摘要:
Several mechanisms have been proposed to explain NH4+ toxicity. However, the core information about the biochemical regulation of plants in response to NH4+ toxicity is still lacking. In this study, the tissue NH4+ concentration is an important factor contributing to variations in plant growth even under nitrate nutrition and NH4+ tolerance under ammonium nutrition. Furthermore, NH4+ led to the reprogramming of the transcriptional profile, as genes related to trehalose-6-phosphate and zeatin biosynthesis were downregulated, whereas genes related to nitrogen metabolism, camalexin, stilbenoid and phenylpropanoid biosynthesis were upregulated. Further analysis revealed that a large number of genes, which enriched in phenylpropanoid and stilbenoid biosynthesis, were uniquely upregulated in the NH4+- tolerant ecotype Or-1. These results suggested that the NH4+-tolerant ecotype showed a more intense response to NH4+ by activating defense processes and pathways. Importantly, the tolerant ecotype had a higher (NH4+)-N-15 uptake and nitrogen utilization efficiency, but lower NH4+, indicating the tolerant ecotype maintained a low NH4+ level, mainly by promoting NH4+ assimilation rather than inhibiting NH4+ uptake. The carbon and nitrogen metabolism analysis revealed that the tolerant ecotype had a stronger carbon skeleton production capacity with higher levels of hexokinase, pyruvate kinase, and glutamate dehydrogenase activity to assimilate free NH4+, Taken together, the results revealed the core mechanisms utilized by plants in response to NH4+, which are consequently of ecological and agricultural importance.
关键词:
energy sorghum;phytoremediation;Cd;regeneration cropping system
摘要:
Planting energy sorghum to remove soil cadmium (Cd) has been selected as an effective phytoremediation method in subtropical farmland in China in recent years. Nevertheless, the effects of energy sorghum species and cropping systems on Cd removal by energy sorghum are still not fully understood. In the present work, biomass sorghum (BS) and sweet sorghum (SS) were planted for screening varieties and comparing the applicability of cropping systems to remove Cd from contaminated soils through batch field experiments. The results indicated that BS had a higher plant height (4.70–75.63%), lower water content in the shoot (4.78–13.49%), greater dry biomass yield (13.21–125.16%), and stronger Cd removal (average 45.71%) compared with SS. Significant differences (p < 0.05) were observed in the agronomic traits and Cd accumulation of energy sorghums with genetic regulation of varieties. Pearson correlation coefficients analysis and the structural equation model (SEM) showed that plant height was the crucial agronomic parameter affecting the dry biomass yield, and Cd concentration in the stem was the key factor for evaluating the Cd extraction ability of energy sorghums, which indirectly determined the removal of Cd by energy sorghum together. Furthermore, the regeneration cropping system was the most suitable because of the adaptation to climatic conditions of energy sorghums in subtropical regions of China, and its Cd removal efficiency increased by more than 49% compared with double cropping and single cropping systems, respectively. Our study provides valuable information for the phytoremediation of Cd-contaminated soil in Chinese subtropical farmland.
摘要:
Long-term consumption of tea with high fluoride (F) content has a potential threat to human health. The application of different amounts of biochar to reduce F accumulation in tea leaves has been little studied. In this study, a pot experiment was conducted to investigate the effect of biochar amounts (0, 0.5%, 2.5%, 5.0%, 8.0%, and 10.0%, w/w) on tea F content during the tea plant growth. Changes in tea quality, soil F fraction, and soil properties caused by biochar and the relationship with tea F accumulation were also considered. The results showed that the application of biochar amendment significantly reduced water-soluble F contents in tea leaves compared to CK (without biochar), especially in the 8.0% treatment (72.55%). Overall, biochar contributed to improving tea polyphenols and caffeine, but had no significant impact on free amino acids and water leachate. Compared with CK, 5.0-10.0% biochar significantly increased soil water-soluble F content due to the substitution of F- with OH- under high pH. Additionally, biochar applied to tea garden soil was effective in decreasing the soil exchangeable aluminum (Ex-Al) content (46.37-91.90%) and increasing the soil exchangeable calcium (Ca2+) content (12.02-129.74%) compared to CK, and correlation analysis showed that this may help reduce F enrichment of tea leaves. In general, the application of 5.0-8.0% biochar can be suggested as an optimal application dose to decrease tea F contents while simultaneously improving tea quality.
