Different Combinations Of Nitrogen Research Articles

Multiple-Criteria Decision Analysis for Effect of Shoot Growth at Difference Combination Nutrient Fertiliser NPK for Harumanis Mango

It is vital to have the correct fertiliser arrangement for effective tree development, fruit yield, and essential fruit quality. The amount of fertiliser suggested with adequate nutrition will be maintained in the soil to supply the needs of the trees as they grow throughout the various growth stages. This study evaluated the effect of different combinations of Nitrogen(N), Phosphorus(P), and Potassium(K) on the vegetative flush physiology of Harumanis mango (Mangifera Indica. L). Single and combinations of N (511g), P(511g), and K(255g) fertilisers were used, which were N, P, NP, and NPK throughout May 2021. The results revealed that the minimum number of mature green leaves and a higher number of healthy panicles were observed in the NPK-treated plants. Moreover, NPK treatment showed the lowest malformation intensity percentage compared to other fertiliser treatments. The data were analysed to obtain the best regrowth pattern of shoots using Multiple-Criteria Decision Analysis (MCDA) techniques. The results on the pattern of regrowth after pruning when federalised with NPK fertiliser showed that the maximum percentage of total vegetative flush was 87.5% and the remaining 12.5% did not reach a satisfactory level according to the MCDA analysis.

Effects of different fertilization practices on maize yield, soil nutrients, soil moisture, and water use efficiency in northern China based on a meta-analysis

The application of fertilizer to ensure the steady improvement of crop yield has become the main means of agricultural production. However, it remains to be determined whether fertilization practices with different combinations of nitrogen (N), phosphorus (P), potassium (K), and organic (O) fertilizers play a positive role in the sustainability of maize yield and the soil in which it is grown. Therefore,this meta-analysis extracted 2663 data points from 76 studies to systematically analyze and explore the effects of different fertilization measures on maize yield, soil nutrients, water content and water use efficiency (WUE) in northern China. Articles addressing this topic showed that fertilization effectively increased the soil nutrient content and maize yield. The soil organic matter (SOM) increased by 2.36 (N)–55.38% (NPO), total nitrogen content increased by 6.10 (N)–56.39% (NPO), available phosphorus content increased by 17.12 (N)–474.74% (NPO), and available potassium content changed by − 2.90 (NP)–64.40% (NPO). Soil moisture increased by 3.59% under a single organic fertilizer application and decreased by 4.27–13.40% under the other treatments. Compared with no fertilization, the yield increase of fertilized maize reached 11.65–220.42%. NP, NPK and NPKO contributed the most to increased yield in lithological, black and fluvo-aquic soils, respectively. The effects of different fertilization practices on maize yield varied in response to the same meteorological factors. The WUE increased from 9.51 to 160.72%. In conclusion, rational fertilization can improve the soil nutrient content and increase maize yield. The combined application of chemical and organic fertilizer showed the greatest increase in yield and WUE. Organic fertilizer application alone increased soil moisture. Our results provide a theoretical basis for fertilizer application and for improving the soil structure for maize cultivation in northern China.

Assessment of the yield and yield attributing characters of oat (Avena sativa L.) grown under different tillage methods and NPK fertilizer rates in semi-arid conditions

Field experiments were conducted to determine the effect of tillage practices and inorganic sources of different combinations of nitrogen, phosphorus, and potassium fertilizers on some physical properties of soil and the yield of oats. The main plots were tillage techniques of no-till (T1), tillage with a cultivator (T2), twice-disc harrow (T3), and moldboard plowing (T4). Split-plots were fertilizer treatments of F1 control without fertilizer, 70:45:50 kg ha−1 NPK (F2), 140:90:100 kg ha−1 NPK (F3), 210:135:150 kg ha−1 NPK (F4), and 280:180:200 kg ha−1 NPK (F5). Soil density, acidity, electrical conductivity, and soil organic carbon increased under T1, while saturated hydraulic conductivity decreased compared with other tillage practices. Soil bulk density and pH increased with increasing sampling depth, while electrical conductivity and soil organic carbon declined with depth. Results from this study indicated a reduction in saturated hydraulic conductivity with time. The highest grain yield was found in the T4 and T3. In contrast, the highest grain yield was observed under F4 and F5 fertilization treatments at location 1 and F5 and F4 treatments at location 2. There were significant differences in growth characteristics and yield components due to the influence of tillage practices and fertilization levels in both experiment locations.

