Conditions Of Nitrogen Nutrition Research Articles

Biostimulants of growth in the production process of grain crops

The role of biostimulants of growth of various natures in the production process of spring wheat variety Zlata was studied, depending on nitrogen nutrition conditions, and was carried out under field conditions.The experiments assessed the activity of the plant assimilation apparatus and the formation of the yield of wheat plants using biostimulants of various natures by spraying vegetative plants. The studies found that the greatest effectiveness of the studied drugs was observed under conditions of optimal provision of nitrogen nutrition to wheat plants. It has been established that the preparations Epin-Extra, Emistim and Hardy increase the efficiency of the assimilation apparatus of spring wheat plants, which led to the receipt of large increases in grain weight under conditions of optimal provision of wheat plants with nitrogen nutrition.

The relationship of nitrogen nutrition conditions with the productivity of Tamasha potatoes

The article presents the results of three-year (2015-2017) studies research on the influence of nitrogen nutrition conditions on the productivity and quality of potatoes variety Tamasha. The studies were carried out on dark brown heavy loamy carbonate soils of Central Kazakhstan with a humus content of 2.73-2.79 %, total nitrogen - 0.147-0.172 %, total phosphorus - 0.20-0.25 %, with a high level of availability of mobile phosphorus and potassium, low content of nitrate nitrogen, slightly alkaline reaction of soil solution. Studies have shown a high responsiveness of potatoes to nitrogen fertilizers. According to the results of the research, a high correlation between potato productivity and the nitrate nitrogen content in the soil (R=0.85-0.96) was revealed, the optimal level of nitrate nitrogen in the 0-40 cm soil layer was determined for Tamasha potatoes - 17-19 mg/kg. The increased nitrogen content of nitrates in the soil slightly reduced the starchiness of potatoes.

ЖАСЫМЫҚТЫҢ «VICEROY» СОРТЫНЫҢ АЗОТ ТЫҢАЙТҚЫШТАРЫН ЕНГІЗУГЕ ЖАУАП ҚАЙТАРУЫ

The article presents the results of a three-year (2018-2020) study on the biological characteristics of the lentils’ variety “Viceroy”, its relationship to the conditions of nitrogen nutrition and responsiveness to nitrogen fertilizers in the dry steppe zone of Northern Kazakhstan. According to the results of field and laboratory studies, a high correlation was revealed between the productivity of lentils and the nitrogen content of nitrates in the soil (R=0.93; R=0.85), the optimal level of nitrate nitrogen in the 0-40 cm soil layer – 13-15 mg N-NO3 for the Viceroy variety was determined. At this nitrogen level, the highest yield was formed – 27.6 c/ha. Studies have shown that the main reason for the formation of high yields was a change in structural components, namely, the number of pods (from 35.8 to 50.6 pieces) attached to the plant and the weight of seeds (from 1.5 to 2.1 g) from one plant. According to experience, the difference in the average weight of 1000 seeds was obvious in 2018 (39.7 g), in 2019 (33.2 g), in 2020 (32.0 g), however, there were no changes in fertilized variants. With an increase in the amount of nitrogen fertilizers, the nitrogen content in grain increased by 3.45-4.16%, protein by 19.3-23.3%. Bringing the nitrogen content in the soil to the optimal level will allow you to form the maximum possible yield of lentils of the "Viceroy" variety in the prevailing weather conditions.

INFLUENCE OF NITROGEN NUTRITION CONDITIONS AND PHYTHORMONES ON CHANGE OF FATTY ACID COMPOSITION OF VEGETATIVE ORGANS OF SPRING WHEAT TRITICUM AESTIVUM L.

The paper shows the effect of nitrogen nutrition, exogenous auxin, and rhizosphere auxin-synthesizing microorganisms on the variability of the composition of fatty acids (FA) in the vegetative organs of spring wheat. The object of the study was seedlings of spring soft wheat Triticum aestivum L. The determination of FAs was carried out by gas chromatography with mass spectrometry (GC-MS). Analysis of FAs showed that in the control variants (without auxin), nitrogen nutrition conditions did not affect the localization of polyunsaturated FAs in vegetative organs; the maximum content of triene FAs was observed in leaves of 48.30% (N-deficient variant) and 44.8% (NO-3-variant ) and the absence of these FAs in the roots. It was found that in the presence of nitrates, the proportion of unsaturated FAs in the leaves and roots of wheat decreases. The use of exogenous auxin (5–50 μg/ml) in the early stages of ontogenesis leads to an increase in the amount of saturated (palmitic and stearic) acids and a decrease in unsaturated acids in vegetative organs, regardless of the conditions of nitrogen nutrition. During the introduction of spring wheat seedlings by auxin-synthesizing microorganisms, it was noted that nitrogen-fixing bacteria affect the leaves of plants most effectively, the content of saturated FAs increases by 72%, and only 16% increases in these FAs in the leaves of nitrate-reducing microorganisms.

