scholarly journals Moderately low nitrogen application mitigate the negative effects of salt stress on annual ryegrass seedlings

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10427
Author(s):  
An Shao ◽  
Zhichao Sun ◽  
Shugao Fan ◽  
Xiao Xu ◽  
Wei Wang ◽  
...  
Keyword(s):  
Salt Stress ◽  
Fluorescence Induction ◽  
Annual Ryegrass ◽  
Nitrogen Application ◽  
Negative Effects ◽  
Salt Treatment ◽  
N Application ◽  
Chl A ◽  
N Level ◽  
N Requirement

Appropriate application of nitrogen (N) can alleviate the salt stress-induced damage on plants. This study explores the changes of nitrogen requirement in feeding annual ryegrass seedlings under mild salt concentrations (50 mM, 100 mM) plus its underlying mitigation mechanism. Results showed that low salt concentration decreased N requirement as observed from the increment in plant height and biomass at a relative low N level (2.0 mM not 5.0 mM). Under salt treatment, especially at 50 mM NaCl, the OJIP (Chl a fluorescence induction transient) curve and a series of performance indexes (PIABS, RC/CS0, ET0/CS0, ϕE0, ϕ0) peaked whereas DI0/RC, Vj and M0 were the lowest under moderately low N level (2.0 mM). In addition, under salt stress, moderately low N application could maintain the expression of NR (nitrate reductase) and GS (glutamine synthetase) encoding genes at a relatively stable level but had no effect on the expression of detected NRT (nitrate transporter) gene. The seedlings cultured at 2.0 mM N also exhibited the highest activity of CAT and POD antioxidant enzymes and the lowest MDA content and EL under relative low level of salt treatment. These results indicated that mild salt treatment of annual ryegrass seedlings might reduce N requirement while moderately low N application could promote their growth via regulating photosynthesis, alleviating ROS-induced (reactive oxygen species) damage and maintenance of N metabolism. These results also can provide useful reference for nitrogen application in moderation rather than in excess on annual ryegrass in mild or medium salinity areas through understanding the underlying response mechanisms.

scholarly journals Paclobutrazol Reduces Some Negative Effects of Salt Stress in Peach

1997 ◽  
Vol 122 (1) ◽  
pp. 43-46 ◽  
Author(s):  
A.M. Abou El-Khashab ◽  
A.F. El-Sammak ◽  
A.A. Elaidy ◽  
M.I. Salama ◽  
M. Rieger
Keyword(s):  
Salt Stress ◽  
Prunus Persica ◽  
Leaf Gas Exchange ◽  
Plant Tissues ◽  
Negative Effects ◽  
Salt Treatment ◽  
Rooted Cuttings ◽  
Salt Stress Response ◽  
Stress Symptoms ◽  
One Year

One-year-old rooted cuttings of `Nemaguard' peach [Prunus persica (L.) Batsch.] were irrigated with 0, 1000, or 2000 mg·L-1 salts under greenhouse conditions to study the effect of foliar paclobutrazol (PBZ) application on salt stress response. Salinity reduced growth of nontreated plants by ≈60%, but only by ≈30% for PBZ-treated plants. PBZ-treated plants also had less defoliation and fewer leaves per plant showing salt stress symptoms, and had higher rates of leaf gas exchange than nontreated plants. PBZ application generally reduced Na+ and Cl- contents in leaves, roots, and stems, regardless of salt treatment. Furthermore, total Na+ per plant in PBZ-treated plants was about half that found in nontreated plants, although total Cl- per plant was reduced by PBZ in only one of two salt treatments. The data suggested that PBZ promoted salt stress avoidance in peach by reducing the uptake and accumulation of harmful Na+ and Cl- ions in plant tissues.

scholarly journals Criteria for topdressing nitrogen application to common bean using chlorophyll meter

