Nitrate Reductase Activity Values Research Articles

Responses of some soil enzymes and cotton plant to foliar application of ferrous sulfate in a calcareous alkaline soil

Ferrous sulfate application is important in improvement of agricultural production, elimination of micronutrient deficiencies in human and animal populations, and promotion of sustainable food and feed production. This study was carried out to investigate the effects of different doses of foliar iron sulfate (FeSO4) applications on cotton plant yield and yield components, soil enzyme activity and chlorophyll content (SPAD value) and Normalized Difference Vegetation Index (NDVI) values of cotton plants. The results of both growing periods indicated that 0.4% FeSO4 application dose was more effective than the other doses compared to the control (Co), therefore, the evaluations were carried out based on 0.4% FeSO4 application dose. The application dose increased the cotton yield by 20.53 and 19.08% in the 2020 and 2021 season, respectively. The SPAD value increased by 54.88 and 98.68% in the 2020 and 2021 season. The NDVI values were 0.83 and 0.85 in the 2020 and 2021 seasons, respectively. Soil enzymes responded positively to FeSO4 application. The urease enzyme activity at this application dose varied between 17.81 and 18.76 µg N g−1 dry soil h−1 (13.73 to 26.33% increase compared to Co), and the highest value was recorded in 2021. The Dehydrogenase (DHG) enzyme activity was between 18.38 and 16.05 µg TPF g−1 dry soil 24 h−1 (39.8 and 46.30% increase compared to Co). The Catalase enzyme activity (CAT) was 36.40 and 38.73 ml O2 g−1 dm 5 min−1 in (51.23 and 39.32% compared to control) and the highest value was recorded in 2021. Nitrate Reductase Activity (NRA) was 18.66 and 17.14 µg N g−1 dm 2 h−1 in 2020 and 2021 seasons. The values of NRA were 54.11 and 59.54% lower in 2020 and 2021 seasons compared to the NRA in Co.

Reduction of drought stress effect in spring barley (Hordeum vulgare L.) by nitrogen fertilization

An effect of nitrogen rates (0.0 g, 1.0 g, 2.0 g N per pot) on NRA (nitrate reductase activity) in leaves of spring barley (cultivar Kompakt) was investigated in a pot experiment. Plants were grown under optimum moisture regime and drought stress was induced during the growth stages of tillering, shooting and earing. Before and after respective stress period plants were grown under optimal water regime. In all the fertilized and unfertilized treatments, NRA was significantly higher under optimal water regime than in drought stress conditions. Nitrogen fertilization alleviated adverse effects of drought stress on the yields of grain; the rate of 1 g N per pot increased the grain yield of plants stressed during tillering 3.73 times compared to unfertilized and stressed treatment. When the stress was induced during shooting or earing grain yields declined by over 50% compared to optimal water regime; when compared with stressed and unfertilized treatment, the rate of 1 g N however increased yield by 29% (stress at shooting) and 55% (stress at earing). NRA values were significantly higher when plants were grown under optimum water regime than under stress conditions as well as when fertilized with nitrogen compared to unfertilized control both under optimum water regime and drought stress.

A study on nitrate reductase activity (NRA) of geophytes from Mediterranean environment

Nitrate reductase activity (NRA) in different compartments of 14 Mediterranean geophytes (bulbous, tuberous and rhizomatous) and actual mineral nitrogen (NO 3 − and NH 4 +) in their soils were investigated. The nitrate reduction capacities of each species were determined as NRA per total plant material. Differences among compartments for NRA were significant in all species. The highest NRA was found in leaves of tuberous species ( Anemone coronaria, Cyclamen coum) and of most bulbous species ( Allium flavum, Allium guttatum, Bellevelia sarmatica, Galanthus plicatus, Leucojum aestivum, Ornithogalum nutans, Tulipa sylvestris). Therefore, in this group of species the contribution of the leaves to total plant NRA was the highest. The other bulbous species ( Allium scorodoprasum, Crocus chrysanthus, Fritillaria bithynica, Muscari neglectum) and one rhizomatous taxon ( Iris suaveolens) have a different NRA distribution within the plants. In these species the highest values of NRA were found in different organs. For example, in Allium scorodoprasum the highest NRA was in tunics, and in flowers in M. neglectum. Although leaves are the main compartments reducing nitrate in most of the studied geophytes, other compartments also contribute to total plant nitrate reduction. Our results show that the nitrate reduction capacity is different among geophyte species. Even if it roughly reflects the nitrogen supply in a habitat, differences in nitrate reduction capacities of different species collected from same sites indicate that the nitrate reducing capacity is species-specific.

