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Lavender plants are preferably propagated vegetatively. The aim of the work was to propose the composition of nutrient media for in vitro multiplication of plants of Lavandula angustifolia (var. Krajová and Beta) and Lavandula x intermedia (var. Budrovka and Grosso). Explant cultures were initiated from apical or nodal segments. Apical segments were more suitable and regenerated the highest number of shoots in MS medium supplemented with 1 mg/L BAP with or without 0.1 mg/L IAA in all used varieties. Nodal segments are suitable for var. Budrovka, where the number of shoots was not statistically different between the apical or nodal segments and among the media tested. Shoot multiplication of L. angustifolia varieties was the most effective in the MS media with 0.5 or 1 mg/L BAP. For variety Grosso, the optimal medium was MS with 1 mg/L BAP, while var. Budrovka regenerated a similar number of shoots in all media supplemented with 0.5 or 1 mg/L BAP with or without 0.1 mg/L IAA. All genotypes rooted with the highest frequency on growth regulator-free medium with a half dose of MS salts. After transplanting into the soil and ex vitro acclimatization, plantlets survivability after 10 weeks was 78.9 – 87.7%, except for var. Beta with a lower survivability of 50%. The proposed procedures enable a rapid plant multiplication of varieties Budrovka, Grosso and Krajová. With the Beta variety, it is advisable to continue working on the optimization of nutrient media to verify whether the procedures can be further optimized.

Current problems with sewage sludge (SS) disposal could be solved by application to agricultural land considering its fertilizer properties and ability to improve soil condition. However, SS may contain heavy metals as well as pathogenic microorganisms. In this study, molecular analysis of partial 18S rRNA gene was used to study the impact of SS application into the soil on the genetic diversity of fungal communities, especially arbuscular mycorrhizal fungi in the rhizosphere and roots of barley. These samples were collected on three dates from the control soil without SS and from the soil with the addition of SS at the concentrations of 5 and 15 t ha−1. Fungal alpha diversity in the rhizosphere of barley was affected by SS differently than in barley roots. In addition, principal component analysis and cluster analysis revealed that fungal communities were strongly influenced by the SS addition into the soil, sample type, and the sampling date. This approach was complemented by an evaluation of the basic parameters of barley production and the response of these parameters to the presence of SS in the soil. The plant height increased with increasing SS concentration and the thousand seed weight significantly increased at the concentration of 5 t ha−1 SS but significantly decreased in 15 t ha−1.

The technology of seed coating with superabsorbent polymer (SAP) has the potential to mitigate the negative impact of drought on seed germination and crop establishment. However, their application on the seed surface can affect the effectiveness of pesticides used for seed treatment in the protection against phytopathogens. In our work, the influence of the Aquaholder®Seed polymer coating on the effectiveness of fungicides in the protection of germinating seeds of spring barley cv. Bojos and Laudis against the fungal pathogen Bipolaris sorokiniana was studied. One-half of the seeds were first treated with fungicides, and then a polymer was applied. Fungicide efficacy was evaluated in a Petri dish test and pot test under the pathogen attack. Seed coating with SAP did not negatively affect fungicide efficacy. The percentage of germinated seeds, seedling emergence, plant height, and symptoms of the disease in the fungicide-treated variants were not significantly changed by the SAP application. Moreover, in cv. Laudis, the application of SAP alone partially protected germinating seeds against pathogen attack. The amount of pathogen DNA in plant tissues of cv. Laudis was not significantly different among seed treatments, while in cv. Bojos, the pathogen DNA increased in seeds coated with SAP alone but decreased in combined treatment with fungicides. These results demonstrated that SAP seed coating does not negatively affect the efficacy of fungicides used for seed protection against fungal pathogens. [ABSTRACT FROM AUTHOR]

The aim of our work was to evaluate the effect of selected antibiotics on the growth of potato shoot cultures in the Gene Bank of the Slovak Republic collection and to determine the type and dose that may be used to treat potato cultures endangered by endophytic bacteria. Antibiotics Chloramphenicol at doses 20, 50 and 100 mg/L, Gentamycin and Rifampicin in doses 20, 50, 100, 200 mg/L and the combination of Gentamycin and Rifampicin with 100 mg/L of each were used. Growth parameters – the shoot length and the number of nodal segments per shoot and rooting of ten cultivars of Solanum tuberosum L. of different origin were evaluated. Chloramphenicol already at the lowest dose had the strong inhibitory effect on regeneration, growth, and rooting of shoots. Gentamycin inhibited the growth of shoots gradually with increasing dose of it, rooting of shoots was negatively affected using the dose 50 mg/L or higher. Rifampicin up to 100 mg/L had the minimal effect on the shoots growth, rooting of shoots was not affected, but shoots were characterised by smaller or stunted leaves. Although the growth of shoots was affected, all ten genotypes used in the experiments were able to regenerate and grow at the highest dose of Rifampicin and Gentamycin. According to the results, it is highly probable that these antibiotics up to 100 mg/L or their combination would be suitable for culture preservation of the most genotypes in the gene-bank collection. On the other hand, Chloramphenicol cannot be recommended due to its strong detrimental effect on potato shoot cultures.

