scholarly journals Nitrate and Ammonium Affect the Overall Maize Response to Nitrogen Availability by Triggering Specific and Common Transcriptional Signatures in Roots

2020 ◽  
Vol 21 (2) ◽  
pp. 686 ◽  
Author(s):  
Laura Ravazzolo ◽  
Sara Trevisan ◽  
Cristian Forestan ◽  
Serena Varotto ◽  
Stefania Sut ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Negative Regulator ◽  
N Availability ◽  
Nitrogen Forms ◽  
Inorganic N ◽  
Comprehensive Information ◽  
Response To Stress ◽  
Distinct Features ◽  
Maize Response ◽  
Amino Acid Concentrations

Nitrogen (N) is an essential macronutrient for crops. Plants have developed several responses to N fluctuations, thus optimizing the root architecture in response to N availability. Nitrate and ammonium are the main inorganic N forms taken up by plants, and act as both nutrients and signals, affecting gene expression and plant development. In this study, RNA-sequencing was applied to gain comprehensive information on the pathways underlying the response of maize root, pre-treated in an N-deprived solution, to the provision of nitrate or ammonium. The analysis of the transcriptome shows that nitrate and ammonium regulate overlapping and distinct pathways, thus leading to different responses. Ammonium activates the response to stress, while nitrate acts as a negative regulator of transmembrane transport. Both the N-source repress genes related to the cytoskeleton and reactive oxygen species detoxification. Moreover, the presence of ammonium induces the accumulation of anthocyanins, while also reducing biomass and chlorophyll and flavonoids accumulation. Furthermore, the later physiological effects of these nutrients were evaluated through the assessment of shoot and root growth, leaf pigment content and the amino acid concentrations in root and shoot, confirming the existence of common and distinct features in response to the two nitrogen forms.

Impact of tillage and landscape position on nitrogen availability and yield of spring wheat in the Brown soil zone in southwestern Saskatchewan

1998 ◽  
Vol 78 (3) ◽  
pp. 563-572 ◽  
Author(s):  
V. Jowkin ◽  
J. J. Schoenau
Keyword(s):  
Spring Wheat ◽  
Nitrogen Availability ◽  
N Uptake ◽  
Wheat Crop ◽  
N Availability ◽  
Inorganic N ◽  
Brown Soil ◽  
Soil Zone ◽  
No Till ◽  
Crop N Uptake

Nitrogen availability to a spring wheat crop was examined in the cropping season in a side-by-side comparison of no-till (first year) and tillage fallow in an undulating farm field in the Brown soil zone in southwestern Saskatchewan. Thirty different sampling points along a grid in each tillage landscape were randomly selected, representing 10 each of shoulder, footslope and level landscape positions. Nitrogen availability was studied i) by profile inorganic N content ii) by crop N uptake and yield of spring wheat (Triticum aestivum L.) and iii) by 15N tracer technique and in situ burial of anion exchange resin membranes (AEM).Pre-seeding available moisture content of the surface soil samples was significantly higher under no-till compared with tillage fallow. However, no significant differences in pre-seeding profile total inorganic N, crop N uptake and yield were observed between the treatments. At the landform scale, shoulder positions of the respective tillage systems had lower profile inorganic N, crop N uptake and yield compared with other slope positions. Soil N supply power, as determined by 15N tracer and AEM techniques, was not significantly different between the tillage treatments, indicating that N availability is not likely to be greatly affected in initial years by switching to no-till fallow in these soils under normal moisture conditions. Key words: Summerfallow, landscape, nitrogen, wheat

scholarly journals Defoliation severity is positively related to soil solution nitrogen availability and negatively related to soil nitrogen concentrations following a multi-year invasive insect irruption

AoB Plants ◽  
2020 ◽  
Vol 12 (6) ◽  
Author(s):  
Emma Conrad-Rooney ◽  
Audrey Barker Plotkin ◽  
Valerie J Pasquarella ◽  
Joseph Elkinton ◽  
Jennifer L Chandler ◽  
...  
Keyword(s):  
Soil Solution ◽  
Nitrogen Availability ◽  
Spatial Scales ◽  
Landsat Imagery ◽  
N Cycling ◽  
Tree Level ◽  
N Availability ◽  
Inorganic N ◽  
Invasive Insect ◽  
Oak Trees