Diversity and function of rhizosphere microorganisms between wild and cultivated medicinal plant Glycyrrhiza uralensis Fisch under different soil conditions.

Glycyrrhiza uralensis Fisch is a widely cultivated traditional Chinese medicine plant. In the present study, culture-independent microbial diversity analysis and functional prediction of rhizosphere microbes associated with wild and cultivated G. uralensis Fisch plant (collected from two locations) were carried. Soil physicochemical parameters were tested to assess their impact on microbial communities. A total of 4428 OTUs belonging to 41 bacterial phyla were identified. In general, cultivated sample sites were dominated by Actinobacteria whereas wild sample sites were dominated by Proteobacteria. The alpha diversity analysis showed the observed species number was higher in cultivated soil samples when compared with wild soil samples. In beta diversity analysis, it was noticed that the weighted-unifrac distance of two cultivated samples was closer although the samples were collected from different regions. Functional annotation based on PICRUST and FAPROTAX showed that the nitrogen metabolism pathway such as nitrate reduction, nitrogen fixation, nitrite ammonification, and nitrite respiration were more abundant in rhizosphere microorganisms of wild G. uralensis Fisch. These results also correlate in redundancy analysis results which show correlation between NO3--N and wild samples, which indicated that nitrogen nutrition conditions might be related to the quality of G. uralensis Fisch.

Efficiency of dung application on rice agroecosystems in Kuban

The effect of the combined application of dung and nitrification inhibitor Entec FL DMPP on the loss of ammonium nitrogen from meadow chernozem soil (corresponding to Gleyic Chernozem in WRB) under the conditions of rice cultivation in the Kuban was studied. On the rice irrigation system, a field experiment was performed with autumn and spring incorporation of dung at a rate of 30 t/ha, both separately and with the addition of a nitrification inhibitor against the background of mineral fertilizers. It was found that the inclusion of a nitrification inhibitor in the dung contributed to a decrease in nitrogen losses by 6.7-15.0% during their incorporation in autumn and by 10.8-18.1% in spring, occurring as a result of denitrification and leaching of nitrates, and optimum conditions of nitrogen nutrition for rice plants. A less pronounced effect of the nitrification inhibitor was noted during its autumn incorporation with dung, which is associated with a lower air temperature in autumn and a longer period from fertilization to rice sowing.

Soils and Nitrogen Nutrition of Plants in Alpine Ecosystems of the Northwest Caucasus under Long-Term Increase in Availability of Biogenic Elements

An experiment with the enrichment of acid organic-rich mountain-meadow soils (Umbric Leptosols) of alpine ecosystems with mineral nutrients has demonstrated that the contents of organic carbon, total nitrogen, and labile organic compounds are stable and tolerant towards long-term (20 years) application of mineral fertilizers. Only the following direct effects are well pronounced: an increase in the content of inorganic nitrogen and phosphorus after the application of corresponding fertilizers, as well as a rise in pH as a result of liming. Plants are more sensitive indicators of changes in the conditions of nitrogen nutrition. They are characterized by active absorption of additional nitrogen, and the isotopic composition of nitrogen in them becomes heavier. The degree of these effects depends on the initial nitrogen availability. In addition to these direct effects, changes in the nitrogen status of plants also reflect changes in the transformation of nitrogen-containing compounds in soil and in the nitrogen nutrition of plants taking place due to an increased availability of phosphorus and lower acidity under the most phosphorus-depleted and most acid conditions, respectively. These impacts lead to the mobilization of soil organic nitrogen and are likely to reduce the role of mycorrhiza in plant nitrogen nutrition. As a result, a heavier isotopic composition of nitrogen is formed in some plant species.

