The combined effects of nitrate (0, 0.1, 1, 10 mm) and salt (0, 100 mm NaCl) on nitrogen metabolism in durum wheat seedlings were investigated by analysis of nitrate reductase (NR) expression and activity, and metabolite content. High salinity (100 mm NaCl) reduced shoot growth more than root growth. The effect was independent of nitrate concentration. NR mRNA was present at a low level in both leaves and roots of plants grown in a nitrogen-free medium. NaCl increased NR mRNA at low nitrate, suggesting that chloride can mimic nitrate as a signal molecule to induce transcription in both roots and leaves. However, the level of NR protein remained low in salt-stressed plants, indicating an inhibitory effect of salt on translation of NR mRNA or an increase in protein degradation. The lower activity of nitrate reductase in leaves of high-nitrate treated plants under salinity suggested a restriction of NO transport to the shoot under salinity. Salt treatment promoted photorespiration, inhibiting carbohydrate accumulation in plants grown on low nitrate media. Under salinity free amino acids, in particular proline and asparagine, and glycine betaine could function as osmolytes to balance water potential within the cell, especially when nitrogen availability exceeded the need for growth.
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Environ Sci Technol
January 2025
Marine Synthetic Ecology Research Center, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Guangdong Provincial Observation and Research Station for Marine Ranching in Lingdingyang Bay, China-ASEAN Belt and Road Joint Laboratory on Mariculture Technology, State Key Laboratory for Biocontrol, Sun Yat-sen University, Zhuhai 519082, China.
Plants can recruit microorganisms to enhance soil arsenic (As) removal and nitrogen (N) turnover, but how microbial As methylation in the rhizosphere is affected by N biotransformation is not well understood. Here, we used acetylene reduction assay, gene amplicon, and metagenome sequencing to evaluate the influence of N biotransformation on As methylation in the rhizosphere of , a potential As hyperaccumulator. was grown in mining soils (MS) and artificial As-contaminated soils (AS) over two generations in a controlled pot experiment.
View Article and Find Full Text PDFEnviron Pollut
January 2025
Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
Nitric oxide (NO) has garnered significant attention as a critical regulatory factor and signaling molecule in plant growth. However, the effects of microplastic pollution on the release of NO by algae have not been reported. Thus, in this study, the release of NO by Skeletonema costatum and Gymnodinium sp.
View Article and Find Full Text PDFFoods
January 2025
Unit for Food Hygiene and Technology, Centre for Food Science and Veterinary Public Health, Clinical Department for Farm Animals and Food System Science, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210 Vienna, Austria.
Nitrite and nitrate in meat products may be perceived negatively by consumers. These compounds can react to form carcinogenic volatile N-nitrosamines. "Nitrite-free" (i.
View Article and Find Full Text PDFPlants (Basel)
January 2025
Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian 223300, China.
Macrolide pollution has attracted a great deal of attention because of its ecotoxic effects on microalgae, but the role of phycospheric bacteria under antibiotic stress remains unclear. This study explored the toxic effects of erythromycin (ERY) on the growth and nitrogen metabolism of ; then, it analyzed and predicted the effects of the composition and ecological function of phycospheric bacteria on microalgae under ERY stress. We found that 0.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
School of Civil Engineering and Architecture, Zhejiang University of Science and Technology, Hangzhou, Zhejiang 310023, China; Zhejiang-Singapore Joint Laboratory for Urban Renewal and Future City, Hangzhou 310023, China. Electronic address:
Despite growing attention to the environmental pollution caused by tire wear particles (TWPs), the effects of pristine and photoaged TWPs (P-TWPs and A-TWPs) and their TWP leachates (TWPLs; P-TWPL and A-TWPL) on key nitrogen removal processes in estuarine sediments remain unclear. This study explores the responses of the denitrification rate, anammox rate, and nitrous oxide (NO) accumulation to P-TWP, A-TWP, P-TWPL, and A-TWPL exposure in estuarine sediments, and assesses the potential biotoxic substances present in TWPLs. P-TWPs reduced the denitrification rate by 17.
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