The role of foliar application of aminoacids on the development of barley in conditions of soil contamination with cadmium

Foliar application of nitrogen can increase readily assimilable nitrogen in grapes without increasing vegetative growth and yield. Recently, nano-formulations have been used to achieve a controlled and precise release of agrochemicals, avoiding losses due to degradation and volatilisation that could cause environmental problems. In this study, foliar urea treatments were applied to Monastrell grapevines in two different formats during three consecutive seasons. The treatments were administered at veraison and one week later, consisting of control, urea, and calcium phosphate nanoparticles doped with urea. The amino acids and ammonium contents were subsequently quantified in both grapes and resulting wines by HPLC-DAD. The results in the grapes depended on the season: in 2019, both treatments produced an increase in total nitrogen content; in 2020, only the nano-treatment caused it; in 2021, both treatments incremented nitrogen content. With regard to the effect on the wines, the results also depended on the season. Thus, in 2019 and 2020, there were increases in nitrogen content in the wines from the nano-treatments, in contrast to 2021 where the increase was in the urea treatment. In conclusion, both treatments can be used to prevent nitrogen deficiency in grapes and guarantee adequate fermentation development, with the additional economic and environmental advantages of nano-treatment due to the lower dosage.

Based on the previous paper (Osaki et al. 1995, Soil Sci. Plant Nutr., 41, 635-647), crops were classified by root characteristics for nitrogen uptake as follows: Group I (small root dry weight (RW) and high specific absorption rate of nitrogen (SARN)): legumes, potato, and beet; group II (large RW and low SARN): cereals; and group III (large RW and high SARN): sunflower. In the roots of field crops subjected to various treatments in a field of Hokkaido University, the nitrogen, calcium, and magnesium contents in roots were relatively higher in group I than in groups II and III. Potassium content in roots was high in maize and sunflower. Phosphorus content in roots in groups I and II increased linearly with the increase of the nitrogen content, and the contents of both minerals were higher in group II than in group I. However, the phosphorus content in group III remained constant or increased slightly with the increase of the nitrogen content. Potassium content in roots in groups I and II did not change with the increase of the nitrogen content up to a value of about 20 mg g−1 then it increased slightly with the increase of the nitrogen content above a value of about 20 mg g−1, especially in group I. Potassium content in roots in group III was constant regardless of nitrogen content. Calcium and magnesium contents were not related to the nitrogen content in groups I and II, but increased with the increase of the nitrogen content in group III. SARN increased exponentially with the increase of the nitrogen content in the roots of groups I and II. In group I, the values of SARN were generally higher than in group II for a similar nitrogen content, while in group III, SARN increased linearly with the increase of nitrogen content in roots. Consequently, it appears that nitrogen and phosphorus nutrition in roots is very important for the maintenance of root activity (SARN).

