Odnos koncentracije zemnoalkalnih metala kalcijuma, barijuma i stroncijuma u zrnu diploidne, tetraploidne i heksaploidne pšenice

Even though calcium (Ca), strontium (Sr) and barium (Ba) belong to the same group of the periodic table of elements, and thus have similar chemical features, their importance for plants differs greatly. Since plants do not have the ability to completely discriminate between essential (e.g. Ca) and non-essential elements (e.g. Sr and Ba), they readily take all of them up from soil solution, which is reflected in the ratios of concentrations of those elements in plant tissues, and it influences their nutritive characteristics. The ability of plant species and genotypes to take up and accumulate chemical elements in their different tissues is related to their genetic background. However, differences in chemical composition are the least reflected in their reproductive parts. Hence, the aim of this study was to evaluate ratios of concentrations of Ca, Sr and Ba in the whole grain of diploid and tetraploid wheat ‒ ancestors of common wheat, as well as in hexaploid commercial cultivars, grown in the field, at the same location, over a period of three years. The investigated genotypes accumulated Ca, Sr and Ba at different levels, which is reflected in the ratio of their concentrations in the grain. The lowest ratio was established between Ba and Sr, followed by Ca and Ba, while the highest ratio was between Ca and Sr. Moreover, the results have shown that the year of study, genotype and the combination highly significantly affected the ratio of the concentration Ca:Sr, Ca:Ba, and Ba:Sr.Kalcijum (Ca), stroncijum (Sr) i barijum (Ba) pripadaju istoj grupi elemenata Periodnog sistema i imaju slične hemijske osobine. Međutim, njihove uloge u biljnom organizmu veoma se razlikuju. Obzirom da biljke nemaju sposobnost da u potpunosti razlikuju esencijalne (C a) od neesencijalnih elemenata (Sr i B a), one ih sve usvajaju iz zemljišnog rastvora, a to se odražava u različitom odnosu koncentracija ovih elemenata u biljnom tkivu i utiče na njihove nutritivne osobine. Sposobnost vrsta i genotipova da usvajaju i akumuliraju hemijske elemente u različitim tkivima, zavisi od njihove genetike. I pored toga, razlike u hemijskom sastavu ogledaju se u njihovoj reproduktivnoj ulozi. Cilj istraživanja bio je da se odrede odnosi koncentracija Ca, Sr i Ba u celom zrnu diploidne i tetraploidne pšenice - pretka današnje pšenice, kao i heksaploidnih komercijalnih vrsta, gajenih na istom polju i lokalitetu tokom tri godine. Ispitivani genotipovi su akumulirali Ca, Sr i Ba u različitim količinama, što se odrazilo na odnos njihovih koncentracija u zrnu. Najniži odnos ustanovljen je između Ba i Sr, zatim Ca i Ba, a najveći između Ca i Sr. Takođe, rezultati su pokazali da godina ispitivanja , genotip i kombinacija značajno utiču na odnos koncentracije Ca:Sr, Ca:Ba i B a:Sr

Primena modifikovanih tanina u antikorozionim alkidnim premazima

The study of the synthesis of anticorrosive inhibitors, based on chemically modified tannins, and their use in alkyd based coatings to improve anticorrosive properties is presented in this work. Two methods of tannin modification were applied: direct method using ammonium hydroxide, ammonium hydroxide/ammonium chloride buffer or diethylenetriamine (DETA); and a two-step method including tannin modification with epichlorohydrin (ECH) in first step to produce epoxy modified tannin, ET, and further modification with heteroaromatic amines or linseed oil fatty acids (LFA) in second step. The obtained anticorrosive additives were characterized using ATR-FTIR, 1H and 13C NMR spectroscopies and elemental analysis. Epoxy, amino, hydroxyl, acid and iodine values of the synthesized inhibitors were determined according to standard methods. The prepared alkyd coating with tannin inhibitors was tested according to standard SRPS EN ISO 4628 method. Anticorrosive coating containing modified tannin based additive showed increased anticorrosive properties, good adhesion and coverage comparing to the coating with zinc phosphate additive. The alkyd coating films based on ET-LFA and ET modified with 2-amino-5- mercapto-1,3,4-thiadiazole showed best anticorrosive results.U ovom radu prikazana je sinteza antikorozionih aditiva na bazi hemijski modifikovanog tanina i njihova primena u alkidnim premazima u cilju poboljšanja antikorozionih svojstava. Prikazane su dve metode modifikacije tanina: direktna modifikacija tanina primenom amonijum-hidroksida, amonijum-hidroksid/amonijum-hlorid pufera ili dietilentriamina (DETA); i dvostepena modifikacija tanina koja u prvom stupnju uključuje modifikaciju epihlorhidrinom sa ciljem da se dobije tannin sa epoksi terminiranim funkcionalnim grupama, ET, i modifikaciju ET tanina sa heteroaromatičnim aminima ili masnim kiselinama izolovanim iz lanenog ulja (LFA) u drugom stupnju. Sintetisani antikorozioni aditivi su okarakterisani primenom ATR-FTIR, 1H i 13C NMR spektroskopija, i elementalnom analizom. Sadržaj epoksi, amino, hidroksilnih i karboksilnih grupa i vrednost jodnog broja sintetisanih aditiva određen je prema standardnim metodama. Alkidni premazi koji sadrže antikorozione aditive na bazi modifikovanog tanina ispitani su prema standardnoj SRPS EN ISO 4628 metodi. Antikorozivni alkidni premazi na bazi modfikovanih tanina pokazali su poboljšane antikorozione karakteristike i adheziju u poređenju sa alkidnim premazom na bazi cink-fosfata. Alkidni premazi koji sadrže dvostepeno modifikovani tanin sa LFA i 2-amino-5-merkapto-1,3,4-tiadiazolom pokazali su najbolje antikorozione karakteristike