Abstract Understanding connections between ecosystem nitrogen (N) cycling and invasive insect defoliation could facilitate the prediction of disturbance impacts across a range of spatial scales. In this study we investigated relationships between ecosystem N cycling and tree defoliation during a recent 2015–18 irruption of invasive gypsy moth caterpillars (Lymantria dispar), which can cause tree stress and sometimes mortality following multiple years of defoliation. Nitrogen is a critical nutrient that limits the growth of caterpillars and plants in temperate forests. In this study, we assessed the associations among N concentrations, soil solution N availability and defoliation intensity by L. dispar at the scale of individual trees and forest plots. We measured leaf and soil N concentrations and soil solution inorganic N availability among individual red oak trees (Quercus rubra) in Amherst, MA and across a network of forest plots in Central Massachusetts. We combined these field data with estimated defoliation severity derived from Landsat imagery to assess relationships between plot-scale defoliation and ecosystem N cycling. We found that trees in soil with lower N concentrations experienced more herbivory than trees in soil with higher N concentrations. Additionally, forest plots with lower N soil were correlated with more severe L. dispar defoliation, which matched the tree-level relationship. The amount of inorganic N in soil solution was strongly positively correlated with defoliation intensity and the number of sequential years of defoliation. These results suggested that higher ecosystem N pools might promote the resistance of oak trees to L. dispar defoliation and that defoliation severity across multiple years is associated with a linear increase in soil solution inorganic N.

Short-term nitrogen dynamics in soil amended with fresh and composted cattle manures

1994 ◽  
Vol 74 (2) ◽  
pp. 147-155 ◽  
Author(s):  
J. W. Paul ◽  
E. G. Beauchamp
Keyword(s):  
Beef Cattle ◽  
Nitrogen Availability ◽  
N Uptake ◽  
Cattle Manure ◽  
N Availability ◽  
Inorganic N ◽  
Available Nitrogen ◽  
Higher Temperature ◽  
Manure Amendments ◽  
Amended Soil

The amount of available nitrogen in fresh and composted manures is required to adjust inorganic fertilizer applications for crops when using manures and composts. Corn (Zea mays L.) plants were grown for 8 wk at temperatures of 17–27 °C and 12–18 °C in soil amended with two rates of fresh and composted solid beef cattle manure. Apparent N uptake of corn grown in soil amended with fresh solid beef cattle manure, composted beef cattle manure and (NH4)2SO4 at the higher temperature was 2, 8, and 36%, respectively, during this 8-wk period. Nitrogen uptake by corn in fresh solid beef cattle manure-amended soil at low temperature was affected by factors other than N availability. A 12-wk laboratory experiment was performed in which 15NH4+ was added to fresh and composted manure-amended soil to determine the fate of the inorganic N in the manure and to measure N mineralization rates. Net immobilization of inorganic N occurred with all manures; however, after 3 wk, net mineralization occurred with the solid and composted beef cattle manure. Immobilization of 15N continued with all manure amendments as a result of mineralization-immobilization turnover. The amount of unrecovered 15N after 12 wk was 10.5, 2 and 1% of the added 15N in soil amended with solid beef cattle manure, composted beef cattle manure and manure composted with bark, respectively. Key words: Composted manure, nitrogen availability, 15N, immobilization, remineralization, temperature

scholarly journals Widely naturalized species are not more promiscuous in the use of different nitrogen forms, but benefit more from inorganic nitrogen

2021 ◽  
Author(s):  
Jianjun Zeng ◽  
Yanjie Liu ◽  
Mark van Kleunen
Keyword(s):  
Alien Species ◽  
Inorganic Nitrogen ◽  
Experimental Studies ◽  
Invasion Success ◽  
Mineral Nutrient ◽  
Organic N ◽  
N Availability ◽  
Nitrogen Forms ◽  
Inorganic N ◽  
Different Levels

