Recruitment and metabolomics between Canna indica and rhizosphere bacteria under Cr stress

It is of positive significance to explore the mechanism of antioxidant and metabolic response of Canna indica under Cr stress mediated by rhizosphere niche. However, the mechanisms of recruitment and interaction of rhizosphere microorganisms in plants still need to be fully understood. This study combined physiology, microbiology, and metabolomics, revealing the interaction between C. indica and rhizosphere microorganisms under Cr stress. The results showed that Cr stress increased the content of malondialdehyde (MDA) and oxygen-free radicals (ROS) in plants. At the same time, the activities of antioxidant enzymes (SOD, POD, and APX) and the contents of glutathione (GSH) and soluble sugar were increased. In addition, Cr stress decreased the α diversity index of C. indica rhizosphere bacterial community and changed its community structure. The dominant bacteria, namely, Actinobacteriota, Proteobacteria, and Chloroflexi accounted for 75.16% of the total sequence. At the same time, with the extension of stress time, the colonization amount of rhizosphere-dominant bacteria increased significantly, and the metabolites secreted by roots were associated with the formation characteristics of Proteobacteria, Actinobacteria, Bacteroidetes, and other specific bacteria. Five critical metabolic pathways were identified by metabolome analysis, involving 79 differentially expressed metabolites, which were divided into 15 categories, mainly including lipids, terpenoids, and flavonoids. In conclusion, this study revealed the recruitment and interaction response mechanism between C. indica and rhizosphere bacteria under Cr stress through multi-omics methods, providing the theoretical basis for the remediation of Cr-contaminated soil

A robust routing strategy based on deep reinforcement learning for mega satellite constellations

Abstract For mega satellite constellations, it has been a great challenge to achieve global routing and guarantee the performance of inter‐satellite transmission. To address the problem, a robust routing strategy based on deep reinforcement learning is proposed in this letter. The proposed method is applicable to degraded transmission performance, which exhibits better conformity to real‐world scenarios. Moreover, the age of information (AoI) of packets are utilized as one of the multi‐optimization targets to ensure the effectiveness of message transmission throughout the network. Numerical simulations show the outstanding average AoI performance of the proposed method and its greater robustness to jamming compared to existing methods. Meanwhile, it is also more effective for utilizing resources

Response characteristics of rhizosphere microbial community and metabolites of Iris tectorum to Cr stress

Chromium (Cr) is a toxic heavy element that interferes with plant metabolite biosynthesis and modifies the plant rhizosphere microenvironment, affecting plant growth. However, the interactions and response mechanisms between plants and rhizosphere bacteria under Cr stress still need to be fully understood. In this study, we used Iris tectorum as a research target and combined physiology, metabolomics, and microbiology to reveal the stress response mechanism of I. tectorum under heavy metal chromium stress. The results showed that Cr stress-induced oxidative stress inhibited plant growth and development and increased malondialdehyde and oxygen free radicals content. Also, it increased ascorbate peroxidase, peroxidase activity, and superoxide dismutase activity, as well as glutathione and soluble sugar content. Microbiome analysis showed that Cr stress changed the rhizosphere bacterial community diversity index by 33.56%. Proteobacteria, Actinobacteriota, and Chloroflexi together accounting for 71.21% of the total sequences. Meanwhile, the abundance of rhizosphere dominant and plant-promoting bacteria increased significantly with increasing time of Cr stress. The improvement of the soil microenvironment and the recruitment of bacteria by I. tectorum root secretions were significantly enhanced. By metabolomic analysis, five vital metabolic pathways were identified, involving 89 differentially expressed metabolites, divided into 15 major categories. In summary, a multi-omics approach was used in this study to reveal the interaction and stress response mechanisms between I. tectorum and rhizosphere bacterial communities under Cr stress, which provided theoretical basis for plant-microbial bioremediation of Cr-contaminated soils in constructed wetlands. This may provide more valuable information for wetland remediation of heavy metal pollution

Quantitative analyzing for As’s transferring process in coastal waters in Jiaozhou Bay

This paper quantified the horizontal and vertical transferring processes of As in coastal waters in the southwest and the bay mouth of Jiaozhou Bay using investigation data in July and October 1982. Results showed that the horizontal absolute loss amounts of As contents in surface waters were 0.20-2.44 μg L-1, and the horizontal relative loss amounts in surface waters were 19.23%-87.14%, respectively. The horizontal absolute loss amounts of As contents in bottom waters were 0.27-2.44 μg L-1, and the horizontal relative loss amounts in bottom waters were 25.00%-54.46%, respectively. The vertical absolute dilution amounts of As contents were 0.02-0.28 μg L-1, and the vertical relative dilution amounts were 1.78-16.66%. The vertical absolute accumulation amounts of Pb contents were 0.10-0.86 μg L-1, and the vertical relative accumulation amounts were 7.35%-35.83%. The vertical absolute dilution amount and vertical relative dilution amount of As’s contents were 0.20-0.76 μg L-1 and 19.23%-27.14%, respectively. The vertical absolute accumulation amount and vertical relative accumulation amount of As’s contents were 0.28-4.12 μg L-1 and 25.00%-91.96%, respectively. The changes of As contents in surface and bottom waters were determined by the source inputs of As and the transferring distance of As from the terrisgenous sources