Nitrate reductase activity in leaves and stems of tanner grass (Brachiaria radicans Napper)

Tanner grass (Brachiaria radicans Napper) is a forage plant that is adapted to well-drained soils or wetlands, and responds well to nitrogen (N) fertilization. The assimilation of N involves the nitrate reductase (NR) enzyme, and its activity seems to be dependent on N supply. Molybdenum (Mo) is also important because it is a cofactor of NR. In this study, the variables of an in vivo assay were optimized for measuring nitrate reductase activity (NRA) in the leaves and stem tissues. This method was used to evaluate NO3- metabolism in plants fertilized with NaNO3, NH4Cl or urea, in association with or without application of H2MoO4, aiming to provide guidelines for N management of this species. The best conditions to determine NRA involved the incubation of 300 mg of tissues in a medium composed of 200 mmol dm3 phosphate buffer (pH 7.4), 60 mmol dm3 KNO3, 10 cm³ dm3 n-butanol, 0.1 cm³ dm3 detergent (triton-X-100®), under vacuum and in the dark for a period of 60 to 100 minutes. Leaves showed NRA levels two to three times higher than stems. Although there were some interactions between treatments, stem fresh weight and NRA were not affected by N sources. Plants fertilized with NaNO3 showed the best growth and NRA values when compared with NH4Cl and urea, which had, respectively, the lowest and intermediate scores. The application of Mo in the absence of N improved NRA and did not affect leaf and stalk growth. In the presence of N, the Mo levels applied limited leaf NRA and plant development.

The maximum nitrate reductase activity of the seagrass Zostera noltii (Hornem.) varies along its vertical distribution

Maximum nitrate reductase (NR) activity was measured in two intertidal morphotypes of Zostera noltii (Hornem.) in Ria Formosa tidal lagoon, southern Portugal. The two morphotypes develop in the upper and lower limits of the intertidal meadows. The NR activity was measured using an in vivo method, without cell disruption. NR activity was 30–40 fold higher in leaves than in roots, which indicates that nitrate reduction is essentially made through the aerial part of the plant. The effects of assay temperature (5 °C steps, from 5 to 45 °C), pH (7, 8 and 9) and elevation (upper and lower intertidal) on leaf NR activity were tested in a factorial design ( n=5). Both elevation and assay temperature had a significant effect on NR activity, but not pH. NR activity was always higher in the upper intertidal plants, at all temperatures. Activity peaks for upper and lower plants were, respectively, 6.12 μmol NO 2 − g −1 DW 0.5 h −1 at 25 °C, and 3.30 μmol NO 2 − g −1 DW 0.5h −1 at 35 °C. Further investigation on environmental factors concerning the intertidal environment must be developed, as they are probably responsible for the significant differences found between the values of NR activity in the upper and lower morphotype.

The effects of light and nitrate levels on the relationship between nitrate reductase activity and 15NO3− uptake: Field observations in the East China Sea

Nitrate reductase activity (NRA) and 15NO3− uptake (NU) were determined in the East China Sea and the adjoining Kuroshio in May 1996, at six stations covering a range of hydrographic conditions: the nutrient‐rich and fresherplume of Changjiang Diluted Water along the Chinese coast, the nutrient‐rich upwelling Kuroshio Subsurface Water at the shelf edge northeast of Taiwan, the oligotrophic Kuroshio Surface Water and the mixing zones among these water masses on the shelf. The values of NRA in the surface mixed layer ranged between 16 and 0.1 nM‐N h−1, whereas those of NU ranged between 37 and 1 nM‐N h−1. Higher NRA and NU were found in the frontal zone between the coastal and shelf waters and in the upwelling zone, whereas the lowest values were found in the surface Kuroshio. The NRA/Chl a ratio increased linearly with increasing NU/primary production ratio in the sequence: Kuroshio, coastal plume, upwelling zone and mixing zones in the shelf. This is probably a reflection of the varying nutrient condition and the relative importance of NU in sustaining the biomass in these regions.In nitrate‐ and light‐replete waters, the average NU/NRA was 1.0 ± 0.3. NRA was linearly related to NU so that NU = 1.08 (± 0.07)NRA (r2 = 0.79). Thus, NRA may be used for estimating NU in these waters. In nitrate‐deficient and light‐replete waters, the average NU/NRA was 4 ± 4. These high and variable values of NU/NRA might have been caused by an over‐estimation of NU as a result of the stimulatory effect of the added 15NO3− on phytoplankton growth. Thus, NRA may be a more reliable indicator of the rate of 15NO3− uptake in oligotrophic waters. In nitrate‐replete and light‐deficient waters, NU did not correlate well with NRA. The average NU/NRA was 0.7 ± 0.7. These low and variable values of NU/NRA suggest a possible decoupling between NRA and NU.By using the relationship between NU and NRA in nitrate‐ and light‐replete waters and the depth‐integrated inventory of NRA in the photic zone at each station, NU in oligotrophic waters, the coastal plume, upwelling waters and shelf waters can be estimated to be 0.45, 1.55, 3.12, and 3.59 mg‐N m−2 h−1 respectively. These values fall well within the range of previously reported values in similar types of water.