Effect of Different Combinations of Nitrogen, Phosphorus and Potassium on Growth and Yield of Okra (Abelmoschus esculentus L.) under Rupandehi Condition

An experiment on effect of different combinations of nitrogen, phosphorous and potassium on growth and yield of okra (Abelmoschus esculentus L.) var. ArkaAnamika was conducted at Institute of Agriculture and Animal Science (IAAS), Paklihawa, Rupandehi during February 2017 to June 2017. The experiment was laid in Randomized Complete Block Design (RCBD) with seven treatments and three replications. The treatments 220:200:60 NPK Kg ha–1 (T1), 200:180:60 NPK Kg ha–1 (T2), 180:160:40 NPK Kg ha–1 (T3), 160:140:40 NPK Kg ha–1 (T4), 140:120:20 NPK Kg ha–1(T5), 120:100:20 NPK Kg ha–1 (T6) and Control (T7) were applied and the growth, yield and yield attributes of okra were studied. The result revealed that there were no significant differences (p=0.05 level by Duncan’s Multiple Range Test-DMRT) on plant height, number of leaves, number of branches, fruit length, fruit diameter, average number of fruit per plant and average marketable yield to the effect of different combination of NPK levels. However, the result showed that average marketable yield and total yield was found significant over the control and also the highest total yield (43.21 Mt/ha) was obtained at 160:140:40NPK Kg ha–1.

Trocas gasosas e eficiência fotoquímica de goiabeira irrigada com águas salinas e adubação nitrogenada-potássica

ABSTRACT The objective of this study was to evaluate the effects of different combinations of nitrogen and potassium fertilization on gas exchange and chlorophyll a fluorescence in seedlings of guava cv. Paluma irrigated with water of different salinity levels. The experiment was set up in a randomized block design and analyzed in 5 × 4 factorial scheme, with four replicates. The treatments were composed of the combination of the factor electrical conductivity of irrigation water - ECw (0.3, 1.1, 1.9, 2.7, and 3.5 dS m-1), with the factor combinations (C) formed from recommended doses of nitrogen (N) and potassium (K2O), 70% N + 50% K2O, 100% N + 75% K2O, 130% N + 100% K2O, and 160% N + 125% K2O. The fertilization combination 130% N + 100% K2O mitigated the effects of salt stress up to mean ECw of 1.3 dS m-1, resulting in increments in CO2 assimilation rate, transpiration, instantaneous carboxylation efficiency, and electron transport rate. For maximum quantum efficiency of photosystem II, only treatment irrigated with ECw 3.5 dS m-1 under the combination 160% N + 125% K2O showed damage to the photosynthetic apparatus.

Effect of Planting Date and Inorganic and Organic of Nitrogen on Growth and Yield of Kohlrabi (Brassica oleracea var. Gongylodes)

A field experiment was conducted on Kohlrabi (Brassica oleracea var. gongylodes) ‘White Vienna cv.’ at the Experimental Station of the Department of Horticulture and Landscape, College of Agriculture, Tikrit University, Salah al-Din, Iraq, during the winter season of 2021-2022 under drip irrigation system. This study aimed to investigate the effect of planting time and different combinations of nitrogen on the growth and yield of kohlrabi plants. Results showed that the first time of planting, 2/8 recorded the highest values in most characteristics of vegetative growth and all characteristics of yield. On the other hand, using a combination of nitrogen at 25% mineral + 75% organic improved plant growth and yield compared to different fertilizer combinations of nitrogen. Interaction treatment between the first time of planting 2/8 and a combination fertilizer of nitrogen at 25% mineral + 75% organic gave the best growth and increased total yield compared with other interaction treatments.

