Siegmar -W. Breckle

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The beech (Fagus sylvatica L.) is the dominant tree in Middle Europe under many different ecological conditions. But like other tree species, it is suffering in the last ten years increasingly by air pollutants including heavy metals which have been deposited and accumulated for decades in many forest soils. Increasingly mobilized by acidification(More)
Along the west coast of South America mangroves are found only outside the area influenced by the cold Peruvian Current. At 6° S (near ‘Cerro Illescas’) the current turns west to the open sea in the direction of the Galapagos Islands. Dense mangrove vegetation with a tree height up to 15 m occurs only north of 3° 35′ S from the delta of the river Tumbes(More)
Concentrations of Cd, Pb and Zn were determined in stem wood of beech trees (Fagus sylvatica L.) from 3 sites in northern Germany. Distinct radial distribution patterns of the elements were observed in the xylem. Concentrations of Cd and Pb increased from the youngest, outermost annual rings towards the center of the stem. With Zn intermediate(More)
Concentrations of Ni were determined in xylem and phloem of Quercus ilex trees growing on serpentine and sandy loam soils of northeast Portugal. Radial distribution patterns of Ni in stemwood were compared to variations in annual growth increments of the trees. Concentrations of Ni in xylem and phloem were higher in Q. ilex from serpentine soil, when(More)
Using a voltammetric procedure described previously, the radial distribution of Cd, Cu, Pb and Zn in annual growth rings of oak from two regions has been investigated: an unpolluted region in Valdivia (Chile) and a polluted region in Königstein (Taunus, FRG). The very low metal levels found in oak wood from the Valdivia region have necessitated that the(More)
Extension growth of tap-roots, initiation of lateral roots and extension growth of first lateral roots were investigated with young radish plants (Raphanus sativus cv. Rex) in aeroponic growth cabinets. Growth was not affected by 50 mM NaCl. At higher NaCl concentrations the three growth processes were adversely affected, but not at the same magnitude:(More)
ein Fflnftel der des isol ier ten na t f l r l i chen , ,Amele t ins" bet rggt . Eine weitere Dos i s e rh6hung ff lhrte zu keiner vers t i i rk ten Wir kung. H e x a p e p t i d I war d i i n n s c h i c h t c h r o m a t o g r a p h i s c h mi t , ,Amele t i n " sowie mi t e inem u n a b h g n g i g yon W e i ns t e in synthe t i s ie r ten , ebenfalls(More)
The distribution ofCystopteris fragilis andC. dickieana in Afghanistan within the Flora Iranica region is studied. The latter species, for some ecological reason, occurs more frequently at higher altitudes. In both taxa higher polyploid levels also occur at high altitudes. The phenomenon can be correlated with the boreal-arctic distribution pattern.(More)
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