Nitrate Reductase Activity of Diverse Grain Sorghum Genotypes and Its Relationship to Nitrogen Use Efficiency

High crop N use efficiency is desirable for reducing the cost and reliance on fertilizer N, and it may help reduce ground water pollution. The objectives of this study were to (i) characterize and compare the seasonal trends in nitrate reductase activity (NRA) of seven grain sorghum [Sorghum bicolor (L.) Moench] genotypes of tropical and U.S. origin, (ii) determine how NRA is related to total plant N, dry matter, grain yield, and N use efficiency, and (iii) examine how NRA and plant N accumulation affect N use efficiency for biomass (NUE1) and grain production (NUE2). The genotypes were evaluated in field trials in 1994 and 1996 at applied N levels of 0 and 100 N kg ha−1 on a Sharpsburg silty clay loam soil (fine, smectitic, mesic Typic Argiudoll). Plant biomass, reduced N, NRA, NUE1, and NUE2 were determined at three growth stages (vegetative, anthesis, and physiological maturity). Genotypes did not differ for NRA at either N level; however, there was a definite tendency for the four tropical lines and two U.S. adapted lines to have greater NRA values at all growth stages than the one hybrid. Nitrate reductase activity decreased throughout the growing season, with the sharpest decline from anthesis to maturity. Nitrate reductase activity did not correlate with grain yield or shoot biomass, but did correlate with grain N concentration. Shoot and grain N concentration correlated with NUE1, while grain and shoot N contents and shoot N concentration were correlated with NUE2. Neither NUE1 nor NUE2 were significantly affected by the NRA level. Tropical lines had greater preanthesis N uptake accumulation (1.45 g plant−1) and greater NUE1 than the hybrid (0.90 g plant−1) and U.S. adapted lines (0.73 g plant−1). In terms of grain N use efficiency, the hybrid had a 14% greater value than U.S. adapted lines and a 17% greater value than the tropical lines. It appears that NRA is not a factor that limited N accumulation and use efficiency in grain sorghum.

Nitrate reductase activity in vegetation below an arctic bird cliff, Svalbard, Norway.

. Vegetated sites below bird‐nesting cliffs are uniquely nutrient‐rich habitats in the otherwise nutrient‐poor arctic environment. Plants from six distinct vegetation zones below such a cliff at 79° N, Svalbard, Norway, were collected for analysis under greenhouse conditions. Leaf nitrate reductase activity (NRA) was analysed in 42 species representing 25 % of the Svalbard vascular flora. The species mean NRA values ranged from 0.37 to 8.34 μmols of nitrite ions formed per gram of plant fresh weight per hour. Species in the vegetated zone growing closest to recent guano deposits had the highest NRA values, (mean = 4.47) whereas plants growing farther below the cliff had significantly lower values (mean = 0.55).A similar pattern was detected in a duplicate set of plants induced with 15 mM KNO3; vegetation zone means for NRA ranged from 5.08 to 0.98 μmols of nitrite ions formed per gram of plant fresh weight per hour. Maximally induced species NRA values were highest in the first zones below the cliff and decreased downslope. This gradient paralleled the steep soil nitrate gradient, which decreased from 13.84 mg/l at the cliffbase to 1.03 mg/l downslope. Correspondingly, soil ammonium ions in the vegetation zones ranged between 1.96 mg/l at the cliff‐base to 0.03 mg/l downslope. Correlations between NRA and soil nitrate provide a systematic basis for assigning scalar ‘nitrogen figures’ as indicators of habitat preference, here for the first time applied to arctic species.

Effect of nitrogen salts on nitrate reductase activity and protein contents in wheat (Triticum aestivum L.)

The effects of different nitrogen salts on nitrate reductase activity and protein contents were investigated in three Yugoslav cultivars of wheat. The nitrate salts appeared to be a better form of nitrogen than ammonium in respect of the increase of the nitrate reductase activity and root total protein contents, whereas the treatment with ammonium salt resulted in a comparably higher shoot total protein contents. KNO3 was the best in respect of the level of nitrate reductase activity. Different concentrations of nitrate and ammonium ions in nutrient solution, showed very similar effects on investigated parameters. NS Rana 2 cultivar had the highest values of nitrate reductase activity and protein contents.

Nitrate, nitrate reduction and organic nitrogen in plants from different ecological and taxonomic groups of Central Europe.

