The responses of carbon- and nitrogen-acquiring enzymes to nitrogen and phosphorus additions in two plantations in southern China

2019 ◽  
Vol 31 (4) ◽  
pp. 1319-1324 ◽  
Author(s):  
Senhao Wang ◽  
Taiki Mori ◽  
Jiangming Mo ◽  
Wei Zhang
Keyword(s):  
Southern China ◽  
Nitrogen And Phosphorus ◽  
Carbon And Nitrogen

Root Morphology and Secretion of two subtropical tree species to NH4+-N and NO3–-N Deposition

2020 ◽  
Author(s):  
Rui Zhang ◽  
Yi Wang ◽  
Zhichun Zhou
Keyword(s):  
Root Growth ◽  
Root System ◽  
Root Morphology ◽  
Tree Species ◽  
Southern China ◽  
N Deposition ◽  
Fibrous Root ◽  
Nitrogen And Phosphorus ◽  
Root Absorption ◽  
Tap Root

Abstract Background: Both NH4+ and NO3– are capable of greatly influencing plants’ growth and biomass. However, the belowground responses of subtropical trees to either NH4+ or NO3– deposition remain poorly understood. Here, we discuss how these two forms of N deposition can affect root development, and experimentally analyzed how they could impact nitrogen and phosphorus absorption in two types (broadleaved with a fibrous root system vs. conifer with a tap root system) of subtropical tree species. Results: In a greenhouse in southern China, 1-year-old S. superba and P. massoniana seedlings grown on P-limited and P-normal soil were treated with NaNO3 and NH4Cl solutions of 0, 80, and 200 kg N ha–1 year–1, corresponding to the control, N80, and N200 groups, respectively. Root phenotype characteristics and metabolism ability were measured after 8 months of growth. The results showed that the root morphology and physiology variables differed significantly between the two species under different N and P treatments. Although S. superba had a larger quantity of roots than P. massoniana, both its root growth rate and root absorption were respectively lower and weaker. N addition differentially affected root growth and activity as follows: (1) NO3–-N80 and NH4+-N80 increased root growth and activity of the two species, but NH4+-N80 led to thicker roots in S. superba; (2) NO3–-N200 and NH4+-N200 had inhibitory effects on the roots of P. massoniana, for which NH4+-N200 led to thinner and longer roots and even the death of some roots; and (3) NH4+-N could promote metabolic activity in thicker roots (> 1.5 mm) and the NO3–-N was found to stimulate activity in thinner roots (0.5–1.5 mm) in the fibrous root system having a larger quantity of roots, namely S. superba. By contrast, NO3–-N and NH4+-N had an opposite influence upon functioning in the tap root system with a slender root, namely P. massoniana. Conclusion: We conclude P. massoniana has a much higher root absorption efficiency; however, nitrogen deposition is more beneficial to the root growth of S. superba.

scholarly journals Effects of rainfall-runoff pollution on eutrophication in coastal zone: a case study in Shenzhen Bay, southern China

2019 ◽  
Vol 50 (4) ◽  
pp. 1062-1075 ◽  
Author(s):  
Hongliang Xu ◽  
Ying Zhang ◽  
Xiuzhen Zhu ◽  
Mingfeng Zheng
Keyword(s):  
Coastal Zone ◽  
Southern China ◽  
Fluid Dynamic ◽  
Storm Event ◽  
Rainfall Runoff ◽  
Pollution Load ◽  
Nitrogen And Phosphorus ◽  
Urban Catchments ◽  
Pollution Loads ◽  
Runoff Pollution

Abstract The concentration of human activities in coastal cities results in the increase of nutrient salts released into the coastal environment and is identified as a major environmental problem for coastal zone management. Large amounts of nitrogen and phosphorus are transported by rainwater-runoff from urban catchments to coastal zones during episodic rainfall events inducing eutrophication problems and increasing the risk of red tide occurrence. This study used a coupled model based on the Storm Water Management Model (SWMM) and Environment Fluid Dynamic Code (EFDC) to simulate the rainfall-runoff pollution load and its effects on eutrophication in Shenzhen Bay, southern China. A storm event of 2014 was used to build the modeling scenarios and thus analyzed the spatial-temporal variation of the rainfall-runoff pollution. The results indicated that: (i) rainfall-runoff pollution loads accounted for 60–80% of the total pollution loads, and rainfall-runoff pollution can result in a short-term impact pollution load on the receiving seawater body; (ii) the transportation of nutrient salts in the coastal zone and the nutrient salts absorbing process by algae are at different times, which suggests urban rainfall-runoff pollution has evidently an effect on variation of the concentration of chlorophyll-A in the bay, and with increasing distance to the city, the seawater body is gradually less affected by rainfall-runoff pollution.