Nitrogen (N) is an essential mineral nutrient necessary for plant growth and has been considered a crucial factor influencing invasion success. Former studies mainly focused on responses of alien plants to different levels of N availability. However, in natural soils, N comes in different forms. Few experimental studies have explored responses of naturalized alien species to different N forms, and whether such responses are related to their naturalization success globally. We selected 22 common herbaceous species native to Germany that have all become naturalized and thus been introduced elsewhere in the world. We grew these species under six different N conditions that differed in the amount or form of N, and assessed their growth performance in a greenhouse experiment. We found that plants produced more biomass when grown under high N levels than under low N levels, and when N was provided in inorganic form than when provided in organic form. Neither biomass production nor promiscuity to different N forms was related to naturalization success of the species. However, the biomass response to inorganic N, relative to organic N, was stronger for the widely naturalized species than for the less widely naturalized ones. Our study shows that although the widely naturalized alien species were not more promiscuous than the less widely naturalized species, they took more advantage of the inorganic-N forms. This indicates that naturalization success might be partly driven by a species' ability to take advantage of increased inorganic N levels.

Liming improves soil microbial growth, but trash blanket placement increases labile carbon and nitrogen availability in a sugarcane soil of subtropical Australia

Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 235 ◽  
Author(s):  
X. Y. Liu ◽  
M. Rezaei Rashti ◽  
M. Esfandbod ◽  
B. Powell ◽  
C. R. Chen
Keyword(s):  
Soil Ph ◽  
Enzyme Activities ◽  
Nitrogen Availability ◽  
Microbial Community Composition ◽  
Cropping System ◽  
Hot Water ◽  
Microbial Biomass C ◽  
N Availability ◽  
Total N ◽  
Soil Microbial

Liming has been widely used to decrease soil acidity, but its effects on soil nitrogen (N) availability and microbial processes in sugarcane fields are largely unknown. Adjacent sugarcane soils at 26 months after liming (26ML), 14 months after liming (14ML) and with no lime amendment (CK) in Bundaberg, Australia, were selected to investigate the effect of liming on soil N bioavailability and microbial activity in a long-term subtropical sugarcane cropping system. Liming in both 14ML and 26ML treatments significantly increased soil pH (by 1.2–1.4 units) and exchangeable Ca2+ (>2-fold) compared with the CK treatment. The lower concentrations of hot water extractable organic carbon (C) and total N and ammonium-N in the 14ML, compared with the CK and 26ML treatments, can be attributed to the absence of trash blanket placement in the former. Enhanced microbial immobilisation due to improved soil pH by liming (14ML and 26ML treatments) led to increased soil microbial biomass C and N, particularly in the presence of a trash blanket (26 ML treatment), but decreased soil respiration and metabolic quotient indicated that acidic stress conditions were alleviated in the liming treatments. Soil pH was the main factor governing soil enzyme activities, with an overall decrease in all enzyme activities in response to liming. Overall, liming and trash blanket practices improved sugarcane soil fertility. Further study is warranted to investigate the shifts in soil microbial community composition and the diversity and abundance of N-associated functional genes in response to liming in sugarcane fields.

scholarly journals Reviews and syntheses: measuring ecosystem nitrogen status – a comparison of proxies

2016 ◽  
Vol 13 (18) ◽  
pp. 5395-5403 ◽  
Author(s):  
Maya Almaraz ◽  
Stephen Porder
Keyword(s):  
N Mineralization ◽  
Nitrogen Availability ◽  
N Availability ◽  
Net N Mineralization ◽  
Tropical Regions ◽  
Net Nitrification ◽  
Kendall’S Τ ◽  
Soil Δ15n ◽  
N Status

Abstract. There are many proxies used to measure nitrogen (N) availability in watersheds, but the degree to which they do (or do not) correlate within a watershed has not been systematically addressed. We surveyed the literature for intact forest or grassland watersheds globally, in which several metrics of nitrogen availability have been measured. Our metrics included the following: foliar δ15N, soil δ15N, net nitrification, net N mineralization, and the ratio of dissolved inorganic to organic nitrogen (DIN : DON) in soil solution and streams. We were particularly interested in whether terrestrial and stream based proxies for N availability were correlated where they were measured in the same place. Not surprisingly, the strongest correlation (Kendall's τ) was between net nitrification and N mineralization (τ  =  0.71, p < 0.0001). Net nitrification and N mineralization were each correlated with foliar and soil δ15N (p < 0.05). Foliar and soil δ15N were more tightly correlated in tropical sites (τ  =  0.68, p < 0.0001), than in temperate sites (τ  =  0.23, p  =  0.02). The only significant correlations between terrestrial- and water-based metrics were those of net nitrification (τ  =  0.48, p  =  0.01) and N mineralization (τ  =  0.69, p  =  0.0001) with stream DIN : DON. The relationship between stream DIN : DON with both net nitrification and N mineralization was significant only in temperate, but not tropical regions. To our surprise, we did not find a significant correlation between soil δ15N and stream DIN : DON, despite the fact that both have been used to infer spatially or temporally integrated N status. Given that both soil δ15N and stream DIN : DON are used to infer long-term N status, their lack of correlation in watersheds merits further investigation.