Growth and production of crisp lettuce (Lactuca sativa L.) using different doses of nitrogen and magnesium

Lettuce is part of the group of leafy vegetables that sees high consumption worldwide. However, population increases have forced excessive increases in fertilization, raising N levels both in the water and the soil and leading to serious environmental problems. As a result, appropriate fertilization management must be carried out; therefore, this study aimed to determine the effect of nitrogen and magnesium on the growth and yield of crisp lettuce. A randomized complete block design was carried out with 10 treatments: a control plus nine treatments with a central compound and different combinations of nitrogen and magnesium doses. The variables leaf area ratio, SPAD chlorophyll index and relative growth rate decreased throughout the crop cycle. The application of 150 kg ha-1 of N + 18 kg ha-1 of Mg generated the highest production values and net assimilation rate. The response surface graph yielded a model with a maximum yield of 21 t ha-1 using fertilization with 93.8 kg ha-1 of nitrogen and 12.4 kg ha-1 of magnesium. The lower doses of both nitrogenous and magnesium fertilization showed the highest values of agronomic efficiency and partial productivity.

Effect of Nitrogen, Zinc and Iron on Growth and Yield of Baby-corn (Zea mays L.) Prayagraj Condition

A field experiment was conducted at the Crop Research Farm (CRF), Department of Agronomy, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences (SHUATS), Prayagraj (UP) during the year 2021 zaid season. To find out suitable Nitrogen, zinc and iron levels for profitable baby corn yield. The experiment comprised of 9 treatments with different combinations of nitrogen, zinc and iron replicated thrice in a Randomized Block Design. The main objective of the experiment was to evaluate the Effect of Nitrogen, Zinc and Iron on growth and yield of baby-corn (Zea mays L.). The nitrogen levels include [70, 80 and 90 kg/ha] where-as levels of zinc (0.5%) and iron (0.2%) From the present investigation The results showed that viz: Plant height (169.75 cm),Number of leaves per plant (13.80) plant dry weight (113.09 g/plant) were recorded significantly higher in 90kg/ha Nitrogen along with 0.5% Zinc and 0.2% Iron. Number of cobs per plant (1.69), cob length (18.50 cm), cob girth (8.10cm), cob weight with husk (48.85g), cob weight with out husk (13.80 g), cob yield with husk (11.75 t/ha), cob yield without husk (4.35 t/ha), green fodder (33.58t/ha) and the profitable production of baby corn can be secured by 90kg/ha Nitrogen + [0.5% Zinc + 0.2% Iron].

Optimal NPK Fertilizer Combination Increases Panax ginseng Yield and Quality and Affects Diversity and Structure of Rhizosphere Fungal Communities.

Soil microorganisms affect crop rhizospheres via the transformation and transport of nutrients, which has important influences on soil fertility, carbon sequestration, and plant yield and health in agroecosystems. There are few reports on the effects of fertilizer application on the growth of Panax ginseng (C. A. Mey.) or the structure of its rhizosphere microbial communities. In this study, an orthogonal experimental design was used to explore the effects of nine different combinations of nitrogen (N), phosphorus (P), and potassium (K) fertilizers with different amounts and proportions on ginseng growth and accumulation of ginsenosides and the structure of rhizosphere soil fungal communities. Soil without fertilization was the control. With the combined application of NPK, ginseng growth and development increased. The fertilization scheme N3P1K3, with N fertilizer at 50 g·m−2, P fertilizer at 15 g·m−2, and K fertilizer at 60 g·m−2, had the most comprehensive benefit and significantly increased ginseng rhizome biomass and ginsenoside contents (Rg1, Re, Rf, Rg2, Rb1, Ro, Rc, Rb2, Rb3, and Rd). Amplicon sequencing showed that NPK application increased the diversity of fungal communities in ginseng rhizospheres, whereas richness was bidirectionally regulated by proportions and amounts of NPK. Ascomycota was the dominant fungal phylum in ginseng rhizosphere soil, and relative abundances decreased with combined NPK application. Combined NPK application increased the relative abundance of potential beneficial fungi, such as Mortierella, but decreased that of potentially pathogenic fungi, such as Fusarium. Correlation analysis showed that potential beneficial fungi were significantly positively correlated with ginseng rhizome yield and ginsenoside contents, whereas the opposite relation was observed with potential pathogenic fungi. Thus, in addition to directly increasing crop growth, precise NPK application can also increase crop adaptability to the environment by shaping specific microbial communities. The results of this study suggest that the combined effects of biotic and abiotic processes on agricultural production determine crop yield and quality.