摘要:
BACKGROUND: A growing number of researches indicated the association between plasma trace elements and blood lipids. However, the potential interaction and dose-response relationship were less frequently reported. METHODS: In this study, a total of 3548 participants were recruited from four counties in Hunan Province, South China. Demographic characteristics were collected by face-to-face interviews and inductively coupled plasma mass spectrometry (ICPMS) was used to determine the levels of 23 trace elements in plasma. We applied a fully adjusted generalized linear regression model (GLM) and a multivariate restricted cubic spline (RCS) to estimate the correlation, dose-response relationship and possible interaction between 23 trace elements and four blood lipid markers. RESULTS: The results indicated positive dose-response relationships of plasma (66)zinc with triglycerides (TG) and low density lipoprotein cholesterol (LDL-C), plasma (78)selenium with LDL-C and total cholesterol (TCH), and plasma (59)cobalt with high-density lipoprotein cholesterol (HDL-C). There was a negative dose-response relationship between (59)cobalt and LDL-C. Further analysis found that (66)zinc and (59)cobalt had an antagonistic effect on the risk of increased LDL-C level. CONCLUSIONS: This study added new evidence for the potential adverse effects of (66)Zn and (78)Se on blood lipids, and provided new insight into the threshold value setting for metals as well as the intervention strategy for dyslipidemia.
摘要:
This review aims to provide a holistic synopsis of the current state of the art knowledge on caproic acid pro-duction via anaerobic fermentation from the perspectives of microbes and metabolic pathway. The pure bacterial isolations with ability of caproic acid synthesis were summarized for metabolic identification and syntrophic potentials. Compared with single bacterium, mixed microflora with caproic acid production capacity is more conducive to caproic acid recovery and stability of the fermentation system. The anaerobic fermentation influ-encing factors, such as pH, temperature, electron donor and acceptor, hydrogen partial pressure, and competition between microbes were discussed. It is found that these factors essentially affect the performance of microbes causing system fluctuation thus decreased caproic acid production. Facing with the immature caproic acid separation technology, were compared from the prospect of application and electrodialysis was proposed as the mainstream technology in future. Simultaneously, it is believed that in-situ separation strategy can improve the yield and purity of caproic acid. Targeting on a large scale caproic acid production through anaerobic fermen-tation, it is also necessary to strengthen the research on the synergy and competition between microbes in the process of anaerobic fermentation, and to establish a readiness caproic acid separation technology. This work is expected to contribute to the goal of carbon summit and carbon neutrality.
摘要:
Sulfate affects the transformation of arsenic (As) in soil and its absorption by plant roots. However, the influence of sulfate and irrigation interactions on the mobility of As in the soil-rice system remains poorly understood. To address this gap, we conducted a pot experiment with varying sulfate levels and irrigation modes to examine their effects on rice As translocation, soil As forms, iron plaque formation, and microorganisms involved in As transformation. The addition of exogenous sulfate significantly reduced grain As levels by a maximum of 60.1%, 46.7%, and 70.5% under flooding (F), flooding-moist alternate (FM), moist (M) conditions, respectively. However, the changes in soil available As did not fully correspond to grains As content. Soil available As was only reduced by sulfate under the FM treatment, which limited grains As accumulation under this condition. The reduction in grains As content under F and M conditions was mainly attributed to sulfate-induced increases in soil pH, which in turn inhibited As translocation and promoted iron plaque formation. Additionally, both irrigation mode and sulfate fertilization independently or interactively influenced the abundance of Sulfuritalea, Koribacter, Geobacter, and Sulfuriferula, thereby affecting the As forms in soil through the Fe/S redox process. Specifically, under F and FM conditions, SO(4)(2-)-S inhibited Geobacter but stimulated Fe-oxidizing bacteria, possibly resulting in increased As bound to Fe/Mn oxides (As-F3). Under M condition, SO(4)(2-)-S levels regulated As adsorption and release through the participation of Fe/S cycle bacteria, specifically influencing the adsorbed As fraction (As-F2). Therefore, the addition of SO(4)(2-)-S hindered As translocation to grains by promoting As sequestration in the iron plaque and facilitating microbe-mediated As immobilization through the Fe/S cycle, which was dependent on soil moisture. These results can be used as a guide for sulfur fertilizer application under different soil moisture with the goal of minimizing rice grain As.