scholarly journals Regulation and role of suppressor of cytokine signaling-3 in hypothalamic 4B cells

2009 ◽  
Vol 201 (3) ◽  
pp. 369-376 ◽  
Author(s):  
Kazunori Kageyama ◽  
Komaki Hanada ◽  
Yasumasa Iwasaki ◽  
Toshihiro Suda
Keyword(s):  
Gene Expression ◽  
Stress Responses ◽  
Negative Regulator ◽  
Cytokine Signaling ◽  
Mrna Levels ◽  
Suppressor Of Cytokine Signaling ◽  
Hypothalamic Cells ◽  
Parvocellular Neurons ◽  
Response To Stress ◽  
Inhibitory Signaling

Corticotropin-releasing factor (CRF) plays a central role in regulating stress responses. In the hypothalamic paraventricular nucleus (PVN), CRF, produced in response to stress, stimulates the release of ACTH from the anterior pituitary. ACTH then stimulates the release of glucocorticoids from the adrenal glands; circulating glucocorticoids are critical for recovery from stress conditions. Cytokines are also implicated in the regulation of CRF expression. Among them, interleukin (IL)-6 plays a role in the regulation of CRF. Factors other than glucocorticoids are likely to be involved in limiting the stimulation of CRF during stress. Suppressor of cytokine signaling (SOCS)-3 acts as a potent negative regulator of cytokine signaling. Little is known about the ability of the inhibitory signaling pathways to limit activation of the CRF gene in parvocellular PVN neurons. Hypothalamic 4B cells are useful for exploring the mechanisms, because these cells show characteristics of the parvocellular neurons of the PVN. In the present study, we examined whether SOCS-3 is regulated by IL-6 and cAMP in hypothalamic 4B cells. We also explored the involvement of SOCS-3 in the regulation of CRF gene expression. SOCS-3 was found to be regulated by IL-6 and via the cAMP/protein kinase A pathway in the hypothalamic cells. SOCS-3 knockdown increased IL-6- or forskolin-induced CRF gene transcription and mRNA levels. Therefore, SOCS-3, induced by a cAMP stimulant and IL-6, would be involved in the negative regulation of CRF gene expression in hypothalamic cells.

Indices of soil nitrogen availability in five Tasmanian Eucalyptus nitens plantations

Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 719 ◽  
Author(s):  
M. T. Moroni ◽  
P. J. Smethurst ◽  
G. K. Holz
Keyword(s):  
Soil Solution ◽  
Nitrogen Availability ◽  
Native Forest ◽  
N Availability ◽  
Eucalyptus Nitens ◽  
Soil Nitrogen Availability ◽  
Mineral N ◽  
Total N ◽  
Available N ◽  
Total P

Several soil analyses were used to estimate available N in surface soils (0–10 cm) over a 2-year period at 5 sites that supported 1- to 4-year-old Eucalyptus nitens plantations, and once in subsoils (10–120 cm) at 3 of these sites. Soils were derived from basalt (1 site previously pasture, 1 Pinus radiate, and 2 native forest) or siltstone (previously native forest). Soil analyses examined were total N, total P, total C, anaerobically mineralisable N (AMN), hot KCl-extractable N (hot KCl-N), and NH4+ and NO3– in soil solution and KCl extracts. AMN, KCl-extractable NH4+ and NO3–, and soil solution NH4+ and NO3– varied considerably with time, whereas hot KCl-N, total N, total P, and total C were temporally stable except for a gradual decline in total C with time at one site. Only total P was correlated with net N mineralisation (NNM) across all sites (r2 = 0.91, P < 0.05, n = 5). At 2–3 years after planting, soil solution and KCl-extractable NO3– dropped below 0.1 mm N and 1 μg N/g soil, respectively, at sites with NNM ≤24 kg N/ha.year (n = 3). Sites with NNM ≤24 kg N/ha.year also had ≤0.8 Mg P/ha. Although concentrations of indices of soil N availability decreased with depth, the contribution of subsoil (10–120 cm depth) to total profile N availability was estimated to be at least twice that of the top 10 cm. At an ex-pasture site, high concentrations of mineral N were found at 75–105 cm depths (KCl-extractable N, 289.3 μg N/g soil; 2.8 mm mineral N in soil solution), which may have become available to plantations as their root systems developed.

