Ivana Maksimović

Steady presence of cadmium and nickel affects root anatomy, accumulation and distribution of essential ions in maize seedlings

When growing in the field, plants are exposed to the effect of heavy metals as soon as the seed comes into contact with the soil solution. Therefore, we found important to study the effect of Cd and Ni on maize exposed to these heavy metals since sowing. The aim of this work was to examine which anatomical changes are induced by continuous intoxication of young maize root system with 0.1 mM Cd and Ni, thus modifying its growth and capacity for water and nutrient uptake. Concomitantly, the effect on concentration and distribution of Cd, Ni and some essential ions (Ca, Mg, Zn, Fe, Cu and Mn) was studied.

Unexploited potential of some biotechnological techniques for biofertilizer production and formulation

The massive application of chemical fertilizers to support crop production has resulted in soil, water, and air pollution at a global scale. In the same time, this situation escalated consumers’ concerns regarding quality and safety of food production which, due to increase of fertilizer prices, have provoked corresponding price increase of food products. It is widely accepted that the only solution is to boost exploitation of plant-beneficial microorganisms which in conditions of undisturbed soils play a key role in increasing the availability of minerals that otherwise are inaccessible to plants. This review paper is focused on the employment of microbial inoculants and their production and formulation. Special attention is given to biotechniques that are not fully exploited as tools for biofertilizer manufacturing such as microbial co-cultivation and co-immobilization. Another emerging area includes biotechnological production and combined usage of microorganisms/active natural compounds (biostimulants) such as plant extracts and exudates, compost extracts, and products like strigolactones, which improve not only plant growth and development but also plant-microbial interactions. The most important potential and novel strategies in this field are presented as well as the tendencies that will be developed in the near future.

Effect of yttrium on photosynthesis and water relations in young maize plants

Abstract Despite an increase in spectrum of industrial applications of yttrium (Y) and the fact that it is widely present in the soils and plants, some of which are agronomically important crops, its effects on plant growth and metabolism are still obscure. Therefore, the aim of this work was to examine the effect of different concentrations of Y on its accumulation and distribution, photosynthetic responses, water relations, free proline concentration and growth of young maize plants. The experiment was done with maize ( Zea mays L., hybrid NS-640), in water cultures, under semi-controlled conditions of a greenhouse. Plants were supplied with half-strength complete Hoagland nutrient solution, to which was added either 0 (control), 10 −5 , 10 −4 or 10 −3 mol/L Y, in the form of Y(NO) 3 ·5H 2 O. Each variant was set in thirteen replications, with six plants in each replication. Plants were grown for 21 d and they were at the stage of 3 and 4 leaves when they were analyzed. The presence of Y reduced maize growth and photosynthetic performance. Dimensions of stomata significantly decreased while their density significantly increased on both adaxial and abaxial epidermis. Plant height, root length, total leaf area and dry mass also declined. Concentration of photosynthetic pigments (chl a and b and carotenoids) and free proline decreased. Photosynthesis and transpiration were impaired in the presence of Y – their intensities were also reduced, and the same stands for stomatal conductance of water vapor, photosynthetic water use efficiency (WUE) and water content. Although the highest concentration of Y was found in maize roots in each treatment, Y concentration in the second leaf and shoot also significantly increased with an increase in Y concentration in the nutrient solution. Albeit Y concentration was much higher in roots than in shoots, shoot metabolism and growth were much more disrupted. The results demonstrated that young maize plants accumulated significant amount of Y and that this element, when present in higher concentrations, had unfavorable effect on physiological processes and therefore plant growth.

