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Microspores were cultured on the modified B₅ liquid medium containing 2.4D (0.1 mg L⁻¹), NAA (0.1 mg L ⁻¹), L-glutamine (500 mg L⁻¹), L-serine (100 mg L⁻¹), and sucrose (100 g L⁻¹). The developmental stages of microspores and divisions were observed. Initially, the formation of binuclear and multicellular structures was noticed. Plants regenerated in the cultures in which the tetrad stage of microsporogenesis had predominated. Embryoids were still forming 24 weeks after the cultures were set up. Six weeks after the transfer of androgenetic embryos onto the B₅ regeneration medium, they were converted into complete plants. Out of 90 androgenetic plants planted in a growth chamber, 42 plants adapted to the new conditions. All of those plants proved to be diploids in cytometric analysis.
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The paper covered with a hydrophobic Topscreen coating was coated with the second layer. The goal of paper covering was to obtain the antimicrobial properties of the external coating. The samples were stored 2 months at 20 ºC. The influence of storage on the antimicrobial properties of the external coating was analyzed. The results of the study showed that paper covered with Topscreen coating did not have an influence on the growth of Staphylococcus aureus cells. The second (external) layer containing 2% polylysine as an active substance decreased the growth of S. aureus. The 2 months storage of the covered paper did not influence the antimicrobial properties of coating with polylysine against S. aureus. It was demonstrated that paper covered with hydrophobic coating had no influence on the growth of E. coli cells as well. In this case the influence of 2 months storage on the antimicrobial properties of the coating with polylysine was observed. In contrast to the results obtained for the samples that were not store, the decrease of the growth of the bacterial cells after 24 h contact with a hydrophobic coating devoid of an active substance was noticed.
The research concerned of the regeneration of plants from embryos obtained from anther cultures of seven carrot (Daucus carota L.) cultivars. The aim was to determine the influence of the regeneration medium on the efficiency of the regeneration process. The optimization of the adaptation of the obtained plants was also carried out. Embryogenesis occurred on four of the tested media: B₅ and MS without hormones, MS with charcoal, and MS with 1 mg dm⁻³ BA and 0.001 mg dm⁻³ NAA. Embryos obtained from the anther cultures produced secondary embryos, from which the regenerations of plants was observed. Secondary embryos were formed most extensively on the B₅ medium without hormones. The efficiency of the regeneration process depended on the cultivar. Most of the secondary embryos were formed by androgenetic embryos of the cultivar ‘Feria F₁’. The highest number of plants (102) regenerated from one embryo during 12 weeks of culture was also obtained in case of the cultivar ‘Feria F₁’. Secondary embryogenesis and plant regeneration from embryos allow to omit the difficult stage of root induction applied when plants are regenerated form shoots’ explants. This makes the plant regeneration process quicker and easier. The plants regenerated by the conversion of embryos are better adapted to the ex vitro conditions than those obtained in the two-stage organogenesis involving the regeneration of shoots and in second stage roots induction.
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Doubled haploid lines of carrot can be obtained through androgenesis in anther cultures and in isolated microspore cultures. The two methods were compared using three carrot cultivars (‘Kazan F1’, ‘Feria F1’, and ‘Narbonne F1’) at the androgenesis induction stage, during plant regeneration from embryos, and during acclimatization of androgenetic plants as well as their characterization. It was found that cultivar was the main factor affecting the efficiency at each stage of plant production in both anther and isolated microspore cultures. The efficiency of androgenesis in anther cultures of ‘Feria F1’ was considerably higher in comparison with isolated microspore cultures, and more plants were obtained from the embryos of androgenesis-cultured plants. In ‘Kazan F1’ and ‘Narbonne F1’, more acclimatized androgenetic plants were produced from anther cultures. Ploidy assessment of acclimatized plants of ‘Narbonne F1’ showed that the majority of the plants in the population derived from anther cultures had a doubled chromosome (DH) set. On the other hand, the majority of plants obtained from isolated microspore cultures were haploids. When assessing homozygosity, it was found among plants obtained in anther cultures that the percentage of homozygotes for phosphoglucose isomerase (PGI) and aspartate aminotransferase (AAT) depended on the cultivar. In contrast, the majority of plants derived from isolated microspore cultures were homozygous regardless of cultivar.
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