Creation of plant-based bioregenerative life support systems is crucial for future long-duration space exploring missions. Microgravity is one of the major stresses affecting plant growth and development under space flight conditions. Search for higher plant genotypes resilient to microgravity as well as revealing of biological features which could be used as markers of such resilience is rather urgently needed. The objective of this study was to analyze physiological and biochemical responses of three orchid species representing different life forms (terrestrial and epiphytic), growth types (monopodial and sympodial) and pathways of CO2 fixation to long-term (24 months) clinorotation which modeled the combined effect of two stress factors: hermetic conditions and microgravity. Three years old meristematic orchids Cypripedium flavum, Angraecum eburneum, Epidendrum radicans, representing different life forms, types of branching shoot system and pathways of CO2 fixation, were used as test-plants. The microgravity was simulated using three-dimensional (3-D) clinostat equipped with two rotation axes placed at right angles (rotation frequency was 3 rpm) in controlled conditions of air temperature, illumination, air humidity and substrate moisture. The control plants were grown in the similar plastic vessels but not hermetically sealed and without clinorotating in the same environmental conditions. The vital state of the test plants was assessed using characteristics of mineral nutrition, content of photosynthetic pigments, free amino acids, soluble proteins, DNA and RNA, enzymatic and non-enzymatic antioxidants. The results of this study confirmed that orchids grown under simulated microgravity and kept in hermetically-sealed vessels were subjected to oxidative stress, which could be responsible for the observed inhibition of basic physiological processes such as mineral nutrition, metabolism of aminoacids, protein biosynthesis and photosynthesis. Monopodial orchids C. flavum and A. eburneum demonstrated better adaptation to prolonged clinorotation as compared to sympodial E. radicans. In particular, the latter demonstrated some stimulation of mineral nutrition processes (i.e. K, N, Fe, Mn, Zn accumulation), content of photosynthetic pigments, proline and superoxide dismutase activity. Long-lasting clinorotation induced adaptive changes of antioxidant systems in the studied orchids (e.i. increase in carotenoids and proline content and stimulation of superoxide dismutase activity), which helped to maintain the main physiological functions at stable level in the above-mentioned stressful conditions. The following biochemical characteristics in the studied orchids could be considered as markers of resilience to simulated microgravity and hermetic conditions: 1) an increase in the accumulation of non-enzymatic (proline, carotenoids) and enzymatic antioxidants (superoxide dismutase); 2) ability to maintain stable balance of mineral nutrients; 3) increase in the content of photosynthetic pigments; 4) increase in the content of proteinogenic amino acids and soluble proteins; 5) increase in the DNA content or RNA/DNA ratio. Our studies have also demonstrated a correlation between orchid ecomorphological characteristics such as type of branching with their adaptive responses to prolonged clinorotation. We observed no correlation between the studied life form of orchids, ecotype or the pathway of CO2 fixation and their resilience to prolonged clinorotation. This research can be a starting point for studying the relationships between ecomorphological features of various orchids and their resilience to microgravity conditions in the search for biological markers of microgravity tolerance in species of higher plants.

Creation of plant-based bioregenerative life support systems is crucial for future long-duration space exploring missions. Microgravity is one of the major stresses affecting plant growth and development under space flight conditions. Search for higher plant genotypes resilient to microgravity as well as revealing of biological features which could be used as markers of such resilience is rather urgently needed. The objective of this study was to analyze physiological and biochemical responses of three orchid species representing different life forms (terrestrial and epiphytic), growth types (monopodial and sympodial) and pathways of CO2 fixation to long-term (24 months) clinorotation which modeled the combined effect of two stress factors: hermetic conditions and microgravity. Three years old meristematic orchids Cypripedium flavum, Angraecum eburneum, Epidendrum radicans, representing different life forms, types of branching shoot system and pathways of CO2 fixation, were used as test-plants. The microgravity was simulated using three-dimensional (3-D) clinostat equipped with two rotation axes placed at right angles (rotation frequency was 3 rpm) in controlled conditions of air temperature, illumination, air humidity and substrate moisture. The control plants were grown in the similar plastic vessels but not hermetically sealed and without clinorotating in the same environmental conditions. The vital state of the test plants was assessed using characteristics of mineral nutrition, content of photosynthetic pigments, free amino acids, soluble proteins, DNA and RNA, enzymatic and non-enzymatic antioxidants. The results of this study confirmed that orchids grown under simulated microgravity and kept in hermetically-sealed vessels were subjected to oxidative stress, which could be responsible for the observed inhibition of basic physiological processes such as mineral nutrition, metabolism of aminoacids, protein biosynthesis and photosynthesis. Monopodial orchids C. flavum and A. eburneum demonstrated better adaptation to prolonged clinorotation as compared to sympodial E. radicans. In particular, the latter demonstrated some stimulation of mineral nutrition processes (i.e. K, N, Fe, Mn, Zn accumulation), content of photosynthetic pigments, proline and superoxide dismutase activity. Long-lasting clinorotation induced adaptive changes of antioxidant systems in the studied orchids (e.i. increase in carotenoids and proline content and stimulation of superoxide dismutase activity), which helped to maintain the main physiological functions at stable level in the above-mentioned stressful conditions. The following biochemical characteristics in the studied orchids could be considered as markers of resilience to simulated microgravity and hermetic conditions: 1) an increase in the accumulation of non-enzymatic (proline, carotenoids) and enzymatic antioxidants (superoxide dismutase); 2) ability to maintain stable balance of mineral nutrients; 3) increase in the content of photosynthetic pigments; 4) increase in the content of proteinogenic amino acids and soluble proteins; 5) increase in the DNA content or RNA/DNA ratio. Our studies have also demonstrated a correlation between orchid ecomorphological characteristics such as type of branching with their adaptive responses to prolonged clinorotation. We observed no correlation between the studied life form of orchids, ecotype or the pathway of CO2 fixation and their resilience to prolonged clinorotation. This research can be a starting point for studying the relationships between ecomorphological features of various orchids and their resilience to microgravity conditions in the search for biological markers of microgravity tolerance in species of higher plants.

