Micropropagated plantlets derived from selected clones of the hybrid aspen (Populus tremula × Populus tremuloides) and the rowan-tree (Sorbus aucuparia L.) were used to determine the comparative study of uptake of the toxic, heavy metals Cd, Pb and the essential metal Mn. Samples of roots and aboveground parts (hypocotyl-derived tissues, leaves and stems) were taken from the plantlets grown for 24, 48, 96, or 168 hrs under aseptic conditions, in hydroponics with the toxic heavy metal and the essential metal salts. The concentration and distribution of the accumulated metals were determined using the ICP-OES method. The differences in the uptake capacity of hybrid aspen and rowan-tree clones for Cd, Pb and Mn were identified. Generally, the amounts of accumulated Cd and particularly Pb were much higher in the roots of both hybrid aspen and rowan-tree clones, than in their shoots, at all sample times. Conversely, the amounts of accumulated Mn were significantly lower than Cd and Pb in all plant parts of the hybrid aspen and rowan-tree samples. Patterns of Mn uptake were similar in the above-mentioned tissues of both clones, at all sample times. We concluded that the two clones of hybrid aspen and rowan-tree, lacking auxiliary soil microbiota, can accumulate large amounts of the toxic heavy metals Cd (800-1,500 mg/kg) and Pb (5,000-13,000 mg/kg) in roots and about 100 mg/kg of Cd was determined in aboveground part of hybrid aspen.

(18)Information on public attitudes towards the use of transgenic trees in forest plantations is important in the decision-making process and policy implementation for safe tree development, particularly at the EU level. In Europe, the use of transgenic forest trees is very limited and therefore such information is completely lacking. To address this issue within the FP0905 European COST Action on the Biosafety of Transgenic Forest Trees a pioneer cross-country pilot survey on public attitudes towards the use of transgenic forest trees was conducted using young population as a focus group. This was decided mainly because this focus group represents the future consumers, policy makers or developers. Specifically, the survey aimed to: i) assess the level of young people's knowledge about transgenic forest trees, ii) identify issues of concern to them regarding the cultivation of transgenic forest trees and iii) explore whether they approve or disapprove of the use of transgenic forest trees in plantations. Purposive sampling was performed and university students of different disciplines were included in the research as sampling subjects. In total, 1868 completed questionnaires from 15 European and nonEuropean countries were analyzed. The young educated people that took part in the survey appeared to approve of the use of transgenic forest trees in plantations and would be willing to buy forest transgenic products. The potential loss of biodiversity due to a risk of gene flow between transgenic and wild trees was seen as the safety issue of most concern when considering the commercial release of transgenic forest trees. However, a serious perceived lack of knowledge about potential benefits and risks of the cultivation of transgenic forest trees was recorded in most of the countries. K-means clustering was implemented on respondents' positive responses to identify potential country patterns. No differences in patterns of public attitude towards the acceptance of the commercial growing of transgenic forest trees were observed between European and non-European countries. Extended research on public attitude issues towards the use of transgenic forest trees is strongly recommended as a basis for policy implementation on safe tree development.

We have compared the influence of two aromatic cytokinin derivatives, N 6 -benzyladenine (BA) and meta-topolin (mT), on the in vitro multiplication and senescence of wych elm (Ulmus glabra Huds.). After 3 months of cultivation, the micropropagation rate was higher (approx. six times more shoots developed) on Murashige and Skoog (MS) medium supplemented with mT than on MS supplemented with BA. Quantification of 50 endogenous cytokinins, using a recently developed UPLC-ESI(+)-MS/MS method, showed significant differences in the cytokinin metabolites (especially different glucosides) in explants cultivated on media supplemented with BA or mT. Differences in efficiency of photosystem II was also detected.

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