2017 ◽  
Vol 52 (7) ◽  
pp. 512-520 ◽  
Author(s):  
Suelen Cristina Mendonça Maia ◽  
Rogério Peres Soratto ◽  
Suzane Maria Liebe ◽  
Adriana Queiroz de Almeida
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Nitrogen Application ◽  
N Application ◽  
Chlorophyll Meter ◽  
The Third ◽  
Chlorophyll Index ◽  
The Moment ◽  
N Rates ◽  
N Requirement

Abstract: The objective of this work was to establish the diagnostic leaf and the nitrogen sufficiency index (NSI) values most appropriate to estimate N requirement by the 'Pérola' common bean (Phaseolus vulgaris), based on chlorophyll meter monitoring. The diagnostic leaf was defined in an experiment with five N rates, and up to four sampling dates of the diagnostic leaves were evaluated (first, second, and third completely expanded leaves from the apex). The NSI was established in two crop seasons, under six N managements: M1, 40 kg ha-1 N at sowing + 80 kg ha-1 10 days after emergence (DAE) + 80 kg ha-1 20 DAE (reference rate); M2, 20 kg ha-1 at sowing + 40 kg ha-1 10 DAE + 40 kg ha-1 20 DAE (recommended rate); M3, 20 kg ha-1 at sowing + 30 kg ha-1 when NSI<96%; M4, 20 kg ha-1 at sowing + 30 kg ha-1 when NSI<93%; M5, 20 kg ha-1 N at sowing + 30 kg ha-1 when NSI<90%; and M6, without N application. The relative chlorophyll index readings on the second fully expanded leaf, at 21 DAE, and on the third leaf, at 28 and 35 DAE, are more precise to estimate the requirement of N by common bean. The NSI of 90% is more effective than the NSI of 93 or 96% for defining the moment for N topdressing application.

scholarly journals Simulating the Response of Drought–Tolerant Maize Varieties to Nitrogen Application in Contrasting Environments in the Nigeria Savannas Using the APSIM Model

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 76
Author(s):  
Aloysius Beah ◽  
Alpha Y. Kamara ◽  
Jibrin M. Jibrin ◽  
Folorunso M. Akinseye ◽  
Abdullahi I. Tofa ◽  
...  
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Production Systems ◽  
Agricultural Practices ◽  
Net Income ◽  
Nitrogen Application ◽  
N Application ◽  
Area Index ◽  
Support Tool ◽  
Maize Varieties

This paper assessed the application of the Agricultural Production Systems sIMulator (APSIM)–maize module as a decision support tool for optimizing nitrogen application to determine yield and net return of maize production under current agricultural practices in the Nigeria savannas. The model was calibrated for two maize varieties using data from field experiments conducted under optimum conditions in three locations during the 2017 and 2018 cropping seasons. The model was evaluated using an independent dataset from an experiment conducted under different nitrogen (N) levels in two locations within Southern and Northern Guinea savannas. The results show that model accurately predicted days to 50% anthesis and physiological maturity, leaf area index (LAI), grain yield and total dry matter (TDM) of both varieties with low RMSE and RMSEn (%) values within the range of acceptable statistics indices. Based on 31-year seasonal simulation, optimum mean grain yield of 3941 kg ha−1 for Abuja, and 4549 for Kano was simulated at N rate of 120 kg ha–1 for the early maturing variety 2009EVDT. Meanwhile in Zaria, optimum mean yield of 4173 kg ha–1 was simulated at N rate of 90 kg ha−1. For the intermediate maturing variety, IWDC2SYNF2 mean optimum yields of 5152, 5462, and 4849 kg ha−1, were simulated at N application of 120 kg ha−1 for all the locations. The probability of exceeding attainable mean grain yield of 3000 and 4000 kg ha−1 for 2009EVDT and IWDC2SYNF2, respectively would be expected in 95% of the years with application of 90 kg N ha−1 across the three sites. Following the profitability scenarios analysis, the realistic net incomes of US$ 536 ha–1 for Abuja, and US$ 657 ha−1 for Zaria were estimated at N rate of 90 kg ha−1 and at Kano site, realistic net income of US$ 720 ha–1was estimated at N rate of 120 kg ha−1 for 2009EVDT.For IWDC2SYNF2, realistic net incomes of US$ 870, 974, and 818 ha−1 were estimated at N application of 120 kg ha−1 for Abuja, Zaria, and Kano respectively. The result of this study suggests that 90 kg N ha−1 can be recommended for 2009EVDT and 120 kg N ha–1 for IWDC2SYNF2 in Abuja and Zaria while in Kano, 120 kg N ha−1 should be applied to both varieties to attain optimum yield and profit.