This study was carried out to investigate the effect of storage time and growth regulator, Furolan on protein, non-protein nitrogen and nitrogen contents of three varieties of winter wheat grains namely Batko, Diya and Krasnodar 99. The contents of the nitrogen, protein and non-protein nitrogen in winter wheat grain were determined by different protocols during the full ripeness phase of the grain and the period of 12 months storage. The grains (both the control and experimental) were kept in storage for varied periods under normal conditions. Krasnodar 99 variety responded most to the Furolan and recorded an increase in protein nitrogen content by 46.3% followed by 24.9% in experimental Batko variety and 17.4% in Diya’s variety in comparison with the control. The content of protein nitrogen in the grain of experimental Batko variety increased up to the seventh month of storage, and then decreased by the 12th month of storage. In the control—a similar tendency of change in this parameter was observed. It was noted that seven months of storage is critical in change dynamics of the content of non-protein nitrogen in the selected winter wheat varieties studied.

The results of the studies on the formation of quantitative and qualitative composition of protein in millet of different varieties depending on meteorological conditions during the growing season and separate phases of vegetation are presented. The research was conducted in 2018-2020 in the Samara region on three samples of common millet groats: Povolzhskoe 80 (middle-early), Krestyanka and Rossiyanka (medium-maturing). Correlation dependence of protein and essential amino acids content between the sum of active temperatures and precipitation was revealed. Meteorological conditions of the experimental years can be characterized as unfavorable, arid, with uneven distribution of precipitation (HTC 0.52–0.54). A positive strong relationship was observed between the sum of active temperatures and protein content (r = 0.74-0.98, d = 60.8-96.0 %) in the phase of sprouting – full ripeness depending on the variety. The correlation of precipitation with protein content showed a strong negative relationship on all the varieties (r = –0,70 … –0.99, d = 49,0–96,0 %). Increased temperature regime and precipitation deficit contributed to the increase in the percentage of protein content in millet groats of the studied varieties. Lower temperatures and increased precipitation cause a decrease in protein accumulation. The first deficient limiting amino acid, by which the biological value of protein is estimated, is lysine with the highest value of 20.75 % in the variety Povolzhskoe 80. The increase in lysine content in all the studied varieties is significantly influenced by the temperature regime in July in the phase of tillering – ear formation (r = 0,73–0,99).

The effects of boron and niacin deficiency and excess on the growth of carrot (Daucus carota L. cv. nantes) individually and together was investigated. The seeds of plant sowed directly to lacking boron, and 6 mg/l boron (0) and 0,5 mg/l nicotinic acid (control, K), and 31 mg/l (5B) boron, and also lacking niasin (nicotinic acid)(0N), 2,5 mg/l (5N), and finally 31 mg/l boron and 2,5 mg/l niacin together (5B/5N) containing Murashige-Skoog nutrient medium. Root-shoot length and IAA hormone and pigment (chlorophyll and carotenoid) content were determined in the germinated seeds eight weeks old plantlets. According to the results, either boron or niacin lacking or excess boron or excess niacin in the medium, did not effect germination rate. On the other hand, boron deficiency caused an increase in root length and IAA content and an increase in pigment content; while the excess boron and excess niacin caused a decrease in root length and IAA content but an increase in shoot length and a decrease in pigment content, at the end of eight week. In contrary, niacin deficiency caused a decrease in root length and shoot length and pigment content, but an excess increse in IAA content. We obtained roots and shoots of carrot plant in an approximately equal length when we grew them in the medium which added excess boron (five times more) and excess niacin (five times more) together, and this medium also caused an increase with the highest value in IAA content and pigment and carotenoid content of carrot plant in comparison to the other mediums. So we can propose to be used niacin towards the toxic effects of boron.