Growth, ion composition, and stomatal conductance of peas exposed to salinity

Availability of irrigation water of appropriate quality is becoming critical in many regions. Excess salt in irrigation water represents a risk for crop yield, crop quality, and soil properties. During the short vegetation period, field peas require high amounts of water, and irrigation is often indispensable for successful production. Steady presence of NaCl (0.1, 0.2, 0.6 or 1.2 g NaCl L−1 in 1/2 strength Hoagland nutrient solution) under semi-controlled conditions reduced growth and resulted in shorter vegetation. Disturbances in the peas’ water regime were provoked by NaCl, as water content in pea tissues was reduced and stomatal density and stomatal diffusive resistance increased in the presence of higher NaCl concentrations. Concentration of Na+ increased in all pea tissues with increased NaCl concentration in the nutrient medium. In the presence of NaCl, concentrations of K+, Ca2+ and Pi increased in roots, stems and leaves, and decreased and in pods and grains. Concentration ratios Na+/K+, Na+/Ca2+, K+/Ca2+ and (Na++K+)/Ca2+ in various plant parts were affected as well, but magnitudes of changes were variable. Continuous presence of NaCl in concentrations frequently met in irrigation waters significantly reduced pea growth, impaired the water regime, and altered plant chemical composition.

Potential application of glycerol in the production of plant beneficial microorganisms

This review highlights the importance of research for development of biofertilizer and biocontrol products based on the use of glycerol for further process scale-up to industrial microbiology. Glycerol can be used successfully in all stages of production of plant beneficial microorganisms. It serves as an excellent substrate in both submerged and solid-state fermentation processes with free and immobilized microbial cells. Glycerol is also one of the most attractive formulation agents that ensures high cell density and viability including in harsh environmental conditions. Future research is discussed to make this inexpensive material a base for industrial production of plant beneficial microorganisms.

The effect of imidazolium based ionic liquids on wheat and barley germination and growth: Influence of length and oxygen functionalization of alkyl side chain

In this work five different imidazolium based ionic liquids, namely: 1-(2-oxybutyl)-3-methylimidazolium chloride, [C2OC2mIm][Cl]; 1-(2-oxypropyl)-3-methylimidazolium chloride, [C1OC2mIm][Cl]; 1-(3-hydroxypropyl)-3-ethylimidazolium chloride, [OHC3eIm][Cl]; 1-(3-hydroxypropyl)-3-methylimidazolium chloride, [OHC3mIm][Cl]; 1-(2-hydroxyethyl)-3-methylimidazolium chloride, [OHC2mIm][Cl], together with commercial 1-butyl-3-methylimidazolium chloride, [bmim][Cl] and synthesized protic imidazolium chloride, [Im][Cl], were prepared and their toxicity examined towards wheat and barley germination and growth. Introduction of the polar groups (in the form of hydroxyde and/or ether group) in the alkyl side chain of the imidazolium cation and their influence on the reduction of the ionic liquids toxicity is demonstrated. The results indicate that toxicity of oxygen functionalized ILs is significantly lower against wheat comparing to non-functionalized analogues. In the case of barley, influence on germination follow the same trend as in the case of wheat, but for seedlings growth different trend is observed with more pronounced toxicity of ether functionalized ILs. From these results it was also shown that alkylation in the position N-3 atom of the imidazole significantly reduces toxicity of cation.

Effects of Heavy Metals on Chemical Composition of Camelina sativa L.

Camelina ( Camelina sativa L.) is studied mostly as oil plant that can replace oilseed rape in the extensive agriculture. It is a good source of oil (40% oil in seeds) similar to sunflower, soybeans, canola, castor been and other oil crops. Oil of camelina is rich in essential omega 3 fatty acids. In addition, seed protein content is relatively high. Camelina has modest requirements for agro-ecological conditions and it is highly resistant to pathogens. Those features make camelina suitable for human nutrition and animal feed. Its use is related to sustainable agriculture, bio-diesel industry, cold-pressed oils and the use of so-called marginal land. Examination of its ability to uptake and accumulate heavy metals (HM) is interesting from the standpoint of 1) food safety and 2) potential for phytoremediation. Hence, the aim of this study was to investigate the effect of HM on uptake and accumulation of some essential macro- and micronutrients and unwanted HM. Experiments were done with Camelina sativa L., cultivar Stepski 1. The seeds were exposed to 1 µM Cd or Cu and 10 µM Ni or Zn since the beginning of germination. Plants were grown in water cultures, in semi-controlled conditions of a greenhouse, on ½ strength Hoagland solution to which were added HM in the same concentrations as during germination. Concentrations and distribution of Ca, Mg, P, K, Fe and Mn in roots and shoots were altered in the presence of increased concentration of Cd, Cu, Ni and Zn.