scholarly journals Evaluation of Indigenous Olive Biocontrol Rhizobacteria as Protectants against Drought and Salt Stress

2021 ◽  
Vol 9 (6) ◽  
pp. 1209
Author(s):  
Nuria Montes-Osuna ◽  
Carmen Gómez-Lama Cabanás ◽  
Antonio Valverde-Corredor ◽  
Garikoitz Legarda ◽  
Pilar Prieto ◽  
...  
Keyword(s):  
Salt Stress ◽  
Abiotic Stresses ◽  
Biochemical Parameters ◽  
Biocontrol Agent ◽  
Negative Effects ◽  
Experimental Conditions ◽  
Acds Gene ◽  
Drought And Salt Stress ◽  
Physiological And Biochemical

Stress caused by drought and salinity may compromise growth and productivity of olive (Olea europaea L.) tree crops. Several studies have reported the use of beneficial rhizobacteria to alleviate symptoms produced by these stresses, which is attributed in some cases to the activity of 1-aminocyclopropane-1-carboxylic acid deaminase (ACD). A collection of beneficial olive rhizobacteria was in vitro screened for ACD activity. Pseudomonas sp. PICF6 displayed this phenotype and sequencing of its genome confirmed the presence of an acdS gene. In contrast, the well-known root endophyte and biocontrol agent Pseudomonas simiae PICF7 was defective in ACD activity, even though the presence of an ACD-coding gene was earlier predicted in its genome. In this study, an unidentified deaminase was confirmed instead. Greenhouse experiments with olive ‘Picual’ plants inoculated either with PICF6 or PICF7, or co-inoculated with both strains, and subjected to drought or salt stress were carried out. Several physiological and biochemical parameters increased in stressed plants (i.e., stomatal conductance and flavonoids content), regardless of whether or not they were previously bacterized. Results showed that neither PICF6 (ACD positive) nor PICF7 (ACD negative) lessened the negative effects caused by the abiotic stresses tested, at least under our experimental conditions.

scholarly journals Application of Hyperspectral Imaging in the Assessment of Drought and Salt Stress in Magneto-Primed Triticale Seeds

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 835
Author(s):  
Jose Alvarez ◽  
Elvira Martinez ◽  
Belén Diezma
Keyword(s):  
Salt Stress ◽  
Hyperspectral Imaging ◽  
Human Observer ◽  
Negative Effects ◽  
Stress Symptoms ◽  
Data Variability ◽  
Drought And Salt Stress ◽  
The One ◽  
Almost All ◽  
Germination Parameters

Hyperspectral imaging is an appropriate method to thoroughly investigate the microscopic structure of internally heterogeneous agro-food products. By using hyperspectral technology, identifying stress symptoms associated with salinity, before a human observer, is possible, and has obvious benefits. The objective of this paper was to prove the suitability of this technique for the analysis of Triticale seeds subjected to both magneto-priming and drought and salt stress conditions, in terms of image differences obtained among treatments. It is known that, on the one hand, drought and salt stress treatments have negative effects on seeds of almost all species, and on the other hand, magneto-priming enhances seed germination parameters. Thus, this study aimed to relate hyperspectral imaging values—neither positive nor negative in themselves—to the effects mentioned above. Two main conclusions were reached: Firstly, the hyperspectral application is a feasible method for exploring the Triticale structure and for making distinctions under different drought and salt stress treatments, in line with the data variability obtained. Secondly, the lower spectral reflectance in some treatments—in the 400–1000 nm segment—is the result of a great number of chemical compounds in the seed that could be related to magneto-priming.