Effect of low concentrations of NaCl on accumulation and distribution of Na, K, Ca and their ratios in different plant species

Uneven distribution of precipitations during vegetative season, periods of drought, inappropriate quality of irrigation waters and particularities of soil composition are the main factors leading to salinization of agricultural soils. The area of salt-affected soils is increasing worldwide, leading to yield losses and deterioration of plant-derived food and feed. To assess the extent to which the steady presence of sodium chloride in relatively low concentrations (0.1-1.2 g L-1) affects plants, an experiment was set in semi-controlled conditions of a greenhouse. Safflower (Carthamus tinctorius L., Asteraceae), coriander (Coriandrum sativum L., Apiaceae) and oilseed rape (Brassica napus L., Brassicaceae) were grown in water cultures, on halfstrength Hoagland’s nutrient solution, to which NaCl was added 2 weeks after planting. Plant growth, ash content, accumulation and distribution of Na in relation to K and Ca were analyzed 3 weeks following the beginning of the treatment

Spectral reflectance indices as a phenotyping tool for assessing morpho-physiological traits of winter wheat (Triticum aestivum L.)

Morpho-physiological traits of wheat such as a grain weight per plant, total leaf chlorophyll content, carotenoids, relative dry matter and nitrogen content are important traits for the growth of winter wheat genotypes. However, methods to estimate these traits are laborious and destructive. Spectral reflectance indices based on combination of visible and near-infrared wavelengths such as NDVI (Normalized Difference Vegetation Index), represent one of the most promising tools for application in field phenotyping with potential to provide complex information on different morpho-physiological traits of wheat. The aim of this study was to assess the utility of NDVI measurements of wheat canopy in identification of a specific growth stage in which remotely sensed data show the largest correlation with final grain yield, grain weight per plant, total leaf chlorophyll and carotenoid content, relative dry matter and nitrogen content in 29 winter wheat (Triticum aestivum L.) genotypes. The NDVI was measured using an active hand-held sensor GreenSeeker (NTech Industries Inc., Ukiah, California, USA) and hyperspectral camera (Ximea Corp., Lakewood, CO USA) at four growth stages of wheat: full flowering (BBCH 65), medium milk (BBCH 75), early dough (BBCH 83) and fully ripe stage (BBCH 89). Overall 66 different hyperspectral NDVIs were calculated from two-band combinations between red (600-700 nm) or far red (700-740 nm) and near-infrared (756-946 nm) regions. Pearson’s correlation coefficient was used to explore the relationship among examined traits and NDVI measured at different growth stages of wheat. Obtained results indicate that most of observed NDVI indices showed negative correlation with the relative dry matter content at all observed growth stages. Significant positive correlations (higher than 0.6 and significant at P < 0.05) were found between the specific hyperspectral NDVIs measured at medium milk stage and grain weight per plant, total leaf chlorophyll, carotenoid and nitrogen content, as well as with final grain yield of wheat. The strong positive relationship between NDVI and examined traits found at medium milk stage suggests that this stage is the most appropriate for estimation of these traits of winter wheat in semiarid or similar wheat growing conditions. The overall results indicate that spectral reflectance tools based on combined visible and near-infrared wavelengths, such as NDVI, could be successfully applied to assess morpho-physiological traits of a large number of winter wheat genotypes in a rapid and non-destructive manner. Furthermore, although neither device appeared to have a sizeable advantage over the other, NDVI acquired by hyperspectral camera does appear to be more indicative than NDVI acquired by GreenSeeker sensor, suggesting that alternative spectral combinations can be used in assessing targeted traits of winter wheat genotypes. Abstract boo

Physiological and chemical characteristics of safflower (Carthamus tinctorius L.) grown in the presence of low salt concentrations

(Carthamus tinctorius L.) is highly regarded in the world as an aromatic, spicy, medicinal and oilseed crop, which can be used in all kinds of industries. It inhabits arid and semiarid areas of the world. The influence of the relatively low NaCl concentrations found in soils and irrigation waters on the growth and metabolism of saf­flower, grown under semi-controlled conditions, was examined in this work. It was found that increased concentrations of NaCl affected the number of leaves per plant and dry leaves mass/area ratio. The transpiration intensity was reduced in plants grown in the presence of NaCl and stomatal diffusive resistance increased following an increase in NaCl concentration