This research, conducted over two consecutive years in the production fields of the Iceberg Lettuce Centar in Belgrade, aimed to investigate the impact of biostimulants on the morphological and phytochemical characteristics of iceberg lettuce in two seasons (spring and autumn), using greenhouse and open field cultivation. The biostimulator was derived from a seaweed (Kelpak). The effects of different applications (seedling soaking and foliar treatment once, twice, and three times during the growing season) on plant growth (total plant mass, leaf mass, and stem mass) and phytochemical properties, including pigments (chlorophyll a, chlorophyll b, carotenoids), as well as antioxidant activity (TAC, polyphenols), were investigated. The results showed that the application of biostimulators, particularly through the seedling soaking method, contributed to an increase in plant mass and greater biomass accumulation, whereas foliar treatments enabled better development in both seasons. Plants grown in the greenhouse had more stable growth and better quality, while the spring season proved to be more favourable than autumn. Biostimulators also had a positive effect on the content of photosynthetic pigments and antioxidants, which improved the nutritional value and stress resistance of plants.

Activity of Photosynthetic Enzymes in Leaves of Maize (Zea mays L.) Seedlings in Relation to Genotype and to Temperature Changes

The effect of carbon and nitrogen contents on the grain boundary reaction has been investigated in steels with a base composition of 21%Cr-4%Ni-9%Mn-bal.Fe. In steels containing about 0.9 wt% of carbon plus nitrogen, the increase in nitrogen content enhanced remarkably the grain boundary reaction and suppressed the intragranular precipitation, while the increase in carbon content gave an opposite effect and enhanced the precipitation in the matrix. In steels containing various amounts of carbon and nitrogen, increase in both nitrogen and carbon contents enhanced the reaction, but nitrogen was much more effective than carbon. The nodules of the reaction were observed in steels containing more than 0.5 wt% nitrogen even though no carbon was added, but they could not be detected in steels containing less than 0.1 wt% nitrogen no matter how high the carbon content of steels was.The effect of other alloying elements has also been investigated in a commercial 21-4N steel. They were classified in three groups. Only 0.5 wt% addition of Nb suppressed considerably the reaction and enhanced the intragranular precipitation which caused a decrease in supersaturation of carbon plus nitrogen in the matrix and an increase in pinning force. Both Mo and W had the same effect as Nb and therefore 1 wt% of Mo or W was effective to suppress the reaction. The grain boundary reaction was also suppressed by 13 wt% of Mn or 0.5 wt% of Cu which raised the solubility of carbon plus nitrogen in the matrix. A very small addition of B was effective to suppress strongly the reaction.