scholarly journals Optimizing Nitrogen Application for Growth and Productivity of Pomegranates

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 366
Author(s):  
Silit Lazare ◽  
Yang Lyu ◽  
Uri Yermiyahu ◽  
Yehuda Heler ◽  
Alon Ben-Gal ◽  
...  
Keyword(s):  
N Uptake ◽  
N Fertilization ◽  
Field Conditions ◽  
Nitrogen Application ◽  
N Application ◽  
Environmentally Responsible ◽  
Irrigation Solution ◽  
Vegetative Indices ◽  
Leaf N ◽  
Usage Efficiency

Quantification of actual plant consumption of nitrogen (N) is necessary to optimize fertilization efficiency and minimize contamination of earth resources. We examined the performance of fruit-bearing pomegranate trees grown in soilless media and exposed to eight N-fertigation treatments, from 5 to 200 mg N L−1. Reproductive and vegetative indices were found to be optimal when 20 to 70 mg N L−1 was supplied. Nitrogen application levels over 70 mg L−1 reduced pomegranate development and reproduction. N uptake in low-level treatments was almost 100% and decreased gradually, down to 13% in 200 mg N L−1 treatment. N usage efficiency was maximized under 20 mg N L−1, in which case 80% to 90% of added N was taken up by the trees. At high N application, its efficiency was reduced with less than 50% utilized by the trees. Leaf N increased to a plateau as a function of increasing irrigation solution N, maximizing at ~15 to 20 mg N g−1. Therefore, analysis of diagnostic leaves is not a valid method to identify excessive detrimental N. The results should be valuable in the development of efficient, sustainable, environmentally responsible protocols for N fertilization in commercial pomegranate orchards, following adaptation and validation to real soil field conditions.

scholarly journals Nitrogen Application and Leaf Harvesting Improves Yield and Nutritional Quality of Beetroot

2017 ◽  
Vol 27 (3) ◽  
pp. 337-343 ◽  
Author(s):  
Salfina S. Mampa ◽  
Martin M. Maboko ◽  
Puffy Soundy ◽  
Dharini Sivakumar
Keyword(s):  
Block Design ◽  
Root Diameter ◽  
Total Protein Content ◽  
Root Weight ◽  
Nitrogen Application ◽  
Root Yield ◽  
N Application ◽  
Leaf Yield ◽  
Leaf Harvest

Beetroot (Beta vulgaris), commonly known as table beet, is used as a staple in the diet of many people through the consumption of the entire plant, leaf, and the root. The objective of this study was to assess the effects of nitrogen (N) application and leaf harvest percentage on the yield and quality of roots and leaves of beetroot. The treatment design was a randomized complete block design with five levels of N (0, 60, 90, 120, and 150 kg·ha−1) combined with three leaf harvest percentages (0, 30, and 50) and replicated three times. The first leaf harvest was initiated 35 days after transplanting (DAT) by removing the outer matured leaves and the second harvest occurred 80 DAT by removing all the leaves. The results showed increases in leaf and root yield with an increase in N application. Nitrogen application at 90 and 120 kg·ha−1 increased fresh leaf weight, leaf number, and fresh and dry root weight, including root diameter and length with the exception of leaf area which was significantly higher at 120 kg·ha−1 N. Magnesium and iron leaf content, and N root content were significantly improved by the application of 120 kg·ha−1 N. Leaf harvest percentage did not have a significant effect on leaf yield or leaf and root mineral content. However, dry root weight was significantly reduced by the 50% leaf harvest. Leaf harvest at 30% or 50% increased total protein content of the roots of beetroot, whereas an increase in N application decreased concentration of total proteins. Results demonstrate that leaf and root yield, as well as magnesium, zinc, and iron leaf content, increased with the application of 120 kg·ha−1 N, whereas 30% leaf harvest did not negatively affect root yield.

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