A comprehensive research on petroleum hydrocarbon’s migration processes in Jiaozhou Bay

Petroleum hydrocarbon (PHC) pollution in marine bays has been more and more serous along with the rapid development of industry and economic, and understanding the migration processes in marine bays is essential to environmental protection.This paper provided a comprehensive research on the migration processes and laws in Jiaozhou Bay, Shandong Province of China using investigation data on 1984-1988. As a result, the annual changes of PHC contents, the changes of PHC’s sources and the land-ocean migration process were defined. These findings provided solid theory basis for better understanding the transporting processes and laws of pollutants in marine bay waters

The consistency of Arsenic’s high value regions in surface and bottom waters in Jiaozhou Bay

This paper analyzed the contents and distributions of As in Jiaozhou Bay in 1982. Results showed that As’s contents in bottom waters in coastal waters in the southwest of the bay and the bay mouth in Jiaozhou Bay in July and October 1982 were 0.88-4.48 μg L-1 and 0.84-1.16 μg L-1, respectively. As’s contents were much lower than the guide line of Grade I, and the pollution level of As in bottom waters in Jiaozhou Bay in 1982 was still very slight. There was high value region in coastal waters in the southwest of the bay in July 1982 (4.48 μg L-1), while in October 1982 high value region was in the bay mouth (1.16 μg L-1). The source input of As from overland runoff in the southwest was strong in July, resulted in relative high value region in surface waters in coastal waters in the southwest of the bay, and therefore resulted in high value region in bottom waters in same region by means of rapid sedimentation of As. October was wet season and there was little As input to the bay, resulted in low As’s contents in surface waters, as well as bottom waters. At any time, the terrigenous As was foremost transported to surface waters, and was subsided to sea bottom through water body by vertical water’s effect. Hence, the high value regions of As’s contents in surface and bottom waters had characteristic of consistency in Jiaozhou Bay

Quantitative analyzing for As’s transferring process in coastal waters in Jiaozhou Bay

This paper quantified the horizontal and vertical transferring processes of As in coastal waters in the southwest and the bay mouth of Jiaozhou Bay using investigation data in July and October 1982. Results showed that the horizontal absolute loss amounts of As contents in surface waters were 0.20-2.44 μg L-1, and the horizontal relative loss amounts in surface waters were 19.23%-87.14%, respectively. The horizontal absolute loss amounts of As contents in bottom waters were 0.27-2.44 μg L-1, and the horizontal relative loss amounts in bottom waters were 25.00%-54.46%, respectively. The vertical absolute dilution amounts of As contents were 0.02-0.28 μg L-1, and the vertical relative dilution amounts were 1.78-16.66%. The vertical absolute accumulation amounts of Pb contents were 0.10-0.86 μg L-1, and the vertical relative accumulation amounts were 7.35%-35.83%. The vertical absolute dilution amount and vertical relative dilution amount of As’s contents were 0.20-0.76 μg L-1 and 19.23%-27.14%, respectively. The vertical absolute accumulation amount and vertical relative accumulation amount of As’s contents were 0.28-4.12 μg L-1 and 25.00%-91.96%, respectively. The changes of As contents in surface and bottom waters were determined by the source inputs of As and the transferring distance of As from the terrisgenous sources

The consistency of Arsenic’s high value regions in surface and bottom waters in Jiaozhou Bay

This paper analyzed the contents and distributions of As in Jiaozhou Bay in 1982. Results showed that As’s contents in bottom waters in coastal waters in the southwest of the bay and the bay mouth in Jiaozhou Bay in July and October 1982 were 0.88-4.48 μg L-1 and 0.84-1.16 μg L-1, respectively. As’s contents were much lower than the guide line of Grade I, and the pollution level of As in bottom waters in Jiaozhou Bay in 1982 was still very slight. There was high value region in coastal waters in the southwest of the bay in July 1982 (4.48 μg L-1), while in October 1982 high value region was in the bay mouth (1.16 μg L-1). The source input of As from overland runoff in the southwest was strong in July, resulted in relative high value region in surface waters in coastal waters in the southwest of the bay, and therefore resulted in high value region in bottom waters in same region by means of rapid sedimentation of As. October was wet season and there was little As input to the bay, resulted in low As’s contents in surface waters, as well as bottom waters. At any time, the terrigenous As was foremost transported to surface waters, and was subsided to sea bottom through water body by vertical water’s effect. Hence, the high value regions of As’s contents in surface and bottom waters had characteristic of consistency in Jiaozhou Bay

A comprehensive research on petroleum hydrocarbon’s migration processes in Jiaozhou Bay

Petroleum hydrocarbon (PHC) pollution in marine bays has been more and more serous along with the rapid development of industry and economic, and understanding the migration processes in marine bays is essential to environmental protection.This paper provided a comprehensive research on the migration processes and laws in Jiaozhou Bay, Shandong Province of China using investigation data on 1984-1988. As a result, the annual changes of PHC contents, the changes of PHC’s sources and the land-ocean migration process were defined. These findings provided solid theory basis for better understanding the transporting processes and laws of pollutants in marine bay waters