The development of fuel cells is hampered by the sluggish oxygen reduction reaction (ORR), which is responsible for high overpotentials, even on Pt-based electrocatalysts. Therefore, it is mandatory the search for more active materials and, at the same time, composed by earth-abundant elements for attaining the widespread commercialization of the fuel cell systems. Non-noble metal electrocatalysts based on iron, nitrogen and carbon composites have gained considerable attention mainly due to recent discoveries of two different active structures: (i) nitrogen-coordinated iron-carbon materials (represented here by Fe-N-C), in which the active center contains the nitrogen-iron coordination and; (ii) nitrogen-doped carbon-encapsulated iron nanoparticles (Fe@N-C), in which the electrocatalyst is formed by iron nanoparticles protected by a graphitic shell of carbon layers, doped with nitrogen atoms [1,2]. In the present study, non-noble metal electrocatalysts composed by iron, nitrogen and carbon were synthesized by the pyrolysis of a mixture of Vulcan carbon, iron chloride and a nitrogen precursor in N2 atmosphere. The results showed that when the pyrolysis was conducted at 700 oC, the use of imidazole as the nitrogen precursor resulted in the formation of the encapsulated nanoparticle structure, as revealed by the presence of a peak at ca. 2.1 Å (metallic Fe nanoparticles) in the Fourier Transform (FT) of the EXAFS oscillations. On the other hand, when phenanthroline was used as the nitrogen precursor, a FT peak centered by ca. 1.5 Å was obtained, evidencing the formation of the nitrogen-iron coordinated structure. When the pyrolysis was conducted at 1050 oC, the resulting structure was the same for the case of imidazole, but a mixture of Fe@N-C and Fe-N-C was obtained for phenanthroline. The ORR polarization curves for the materials prepared at 700 oC showed much higher activity for the Fe-N-C structure, but with similar and low stability for both materials. The pyrolysis at 1050 oC also showed higher activity for the material prepared with phenanthroline, but the stability was considerably improved, with similar behavior for both electrocatalysts. An additional pyrolysis step at 950 oC in NH3 atmosphere resulted in an increased ORR activity and stability for both electrocatalysts, but still with much higher activity for the Fe-N-C-containing material. Interestingly, the EXAFS results showed that the prolonged NH3 treatment of the Fe@N-C structure conducted to the appearance of the FT peak at 1.5 Å (nitrogen-iron coordination), and the ORR polarization curves indicated further increase on its original activity and stability. These results evidenced that the increase in the overall nitrogen content of the electrocatalyst by using a efficient iron chelating agent (phenanthroline), or via NH3 treatment, improved the ORR activity due to the increase in the iron-nitrogen interaction for both Fe-N-C and Fe@N-C initial structures. (Further enhancement in the ORR activity may come from the increase in the nitrogen doping level of the graphitic matrix). The increase in the nitrogen content for both Fe-N-C and Fe@N-C structures may promote a more embraced carbon matrix and, so, it may avoid the demetallation phenomenon, increasing the stability during the ORR. [1] U.Tylus, Q. Jia, K. Strickland, N. Ramaswamy, A. Serov, P. Atanassov, S. Mukerjee, J. Phys. Chem. C 2014, 118, 8999−9008. [2] K. Strickland, E. Miner, Q. Jia, U. Tylus, N. Ramaswamy, W. Liang, M-T. Sougrati, F. Jaouen, S. Mukerjee, Nat. Commun. 6:7343 (2015) 1-7. Acknowledgements The authors gratefully acknowledge financial support from FAPESP (2013/16930-7, and 2016/13323-0) and CNPq.

The effect of the long-term use of soil tillage systems on the elements of potential fertility and agrochemical properties of dark-grey forest soil was determined. The research was conducted in the Northern Trans-Urals in a stationary experiment in the grain-fallow crop rotation: bare fallow - winter rye - spring wheat - grain legumes - spring barley, developed in time and space. Upon completion of the 5th rotation (2008-2012), the effect of moldboard, non-moldboard, combined, differential, subsoil and surface tillage systems on soil fertility was studied. It was established that various systems of the basic tillage carried out during five rotations of the grain-fallow crop rotation did not have a significant effect on the soil acidity. Non-moldboard and differential soil tillage, as well as plowing had an equal effect on the content of the total absorbed bases. Annual minor tillage, like sub-soil and disk harrowing led to the decrease in the content of the total absorbed bases by 13-29% in the layer of 2040 cm. The use of non-moldboard tillage caused the decrease in the content of gross nitrogen and gross phosphorus; nitrogen - by 0.70 t/ha in the topsoil, and by 1.33 t/ha or by 10-24% in the soil layer of 2040 cm; phosphorus - by 0.30 t/ha and by 0.27 t/ha or 18-23%, respectively, compared to moldboard tillage. Combined tillage with alternating plowing and non-moldboard soil loosening to a depth of 20-22 cm contributed to the increase in the gross nitrogen content by 1.05 t/ha in the 0-20 cm layer, and by 0.41 t/ha or by 8-45% in the soil layer of 20-40 cm, and led to the increase in the content of mobile phosphorus by 0.23 t / ha or by 14% in the topsoil, compared to the moldboard tillage system. All tillage systems had almost equal effect on the content of gross nitrogen in the soil. Tillage systems with the elements of minimization contributed to a slight increase in the total phosphorus content by 6-14% in the soil layer of 0-20 cm. Resource-saving tillage systems did not affect adversely the content of gross potassium forms in the soil layer of 0-40 cm.