Critical nitrogen dilution curves and nitrogen nutrition diagnosis of spring maize under different precipitation patterns in Weibei dryland

<p indent=0mm>The excessive nitrogen (N) applications, large rainfall variations and poor water-nitrogen couplings are main problems to efficient nitrogen fertilizer uses in spring maize production of Weibei dryland. Critical nitrogen dilution curves under different rainfall scenarios in Weibei dryland were constructed in this study to analyze the feasibilities of diagnosing and evaluating nitrogen nutritional conditions in terms of nitrogen nutrition index (NNI), which would provide a theoretical basis for reasonable nitrogen fertilizations application of dryland maize in response to different rainfalls. The experiment design using Zhengdan 958 (ZD958) and Shaandan 8806 (SD8806) as tested materials was five treatments level, N applied at 0(N0), 75(N1), 150(N2), 270(N3), and 360(N4) kg hm^–2 in 2016 and 2017, and at 0(N0), 90(N0), 180(N2), 270(N3), and 360(N4) kg hm^–2 in 2018 and 2019, respectively. It was rainy at the ear stage and dry at the grain stage in 2016 and 2018, whereas dry at the ear stage and rainy at the grain stage in 2017 and 2019. Critical nitrogen dilution curve models for spring maize with two precipitation patterns were constructed and verified using the data collected in the four-year position nitrogen fertilization experiment. The results showed that: (1) increased nitrogen fertilizer application significantly increased aboveground biomass and plant N concentrations, and there were significantly different among different treatments. Both critical nitrogen concentrations (<italic>N</italic>_c) and aboveground biomass conformed the exponential relations with the two precipitation patterns, but there were differences between the parameters of the models for these relations (a. Rainy at the ear stage: <italic>N</italic>_c = 35.98DM^–0.35; b. Dry at the ear stage: <italic>N</italic>_c = 35.04DM^–0.23). The relatively stable model had a linear correlation between the fitted and actual plant N concentrations, which shown that the RMSE and <italic>n</italic>–RMSE were 1.03 and 5.75% at the ear stage over the rainy years and 1.53 and 6.78% at the ear stage in the dry years, respectively. (2) at the different growth stages, NNI were increased with the increased application, and there were differences in the optimal nitrogen application under different precipitation conditions. The optimum N rate in the form of basal fertilizers was <sc>150–180 kg</sc> hm^–2, and in the form of top dressing fertilizers was <sc>45–75 kg</sc> hm^–2 at the ear stage in the rainy years. The nitrogen nutrition index (NNI) was significantly correlated with relative nitrogen uptake (RN_upt), as were relative aboveground biomass (RDW) and relative yield (RY). When the NNI was 1.02 at the ear stage in the rainy years, the maximum RY was 0.95; and when the NNI was 1.08 at the ear stage in the dry years, the maximum RY was 0.92. The critical nitrogen dilution curve model and nitrogen nutrition index model constructed in this study were able to accurately predict nitrogen nutrition conditions from jointing stage to maturity stage under the two precipitation patterns of spring maize. They would provide an important guidance for nitrogen diagnosis and fertilization application in maize growing stage.

Genetic Variability and Inter-relatedness of Agronomic Traits of Single Cross Hybrid Maize in Contrasting Soil Nitrogen-nutritional Conditions

Background: Lowering the nitrogen demand is the most cost effective and sustainable option to increase grain yield of maize in poor fertility soil.&#x0D; Aim: This study was conducted to estimate the variability and inter-traits’ association of white and yellow hybrid maize in soil nitrogen-nutritional stress and optimal conditions.&#x0D; Materials and Methods: 150 white and 66 yellow single cross hybrid maize were evaluated in contrasting soil (stress and optimal) N conditions in Ibadan in 2014 and 2015. The trial for the white maize was laid out in 19 × 8 lattice design while the yellow maize was experimented in randomized complete block design. Each trial was replicated three times. Data were collected on days to anthesis (DTA), days to silking (DTS), plant height (PH), ear height (EH), anthesis-silking-interval (ASI) and grain yield (GY) were estimated while leaf senescence (LS), plant aspect (PASP) and ear aspect (EASP) were scored. Data collected were subjected to analysis of variance while variances and broad sense heritability were calculated and rated.&#x0D; Results: Greater variability existed among white maize than the yellow maize for the traits. Inheritance of the traits can be predicted in optimal N than stress condition. Additive genes action was responsible for inheritance of DTA and DTS while both additive and non-additive control the GY, PH, EH and LS of the white maize in both N conditions. For yellow maize, the DTA and DTS were controlled by additive genes action in both N conditions. The GY, ASI, PH, EH and LS were governed by both additive and non-additive genes actions in N stress condition. Additive genes action is responsible for inheritance of PH and EH while both additive and non-additive actions govern inheritance of GY, ASI and LS in optimal condition. The GY had positive relationship with the DTA, DTS and LS in both N conditions for the white maize while the GY positively correlated with PH, EH and LS in N stress, but with ASI only in optimal condition for the yellow maize.&#x0D; Conclusion: Grain yield, flowering, height and leaf senescence can be used in selecting maize for nitrogen-use-efficiency.