scholarly journals Carbon Mineralization in a Soil Amended with Sewage Sludge-Derived Biochar

2019 ◽  
Vol 9 (21) ◽  
pp. 4481 ◽  
Author(s):  
Figueiredo ◽  
Coser ◽  
Moreira ◽  
Leão ◽  
Vale ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Co2 Emissions ◽  
Nitrogen Availability ◽  
Carbon Mineralization ◽  
Environmental Benefits ◽  
N Availability ◽  
Soil N ◽  
Total N ◽  
Soil N Availability ◽  
Organic Matter Stabilization

Biochar has been presented as a multifunctional material with short- and long-term agro-environmental benefits, including soil organic matter stabilization, improved nutrient cycling, and increased primary productivity. However, its turnover time, when applied to soil, varies greatly depending on feedstock and pyrolysis temperature. For sewage sludge-derived biochars, which have high N contents, there is still a major uncertainty regarding the influence of pyrolysis temperatures on soil carbon mineralization and its relationship to soil N availability. Sewage sludge and sewage sludge-derived biochars produced at 300 °C (BC300), 400 °C (BC400), and 500 °C (BC500) were added to an Oxisol in a short-term incubation experiment. Carbon mineralization and nitrogen availability (N-NH4+ and N-NO3−) were studied using a first-order model. BC300 and BC400 showed higher soil C mineralization rates and N-NH4+ contents, demonstrating their potential to be used for plant nutrition. Compared to the control, the cumulative C-CO2 emissions increased by 60–64% when biochars BC300 and BC400 were applied to soil. On the other hand, C-CO2 emissions decreased by 6% after the addition of BC500, indicating the predominance of recalcitrant compounds, which results in a lower supply of soil N-NH4+ (83.4 mg kg−1) in BC500, being 67% lower than BC300 (255.7 mg kg−1). Soil N availability was strongly influenced by total N, total C, C/N ratio, H, pore volume, and specific surface area in the biochars.

scholarly journals Nitrogen species specific phosphorus mineralization in temperate floodplain soils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mary R. Arenberg ◽  
Yuji Arai
Keyword(s):  
Phosphatase Activity ◽  
Agricultural Runoff ◽  
N Availability ◽  
Inorganic N ◽  
Acid And Alkaline Phosphatase ◽  
Floodplain Soils ◽  
Magnetic Resonance Spectroscopic Analysis ◽  
Phosphorus Mineralization ◽  
P Mineralization ◽  
Species Specific

AbstractAs an essential component of enzymes, higher N availability from agricultural runoff to forest soils may boost the activity of phosphatase, increasing the bioavailability of phosphate. The objective of this study was to evaluate P mineralization rates in temperate floodplain soils as a function of inorganic N species (i.e., ammonium and nitrate) and amendment rate (1.5–3.5 g N kg−1). Accordingly, the soil was amended with nitrate and ammonium, and P dynamics were monitored during a 40-day incubation. The addition of ammonium significantly boosted acid and alkaline phosphatase activity by 1.39 and 1.44 µmol p-nitrophenol P (pNP) g−1 h−1, respectively. The degree of increase was positively correlated with the amendment rate. Likewise, the P mineralization rate increased by 0.27 mg P kg−1 in the 3.5 g N kg−1 ammonium treatment. 31P nuclear magnetic resonance spectroscopic analysis further supported the reduction in organic orthophosphate diesters on day 30. Meanwhile, the addition of nitrate promoted P mineralization to a lesser degree but did not increase phosphatase activity. While floodplain soils have great potential to sequester anthropogenic P, high availability of inorganic N, especially ammonium, could promote P mineralization, potentially increasing P fertility and/or reducing P the sequestration capacity of floodplain soils.

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