Phytoplankton Productivity Changes in a Small, Double-Basin Lake in Response to Termination of Experimental Fertilization

1987 ◽  
Vol 44 (S1) ◽  
pp. s47-s54 ◽  
Author(s):  
J. A. Shearer ◽  
E. J. Fee ◽  
E. R. DeBruyn ◽  
D. R. DeClercq
Keyword(s):  
Numerical Model ◽  
Primary Production ◽  
The Other ◽  
Production Rates ◽  
Nitrogen And Phosphorus ◽  
Phytoplankton Productivity ◽  
Phytoplankton Primary Production ◽  
Carbon And Nitrogen ◽  
Model Technique ◽  
Reference Lakes

One basin of a small, double-basin lake was fertilized with carbon, nitrogen, and phosphorus for eight years, and then fertilization was stopped. The other basin was fertilized simultaneously with equivalent amounts of carbon and nitrogen only. Phytoplankton primary production was monitored using an incubator–numerical model technique. Production increased dramatically in the basin receiving artificial additions of C, N, and P. The increase was particularly large in the epilimnion where Cyanophyte blooms occurred during each year of fertilization and production rates averaged 2 to 10 times higher than in nearby, unfertilized reference lakes. Phosphorus, not nitrogen or carbon, was the critical nutrient. The productivity of the other basin also increased, but to a lesser degree and no Cyanophyte blooms were observed in this basin. When all fertilization was terminated, production in both basins immediately decreased. No more surface blooms were observed in either basin. Within 3 yr, the production had dropped to levels typical of reference lakes.

scholarly journals Soil Microbial Community Assembly and Interactions Are Constrained by Nitrogen and Phosphorus in Broadleaf Forests of Southern China

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 285 ◽  
Author(s):  
Mengxin Zhao ◽  
Jing Cong ◽  
Jingmin Cheng ◽  
Qi Qi ◽  
Yuyu Sheng ◽  
...  
Keyword(s):  
Microbial Community ◽  
Community Composition ◽  
Community Assembly ◽  
Soil Microbial Community ◽  
Southern China ◽  
Microbial Community Composition ◽  
Nitrogen And Phosphorus ◽  
Soil Microbial ◽  
Microbial Community Assembly ◽  
Microbial Functional Gene

Subtropical and tropical broadleaf forests play important roles in conserving biodiversity and regulating global carbon cycle. Nonetheless, knowledge about soil microbial diversity, community composition, turnover and microbial functional structure in sub- and tropical broadleaf forests is scarce. In this study, high-throughput sequencing was used to profile soil microbial community composition, and a micro-array GeoChip 5.0 was used to profile microbial functional gene distribution in four sub- and tropical broadleaf forests (HS, MES, HP and JFL) in southern China. The results showed that soil microbial community compositions differed dramatically among all of four forests. Soil microbial diversities in JFL were the lowest (5.81–5.99) and significantly different from those in the other three forests (6.22–6.39). Furthermore, microbial functional gene interactions were the most complex and closest, likely in reflection to stress associated with the lowest nitrogen and phosphorus contents in JFL. In support of the importance of environmental selection, we found selection (78–96%) dominated microbial community assembly, which was verified by partial Mantel tests showing significant correlations between soil phosphorus and nitrogen content and microbial community composition. Taken together, these results indicate that nitrogen and phosphorus are pivotal in shaping soil microbial communities in sub- and tropical broadleaf forests in southern China. Changes in soil nitrogen and phosphorus, in response to plant growth and decomposition, will therefore have significant changes in both microbial community assembly and interaction.

scholarly journals Novel Three-Component Phenazine-1-Carboxylic Acid 1,2-Dioxygenase in Sphingomonas wittichii DP58

2017 ◽  
Vol 83 (9) ◽  
Author(s):  
Qiang Zhao ◽  
Hong-Bo Hu ◽  
Wei Wang ◽  
Xian-Qing Huang ◽  
Xue-Hong Zhang
Keyword(s):  
Carboxylic Acid ◽  
Southern China ◽  
Nitrogen Sources ◽  
Content Type ◽  
Carbon And Nitrogen ◽  
Acid Degradation ◽  
Sphingomonas Wittichii ◽  
Encoding Gene ◽  
Encoding Genes