Response of soybean to nitrogen nutrition conditions and nitrogen fertilizers on soils of dry steppe area of northern Kazakhstan

Response of soybean to nitrogen nutrition conditions and nitrogen fertilizers on soils of dry steppe area of northern Kazakhstan

Genetic basis of nitrogen use efficiency and yield stability across environments in winter rapeseed.

BackgroundNitrogen use efficiency is an important breeding trait that can be modified to improve the sustainability of many crop species used in agriculture. Rapeseed is a major oil crop with low nitrogen use efficiency, making its production highly dependent on nitrogen input. This complex trait is suspected to be sensitive to genotype × environment interactions, especially genotype × nitrogen interactions. Therefore, phenotyping diverse rapeseed populations under a dense network of trials is a powerful approach to study nitrogen use efficiency in this crop. The present study aimed to determine the quantitative trait loci (QTL) associated with yield in winter oilseed rape and to assess the stability of these regions under contrasting nitrogen conditions for the purpose of increasing nitrogen use efficiency.ResultsGenome-wide association studies and linkage analyses were performed on two diversity sets and two doubled-haploid populations. These populations were densely genotyped, and yield-related traits were scored in a multi-environment design including seven French locations, six growing seasons (2009 to 2014) and two nitrogen nutrition levels (optimal versus limited). Very few genotype × nitrogen interactions were detected, and a large proportion of the QTL were stable across nitrogen nutrition conditions. In contrast, strong genotype × trial interactions in which most of the QTL were specific to a single trial were found. To obtain further insight into the QTL × environment interactions, genetic analyses of ecovalence were performed to identify the genomic regions contributing to the genotype × nitrogen and genotype × trial interactions. Fifty-one critical genomic regions contributing to the additive genetic control of yield-associated traits were identified, and the structural organization of these regions in the genome was investigated.ConclusionsOur results demonstrated that the effect of the trial was greater than the effect of nitrogen nutrition levels on seed yield-related traits under our experimental conditions. Nevertheless, critical genomic regions associated with yield that were stable across environments were identified in rapeseed.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-016-0432-z) contains supplementary material, which is available to authorized users.

Physiological efficiency under different nitrogen nutrition conditions and relationship with photosynthetic N-use efficiency in Myanmar local rice varieties (Oryza sativa L.)

Physiological efficiency under different nitrogen nutrition conditions and relationship with photosynthetic N-use efficiency in Myanmar local rice varieties (Oryza sativa L.)

Redox states of photosystems I and II in irradiated leaves of wheat seedlings grown under different conditions of nitrogen nutrition

Changes in the redox states of photosystem I (PSI) and PSII in irradiated wheat leaves were studied after growing seedlings on a nitrogen-free medium or media containing either nitrate or ammonium. The content of P700, the primary electron donor of PSI was quantified using the maximum magnitude of absorbance changes at 830 nm induced by saturating white light. The highest content of P700 in leaves was found for seedlings grown on the ammonium-containing medium, whereas its lowest content was observed on seedlings grown in the presence of nitrate. At all irradiances of actinic light, the smallest accumulation of reduced QA was observed in leaves of ammonium-grown plants. Despite variations in light-response curves of P700 photooxidation and QA photoreduction, the leaves of all plants exposed to different treatments demonstrated similar relationships between steady-state levels of P700+ and QA−. The accumulation of oxidized P700 up to 40% of total P700 content was not accompanied by significant QA photoreduction. At higher extents of P700 photooxidation, a linear relationship was found between the steady-state levels of P700+ and QA−. The leaves of all treatments demonstrated biphasic patterns of the kinetics of P700+ dark reduction after irradiation by far-red light exciting specifically PSI. The halftimes of corresponding kinetic components were found to be 2.6–4 s (fast component) and 17–22 s (slow component). The two components of P700+ dark reduction were related to the existence of two PSI populations with different rates of electron input from stromal reductants. The magnitudes of these components differed for plants grown in the presence of nitrate, on the one hand, and plants grown either in the presence of ammonium or in the absence of nitrogen, on the other hand. This indicates the possible influence of nitrogen nutrition on synthesis of different populations of PSI in wheat leaves. The decrease in far-red light irradiance reduced the relative contribution of the fast component to P700+ reduction. The fast component completely disappeared at low irradiances. This finding indicates that the saturating far-red light must be applied to determine correctly the relative content of each PSI population in wheat leaves.

