole-3-propionic acid, in the leaves of seedlings from NSS were generally lower than those from SS under different concentrations of NaCl. In conclusion, salts are not strictly required for the growth of S. glauca. The reason why typical euhalophytes, such as S. glauca, are not found in non-saline areas is probably because the seedlings grown in NSS become dwarf and uniform, thus, weakening their ability to compete with glycophytes in non-saline habitats., Competing Interests: Declaration of competing interest We declare that there are no conflicts of interest., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Twenty-four Merino lambs were randomly assigned to four treatments: control diet (CT) consisting of 300g concentrates with ad libitum Leymus chinensis hay; C with 150g (T150), 300g (T300) and 450g (T450) Suaeda glauca seed, respectively. Meat quality, fatty acid composition of meat and lipid tissue and antioxidant status of lamb were evaluated. Inclusion of S. glauca seeds significantly increased selenium (Se) concentrations of muscle. The proportions of C18:1 trans-11 in muscle, C18:2 n-6, PUFA, n-6 series fatty acids, and the ratios of P:S in rumen contents, as well as the ratios of n-6:n-3 in adipose tissue, rumen and duodenum content have been significantly (P<0.05) improved with supplementation of S. glauca seeds to lamb diets. No significant effect was found on antioxidant status. The results suggest that S. glauca seed supplementation in lamb diets may change fatty acid composition in tissues and content of digestive tract., (Copyright © 2014 Elsevier Ltd. All rights reserved.)