Effects of Salinity on Vegetable Growth and Nutrients Uptake

Irrigation of vegetables during both air and soil-born drought has very positive effect on growth, development and yield. The impact of irrigation on the metabolism of plants is very complex because the increase in soil moisture affects plant physical, chemical and biological properties. Increasing the amount of water in the soil increases its heath capacity. Irrigated (wet) soil is cooler in summer and warmer during the cold weather in comparison with dry soil. Irrigation increases heat conduction in soil and relative humidity of ground layers of the atmosphere. These changes reduce the temperature fluctuations of ground layers of the air and soil during the day and night. Therefore, irrigation suppresses harmful effects of the weak spring and autumn frosts. The water in the soil acts as a solvent and as an environment in which chemical reactions take place. With increasing soil moisture concentration of soil solution is diminishing and the power of water to dissolve different substances is increasing. The CO2 dissolved in the water contributes significantly to this process by lowering the pH value of soil solution. In weak acidic solution mineral elements present in the soil become more soluble, which may alter plant nutrition. However, if there is any excess of water in the soil, than easily soluble salts of potassium, nitrogen and phosphorus from the upper layers of soil can be leached into deeper soil layers, even outside the zone of the root system, which is very undesirable. In general, irrigation increases soil pH, which should be borne in mind because optimum acidity (pH) for cultivation of most vegetables is between 6.0 and 6.5. Irrigation has a positive effect on microbial processes in the soil which in turn affects nutrient availability to plants. Moreover, irrigation stimulates aerobic processes that may be temporarily slowed down or replaced by anaerobic if the soil is too wet.

BORON CONCENTRATION VS. CONTENT AS CRITERION FOR ESTIMATING BORON TOLERANCE IN WHEAT

The objective of this study was to investigate the relationships among boron (B) concentration, boron content, and tolerance to excess boron in 40 wheat (Triticum aestivum L.) genotypes. Boron tolerance was estimated at seedling stage by filter paper technique, imposing three boron treatments (50, 100 and 150 mg L−1 boric acid, H3BO3) and comparing the response of root length and dry weight to the control (0.93 mg L−1 H3BO3). Although substantial variation in boron tolerance, concentration, and content has been found among the studied wheat genotypes, regression analysis showed no relationship between neither root length reduction and boron concentration, nor dry weight reduction and boron concentration. On the other hand, a positive linear relationship was found between boron content and both root length and dry weight response to high external boron; tolerant wheat genotypes were characterized by higher boron content than the sensitive ones. The results may be explained by significant decline of root length and dry weight in sensitive genotypes, which caused reduced uptake of all nutrients, including boron. Vice versa, root length and dry weight of tolerant genotypes were affected by boron treatments to the smaller extent, allowing the uptake of higher amounts of boron and resulting in comparatively high boron content.

Essential (Cu and Zn) and trace (Pb and Cd) heavy metal loads in onion and potato

Heavy metals are one of many pollutants that can be found on the surface and in tissue of fresh vegetables. Therefore, the aim of this paper was to assess and analyse concentrations of essential (Cu and Zn) and trace (Pb and Cd) heavy metals in onion ( Allium cepa L.) and potato ( Solanum tuberosum L.) produced in Vojvodina. The concentration of Cu, Zn, Pb and Cd was determined in edible plant parts, onion bulbs and potato tubers by atomic absorption spectrophotometry. In only two samples of onion and four samples of potato, the concentration of Cd was above the limit set by regulations of the Republic of Serbia.