Photosynthetic CO2Fixation in the Second Leaf of Wheat Seedlings Grown at Different Conditions of Nitrogen Nutrition

The rates of photosynthetic СО2 assimilation were determined in fully expanded second leaves of 21-day-old wheat (Triticum aestivum L.) seedlings grown on media supplied with nitrate or ammonia and on a nitrogen-free medium (NO3 –- or NH4 +-treatments and N-deficit treatment, respectively). The maximal quantum efficiency of photosynthesis was independent on conditions of nitrogen nutrition. When leaves were exposed to 0.03% СО2 and high-intensity light, the lowest photosynthetic rate was noted for N-deficit treatment and the highest rate was characteristic of NH4 + treatment. The elevation of the СО2 concentration in the gas phase to 0.1% stimulated photosynthesis at high-intensity light in all treatments. The rate of СО2 uptake by the leaf of N-deficient seedlings increased with СО2 concentration to a larger extent than in other treatments and approached the СО2 uptake rate characteristic of the NO3 – treatment. In plants grown on a nitrogen-free medium, the leaf accumulated lesser amounts of reduced nitrogen and higher amounts of starch, but the content of chloroplast protein corresponded to that of NO3 – treatment. In the leaf of NH4 +-treated seedlings, the rate of СО2 assimilation was higher than in the leaf of NO3 – treated plants, regardless of the composition of the gas mixture. The ammonium-type nutrition, as compared to the nitrate-type nutrition, elevated the amount of reduced nitrogen in the leaf and promoted accumulation of chlorophyll and protein, the chloroplast protein in particular.

Morphophysiological Indices of the Source Leaf in Wheat Plants Acclimated to Conditions of Nitrogen Nutrition

Growth, leaf and cell morphology, and the chemical composition of the second leaf were studied in wheat (Triticum aestivumL., cv. Inna) plants grown on the medium containing nitrate, ammonium, or no nitrogen at all. Independent of the nitrogen nutrition, the second leaf of the 21-day-old plants matures and functions as a source of assimilates. Both ammonium nutrition and nitrogen deficiency decreased the fresh weight, area, and cell size in the leaf; however, the conditions of nitrogen nutrition did not affect the dry weight of the leaf. Nitrogen starvation increased and ammonium nutrition decreased the relative content of the cell walls in the dry weight. In the nitrate-fed plants, the leaf content of sucrose increased, and the contents of reduced nitrogen (Nred) and protein were lower than in the ammonium treatment. Reciprocally, the contents of reduced nitrogen and protein were highest in the ammonium treatment, the content of sucrose was lowest, with starch practically absent from the leaf. The nitrogen-starved leaf accumulated a large amount of starch, the Nredcontent was two times lower than in the ammonium-fed plants, and the protein content was similar to that in the nitrate-fed plants. Thus, leaf and cell morphology and the content of Nred, protein, and carbohydrate changes in different ways during wheat acclimation to the condition of nitrogen nutrition. By assessing the cell wall weight, the authors established that, depending on nitrogen nutrition, this cell compartment accepts a variable flow of carbon.

Constitutive and nitrogen-regulated promoters of the petH gene encoding ferredoxin:NADP + reductase in the heterocyst-forming cyanobacterium Anabaena sp.