Effect of Nitrogen and Phosphorus on Growth and Yield of Cowpea [Vigna unguiculata L.

A field study was conducted during the growing season of 2021 at the crop research farm of the Department of Agronomy at Sam Higginbottom University of Agriculture, Technology, and Sciences, Prayagraj in the North Eastern plains of Eastern Uttar Pradesh with the objective of studying the effects of nitrogen and phosphorus on growth, yield, and economics of cowpea (Vigna unguiculata L.) Var. Gomati VU 89 under a randomised block design, comprising of 9 treatments, of which treatments (T1-T9) with different combinations of nitrogen and phosphorus, which are replicated thrice. The experimental results revealed that 25 kg N/ha + 50 kg P/ha recorded Maximum plant height (69.02 cm), number of branches/plant (12.33), number of nodules/plant (4.0), highest plant dry weight (15.32 gm), crop growth rate (4.80 g/m2/day), test weight (18.57 g), number of pods/plant (20.13), number of seeds/pod (15.1), seed yield (1243.97 kg/ha), harvest index (32.0%). T9 25 kg N/ha + 50 kg P/ha resulted in a higher net return (34.05 x 103/ha), gross return (63.44 x 103/ha), and benefit-cost ratio (2.16).

The effect of stressful ecological conditions on chlorophyll content in the leaves of spring wheat plants

In short-term vegetative experiment studied the effect of the different combinations of nitrogen and zinc fertilizers on the chlorophyll content in the leaves of spring wheat plants of the Zlata variety. It is established that application of nitrogen fertilizers together with zinc in most combinations contributed to stabilization of synthesis processes of chlorophyll grains in the leaves of wheat. It is shown that in conditions of optimal water supply and in the conditions of ecological stress caused by drought the most optimal combinations were ammonium sulfate with zinc and urea with zinc. With optimal water supply in variants where were applied ammonium sulfate with zinc and urea with zinc was obtained an increase of the amount of chlorophyll (a + b) compared with control variant without zinc, as a result of the growth of the content of both chlorophylls a and chlorophyll b. In the conditions of named ecological stress, the amount of chlorophyll (a+b) was increased in the variant with the addition of ammonium sulfate mainly due to chlorophyll a. In the variant where was applied urea with zinc the amount of chlorophylls (a+b) increased as a result of growth of chlorophyll a and chlorophyll b. It is shown that in conditions of drought in the specified variants had been increasing the ratio og chlorophyll a and chlorophyll b due to growth of chlorophyll b which indicates about improvement of water balance inside of the plant cells and increasing a photosynthetic activity due to normalization of processes of photolysis of water.

Shifts from complementarity to selection effects maintain high productivity in maize/legume intercropping systems

Abstract Complementarity (CE) and selection effects (SE) have been either invoked to explain the positive diversity–productivity relationship in natural and semi‐natural ecosystems. Few studies have, however, separated selection and complementarity effects in economically valuable intercropping systems, which receive significant nutrient inputs throughout the growing season. We performed a 2‐year field experiment with five cropping systems (i.e. maize/peanut intercropping, maize/soybean intercropping, maize, peanut and soybean monocultures) under different combinations of nitrogen (N) and phosphorus (P) fertilization. Sequential harvest of subplots was performed five times during the growing season and the additive partitioning method was applied to determine complementarity and selection effects in the two intercropping systems. We found that the land equivalent ratio (LER) based on yield was greater than or close to 1 in both maize/soybean and maize/peanut intercropping systems, suggesting yield advantages in these intercropping systems compared to monocultures. The LER of the two intercropping systems without N fertilization was greater in 2018 than in 2017. Nitrogen fertilization reduced the LER of maize/soybean intercropping in 2018, and that of maize/peanut intercropping across 2 years. Nitrogen fertilization had much stronger effects on maize yield than on soybean or peanut yield. Intercropping increased maize yield but decreased soybean and peanut yield. The CE was more important for net biodiversity effects without N fertilization while the SE was more important with N fertilization in the two intercropping systems across 2 years. Phosphorus fertilization impacts on the LER and biodiversity effects were weaker compared to N fertilization. Finally, net biodiversity effects were greater at later growth stages within a growing season. Synthesis and applications. Our study demonstrates how yield advantages of species‐diverse intercropping systems can be maximized either through (a) CE in the absence of N fertilization thanks to complementarity in nutrient use between crops or (b) SE under N fertilization thanks to overyielding of highly productive species (i.e. maize). Yield advantages promoted by CE are more sustainable because they are associated with reduced chemical fertilizer use and greater monetary benefits to farmers. These findings have important implications for the design and management of species‐diverse intercropping food‐production systems.