关键词:
Paddy soil;Type I and II methanotrophs;Methane oxidation rate;Carbon conversion efficiency;PLFA-SIP;Climate zones;Soil pH
摘要:
Conventional aerobic methanotrophs oxidize methane (CH4) and covert CH4-derived carbon (C) into biomass at the oxic-anoxic interface of inundated rice paddy fields, playing indispensable role in mitigating greenhouse gas emissions and loss of organic C from methanogenesis. Two phylogenetically distinct groups of methanotrophs, type I (gamma-proteobacteria) and type II (alpha-proteobacteria) methanotrophs, often co-exist in rice paddy soil and compete for CH4 biotransformation. Since these two methanotrophic groups also possess differential kinetics of CH4 oxidation and pathways of C assimilation, the consequence of their niche differentiation and metabolic differences in soil is expected to affect the CH4 oxidation rate and C conversion efficiency. Here, we examined the microbiology, chemistry, and CH4 metabolism in 24 geographically different paddy soils, covering four climate zones of eastern China. High-throughput sequencing of pmoA gene displayed a clear separation of in situ methanotrophic compositions between temperate (warm and mid-temperate) and warmer (subtropics and tropics) climate zones, likely driven by soil pH. Both methanotrophic groups were detected in soils but proportions of type I methanotrophs increased in temperate soils of higher pH (accounting for 76.1 +/- 12.4% and 44.1 +/- 14.8% in warm temperate and mid-temperate, respectively). Type II methanotrophs prevailed in warmer zones (accounting for 66.2 +/- 21.6% and 70.5 +/- 12.1% in tropics and subtropics, respectively) where soils were more acidic. Higher incorporation of 13C for synthesis in C14+C16 PLFAs (63.1-93.4% of total production of 13C-PLFAs) was found based on microcosm incubation, reflecting type I methanotrophs dominated the CH4 assimilation in paddy soils. Particularly, temperate soils with increased proportions of type I methanotrophs showed higher CH4 oxidation rate and C conversion efficiency. Collectively, this study depicts a continental-scale disparity of methanotrophic dynamics that tightly associates with consequence of niche differentiation of different types of methanotrophs and highlights the importance of microbiological control to maximize the rate and efficiency of methanotrophy.
摘要:
With the development of nanotechnology, nano-pesticides have been developed and show better application effects than traditional pesticides, which have a good development prospect. Copper hydroxide nanoparticles (Cu(OH)(2) NPs) are one of the specific fungicides. However, there is still no reliable method to evaluate their environmental processes, which is essential for the broad application of new pesticides. Since soil is a vital link between pesticides and crops, this study took linear and slightly soluble Cu(OH)(2) NPs as the research object and established a method to quantitatively extract Cu(OH)(2) NPs from the soil. Five essential parameters in the extraction process were optimized first, and then the extraction effect of this optimal method was further tested under different nanoparticles and soil conditions. The optimal extraction method was determined, including (i) Dispersant: 0.2% carboxymethyl cellulose (CMC) with a molecular weight of 250,000; (ii) Mixing conditions of soil and dispersant: water bath shaking for 30min, water bath ultrasonication for 10min (energy of the ultrasonication=6kJ/ml); (iii) Phase separation conditions: settlement for 60min; (iv) Solid-to-liquid ratio: 1:20; (v) 1 extraction cycle. After optimization, 81.5% of the supernatant was Cu(OH)(2) NPs, and 2.6% was dissolved copper ions (Cu(2+)). This method showed good applicability to different concentrations of Cu(OH)(2) NPs and different farmland soils. It also showed significant differences in the extraction rates of copper oxide nanoparticles (CuO NPs), Cu(2+), and other copper sources. The addition of a small amount of silica was confirmed to improve the extraction rate of Cu(OH)(2) NPs. The establishment of this method lays the foundation for the quantitative analysis of nano-pesticides and other non-spherical and slightly soluble nanoparticles.