48 plant species of the families Asteraceae, Chenopodiaceae, Ericaceae, Fabaceae, Lamiaceae, Polygonaceae and Urticaceae were investigated in 14 natural habitats of Central Europe having different nitrate supplies, with respect to their nitrate content, nitrate reductase activity (NRA) and organic nitrogen content. Plants that were flowering were selected where possible for analysis. The plants were subdivided into flowers, laminae, petioles+shoot axes and below-ground organs. Each organ was analyzed separately. Differences among species were found for the three variables investigated. Apart from the Fabaceae, which had particularly high concentrations of organic N, these differences reflect mainly the ecological behaviour, i.e. high nitrate and organic N contents and NRA values per g dry weight were found in species on sites rich in nitrate, and vice versa. Nitrate content, NRA and organic N content were correlated with "nitrogen figures" of Central European vascular plants defined by Ellenberg (1979). By use of regression equations this correlation was tested with species from other systematic groups. Some species were attributed with calculated "N figures" for the first time.

Nitrogen

This work was performed in order to obtain information about the relation between plant N‐levels and yields by means in vivo nitrate reductase activity (NRA) determinations in leaves of tomato and cucumber. Plants were grown under glasshouse conditions in solutions containing different N‐levels. At different growth stages, leaves were sampled and NRA, total N and growth were determined. Ammonia and NO3‐N have a considerable influence on the NRA by way of the feedback mechanism and NRA was affected by growth stage. This, however, is dependent on nitrification conditions when soil is applied. In our conditions, maximum NRA values associated with maximum yield were approximately 3.40 ‐ 3.70 μmol NO2‐ formed (g fresh weight, hr)‐1 for tomato and 4.50 ‐ 4.70 μmol NO2 ‐ formed (g fresh weight, hr)‐1 for cucumber plants.

Biomass production and nitrate metabolism of Atriplex hortensis L. (C3 plant) and Amaranthus retroflexus L. (C4 plant) in cultures at different levels of nitrogen supply.

Pure and mixed cultures of the dicotyledons Atriplex hortensis L. (C3 plant) and Amaranthus retroflexus L. (C4 plant) were maintained under open air conditions in standard soil at low and high nitrogen supply levels.A comparison of shoot dry weight and shoot length in the various series shows that the growth of the aboveground parts of both species was severely reduced under low N conditions. In both pure and mixed cultures the differences resulting from low N vs. high N conditions was less pronounced with Atriplex (C3 plant) than with Amaranthus (C4 plant). The root dry weight of the two species was not reduced so much under low N conditions as was the shoot dry weight. The low N plants were found to contain a larger proportion of their biomass in the roots than did the high N plants. In general the root proportion of Atriplex was greater than that of Amaranthus. The contents of organic nitrogen and nitrate and the nitrate reductase activity (NRA) per g dry weight of both species decreased continually throughout the experiments. With the exception of young plants, the low N plants always had tower contents of organic nitrogen and nitrate and nitrate reductase activities than did the high N plants. The highest values of NRA were measured in the leaf laminae. The eaves also exhibited the highest concentrations of organic nitrogen. The highest nitrate concentrations, however, were observed in the shoot axis, and in most cases the lowest nitrate values were found in the laminae. At the end of ne growing season this pattern was found to have been reversed with Atriplex, but not with Amaranthus. Thus Atriplex was able to maintain a higher NRA in the laminae than Amaranthus under low N conditions.The transpiration per leaf area of the C4 plant Amaranthus during the course of a day was substantially lower than that of the C3 plant Atriplex. There were no significant differences in transpiration between the low N and high N series of Amaranthus. The low N plants of Atriplex, however, clearly showed in most cases higher transpiration rates than the corresponding high N plants. These different transpiration rates of the high N and the low N Atriplex plants were also reflected in a distinct 13C discrimination.The sum of these results points to the conclusion that the C3 plant Atriplex hortensis can maintain a better internal inorganic nitrogen supply than the C4 plant Amaranthus retroflexus under low N conditions and an ample water supply, due to the larger root proportion and the more pronounced and flexible transpiration of the C3 plant.

Nitrate Reductase Activity of Grain Sorghum Leaves as Related to Yields of Grain, Dry Matter, and Nitrogen1

Eleven grain sorghum (Sorghum bicolor L. Moench) hybrids were grown in the field and growth chamber. Leaf blade samples were assayed by in vitro and in vivo procedures for nitrate reductase activity (NRA) to i)termine NRA of the hybrids, ii) examine relationships between NRA and grain and N yields, and iii) determine whether NRA of growth chamber‐grown plants are indicative of those of field‐grown plants. Among hybrids, differences in yields of grain, dry matter, and grain protein and in in vitro NRA were significant though comparatively small. Seven hybrids had similar N input: accumulation ratios while four had lower ratios. This variation in N input:accumulation ratios, precludes the use of NRA, as assayed here, as a criterion for screening grain sorghum cultivars for N accumulation ability. Also, NRA values of young growth chamber‐grown plants were not indicative of those of field‐grown plants.