RUBBER TREE RESPONSE TO N, P and K DOSES IN FERTILIZATION AT PLANTING

The objective of this study was to evaluate the growth, root and shoot dry mass accumulation and nutritional status of rubber tree in the initial stage of cultivation, under different combinations of nitrogen (N), phosphorus (P) and potassium (K). Combinations of the following doses were tested: 0, 20, 40 and 80 kg ha-1 of N; 0, 75, 150 and 300 kg ha-1 of P2O5; and 0, 25, 50 and 100 kg of K2O. Under the soil and climate conditions analyzed, the combinations of NPK fertilization applied at planting only caused significant growth responses of rubber tree plants as a function of the absence of N and its presence at the dose of 80 kg ha-1. Through leaf analysis it was possible to verify that N fertilization and P fertilization are adequately meeting the needs of rubber tree plants, while the K doses tested did not reach the adequate levels of sufficiency.

Growth and gas exchange of West Indian cherry irrigated with saline waters under combinations of nitrogen-potassium fertilization

Fertilization management has been one of the techniques used to mitigate salt stress in crops. In this context, this research aimed to study the effect of different combinations of nitrogen and potassium fertilization on growth and gas exchange of the West Indian cherry crop irrigated with salinized water at different vegetative stages. The experiment was conducted in field, in a randomized block design, with treatments arranged in a 5 x 4 factorial scheme, referring to five irrigation water salinities (ECw): 0.3, 1.3, 2.3, 3.3 and 4.3 dS m-1 and four combinations of nitrogen and potassium doses: C1 = 70% + 50%; C2 = 100% + 75%; C3 = 130% + 100% and C4 = 160% + 125% of N and K2O, respectively, of the recommended dose for West Indian cherry, with three replicates and one plant per plot, consisting of a 60 L pot. Harmful effects of water salinity manifested at 230 days after transplantation (DAT) on the stem and primary shoot diameter, from ECw of 2.32 dS m-1 on, and the tested fertilizer combinations did not mitigate them. Fertilization with 70% N + 50% K2O favored gas exchange activity and higher plant growth from 170 DAT, regardless of water salinity.

Gas exchanges and growth of sesame (Sesamum indicum, L.) cultivated under saline waters and nitrogen-potassium fertilizers

The synergistic action between K and N (NO3-) favors the absorption of both ions by plants. A suitable combination of these macronutrients may be an alternative capable of alleviating the nutritional imbalance due to the excessive absorption of chloride and sodium by the plant and inhibitory competition between nitrate and potassium. In addition, it can favor the control of the turgidity of the cells, through the osmoregulation, elevate the synthesis of organic solutes, promoting the ionic homeostase, and consequently decrease the effect saline stress on the plants. In this context, this study aimed to evaluate the gas exchanges and growth of sesame cv. BRS G4 as a function of irrigation with water of increasing electrical conductivity (ECw) and fertilization with different combinations of nitrogen (N) and potassium (K). This experiment was conducted under greenhouse conditions. Treatments were distributed in randomized blocks and analyzed in 5 x 4 factorial scheme, consisting of five levels of ECw (0.6; 1.2; 1.8; 2.4 and 3.0 dS m-1) and four combinations of N and K: N/K2O (70/50; 100/75; 130/100 and 160/125% of the recommendation for pot experiments), with three replicates, totaling 60 experimental units. Except for the ECw level of 0.6 dS m-1, the other salt concentrations evaluated in this study compromised the gas exchanges and consequently growth of sesame cv. BRS G4, at 50 days after sowing. Fertilization with N and K in the combination of 70/50% of the recommendation of N/K2O led to the greatest growth of sesame cv. BRS G4. The N/K2O combinations of 130/100, 160/125 and 160/125% reduced the negative effects of saline irrigation of 1.2, 1.8 and 2.4 dS m-1, respectively, on the stomatal conductance of sesame plants. The combined supply of N and K2O in combinations of 100/75, 130/100 and 130/100% promoted higher CO2 assimilation rate in sesame plants using water of 1.2 and 1.8 and 2.4 dS m-1, respectively.