Fructan and antioxidant metabolisms in plants of Lolium perenne under drought are modulated by exogenous nitric oxide

Flooded soils usually consist of a surface aerobic phase a few millimeters thick (in contact with the atmosphere or oxygenated solution) underlain by an anaerobic phase. The objective of this research was to study nitrogen fixation in the aerobic-anaerobic interfacial area in flooded, cellulose enriched media and the utilization of the products of anaerobic decomposition of cellulose by nitrogen-fixing organisms when these products are brought under aerobic conditions by processes such as diffusion, mixing, and drying. The medium used for these studies was basically a sand matrix supplemented with a small amount of soil and mineral nutrients. When columns of medium enriched with cellulose were sectioned after incubation in the dark under flooded conditions, the increase in content of nitrogen per gram medium in the top 2 to 3 mm of the column was as much as 10 to 15 times the increase in nitrogen content of the lower portions of the column. Periodic mixing of flooded media, alternation of shaking in nitrogen and air atmospheres, and alternate flooding and drying all enhanced fixation relative to undisturbed, continuously flooded media incubated in air. Fixation during incubation under a nitrogen atmosphere was less than fixation under air atmospheres. The results of numerous experiments are consistent with the hypothesis that nitrogen fixation is enhanced when the products of anaerobic decomposition of cellulose are brought under aerobic conditions by any of several processes.

Radish is a root vegetable of the Brassicaceae family that is grown and eaten all over the world. It is often consumed raw as a crisp salad vegetable with a strong flavor. Therefore, this study aimed to clarify the stimulating effect of different γ-rays dose levels (0.0, 10, 20, 40, and 80 Gy) on the quality properties of radish, in addition to its nutritional elements, as well as some of the metabolites found in the red radish roots. The results indicated that the irradiated seeds showed a high germination rate of ≥96% for dose levels of ≤20 Gray (Gy). In addition, the use of gamma rays had a stimulating effect on the vegetative growth, particularly at the doses of 10 and 40 Gy, which provided the largest values of plant height (32.65 cm) and leaf number/plant (8.08), respectively, whereas all the irradiation treatments led to a rise in the length and width of leaves. However, the maximum root characteristics (length, diameter, size, and weight) were confirmed at the dose of 20 Gy (17.51 cm, 5.45 cm, 85.25 cm3 as well as 78.12 g, respectively). It was also noted that the content of plant pigments was significantly higher at a dose of 20 Gy. Additionally, there was an increase in the content of vitamin C using gamma rays, and the highest content (19.62 mg/100 g FW) was at the dose of 20 Gy. The use of γ-radiation caused an increase in some metabolite contents, such as anthocyanin, phenols, and flavonoids, which resulted in an enhancement in the antioxidant activity, achieving the greatest value at the dose of 40 Gy. Exposure of red radish seeds to gamma irradiation before cultivation improved the root contents of the elements (N, K, S, P, Ca, and Mg). The results indicated an increase in the content of organic acids (oxalic, succinic, and glutaric acids) using the radiation dose of 20 Gy, except for malic acid, which had the highest value at a dose of 80 Gy. Similarly, the amino acid pool was significantly increased by irradiation, and the levels of amino acids, which act as originators of the glucosinolate (GLS) phenylalanine, tyrosine and methionine), increased after exposure to gamma radiation, especially at doses of 40 and 80 Gy. Therefore, the red radish roots produced from seeds exposed to gamma rays were of high quality and nutritional value compared to those obtained from un-irradiated seeds. For this reason, gamma-rays are one of the tools that are utilized to improve the growth and quality of crops, especially in low doses.