Application of sewage sludge to soil is a potentially inexpensive source of nutrition for plants, but may contain undesirable and toxic substances, e.g. heavy metals. Alterations in microbial communities can serve as an environmental indicator of possible soil contamination. We used two molecular fingerprinting methods (Automated Ribosomal Intergenic Spacer Analysis, ARISA and Terminal Restriction Fragment Length Polymorphism, T-RFLP) to study changes in the genetic diversity of bacterial communities in the rhizosphere of Arundo donax L. cultivated in the soil fertilised with additive based on sewage sludge from wastewater treatment plant and agricultural by-products represented by crushed corn hobs and wastes from grain mill industry. The metagenomic DNA extracted from rhizosphere samples were collected in August and November 2014. The amount of mgDNA was statistically higher in samples with additive than in control samples without it in both dates. The Venn diagrams showed that operational taxonomic units which were common to all samples were represented in 32.8% in ARISA and 43.4% in T-RFLP. However, based on Principal component analysis and subsequent PERMANOVA statistical tests did not confirm significant differences in the rhizosphere of control plants and plants grown in the soil supplemented with sewage sludge in dose 5 and 15 t/ha present in the additive.

Wheat is one of three most important cereals worldwide. Its production rises every year. There is a possibility to improve quantitative and qualitative parameters by biolistic method of transformation. The process of introduction of desired gene into the wheat genome and plant regeneration is affected by many factors. To identify the suitable conditions, selection system, the influence of donor, plant environment and the regeneration capacity of wheat genotypes were tested. The scutella of immature embryos served as the initial explants. Plant regeneration was achieved by 6 out of 11 genotypes tested. The highest values were reached by the cultivar Ilias. The effect of donor, plant environment was evaluated by two genotypes. Plants from growth chamber appeared to be better source of explants compared to plants grown in the natural conditions. The selection system was optimized as follows: regeneration medium in the dark and subsequently in photoperiod conditions (DR) with 5 mg/l of phosphinotricin (PPT), shoot induction medium (DS) with 7 mg/l of PPT.

The current findings show that positron emission tomography (PET), primarily developed for medical diagnostic imaging, can be applied in plant studies to analyze the transport and allocation of wide range of compounds labelled with positronemitting radioisotopes. This work is focused on PET analysis of the uptake and transport of 2-deoxy-2-fluoro[18F]-D-glucose (2-[18F]FDG), as a model of photoassimilates, in tissues of giant reed (Arundo donax L. var. versicolor) as a potential energy crop. The absorption of 2-[18F]FDG and its subsequent transport in plant tissues were evaluated in both acropetal and basipetal direction as well. Visualization and quantification of the uptake and transport of 2-[18F]FDG in plants immersed with the root system into a 2-[18F]FDG solution revealed a significant accumulation of 18F radioactivity in the roots. The transport rate in plants was increased in the order of plant exposure through: stem > mechanically damaged root system > intact root system. PET analysis in basipetal direction, when the plant was immersed into the 2-[18F]FDG solution with the cut area of the leaf of whole plant, showed minimal translocation of 2-[18F]FDG into the other plant parts. The PET results were verified by measuring the accumulated radioactivity of 18F by direct gamma-spectrometry.

The effect of plant propagation method on growth parameters and the yield of above-ground biomass in two species of gigantic grasses were measured during three growing seasons. Plants were multiplied in explant culture and through traditional methods – by rhizome segments (Miscanthus × giganteus) or by stem cuttings (Arundo donax). In the case of M. × giganteus, in vitro-multiplied plants produced more shoots with significantly lower diameter, but the differences in the number of shoots, plant height and the yield of dry biomass were not statistically significant. Different results were observed for A. donax, where in vitro-multiplied plants showed significantly weaker results in all parameters, with the exception of the number of shoots in the first measured season. In both the species, there was observed the strong effect of the year. While in M. × giganteus the yield of dry biomass gradually decreased during the measured years, it increased in the case of giant reed.

The aim of the present work was to compare the accumulation and translocation of Cd and Zn in plants of tobacco (Nicotiana tabacum L.), celery (Apium graveolens L.), maize (Zea mays L.), giant reed (Arundo donax L.), and alpine pennycress (Noccaea caerulescens L.) under conditions of short-term hydroponic experiments using nutrient solutions spiked with radionuclides 109Cd or 65Zn, and direct gamma-spectrometry. It was found that the time-course of metals accumulation in studied plants was not different in terms of target metal, but it was significantly different on the level of plant species. The highest values of Cd accumulation showed plants of giant reed, whereby the accumulation decreased in the order: giant reed > tobacco > alpine pennycress >> maize and celery. On the basis of concentration ratios (CR) [Me]shoot / [Me]root calculation for both metals, it was found that Cd and Zn were in prevailing part accumulated in the root tissues and only partially accumulated in the shoots, where the amount of accumulated Cd and Zn increased from the oldest developed leaves to the youngest developed leaves. The CR values corresponding to these facts were calculated in the range 0.06 – 0.27 for Cd and for Zn 0.06 – 0.48. In terms of plant species, the CR values obtained for Cd decreased in the order: maize > celery > tobacco and giant reed > alpine pennycress. The similarity between studied objects – individual plant species on the basis of the obtained variables defining Cd or Zn accumulation at different conditions of the experiments as well as the relationships between obtained variables and conditions of the experiments were subjected to multivariate analysis method – cluster analysis (CA). According to the findings and this analysis, it can be expected that plants of tobacco and giant reed will dispose with similar characteristics as plants of alpine pennycress, which are classified as Zn/Cd hyperaccumulators, in terms of Cd or Zn accumulation and other positive parameters for their utilization in phytoremediation processes and techniques.

