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951.
The arbuscular mycorrhizal status of two plant species, Biscutella laevigata L. and Plantago lanceolata L., was investigated on calamine spoil mounds in Boles^aw (southern Poland). Although B. laevigata is a member of the Brassicaceae, a family generally accepted as non-mycorrhizal, this species formed AM symbioses on both heavy metal-contaminated and non-contaminated sites. Besides vesicles and coils, arbuscules were also observed, especially in roots collected prior to seed maturity. Relative mycorrhizal root length and relative arbuscular richness were usually much higher in P. lanceolata than in B. laevigata but not absolute arbuscule richness. Roots of P. lanceolata showed higher colonisation than B. laevigata. Although roots were collected from plants in close proximity, no correlation in mycorrhizal parameters was found between the two species. 相似文献
952.
Ruth C. Martin David W. S. Mok Rafaël Smets Harry A. Van Onckelen Machteld C. Mok 《In vitro cellular & developmental biology. Plant》2001,37(3):354-360
Summary Zeatin and its derivatives are major consituents of higher plant cytokinins. Metabolic steps modifying the isoprenoid side
chain, such as O-glycosylation, are expected to have a direct bearing on cytokinin-mediated processes. To examine this possibility,
transgenic tobacco plants were generated harboring a gene (ZOG1) encoding a zeatin O-glucosyltransferase from Phaseolus lunatus under the control of a constitutive (35S) and an inducible (Tet) promoter. The presence of the transgene resulted in elevated
enzyme production and conversion of exogenous zeatin to its O-glucoside, confirming the expression of the ZOG1 gene in transgenic plants. Endogenous O-glucosylzeatin was increased from less than 1 pmol per g fresh weight in leaves and roots of controls to 26 and 68 pmol per
g fresh weight in leaves and roots of 35S-ZOG1 transformants, respectively. In cytokinin/auxin interaction experiments, Tet-ZOG1 leaf discs, in the presence of tetracycline, required 10-fold higher zeatin concentrations for the formation of shoots and
callus than the controls. In 35S-ZOG1 plants, developmental changes included adventitious root formation on the lower stems, shorter stature, and axillary shoot
growth. Thus, increased zeatin O-glucosylation in detached, cytokinin-dependent tissues leads to a shift in the response to
exogenous zeatin indicative of cytokinin sequestering. In whole plants the effect can simulate a reduction or a rise in cytokinin
activity depending on the tissue and stage of development. The use of tissue- and stagespecific promoters in the future will
allow more precise analyses and targeted growth alterations. 相似文献
953.
Agnieszka Fischer Danuta Wiechuła Lidia Postek-Stefańska Jerzy Kwapuliński 《Biological trace element research》2009,132(1-3):19-26
The study shows the results of research on the concentrations of metals (Cd, Pb, Mn, Cu, Cr, Fe, Zn, Na, K, Mg, and Ca) in deciduous and permanent teeth with respect to their location in the oral cavity (maxilla, mandible). It has been found that the concentrations of metals were significantly higher in the deciduous teeth than in permanent ones. Regression analysis and principal component analysis revealed an increased dynamics of the processes of binding the elements by the hydroxyapatite of deciduous teeth. Higher concentrations of the metals were found in the maxilla permanent and deciduous teeth than in the mandible ones. 相似文献
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Summary. Cytinus ruber (Fourr.) Fritsch is described and illustrated. Current knowledge of its phylogeny and systematics is discussed, and its successful cultivation is recorded. 相似文献
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