Determination of the putative transcription start points of the petH gene encoding ferredoxin:NADP + reductase in the heterocyst-forming cyanobacteria Anabaena sp. PCC 7119 and PCC 7120 showed that this gene is transcribed from two promoters, one constitutively used under different conditions of nitrogen nutrition and the other one used in cells subjected to nitrogen stepdown and in nitrogen-fixing filaments. The latter promoter, whose use was NtcA-dependent but HetR-independent, was functional in heterocysts. The N-control transcriptional regulator NtcA was observed to bind in vitro to this promoter. For the sake of comparison, the transcription start points of the nifHDK operon in strain PCC 7120 and binding of NtcA to the nifHDK promoter were also examined.

Growth and growth substrate levels in spinach under non-steady state conditions of nitrogen nutrition and light

Growth and growth substrate levels in spinach under non-steady state conditions of nitrogen nutrition and light

Growth and growth substrate levels in spinach under non‐steady state conditions of nitrogen nutrition and light

Spinach plants (Spinacia oleracea L. cv. Subito) were grown in a complete nutrient solution under ample light intensity (14 h day−1 at 660 μmol m−2 s−1) before being transferred either to a minus‐N solution (experiment 1), or to limiting light conditions (6 h day−1 at 220 μmol m−2 s−1; experiment 2). Shoot growth in experiment 1 decreased significantly from 0.24 day−1 to 0.07 day−1 after the fourth day of transfer. Root relative growth rate increased after 1 day from 0.25 to 0.31 day−1, but decreased on the fifth day after transfer to 0.11 day−1. Shoot growth in experiment 2 decreased significantly from 0.25 to 0.17 day−1 after the fourth day of transfer, while root growth decreased to half of its original level (0.25 day−1) already on the second day. Growth substrate levels in the plants (free sugars, free amino acids) and starch levels depended on the plant age, the moment in the diurnal cycle, and the imposed treatment. Fluctuations in shoot growth or root growth resulting from the light or N limitation could not be explained by a correspondent increase or decrease in the levels of growth substrates. The hypotheses underlying the functional equilibrium theory, assuming shoot and root growth to be controlled by N‐ and C‐containing substrates respectively, and several other growth and partitioning models are therefore questioned. A neglect of the osmotic role of the free sugars in these models might be the explanation for this.

Genotype x Bradyrhizobium japonicum strain interactions in dinitrogen fixation and agronomic traits of soybean (Glycine max L. Merr.)

Bradyrhizobium japonicum strain G49 has been the only inoculum used in French soils. Soybean (Glycine max L. Merr.) cultivars were selected and tested according to their performances with this rhizobial strain. The aim of the present study was to determine the consequences of strain substitution on N2 fixation abilities of various genotypes. Three genotypes and cultivar Weber, in combination with B. japonicum strain G49 or SMGS1, were cultivated in pots and tested for nitrogenase activity under differing nitrogen nutrition conditions. The reliability of ARA (acetylene reduction activity) measurement for assessing symbiotic nitrogen fixation under the experimental conditions used was checked. Genotypic variability for symbiotic fixation activity was observed with each strain under soil culture conditions; important genotype x strain interactions were also involved. These results were corroborated for the protein yield and other yield component performances of the various genotype-strain associations. Thus, in France, the replacement of strain G49 with another one might result in the alteration of the relative agronomic performances of the soybean cultivars, since N2 fixation is considered as a major factor of soybean productivity.

Influence of different levels of ammonium concentrations on cell growth, RNA and protein production by Candida albicans.

Candida albicans starved cells were incubated in minimal synthetic liquid media containing different concentrations of ammonium sulphate (0.00, 0.02, 0.05, 0.10, 0.03, 0.50 g/L). Culture growth was monitored by measuring daily the optical density and by evaluating RNA and protein cellular content after 48 and 96 hours from the inoculum. The environmental availability of ammonium ion influenced the biomass production, that was maximum when its concentration was 0.10 and 0.30 g/L. In addition, an effect on cell duplication time was observed, this was particularly evident when the (NH4)2SO4 concentration was 0.10 g/L. The protein content increased in relation to the increase of ammonium ion availability, with a peak in correspondence to 0.30 g/L and a drop when the greatest concentrations were employed. RNA production was inversely proportional in respect to protein production. The optimal range of ammonium sulphate concentration for C. albicans growth was 0.10-0.30 g/L; over these concentrations there was an inhibitory effect. The rate of the protein and RNA syntheses seems to indicate the growth phase and the nitrogen nutritional conditions of the cultures, respectively.