The terminal restriction fragment length polymorphism munities from different collecting places was evaluated was used to determine the bacterial diversity in rhizo- by principal component analysis. Results showed that sphere of maize (Zea mays L.) collected from four sites the most different bacterial community originated from of experimental field plot in two dates of the vegetation marginal part of the experimental field plot collected in season (July and September). The 16S rRNA gene was September was caused probably by combination of the amplified from metagenomic DNA using universal eubac- marginal effect and drought before sampling date in Sep- terial primers and PCR products were digested separately tember. Other rhizosphere samples showed from moderate with three restriction enzymes. Significant differences in to small differences in the structure of the bacterial com- the number of terminal restriction fragments among rhi- munity. Nevertheless, significant differences among all zosphere samples and between sampling dates were not collected bacterial communities were not observed. detected (P < 0.05). Variation within the bacterial communities from different collecting places was evaluated by principal component analysis. Results showed that the most different bacterial community originated from marginal part of the experimental field plot collected in September was caused probably by combination of the marginal effect and drought before sampling date in September. Other rhizosphere samples showed from moderate to small differences in the structure of the bacterial community. Nevertheless, significant differences among all collected bacterial communities were not observed.

The in vitro cell cultures of Vitis vinifera L. cv. St. Laurent were treated with two elicitors - synthetic methyl jasmonate and natural, prepared from grapevine plant infected with the Phaeomoniella chlamydospora, the agent causing the Esca disease of grapevine. Efficiency of phenolic compounds production after elicitation of cell culture was analysed immediately after treatment (15 min, 30 min, 60 min) and later (after 24, 48, and 72 hours). The cell growth and content of phenolic compounds (+)-catechin, (-)-epicatechin, p-coumaric acid, syringaldehyde, rutin, vanillic acid, and trans-resveratrol were analysed in cultivated cells as well as in cultivation medium. Pch-treatment increased production of total polyphenols the most significantly 15 min after the elicitation and in optimal time was 2.86 times higher than in nonelicited culture and 1.44 times higher than in MeJa induced cell culture.

In vitro regeneration ability of modern agronomically important spring barley cultivars and winter wheat cultivars grown in Slovakia was screened and compared with the model cultivars Golden Promise for barley and Bobwhite for wheat. Immature scutella of ten cultivars of barley and four cultivars of wheat were used as a starting tissue for the establishment of in vitro culture. To induce callogenesis in barley, Dicamba was used in the nutrient medium, while 2,4-D in combination with BAP was used for induction of regeneration. For wheat 2,4-D was used for calogenesis initiation and regeneration was induced on media without hormone added. The aim of experiment was to select local regenerable cultivars suitable for following transformation experiments. Frequency of callogenesis and regeneration, and number of regenerants were evaluated. All tested barley cultivars showed significantly lower regeneration ability in comparison with Golden Promise. Nevertheless cultivars Levan and Pribina, reaching sufficient results in all evaluated parameters, could be recommended for following experiments. Results obtained from four wheat cultivars showed a very good regeneration ability of genotype CY-45 in comparison with model genotype Bobwhite. [ABSTRACT FROM AUTHOR]

Superabsorbent polymers (SAPs) applied to soil have been recognized as water reservoirs that allow plants to cope with periods of drought. Their application as a seed coat makes water available directly to the seeds during their germination and early growth phase, but on the other hand, it can affect the efficiency of plant protection substances used in seed dressing. In our experiments, we evaluated the effect of seed coating with SAP on fungicide leaching and changes in their effectiveness in suppressing Fusarium culmorum infestation. Leaching of fungicide from wheat seeds coated with SAP after fungicide dressing, as measured by the inhibition test of mycelium growth under in vitro conditions, was reduced by 14.2–15.8% compared to seeds without SAP coating. Germination of maize seeds and growth of juvenile plants in artificially infected soil did not differ significantly between seeds dressed with fungicide alone and seeds treated with SAP and fungicide. In addition, plants from the seeds coated with SAP alone grew significantly better compared to untreated seeds. Real-time PCR also confirmed this trend by measuring the amount of pathogen DNA in plant tissue. Winter wheat was less tolerant to F. culmorum infection and without fungicide dressing, the seeds were unable to germinate under strong pathogen attack. In the case of milder infection, similar results were observed as in the case of maize seeds. [ABSTRACT FROM AUTHOR]