ABSTRACT Phenazine-1-carboxylic acid, the main component of shenqinmycin, is widely used in southern China for the prevention of rice sheath blight. However, the fate of phenazine-1-carboxylic acid in soil remains uncertain. Sphingomonas wittichii DP58 can use phenazine-1-carboxylic acid as its sole carbon and nitrogen sources for growth. In this study, dioxygenase-encoding genes, pcaA1A2, were found using transcriptome analysis to be highly upregulated upon phenazine-1-carboxylic acid biodegradation. PcaA1 shares 68% amino acid sequence identity with the large oxygenase subunit of anthranilate 1,2-dioxygenase from Rhodococcus maanshanensis DSM 44675. The dioxygenase was coexpressed in Escherichia coli with its adjacent reductase-encoding gene, pcaA3, and ferredoxin-encoding gene, pcaA4, and showed phenazine-1-carboxylic acid consumption. The dioxygenase-, ferredoxin-, and reductase-encoding genes were expressed in Pseudomonas putida KT2440 or E. coli BL21, and the three recombinant proteins were purified. A phenazine-1-carboxylic acid conversion capability occurred in vitro only when all three components were present. However, P. putida KT2440 transformed with pcaA1A2 obtained phenazine-1-carboxylic acid degradation ability, suggesting that phenazine-1-carboxylic acid 1,2-dioxygenase has low specificities for its ferredoxin and reductase. This was verified by replacing PcaA3 with RedA2 in the in vitro enzyme assay. High-performance liquid chromatography–mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR) analysis showed that phenazine-1-carboxylic acid was converted to 1,2-dihydroxyphenazine through decarboxylation and hydroxylation, indicating that PcaA1A2A3A4 constitutes the initial phenazine-1-carboxylic acid 1,2-dioxygenase. This study fills a gap in our understanding of the biodegradation of phenazine-1-carboxylic acid and illustrates a new dioxygenase for decarboxylation. IMPORTANCE Phenazine-1-carboxylic acid is widely used in southern China as a key fungicide to prevent rice sheath blight. However, the degradation characteristics of phenazine-1-carboxylic acid and the environmental consequences of the long-term application are not clear. S. wittichii DP58 can use phenazine-1-carboxylic acid as its sole carbon and nitrogen sources. In this study, a three-component dioxygenase, PcaA1A2A3A4, was determined to be the initial dioxygenase for phenazine-1-carboxylic acid degradation in S. wittichii DP58. Phenazine-1-carboxylic acid was converted to 1,2-dihydroxyphenazine through decarboxylation and hydroxylation. This finding may help us discover the pathway for phenazine-1-carboxylic acid degradation.

scholarly journals Pilot study on the treatment of low carbon and nitrogen ratio municipal sewage by AOAAO sludge-membrane coupling process with multi-point inflow

2021 ◽  
Author(s):  
Dewei Zhang ◽  
Jun-Tian Zheng ◽  
Jun Zheng ◽  
Meng-Ke Zhao ◽  
Meng-Lin Wang ◽  
...  
Keyword(s):  
Distribution Ratio ◽  
Phosphorus Removal ◽  
Removal Rate ◽  
Domestic Sewage ◽  
Low Carbon ◽  
Nitrogen And Phosphorus ◽  
Removal Rates ◽  
Coupling Process ◽  
Carbon And Nitrogen ◽  
Nitrogen Ratio

Abstract A new multi-point inflowA1/O2/A3/A4/O5 sludge-membrane coupling process and pilot plant were developed and designed to solve the problem of nitrogen and phosphorus removal of low C/N domestic sewage in southern China. By changing the distribution ratio of multi-point influent, the removal effect and transformation rule of organic matter, nitrogen and phosphorus in the system were studied. Results showed that when the average low C/N ratio of influent was 2.09 and the influent distribution ratio was 1:1, the average concentrations of COD, NH4+- N, TN and TP in the effluent were 21.31 mg/L, 0.60 mg/L, 12.76 mg/L and 0.34 mg/L, respectively, and the average removal rates are 87.3%, 98.7%, 74.1% and 88.1% respectively. When the low temperature was 12–15℃, the average removal rates were 87.3%, 98.7%, 74.1% and 88.1%, respectively. Compared with the traditional A2O process under the same conditions, the TN removal rate was increased by 15.4%, and the TP removal rate was increased by 22.2%. This system has obvious advantages in treating wastewater with low carbon and nitrogen ratio, which solved the problem that the effluent of biological phosphorus removal from low C/N ratio domestic sewage was difficult to be lower than 0.5 mg/L.

scholarly journals The effects of slope length and coverage ratio on nitrogen and phosphorus loss in red soil Regions of southern China

2019 ◽  
Vol 136 ◽  
pp. 07028
Author(s):  
Qian Jing ◽  
Zhang Liping
Keyword(s):  
Southern China ◽  
Soil Nutrient ◽  
Nutrient Loss ◽  
Vegetation Coverage ◽  
Soil Productivity ◽  
Slope Gradient ◽  
Point Source Pollution ◽  
Nitrogen And Phosphorus ◽  
Slope Length ◽  
Coverage Ratio

Soil nutrient loss not only reduces soil productivity, but also causes non-point source pollution and accelerates the eutrophication of surface water. In order to understand the effects of slope lengths (2m, 4m), vegetation coverage ratios (15%, 30%, 45%, 60%, 90%) on the mechanisms of soil nutrient loss, the research studied the simulated rainfall experiment with the slope gradient of 20°, the rainfall intensity of 2.0 mm/min and the time of producing runoff for about 30 min. The experimental results showed that the runoff coefficient is mainly affected by vegetation coverage ratio.

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