摘要:
With the extensive development of industrial livestock and poultry production, a considerable part of agricultural wastewater containing tremendous ammonium and antibiotics have been indiscriminately released into the aquatic systems, causing serious harms to ecosystem and human health. In this review, ammonium detection technologies, including spectroscopy and fluorescence methods, and sensors were systematically summarized. Antibiotics analysis methodologies were critically reviewed, including chromatographic methods coupled with mass spectrometry, electrochemical sensors, fluorescence sensors, and biosensors. Current progress in remediation methods for ammonium removal were discussed and analyzed, including chemical precipitation, breakpoint chlorination, air stripping, reverse osmosis, adsorption, advanced oxidation processes (AOPs), and biological methods. Antibiotics removal approaches were comprehensively reviewed, including physical, AOPs, and biological processes. Furthermore, the simultaneous removal strategies for ammonium and antibiotics were reviewed and discussed, including physical adsorption processes, AOPs, biological processes. Finally, research gaps and the future perspectives were discussed. Through conducting comprehensive review, future research priorities include: (1) to improve the stabilities and adaptabilities of detection and analysis techniques for ammonium and antibiotics, (2) to develop innovative, efficient, and low cost approaches for simultaneous removal of ammonium and antibiotics, and (3) to explore the underlying mechanisms that governs the simultaneous removal of ammonium and antibiotics. This review could facilitate the evolution of innovative and efficient technologies for ammonium and antibiotics treatment in agricultural wastewater.
作者机构:
[Yan, Binghua; Jin, Hongyu; Niu, Hongyu] College of Resources and Environment, Hunan Agricultural University, 410128, Changsha, China;[Jin, Hongyu] Yueyang Agricultural and Rural Development Group Co., Ltd., 414022, Yueyang, China;[Nie, Zimeng] School of Environment and Energy, South China University of Technology, Guangzhou 510006, China;[Tan, Ju] Changsha Environmental Monitoring Center Station, 410001, Changsha, China;[Huang, Shuie] Changsha Xinkaipu Water Purification Factory, 410002, Changsha, China
通讯机构:
[Haijun Yang] C;College of Resources and Environment, Hunan Agricultural University, 410128, Changsha, China
摘要:
Microbial consortia HY3 and JY3 with high degradation efficiency of 2-Diethylamino-4-hydroxy-6-methylpyrimidine (DHMP) were isolated from aerobic and parthenogenic ponds of DHMP-containing pharmaceutical wastewater, respectively. Both consortia were enriched and reached stable degradation performance with a DHMP concentration of 1500mgL(-1). The DHMP degradation efficiencies of HY3 and JY3 were 95.66%±0.24% and 92.16%±2.34% under the condition of shaking at 180 r·min(-1) and the temperature of 30°C for 72h. And the removal efficiencies of chemical oxygen demand were 89.14%±4.78% and 80.30%±11.74%, respectively. High-throughput sequencing results indicated that three bacterial phyla of Proteobacteria, Bacteroidetes, and Actinobacteria were dominant in both HY3 and JY3, but their dominances varied. At the genus level, the richness of Unclassified Comamonadaceae (34.23%), Paracoccus (14.75%), and Brevundimonas (13.94%) ranked top three in HY3 whereas Unclassified Comamonadaceae (40.80%), Unclassified Burkholderiales (13.81%) and Delftia (13.11%) were dominant in JY3. The metabolites of DHMP degradation by HY3 and JY3 were analyzed in detail. Two pathways for cleavage of the nitrogenous heterocyclic ring were speculated, one of which was identified for the first time in this study.