The predicted impact of climate change on maize production in Northern Serbia

The projected climate change is expected to have detrimental impact on agricultural production in Northern Serbia, which imposes the need to develop mitigation strategies that will provide a stable yield and income of growing plants in the coming years. Maize is the most important crop in Serbia which occupies the largest sown area. In the present study, the aim was to determine how the average yield of rainfed maize will change in near future (2001-2030) relative to the present and if the currently or higher irrigation rate can be used as a strategy to mitigate the effect of predicted weather scenario on maize yield. AquaCrop model was calibrated with the data derived from the field experiment with rainfed and irrigated maize (2015-2018) (relative standard error ≤ 5% in rainfed and ≤ 7.3% in the irrigated trial), which was used for the simulation of maize yield. The results of the validation showed very good performance of the model (root mean square error of 0.22 and 0.16 was obtained for rainfed and irrigated maize, respectively). The model predicts the loss of maize yield of 15% with respect to maize yield from the experiment. In the predicted scenario, irrigation with average irrigation rate of 200 mm applied in the region of Northern Serbia is expected to increase the yield of maize by approximately 28%. Increased irrigation rate (250 and 300 mm) will reduce the yield of maize in comparison to the current one, thus the creation of stable maize hybrids with the increased water use efficiency should be considered as a strategy for alleviating climate change effect on maize production in the near future.

Biomass production and mineral composition of coriander (Coriandrum sativum L.) exposed to NaCl

The presence of excessive salts in the soil and irrigation water can change the growth and affect the metabolic functions of plants. Coriander (Coriandrum sativum L.) is often cultivated in arid and semiarid areas where irrigation with low-quality water and uneven distribution of rainfall may contribute to the accumulation of salts in the substrate. In the present study, coriander plants were cultivated in half-strength Hoagland nutrient solution containing 0.2, 0.6 and 1.2 g NaCl L−1 to assess the effect of low concentrations of NaCl on biomass production and mineral nutrients accumulation (Ca, K, Mg, Na, P). The presence of 0.2, 0.6 and 1.2 g NaCl L−1 slightly stimulated biomass production. The concentration of Na increased in coriander tissues (up to 4 times relative to control). However, concentration of K and Ca in leaves of plants treated with 1.2 g NaCl L−1 was decreased with respect to control. Based on the findings, even though biomass of coriander, under applied NaCl concentrations, was slightly increased, the chemical composition of its vegetative organs was severely disrupted by present salt which is very important for the quality of coriander as a popular herb or spice plant

Innovative environmentally friendly technology for copper(II) hydroxide production

The innovative laboratory procedure for the synthesis of copper(II) hydroxide in the form of the aqueous suspension was developed. The reaction mechanism consists of the reaction between copper(II) sulphate pentahydrate and sodium carbonate by successive ion exchange of carbonate ions with the hydroxide ones in a multistep process. Production of copper(II) carbonate and sodium sulphate by reacting of copper(II) sulphate with sodium carbonate was followed by addition of sodium hydroxide solution whereby the product, copper(II) hydroxide, was obtained by releasing an equimolar amount of sodium carbonate. It was determined that, the equimolar reaction of copper(II) sulphate and sodium hydroxide lead to the maximal reactants exploitation. Sodium phosphate, formed in the final process stage by addition of 10% phosphoric acid solution, acted as a copper(II) hydroxide stabilizer. High yield of the product was obtained by optimizing the synthesis parameters: reaction time, molar ratio of reactants and the reaction temperature. The obtained product was formulated to obtain a commercial product, which is used as a fungicide and bactericide

The concentration ratio of alkaline earth elements calcium, barium and strontium in grains of diploid, tetraploid and hexaploid wheat

Even though calcium (Ca), strontium (Sr) and barium (Ba) belong to the same group of the periodic table of elements, and thus have similar chemical features, their importance for plants differs greatly. Since plants do not have the ability to completely dis­criminate between essential (e.g. Ca) and non-essential elements (e.g. Sr and Ba), they read­ily take all of them up from soil solution, which is reflected in the ratios of concentrations of those elements in plant tissues, and it influences their nutritive characteristics. The ability of plant species and genotypes to take up and accumulate chemical elements in their different tissues is related to their genetic background. However, differences in chemical composition are the least reflected in their reproductive parts. Hence, the aim of this study was to evaluate ratios of concentrations of Ca, Sr and Ba in the whole grain of diploid and tetraploid wheat - ancestors of common wheat, as well as in hexaploid commercial cultivars, grown in the field, at the same location, over a period of three years. The investigated genotypes accumulated Ca, Sr and Ba at different levels, which is reflected in the ratio of their concentrations in the grain. The lowest ratio was established between Ba and Sr, followed by Ca and Ba, while the highest ratio was between Ca and Sr. Moreover, the results have shown that the year of study, genotype and the combination highly significantly affected the ratio of the concentration Ca:Sr, Ca:Ba, and Ba:Sr