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Zawartość Fe, Mn, Zn, Cu, Ni, Pb i Cd w poszczególnych organach mniszka pospolitego (Taraxacum officinale) zebranego z pól odłogowanych leżących na obszarze ekologicznie „czystym” w otulinie Roztoczańskiego Parku Narodowego była wyraźnie zróżnicowana. W mniszku pospolitym zawartość tych pierwiastków układała się w następujący malejący szereg: Fe > Zn > Mn > Cu > Pb > Ni > Cd. Poszczególne części mniszka pospolitego akumulują różne zawartości tego samego pierwiastka śladowego. Żelazo było akumulowane w dużych ilościach przez korzenie i liście, mangan przez łodygi i korzenie, miedź przez kwiatostany i korzenie, cynk przez nasiona i kwiatostany, a nikiel i kadm nie wykazują dużego zróżnicowania ilościowego w poszczególnych organach.
The gas chromatography–mass spectrometry (GC–MS) analysis of essential oil obtained by hydrodistillation from the flower of Taraxacum officinale L. revealed the presence of 25 compounds with 1,3-dimethylbenzene, 1,2-dimethylbenzene, 1-ethyl-3-methylbenzene, heneicosane and tricosane as the main components.
Badania połowę prowadzono w latach 2000 - 2002 na glebie płowej o składzie granulometrycznym piasku gliniastego mocnego, metodą split-plot, w czterech powtórzeniach, na poletkach o powierzchni 10 m². Czynnikiem pierwszego rzędu był sposób zakładania plantacji (siew nasion wprost do gruntu i wysadzanie rozsady). Czynnikiem drugiego rzędu było dokarmianie dolistne dwoma nawozami (Ekolist S i Rolvit-B). Na podstawie uzyskanych wyników stwierdzono, że mniszek uprawiany z rozsady daje istotnie większy plon korzeni i liści. Dokarmianie dolistne wpłynęło korzystnie na plonowanie oraz modyfikowało zawartość Cu i Zn w korzeniach i liściach mniszka pospolitego. Liście w porównaniu z korzeniami charakteryzowały się wyraźnie wyższą zawartością badanych mikroelementów (Cu, Zn, Mn i Fe).
The study concerned PCB accumulation in soil at two depths (S1: 0-20 cm, S2: 20- 40 cm) and in Taraxacum officinale plants. It was carried out within railway junctions and near railway lines. Various degrees of PCB contamination were detected in soil and parts of plants above the ground level. PCB content in most soil samples was between 100 and 250 ng/g, while in plants it varied from 100 to 800 ng/g. An analysis of the distribution of different groups of PCB congeners in plant and soil material has revealed that the content of hepta-CB and hexa-CB fractions was the highest of all PCBs for both soil depths, as well as for plants. No significant differences were found for the degree of various PCB congener group penetration into the soil, neither in railway junction areas, nor in the vicinity of railway tracks. Statistical test of pair comparison, performed in order to establish the rate at which plants accumulate different groups of PCB congeners has revealed significant differences in accumulation rates for the following pairs: penta-chlorinated congeners are accumulated at a higher rate than tetra-chlorinated ones and hexa-chlorinated congeners are accumulated at a higher rate than penta-chlorinated ones. This phenomenon occurs in the area of railway junctions (areas heavily polluted with oil derivatives). It was found that in the area of railway lines (areas with low levels of pollution) hexa-chlorinated congeners were accumulated at a higher rate than tetra- and penta-chlorinated ones. No significant differences were found for other pairs of PCB congeners. The use of dandelion as a bioindicator of environmental pollution with PCB congeners seems to be a good and reliable source of information about the emission of those substances into the natural environment.
The common dandelion (Taraxacum officinale F.H. Wigg) is a perennial plant often found in large concentrations in the sward of natural meadows. This species expands quickly, displacing other species. In literature there is a lack of data relating to the effect of common dandelion on plants growing in its vicinity. It is also not known why this species creates large clusters. Perhaps it competes with different plants through the allelopathic effect. Hence, the aim of this study was to determine the influence of water extracts from leaves and roots of common dandelion (Taraxacum officinale) as well as soil extracts from the root layer of this species on seed germination and the initial growth of Lolium westerwoldicum R.Br. The investigated material comprised leaves and roots of Taraxacum officinale. The germination biotest most often used in experiments was applied. The seeds germination energy of westerwolds ryegrass was most inhibited by plant extracts prepared from roots and leaves of Taraxacum officinale. The germination ability of seeds of Lolium westerwoldicum was the highest in the treatments in which soil extracts were applied; however, the value of this feature was limited to a larger extent by the plant extracts from leaves of Taraxacum officinale than from roots. Higher concentrations of both soil and plant solutions had an inhibitory effect both on root growth and the growth of the leaf sheath and leaves of westerwolds ryegrass. The results of the tested parameters can confirm the allelopathic effect of Taraxacum officinale on germination and initial growth of Lolium westerwoldicum, and especially that of extracts prepared from leaves.
The aim of this study was to explain how temperature, desiccation, light and nitrate affect the seasonal pattern of germination and persistence of dandelion achenes. Directly after collection, Taraxacum officinale Web. ex Wiggers achenes were characterized by non-deep primary dormancy, while dry stored at a low temperature, they showed slight seasonal variations of dormancy level. Both high and low soil temperatures caused dormancy release in dandelion seeds. Dandelion achenes did not form a persistent soil bank. The decline of viable seeds was probably due to long-term sub-zero soil temperatures accompanied by its considerable hydration. Nitrate may be a component of the system of environmental signals which, along with light and desiccation, would enable dandelion seeds to detect even the smallest gaps in dense vegetation. As the dormancy changes are fast, the detection of these gaps by Taraxacum officinale achenes may be especially effective. Such ability of dandelion seeds may explain the remarkable ease with which this species occupies grassland areas densely covered with vegetation.
Dandelion (Taraxacnn officinale) was used in a KBN-supported project focused on the assessment of the extent to which Polish agricultural environment is contaminated with sulphur. Studies were carried out in different regions of the country. Sulphur content in leaves ofthat plant at full blooming varied with the level of sulphur contamination of soil and air. Dandelions from the heavily industrialised areas of the Upper Silesia, Legnica-Głogów Copper Mining District, and the Tarnobrzeg Sulphur Mining District showed high sulphur content and the S content (0.4%) in excess of the threshold value for this species.
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