Degradation of complex casein polymer: Production and optimization of a novel serine metalloprotease from Aspergillus niger KIBGE-IB36

Abstract Serine metalloproteases have substantial scientific interest due to their unique physicochemical properties and capability to degrade complex casein polymer. In this contemporary study, the production of protease was enhanced by optimizing various physicochemical parameters and one-variable at a time approach used under submerged fermentation conditions. Among four different previously isolated Aspergillus species, Aspergillus niger KIBGE-IB36 represented high protease titer along with casein hydrolyzing zone on casein agar plate. Maximum protease production was achieved at 30 °C after 5 days of cultivation period at pH-6.0. Glucose (2.5 g L-1) and casein (2.5 g L-1) augmented protease production within the growth medium. Further increment in protease production was attained when different combinations of nitrogen and mineral salts concentrations used. Peptone (20.0 g L-1), yeast extract (0.50 g L-1), CaCl2 (0.10 g L-1), MgSO4 (0.10 g L-1) and K2HPO4 (0.30 g L-1) boosted the protease secretion. The current study is imperative for the large scale production of serine metalloprotease that also possess extraordinary prominence in food processing industries.

Morfofisiologia de aceroleira irrigada com águas salinas sob combinações de doses de nitrogênio e potássio

This research aimed to evaluate the effect of different combinations of nitrogen and potassium doses on the growth and physiology of the crop of the West Indian cherry irrigated with saline waters. The experiment was carried out in the field at the CCTA/UFCG, in a randomized block design, with treatments arranged in a 5 x 4 factorial scheme, referring to five irrigation water salinities (ECw) of 0.3, 1.3, 2.3, 3.3 and 4.3 dS m-1 and four combinations (C) of doses of nitrogen (N) and potassium (K2O), with C1 = 70% N + 50% K2O; C2 = 100% N + 75% K2O; C3 = 130% N + 100% K2O and C4 = 160% N + 125% K2O, with three replications, one plant per plot, totaling 60 plots without border. Most of the growth and physiological variables were not compromised by irrigation with water salinity up to 4.3 dS m-1 and, there was no salt stress mitigation by combinations of doses of nitrogen and potassium fertilization. The combination of the doses of 70% N (35 g of N) + 50% K2O (20 g of K2O per plant) was more effective in increasing the gas exchange, promoting greater plant growth.

Response of butter beans (Phaseolus lunatusL.) for different combinations of nitrogen and phosphorus on growth, yield and quality characters

Response of butter beans (Phaseolus lunatusL.) for different combinations of nitrogen and phosphorus on growth, yield and quality characters

Response of butter beans (Phaseolus lunatus L.) for different combinations of nitrogen and phosphorus on growth, yield and quality characters

A field experiment was conducted during June-October (2017) at Horticultural Research Station, Kodaikanal to study the response of butter beans for different combinations of nitrogen and phosphorus on growth, yield and quality characters. A randomized block design was followed with 17 combinations of N (30, 40, 50 and 60 kg/ha), P (37.5, 50, 62.5 and 75 kg/ha) and K 50 kg/ha was kept constant. The experimental results revealed that all the fertilizer treatments significantly increased the plant height, number of branches per plant, days to 50 % flowering, number of pods per cluster, 100 seed weight, pod weight, pod yield per hectare, protein content and crude fibre content of butter beans. Maximum plant height (220.33 cm), number of branches per plant (4.79), minimum days to 50 % flowering (50) and 100 seed weight were recorded in the combination of 50 kg N, 37.5 kg P 2 O 5 and 50 kg K 2 O per hectare. Number of pods per cluster (6.78), pod weight (14.00 g) and pod yield per hectare (5.85 t) were maximum in the combination of 60 kg N, 75 kg P 2 O 5 and 50 kg K 2 O per hectare.

How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels.

Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH4NO3) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in Triticum aestivum plants.